Horticulture

Dutta et al. found similar re-aeration patterns in a 1 m column experiment in a sand dominated soil, with re-aeration occurring quickly once drying commenced. Even with the presence of a limiting layer, defined by lower pore gas velocities and higher carbon concentration, a sandy loam channel acted as a conduit of O2 into the deep vadose zone maintaining a relatively oxic state and thus decreasing the ability of the vadose zone to denitrify. In systems with higher DOC loadings to the subsurface, oxygen consumption may proceed at higher rates creating sub-oxic conditions in the recharge water and more readily create reducing conditions favorable to denitrification in the subsurface . We note here that microbial growth, which was not modeled in this study, could also affect the rates of O2 consumption and re-aeration, which could lead to underestimation of O2 consumption . Overall, denitrification capacity across different lithologies was shown to depend on the tight coupling between transport,square flower bucket biotic reactions as well as the cycling of Fe and S through chemolithoautotrophic pathways. Under large hydraulic loadings , overall denitrification was estimated to be the greatest as compared to the lower hydraulic loading scenarios .

The main reason for the higher denitrification capacity was the significant decline in O2 concentration estimated for this scenario, whereas such conditions could not be maintained below one meter with lower hydraulic loadings under scenarios S2 and S3. However, nitrate was also transported deeper into the column under S1 as compared to S2 or S3. Tomasek et al. found the reverse in a floodplain setting, where intermittent indundation with flood water, comparable to our S2 and S3 contexts, resulted in higher rates of denitrification in the zone that was always inundated, due to priming of the microbial community and pulse releases of substrates and electron donors. Future studies examining the impact of AgMAR on denitrification should include processes such as mineralization to see if the same behavior would be observed. It seems that there may exist a threshold hydraulic loading and frequency of application that could result in anoxic conditions and therefore promote denitrification within the vadose zone for different stratigraphic configurations, although this was not further explored in this study. In another study, Schmidt et al. found a threshold infiltration rate of 0.7 m d-1 for a three hectare recharge pond located in the Pajaro Valley of central coastal California, such that no denitrification occurred when this threshold was reached. For our simulations, we used a fixed, average infiltration rate of 0.17 cm hr-1 for our all-at-once and incremental AgMAR scenarios, however, application rates can be expected to be more varied under natural field settings. Our results further indicate that the all-at-once higher hydraulic loading, in addition to causing increased levels of saturation and decrease in O2, resulted in leaching of DOC to greater depths in comparison to lower, incremental hydraulic loading scenarios .

Akhavan et al. 2013 found similar results for an infiltration basin wherein 1.4% higher DOC levels were reported at depths down to 4 m when hydraulic loading was increased. Because organic carbon is typically limited to top 1 m in soils , leached DOC that has not been microbially processed could be an important source of electron donors for denitrification at depth. Systems that are already rich in DOC within the subsurface are likely to be more effective in denitrifying, and thus attenuating, NO3 – , such as floodplains, reactive barriers in MAR settings, or potentially, organically managed agroecosystems .This finding can also be exploited in agricultural soils by using cover crop and other management practices that increase soluble carbon at depth and therefore remove residual N from the vadose zone . While lower denitrification capacity was estimated for scenarios S2 and S3, an advantage of incremental application was that NO3 – concentration was not transported to greater depths. Thus, higher NO3 – concentration was confined to the root zone. If NO3 – under these scenarios stays closer to the surface, where microbial biomass is higher, and where roots, especially in deep rooted perennial systems such as almonds, can access it, it could ultimately lead to less NO3 – lost to groundwater. While there is potential for redistribution of this NO3 – via wetting and drying cycles, future modeling studies should explore multi-year AgMAR management strategies combined with root dynamics to understand N cycling and loading to groundwater under long-term AgMAR. Simulation results indicate that wetter antecedent moisture conditions promote water and NO3 – to move deeper into the domain compared to the drier base case simulation.

This finding has been noted previously in the literature, however, disagreement exists on the magnitude and extent to which antecedent moisture conditions affect water and solute movement and is highly dependent on vadose zone characteristics. For example, in systems dominated by macropore flow, higher antecedent soil moisture increased the depth to which water and solutes were transported . In a soil with textural contrast, where hydraulic conductivity between the topsoil and subsoil decreases sharply, drier antecedent moisture conditions caused water to move faster and deeper into the profile compared to wetter antecedent moisture conditions . In our system, where a low-permeability layer lies above a high permeability layer , the reverse trend was observed. Thus, a tight coupling of stratigraphic heterogeneity and antecedent moisture conditions interact to affect both NO3 – transport and cycling in the vadose zone, which should be considered while designing AgMAR management strategies to reduce NO3 – contamination of groundwater. Furthermore, dry and wet cycles affect other aspects of the N cycle that were not included in this study . Specifically, the effect of flood water application frequency on mineralization of organic N to inorganic forms should be investigated to assess the full N loading amount to groundwater under AgMAR. Pyrethroids are the most commonly utilized residential insecticides partly due to the generally held belief that they pose minimal risk to human health. In addition, there are numerous worldwide applications for pyrethroids in agriculture, horticulture, public health and textiles . They have insecticidal activity in their parent form and donot require metabolic activation to exert their neurotoxic effects, which are mediated by increased open time of voltage-gated sodium channels . The initial symptoms of acute occupational pyrethroid intoxication include parasthesia consisting of burning and itching sensations on the skin or dizziness that develops approximately 4–6 h after exposure,black flower bucket although dermal symptoms can manifest after minutes of application. Systemic symptoms can occur up to 48 h after acute exposure . Pyrethroids are classified as Type I or Type II pyrethroids. Type I pyrethroids are esters of primary or secondary alcohols, whereas Type II pyrethroids are esters of secondary alcohols with a cyano group at the  -carbon of the alcohol component. The acid andalcohol moieties both contain chiral centers, leading to the possibility of several stereoisomers for each pyrethroid, which may exhibit isomer-specific insecticidal activity . The type II pyrethroid,  CM, is derived from the 8- stereoisomers that comprise the pyrethroid cypermethrin, which is one of the most common pyrethroids in agricultural and residential use.  CM is a racemate of two cypermethrin stereoisomers: – -cyano-3-phenoxybenzyl–cis-3–2,2-dimethylcyclopropane carboxylate, and – -cyano-3-phenoxybenzyl–cis-3– 2,2-dimethylcyclopropane carboxylate , which are considered the two most stable cis-isomers . The major detoxification pathway of  CM is through hydrolysis by esterases and hydroxylation by cytochrome P450s . In vitro studies have shown that alcohol and aldehyde dehydrogenases can also contribute to the metabolism of pyrethroids . Dosing studies with  CM and cypermethrin in 6 human volunteers indicate an elimination half-life range of 8–22 h for a single dermal exposure . The assessment of human exposure to insecticides such as pyrethroids is often based on quantification of metabolites excreted in urine . The major urinary metabolites of  CM in humans are 3-phenoxybenzoic acid and cis-3–2,2-dimethylcyclopropane carboxylic acid , which are conjugated prior to being excreted in the urine .

3-PBA is a metabolite common to a large number of pyrethroid insecticides, while cisDCCA is a more specific metabolite and useful urinary biomarker of exposure for  CM, permethrin and cyfluthrin . Thus, urinary concentrations of 3-PBA may serve as a general biomarker of pyrethroid exposure, while cisDCCA represents a more specific biomarker for human exposure to  CM. Currently, there are no published studies specifically assessing the occupational exposure to  CM. One pyrethroid study investigated occupational exposure in Chinese cotton workers spraying deltamethrin, fenvalerate and a deltamethrin methamidophos mixture . Hardt and Angerer evaluated occupational exposure in individual workers after applying a mixture of up to 7 synthetic pyrethroids, including  CM. Another study described occupational exposure to permethrin and fenvalerate , and a number of other studies have documented general pyrethroid exposure in non-occupational settings utilizing 3-PBA as a general biomarker of pyrethroid exposure . The primary objective of the present study was to investigate occupational exposure to CM by quantitating the daily urinary levels of cis-DCCA and 3-PBA before, during, and after the application of CM in a cohort of Egyptian agriculture workers who were spraying  CM on cotton fields daily for up to 10 consecutive days. A biomonitoring study on a subset ofthis Egyptian agriculture worker population determined that 94–96% of the dose was due to dermal exposure . While chlorpyrifos exposure has previously been characterized in these individuals , this is the first study to describe a longitudinal assessment of exposure to  CM.A detailed description of the study setting was previously published , and a previous chlorpyrifos bio-monitoring study on a subset of this Egyptian agriculture worker population estimated that 94–96% of the dose was due to dermal exposure . Briefly, the present study was conducted in Menoufia, one of 29 governorates in Egypt, which is located in the Nile River Delta north of Cairo. Daily urine samples were collected from a cohort of 37 Ministry of Agriculture workers which were divided into three job categories: applicators who spray the insecticide on the cotton crop with a backpack mistblower sprayer; technicians who walk the fields with the applicator in order to point out particular areas which need attention; and engineers who direct the work mainly from the edge of the field. These workers were assigned to 3 regions where  CM was sprayed daily in 3–5 h work shifts for up to 10 consecutive days in the summer of 2008. The workers provided daily spot urine samples before, during, and after the insecticide application cycle. The urine samples used for analysis were collected just prior to start of the work day, on 24 h intervals at approximately 3 pm. One technician was included in the demographic analysis, but did not provide any urine specimens during the pyrethroid application and was therefore excluded from the current study. Samples were placed on wet ice in a cooler and transported to Menoufia University , where they were stored at −20 ◦C until being shipped to the State University of New York at Buffalo on dry ice for analysis. Creatinine concentrations were measured using the Jaffe reaction ; urinary cis-DCCA and 3- PBA concentrations are expressed as micrograms or nanomoles per gram creatinine. All protocols and questionnaires were approved by Institutional Review Boards of Menoufia University and Oregon Health & Science University, the institute administering the parent grant that funded the field studies.The Type II pyrethroid CM is metabolized by hydrolytic cleavage of the ester bond to form the metabolite cis-DCCA, while the alcohol moiety is further metabolized to 3-PBA likely by oxidative enzymes such as cytochrome P450s and aldehyde dehydrogenase . Urinary levels of cis-DCCA and 3-PBA were measured in the Egyptian cotton field worker to estimate their exposure to  CM over the course of the spray schedule . The results show great variability from worker to worker, even within the same job category. The 3 field stations demonstrate 3 distinct exposure scenarios, including different length of spray period and peak metabolite levels during the application. Accordingly, not all applicators were highly exposed, while several individual engineers and technicians were highly exposed. To our knowledge this is first study to conduct a longitudinal assessment of occupational human exposure specifically to  CM. This cohort is unique because the workers were applying a single pesticide for up to 10 consecutive days. Similar to the previously reported occupational exposure to chlorpyrifos exposure in this cohort , applicators had the highest levels of urinary metabolites and thus greater exposure to the parent compound, while technicians and engineers had lower exposures.

These processes took place in tandem with the erection of an overarching global apparatus, in particular the United Nations system and the Bretton-Wood institutions . Early rapprochements between the dozens of newly independent nation-states unfolded largely under the auspices of – and were in a sense enabled by – this multilateral governance system. In particular, the United Nation’s “one nation, one vote” rule quickly became an appealing invitation for the multitude of new nations, large and small, to band together around issues of common concern, or to make strategic alliances in the pursuit of their interests. In the mid-sixties, the Group of 77 emerged as the most prominent face of the Southern bloc, in the ambit of the UN Conference on Trade and Development . This time, Asian, Middle-Eastern and African countries were joined by most of their Latin American counterparts , and commercial interests came to the fore as a common thread in negotiations with the developed world. Indeed, the G-77 – which is still in place and, despite the maintenance of its original name,flower bucket assembles today over 130 developing countries – is one of the fora where shared principles of South-South cooperation are being currently put forward .

The multilateral system is however far from a neutral space; it carries the imprint of the post-war geopolitical weight of Western and Eastern powers, most notably in the asymmetry between the United Nation’s General Assembly and its highest decision-making body, the Security Council. The U.S. and Europe further entrenched their hegemony through the Bretton Woods institutions, where voting power is weighted according to each country’s financial contributions . Two decades ago, the fall of the Eastern bloc provoked a seismic geopolitical shift in this post-war configuration, whereby the West collapsed into the North, and the Second and the Third Worlds were aggregated under the umbrella category of the “global South”. The international governance structure crystallized in the aftermath of the World Wars remained nonetheless fundamentally unaltered, thus becoming a fundamental battleground for contemporary North-South disputes, according to which South-South alliances are being currently revitalized and rearranged. According to both the literature and my field interlocutors, this is the single strongest drive behind Brazil’s recent South-South cooperation spur, which was triggered and is largely driven by foreign policy.Brazil’s standpoint as an emerging donor also brings to the fore other, more recent global battlegrounds.

After a period of general retraction in South-South relations during the eighties and nineties ,as the twentieth century came to a close they gained new impetus and complexity with the emergence of global regulatory apparatuses in sectors such as trade, environment, finance, and intellectual property. In particular, negotiation rounds on trade and the environment have been marked by successive standoffs credited to seemingly intractable divergences across the North-South divide, for instance over opening up developed countries’ markets to agricultural exports from the developing world. Although far from new, these struggles came to occupy center stage in recent World Trade Organization negotiations, causing a stalemate in the Doha Round that began in 2001 and remains in place. Some have even singled out the 2003 WTO meetings in Cancun as a landmark for the revamping of South-South engagements in the last decade . Indeed, this has been a major battleground for Brazil, which recently succeeded in having its ambassador to the WTO, Roberto Azevedo, elected as the organization’s director general. Several of my interlocutors attributed to Brazil’s South-South cooperation efforts the support many African countries and others granted to Azevedo’s bid, as well as to José Graziano in the Food and Agriculture Organization before him. Like its predecessors in Bandung and the Non-Aligned Movement, however, concerted action across the global South in these arenas has worked only up to a point. This ensemble of countries is far from homogeneous, and they have collaborated as much as competed with each other – the case of Brazil and Africa will be dealt with in the next two chapters.

The global South, therefore, can only be a provisional assemblage established in relation to an equally constructed global North. Yet, Southern countries have sought to sustain some appearance of unity at least at the level of discursive principles. Many passages in this document are remarkably reminiscent of the Bandung language of solidarity, collective self-reliance, and mutual respect for each other’s sovereignty – which was, on its turn, inspired by earlier bilateral relations.Its emissary is a monolithic and homogeneous South addressing an equally monolithic North, and although there is talk of complementarities between South-South cooperation and North-South development, the relationship is largely constructed in terms of difference. The main difference is in character: South-South cooperation is supposed to be based on “expressions of solidarity and cooperation borne out of shared experiences and sympathies” that, one is led to infer, are not shared by the North. But this supposed difference in character has an important procedural side: South-South cooperation should have its own agenda and be evaluated according to its own standards; in particular, it “should not be seen as official development assistance ”. This is as much a matter of principles as of strategy: by not being considered ODA, cooperation provided by emerging donors remains out of the reach of their Northern counterparts’ regulatory agency, the OECDDAC. Part of the literature indeed points to growing concern by Western powers about losing their regulatory and even geopolitical grip over the international development apparatus . Emerging donors’ claims to difference and autonomy are at the root of much of the anxiety that, through their heterodox practices, emerging donors will “support ‘rogue states’, increase levels of indebtedness, ignore environmental protections, focus on extracting resources, and undermine the improvements that have been made over the past several decades” . The non-interference principle in particular has been considered as a threat to achievements in democratic governance and responsible budget management among aid recipients arguably brought about by the conditionalities enforced by Northern donors. These and other accusations are however as strategic as the move they are attacking: even when directed to non-DAC donors at large,plastic flower bucket its preferential targets are not Brazil or India but countries like Venezuela, Iran, and China. The latter in particular has been consistently accused of using this principle as an excuse for closing its eyes to corruption in its dealings with some African countries – the usual retort being that double standards are far from a privilege of Southern donors . The OECD-DAC is not the only agency in the international development community that has been striving to attract emerging donors to its bureaucratic and regulatory orbit: the World Bank has created its own apparatus to this end,and multilateral and bilateral donors have been increasingly engaging in South-North-South triangulation schemes.Emerging donors have shown mixed responses to these efforts, not only between themselves but within each of them; thus far, most have preferred to remain at arms’ length from the OECD-DAC, and to engage selectively with Northern actors and apparatuses . This ambivalence seems to be especially sharp in the case of Brazil, which has trodden a historical path that is somewhat unique amidst the major emerging donors. Differently from China and Russia and like India, it is a constitutional democracy and a former full-fledged European colony; but in contrast with the latter, Brazil has remained consistently within the geopolitical orbit of the West during its much longer history as an independent nation-state, including during the Cold War.

This belonging is manifested in quotidian language: while most Brazilians feel comfortable to talk about “Occidental” in the first person, in Africa and Asia “Westerner” is usually a reference to a third person. Like most other Latin American countries, Brazil participated only as an observer in the Bandung Conference, and was not a full member of the Non-Aligned Movement either – indeed, as the next chapter will illustrate, its stances on both neutralism and decolonization were at points ambiguous. In spite of some Brazilian politicians and diplomats’ whims about assuming leadership of the emerging Third World,36 no Brazilian ruler has ever attained the international status of notable leaders of the non-aligned movement such as India’s Nehru, Egypt’s Nasser, Ghana’s Nkrumah, Yugoslavia’s Tito, Indonesia’s Sukarno, or Tanzania’s Nyerere. Indeed, during my fieldwork in West Africa the only Latin American figure I saw referenced and stamped in vans, motorcycles and walls was Ernesto “Che” Guevara. And one would assume that Che gained such lasting popularity due not to his Argentinean nationality, but to his participation in revolutionary Cuba’s efforts to support liberation and anti-apartheid struggles in Sub-Saharan Africa. Not surprisingly, then, other than Bandung a common landmark in historical accounts of South-South cooperation from the point of view of Brazil has been the Buenos Aires Action Plan. It instituted a regulatory framework for Technical Cooperation Among Developing Countries , in a meeting sponsored by the United Nations in Argentina in 1978.One can fathom the reasons why this event would find special purchase in Brazil: it was held in Latin America, was a more recent event than Bandung, and was fully codified by the UN’s framework. Different from China and Arab states, for instance, Brazil has relied significantly on the UN apparatus: the Brazilian Cooperation Agency was itself created with the aid of the United Nations Development Program , and continues to entertain key operational relations with it as the country turns from receiver to provider of cooperation. Another global development frequently mentioned by Brazilians has been the rise of a group of countries which are regarded as emerging out of a condition of underdevelopment, codified in the acronym BRIC – coined by a Goldman Sachs executive in 2001 and eventually appropriated by these countries themselves.As the appropriation of the BRIC acronym shows, Brazil’s rise as an emerging donor has been as much an internal as an external formulation. On the one hand, there was a strong foreign policy drive: much of the recent spike in demand for Brazilian cooperation coming from Africa and elsewhere has been attributed to the enhanced visibility of Brazil’s newfound status as a donor promoted by what has been referred to, in the media and reports, as the “presidential diplomacy” of the Lula years . This notion refers to the special attention former President Lula dedicated while in office to the global South and to SubSaharan Africa in particular, manifested in a personal commitment with spreading the word about Brazil’s new status as an emerging donor.Others have disputed the centrality of his figure, claiming that demand for cooperation would have augmented anyway along with Brazil’s rise to global prominence, which is not only political but, perhaps most fundamentally, economic: “it wasn’t Lula who put Brazil in the BRIC group”, one of my interlocutors in Brasília insisted. Indeed, Brazil has long been given a prominent place in the shifting typologies found in global bureaucracies. From the point of view of Northern donors, Brazil lies at the “good” end of a broad spectrum of countries the impressions on which range from a welcome and “valuable complement to North-South cooperation” to a fear that they might end up “underwriting a world that is more corrupt, chaotic, and authoritarian” . In the case of Brazil’s rise as an emerging donor, we therefore find a dovetailing of a horizontal, Third-Worldist and a vertical, Occidentalist axis that, at different points in history , has been manifested as inconsistency, ambivalence or contradiction, but also flexibility and strategic leverage. Thus, even while remaining friendly to the West and its institutions, like many of its peers in the emerging South Brazil strongly rejects the donor label, and the characterization of its activities as aid. This stance secures the country’s autonomy for crafting, implementing and evaluating its cooperation policies according to its own standards – a claim raised by government and cooperation officials, including some of my interlocutors, in response to international pressures for transparency and accountability. This stance also allows for greater flexibility and pragmatism in the translation of cooperation principles into practice. Finally, to align with Northern models and accountability standards would imply adding a bureaucratic and expertise burden to Brazilian cooperation’s already strained institutional apparatus that the country does not seem ready to afford. This indicates how ambivalent, multi-dimensional and politicized may be the relations between emerging donors and the broader apparatus of international development.

A modeling approach that relies on analyzing the individual farm operation as the unit of interest, as proposed in the types of models described in Rosen and Sexton, and Zusman and Rausser, has two problems. The first is that it misses the influence of non-farm voters on district decisions, particularly in popular-vote and board-appointed selection systems. The second is that the data requirements for a sufficiently broad empirical analysis quickly overwhelm the available resources for most studies of this type. A farmer proceeds through several decision-making stages in deciding what to plant, production levels, investment and water use. The initial choice is the size of the operation. The decision as to how much land to put under cultivation and irrigation is dependent on many factors such as how it is acquired , available financial resources, which crops are appropriate, past resource usage, variation in land quality, and distance to markets. Once this choice is made, a farmer chooses to plant and irrigate on their most “flxed” asset, land,wholesale plant containers to the maximum extent possible and selects that appropriate crops, water use and irrigation technologies on that basis.

Next the farmer selects the crops to be grown on this land. This choice drives other factor choices, particularly for water. Most crops require a fairly narrow range or “effective” water application as determined by local evapotranspiration requirements and land quality factors such as permeability, drainage and nutrient levels . The amount of effective water, e, is a product of the amount applied, a, and the technical efficiency of the irrigation method, h. The farmer then adjusts either irrigation technology/source or amount of applied water to compensate for changes in the other factor. As a result, the farmer faces a two-stage problem-first choose either water applied or irrigation efficiency, then select the other given conditions that dictate effective water requirements . Thus, the farmer first chooses optimal input levels for a particular mode and efficiency of irrigation, hi’ and selects the irrigation method that provides the largest net profits to the farm.The decision on how much water to apply can be a long-term commitment. Historically, only a few opportunities have arisen to acquire surface water supplies with the initiation or expansion of water projects . These water “markets” only opened for short periods and only offered long-term contracts. Water diversion is capital intensive and can require commitments up to 40 years with payments relatively invariant with actual usage. While water market opportunities now are expanding and environmental regulations are constraining supplies, even in these cases farmers face long-term choices.

Because of this time frame, the amount of water to apply from water district sources appears to be the dominant variable in choosing how to meet effective water requirements, and efficiency is a residual of these choices; thus we can leave a choice variable, h, to the second stage. The amount of effective water as a result is based on an expectation about the amount of land under cultivation, the price of water and of irrigation technologies, and the price and availability other inputs. The water-use efficiency variable, h, can be interpreted in several ways, either as improved irrigation technologies or as greater reliance on water sources autonomous from district supplies, such as groundwater pumping. This decision of selecting the appropriate irrigation technology and/or water source has a long lead time as well and requires year-to-year planning to change. The expense of selecting a different technology is captured in the investment cost of the technology, I, and the cost of pressurizing the irrigation system or for local groundwater pumping, v. However since h = AlE, these costs are actually dependent only on the amount of water applied, a? Thus v and 1become functions of a as well. Perhaps the most important reason for forming any water district is the provision of a reliable water supply. The issues of overall supply and service quality must be addressed collectively because they have clear “common property” traits.

Adding capacity to a reservoir is likely to improve everyone’s supply reliability within the district if the water rights are effectively “correlative” . Defining the property rights to this added capacity would undermine the cooperative nature of the district. The district is then searching for the “optimal” choice for these variables based on a set of rules. These rules begin with deriving the opportunity cost or “shadow value” of the water supply. The choice of the supply capacity, S, directly influences reliability–the greater the storage capacity and transfer capability, the longer the district is able to carry over storage during drought periods. In other words, the probability that full water deliveries will be available, F, increases with the size of storage capacity, S. The average supply availability below full deliveries is the sum of the probabilities of these lesser flows . However to simplify this problem, we can present it as a dichotomous probability case of either full deliveries or drought constrained deliveries without any supply capacity, Sd, which equal approximately the average of the less-than-full delivery conditions. Often the terms “efficient,” “social-welfare maximizing” and “wealth maximizing” are often used interchangeably by economists as though they represent much the same measure. However, attaining the maximum wealth for a group may not be the most efficient outcome because two individuals still might want to trade among themselves. This results from their respective preferences changing at nonlinear rates. Perhaps even more confounding is that the distribution of wealth may also be important in attaining the preferred level of social welfare. Because the classical model often uses monetary measures of well-being, through profits, it reduces the definition of efficiency to maximizing wealth. The problem with defining efficiency solely in terms of net monetary benefits is that the “cooperative” has key difference from the “firm” in the neoclassical sense—cooperative members maximize over their individual preferences which may include non-monetary outcomes, while a firm’s shareholders only derive monetary returns. For comparative purposes though, we define our efficiency measure in this reduced simplistic form, which in turn may be somewhat misleading in a political-economic analysis. If an agricultural water district was managed as a wealth-maximizing cooperative,plastic pot manufacturers it would choose the mixture of investment in water-supply capacity and agricultural production that would generate the greatest net benefits for its members. Water would be priced at its marginal cost internally to signal the most efficient uses to members, and any net profits or losses from water- supply operations would be returned to district members in a fashion which would not distort water-use decisions. In fact, this model is institutionally quite different from the way public enterprise district operate. Existing districts have several characteristics distinct from this model. The most important is the so-called “non-profit” requirement, i.e., that expenditures and revenues must be in approximate balance. Revenues are often limited to sources directly linked to water-use, e.g., prices, charges or property taxes, and thus pricing must approximate average, not marginal, costs. The net benefits from the district also may be allocated in any number of ways, some of which distort water-use choices by farmers.

Finally, water district board members tend to choose policies which allow them to continue to hold office. This means pleasing enough constituents to gain a majority of votes. Policies that increase total district wealth may benefit only a few district members and not generate sufficient political support. Even though the “efficient cooperative” model may not be appropriate institutionally, it is useful as a benchmark to measure performance by other institutional forms. One can assess how a district’s manager might choose to maximize total wealth if the manager could control all internal resource management decisions either through directives or complete internal pricing mechanisms. Thus, this is more appropriately called the “wealth-maximizing” model. This model assumes that farmers see the full and direct costs for the water resources that they use and receive back the net profits from the operations of the district. The institutions that manage and price such water resources are “transparent” in this case. The district does not face a non-profit constraint, nor must it decide how to return any excess profits to district members. Distribution of total benefits is not addressed in this model. However the model provides a useful measure for comparing the different institutional arrangements that water districts use in California. In the efficient cooperative model, we assume that an “omniscient central planner” allocates all resources to produce the highest level of total district net wealth. Of course, in reality these functions are institutionally segregated between an elected or appointed governing board and the individual farmers. In the latter case, the issue becomes coordinating the actions between the farmers and board members through “signaling” such as pricing and voting. This is .confounded by the effects on these signals of distribution of that wealth among district members-the “political economy” of the district. District board members try to stay in office by pleasing a sufficient number of constituents through their policy choices. They attempt to win a majority of votes by addressing the issues that most affect district members. This is the basis of the median-voter model . This idea can be extended to incorporate the “interest group” concept by assessing how voters grouped by key characteristics might respond to different policy choices, and determining whether board members can assemble a majority vote by appealing to these various groups . The existence of different voting rules in California’s agricultural water districts allows us to test this hypothesis. Several different methods are specified in state law to identify qualified electors and how to weigh votes for electing governing boards. The two dominant methods are the property qualification, assessed value-weighted method and the universal-franchise, popular vote method.9 The former allows only those who own property to vote, and each owner is given a vote in proportion to the assessed value of their land. This method might be interpreted as allocating votes in proportion to the value of net output from an agricultural district. The latter method enfranchises any registered voter and simply tallies one person/one-vote. This is also the most common method for electing officials in other governmental jurisdictions. While a board cannot guarantee that a particular voter will vote for them, they can affect the likelihood that they will receive a positive vote. The board has five variables to consider: who the eligible voters are in the district, the well-being of the district’s individual voters, the cost of the district’s water supply, the variability and reliability of the district’s supply, and the mode of collecting the district’s required revenues. We focus on the district board’s objective function which is to maximize the number of voters subject to meeting a non-profit budget constraint. The function y specifies the relationship of individual net benefits for district voters and the likelihood of those voters voting for the incumbent board. y can be interpreted as a single utility function in which the output is a “yea” or “nay” vote on the current district management. For purposes here, we need not specify the exact function, but only note that y increases as net benefits increase for members within each interest group.The objective function for a tenant farmer differs from an owner/operator in two ways from that of an owner. First, tenant farmers are more likely to incorporate a risk premium, p, on fixed irrigation technology investment due to the nature of tenancy versus ownership . Tenants risk not being able to fully recover investment costs since they do not control land use and cannot regain fixed investment in the land value. In other words, their risk of sunk costs in investment stand to be substantially higher. This effectively increases the apparent cost of upgrading irrigation efficiency if we assume improvements require higher fixed investment . Second, a property tax has only a secondary effect through the rent on land costs to tenants. A portion of the property tax incidence is on landlords. Thus tenants do not fully realize the brunt or benefit from changes in this type of tax. Models for two different types of water districts are evaluated in the next two sections. Each model is constructed in parallel to the constrained efficient cooperative to allow direct comparison.

Similar results were found for tropical silvopastoral systems where the canopy cover and tree density were positively related with migratory bird flocks . In a comparison of different structural complexity, silvopastoral systems supported less diverse bird flocks than shade coffee in Colombia, but it is likely that shade coffee could support more bird species than open grazing lands . In Romania traditional silvopastoral systems of open oak woodland forest-pastures harbored more diverse and significantly different bird communities than modern high intensity managed open pastures .In Europe and North American prairie bird populations are declining due to agricultural intensification, resulting from the redusction of crop rotations, use of pesticides, and landscape simplification . In terms of habitat preferences, Skylarks were significantly positively influenced by legumes and set-aside, , a field with no or low agrochemical inputs, with weeds and wild flowers/grasses and low/ no tillage. In a meta-analysis, Van Buskirk and Willi found that set-aside in conventional agriculture increased bird richness and abundance ,container size for blueberries although set-aside parcels had greater benefit when surrounded by low intensity agriculture.

Floral diversity associated with diversified farms was shown to support a variety of grains and plant biomass for granivores bird species that use arable land as habitat , but depletion of these food resources via agriculture simplification and use of herbicides was found to negatively impact the granivorous populations . The interactions between bird habitat associations at the plot/local scale and landscape scale factors are relevant for implementing conservation strategies in arable lands, for instance, granivores species were prone local extinctions when arable land decreased in the landscape . Lowland rice fields are useful for bird conservation due to their similarity to natural wetlands . In Asia, the integration of wildlife with rice crops in wetland areas drives synergies between nutrient cycling and pest control. In the case of rice fields, ducks provide ecosystem services such as consumption of weed seeds, aquatic arthropods and rice pests, release of nutrients , and soil aeration, while rice fields provide ducks with shelter, nesting places, and food resources . In an exclusion experiment in rice flooded in winter in France, Brogi et al. reported that domesticated mallards mimicked wild populations of mallards by removing rice crop residues , independent of duck density, thereby accelerating the decomposition process post-harvest in the field. Long et al. compared duck-rice agroecological management and conventional rice farms and showed that duck-rice management effectively controlled insects , improved soil fertility and organic matter content, and reduced greenhouse gas emissions. In addition, Cagauan et al. recommended integration of water fern and fish in order to increase nutrient cycling within the duck-rice agroecosystem. The agroecological management of duck-rice farming is not only the reduced use of agrochemicals, but also improved yields and economic returns for low income farmers in Bangladesh .

To enhance conservation of waterbirds in rice fields, Elphick et al. suggested key agricultural management practices such as decreased use of pesticides and promoted field flooding. Harvest method , crop residue management , water management , agricultural management , and manipulation of edge fields and provision of landscape ponds and ditches are all practices that can benefit birds. Orchards provide vertical structures that can be used as habitat for birds. In central Chile Muñoz-Sáez et al. found that orchards as land cover at two spatial scales favored the abundance of five species including granivores, insectivores, and omnivores birds. Woody crops such as olive orchards can be beneficial for frugivorous birds, especially in winter . Castro-Caro et al. conducted a study relating bird richness with effects of ground cover in olive orchards within homogenous and heterogeneous landscapes. Their results showed that the effect of the herbaceous ground cover was beneficial for passerine birds , independent of the landscape category, suggesting that landscape structure did not play a significant role in determining bird species diversity in fruit orchards. Almond orchards were reported to host higher bird richness in Eastern Australia than in apple orchards, vineyards, and Eucalyptus woodlots, including the threatened Regent Parrot . Apple orchards can also be useful for birds species, in particular when managed organically, increasing the number of insectivores in comparison with conventional orchards or serve as habitat for woodpeckers . Orchards can be sources of tree-cavities that are relevant for secondary cavity nester birds .Agroforestry is proposed as a multifunctional system where agricultural and forestry productivity, ecosystem services and biodiversity conservation are simultaneously enhanced . In a meta-analysis Torralba et al. found that in agroforestry systems, biodiversity, soil fertility and soil erosion control is higher than in conventional agriculture and forestry.

Leakey highlights the functional role of trees in agroforestry: increasing soil fertility , increasing water infiltration and habitat for mycorrhizae, and providing habitat for wildlife, among others. Several studies have shown that multi-strata and diverse agroecosystems can provide habitat for many species, and increase conservation potential in these areas . In tropical ecosystems, cacao and coffee are usually grown in agroforestry systems, as these crops are naturally adapted to shade conditions. In a comparison, between shade and sun coffee, Johnson et al. found higher diversity and abundance of insectivorous and resident birds in shade coffee than in sun coffee. Van Bael et al. reported a similar magnitude of bird predation in agroforestry systems in comparison with adjacent forests, and reduced insect abundance and plant damage, particularly due to migratory birds . Nájera and Simonetti found that increasing complexity can enhance biodiversity in forest plantations, although different species have a diverse response to management . Colorado et al. found that highly structured coffee agroforests favors Neotropical migratory birds, including the provision of overwinter habitat. In Malaysia, oil palm forest supports less birds and has lower abundance of insectivores, omnivores and granivores but higher abundance of raptors and wetland birds in comparison with logged peat swamp forest . Although the bird communities supported by agroforestry remain high, the bird diversity is notably not the same as in the native forest. These agroecosystems were inhospitable for some of the forest specialist birds that rely primarily on food and resources present only in native ecosystems . Interestingly, it has been reported that bird richness could be higher in cacao agroforest plantations in comparison with native forest, although species that inhabited agroforest cacao were common generalist . However, bird diversity supported by agroforestry systems is higher than supported by agricultural monocultures .Although the adoption of agricultural techniques and practices dates back 10,000 years , agricultural landscapes were traditionally considered incompatible with conservation biology goals . More recently,raspberry grow in pots agricultural management and the adoption of different techniques and approaches have the potential to reduce negative impacts on bird populations and even enhance bird populations . The use of pesticides has been recognized as detrimental for non-target species since Rachel Carson published Silent Spring, documenting the impacts of DDT on bird breeding. After the banning of DDT in several countries, a new family of chemicals appeared with new impacts for wildlife. Neonicotinoid pesticides have heavily impacted bird populations via depleting insect populations, a bird food resource. It was shown that neonicotinoid pesticide could disrupt the thyroid gland in birds which affects the endocrine and reproduction systems . Neonicotinoids and other pesticides can persist in soil and soil water in the long term and their indirect effects are poorly understood . Reduced reproduction rate of secondary cavity nesters was reported in apple orchards sprayed with organochlorine pesticides . Granivores birds are also affected by the ingestion of pesticide treated seeds . It was reported that cumulative pesticides applications over multiple years decrease bird community specialization, favoring a few generalist species capable of persisting in simplified arable monoculture . In contrast, Henderson et al. , showed that use of poly cultures and reduced pesticide amounts increased grassland bird populations. In a risk assessment using birds as an indicator species to compare alternative farming systems with genetically modified herbicide tolerant crop production in the UK, wildlife friendly farm management provided better conservation outcomes via better provisioning of food resources and nesting habitats, in comparison with transgenic crops .

Misuse of pesticides have unintended consequences for non-target organisms and undermine environmental health for wildlife and humans. Organic agriculture is widely conceived of as a management approach that relies on optimization of natural cycles, avoids the use of synthetic fertilizers, pesticides and genetically modified crops, and minimizes external local impacts to the environment , although specific practices vary greatly between farms and certification schemes. Common practices include use of organic matter additions , crop rotations, greater reliance on biological nitrogen fixation by legumes, mechanical weed control, and the use of biological control for pest regulation. Organic management enhances biodiversity as reported by Rahmann in 82% of the 396 papers analyzed. Although the total surface area of certified organic agriculture corresponds to about 1% of the global agricultural land worldwide , organic agriculture has been reported as beneficial for wildlife in comparison to conventional agriculture . Tuck et al. in their meta-analysis documented a 34% increase in species richness of multiple taxa in comparison with conventional agriculture, a gain that remained stable for three decades. Plants benefited most, but positive effects on arthropods, birds and microbes were also reported . In a meta-analysis for Europe and North America Wilcox et al. found that for arable crops, bird abundance was higher in organic agricultural management than conventional management, although the response varied by species traits. Several studies on different taxa corroborate the positive effects of organic farming within the field and at its boundaries on plants , birds , insect pollinators , natural predators , soil microbial activity, beneficial arthropods, and earthworms . A smaller number of studies have reported a neutral influence of organic agriculture on biodiversity in comparison with intensive management, such as for birds within vineyards in Italy . Some authors contend that the benefit of organic farming varies with the taxa studied and the landscape context. For example, Gabriel et al. reported that landscape context interact significantly with organic management practices, such that conservation strategies should be considered from a ‘local perspective’. The effectiveness of organic practices to increase biodiversity likely depends not only on agricultural management, but also on structural diversity at different landscape scales . In terms of bird dietary groups, Genghini et al. found that in fruit orchards in Italy insectivorous birds were more abundant in organically managed fields than in conventionally managed fields. Similarly, Smith et al. reported that organic farms positively influenced insectivores birds only in monocultures surrounded by borders of semi-natural grassland. However, organic management had a positive effect on non-passerine birds richness independent of the vegetation context . Tillage is a common management practice worldwide to homogenize and standardize land cover surface, increase contact between the seed or crop root and soil, and for weed control and pest turnover.Tilled crop lands are not considered high quality habitat due to frequent soil disturbance and typically monoculture planting and high agrochemical application levels common in intensive agriculture . In terms of soil conservation, zero tillage or conservation tillage is a more environmentally friendly technique due to low impact on soil structure, reduced soil erosion, and increased soil carbon sequestration, with similar medium- and long-term yields in comparison to conventional tillage , however high levels of herbicide application on such systems remains a concern. Positive impacts of conservation tillage in comparison to conventional tillage has been reported for some farmland birds in the UK, particularly in late winter . Zero tillage can also increase seed and invertebrate availability which are key food sources for birds . In a comparison between no-till and conservation tillage in a soy monoculture, VanBeek et al. reported a higher abundance of birds with conservation value, higher nesting and higher nest success in notill in comparison with tilled farms. Shutler et al. reported higher abundance of birds in notill than in conventional farms in Canada, although all of the species were more prevalent in wetlands and wild sites than on farms. In Illinois a study compared the nesting success of birds under till and no-till soy crops and found a higher nesting density and nest success in no-till farms probably due to shelter and food resources provided by crop residues and weeds . However, it has been reported that no-till in corn–soy rotations can act as an ecological trap, due to birds’ perception of no-till cropland as suitable habitat and the subsequent negative impacts on nesting of farm equipment traffic and herbicide/pesticide applications common in such systems .

One possible measure is farmland value, which presumably reflects long run profitability, and which has been used quite extensively since Mendelsohn et al. introduced the so-called Ricardian approach for assessing the impact of climate change on agriculture. With this approach, one estimates a Ricardian or hedonic regression relating farmland value to climate variables and to other variables that control for non-climate factors which might also affect farmland value. This approach is intended to capture the long-run impact of climate on farmland value, and it allows for farm-level adaptations that might be undertaken as climate varies. In their paper, DG question whether there are unmeasured and omitted variables that also influence farmland value and that might be correlated with the climate variables in such a way as to bias their coefficient estimates in the hedonic regression. DG’s important methodological innovation is to propose an alternative approach using fixed-effects to control for time-invariant idiosyncratic features of the county within a panel data setting. However, for this approach to work, one cannot use climate variables as regressors since, in practice,blueberry production these are likely to be fixed over the duration of the panel and, hence, perfectly collinear with the county fixed-effects.

For this reason, DG use annual weather rather than long-run climate, since weather does vary over the course of the panel. Also, because of their annual focus, DG use annual “profit” as their metric of value rather than farmland value; this becomes the dependent variable in their regression. They are thus measuring the effect of weather on short-run profit rather than that of climate on long-run farming profitability or land value.They find no statistically significant relationship between U.S. agricultural profits, proxied by sales-minus-costs as reported in county-level data of the 1987, 1992, 1997, and 2002 agricultural censuses, and weather variables in the same years. They also find no statistically significant relationship between yields of the major field crops corn and soybeans and weather. They conclude that if short-run weather fluctuations have no influence on agricultural profits or output, then in the long-run, when adaptations are possible, climate change is likely to have no impact or will even prove beneficial. With any measurement strategy there are benefits and costs, and the ultimate effectiveness of the strategy is an empirical question.The benefit of DG’s strategy is that it is less vulnerable to unmeasured and omitted time-invariant factors.

DG argue that their measure overstates any possible long-run adverse impact of climate because it reflects the short-run response to fluctuations in weather and therefore does not allow for longer-run adaptation, which could only be less costly. But there are also many ways farmers cope with short-run shocks that would be more costly and/or less sustainable in the long run. For example, if the short-run response to a sudden increase in temperature is to pump more groundwater, this strategy may be less sustainable and/or more costly over the long run with a permanent increase in temperature than in the short run, due to depletion of the groundwater resource. In that case, the short-run impact of a fluctuation in weather would understate the long-run impact of a permanent shift in climate. Besides the conceptual issues associated with DG’s measurement strategy, there are serious questions about how they implement it and whether it actually produces the results they claim. Perhaps most importantly, there are some unusual features of the data used by DG and their representation of climate change scenarios that appear to influence their results, in each case in a direction away from finding any potential negative impact of the change. In our own research we have considered regression models that use both cross-sectional climate variations and time-series weather variations. In Schlenker et al. we show that a better-specified hedonic model that accounts for the influence of irrigation on farmland values is robust and predicts large negative impacts from projected climate changes.

In Schlenker and Roberts we find a strong relationship between corn, soybean, and cotton yields and weather, a relationship that indicates extremely warm temperatures sharply reduce yields for all three crops. Adaptation to warmer, or even extreme, temperatures, is suggested by DG and others, and this is of course possible, especially over time with the development of new crop varieties, but it is worth noting that we find no evidence of greater heat tolerance in yield regressions in warmer regions in the South as compared to cooler regions in the North, and no evidence that relative heat tolerance has grown over time. The relationship is strong and robust and very similar whether derived from time-series variations in weather or cross-sectional variations in climate and comparable in the cross-section of farmland values. Thus, while one cannot predict whether adaptations to extreme heat may occur in the future, there appears to have been little or no adaptation in the past . Climate models, in turn, project that the frequency of extremely warm temperatures will increase significantly. Holding fixed the locations where crops are grown, we predict potential losses in yields for key crops of approximately 30-40% by the end of the century under a slow- warming scenario and 60-80% under the fastest warming, “business as usual”, scenario. These predictions also accord with our research that uses the hedonic approach, where potential losses in farmland value range from approximately 30% to 70% for the same scenarios over the same time period. What explains the stark differences between our empirical findings and those of DG? With regard to DG’s results on profits and yields, we present evidence showing the difference stems from several sources: coding and data errors in the weather data that magnify within state temperature fluctuations by a factor of seven; an unusual and in our judgment incorrect characterization of climate change across the units of observation; differences in underlying climate change scenarios, in particular reliance by DG on an earlier and more optimistic climate projection than that used in the Fourth IPCC assessment and in our analysis; and DG’s omission of storage, and perhaps other financial or technological mechanisms, that smooth their measure of short-run profits in the presence of weather-induced output fluctuations and cause the short-run impact of weather on profit to understate the long-run impact of a permanent shift in climate.

To investigate differences we downloaded DG’s data and STATA code from the AER website. We found several irregularities in their weather and climate data. These data irregularities explain a large portion of the differences in findings. DG have two weather variables in their data set: the variable dd89, which measures growing degree days for each year and county, and dd89 7000, which measures the average number of degree days in each county between 1970 and 2000.3 These two variables do not appear consistent with each other. The correlation of the county-level average of the four-year panel and the 31-year average given in their data is only 0.39. Given the wide variation in temperatures in the cross-section,blueberry in container one would expect a stronger correlation between the 4-year and 31-year averages across counties. We reconstruct the same weather variables from raw data sources and find a correlation of 0.99. We also find the average of dd89 is much lower and the standard deviation much higher than in our replication. Second, DG’s baseline climate measure has a value of zero degree days for 163 counties. If correct, this measure implies temperatures do not exceed 8◦C in those counties during the growing season . Temperatures this low would seem implausible in any state, yet many of these counties are in warm southern states . Anomalies caused by missing or incorrect measurements, which as we shall show have an important influence on estimated impacts of climate change, are illustrated in Figures 1 and 2. We independently calculate the degree days variable dd89 7000 used by DG and display it in the bottom panel of Figure 1.4 Note the much smoother pattern as compared to the large discontinuous changes in the top panel. Average temperatures vary smoothly across space, where counties of the same latitude tend to have comparable average temperatures that increase as one moves southward. Exceptions to this rule are mountain chains like the Rockies in the West or the Appalachians in the East, where temperatures are cooler due to gains in altitude. The discontinuous pattern induces incorrect weather variation, which has an especially large influence on parameter estimates in regression models that use state-by year fixed effects. Within-state temperature deviations in our replicated data set are roughly one seventh of DG’s. Third, DG’s predicted changes under warming scenarios are discontinuous in space and range from a decrease of 880 growing degree days to a 6572 growing degree days increase . This pattern is odd given that the underlying climate model does not predict cooling anywhere in the U.S. and the variance of the projected changes far exceeds that of any climate model. Predicted changes in DG’s model and in our replication are shown in Figure 2. Again, compare the discontinuities in the top with the more coherent patterns in the bottom. The large variability of DG’s predicted climate changes stems from the way they combine observed weather and climate-change forecasts. The difficulty arises from the fact that general circulation models generate climate predictions on a coarser geographic scale than data available in historic records. DG use historic county-level data as a baseline combined with climate predictions that are uniform across each state. Thus, after climate change, Los Angeles and San Francisco, Salinas and San Joaquin Valleys, Mount Whitney and Death Valley, are all assumed to have the same climate since all are in California. Much of the within-state variation, however, is maintained in the baseline values, which are county-level averages. Such a representation of climate change therefore displays regression towards the mean, with cooler counties becoming much warmer and some very warm counties becoming cooler. This regression-toward-the-mean effect is accentuated by apparent errors in the baseline degree-day measure. Consider for example Fresno, Kings, and Tulare counties in the southern San Joaquin Valley of California. In DG’s data, Fresno is predicted to have a decrease of 414 degree days ; Kings county has an increase of 403 degree days and Tulare an increase of 4685 degree days . Tulare’s large increase is the result of a zero baseline. But even for Kings and Fresno counties, for which there are no missing baselines, predicted climate changes are too different for bordering counties. This treatment of climate change is unusual. We are not aware of any other application of the Hadley GCM model that predicts decreasing average temperatures by the end of the century in any U.S. location. Rather, the standard approach is to add regional predicted changes from the climate models to the sub-regional baseli While there are differences between DG’s and our own model of yields, much of the difference in our predicted impacts stems from the data issues described above. We generally find large negative projected climate impacts from replicated profit regressions as well, though results here are somewhat mixed and less likely to be significant, for reasons we discuss in the next section. Comparisons of the original and replicated yield and profit regressions are summarized in Tables 1 and 2. In our replications we fix the observations so they exactly match those used by DG. This excludes some agriculturally important counties, which are missing in DG. For example, 66 of Iowa’s 99 counties are missing from their data set, yet Iowa is the largest producer of corn and soybeans, in turn the nation’s two largest crops. On the other hand, most of Nevada’s counties are included, which are highly irrigated. Irrigation poses a problem for estimation of the effects of climate variables both in a cross-section and a panel. In a cross-section such as the Ricardian or hedonic approach the problem is that since irrigation tends to be correlated with temperature and precipitation it can bias estimates if omitted, as we discuss later in the section on robustness. In a panel, the effect of weather fluctuations depends on water availability. DG deal with this problem by estimating regressions with separate coefficients for irrigated and rainfed counties.

Even based on observed pK changes, CMA,pK=0.044. If weighted by the greater increases p*K, the MA demand augmenting impact of capital price changes would be C*MA,pK =0.056. The implied higher growth of virtual compared to measured price of capital could result from various factors. Its drivers could include substantive and rising adjustment costs , environmental or safety standards, or taxes, that are not effectively captured in the measured user cost of capital. These capital costs motivate a substitution effect toward primary agricultural products. In turn, growth in the scale of production, or output demand, has had a greater-than proportional effect on the augmentation of MA demand; eMA,Y=1.095 on average for the full sample, implying CMA,Y=0.024.24 And although eMA,Y>1 implies scale effects are MA-using, they are even more MF-using, so in this sense they are relatively MA-saving. By contrast to the positive substitution and scale influences on MA use, disembodied technological shift impacts on MA demand have been negative, and in a direct sense, quite large. That is, an input-cost-diminution impact associated with MA demand is evident = – 0.008 on average, that is typically interpreted as deriving from disembodied technical change.

This trend is statistically relevant; the eMA,t estimates are significantly different from zero for most individual observations.25 And this tendency was augmented post-1980 = – 0.021. The direct t- and t2- impacts are, however, much greater in magnitude than these total measures,big plastic pots since much of the direct trend effects are counteracted by effective price trends that may be interpreted as embodied technical change or adjustment costs, as alluded to above. These patterns can be seen from the decompositions of the total trend and structural change impacts in the first section of Table 2, that arise from the inclusion of t- terms in the p*MA and p*K specifications.For our scenario, although eMA,pMA < 0, since the trend component of p*MA is negative , the indirect p*MA effect on MA demand is positive – as is the p*K effect since K is a substitute but p*K is rising .This evidence is consistent with the embodied technical change interpretations of the timpacts on effective prices implied by the discussions of the p*MA and p*K as compared to pMA and pK changes above. Declines in effective as compared to measured pMA, and the reverse for pK, both tend to augment MA use. Escalation of the equipment-to-structure ratio, representing another form of embodied technical change, also had a positive impact on the demand for MA; CMA,ES = 0.014. Total Cost Implications In addition to the specific MA impacts, the total cost effects of adaptations in the economic and technological climate are of interest individually, as well as providing indications of input biases .

The cost effect most directly associated with the use of MA is represented by the eTC,pMA = 0.025 elasticity, indicating the impact on costs of pMA changes, which depends on the input intensity or average share of MA for industries that use agricultural commodities.This is larger than the corresponding elasticity for any other input; rising pMA has a substantive positive impact on production costs, and thus on output production/price, in the food processing industries. Note, however, that the overall pMA contribution to total cost increases of CTC,pMA=0.014 is not only smaller than that for capital , but is also is even lower if the smaller increase in effective pMA is recognized within this measure . The eTC,Y estimate of 0.868, which implies significantly increasing returns to scale, also deserves attention. This evidence is largely driven by a very small capital-output elasticity, that counteracts the eMA,Y elasticity of slightly more than 1, and an eMF,Y elasticity that is even higher , which suggests scale expansion is somewhat MA-using, and significantly K-saving and MF-using. This is of particular interest since this conclusion is closely linked to the inclusion of t in the lK and lMA specifications. When t is not included as an argument in these specifications , output increases instead appear MA-saving , and both eK,Y elasticity and eTC,Y elasticity estimates are much closer to 1, implying close to constant returns to scale. These patterns highlight two issues alluded to above. First, apparent declines in the MA-input-intensity of output production in the food industries are partly associated with increases in effective or quality-adjusted MA-inputs, perhaps due to embodied technical change. Second, adjustment costs for capital implied by a higher and more quickly rising p*K than pK may mean that these estimates should be interpreted as short-run, or at least capital-adjustment-constrained estimates.

And both of these impacts, if ignored, affect estimation of the scale- or output-effects. Finally, the elasticities associated with disembodied and capital-embodied technical change deriving from t and ES changes, and with structural changes in the 1980s , suggest other technological forces have contributed to cost diminution. The negative values for both CTC,t = -0.004 and CTC,t2 = -0.012, augmented by the embodied technical change impact CTC,ES = -0.041, highlight such trends, and their enhancement in the 1980s, and from technological advance embodied in equipment. However, the total disembodied technical change impact becomes positive – CTC,t = 0.0004 – when the higher cost of capital is recognized, even though the analogous effect for p*MA is in the opposite direction . By contrast, CTC,t2 is even more negative than its direct counterpart, since CTC,p*K,t2 = -0.0025 outweighs CTC,p*MA,t2 = 0.001. Note also that the input-specific CMA,t = -0.0525 measure is much larger than the associated overall input declines captured by CTC,t = -0.004, and the total MA effect CMA,t is negative whereas that for TC, CTC,t is positive, indicating that “technical change” has been both relatively and absolutely, MA-input-saving. Over time there has been a technical change bias toward reducing MA use more than other inputs for a given level of output.27 Marginal Cost and Output Price To move toward consideration of the pass-through of MA prices to output price, as well as its impact on scale economies, we can compare these estimates to those for marginal cost in the third panel of Table 1. Note that the input price effects for the materials and labor inputs are slightly larger for MC than for total cost,growing berries in containers implying a depressing impact on scale economies . The reverse is true, however, for the pK and pE elasticities, supporting the notion that capital is subject to adjustment costs, and “lumpiness”, that are driving forces for returns to scale. This is also consistent with the virtually nonexistent MC impacts of changing output. And with the fact that marginal cost has decreased significantly over time, both in terms of the direct and indirect effects, largely due to the smaller impact of pK on MC than on TC. Comparing these measures to those for pY provides some insights about markup behavior, and its determinants. The average epY,pMA = 0.272 elasticityis larger than either eTC,pMA, or the eMC,pMA. So a 1 percent increase in pMA drives a somewhat larger increase in AC than MC, and an even greater adaptation in pY than MC. This implies a higher markup pY/MC associated with a rise in pMA, but also an increase in the scale economies that support such markups .Note also that pY decreases somewhat more than MC as time progresses, primarily due to the larger p*MA effect. Temporal and Industrial Variations In addition to the indicators for the data averaged for the entire sample, it is useful to briefly consider variations in the estimates over time and by industry, which are presented in Tables 3 and 4, respectively.

The temporal decompositions presented in Table 329 show a much smaller depressing contribution of pMA increases to MA demand post-1980, that results from low pMA growth; the measured eMA,pMA elasticity is actually larger later in the sample. Also note that the trend in the effective price of MA is actually downward for the post-1980 period, so the full contribution of own price changes to MA demand is positive. This tendency is particularly worth highlighting since measured pMA changes that occurred after the end of our sample period actually dropped, which implies that the implications from these measures may have been exacerbated. It also appears that although the growth rate of MA demand in the 1980s was larger than in the 1970s, the individual input price contributions were generally smaller, with less of the growth arising from output increases. In fact, a large proportion of MA demand expansion seems to have arisen from t-effects. In particular, the indirect p*MA effect has increased over time to the point where CMA,t is positive post-1980, although the direct impact, CMA,t, reported in Table 2, remains negative in the later time period. The TC measures for the 1970s as contrasted to the 1980s, presented in Table 3, indicate a much smaller average annual percentage increase in total costs for the food processing industries overall post-1980, that is only in part due to a slower output growth rate . All the contributions of individual TC determinants are smaller , although they remain statistically significant. In particular, the eTC,pMA elasticity is slightly lower in the 1980s, but the contribution falls more since pMA increased so little . The -estimate of the actual TC change in the 1980s seems to be driven by capital price effects, which appear in the CTC,pK measure of 0.014, as well as a positive CTC,p*K,t measure of 0.009 which augments the direct CTC,t = 0.004 .30 Although a full analysis of the 3-digit industries within the food processing aggregate is beyond the scope of this study, it is worth briefly considering the differences in MA demand that are apparent across these sub-samples, as reported in Table 4. First note that for the meat products industries very little substitution is apparent, as might be expected.Note also that the t-effect is very small, at only about 10% the magnitude of that for these industries as a whole. For the dairy industry, the own and cross-substitution responses seem similar to those for the overall food processing industries. But the t impact in total is very slightly positive, since the indirect adjustment – particularly the CMA,p*MA,t component – is quite large. The vegetables sector of the industry seems to be fairly responsive to the own price of MA. The p*K contribution, as well as the t elasticities are also large. The substantial t impacts on p*MA and p*K in fact suggest a particularly significant amount of embodied technology in the primary agricultural vegetable inputs, as well as high and increasing adjustment costs, likely due to the great scale and processing expansion in this industry. The grain mill and oil industries have exhibited quite different patterns.31 We find a negative output impact on MA demand for grains, both due to the very low eMAY elasticity , and observed output declines for some observations. Responsiveness to other factors seems generally low in this industry, except perhaps for ES. For the oil industries, we find the own contribution to be smaller than for most industries, and even less responsiveness to prices of other inputs, and thus substitutability; the cross-demand contributions are only about half those for the food industries as a group. By contrast, the output response is the largest of any other industry on average. For sugar and confectionary products the own price contribution is by contrast very large, although other substitution effects are somewhat small relative to the other industries. The pK impact is slightly more minor, and the CMA,t impact more major, than for the industry as a whole. And industries in the miscellaneous category have exhibited similar substitutability patterns to those apparent for the overall industry, except for very small capital/energy and technological contributions. Impacts of MA Price Changes Finally, in Table 5 we report elasticities that facilitate an evaluation of responsiveness to pMA changes, which may be thought of as a converse experiment to the evaluation of MA demand changes that began our discussion of empirical results. These measures facilitate investigation of the potential implications of the declines in pMA that were experienced by the food industries during the remainder of the 1990s not represented by our data sample.

In the piece, Boyd describes a heterogeneous network of firms, governments, and advocates developing REDD institutions simultaneously. He uses the metaphor of DNA to describe how frameworks and approaches from any particular effort can be combined and recombined into other efforts without passing through the bureaucracy of the UN. One respondent noted that a good deal of finance under the banner REDD has already begun to address drivers, well before the concept has acquired substantive meaning in the UNFCCC. “It’s hard to know which is the cart and which is the horse sometimes,” observed the respondent.For party and advocacy interviewees alike, the drivers themes is closely associated with a gathering debate about the appropriate uses for REDD finance. Several respondents noted that agricultural supply chains might be better suited to REDD finance than traditional government targets and forest landholders. Among this group, there was a sense that not only had existing lending been ineffective, it had been, as a consequence, heavily delayed by challenges finding appropriate borrowers and grantees. On the flip-side,blueberries in pots some advocates who are currently beneficiaries of REDD finance schemes argued that drivers are a low priority distraction that could threaten a “successful” model for REDD.

Yet another position questioned the wisdom of finance targeted for monitoring and evaluation of REDD at the expense of direct support for private sector activities. This subject argued that drivers might be helpful in rechanneling finance out of government hands and into the private sector. One respondent remarked that the insertion of drivers indicates a balkiness about the role of offsets from compliance markets to fund REDD activities. Drivers, this subject argued, indicates a growing credence in the “fund model” of REDD.In my interviews, several respondents keyed in on the “all parties” language in Paragraph 68 as signal of a focus on policy targets beyond landholders themselves and instead along land use-intensive supply chains. Several respondents saw the opportunity and some the need for synergy between formal REDD activities and other complementary government and NGO initiatives. Potential linkages mentioned included the commodity round tables . Others expressed hope that the legal model to crack down on the international trade of illegal tropical timber could be adopted for agricultural products.However, several parties have expressed skepticism about the political and legal potential of such a measure. The European Commission, meanwhile, has called for further research on the matter. In sum, demand-side and supply chain approaches to REDD represent a very different set of guiding principles than REDD as usual. In a sense, such approaches constitute the fourth cell of the 2X2—the public sphere as the root of the problem, and private sector as the site of intervention.

Finally how drivers relate to reference levels was a less common, but highly charged theme. Reference levels are estimates of the rate of deforestation in the absence of REDD. They are important to parties because they will form part of the basis for determining performance payments.61 In turn, drivers are important to reference levels because drivers are factors associated deforestation. One subject speculated that the high stakes of reference levels could pull along work to define drivers, but only if drivers are included in the reference levels discussion.Another, disagreed, worrying that linking the charged atmosphere of the reference levels debates with the efforts to define drivers could derail progress on defining drivers. The concern was that reference levels might politicize drivers and thereby limit progress to define them rigorously.Previous studies suggest that accelerating adoption of higher output, semi-intensive Brazilian cattle pasture intensification technologies can reduce direct GHG emissions, slow deforestation rates, and secure GHG benefits from bio-fuels production . Adoption of one or more semi-intensification technologies can directly reduce emissions from cattle systems by limiting enteric methane produced per unit meat and by reducing nitrous oxide emissions .

Direct reductions are notable, but they are an order of magnitude smaller than reductions estimated from avoided deforestation due to adoption of semi intensification systems. Such reductions could deliver a substantial fraction of the GHG mitigation pledged in the PNMC, Brazil’s Climate Law . Previous research suggests that land sparing from pasture intensification could also readily sop up the additional demand for land associated with bio-fuels mandates . However, previous estimates of the land sparing potential of cattle pasture intensification have shortcomings in their depictions of production systems, land use change processes, policies, and GHG impacts. One problem is the non-mechanistic representation of agricultural intensification processes. Rather than delineate all changes to the material and financial flows through the cattle systems, some studies depict boosted output alone. This approach does not allow representation of the full scope of mechanisms by which intensification shifts land use and therefore may misrepresent outcomes resultant from intensification processes. In such studies, intensification balances the spatial budget instead of depicting the land use change process using mechanisms consonant with economic principles and used at the cutting edge of land change science . Second, policies are also often highly stylized, depicted through constraints without practical analogs . Some modeled policies are implemented globally, belying limits to the authority of international law . Third,square plant pots though greenhouse gas emissions are of global salience and land use change processes are increasingly mediated by global markets, previous studies have focused on land use and greenhouse impacts at scales ranging from local to national . Global impacts from national land sparing policies have not been an explicit focus.This study investigates the global land use and GHG impacts of pasture intensification policies for achieving compliance with cattle ranching intensification targets specified in the Brazil National Climate Plan. We focus explicitly on three aspects of the problem that previous studies have not adequately addressed—a bottom-up, mechanistic representation of cattle production systems, policy interventions with practical analogs, and the effects of global trade. We employ the global economic land use simulation model GLOBIOM adapted to Brazil in order to represent global land use and GHG impacts of changes to land policies and pasture technologies in Brazil. The model consists of spatially explicit estimates of global crops, range lands and timber production potential spatially explicit product specific internal transportation costs in Brazil an economic model which represents the competition for land between the forestry, agriculture, and livestock sectors, and international trade for crops and livestock products. We introduce a semi-intensive pasture based cattle ranching alternative production type into the model. The production offers boosted yield per hectare and boosted costs of production per hectare. The main model outputs are crops, livestock and timber production, land use change, and GHG emissions from land use and agricultural sector, at a 50x50km resolution in Brazil for each 10 year-period over 2000-2030. Minimum levels of global food, timber and bio-energy demand are exogenously specified based on assumptions about population and economic growth.

We model two intensification policy mechanisms—a flat subsidy for all ranches adopting intensive alternatives and a flatly levied tax on all ranches that do not adopt intensive alternatives. Both of these interventions reduce the cost gap between higher cost semi-intensive alternative pasture systems and lower cost, business as usual pasture systems. We explore the extent to which international trade modulates the effects of these policies by comparing the model outcomes of freezing Brazilian external trade to the level observed in the baseline simulation or allowing external trade to adjust to the introduction of pasture intensification policies. The GHG impacts of the intensification policies are accounted as the difference between all GHG emissions over the modeled baseline scenario and all GHG emissions in each of the policy scenarios. In recent decades, the cattle sector of Brazil has expanded, shifted North and West, intensified, and become more export-oriented . Brazil has the largest commercial cattle herd, the second largest share of international trade in cattle products, and widespread adoption of semi-intensive pasture technologies. Semi-intensive adoption is largely associated with good domestic market access and fertile soils—higher rates of output per area can be found in the South, Southeast, and parts of the Center West of the country.64 Meanwhile, the geographic center of cattle production has continually migrated North and West in Brazil as an integral part of the frontier settlement and deforestation process . Internal demand for Brazilian cattle products is strong and growing. Per capita beef consumption is high and per capita consumption relative to GDP is higher. This despite the fact that prices are high relative to other countries of similar socio-economic status .Confinement facilities have emerged in the past decade, but they are cost competitive with pasture during only the height of the dry season and only in the core agricultural regions where land prices are higher than is typical . Age at slaughter has declined somewhat in the past two decades, but it still lags well behind producers in the U.S. and Europe . Growth in the sector has been uneven—fluctuations in currency, purchasing power, and export market access temper and enhance typical price dependent managerial fluctuations in slaughter rate and age class ratios known as the cattle cycle . Our baseline simulation depicts the period 2000-2030 in a fashion broadly concordant with the aforementioned patterns. Beef production in Brazil is simulated to increase to 13.4 million tons of carcass weight equivalent by 2030. This increase constitutes a modest 50 percent rise over production in 2011. Most of this increase will be associated with exports. We simulate Brazilian beef exports will to grow to represent 40 percent of the production in 2030 compared to 8 percent in 2000 and 24 percent in 2007 as reported by the United Nations Food and Agriculture Organization . The number of head of cattle is simulated to increase in all five political regions of Brazil across the simulation, but differentially. The Center West is simulated to remain the top cattle-producing region but its share would decrease due to rapidly rising cattle production in the North region . Part of the shift comports is due to agricultural expansion in the Center West and Southeast regions. Simulated crop farmers are willing to pay more for land than ranchers in these high fertility, market proximate regions. Prior to 2004, growth and change in the Brazilian cattle sector closely paralleled conversion of savannah and tropical forest in the North and West of Brazil . Remote sensing studies report that cattle ranching occupies between 50 percent and 80 percent of cleared Amazon rainforest land at some point in the initial years following clearing & Brazilian Agricultural Research Corporation , 2011. However, in key frontier regions, the last five years has seen growth in cattle production unmatched by concomitant land conversion . This discontinuity has been interpreted as promising evidence of land sparing, but it also highlights the challenges of estimating the extent to which marginal growth in the cattle sector contributes to deforestation. We revisit this theme in our discussion session. Nevertheless, in some periods, cattle pasture and crops expand in a concerted fashion. New croplands arise closer to key infrastructure while new pasture arises close to the agricultural frontier . However, it is often the case that croplands arise through conversion of pasture. The net effect seems to be that crops are expanding more rapidly than pasture. Past trends in the balance of pasture, croplands and native vegetation in Brazil continue in our baseline simulation. Pasture and crops undergo modest gains and, for the most part, these come at the expense of native vegetation. We simulate less land abandonment than the rate that has been empirically observed in the Amazon biome & Brazilian Agricultural Research Corporation , 2011. Land use change GHG effects from beef are uncertain, however, relative to other forms of food, beef is associated with substantially higher direct environmental impacts than other food products. Methane emissions, nitrous oxide emissions from soils, and nitrate water pollution are all major problems from cattle systems . Methane emissions aside, the bulk of the GHG effects are associated with land use changes that the literature attributes to cattle productions systems . However, these studies employ techniques for attributing land use change to cattle ranching that use correlational relationships between cattle pasture and deforestation as proxies for causal patterns.

In contrast to the notion that seepage water from wetlands may be considered as a source of groundwater nitrate contamination, this study shows that under the conditions present in our wetland, seepage through wetland soils can actually prevent some nitrate contamination of groundwater. Before recommending constructed wetlands that utilize seepage as a beneficial-management practice for treating agricultural tail waters, further study is necessary to determine the fate and transport of other contaminants . Studies are also needed to evaluate long-term nitrate removal efficiency over the life of these wetlands. While sealing the constructed wetland floor is considered an important aspect of treatment-wetland design, as it prevents the seepage of contaminants into groundwater bodies , it is not economically practical in most agricultural settings. Moreover, sealing wetlands can discourage surface water exchange with soils, which is where denitrification is most favorable.Initially developed by medical researchers to synthesize data from multiple clinical trials, large pots plastic systematic literature review and meta-analysis are increasingly popular in the agricultural sciences.

Systematic literature reviews apply a structured methodology to collect and analyse secondary data, with the objective of transparently reviewing all available research evidence . Systematic reviews contrast with traditional literature reviews, the former being thought of as more objective, defensible and conclusive . Meta-analysis takes systemic literature review further, fundamentally changing how research syntheses are conducted . It extracts and assembles quantitative information from primary studies to build a database for analysis. This enables increased statistical power and the testing of hypotheses that can only be partially addressed through individual studies. Rosenthal and Schisterman suggest that meta-analysis permits researchers ‘…to formally and systematically pool together all relevant research in order to clarify findings and form conclusions based on all currently available information’ . Most researchers conducting meta analysis collect means and standard deviations of response variables to determine treatment effect size . Meta-analysis of combined data from papers that individually report non-significant or idiosyncratic relationships between variables can point to an underlying data structure across studies. Both Garg et al.and Borenstein et al., therefore argued that increased statistical power is a key reason for deploying meta-analysis to address conflicting research findings and resolve scientific debates. Doré et al.recommended that agronomists conduct meta-analysis to investigate patterns in cropping system performance.

Over 1000 studies using meta analysis in agriculture have been published since 1985, with 65% completed since 2012 . Described as one of the most objective and robust methods in agricultural research , the usefulness of meta-analysis has however long been questioned in other fields. For example, Eysenck described meta analyses of clinical psychotherapy interventions as ‘an exercise in mega-silliness’ and an ‘abandonment of scholarship’ because researchers commonly included studies ‘mostly of poor design’ .In a more recent evaluation of 9135 papers labelled as systematic review or meta-analysis in health care, Ioannidis found one in six studies to be misleading, and one in three redundant, unnecessary, or potentially biased.Additional methodological concerns with meta-analysis have been identified in other fields that may be applied to the agricultural sciences. The first concern involves the criteria used to select and analyse literature. Failure to locate all available literature, or inclusion of primary studies with diverging or poorly implemented methods can lead to contradictory or erroneous conclusions . The greater availability of publications in developed compared to developing countries, and reduced accessibility of non-English literature may also compromise the comprehensiveness of research results. Publication bias, a condition resulting from journals’ preference to publish studies with significant rather than non-significant results, is one of several related issues .

Analytical techniques are now available to overcome publication bias, though they are inconsistently applied . Reviews of meta-analysis in agriculture include Philibert et al.and Brandt et al.who suggest that the methodological quality and application of meta-analytical techniques has been highly variable. Most meta-analyses in agronomy focus on crop yield response to experimental manipulation . Yield is however only one criterion by which the performance of cropping systems can be judged: yield stability and resilience, nutritional yield and environmental and economic performance are additional relevant but less studied indicators. Aside from the constructive critiiques of Philibert et al.and Brandt et al. , critical appraisal of meta-analysis in the agricultural sciences is largely lacking. This paper addresses this research gap considering a suite of yet-unaddressed issues of importance, starting with the ways in which meta-analytical research is framed. Framing can be defined as the way in which research questions and methods are selected, described and justified as contributing to solutions for particular problems , for example, agricultural productivity or environmental goals. When applied to rural development, Andersson and Sumberg refer to studies that reiterate these goals as belonging to ‘development-oriented agronomy’. Given heightened competition among agricultural scientists for decreasing research funds, research topics and investments are commonly justified using the language of development-oriented agronomy .

Meta-analysis may be also described as a descendent of the logical-positivist tradition of science that champions empirical and hypothesis-driven inquiry as the prime mechanism by which unbiased knowledge is generated and validated. Sumberg et al.and de Roo et al.conversely recognized the sociopolitically embedded nature of agricultural science. By doing so, they recognize the ways in which agricultural researchers in development-oriented agronomy experience tension between the generation of scientific evidence and the need to convince multiple audiences of the relevance of their research findings and types of agronomic practices. In addition to the narrative employed when agronomists design, interpret and discuss research results, we explore the ways in which this tension can influence the range of potential solutions to agricultural problems that may be proposed by agronomists conducting meta-analysis . Confirming the placement of meta-analysis within the logical positivist tradition, square planter pots researchers publishing meta-analyses in agronomy frequently highlight the size and representativeness of their datasets – which are usually constructed using observations from small-plot agronomic experiments – to answer agricultural development questions of continental or even global significance . Goulding et al.however cautioned that results from small-plot trials should be interpreted cautiously, as they may not include higher level processes and contextual interactions, and thus poorly approximate whole field- and farm-scale performance. Addressing these topics, we examine how meta-analysis has been used to support claims and counter claims over organic agriculture and conservation agriculture . In doing so, we critically assess the suggestion that meta-analysis can provide unifying conclusions and rectify topics of scientific debate . We adopt a ‘political agronomy’ perspective that recognizes the socio-politically embedded nature of agricultural science and suggests that agronomy can be an arena for contestation and debate . OA and CA are among the most widely disputed subjects in contemporary agronomy, with vigorous debate indicating large rifts in epistemological approaches and contrasting agricultural research and development paradigms . Considering these issues, we review prominent OA and CA meta-analyses published since 2007 and discuss whether meta-analysis has reduced or resolved research debate. We conclude by offering suggestions for how both scientists conducting meta-analyses, as well as the readers of scientific literature can more carefully evaluate meta-analytical evidence, particularly when applied in the context of development-oriented agronomy OA is defined by the International Federation of Organic Agricultural Movements as a production system that sustains the health of ecosystems and people, and that makes use of ecological processes and cycles to eliminate synthetic inputs .

OA is frequently equated with ‘ecological’, ‘agroecological’, ‘sustainable’ and/or ‘low-external input ’ agriculture, though each may differ in practice . OA is also generally contrasted with ‘conventional agriculture’, although the characteristics of conventional agriculture tend to be counter factually defined as anything not organic . Conversely, OA is commonly framed as a holistic and sustainable alternative production system, as well as a philosophy . Although debate over OA has a long history and has been recognized as being rooted in schisms between different agricultural paradigms , a systematic review by Badgley et al.concluding that OA could produce more food than required to feed the global population sparked much contemporary debate and paved the way for use of meta-analysis in OA-conventional systems comparisons. Subsequent and consecutive meta-analyses examining OA each claimed increasingly large datasets and comprehensive and conclusive analyses . This case study analyses key meta-analyses published following Badgley et al.and considers if meta-analysis has resolved or contributed to further debate over the merits of OA. CA involves three crop management principles. These include minimal soil disturbance, crop residue retention as mulch and crop rotation or diversification. Practiced in combination, these principles are meant to reduce soil degradation while increasing yields and reducing production costs . Although reduced tillage dates to the 1930s, widespread adoption began only after 1970, following the release of herbicides, mechanized NT planters and, in the 1990s, the advent of herbicide resistant, genetically modified crops . Erosion mitigation and reduced costs from the elimination of tillage appear to have been major drivers of adoption on large-scale farms in developed countries. These goals were however also considered imperative for smallholders in developing nations , sparking interest amongst international research and development organizations in CA . CA has since been widely reframed as a yield-enhancing technology to improve smallholder food security, with widespread promotion to smallholder farmers ensuing in sub-Saharan Africa and South Asia, in particular . This prompted critical debate over the suitability of CA in the context of development-oriented agronomy, and particularly the yield and adoption claims made for CA . This case study consequently considers eleven prominent meta-analyses on CA published since 2010, again asking if meta-analysis has resolved or inadvertently contributed to further debate.Contemporary debate over the productivity of OA emerged with Badgley et al. , who framed their paper as a response to objections that OA could make significant contributions to the global food supply. Badgley et al. compiled what they referred to as a ‘global dataset’ of 239 yield response ratios for a diversity of crop, meat, and dairy products . An average YRR of 1.32 was reported, indicating higher organic than conventional yields, with ratios in developing and developed countries averaging 1.80 and 0.92, respectively. Average ratios were extrapolated to estimate if OA could produce sufficient calories to meet global requirements. The authors concluded that OA could supply 17–50% more calories person–1 than the globally extrapolated average adult requirement per day. Badgley et al.also summarized 77 studies quantifying biological nitrogen fixation to estimate if legumes could supply sufficient of nitrogen annually to substitute for global use of synthetic fertilizer N. They concluded that OA could supply global food requirements without requiring additional land or fertilizer resources, and advocated strongly for increased institutional and public support for OA. The editors of Renewable Agriculture and Food Systems, which published the study, also permitted Badgley et al. to publicly reply to Editor and peer-reviewers’ concerns with their manuscript in a special Forum. Agronomists presented a range of technical critiques used to problematize Badgley et al.’s results and argue against increased OA research funding and support. Cassman , for example, critiqued the analysis of YRRs from singly grown crops, as opposed to rotational systems commonly employed in OA. Use of grey literature and concern over yield data collected in different years, e.g. before and after farmers adopted organic practices, were flagged as methodologically invalid. Such before–after measurements comprised half of the data from developing countries presented by Badgley et al. , and originated from a single report . Badgley and Perfecto however countered that organic-conventional comparisons were rare in developing countries, necessitating the use of before–after comparisons and grey literature. Importantly, Badgley et al.’s framing of OA was broad, including agroecological, sustainable or ecological practices that either exclude or make limited use of synthetic pesticides, and that improve soil quality. This definition differs from IFOAM and other certifying agencies, and was critiqued by Cassman as vague. The food policy analyst Dennis Avery argued that nearly half the studies in the Badgley et al. database used synthetic fertilizer or pest control products , which would disqualify them as organic under most certification programmes. Badgley et al.countered that practices using synthetic inputs in ways intended to reduce their application should still qualify as OA.

The devaluing pressure on the exchange rate would create an interest differential in favor of the foreign countries and a capital outflow which would increase the depreciating pressure on the exchange rate. Money supply growth would thus decrease proportionally and so would price inflation, at least initially. Real depreciation would then lead to an increase in demand . The increasing output demand would raise inflation, and thus real money balances would start to fall. Nominal interest rates would then increase, thereby restoring the capital account. Ultimately, real depreciation of the exchange rate and falling real money balances would bring the system back to equilibrium. With government intervention in agriculture, the government is able to “neutralize” any effect of foreign disturbances on domestic prices and demand. That is, the government can fix the target price at the existing domestic price level, allowing domestic producers to sell on the domestic market at the world price, with the latter below the former, and paying the difference. This kind of intervention amounts to a complete “sterilization” of foreign disturbances on the trade balance,plastic gutter the exchange rate, and on monetary growth and domestic inflation.

In the long run, this strategy would lead to unsustainable cumulative budget deficits; if the foreign price decrease is penn anent, an increase in domestic taxes is then necessary in order to finance the deficit. This, however, would lead to a decrease in disposable income with the consequent deflationary effects. Therefore, we define an intervention mechanism that allows zero-sum deficits in the long run. We will assume all non-farm government expenses are exactly balanced by tax revenues so that all government spending in agriculture amounts to a deficit in its budget. The resulting budget deficit must be either monetized or debt financed. Both operations have obvious effects on the money market, the capital account, and the trade balance. Increases in government expenditures which are debt-financed directly increase domestic absorption and income but do not have any effect on the monetary base. Increases in government expenditure financed by money creation directly increase domestic absorption and income and obviously affect money supply. In the fonner case, the overall long-run effect depends on the degree of capital mobility and be either contractionary or expansionary. In the latter case there are no real long-run effects. Without ruling out any of the two possibilities, the budget deficit is specified to be debt financed and partly monetized. The introduction of government expenditure in agriculture has several implications. First, the real effects of changes in money and in the exchange rate appear to be dampened. This accounts for the sluggishness of movements in prices, output, and the trade balance that occur because of “institutional” factors.

In particular, by acting on the way agricultural output reacts to changes in the monetary variables, the standard model is modified and all price deflationary or inflationary effects are lessened. Under this new framework, money is still neutral in the long run; but it has non-neutral effects in the short run which are smaller than in the standard model, and the overshooting in the exchange rate is smaller as well. Second, the entire dynamics of fann prices is altered. In the standard model, the differences in the dynamics of the two prices are ultimately due to their different degrees of stickiness and to the overall GNP share of the two sectors. These differences can, for instance, put the fann sector in a “cost-price” squeeze if manufacturing prices increase more than fann prices in the short run. With government intervention, farm prices are more protected; and if the degree of intervention is high, the overall real effect on farm prices of monetary contractions or of exchange rate appreciations can be nil, and thus the differential speed effect can turn in favor of fann prices. Third, several feedback effects other than the ones already present in the standard model can occur in the new fonnulation. Since the main scope of government intervention is to counter unfavorable movements in relative prices and to dampen the negative effects of monetary shocks on the fann sector, the impact on the money market and on the entire economy resulting from the financing of the budget deficit now represents one more channel of feedback from prices to money and the exchange rate. In order to introduce explicitly government intervention in agriculture, we assume that agricultural producers have a notional supply function of the type defined by Barro and Grossman .

This supply function depends mainly on two types of forces: a combination of policy indicator variables and excess demand pressures. The policy indicator variables represented here are target price, q, and a land reduction premium , v. Regardless of the market prices, agents who participate in government programs are assured a certain price of q. The second policy indicator serves to lessen the financial burden of accumulating stocks resulting from target prices well above market prices, e.g., under current legislation, an acreage reduction program is employed to assist in reducing producers’ supply.! The coefficients and c:o measure the weight that producers attach to the two arguments in the supply function. If ro is close to one, agricultural output is essentially demand determined. Alternatively, if c:o is close to zero, supply would be essentially determined by policy variables and relative prices. In a competitive world , if foreign prices fall below a certain level, then domestic producers will be paid the price given by q fixed at that level . The difference between the target price, q, and the world price, e + P:, is paid to domestic producers by the government. Target prices set above market prices create excess supply and large government expenditures to finance the implied level of subsidy. In order to reduce wide excess supply accumulations from target price incentives, the government affects producers’ decisions through the acreage reduction program. The higher stock accumulation,blueberry container the stronger will be the action of the government to reduce output supply. Although inventories are exogenous in our framework, it is clear that it is the interaction between the inventories and production costs on one side and between the inventories and interest rates on the other that plays a major role in determining the amount of acreage reduction intervention in agriculture. Given no trade barriers, an exogenous reduction in the foreign price of agricultural products would result in a shift of internal demand from domestic to foreign goods; a trade balance; and, thus, depreciating pressure in the exchange rate. With no intervention policy in agriculture, the monetary authority would then intervene by contracting the supply of domestic money on the world market. The pressure on the exchange rate would create an interest differential in favor of the foreign countries and a capital outflow which would increase the pressure on the exchange rate. Money supply growth would thus decrease proportionately, as would price inflation . Real depreciation would lead to an increase in demand . The increasing output demand would raise inflation, and thus real money balances would start to fall. Nominal interest rate would then increase, thus restoring the capital account. Ultimately, real depreciation of the exchange rate and falling real money balances would bring the system back to equilibrium. With government intervention in agriculture, we can have a quite different scenario. Suppose that, in the extreme case, the government wants to neutralize any effect of foreign disturbances on domestic prices and demand. That is, suppose the government fixes the target price, q, at the existing level, PA, and allows domestic producers to sell on the domestic market at the world price, e+ P:, where e+ P: < PA and pays them the difference .

This kind of intervention amounts to a complete “sterilization” of foreign disturbances on the trade balance, the exchange rate, and on monetary growth and domestic inflation. However, this could not last forever since, in the long run, this would lead to unsustainable cumulative budget deficits. If the foreign price decrease is permanent, an increase in domestic taxes would then be necessary in order to finance the deficit, but would lead to a decrease in disposable income with the consequent deflationary effects. Therefore, we need to define an intervention mechanism that would allow zero-sum deficits in the long run. These equalities highlight the relationships among the farm policy instruments. The two types of intervention can be interpreted as follows: The rate of increase in government financed price-target programs is guided by a rule that relates to the excess of the domestic price increase over the increase of the exchange rate. The higher the “support” coefficient, the higher the response in the rate of growth of government expenditure in price target programs. Hence, in the limit, as gl tends to infinity, the rate of increase in domestic agricultural prices is kept equal to the rate of depreciation. In the above case, the rate of increase of relative prices would be basically zero. What such an intervention rule shows is that the higher government support is, the lower will be the gains in competitiveness due to movement in the exchange rate and/or in foreign prices. However, although temporary shifts in competitiveness are minimized, the negative effects of the increase in the government expenditure for agriculture will have impacts on the government budget deficit and, ultimately, on the money market. On the other hand, the rate of increase in government-financed supply-reduction programs is guided by a rule that relates it to the excess of money supply growth over farm price inflation. The higher the intervention coefficient, g2′ the higher the response of government expenditure in supply-reduction programs. In the limit, all excess supply is “absorbed” by government intervention so that, ultimately, any excess supply is eliminated and the price growth rate is kept equal to the money supply growth rate. This amounts to assuming, in the limit, that agriculture supply is kept at the market-clearing level. It is clear, however, that even in this case all the budget effects of the supply-reduction programs will have an impact on the money market, depending on the magnitude of the intervention coefficients. It affects only investment and savings if the increased spending is financed by the sale of government bonds. The sale of bonds does not affect the domestic money supply since the funds obtained by the government from the bond sale returns to the public as the government spends it. Thus, the LM curve is not directly affected by the changes in government debt financed spending. Of course, if the increase in government expenditure is financed by the issuance of money, then both aggregate demand and demand for money will be affected. Increases in government expenditure which are debt financed directly increase domestic absorption and income but do not have effects on the monetary base. However, the increase in income heightens the demand for money, driving interest rates up. At the same time, all else constant, the increase has a negative impact on the trade balance, raising the demand for imports. The rise in the interest rates attracts capitals from abroad, restoring the capital account and counterbalancing the current account. Whether the balance of payments will be in surplus or in deficit will depend ultimately on the degree of capital mobility, the magnitude of the income multiplier, the willingness to save, and the propensity to import. If capital mobility is low, an increase in government expenditure has a negative effect on the balance of payments. Money supply decreases over time, due to the decumulation of international reserves, inducing income to decrease and partially offsetting the initial expansionary effect. If capital mobility is high, a balance of payment surplus will arise and money supply will increase, generating an additional income expansion over time. Increases in government expenditure financed by money creation directly increase domestic absorption and income and also affect money supply. The income effect generates a trade balance deficit through the increased demand for imports. The excess supply of money will be spent on foreign goods and also on foreign assets, thereby generating a capital account deficit. Complete adjustment will occur over time by means of net purchases of foreign goods. This slow adjustment will be reflected by trade deficits. In essence, the increase in the money supply through the printing of money will induce both the balance of trade and the balance of payments to worsen over the short run.

Barrier disruptions were attributed to the toxic effects of PFOS on f-actin, microtubule, and gap junction organization. Specifically, dose dependent PFOS exposure disassembled tight and gap junctions responsible for barrier function of blood-testis barrier, increased blood-testis barrier permeability, and disrupted spermatogenesis. PFAS chemicals have also demonstrated tight junction opening in brain endothelial cells, a main component of the blood-brain barrier, and increases in reactive oxygen species that increases endothelial permeability. PFOS was found to induce the remodeling of actin filaments through ROS production in human endothelial cells and increased gaps/breaks between endothelial cells in monolayers which resulted in increased permeability. Authors observed formation of central cell actin stress fibers and the formation of lamellipodia and filopodia structures at cell periphery. In alignment with the previous findings summarized, we observed the shift in f-actin expression toward the center of N/TERT-1 cells which could indicate formation of central stress fibers. The representative images shown display increased fiber formation near the center of the cells . We also observed the formation of filopodia structures at cell edges which were observed due to ROS production by PFOS by Qian et al.

Although we did not measure ROS production,greenhouse snap clamps is likely that these cell models are being affected in the same way; PFOS may increase ROS production by the host cell and in turn dysregulate the cytoskeleton. Importantly, previous literature showed that the disruptions caused to the cytoskeleton by PFAS increase permeability of crucial barriers such as the blood-brain barrier and the blood-testis barrier. Skin keratinocytes are responsible for formation of the skin barrier, but instead of working in a monolayer, keratinocytes differentiate into 4 different epidermal layers with the top corneal layer acting as the barrier . N/TERT-1 cells are skin keratinocytes and are what were used for epidermal monolayer cultures in this work. We used these cells as a general model to study PFAS effects, but the implications of PFAS toxicity on epidermal skin cells are important in understanding PFAS absorption through the skin and the dangers it might cause to human health. The study of PFAS effects on skin tissue and cells is lacking with only a few investigations completed thus far using human tissue engineered skin and animal models. PFAS was previously deemed to be not well absorbed through the skin by the US Environmental Protection Agency in 2002, but since then, it has been demonstrated that after topical exposure, PFOA permeates human tissue engineered skin, human and rat skin explants , and mouse skin. In the mouse studies completed by Franko et al., it was demonstrated that there were dose-responsive increases in serum PFOA after dermal exposure and concluded that PFOA is dermally absorbed. Han et al. showed that after 6 days of dermal exposure to PFOA , there was decreased skin thickness and portions of degeneration in the epidermal layers and necrotic fibroblasts in human tissue engineered skin but did not observe decreases in cellular viability.

They also demonstrated that after 2 weeks of dermal exposure in rats with another type of PFAS, short-chain perfluoroalkyl carboxylic acids rather than long, there were adverse effects on kidney, liver, testes, and skin that resulted in death via ulcerative dermatitis at application sites with high doses . Our findings of PFAS toxicity and cytoskeletal dysregulation on N/TERT1 cells support the need for more research on dermal absorption of PFAS. Previous investigations have concluded that tubulin acetylation plays a role in cell migration and cell development and it has been concluded that alpha tubulin acetylationhelps to protect microtubules against mechanical stress and enhance microtubule flexibility. Acetylation of alpha tubulin is a common post-translational modification of alpha tubulin that happens on stable microtubules. Disrupted acetylation process can contribute to negative effects in cell polarization, cell division, adhesion, motility and have been linked to neurodegenerative disorders and tumor metastasis. To our knowledge, no studies have investigated tubulin acetylation specifically in regards to PFAS toxicity. The work presented here demonstrates dysregulation of acetylated tubulin by differences in localization within N/TERT1 cells and further implicates PFAS as a cytoskeletal disrupter. These underlying roles of tubulin acetylation and f-actin and the consequences of dysregulation may be involved in the developmental changes of children and metabolic/reproductive toxicity changes in adults Many studies have focused on YAP localization and Hippo signaling regarding organ size and development.

YAP and its upstream regulators have been investigated in liver, pancreas, intestine, kidney, lung, and bone but regulation through the Hippo pathway is different in each system. Disruption of YAP localization can cause several developmental problems in many organs. Notably, deletion of YAP in the lung epithelium of mice and humans was shown to cause defective lung development; correct YAP localization in the cytoplasm is required for proximal airway maturation while nuclear YAP is required for progenitor specification. In the mouse kidney, deletion of YAP led to hypoplastic kidneys, fewer glomeruli, and defect formations in distal tubules and loop of Henle YAP is essential for nephron development and establishing kidney morphology and function. YAP knockout has also been found to decrease bone formation and increases bone marrow fat331. The pancreas and liver have been a focus of Hippo signaling pathway and organ development research. Rather than YAP knockout and upregulation, the Hippo pathway was altered via deletion/knockout of Mst1/2 in the pancreas324 and deletion of Mst1/2 and Lats1/2 in the liver. Changes in the levels of Hippo pathway regulators MST and LATS and their effect on organ size poses other mechanisms of organ development dysregulation; in which Hippo is inactivated and nuclear YAP is upregulated. These too could be causes of changes in organ mass and body weight decrease during infancy and in mice have been shown to be a cause of decrease in pancreatic mass resulting in body weight differences. Although the current study did not investigate knockout of YAP and PFAS effects, these summarized studies suggest that perturbation of YAP localization and Hippo signaling pathway activity by PFAS can lead to organ developmental changes and possible decreased body weight due to changes in organ size/mass tied to developmental issues. To investigate the possibility that PFAS acts directly on the Hippo pathway effector, YAP, we studied localization of YAP in the cytosol and nuclei under PFAS exposure in the N/TERT-1 and ASC52telo cell lines. Through this work, data show that in N/TERT1 cells at the 72 h time point, expression of nuclear YAP increased for PFOS doses of 30 and 40 µM and PFOA doses of 100 and 125 µM. These data indicate that these PFAS chemicals regulate the Hippo pathway in N/TERTs through YAP/TAZ regulation. Because of the crosstalk between Hippo pathway and Rho/ROCK cytoskeletal perturbation, it is plausible that PFAS regulates Hippo through mechanosensing and extracellular matrix/focal adhesion changes that propagate through the Hippo mediator YAP/TAZ . At the 24 h time point in N/TERT-1 cells and at 48 h in ASC52telo cells, there were no differences in YAP localization.General mesenchymal stem cell polarization toward adipogenesis and osteogenesis is dependent on Hippo signaling and particularly related to YAP localization . Reduced expression of upstream regulators of YAP such as Lats1/2 inhibit Hippo signaling and promote in vitro adipogenic and osteogenic differentiation, proliferation, and migration of bone marrow derived mesenchymal stem cells . With increased nuclear localization of YAP, there is increased osteogenic differentiation. Conversely, with decreased nuclear localization of YAP there is increased adipogenic differentiation. Though we did not directly quantify YAP in mature adipocyte cells under PFAS exposure, to aid in the understanding of adiposity changes,snap clamps for greenhouse we explored PFAS’ impact on mesenchymal stem cell differentiation toward adipogenesis.

We found that some doses of PFOA and PFOS upregulated adipogenesis as measured by lipid droplet presence . qPCR results further support the finding that PFAS disrupts fat homeostasis, but instead of showing upregulation of fat markers, data shows down regulation of mRNA expressions of the adipokine leptin and no changes in Adiponectin . PFOA and PFOS upregulated adipogenesis indicated by lipid droplet analysis but the mechanism of action still requires more investigation especially in understanding the non-supporting mRNA expression results. One avenue that may elucidate changes in the adipogenic process is specifically investigating cytoskeleton changes that may occur when PFAS is present during adipogenesis. Here, we investigated cytoskeleton in pre-adipogenic ASC52telo cells under PFAS, but not changes during or after exposure through 19 days of differentiation. Cytoskeletal components are involved in the maturation and homeostasis of fat cells. Our findings that PFAS chemicals disrupt cytoskeletal stability in skin and pre-adipose cells lend support to previous literature and suggest that the upregulation of adipogenesis could be due to the cytoskeletal perturbations. Palanivel et al. found, in rat cardiomyocytes, that an increase in adiponectin induces cytoskeletal remodeling and increases membrane microvillar like protrustions and actin polymerization. It is clear that PFAS is effecting pre-adipose and adipose cells, but it is unclear whether or not PFAS upregulates adipokines in mature fat cells which then disrupt the cytoskeleton through rho/rock and/or if PFAS acts directly on the cytoskeleton or not at all. In their undifferentiated state, ASC52telos did exhibit cytoskeletal changes including increase of protrustions at the cell boarder, shifts in cytoskeletal component intensities and location, and dysregulation of fibers .This dysregulation may be contributing to the PFAS associated increased adolescent obesity. Further investigation on lipid profiles and hormonal changes due to increased adipogenesis should be explored to help in understanding prior observations regarding increased childhood adiposity and higher PFAS serum concentrations. The goal of this work was to better understand the mechanistic actions of PFAS on human cells specifically of their effect in altering the cell cytoskeleton and the Hippo signaling pathway. We investigated PFAS chemicals, PFOA and PFOS, for their effects on an adipose derived mesenchymal stem cell line and a keratinocyte skin cell line . In conclusion, these data support previous findings that PFAS chemicals affect cytoskeletal integrity of the f-actin and microtubules and have demonstrated this in the human skin keratinocyte cell line, N/TERT-1 and the adipose derived mesenchymal stem cell line, ASC52telo. We also investigated if PFOA and PFOS directly effect the Hippo signaling pathway modulator, YAP. Our results support a direct modification of YAP localization by PFOA and PFOS chemicals. Finally, to gain an understanding into the negative effects of PFAS chemicals on infant and adolescent body weight, we examined the adipogenic process under PFAS dosing. PFAS indeed upregulates the adipogenic process as quantified by presence of lipid droplets through ORO assays and qPCR. Key adipokines were dysregulated in dose-dependent exposure to PFOA and PFOS. Although more investigation is required in understanding how PFAS specifically acts to upregulate adipogenesis, we speculate that the cytoskeleton changes involved in adipogenesis are being dysregulated and aiding in dysregulation of fat maturation. These findings reinforce the need for more in depth detection and more stringent limitations of PFAS exposure to the public, particularly pregnant mothers and children. In the 1960s, the state of Punjab led in the adoption of new high-yielding varieties of wheat and rice. Production of these new varieties required innovations in the use of fertilizer and water, which occurred in a complementary manner to the innovation in seed choices. Mechanization of several aspects of farming also became a supporting innovation. Agricultural extension services based in Punjab’s public universities guided farmers in their transition to the new modes of production. Furthermore, an infrastructure of local roads and market towns had been developed by the state government: these, along with central government procurement guarantees, gave farmers access and security in earning income from their produce. In the private sector, new providers of seeds and fertilizer, as well as farm equipment and equipment maintenance services also arose. All of these conditions together created what has been known as the Green Revolution economy. With the Green Revolution, Punjab quickly became the state with the highest per capita income. This ranking persisted into the 1990s, but underlying conditions became less favorable well before then. Gains in agricultural yields and productivity slowed, due to diminishing returns. While India began to grow faster after trade and industrial policy liberalization of 1991 and subsequent creeping reforms in other sectors, agriculture remained locked into the old policies, and Punjab mostly into the old equilibrium.