Horticulture

While other scholars have traced these tendencies, like that of localism, to libertarian and neoliberal ideologies, this chapter emphasizes the autonomous Marxist and social anarchists framings of strategies towards justice, many originating out of broader global social movements. Alternative economic analyses are complicated and thickened with the increase in the importance of cultural and racial politics in food movements. Activists have seen alternative food initiatives , and particularly urban gardens as a means to value marginalized cultural and racial identities, bring different communities together, and support cultural place-based resistance to racism and marginalization. For other organizers AFIs have been a space for challenging racial discrimination and marginalization through community struggles for self determination or recognition like the work of food justice organizing in Oakland and Detroit . Many argue AFIs can and do represent spaces that go beyond cultural preservation or the bringing together of different communities; they can be built as places where communities can self-organize and provide mutual-aid when the state and civil society are oppressive.

And yet,square pot food activism in many ways is still dominated by white discourses and faces. Debates within food justice and food sovereignty organizing have highlighted the questions of the future of dominant cultures, spaces of difference and spaces of self determination in food movements. Finally, in response to social-justice blind, bio-centric approaches to the environment common in some parts of the food movement, activists have fought for the importance of socio-ecological justice. sustainability has been a central pillar of alternative food movements since the 1960s, and for many this commitment is bound to one for justice. For food sovereignty activists and many urban agriculture advocates, food politics represent a way to seek a form of justice that values socioecological change for holistic well-being. Socio-ecological justice calls into question the divide often created between humans and nature. Agroecologists offer cultivated landscapes that produce food as an example. Agroeoology is increasingly presented as a field that is concerned with a form of sustainability that values agricultural systems based on just socio-natural practices . What follows is a description of the genesis of three iterations of the US alternative food movement in its search for better relationship to struggles for justice: the community food security movement, the food justice movement, and the food sovereignty movement. Anti-hunger activists in the US have advocated for a variety of approaches to fighting hunger including state entitlement programs, charity emergency food sources, community-based strategies to provide access to healthy foods, and direct action, such as civil-disobedience that demands the right to food.

These different approaches embody the political commitments and engagements with justice of food security activism. In response to the global food crisis in the early 1970s the United Nations organized the first World Food Conference to discuss international action. At the conference the term “food security” was introduced . Many nations adopted food security as a policy goal at the same time that they advocated for a right of freedom from hunger. Food security was conceived as a complementary political strategy to advocate for a nation’s ability to produce sufficient food so that no person experience hunger . The U.S. government first used the term food security in the early 1980s. Policy makers recognized the need to not only address hunger but also the social conditions that gave rise to it . Food security was defined as “a condition in which all people have access at all times to nutritionally adequate food through normal channels” . Unlike many of the nations that adopted the food security framework, the United States did not make a statement of people’s right to food . In response to growing problems with food insecurity and the lack of sufficient government efforts to address these problems, community activists, students and anti-hunger advocates united under the banner of community food security. The catalyst for this coalition was provided by the work of Robert Gottlieb and his students out of University of California Los Angeles .

While conducting interviews on community concerns following the 1992 Rodney King beating, the group uncovered a great deal of concern over food access, affordability, and quality. After developing a report highlighting concerns and strategies for change, several researchers met with other individuals and anti-hunger groups to discuss new directions for food security organizing . In 1995, a coalition of advocates met to develop and promote the Community Food Security Empowerment Act “as the conceptual basis for solving food-system problems” . Together they drafted a food security policy statement included in the1995 Farm Bill, which defined community food security as a condition in which “all persons obtain at all times a culturally acceptable, nutritionally adequate diet through local non-emergency sources” . Then in 1996 various community-based initiatives united under the banner of the Community Food Security Coalition. As an alternative to dependence on diminishing classical food entitlements and emergency food, coalition members introduced a variety of community-based solutions, such as urban gardening and local policy-based solutions . The Coalition and other food security organizations aimed “to create community-based ways of providing food in an affordable, sustainable, and ecologically sensitive manner” . This integrative framework is concerned with both production and consumption . It takes a long-term, preventative approach to creating community-based systems that will promote conditions of food security even during times of hardship. Many projects focus on food self-reliance as opposed to an emphasis on entitlements . Part of this shift can be identified with a critique of charity that led community food security activists to seek community-based solutions. Both individuals seeking food and charitable organizations distributing food must comply with a myriad of standards and procedures that make it difficult if not “materially impossible” to be political advocates for structural change . As a result of growing problems with hunger and poverty,drainage collection pot academic and community groups undertook efforts to document and map the lack of access to food. Community food assessments have been used to demonstrate food insecurity and highlight strategies for change. In a 2010 review article, Walker, Keane, and Burke identified thirty-one articles published using CFAs to assess the presence of food deserts. The term “food desert” first appeared in the early 1990s. Short, Guthman, and Raskin stated that food desert has been used to refer to defined geographical areas lacking a large supermarket. Other studies have used the term to describe the type and quality of food available in a given area, as opposed to the characteristics of or simply the lack of food stores . 6 For most community food security activists the essential question focuses on why food distribution is determined by these issues of profitability and not issues of need. The term “food deserts” became an important political tool for activists in highlighting the problems many US residents face in accessing adequate food resources.

While activists focused on inequality of access, some scholars and advocates critiqued the heavy focus on developing solutions like mobile grocery stores or bringing back large retailers to the inner city. Short, Guthman, and Raskin provide an example of this critique. The authors argued excessive emphasis has been placed on the supply side rather than the ability of residence to pay. In their study of small full-service food retailers in the Bay Area, authors found that these stores can provide nutritionally adequate, culturally appropriate and affordable foods. The authors claimed these stores are frequently ignored in CFAs. Many storeowners noted that fresh foods were not large profit items but instead they felt ethically required to carry these items. Small, full-service food stores can contribute to community food security but attention must be paid to both the supply and the economic and social ability of community members to pay for or access fresh foods. Critiques of supply side arguments have helped food movement actors refocus on underlying structural inequalities that create not only food insecurity but also housing insecurity, health inequalities, and other injustices faced by low-income communities. Responding to movement demands, congressional Representative Eligio “Kika” de la Garza worked with 17 bipartisan co-sponsors to introduce and support the Community Food Security Empowerment Act of 1995 . In the 1996 Farm Bill, Congress allocated $16 million for a seven-year period and empowered the USDA to create the Community Food Projects Competitive Grants Program . The program works to develop community leadership among non-profits working towards food system change by granting organizations a one-time infusion of federal funds . In the first ten years of the program over 240 projects were supported to “meet the food needs of low-income people, increase the self-reliance of communities in providing for their own food needs, and promote comprehensive responses to food, farm, and nutrition issues” . Non-profits were funded to create community-based solutions to food insecurity such as rural or urban agriculture training centers. According to the USDA, the CFPCGP differs from many other agency projects in its emphasis on evaluation and technical assistance. In order to ensure that non-profits are using tax payer money wisely, the USDA has sought to ensure projects accurately and sufficiently work to document the progress of their efforts and train other communities in their methods . Much of this work has happened in partnership with the Community Food Security Coalition that developed detailed evaluation tools and trainings for grantees. In 2006, ten years after the start of the CFPCGP, the USDA announced it would eliminate the use of the word ‘hunger’ from its food security assessments . The agency claimed that the move was based on the technical difficulties and inability of the current data collection tools to accurately capture information of hunger. Hunger had been defined in medical terms so that clinicians would presumably be able to measure and provide data that demonstrated physical evidence of the experience of hunger. This medicalized approach was criticized in the 1980s by anti-hunger advocates for waiting until hunger created irreversible damages in individuals to identify a problem, focusing on physical symptoms as opposed to social signs of trouble, and failing to recognize the household and community as important scales of impact . As such, the adoption of data collection on community food security, as a social condition of lack of access to food, provided an important addition to research on the effects of hunger, a physiological state in individuals . The move to eliminate the term hunger from USDA assessments was highly contested by food activists. The issue of concern can be read as what critical political ecologists have called one of framing and problem closure . This political ecology approach challenges the objective explanations of biological and environmental research by exploring social and political contests of such scientific investigation . Scientific research engages with an object of study using “social derived instruments and metrics” and “knowledge of health and environmental problems necessarily reflects the manifold social relations that affect science” . Contexts, interests, and values influence how scientists frame the problem and object of study. This framing impacts the potentials for future research and political work derived from such research . When such framing is limited in specific ways it directs future research of a particular problem’s causes and effects into those limited directions, causing problem closure . Guthman describes the impact of problem closure on obesity research as directly connected to food access and the built environment. Obesity as a problem is automatically connected to a predefined solution of increasing access to fresh fruits and vegetables and greater opportunities for physical activity, which are expected to decrease caloric intake and increase expenditure .For anti-hunger and community food security activists, the move to remove hunger from USDA assessments raised questions as to the political consequences of narrowing the scope of scientific research . The manner in which the USDA, as a leading scientific and political body, frames the issues “determines the importance attached to them and how they are addressed; data defines and delimits the problem” . Allen asked: “If hunger is no longer an analytical category, how does one talk about it or advocate for its elimination? How does one make policy claims about something for which there is no data and which, therefore, does not exist in policy science terms?” . The reframing of hunger to very low food security reduced the ability of advocates to use the term as a rhetorical tool, one that once had significant social power.

Harvey claimed, “if the seeds of revolutionary transformation must be found in the present and if no society can launch upon a task of radical reorganization for which it is not at least partially prepared, then those internal contradictions provide raw material for growing an alternative” . To construct a utopian dialectics that engages concerns for both spatial form and social processes of alternatives requires “a dialectics that can operate in relation to both space and time” and requires a commitment to the political importance of closure, deciding on strategy and acting upon it . Harvey described praxis as engaging a dialectic of ‘either/or’ not ‘both/and’, in which actors must recognize that we exercise authority and create or destroy possibilities through the determination of spatial forms . When we decide on an alternative and build it through social processes into material reality, we both open space for potential and make a definitive decision that closes out other options. When a gardener chooses to occupy a vacant lot without landlord approval, this both creates a physical garden and relationship of gardeners and neighbors to this formerly vacant space,vertical tower for strawberries and closes out other possible uses for that lot or for relations to the landlord or neighbors.

This is nothing that should be shunned. It is a moment of seizing power as an agent of change. Gardeners, on the level of an individual organized garden project, make these decisions about closure and direction and articulate their relevance to social movement strategy. Yet when discussing land politics beyond their immediate projects, many gardeners in this study, both of and outside of the anti-authoritarian trend, would prefer a conceptual commitment to openness to using various forms of accessing land. Yet, gardeners’ focuses on their particular circumstances still may contribute to coordination and movement building. Harvey envisioned shifts in both thinking and action occurring in multiple communities, originating out of particular circumstances and struggles, and building to broad-based political movements . He labeled these individual communities’ struggles “militant particularisms.” Out of their work, Harvey theorized that many communities develop universal alternatives that they apply to global manifestations of their particular problems. Universality exists in dialectical relation to particularity. Instead of critiquing universalism, Harvey suggested we focus our attention on the mediating institutions that translate between militant particularisms and universality. It is the creative tension between the two that offers opportunity for utopian architects to “force mediating institutions and spatial structures to be as open as possible” . This moment of translation constitutes a key departure point towards emancipatory or repressive possibilities.

It is through translation, choosing to express a universal as politically necessary, that we commit to a judgment and decision, a ‘material praxis’ in that moment . It is in this moment of political judgment that this dissertation turns to the actor, the gardener engaged in what builds to a broader movement for urban agriculture, for critical analysis. These moments of judgment, choices in practice, discourse, lease agreements or occupations, demonstrate the ‘material praxis’ of the urban utopian imaginary of gardeners. In the coming chapters I describe how gardeners frame and enact politics of possibility. Rather than simply conclude that urban gardening as a regional movement is creating a sweeping break from oppressive social relations, or that gardeners, like other food activists, have accepted a limited ‘politics of the possible’, I document the multiple, sometimes contradictory meanings in the politics and practices of gardeners. In this analysis my argument builds upon a contradiction of seeing gardening as being both emancipatory and continuation of oppressive social relations. I go beyond reiterating this contradiction to argue the constellation of organized garden projects engaged in the Bay Area urban agriculture movement represent a diverse group of interests which have little coordination or communication across the projects on the question of social movement strategy with regards to land politics. Moments of closure, enacting gardens in a place are so particular to garden site or potentially to the network of gardeners in their municipality, that urban agriculturalists are not collectively engaged with the question of universal ideals for land tenure or urban governance.

This dissertation engages a regional analysis of activism in the San Francisco Bay Area, long known for its importance in the alternative agrifood movements of the last half-century and a focal point in the renaissance of urban agriculture since the 1990s. Today, hundreds of organized garden projects populate the landscape of major cities and smaller municipalities throughout the region at the same time investment in the built environment has continued to grow. The region of study includes the five southern Bay region counties including San Francisco, San Mateo, Santa Clara, Alameda, and Contra Costa counties. I pay particular attention to the policy and legal frameworks developed by gardeners in the three largest municipalities in the region: San Francisco, San Jose, and Oakland. While the dissertation more uses a regional analysis, Chapter 5 engages a comparative framework drawing out differences from these three municipalities. In this introductory section, I frame the essential history of the region and these three municipalities and then build upon it in the coming chapters. For gardeners a notable element of the Bay Area’s geography is the Mediterranean climate which allows for year round production, something many other US metropolitan areas do not enjoy. The climate has been an important factor in the growth of agricultural industry in the Bay in the nineteenth and early twentieth centuries . But several other factors have also been important in building the rich social, political, and economic conditions in which organized garden projects in this region grow. Most notably the rise of the Silicon Valley has been a determining force in the economic landscape of the region, fueling the explosion of competitive land markets in three largest municipalities in the Bay. While all experiencing these effects, different histories in each municipality have created particular conditions leading to distinctive articulations and practices of urban agriculture across the region. To understand the struggles of land and property in which gardeners engage, one must frame the contemporary real estate markets and tax policy in the region in context of the economic and social history of the three largest municipalities. Oakland has been a bay area focal point for manufacturing and maritime industries since the early 1900s, and with significant growth in these sectors during WWII, Oakland began attracting many African American migrants from the south. While redevelopment projects in 1950s and 60s displaced many African American and Latino residents, the city’s non-white populations continued to grow in the industrial flat lands of North, West, and East Oakland. Oakland became a minority majority city, peaking with almost 50% of the population of African descent in the 1980s. Today, that progression is reversing as a consequence of socio-economic trends described below. San Francisco also experienced growth as a Naval port city during WWII and began massive redevelopment projects in the 1950s and 60s. Resistance to redevelopment grew quickly and contributed to the development of city politics focused on preservation of city neighborhoods from the violent impacts of capitalist growth politics . Amidst a wash of progressive social movements for environmental protection, gay rights, and civil rights,container vertical farming activists imposed limits on capital, winning many major victories against redevelopment and displacement from the 1950s to early 2000s, and yet the activists were not able politically defeat the growth coalition which has increasingly gained ground since . Investment stemming from growth in the tech industry has had an increasing impact in San Francisco growth politics, a force our southern most bay area municipality has been shaped by for a half century. San Jose’s economic history has been dominated by the development of the technology manufacturing and related industries, and since the 1970s the city and county has looked to tech industry as both the top employer and source of charitable giving.

It is to the genesis of the tech industry that we first turn. Starting in the 1970s in San Jose, Chicanos and other ethnically marginalized communities experienced the social consequences of economic development putting the south bay on map: the rise of the tech industry. By the late 1970s through the leadership of Stanford University and funded by national defense contracts, Santa Clara County was well under way in its transformation to Silicon Valley . Tech’s early promise of economic development and environmental benefits only came true for a segment of the population. For employees and largely Latino, Chinese, Vietnamese and non-white communities in the Valley it resulted in low-wage employment, toxic working conditions, and high environmental costs . In the 1980s a coalition of tech workers, community members, and environmentalists fought a landmark environmental justice battle to contest groundwater contamination caused by leakage of underground tanks holding toxic byproducts from computer chip production. In response the California legislator passed policy to begin cleaning up and regulating Silicon Valley’s environmental impact, as the tech industry continued to grow.As the first tech industry explosion was occurring, in 1979 CA passed proposition 13 severely limiting property tax revenues and causing the state to favor commercial development over residential for potential tax earnings . Simultaneously, regional municipalities embraced the economic promise of Silicon Valley. To attract development cities have offered incentives to tech industries, including low annual business taxes . While in the 1970s- 80s, Florida and Kenney found the Silicon Valley rich with venture capital and tech innovation, by 2013 Florida was asking ‘is San Francisco the new Silicon Valley’. Today, a regional housing crisis is underway as middle class San Franciscans and Silicon Valley tech workers spill into surrounding communities . At the same time tech-centered Peninsula towns have resisted creating large company housing developments, such as Mountain View’s 2012 rejection of including housing developments near Google, refusing the idea of creating or becoming a company town . Extreme housing prices have contributed to a widening wealth gap, which in San Francisco is growing faster than any other city in the nation . Between 2007 and 2012, the 20th percentile of earners in the city lost $4309 of household annual income while the 95th percentile gained $27,815 . The wealth gap is contributing to an uneven landscape of food security with significant problems with food insecurity in communities like East San Jose, Bayview-Hunters Point, West Oakland, East Palo Alto, and other communities.The crisis of affordable housing, the housing market crash, and predatory, race-based lending practices have caused a wave of rapid gentrification in communities in San Francisco and Oakland. Nationally, as a result of the 2008 housing crisis it is estimated that African Americans lost $71 to $93 billion in assets . Oakland lost over 40% of their African American residents between 1990 and 2011, with a drastic speed up since the housing crisis . There were over 10,000 foreclosures between 2007-2011, 93% of which occurred in predominately African American and Latino flat lands communities. These Oakland residents are increasingly moving to surrounding suburbs in search of more affordable housing . At the same time residents were priced out of San Francisco and new tech employees were looking for housing in the increasingly popular flat land communities. In 2014 Google tested ferry services to transport Oakland workers to Silicon Valley, in addition to running an alternative ground transportation infrastructure, the “Google buses”, throughout the region. Lively protests, direct action, and public debate over Airbnb, evictions and tenant rights, and the “Google buses” have gained national attention. On September 25, 2014 a Facebook video went viral of white Dropbox and Airbnb employees repeatedly asking Latino youth to leave a public soccer field in the Mission because they had reserved the site online . When the youth and an African American young adult advocate suggested the white men join their game but that because the field was public they wouldn’t leave, the men were incredulous, insisting they had paid the $27/hour fee for the reservation and should be able to use the field. The video spread quickly with vitriol filled comments about the racism of gentrification in San Francisco, leading to apologies from at least one of the white players involved, and more significantly a reversal of the “Pay to Play” reservation system the Recreation and Parks Department had instituted. The policy still stands at several other San Francisco fields. Today’s debates over urban space have reached electric levels and are reflected in the debates of urban gardeners, as we will see in the coming chapters.

Our estimation strategy follows Angrist and Pischke , who advocate the use of two alternative approaches for dealing with omitted variable bias in panel data. The first employs a lagged dependent variable to account for the possibility that the subsidy was targeted based on pre-treatment trends in party support. The second uses a difference-in-difference model that eliminates possible confounding by time-invariant individual characteristics and controls for a number of time variant factors that might be correlated with the treatment and party preferences. In conjunction, these approaches are useful for bracketing the estimated effect when the potential sources of omitted variable biases are unknown . The two approaches produce estimates of a statistically-significant treatment effect ranging from 6.2% to 7.5%. The first specification, which we refer to as the lagged-dependent variable model, accounts for a large number of potential confounding variables,vertical gardening in greenhouse drawing both on existing studies of electoral preferences in Africa and on the analysis presented in the previous section. We include all variables from the analysis of targeting in the previous section, as well as several other covariates.

We briefly explain the rationale for their inclusion. Unless otherwise specified, we measure these variables using data from the 2008 survey, prior to the distribution of the 2009/10 subsidy. First and foremost, it is important to include the measures of party support from the first survey round. We speculate that those who did not feel close to any party in 2008 might be more responsive to the subsidy, given weaker pre-existing party ties. Likewise, we expect that opposition supporters might be particularly resistant, given their pre-existing attachments. It is also important to account for ethnicity, given that members of some communities might be more likely to become DPP supporters for reasons other than the subsidy program. In particular, members of the president’s own ethnic group might be more likely to follow Mutharika to the DPP than members of other communities. The Chewa, who have long been associated with the Malawi Congress Party , might be particularly disinclined to become DPP supporters. The Yao might also be particularly disinclined to become DPP supporters given the acrimonious split in 2005 between president Mutharika and former president Bakili Muluzi, a Yao. Finally, since the demise of the AFORD party following the 2004 elections , the Tumbuka have been less tied to a particular political party and might therefore be more likely to move toward the DPP. In addition, we include a measure of whether individuals come from minority groups within their villages.

We also include a number of variables found to be associated with subsidy reception based on our analysis of targeting in Figure 1. We account for the possibility that individuals with local political ties might be more likely to become DPP partisans by controlling for membership on district development committees, village development committees, and the chief’s council. We also account for individual economic shocks – loss of crops, loss of income source, and the death or illness of a family member – that might reduce support for the incumbent party, based on research from the United States that shows that voters punish incumbents when their personal well-being is affected by natural disasters and other unforeseen events . We include measures of these shocks in both 2008 and 2009 . We also include variables that track participation in the many other government anti-poverty programs in Malawi to account for possible correlation with subsidy reception. Specifically, we account for participation in the following programs : free food/maize distribution, food-for-work, inputs-for work, scholarships for secondary education; scholarships for tertiary education, and direct cash transfers. We include a measure of subsidy reception in the previous year to account for the possibility that the 2009/10 subsidy may have targeted individuals whose views of Mutharika were in transition due to the prior year’s subsidy.Finally, we account for demographic factors – age, education, farm size, income, and households headed by women – that could affect the strength of pre-existing partisan ties and therefore the likelihood of changing partisan allegiances. In the previous section, our analysis showed minimal evidence of targeting with regard to variables measured in 2008.

However, because multicollinearity between variables could reduce the significance of variables in the targeting model, we test for differences between control and treatment groups on each variable individually and add those that were not included in the analysis of targeting. Following Ho et al. , we test for differences of means and differences in distributions . The balance statistics reveal statistically significant differences on several covariates, indicating the need to control for these factors. We estimate a logit model of DPP support in 2010 that controls for all variables described above and includes village fixed effects to account for possible targeting across villages in our survey area. We cluster standard errors by household. The results, presented in column 1 of Table 3, show an estimated treatment effect that is significant at the p<.05 level. Full logit results are shown in Table A2 in the on-line appendix. As an alternative way to address covariate imbalance, we employ matching before estimating the effect of the subsidy on party preferences using the LDV approach. For this we use the Coarsened Exact Matching approach developed by Iacus, King, and Porro . Matching works by creating matched pairs between those who received the 2009/10 subsidy and those who did not that are similar along observed covariates. Respondents that are not matched are excluded from the analysis, thereby improving overall balance on relevant factors between the treated and untreated groups. The advantage of matching is that one can account for possible confounds through pre-processing rather than controlling for confounds in a parametric model. The parametric approach relies on assumptions about the functional form between confounds and the outcome variables, which if incorrect can bias the estimate. Matching, by contrast, makes no such assumptions . We match on variables that we consider to be most relevant based on theoretical importance and the balance statistics shown in Table A1 in the on-line appendix: region, prior partisanship, membership in the village development committee,greenhouse vertical farming whether respondents experienced an illness or death in the family within the last two years, female-headed household, and age. We limit the matching to this set of variables because including additional variables greatly reduces sample size and because we are able to improve imbalance by matching on this set of variables . We use matching with replacement, which has the advantage of producing better matches and dropping fewer observations than one-to-one matching .We account for remaining imbalance by including all covariates in the estimation of the treatment effect, as recommended by Ho et al. . Column 2 in Table 3 presents the results from a logit model employing the matched data. The model produces a similar estimate of the treatment effect , comparable to the estimate in the pre-matching results, and again the estimated effect is statistically significant. The second estimation strategy uses a difference-in-difference approach designed to account for all time-invariant individual-level factors that could be correlated with both subsidy reception and party preferences. For this, we estimate a pooled OLS model that includes a dummy variable for treatment condition, a dummy for the time period, and the interaction of the two.

Specified in this way, the model is equivalent to a two-way fixed effects model that includes both individual fixed effects and a period dummy. With this specification, the only potential omitted variables of concern are time-varying factors that might be correlated with both treatment status and partisan preferences. As in previous models, we include measures of economic shocks that occurred between the two survey rounds and which might be correlated with both subsidy reception and party preferences. These include measures of whether the respondent’s household experienced a loss of crops or livestock, the loss of an income source, or the death or serious illness of an adult family member. We also include measures of household participation in a host of other government-sponsored anti-poverty programs: food distribution, food-for-work, inputs-for-work, scholarships for secondary and tertiary education, and cash transfers. All time-invariant factors from previous models – such as gender, education, ethnicity, and village – are excluded by design as these factors are accounted for by the specification. The results, shown in column 3 of Table 3, indicate an estimated treatment effect of 6.2% that is again significant at conventional levels .In this section we discuss the limitations of our estimation strategy and relate our findings to relevant literatures. With regard to the methods used to identify the effects of the subsidy on political orientations, the main limitation is that because the program was not randomly distributed, we cannot entirely rule out omitted variable bias with regard to unobserved factors. To address this concern, we use the sensitivity test developed by Rosenbaum to estimate the extent to which our results are potentially driven by one or more omitted factor. This test estimates how large an effect one or more omitted variables would have to be to overturn the estimated treatment effect. For this analysis, we re-estimate the treatment effect using the LDV approach after conducting one-to-one matching on the same set of covariates used above . The results again indicate a statistically significant effect of the subsidy on preferences, with the estimated size of the effect being somewhat larger. The Rosenbaum bounds test shows that one omitted variable would have to increase the likelihood of respondents receiving the subsidy by 16%, after having already accounted for the rich set of covariates we use as controls, in order to overturn the finding. There is no agreed standard for evaluating the results of Rosenbaum bounds. We can, however, compare the results to other known factors that affect assignment. Looking at the marginal effects of factors found to be statistically significant in our analysis of targeting , we find that those who had experienced an illness or death in the household in the last two years were 7.8% less likely to benefit, and households headed by females were 10.4% less likely to receive it. Thus, to overturn the positive finding on the effect of the subsidy on preferences, one or more omitted variables would have to exert a larger effect on assignment than these covariates for which we have measures, after having accounted for these factors and all others included in the estimation. While not impossible, it seems unlikely that our findings are due to omitted variable bias, given that none of the measured covariates exerts an effect of this magnitude. A second limitation relates to the short duration of the period under study. Ideally we would like to know the full extent to which the program affected partisan attachments and electoral behavior. Our data, of course, only allows us to examine the effects of the program across a two-year time span. It is reasonable to believe that the effects we identify likely hold more broadly across the program’s implementation. However, it is also possible that the effects will diminish over time as the program becomes a more routine aspect of Malawian life. It is also possible that the program will have less of an effect during periods when the party system is more stable. It is particularly important to note with regard to the enduring effects of the subsidy that the death in office of president Bingu wa Mutharika in 2012, and the subsequent struggle over succession created a disruption to the political continuity of claiming credit for the AISP , even though the program itself continued. In the 2014 election, two of the main parties promised to continue some version of the AISP going forward. Mutharika’s brother and the DPP presidential candidate Peter Mutharika boasted during the 2014 election campaign that his party had a “good track record” in managing the program and promised not just to continue the AISP, but to abolish the coupon program and expand the subsidy so as to “make the subsidized fertilizer available to every maize subsistence farmer who needs it” . Then-president Joyce Banda and her ruling party proposed during the election campaign that in the next administration the fertilizer program would be scaled back, offering fertilizer loans instead of subsidies . Though covered in major party manifestoes, the AISP was not a central issue in the 2014 election campaign. Instead, voters and politicians alike were pre-occupied with a major corruption scandal implicating the Banda administration .

Wages fall by only 0.5% in El Salvador but nearly 3% in Guatemala, 8.5% in Nicaragua and 26% in Honduras. Because of these wage decreases and an imperfect transmission of output price changes across households, subsistence grain production increases by 1.8% and 2.1% in Guatemala and Nicaragua, respectively, while remaining almost unchanged in El Salvador and Honduras. This finding is reminiscent of what occurred in Mexico after NAFTA: a decrease in the market price of maize was associated with an increase in maize production on rainfed farms . Dyer, Boucher, and Taylor refer to this as a “retreat into subsistence.”In response to decreased profitability in the previously protected importables sectors, rural producers channel their resources into other crop and non-crop activities and migration. The cross-effect of tariff elimination on other activities varies across households and countries. All groups with a significant participation in traditional-crop production prior to reforms increase their production of these goods. In El Salvador, small and medium commercial households increase their production of traditional crops by 3.3% and 0.9%, respectively. In Guatemala,plastic pots 30 liters production of traditional crops increases between 7% and 45% ; in Honduras, between 0.6% and 17% , and in Nicaragua between 31% and 51% .

Output of non-traditional crops increases more, although from a smaller base. Total rural out-migration increases by 7.6% in El Salvador, 1.1% in Guatemala, 0.3% in Honduras and 0.6% in Nicaragua. The major difference between the extreme and intermediate scenarios is that the latter maintains tariffs for maize in Honduras, for rice in Guatemala and Nicaragua, and for milk products in all four countries. As a result, commercial production of grains in Honduras falls less under the intermediate than the extreme scenario. In Nicaragua, grain production now falls by 4.7% in small commercial households and by 9.7% and 3.3%, respectively, in medium and large commercial households . In Guatemala, where maize trade is liberalized under both scenarios, there is little difference between the two. However, there are substantial differences between scenarios in El Salvador, where livestock production is relatively important. Grain output now falls in large commercial households, and it decreases more than under the extreme scenario in medium households. This result illustrates the way in which non-uniform implementation of trade reforms can create new distortions on the production side, as the newly liberalized activity becomes less profitable relative to the protected activity .

A similar result is evident in Honduras, where under the intermediate scenario the tariff on maize imports persists while that on beans is eliminated; maize production increases, while bean production by all commercial households contracts sharply. Rice production by all commercial households in Honduras also decreases more sharply here than under the extreme scenario. Under the low scenario, tariffs are maintained for maize, rice and small livestock but eliminated for beans and large livestock. This mutes the negative production effects in all four countries. Basic grain production is almost unchanged in El Salvador. There is little difference in production effects between the intermediate and low scenarios in Honduras, where maize tariffs are maintained under both. Negative grain production effects become positive for medium commercial households in Guatemala and for subsistence and large commercial households in Nicaragua, once again highlighting the complexity of effects when trade reforms are not uniform.Income effects are summarized in the left-hand panel of table 6. Under the extreme scenario, nominal income falls for all household groups in all four countries. In three of the countries , large commercial producers are hardest hit by agricultural trade reforms. This group’s income falls by 4.9% in Nicaragua, 8% in Guatemala, 8.7% in Honduras and 24.1% in El Salvador. The sharp drop in nominal income for large commercial households in El Salvador reflects these households’ production concentration in livestock and livestock products prior to reforms. 

Medium commercial producers also suffer relatively large nominal income losses in El Salvador, Guatemala y Nicaragua . In Honduras, the biggest losers are landless households, which rely heavily on agricultural employment , followed by medium , small and large commercial farms. Nominal incomes of subsistence households do not change in El Salvador and decrease by only 0.5% in Honduras and 1.0% in Guatemala and Nicaragua. These households lose primarily because of the decrease in rural wages. Lower wages, however, partially counteract a negative income effect on subsistence production. As a result, the supply of basic grains either does not change or else increases slightly . In Honduras, under the intermediate scenario the income of subsistence households changes little and that of commercial households decreases far less than under the extreme scenario. Small commercial households lose 4.6%, compared with 10.1% under the extreme scenario. Medium commercial households lose 2.7% , and large commercial households lose only 1% . Clearly, the maintenance of tariffs on maize imports protects Honduran commercial household incomes but has little effect on subsistence households. In the other countries, where the intermediate scenario includes liberalization of maize trade, the income effects are similar to those under the extreme scenario. Minimal impacts of trade reforms on production are mirrored in the household income results under the low scenario. Decreases in nominal incomes do not exceed 1% for any rural Salvadoran household group or any subsistence household group in the four countries.

Among commercial producers, decreases in nominal income under the low scenario range from 0.5% to 2.5% in Guatemala, from 0.9% to 4.4% in Honduras, and from 1.1% to 3.6% in Nicaragua.A decrease in food prices has an ambiguous effect on welfare in an agricultural household model, as positive effects of decreases in consumption prices may counteract the negative income effects described above. Which effect dominates is an empirical question. Assessing rural welfare effects of agricultural trade reforms is particularly complex in a general equilibrium setting, because both quantities and prices are changing. We employ a general-equilibrium version of the compensating variation to estimate the rural welfare effects of CAFTA’s agricultural provisions. By introducing a GEVC slack variable into each household’s budget constraint and holding utility constant before and after the simulated reforms, one obtains the transfer required to compensate households taking into account all quantity and price adjustments captured by the DREM. A positive value of the GECV implies that welfare decreases as a result of the reforms—that is, the negative income effect dominates the positive consumption-price effect. A negative GECV implies the opposite. Estimated GECVs are reported in the right-hand panel of table 6. Despite a decrease in nominal income for all rural groups under the extreme scenario,round plastic pots in the majority of cases the GECV is negative, implying that rural household welfare increases. This reflects the fact that income decreases are much smaller in percentage terms than the decreases in prices that result from tariff removal. For example, in El Salvador small commercial households reap a benefit from agricultural trade reforms equivalent to 10.3% of their income prior to the reform. Effects on medium and large commercial households and on landless laborer households are smaller but nonetheless positive. In all countries except Honduras, the total GECV is negative under the extreme scenario, ranging from 1.5% to 5.7% of base income. In Honduras, lower consumption prices are not sufficient to compensate for a sharp decrease in wages for rural worker households, and the GECV is positive .The compensating transfer is small and positive for large commercial producers in Guatemala, nil for subsistence households in El Salvador, but negative for all other rural household groups. Under the intermediate scenario, the GECV is negative for all groups except small and medium commercial households in Honduras and large commercial households in Guatemala. Under the low scenario, GECVs are zero or negative for all groups. In some cases the estimated transfer is negative and largest in absolute value under the extreme scenario, due to the decrease in consumption costs that result from immediate tariff removal. These results might appear surprising in the light of the negative effects of agricultural trade liberalization on agricultural production. However, they are not surprising when viewed from the consumption side of the rural household, which typically spends a significant share of its budget on food items protected by pre-CAFTA tariffs ranging from 10-154%.

The results of our welfare simulations suggest that the majority of rural households, in particular smaller producers, do not benefit from pre-CAFTA agricultural import tariffs.As in any simulation model, modeling assumptions and data limitations influence the results of our simulations and welfare analysis. The model assumes that rural households can reallocate resources among activities in which they participate prior to the reform. Constraints on rural households’ capacity to adjust, due for example to rural credit market imperfections, would tend to magnify the negative effects of trade reforms. Indeed, in the majority of cases, positive cross-sector effects presented in table 5 are smaller in subsistence and small-commercial households than in larger commercial households, even though liquidity constraints are not explicitly incorporated into the model. For example,in Honduras, small commercial households change their production of traditional and nontraditional agricultural goods only slightly in response to the removal of import tariffs on grains and other sensitive items, and the nontraditional agricultural supply response is more than six times greater for large than small commercial households. These considerations highlight the need for transition policies to facilitate rural adjustments to trade reforms, particularly for small-producer households in which adjustment constraints are likely to be most severe. Long-term exposure to ambient fine particulate matter is associated with elevated health risks such as respiratory and cardiovascular diseases, resulting in more than four million premature deaths globally each year . Of these, 10–25% are estimated to occur in India . One source of direct PM2.5 emissions responsible for Indian public health impacts is crop residue burning. As the second largest worldwide crop producer , India generates ~500 million metric tonnes of crop residue annually, of which 100 MT is burned . The practice of residue burning primarily occurs following the wheat harvest in April-May and the rice harvest in October–November , and mostly in northwestern India . Densely populated areas located downwind of agricultural fires in the Indo-Gangetic Plain , such as New Delhi, typically experience an annual mean of ambient PM2.5 concentration of 50–200 μg m−3 and episodic spikes reaching 200–1200 μg m−3 during burning seasons, exceeding the World Health Organization PM2.5 guidelines by an order of magnitude. Ambient PM2.5 exposure due to crop residue burning is specifically associated with a three-fold greater risk of acute respiratory infection in the general Indian population. Recent studies at local, urban and regional scales have shown that PM2.5 emitted from crop residue burning affects air quality not only in India but also across South Asia, including Pakistan, Nepal and Bangladesh, due to the transport by the predominantly northwesterly winds. Current regulations by the Indian government intended to reduce agricultural fires, including crop residue management, burning bans, and fines, have had limited efficacy. Unlike other crop residue, the low protein content and poor digestibility of rice and wheat residue have limited their potential for use in bio-fuel, animal fodder, fertilizer and paper production . In addition, the tight schedule of the harvest-to-sowing transition under the predominant rice-wheat rotation cropping system in northwestern India have limited the rate of adoption of alternatives. Crop residue burning allows cheap and fast disposal of crop residue and therefore remains a recurring issue, as revealed by a ~60% increase in the number of agricultural fires detected by NASA’s Aqua satellite from 2002 to 2016. Studies which can attribute air quality impacts to specific burning instances therefore help to inform targeted mitigation strategies and optimize resources for effective action on burning with minimal disruption to farmers. Substantial work has been done on air pollution from fire emissions in individual, heavily polluted locations such as Delhi. However, no work to date has related burning in each individual district to the eventual premature mortality risk and associated cost across India, where a large population experiences increased levels of pollution from fires. In addition, efforts to identify alternatives to burning have typically been qualitative or focused on national or regional measures such as adopting mechanized approaches and alternative crops. This neglects the possibility that targeted changes in the timing and location of residue burning may be able to yield significant improvements, and that there might be large differences in the downwind health impacts resulting from the same amount of residue burning from specific locations.

Consistent with scientific theory, empirical research suggests that warmer climates, such as those projected for the Southwest, will lead to more extreme precipitation intensity and frequency , particularly during the winter season . Since annual precipitation is projected to decline , more extreme events do not translate into higher total rainfall for a given year. Instead, it is projected that light precipitation — an important source for soil moisture and groundwater recharge — will concomitantly decline. Between 1901 and 2010, the areal extent of drought increased in the southwestern United State . Some have attributed the increasing expanse of drought, particularly in the previous decade, to warmer temperatures . Others have suggested that it is due to changes in atmospheric circulation . In addition to temperature and precipitation, CO2 fertilization is another climate change pathway affecting agriculture. Increased atmospheric carbon dioxide stimulates photosynthesis, leading to increased plant productivity and decreased water and nutrient use . C3 photosynthetic plants will benefit more than C4 plants ,fodder systems for cattle and dryland cropping systems will benefit more than irrigated systems .

The extent to which CO2 fertilization mitigates climate-induced water scarcity in the field still lacks scientific consensus, and there is debate on the extent to which simulating CO2 effects actually reproduces the results in free air carbon dioxide enrichment experiments . Agricultural impacts from climate change are rooted in complex pathways. Assessments of crop impacts due to climatic change fall under two, broad categories: process-based and statistical models. Process-based models simulate physiological development, growth and yield of a crop on the basis of interaction between environmental variables and plant physiological processes . Statistical crop models impute a relationship between historic crop yield and climate variables, often in order to project the impact on yield under future climate scenarios. Process-based models remain the gold standard in crop modeling as one is able to study the relationship between weather and all phases of crop growth in a range of weather possibilities, even those lying outside the historical record . California field crops have been modeled using DAYCENT . Both studies highlight resilience of alfalfa yield under A2 scenario by end of the century, whereas 5 other crops exhibit a decline. Jackson et al. also find alfalfa yield to be particularly resilient to early and repeated heat waves during May–July. Lee et al. also run climate projections with and without a CO2 fertilization effect on seven field crops in the Central Valley of California.

They assume a CO2 increase of 350 ppmv from 1990 levels enhances net primary production by 10% for all crops except alfalfa and maize. They find that CO2 fertilization increases crop yields 2–16% above the model without CO2 effects under the high-emissions scenario by the end of the 21st century. There is a much smaller yield increase under the low-emissions scenario. Lobell and Field use two estimation methods in studying the effects of temperature and precipitation on perennial crop yields. Their model includes 72 potential weather predictor variables for each crop, such as monthly averages for max and min temperature and their corresponding squares. They find that cherries and almonds are harmed by future warming out of a set of 20 perennial crops in their analysis. Crop-level adaptations — such as adjusting the planting and harvesting date , and substituting between different crop varieties — have been included to a limited extent in crop models. However, these cannot account for the broad range of decision making at the farm-level under which many of the negative effects of climate change could be partially offset with input and output substitutions, improving information, and effective water institutions. Thus, economic models are necessary to capture a broader range of responsive decision-making as the climate changes.Recently, adaptations specific to California agriculture have been studied using three economic programming models: the Statewide Agricultural Production model, Central Valley Production Model , and the US Agricultural Resources Model . Capturing the decision-making process is an important part of modeling. In programming models, the farmer’s decision is captured by the objective function.

The main decision variable in these models is acres of land allocated to a region-specific crop mix. The farmer responds to reductions in water availability and yield by adjusting crop acreage. Exogenous adaptations include institutional , socioeconomic , and technological change . Calibration through positive mathematical programming also captures decision-making by preserving observed crop mix allocation decisions . SWAP employs a PMP cost function to the capture the decision of bringing an additional unit of land into production . Both CVPM and USARM have also been calibrated using PMP . CVPM studies have also generated synthetic crop share data from Monte Carlo runs using a base water supply and groundwater depth with random perturbations. Crop adaptation equations are then derived from a multinomial logit regression of this CVPM-generated synthetic crop share data . In order to represent climate-induced changes in water supply, many mathematical programming models are linked to hydrological management models, such as theCalifornia Value Integrated Network , Water Evaluation and Planning , CalSim-II, and C2VSim. CALVIN is a generalized network flow-based optimization model that minimizes economic operating and scarcity costs of water supply, subject to water balance, capacity, and environmental constraints for a range of operational and hydrologic conditions . CALVIN has the potential to incorporate several basin-level adaptations to water allocation rules such as contract changes, markets and exchanges, water rights, pricing, and water scarcity levels. However, it has limited ability to represent important physical phenomena, such as stream-aquifer interactions and groundwater flow dynamics under different climate and water management scenarios . WEAP has many of the same water management features as CALVIN and CalSim-II. WEAP includes demand priorities and supply preferences in a linear programming framework to solve the water allocation problem as an alternative to multi-criteria weighting or rule-based logic. It is different because analysis in the WEAP framework comes directly from the future climate scenarios and not from a perturbation of historical hydrology as with the other models. Unlike CALVIN and CalSim-II, WEAP only has a simplified representation of the rules guiding the State Water Project and Central Valley Project systems . CalSim-II is also very similar to CALVIN and WEAP . C2VSim is a multi-layer,fodder sprouting system distributed integrated hydrologic model that could represent pumping from multiple aquifer layers, effects on groundwater flow dynamics, and stream-aquifer interaction . Recent programming studies focus on how certain adaptations may affect costs under relatively extreme cases of water scarcity. These studies thus assess how these adaptations may offset costs under worst-case-scenarios of water supply reductions. Given that reduction in statewide agricultural water use due to the current drought is estimated at 6% , studies on 40–70% flow reduction should be interpreted with caution. The subsequent studies are organized according to magnitude of water supply/flow reduction. Studies on 5–6% reduction in water supply reveal the heavy fallowing and groundwater use .

Howitt et al. find that a 6.6 maf deficit in surface water caused by the current drought is largely substituted by 5.1 maf of additional groundwater. This is estimated to cost an additional $454 million in pumping. In addition to over-pumping groundwater, farmers adjust by fallowing crop land. The overwhelming majority of the 428,000 acres estimated fallowed in 2014 are in the Central Valley, where the majority of fallowed acres belong to field crops. However, they project that fallowing will decrease by 43% by 2016, suggesting a trend toward stabilization. Frisvold and Konyar use USARM to examine the effects of a 5% reduction in irrigation water supply from the Colorado River on agricultural production in southern California. In particular, they are able to compare the potential value-added of additional adaptations that include changing the crop mix, deficit irrigation, and input substitution to a “fallowing only” model. They find that these additional adaptations have the potential to reduce costs of water shortages to producers by 66% compared to the “fallowing only” model.1 Medellin-Azuara et al. examine the extent to which more flexible2 versions of California water markets could reduce water scarcity costs under a 27% statewide reduction in annual stream flow. They compare agricultural water scarcity in the year 2050 under two scenarios: 1. Baseline: population growth and resulting levels of agriculture to urban land transfer.Warm-dry: includes population pressure and climatic changes under GFDL CM2.1 A2. Under the warm-dry scenario, even with optimized operations, water scarcity and total operational costs increase by $490 million/year, and statewide agricultural water scarcity increases by 22%. If water markets are restricted to operate only within the four CALVIN sub-regions, statewide water scarcity costs increase by 45% and 70% for the baseline and warm-dry scenarios, respectively. Marginal opportunity costs of environmental flows increase under the warm-dry scenario, with particularly large percentage increases for the Delta Outflow and American River. Medellin-Azuara et al. conduct a similar analysis, adding the comparison with a warm-only 2050 scenario. The agricultural sector water scarcity costs rise by 3% from the baseline to warm-only scenario, versus an increase of 302% from the baseline to the warm-dry scenario.Indeed the greater hydrological impact of the warm-dry scenario results in significantly greater scarcity costs than the warm-only scenario. Using the CALVIN model runs from Medellin-Azuara et al. , MedellinAzuara et al. analyze adaptations at the farm-level, including adjustments in crop acreage , and to a more limited extent, yield-enhancing technology . Similar to the 2008 paper, the model compares economic losses between a baseline scenario and a warm-dry scenario . Results reveal an anticipated decline in acreage of low-value crops , which is particularly severe due to the large reduction in water availability. For example, pasture acreage is reduced by 90% across 3 out of 4 agricultural regions. The results also suggest that statewide agricultural revenues decline at a proportionately lower level than the reduction in water availability . Their model also captures the complexity between crop demand and climate-induced supply reduction. Although the demand for high-valued orchard crop increases, production decreases due to the negative impact on yield from temperature increases.The resulting price increase cannot compensate for the decrease in supply, and gross revenue still declines. Two studies examine the impacts of more extreme reductions in water supply . Harou et al. construct a synthetic drought in 2020 based on the paleo-record, rather than GCM projections. Their results regarding agricultural water scarcity and environmental flows are consistent with other CALVIN-SWAP studies. Environmental flows are also extremely restricted. Marginal opportunity costs of environmental flows rise by one or more orders of magnitude with extreme drought as compared to the historic baseline, with the Trinity, Clear Creek, and Sacramento Rivers experiencing the highest increase. Average agricultural water scarcity increases 3900% across the entire state under extreme drought even under well-functioning water markets, which seems somewhat implausible and may result from an overly restrictive model. Although Dale et al. do not calculate scarcity costs, they find that a 60-year drought with 70% reduction in surface flows only moderately impacts the total amount of irrigated acreage in the Central Valley, which declines from 2.4 million hectares to 2.1 million. This suggests that Central Valley farmers tend to have a relatively inelastic groundwater demand, compensating for the loss in surface water with groundwater rather than fallowing. Within the Valley, they find that Tulare Basin has a greater increase in fallowing than the San Joaquin Basin since the former is historically more dependent on groundwater. Dale et al. are also able to capture the increase in aquifer subsidence due to increased withdrawals during the prolonged drought, suggesting that the quality of the aquifer will decline through time with excessive pumping. Joyce et al. use WEAP-CVPM to model climatic changes with 6 GCMs under B1 and A2 scenarios for 2006–2099. Unlike the CALVIN-SWAP studies, they model irrigation efficiency by assuming that vegetable and fruit and nut crops in the Central Valley will be entirely converted to drip irrigation, and half of field crops will be converted by mid-century. They find that these adaptations tend to offset increasing water demands caused by increasing temperatures and periods of drought. The model even projects a reduction in annual groundwater pumping compared to the historical period until mid-century under some scenarios.

Smallholders cannot compete. Under these conditions, they struggle to recoup the expenses of producing crops that require intensive agriculture. It is, therefore, vital that the rural poor continue to participate in self-sufficient agriculture, at least in part, given the precariousness of their ability to secure buyers at prices that will benefit them, even domestically. Risks can be reduced by continued participation in the domestic food producing sector and limited participation in the export sector. Maximizing the efficiency of domestic food production is the most direct route to ensuring food security in the region. Without demand, export-driven initiatives, such as AGRA’s pigeon pea program, simply result in net losses for smallholders and governments. Entities tied directly to profits from the sale of seed and inputs are the only beneficiaries. Some view the agricultural export model as an obvious path to success due to Ricardo’s theory of comparative advantage and recent export-led successes in Hong Kong, South Korea, Singapore, and Taiwan, sometimes referred to as the Asian Tigers. African nations are markedly different from the Asian Tigers in terms of history, politics, infrastructural capacity, and financial standing. The assumption that strategies which have worked in the Asian nations are applicable in African contexts is simplistic.

Brigham demonstrates that some nations are, in fact,hydroponic nft designed in such a manner that export-led initiatives are more likely to increase hunger, especially as it relates to the ways an export focus can impact farmer incomes and food availability. Exports, the author argues, improve food security under certain terms. These terms include that a nation has high food availability and that the agriculture sector is a non-substantial portion of the national economy. Such is the case for the Asian Tigers, which have economies reliant upon exports in integrated circuits for electronics, oil, and gold . Export driven initiatives are explicitly not beneficial in nations where the opposite is true . In Malawi and Tanzania, agriculture represents greater than a fifth of national GDP and populations have not yet achieved food security, so they do not meet the criteria for export-led success. Wealthy nations such as the United States are net food importers, while many poor nations are net food exporters, demonstrating little correlation between export quantity and success, and rather, pointing to a relationship between success and purchasing power. Surveys and focus groups of Tanzanian farmers demonstrated that among the challenges associated with participation in AGRA initiatives- including poor storage for surpluses, quality control, water supply, transportation, competing commercial producers with larger surpluses, and the purchase of inputs and fertilizers- market access was reported as the most difficult by nearly 68% of participants . Poorer smallholders command low prices for their outputs while spending significantly higher percentages of their incomes on inputs and fertilizers than large estate owners.

Such estates more consistently meet market requirements and produce volumes that are friendly to export purchasers, leading to profits that can be reinvested to buy and consolidate more land. This displaces smallholders and funnels them into wage labor on the estates or elsewhere, just as the first Green Revolution, and further diminishes their power. Researchers in Tanzania observe that “here are many beneficiaries of such GR interventions: input suppliers get guaranteed markets; service providers make a comfortable living; banks and financial institutions receive interest on loans…ut we have yet to understand what benefits farmers derive from these billions of dollars being spent” . Hopeful upfront investments made by smallholders have not proved lucrative; the promise of buyers for surpluses undelivered. As before, studies find that the most vulnerable populations have not staved off poverty and hunger through these approaches. Economic setbacks for small landholding farmers is no minor issue, as 80% of the land in Sub-Saharan Africa is cultivated by smallholders . The farming economies of SADC nations are unlike those of the United States and European Union, where agriculture consists of merely 0.9% and 1.6% percent of the GDP, respectively. Soft commodities make up 23.4%, 24.3%, 23.7%, and 28.6% of the total GDP of the SADC nations of Tanzania, Mozambique, Madagascar, and Malawi, for example . Farmers represent 78% of the workforce in Tanzania , where on just 0.5 to 2.0 hectares of land each, they produce 90% of the nation’s rice and maize . Matters which threaten smallholders carry dire implications for the entire structure of the economy, national stability, and the livelihoods of all citizens in these nations. Since new programs necessarily disrupt norms, they carry consequences, both foreseen and unforeseen.

It is therefore the duty of planners to reflect on a range of potential outcomes and discern which courses of action will likely accomplish the stated goals. It is understood that risks are associated with every innovation, but thorough considerations for history and context help minimize risks and avoid catastrophe. The failures in Malawi and Tanzania are the results of trial runs. Should the outcomes of the new Green Revolution in Africa continue to mimic those of its predecessor and become more widely adopted in fragile Southern and East African economies, the interventions could have deleterious effects, as the current agenda exacerbates hunger rather than neutralizes it and increases the financial burden on strained governments that are left to manage the purchase and dissemination of seed and technologies. Governments may also be forced to procure additional debt in the form of disaster relief loans if large percentages of arable land were to become allocated to a few cash crops that cannot secure profitable markets. As is documented in the overview of programs from 1940s-1980s, hunger relief campaigns historically centered on growing plantations of singular starches or legumes, and modern Monsanto and AGRA initiatives have followed suit. This has been the case without exception. Seed sold by distributers to smallholders consist of merely a few varietals which have, in many instances,hydroponic channel produced increased yields in the first generation. Starches include cassava, maize, or rice; and legumes include pigeon peas and soybeans. While techniques involving alternating harvests every few seasons to help fortify soils- rotating crops that fix nitrogen to the soil with crops that are nitrogen expensive – is sometimes encouraged by AGRA facilitators, enhancing yields through intercropping or alley cropping mutually-benefiting species on a shared plot cannot be practiced because heirloom crops and modified crops do not use the same inputs and pesticides. This means that farmers must approach adoption with an an ‘all or nothing’ principle. Therefore, smallholders who have converted all of their land for modified monocrops are left to manage a surplus for distribution, as opposed to an assortment of foodstuffs that includes crops for direct, familial or communal consumption. Plots that once produced groundnuts, cashews, sorghum, bananas, and preferred cassava and sweet potato varieties, for example, come to feature a modified starch or legume species in excess. In this arrangement, the aim is to unload one’s surplus in exchange for capital that can be used to purchase imports of supplementary food items that help achieve complete nutrition. This process is an exhaustively indirect solution to hunger, requires many risks of smallholders, and, in poor rural environments, is perhaps altogether inappropriate. Successful hunger alleviation using this method requires that each step be expertly executed and conditions ideal; for each is dependent upon climate conditions and power dynamics related to access, demand, and relative leverage in the global market. Each is unpredictable.

Alternatively, a modest surplus of local varietals can be more expediently sold in local markets, freeing smallholders of the burden of managing overproduced harvests and from reliance on dubious brokers over which they have limited influence. Importantly, dedicating only a small portion of one’s land to cash crops leaves space for subsistence agriculture, for which it would be premature to wholly abandon. Monocultural estates are claiming large swaths of fertile land that could otherwise be used for supplementary crops or grazing animals. It is obvious that a population cannot be satisfactorily feed on a diet consisting solely of modified maize or cassava. In the past, when populations have been forced into such diets due to prolonged extreme weather events or limited mobility and economic strife related to war, it has led to debilitating outbreaks of non-communicative dietary illnesses such as pellagra, kwashiorkor, and konzo, as well as death. Consuming a diet of high-yielding monocrops such as maize, which is among the most common genetically-modified species, cannot be legitimately argued to alleviate malnutrition. An effective food security campaign would include considerations for adequate dietary needs. Another implication of the adoption of modified seed is industrial agriculture. Fertilizers and pesticides used in industrial agriculture practices raise concerns regarding hazardous waste, namely polluted runoff in wells and municipal water systems near high-input farms. To manage this, wealthy and developed nations have tightly-operated structures and financial resources in place to mitigate harmful waste. Health and public safety issues caused by agrochemical seepage in public drinking water- which occurs frequently in GM maize and soybean-producing regions of the United States, such as Iowa and Missouri- are managed through filtration technologies to purify contaminated water and coordinated warning systems to notify the public and prevent consumption. Because consumption of nitrates inhibits the blood’s capacity to carry oxygen, results in birth defects, and can cause cancers and thyroid dysfunction, “he U.S. Environmental Protection Agency requires utilities to deliver tap water with no more than 10 milligrams of nitrates per liter” . The following examples will illustrate the enormity of the task of providing safe drinking water in intensive agricultural landscapes, and the substantial financial costs required to execute the task. The state of Iowa produces more corn than any other territory in the United States. Correspondingly, it is the second largest contributor of nitrate pollution in the Mississippi River Basin, and home to more than 200 communities routinely issued ‘Do Not Drink’ orders. Water in agricultural communities that use these approaches must be consistently monitored. On treating rivers and other freshwater sources from which people derive drinking water, Bill Stowe, general manager of Des Moines Water Works reports that “between 1995 and 2014, nitrate concentrations at his utility’s intakes on the Raccoon River exceeded the federal drinking-water standard on 1,635 days, or 24 percent of the time” . In 2015, local utility service spent $1.5 million to strip nitrates from the water, which required denitrification equipment such as ion exchange vessels priced at around $15 million USD . Wells are equally susceptible and harder to service. Nitrate levels as high as 168 ppm were found in private wells in rural Iowa and unsafe levels of nitrates were discovered in one-fifth of the 1,700 wells recently tested by the Iowa Department of Public Health . 1.5 billion gallons of contaminated water is treated annually in northeastern Missouri , where activated carbon powder is used to remove the atrazine, an herbicide used on GM maize fields that can hinder immune function . The district spends $130,000 USD per year removing atrazine alone . Utility services in the United States, which is almost completely converted to industrial agriculture techniques, spent $4.8 billion removing nitrates from public drinking water supplies in 2011 . This financial burden is often absorbed by those living in rural communities, who receive higher utility bills to offset the costs of sophisticated purification services . Unlike bacterial contamination, water polluted by industrial contaminates cannot be treated by boiling at home. Rural populations in the US rely on regular monitoring, action plans, and early warning systems to avoid illness. Warning systems include sensors and “automated event detection software” . Then contamination is confirmed using gas chromatography-mass spectrometry and other methods. Analysts alert agencies to issue ‘Do Not Drink’ orders that are relayed through wireless emergency text messaging, updates on utility and government websites, and news and media outlets. These protocols inform and empower populations so that they may make healthy choices and, despite the inconvenience, seek drinking water elsewhere. SADC nations, however, do not have the capacity to fund these types of purification utilities nor are rural areas equipped with qualified administrators and testing equipment to routinely monitor water sources, particularly following the defunding and dismantling of public service departments under structural adjustment.

Often, PGPR must be repeatedly added to a soil to maintain high population densities. One of the greatest research gaps limiting this field is inconsistent results when cultures are taken from lab to field. To better manage the ecosystem function of PGPR it is critical to study the survival and activity of both inoculated and native soil microorganisms in non-sterile soil.Carrier materials can influence inoculum success by providing protective habitats and also by affecting soil aggregate formation, which provide protection from predation . Soil inoculants are commonly prepared in formulations of powders, granules, and liquids . Previous research has evaluated the use of carrier materials to improve survival and distribution of inocula, much of which was conducted for soil inoculation with rhizobia . Peat moss is commonly used a microbial carrier and its benefits increase markedly if sterilized prior to inoculation . Vermiculite, lignite, and sodium alginate encapsulation have all been studied as alternative carriers to peat. Also,hydroponic gutter charcoal maintains high populations of inoculum suitable for use after 280 days of storage .

While this information has existed for years, very little work has been continued to examine the suitability of charcoal as a carrier for microorganisms.There is a variety of well-studied carrier materials, all of which have limitations that restrict their widespread use. For example, peat has had success in the rhizobia industry, but it is a highly variable material and the extraction of peat from bogs is unsustainable . The process of obtaining vermiculite also requires mining, which is associated with negative environmental impacts. As a result of limited sources, both peat and vermiculite are sometimes unavailable in regions where they are not naturally present . Alginate encapsulation of inoculum preparations offers a promising alternative to liquid inoculum, clay, and peat formulations. However, production of alginate beads is more expensive than the alternatives . Although the technology behind bioencapsulation has been reported since the 1980’s, the c rrent devices that prod ce the beads are still predominantly limited to lab-scale .Although countless studies have been performed on plant responses to soil inoculants, far less research has focused on inoculum preparation. A literature survey by Xavier et al.found that less than 0.5% of publications that cover rhizobia research discuss inoculum formulation. Many factors will differentially influence the survival of inoculum when applied to soils with diverse physical and chemical characteristics. For example, several abiotic soil parameters affected the survival of Azospirillum brasilense in bulk soil, including soil texture, water holding capacity, soil nitrogen, and organic matter . Accordingly, for PGPR to be considered a successful means to address major agricultural challenges, several things must be considered.

Carrier materials must be affordable, sustainable, and widely available. Also, the formulation of the inoculum must ensure that high PGPR populations can be stored and distributed into soils, and that once applied to soil, the PGPR can thrive, colonize roots, and commence plant-beneficial activities.Although biochar is a relatively new term to the scientific community, it is rooted in an ancient tradition of native Amazonians. Their method for disposing organic wastes involved heating it in deep earth pits, under low levels of oxygen. This left behind carbon rich “Terra Preta”, or black earth, which is still stable hundreds of years later and has proven to be an excellent soil amendment . Terra Preta soils contain high concentrations of nitrogen, phosphorus, potassium, calcium, and stable organic matter . These highly fertile pockets of soil are a stark contrast to the acidic indigenous soils, which are low in nutrients and organic matter and considered to be incapable of supporting agriculture . Interestingly, similar soil patches can be found throughout the world, and their high fertility is consistently associated with an abundance of black carbon . The use of charcoal also has a long history in agriculture and has been used to promote agronomic productivity for centuries . This tradition can be modernized by way of pyrolysis machinery specially engineered to heat solid or liquid biomass at designated temperatures in zero to low levels of oxygen. The resulting product has been termed biochar and biochar materials are receiving a lot of attention from scientists, engineers, farmers, and entrepreneurs .Given the current annual increase in atmospheric carbon dioxide of 4.1 tons year-1 , reduction of anthropogenic greenhouse gas emissions is critical .

Products of pyrolysis are carbonaceous and recalcitrant and can be incorporated into soils thereby serving as a stable carbon sink and climate change mitigation strategy . Biochars have been estimated to have mean residence times in soils of temperate climates of about 2000 years whereas fresh organic matter may be degraded in less than a decade . Pyrolyzing waste materials typically sequesters 50% of the source carbon as compared to traditional slash-and-burn techniques, which sequester only 3%, and natural decomposition, which retains 10– 15% . Biochar production has been credited as a tool that could offset 12% of anthropogenic carbon dioxide carbon equivalents annually if implemented on a global scale . Therefore, biochar production from all bio-wastes offers a sustainable mechanism for land and waste management while providing a carbon negative system.The process of pyrolysis generates porous, charred particles that structurally resemble the parent material but have carboxylated aromatic cores with slight negative charge . During pyrolysis a lack of oxygen available to the system results in a residual material rich in carbon. As pyrolysis temperatures are increased the resulting biochars become increasingly aromatic as oxygen-bound functional groups escape. NMR- based diagrams of slow and fast pyrolysis chars prepared with pyrolysis temperatures of 500°C, and gasification produced char generated at 750°C, display typical aromatic clusters that comprise biochar materials . Chen et al.used elemental analysis and FTIR to examine the sorption behavior of eight pine needle biochars produced at pyrolysis temperatures ranging from 100°C to 700°C. Pyrolysis temperatures up to 300°C mark the initial removal of OH, aliphatic C-O, and ester C=O groups from outer surfaces of such structures. At 400 ° C there is complete destruction of aliphatic alkyl and ester C=O groups that shield the aromatic core. At temperatures above 500 °C, there is further removal of aromatic COand phenolic –OH groups. The removal of these outer groups and exposure of the aromatic core is a key determinant of the sorption behavior and cation exchange capacity of the biochar . In general,u planting gutter for lignocellulosic materials, carbonization increases as combustion temperatures rise to 500°C and the materials approach full carbonization as temperatures reach 1000°C .The exposure of aromatic structures lends these biochars the property of having many fine pores. The abundance of nano to meso-sized pores contributes to the large surface areas associated with higher-temperature chars as well as to their enhanced ability to adsorb non-polar compounds . Biochar materials often retain the cellular structure of the feedstock, which can provide and intricate network of pores on the order of tens of micrometers in diameter . Hence, factors such as feedstock and pyrolysis conditions, the highest treatment temperature achieved during pyrolysis in particular, will affect the porosity, specific surface area, cation exchange capacity , and adsorptivity of the resulting biochar. This allows the opportunity to derive biochar materials with optimized properties for specific uses, such as agronomy, soil remediation, water filtration, or soil inoculum delivery. Meta-analyses of publications containing biochar field trials and greenhouse studies reveal that biochar application resulted in average increased above ground biomass ranging from a conservative 10% to 30% and a recent meta-analysis, which incorporated publications up to April, 2013 demonstrated an overall mean increase in crop productivity of approximately 11% with biochar application . From each of these meta-analyses it becomes apparent that biochar will have different effects on plant biomass and yield that is influenced by soil and biochar characteristics, application rate, crop variety, and time post amendment.

These reviews concur that biochar had the greatest positive influence on crop productivity when incorporated into acidic, clay, or sandy soils with low water holding capacity or low organic matter . The economic cost associated with biochar production and application has become a major limiting factor to its wide-spread use . Estimates by Brown et al.projected that current biochar production will only be profitable if bio-oil is simultaneously generated and carbon offsets have values in the range of 20 USD or more per metric ton. Shackley et al.provided a total assessment of the costs and benefits associated with biochar deployment and determined that biochar production costs are best reduced when feedstocks are waste feedstocks that would otherwise have a gate fee or landfill charge associated with their disposal. The greatest economic benefits associated with biochar use were related to energy production, as agronomic cost benefits can be highly inconsistent . Hence, adjustment to biochar products to ensure greater agronomic benefits could transition biochar use into a profitable sector. It is important to gain a fundamental understanding of how biochar application will affect soil biota before its use can be recommended on a broad scale. When applied to soils, biochar has many effects on soil physical and chemical properties that, in turn,affect the properties of the soil as a habitat for microbial growth. To date several exploratory studies have assessed the response of bacteria, fungi, and enzymes to biochar incorporation in a soil. In Figure 1.5, scanning electron micrographs depict clear images of fungal hyphae extending into biochar pores and bacterial cells located on char surfaces . Furthermore, microscopic, chromatographic, and spectroscopic studies have shown root hairs entering water-filled macropores or bonding to biochar surfaces . At this interface the biochar particles can adsorb organic compounds released from growing roots. Thus, biochar pores may serve as an ideal microenvironment for biological activity. However, contrary to these findings Quilliam et al.report minimal colonization of biochar by native soil microorganisms 3 years post 2– 4% amendment with a wood-derived biochar. In examining the influence of biochar on native soil bacteria many investigations have focused on diversity profiles. In a pioneering study, Kim et al.compared Terra Preta soils to adjacent pristine soils and found the Terra Preta to contain 25% greater bacterial species richness and hundreds of novel bacteria taxa . Also, Kolton et al.found that changes in bacterial community structures were observed after soils were amended with a fresh, citrus wood-derived biochar. Pyrosequencing of 16S rRNA genetic markers revealed a decrease in the total numbers of proteobacteria when biochar was added to a soil and an increase in bacteroidetes, and particularly flavobacteria . These are noted chitin degraders that secrete antifungal compounds. Nielsen et al.utilized an ultra high-throughput sequencing platform to obtain 16S rRNA gene sequences of bacteria with low abundance, as low as 0.01% of the total population. Their results agreed with previous findings, that biochar applications resulted in shifts in abundances of various taxonomic groups and also indicated that taxa correlation patterns are altered with biochar application . A phospholipid fatty acid analysis by Steinbeiss et al.revealed that once incorporated into soils, biochar prepared from a protein rich feedstock selected for fungi while biochar derived from a cellulose-based feedstock selected for bacteria. In agreement with this finding, another recent study demonstrated a positive correlation between the C:N ratio of biochar-amended soils and soil total PL A’s and bacterial PL A’s, in particular . However, Jindo et al.report a negative correlation between C:N ratio and bacterial biomass in biochar-compost mixtures. Additionally, biochar products, particularly those prepared at low pyrolysis temperatures, commonly contain a large number of adsorbed volatile organic compounds that may affect microbial growth and plant responses to biochar . Soil enzyme activities are differentially affected by biochar application . Most notably enzymes with enhanced activities in alkaline conditions showed higher activity post biochar amendment . This is reasonable, as pH’s of many biochars tend to be alkaline, a property that is dependent on pyrolysis temperature. Furthermore, Harter et al.used molecular techniques to assay abundance and expression of bacterial genes involved in nitrogen cycling as affected by biochar application. They found that N2O reductase transcript numbers were increased when soils were amended with 10% biochar . This altered microbial activity is especially important when considering greenhouse gas emissions and reduced N2O emissions from soil, a common phenomenon reported with biochar application .

The F3 peptide is a 31-amino acid fragment of the high mobility group protein HMG2N. F3 preferentially binds to nucleolin, a shuttle protein that is highly expressed on the plasma membranes of tumor cells.Nucleolin- targeted delivery of drug-loaded nanoparticles using F3 peptide or nucleolin-specific aptamers has been previously demonstrated.For example, F3-functionalized PEG-PLA nanoparticles led to deeper tumor penetration into 3D glioma spheroids and prolonged the survival of mouse bearing intracranial C6 glioma when loaded with paclitaxel.In this work, we conjugated F3 to TMVlys following an established protocol .In brief, TMVlys was mixed with a maleimidePEG4-NHS bifunctional linker using 10 equivalents linker per TMVlys coat protein in 10 mM KP buffer for 2 hrs. The mixture was then purified by ultra centrifugation at 112,000 g for 1 h on a 40% sucrose cushion. The F3 peptide synthesized with a C-terminal Cys was then added to the mixture at 0.5 equivalents peptide per TMVlys coat protein and reacted for 2 hrs. The final TMVlys-F3 was purified with 10,000 MW cut-off Slide-A-Lyzer MINI dialysis units. A higher excess of the F3 peptides led to aggregation and a lower excess did not show sufficient conjugation yields.

Cy5-labelled TMVlys-F3 was also prepared for cell uptake studies. Using the aforementioned protocol, SDS-NuPAGE gel electrophoresis confirmed covalent attachment of F3 peptides,bato bucket as indicated by higher molecular-weight bands The TMV coat protein has a molecular weight of ~17.5 kDa; a slightly higher molecular weight indicates the addition of F3 peptide . ImageJ software was used to quantify the degree of F3 conjugation, and data indicate that over 20% of the TMVlys coat proteins was modified with F3 peptide. The A260:A280 ratios of Cy5-TMVlys-F3 and Zn-Por:TMVlys-F3 were 1.21 and 1.29, respectively, which are indicative of intact TMV preparations . Furthermore, transmission electron microscopy indicated that TMVlys maintained its structural integrity post chemical modifications .To assess the targeting efficacy, we compared the cellular uptake of Cy5-labeled TMVlys and TMVlys-F3 particles using HeLa cells. HeLa cells were chosen because this cervical cancer cell line is known to express high levels of nucleolin.For cell targeting studies, HeLa cells were incubated with 150,000, 300,000, or 750,000 particles per cell at 37°C and 5% CO2 for 3 h in DMEM supplemented with 10% fetal bovine serum and 1% penicillin-streptomycin. Flow cytometry was performed as described above.

Flow cytometry showed an over 50% increase in cell uptake of conjugated Cy5-TMVlys-F3 particles . Compared to cells incubated with native TMV particles, the mean fluorescence intensity increased by 40-fold in the presence of nucleolin-targeted Cy5-TMVlys-F3 particles . Because flow cytometry does not provide insights into the fates of the nanoparticles, we also used confocal microscopy to study where the particles localized within the cells. HeLa cells were incubated with 6,000,000 particles per cell for 6 h in culture medium. Then cell membranes were stained with Alexa Fluor 555- conjugated wheat germ agglutinin and mounted with Fluoroshield™ with DAPI. Slides were imaged using a Leica TCS SPE confocal laser scanning microscope and the data was analyzed using ImageJ software. The confocal images were in agreement with flow cytometry, showing high cell interactions of the F3-targeted TMV formulation. The Cy5-TMVlys-F3 partiles appear bundled up at the surface of HeLa cells, where nucleolin is over expressed . Although others have shown intracellular trafficking of F3-functionalized polymeric nanoparticles,cellular uptake of Cy5-TMVlys-F3 was not observed in our study. This possibly indicates that the TMV’s high aspect ratio shape may not be suitable to be shuttled by nucleolin. Nevertheless, the accumulation of Cy5-TMVlys-F3 particles on the cell membrane may be advantageous for PDT as cell membrane targeting may prevent trapping of zinc porphyrin in endolysosomes and therefore enhance its cytotoxic efficacy. We moved on to explore the therapeutic efficacy of the F3-targeted Zn-Por drug delivery system. The enhanced cytotoxic efficacy of Zn-Por3+ loaded in TMVlys-F3 was reflected in the decreased survival of HeLa cells after white light treatment . TMVlys particles were loaded with 2,000:1 molar excess of Zn-Por3+ as described above prior to the conjugation of F3 peptides. From the MTT cell proliferation assay, the IC50 values for Zn-Por3+ in HeLa cells were equal to 0.034, 0.38 and 0.19 μM for Zn-Por3+ -TMVlys-F3, Zn-Por3+ -TMVlys and free Zn-Por3+ respectively. No cell killing was observed with drug-free TMVlys-F3 particles at maximum concentration.

Without light treatment, data indicated that Zn-Por3+ -TMVlys-F3 is non-toxic to HeLa cells . Compared to the data reported above, the efficacy of free Zn-Por3+ drug with white light treatment was 6-fold higher in B16F10 cells than in HeLa cells. This may be attributed to the biochemical differences between a mouse cell line and a human cell line. The drug activity decreased by half after loading into TMVlys-F3. This level of activity decrease after loading was not as significant as our previous data with TMV and TMGMV particles in B16F10 cells, yet the trend of decreased activity after loading into VNP did agree. Meanwhile, the targeted Zn-Por3+ -TMVlys-F3 particles showed a 5-fold increase in cell killing efficacy compared to the free drug. The increase PDT activity of Zn-Por3+ -TMVlys-F3 vs. Zn-Por3+ -TMVlys may be explained as follows: i) a significantly larger amount of particles targets cancer cells when using TMVlys-F3 vs. its native counterpart; and ii) TMVlys-F3 targets the cell membrane, light activation may lead to cell toxicity through cell membrane disruption, and iii) it is also possible that the PS cargo is released at the cell surface, and since the Zn-Por molecule is cell permeable and positive charged, cell uptake maybe favored – in contrast TMV without the F3 ligand accumulates in the endolysosomal compartment. In recent years, plant virus-based nanoparticles have been investigated for vaccine and immunotherapy applications to combat infectious diseases, cancers, and autoimmune diseases.Plant viruses are noninfectious to mammals and therefore are safter than their mammalian counterparts that are often used in oncolytic therapies.They can be manufactured in a cost effective manner and in large scales as viral nanoparticles as well as non-replicative viruslike particles devoid of their genomic payload.Cowpea mosaic virus VNPs and VLPs thereof have been proposed as in situ vaccine for cancer immunotherapy. The native form of CPMV consists of a bipartite ssRNA virus forming a 31 nm icosahedron with pseudo T = 3 symmetry. CPMV is made of 60 identical copies of a large and small coat proteins encapsidating RNA-1 and RNA-2 in separate but identical CPMV particles. When applied as in situ vaccine, the CPMV or eCPMV formulation is administered directly into a tumor to reprogram the tumor micro-environment and launch systemic anti-tumor immunity. While both CPMV and eCPMV demonstrated potent antitumor response in mouse models and canine patients,the RNA containing CPMV formulations demonstrated higher efficacy than eCPMV through the activation of additional cytokines and immune cells, which ultimately led to an extended survival rate of tumor-bearing mice.The proteinaceous nanoparticle presents danger signals that activate the immune system through pattern recognition receptors ,dutch bucket hydroponic and the presence of the RNA provides an additional danger signal.RNA activates TLR7/8, and induces type I IFN secretion, which increases the potency of the CPMV- based vaccines.This phenomenon was also reported using papaya mosaic virus as an in situ vaccine.While CPMV is not infectious to mammals, it remains infectious to legumes including Vigna unguiculataplants. From a translational point of view, it is thus important to develop RNA laden but non-infectious CPMV that is safe from to the environment and plants.

CPMV is stable in a variety of environmental conditions, such as temperature , pH , and in the presence of harsh chemicals, such as dimethyl sulfoxide.CPMV particles are not sensitive to certain standard methods of virus inactivation, including peptidase or hypochlorite treatment,but showed good response to ultra-violet light.Here we investigated UV treatment vs. chemical treatment of CPMV to render it non-infectious while maintaining its potent efficacy as a cancer immunotherapy. We compared β-propiolactone or formalin treatment with the previously reported UV inactivation method. These chemical treatment modalities are commonly used to produce non-virulent vaccines such as polio, hepatitis A, enterovirus, and influenza viruses vaccines.Of particular interests, these methods do not remove the RNA from the VNP, but rather create RNA damage preventing its transcription and translation, and therefore viral replication. UV light promotes RNA-protein crosslinking and dimerization of adjacent urcacils.βPL promotes the alkylation or acylation of cytidine, deoxyadenosine, and deoxyguanosine. βPL treatment also leads to a large extend of protein modifications; for example poliovirus proteins are more extensively modified by βPL than nucleic acid during viral inactivation.Specifically, βPL acylates and alkylates to a great extent cysteine, histidine, and methionine, and to a lesser extent with aspartic acid, glutamic acid, lysine, serine, threonine, and tyrosine.Lastly, formalin causes protein-protein and RNA-protein covalent crosslinking.To gain further insights into whether and to what degree RNA-protein crosslinking occurred, intact and denatured CPMV particles pre- and post-inactivation were analyzed by native gel electrophoresis and denatured samples were analyzed by SDS-PAGE. All gels were imaged after staining for proteins and nucleic acid under white light and UV light, respectively. In the native agarose GE, two distinctive protein bands were observed due to the presence of two electrophoretic forms of CPMV particles ; the fast form of CPMV is the result of a 24 amino acid loss at the C-terminus of the small coat protein due to proteolysis in plant cells.In all samples, nucleic acids and proteins traveled through the agarose gel together, confirming the entrapment of the RNA within the CPMV particles. CPMV treated with doses of 5, 7.5, 10 and 15 J cm-2 of UV showed signs of particle aggregation, as indicated by the presence of a smear instead of two distinct bands. Compared to CPMV, βPL-CPMV and Form-CPMV traveled farther through the gel proportionally to the concentration of βPL and formalin employed to inactivate CPMV. These results could reflect a change in overall particle charge due to the action of βPL and formalin on proteins and RNA. Samples were denatured by SDS-PAGE to separate the L and S coat protein subunits, visualized as single bands at 42 kDa and 24 kDa, respectively . The band intensity of UV-CPMV coat proteins decreased with increasing dose of UVradiation, indicative of the presence of particle aggregates. βPL-CPMV showed no sign of protein breakage or aggregation regardless of the dose of βPL used during treatment. In contrast, the higher the dose of formalin, the more inter-CP cross linking was observed at doses as low as 0.5 mM . GelRed staining was added to SDS-PAGE gels to assess the integrity of the RNA content of particles. RNA from UV-CPMV and Form-CPMV particles did not travel through the gel, most likely due to intra-RNA and RNA-coat protein cross linking; the samples remained stuck in the wells. RNA from βPL-CPMV matched the profile of that released from CPMV; however, at high βPL concentrations RNA breakage was observed – this is also consistent with UV/visible spectroscopy and SEC data as described above. Therefore, data indicate that at doses higher than 1 J cm-2 UV light or 1 mM βPL or formalin RNA and protein modifications and crosslinking occur; at high concentration of UV light, CPMV particle aggregation is observed; and at high βPL concentrations, RNA breakage is indicated. Agarose gel electrophoresis confirmed that leaves infected with CPMV inactivated through UV treatment at doses of 7.5 J cm- 2 or higher were indeed effectively inactivated and CPMV infection was not detectable by RTPCR . Similarly, formulations treated with 50 mM βPL-CPMV and 1 mM FormCPMV were confirmed to be fully inactivated. It is worth mentioning that leaves inoculated with 10 mM βPL-CPMV showed no visual symptoms of infection, yet these leaves tested positive by RT-PCR – the latter is a more sensitive assay. Based on the inactivation studies and infection assays in plants, for all subsequent experiments, we used the inactivated CPMV formulation obtained from 7.5 J cm-2 UV, 50 mM βPL, and 1 mM formalin. At these doses UV-CPMV was structurally intact but to some degree aggregated, and there was evidence of RNA-RNA and RNA-protein crosslinking. βPL-CPMV remained structurally sound and monodisperse but its RNA was severely damaged. FormCPMV also retained its size and monodispersity even though protein-protein, protein-RNA, and RNA-RNA cross linking occurred.

Bioavailability of CVTMGMV and free CV in C. elegans was investigated in liquid culture. C. elegans nematode motility was classified as either totally immobilized, impaired motility, or completely mobilized nematodes. To illustrate the data that was collected, a series of snap shots of C. elegans incubated with no treatment, 10 μM CV, and 10 μM CVTMGMV was taken every second for 60 seconds. The corresponding videos can be found in the supporting information. Figure 3.5 A-C illustrates the nematodes observed after 3 h of incubation. Five nematodes were selected in each treatment regime and pseudo-colored to illustrate their motility. Untreated C. elegans showed no impaired motility . For example, the nematode colored in pink moves across the frame within the 40 sec interval, while other nematodes disappear from or appear in the frame during that time interval. Although the motility of these nematodes is evident, most nematodes do not travel far but rather move within a restricted area,blueberry packaging such as the nematode colored in yellow. C. elegans treated with 10 μM of CV or 10 μM of CVTMGMV behaved differently and showed severe motility impairment .

All pseudo-colored nematodes in Figure 3.5 B+C were paralyzed or dead and did not move. However, this is not true for all nematodes, as a population of nematodes showed little to no motility impairment when treated with CV or CVTMGMV. From the imaging data there were no apparent differences between the two treatment groups, free drug vs. CVTMGMV .To quantitatively analyze the motility effects of CV on C. elegans, nematodes were treated with various concentrations of free CV, CVTMGMV, or TMGMV for 24 h at 22°C. At specific time points nematodes were observed under a white light microscope and the percent of affected nematodes and was quantified as a function of time. The effective concentration , defined as the concentration of CV at which half of the maximum immobilization of C. elegans was reached, was determined for free CV and CVTMGMV . Sixty percent of nematodes treated with 100 μM CV were paralyzed/dead within 1 h and no further improvements were observed within 24 h . When treated with 10 μM or 1 μM of CV, only ~30% or ~15% of nematodes were paralyzed/dead within the first hour, respectively. In those cases, maximum efficacy was observed after 6 h of incubation, when ~50% and ~25% of nematodes were affected. In both treatment regimes, a decrease in efficacy was observed after 6 h of incubation – this phenomenon may be explained because remaining unaffected population of nematodes continued to progress through their life cycle; consequently eggs were laid and nematodes hatched, which led to an overall increase in population and a decrease in percent of nematodes affected by the treatment. Furthermore, it is possible that at low doses of CV, nematodes are able to recover and slowly become mobile again.

At doses of CV lower than 1 μM, there was no significant effect on nematode motility compared to the untreated population. The EC50, defined as the concentration of CV at which half of the maximum immobilization of C. elegans was reached, was quantified at various time points and was determined to be 3.7 μM. CVTMGMV showed a similar trend to free CV , and, as expected, TMGMV alone did not show any nematicide properties When treated with 100 μM of CVTMGMV, ~40% of nematodes were paralyzed/dead within the first hour, and maximum efficacy was reached in the first 3 h. Therefore the efficacy of 100 μM of CV and CVTMGMV is identical after 3 h of incubation. However, when the concentration of CVTMGMV was dropped to 10 μM, the maximum efficacy was ~30% and was reached after ~8 h of incubation. Interestingly, CV release from CVTMGMV in nematode media conditions revealed a half-life of 8 h , thus supporting the idea that CV was released from TMGMV and made available to treat the nematode infestation. All studied concentrations of CVTMGMV lower than 10 μM led to no significant treatment of the nematode infestation compared to the untreated population. The calculated EC50 of CVTMGMV is 13.8 μM, which is approximately 4 times greater than the EC50 of free CV. While reduced efficacy was observed in the petri dish experiments, I envision that CVTMGMV will outperform free CV in the field based on the enhanced drug delivery aspect . Next, I set out to understand the bio-distribution of CV in the nematodes. I prepared fluorescently labeled TMGMV and analyzed whether TMGMV would interact with or be ingested by C. elegans.

Briefly, diazonium coupling and click chemistry was used to conjugate a Cy5 dye to TYR side chains on TMGMV, as structural studies indicated that TYR2 is solvent-exposed . I conjugated ~160 dyes per full length TMGMV, or about 7.5% of CPs were modified with Cy5 . We have previously demonstrated that a minimum conjugation of Cy5 to ~8% of TMV coat proteins is sufficient to yield maximum fluorescence intensity,237 thus the prepared samples were thought to be sufficient for imaging experiments. Fluorescent TYR-Cy5TMGMV was incubated with C. elegans nematodes for 3 h at 22°C and subsequently analyzed by fluorescent microscopy . Results indicate that nematodes ingest the proteinaceous TMGMV carrier and that while TMGMV distributes throughout the entire nematode body, the majority of TMGMV accumulates in the gastrointestinal tract. A soil mobility test was designed to establish the leaching of CVTMGMV and free CV in soil. Briefly, top soil was packed in a plastic column up to a height of 4 cm and saturated with deionized water. CVTMGMV or free CV was applied atop the soil columns, followed by DI water. Fractions were collected from the soil column, purified, and analyzed by UV/visible spectroscopy for the presence of TMGMV and CV. The λ260 and λ280 wavelengths were monitored to quantify the amount of TMGMV that leached through the soil. A background 260:280 absorbance was observed in a CV soil leaching column, which most likely corresponds to the absorbance of organic matter present in top soil . CVTMGMV showed enhanced mobility over free CV in the soil column,blueberry packaging box eluting from the column at high concentrations in the 5th to 15th elution fractions . In stark contrast, the efflux of CV from the soil column was delayed until the 25th to 50th elution fractions at a concentration 3.6 times lower than CVTMGMV . CV is hydrophobic and has a strong binding affinity to soil particles rendering the drug mostly immobile in soil, which explains the delayed efflux and lower concentrations eluted. Taken together, the data demonstrates the potential of TMGMV as a drug carrier to enable penetration of CV or other nematicides through soil to reach nematodes feeding on the roots of plants. In this study, I have demonstrated the potential of tobacco mild green mosaic virus as a carrier for anthelmintic drugs, such as crystal violet , to treat plants infected with parasitic nematodes. After careful analysis of the TMGMV structure, I identified solvent exposed TYR2 on the exterior surface enabling chemical modification. I also identified solvent exposed carboxylates, GLU145 and ASP66 on the exterior surface and GLU95 and GLU106 on the interior surface, and established the chemical addressability of these residues. I also showed the potential for electrostatic encapsulation of positively charged guest molecules in TMGMV. Further studies are needed to identify which of the identified GLU and ASP residues are chemically reactive. Electrostatic drug loading using crystal violet was achieved, yielding TMGMV carriers loaded with ~1500 CV per CVTMGMV nanocarrier.

Treatment efficacy, while lower compared to free drug, was demonstrated using liquid C. elegans nematode cultures . Diffusion experiments revealed significantly increased soil mobility of CVTMGMV vs. free CV; the latter was unable to sufficiently diffuse and disperse through soil. Overall CVTMGMV demonstrates efficacy and superior soil motility, and as such makes a promising platform technology as a drug carrier targeting agricultural application. Pesticides are needed to protect our crops and thus maximize crop yields.However, the efficacy of chemical pesticides is limited by their instability and strong binding to organic matter in soil, which can render them inactive or prevent their accumulation at the root level, where many pests reside.Large doses are applied to compensate, resulting in the accumulation of pesticide residues in soil, water and agricultural products.Long-term exposure to these chemicals is a risk to human health and threatens the biodiversity of an already fragile ecosystem.Advances in nanotechnology have led to the development of more effective drug delivery and medical imaging methods , and the same innovations are now being applied to smart agrochemical delivery systems, known as nanopesticides.These involve the use of nanomaterials for the adsorption, encapsulation or conjugation of pesticides, improving the biodegradability, stability, permeability and dispersion of the active pesticide ingredient. Nanopesticides have a much greater surface area than conventional pesticides, increasing their potential for interaction with target pests at lower doses. The encapsulation of pesticides within nanoparticles also prevents premature degradation and the risk of direct human exposure to the active ingredient. There is also evidence that nanopesticides and conventional pesticides differ in their environmental behaviour, so it is necessary to understand the fate of nanopesticides in detail in order to ensure they comply with regulatory guidelines and legislation.Most of the nanopesticides investigated thus far are based on synthetic or natural polymers, metallic compounds or liposomes, which tend to persist in the environment.As a biodegradable alternative, nanopesticides can be developed from plant viruses.One example, already EPA-approved, is the application of Tobacco mild green mosaic virus as the herbicide Solvinix, which is produced by BioProdex for deployment against invasive tropical soda apple weed in the state of Florida.The safety profile and possible risks of TMGMV have been reported.TMGMV cannot self-disseminate and is not transmitted by vectors such as insects, seeds, or pollen. Mechanical transmission through insects or contact between plants is thus the only route of transmission. Only plants of the Solanaceae are susceptible to TMGMV infections. Therefore, TMGMV offers a good safety profile for crops that are not part of the Solanaceae. Nonetheless, TMGMV as well as other plant virus-based systems could be inactivated through ultraviolet radiation for safe use on any crop.To investigate the potential of plant virus nanoparticles and virus-like particles as nanopesticides in more detail, I compared the behaviour of three viruses and two synthetic particle formulations in soil column experiments and computational models, as a way to gauge their ability to deliver pesticides to the rhizosphere and thus prevent infestation by root pests . I tested two VNPs, based on the rod-like TMGMV and the icosahedral Cowpea mosaic virus , and a virus-like particle based on Physalis mosaic virus . These were compared to mesoporous silica nanoparticles and a poly formulation , which have already been developed as synthetic nanopesticides.TMGMV was oβtained from Bioprodex, DegraFluorex Fluorescent PLGA nanoparticles were purchased from Phosphorex, and MSNPs functionalized with propylcarboxylic acids were obtained from Sigma-Aldrich. I resuspended 3 mg ml-1 of PLGA and 1 mg ml-1 of MSNP in distilled water and sonicated them using a Branson 2800 device for 10 min to obtain homogeneous solutions. CPMV was propagated in Burpee black-eyed pea plants and purified as previously described.PhMV VLPs were prepared in ClearColi BL21 cells as previously described.USDA Permits were obtained for any work with plant viruses. TMGMV comprises 2,130 identical coat proteins arranged helically around a single-stranded RNA genome, forming a hollow rigid rod measuring 300 × 18 nm with a 4-nm internal channel.The external surface features two solvent-exposed tyrosine side chains , which can be functionalized using diazonium coupling reactions. I used sulfo-Cy5-azide to modify these Tyr residues as previously described.10 Briefly, I mixed 25 μl 0.68 M 3-ethynylaniline with 75 µl 3 M sodium nitrite in 400 μl 0.3 M p-toluenesulfonic acid monohydrate for 1 h on ice. I then added 15 equivalents of the resulting diazonium salt to 2 mg ml-1 TMGMV in 10 mM borate buffer for 30 min on ice. The particles were centrifuged at 112,000 g for 1 h on a 30% sucrose cushion to separate the TMGMV-alkyne particles from the excess DS. TMGMV-alkyne was resuspended in 10 mM KP buffer overnight before adding sulfo-Cy5-azide via a Cu-catalysed alkyne-azide cyclo-addition reaction. I added two equivalents of Cy5 per coat protein to 2 mg ml-1 TMGMV-alkyne in the presence of 2 mM aminoguanidine, 2 mM L-ascorbic acid sodium salt and 1 mM copper sulfate in 10 mM KP buffer on ice for 30 min.

The reduced bio-degradation in the SB microcosms may have resulted from the ~40% higher carbon content in the SB microcosms, which would be expected to increase the soil-water distribution coefficient by a comparable amount. Reduced TCS concentration in soil pore water would be expected to slow bio-transformation, potentially in a nonlinear fashion. Another possible contributor to the slower degradation of TCS in SB is the greater availability of alternative, likely more easily degradable, carbon sources in SB than soil microcosms, reducing the use of TCS as a substrate. Selective bio-degradation of one carbon source, and inhibition of the degradation of other chemicals also present, has been observed for mixtures of chemicals in aquifers . To assess which of these mechanisms was controlling, measured Freundlich isotherm parameters for TCS adsorption on bio-solid amended Yolo soil were used to calculate equilibrium pore water concentrations in the soil and SB microcosms over the course of the experiment. Using estimated pore water concentrations of moistened soil and SB samples,pe grow bag instead of total soil concentrations to perform half-life calculations, resulted in modest increases in the rate constants and decreases in half-lives of soil samples and did not narrow the significant gap between half lives in soil and SB .

This suggests that the primary reason for the slower degradation of TCS in bio-solid amended soils is the increase in more labile forms of carbon because organic material is highly porous and has a lower particle density. Previous research shows that TCS biodegrades within weeks to months in aerobic soils , although Chenxi et al., found no TCS degradation in bio-solids stored under aerobic or anaerobic conditions, Kinney et al., observed a 40% decrease in TCS concentrations over a 4-month period following an agricultural bio-solids application. Because the slopes of the lines in Fig. 1 are not significantly different as a function of spiking level , the slopes were averaged for each treatment type, yielding apparent first order rate constants of 0.093±4% d−1 for soil samples and 0.024±41% d−1 for SB samples where the percent error represents the relative percent difference between the 10 mg/kg and 50 mg/kg degradation curves. These apparent rate constants translate to half-life estimates of 7.5 d in soils and 29 d in bio-solid amended soil. The estimated half-life of TCS in soil is within the range of previously reported half-lives of from 2.5 to 58 d in soil . The half-life determined here in bio-solid amended soils is lower than the one available literature value of 107.4 d . The microbial biomass decreased in the TCS spiked samples after 7 or 30 days of incubation in comparison with the unspiked controls, for both soil and SB, and the decline was statistically significant at 50 mg/kg .

Although exposure to TCS caused declines in biomass in both soil and SB microcosms, the total microbial biomass was two times higher in SB than soil probably due to the increased availability of nutrients and/or possibly due to addition of bio-solid associated microorganisms in the latter . The total number of PLFAs ranged from 42–47 in soil and 48–59 in SB . No significant change in numbers of PLFAs was evident with increasing dosage of TCS for any incubation time suggesting that TCS addition did not adversely affect microbial diversity. Microbes respond to various stresses by modifying cell membranes, for example by transforming the cis double bond of 16:1ω7c to cy17:0, which is more stable and not easily metabolized by the bacteria, reducing the impact of environmental stressors . Consequently, the ratio of cy17 to its precursor has been employed as an indicator of microbial stress that has been associated with slow growth of microorganisms . Increases in this stress biomarker were observed in both soil and SB samples as TCS concentrations increased , suggesting that TCS has a negative effect on the growth of soil microorganisms. The overall level of cy17 to its precursor is lower in SB than soil samples, suggesting that nutrients contributed by the bio-solids reduce stress on the microbial community. Our study agreed with a previous study showed that carbon added to soil led to a reduction in the cy17 fatty acid TCS additions, however, increased the stress marker compared with that detected in the corresponding samples with no added TCS.

A broader implication of this result is that presence of bio-solids may mitigate the toxic effects of chemicals in soil, or chemicals added in combination with bio-solids, on soil microbial communities. Groupings of microbial communities, based on CCA analysis of their composition as estimated by PLFA, were distinguished primarily by whether they were in soil or SB treatments and secondarily by time since spiking . To isolate the effects of bio-solids and TCS amendments on microbial community composition, the data was analyzed using pCCA considering TCS and bio-solid amendment as environmental variables, and incubation time as a covariable . This confirmed the results of the CCA indicating that the strongest determinant of microbial community composition was addition of bio-solids to soil. TCS concentration, on the second axis, described only 3.6% of the variation, showing TCS effects were overshadowed by the effects of bio-solid amendment. Bio-solid amendments caused an approximately two-fold increase in PLFA biomarkers for Gram-positive bacteria, actinomycetes and eukaryotes in SB compared to soil samples . Even larger increases were observed in biomarkers for fungi and Gram-negative bacteria, which were up to three times higher in SB than soil. Again, these changes were likely due to increased nutrient availability in the bio-solid amended samples and/or the biomass added along with the bio-solids, growing bags consistent with previous studies that found that the fatty acid 18:2 ω6, 9c and monounsaturates were increased by addition of these materials . The effect of TCS on microbial community composition was greater in soil than SB. Spiking with 10 or 50 mg/kg TCS decreased the abundance of Gram positive and Gram negative bacteria as well as fungi, with reductions ranging from 14 to 27% by day 30. Additionally, actinomycetes, which are Gram positive bacteria, were reduced in the 50 mg/kg TCS samples after 30 days of incubation . Eukaryotes were negatively affected after 7 and 30 days of incubation at both concentrations of TCS in soil but not SB samples. Biomass results for all microbial groups were consistent in suggesting that the presence of bio-solids mitigated the potential toxicity of TCS. It is important to note that the spiking levels used here are similar to levels found in the upper half of U.S. bio-solids, but would be unlikely to be achieved in bio-solid amended soils even after continued long term application. Therefore, the effects observed at the 10 or 50 mg/kg spiking levels should be viewed as a conservative upper bound on potential effects expected in the field. In addition, since all of the results in this study are based on an observation period of 30 d, the extent to which the observed effects persist is not known. Future studies should, in particular, investigate longer term changes in community structure in response to addition of bio-solids both with and without specific contaminants.

Over the past 30 years, nanoparticle engineering has led to the development of novel delivery systems for active ingredients with medical, veterinary, and agricultural applications. The increasing cost of research and development combined with the growing number of competitive manufacturing entities, short patent cycles, and the tightening regulatory guidelines for active ingredients, have made it difficult to bring new formulations from the bench to the market.Furthermore, the efficacy of many drugs is limited by their low solubility and/or stability, as well as off-target effects following systemic delivery. For example, cancer therapy is often unsuccessful due to the toxicity of cancer drugs towards healthy cells and/or the development of resistant cells over expressing efflux transporters and multi-drug-resistance proteins.The resulting low bio-availability of the active ingredient in the tumor requires the administration of larger doses to ensure the drug concentration stays within the therapeutic window, which in turn increases off target toxicity. Nanocarriers can address this challenge by delivering active ingredients via the enhanced permeability and retention effect, a well-established phenomenon based on the combination of leaky vasculature and poor lymphatic drainage at the tumor site.The EPR effect only increases the tumor homing of nanoparticles by two-fold compared to normal tissue,so nanoparticles can also be functionalized with targeting ligands, aptamers, antibodies, or antibody fragments to promote their binding to receptors overexpressed on tumor cells or in the surrounding extracellular matrix.The entrapment of active ingredients in nanocarriers also reduces the clearance rate via renal elimination and phagocytosis, which increases the active ingredient circulation time and therefore its therapeutic longevity. The medical and veterinary applications of nanocarriers are analogous, but only experimental veterinary applications have been reported.Most research in veterinary drug delivery has focused on diseases in animals that can be translated to humans. However, the importance of animal welfare per se is increasingly important to consumers, and nanocarriers that improve the efficacy and safety of active ingredients are demanded in the context of companion animals such as cats, dogs and horses, as well as farm animals such cattle, sheep, swine and poultry.Pet owners consider companion animals as an extension of the family and are willing to pay their bills, including the high cost of cancer treatment, with the cost of veterinary care in the USA therefore rising from $7 billion in 2001 to $19 billion in 2019.This increase most likely reflects a combination of inflation, high drug costs, better treatment options , and an increased willingness to care for pets. In contrast, the food industry works with low profit margins and would only treat animals suffering from temporary and low-risk diseases, such as infections.Veterinary nanocarriers must therefore combine low costs with the release of active ingredients for sustained periods to minimize the frequency of animal handling and improve therapeutic efficacy. For example, animals are often subject to bacterial infections, and a nanomedicine approach could achieve the targeted delivery of drugs to pathogens, killing them on demand. This avoids the unnecessary use of antibiotics, which can encourage the emergence of resistant strains. The controlled delivery of agrochemicals and nutrients to plants is conceptually similar to drug delivery in humans and animals. However, agricultural delivery takes place in an open field, with variable weather and geographic features and no specific transport pathway to the target, in contrast to the closed and regulated nature of the bloodstream. Nanocarriers can be administered via the foliage, where they are taken up passively through stomata and any wounds, or can be transported through the soil and taken up via the roots.Among the agrochemicals that can be delivered using nanoparticles, pesticides are particularly suitable candidates because they are effective at very low doses but are difficult to apply in such small amounts due to their non-uniform distribution in the field.To compensate, the active ingredient can be diluted within a mixture of liquid or solid diluents. However, the active ingredient is often unstable, sparingly soluble, and binds with high affinity to soil particles, thus reducing its efficacy against target pests and increasing the amount required to achieve an effective dose.In an analogous manner to the off-target effects caused by systemic drugs, the persistence of large quantities of pesticides in the environment is toxic to other species, and contaminates the soil and groundwater leading to health problems in domestic animals and humans, including cancer and infertility.In one strategy, the active ingredient is enveloped in organic or inorganic coatings for protection against photolysis or bio-degradation, allowing the controlled release of the ingredient.But even microencapsulation is limited by the poor chemical and thermal stability of the capsules, and degradation promotes the acidification of soil, which can impair its fertility. As discussed in more detail below, these drawbacks can be addressed by a new generation of nanocarriers based on polymers, lipids and other materials. The definition of a nanomaterial is not yet harmonized, but the International Organization for Standardization defines nanoparticles as objects with dimensions of 1–100 nm, because the physicochemical properties of the material at this scale differ from the bulk material. Unfortunately, this ISO definition excludes most nanomaterials that are relevant in the medical, veterinary, and agricultural sectors.