The pesticide products used in organic agriculture are generally less toxic, but their reduced efficacy could drive higher application rates, which makes the overall environmental impact of organic agriculture less obvious. In fact, certain pesticides used in organic agriculture have been found to be more toxic than conventional pesticides targeting the same pest . In Läpple and Van Rensburg , the authors found that farmers who entered organic production after the supporting policy was launched are more likely to be profit-driven and less environmentally concerned than farmers who began organic production before any supporting policy was in place. Therefore, studying pesticide use in organic agriculture and how it changes can expand the understanding of organic agriculture and its future. The consolidation into larger operations is another important issue for organic agriculture because it could undermine the perception of organic agriculture as environmentally friendly. Although both the number of organic farms and total organic acreage has increased, blueberry package consolidation still exists if large farms grow faster than small farms.
Meanwhile, the consolidation process had been clearly documented for the organic food processing sector and U.S. agriculture in general . Farm size, measured in acreage, was found to be positively correlated with pesticide use for staple crop productions in the previous literature for conventional agriculture . If this relationship also applies to organic agriculture, then cropland consolidation could have a negative impact on the environment, which means that organic agriculture could become less environmentally friendly than it used to be as the consolidation proceed. I find that the farm size is positively associated with use of sulfur and fixed copper pesticides in the organic crop production. Organic agriculture in California has a diverse crop portfolio, which affects farm size and pesticide use simultaneously. Certain crops are produced in a large scale, measured in acreage, and require intensive pesticide use. How changes in the crop mix interact with the consolidation process is another issue investigated in this essay. The objective of this essay is threefold: to identify organic fields in the PUR database using historical pesticide use records; to characterize the patterns and trends of production and pesticide use for those identified organic fields collectively by crop, crop acreage, year, farm size, and other attributes; to assess the environmental impacts of pesticide use in organic agriculture and the consolidation of organic cropland.
For each agricultural pesticide application, the PUR database specifies the location of application in the variable “COMTRS”, which stands for the county, meridian, township, range, and section as defined by the Public Lands Survey mapping system . This information allows us to locate which section does the field belong and aggregate pesticide usage at the 1×1 mile PLSS section-level, which is the finest spatial scale reported in the PUR database. This detailed section-level analysis of the spatial distribution of organic fields in California and, how it has changed over time, is only possible using my method for identifying organic production fields in the PUR database. In the PUR database, acreage information is recorded as both treated acreage and planted acreage. The former represents the acres physically treated in a pesticide application while the latter remains constant for the field within a year. However, researchers have demonstrated that planted acreage in the PUR database is not consistently reliable for annual crops . So, in this essay, we use the maximum treated acreage in a given year as the acreage for each field for annual crops. This approach assumes that the entire field is treated with pesticide at least once per year. If this assumption is invalid, then the planted acreage will be under counted. As presented below, the validity of this approach is supported by the consistency of state-scale crop acreages that are generated from the PUR database with those from other data sources. One caveat of the PUR database for organic production is that since 2000, pesticide products deemed as having “minimum impacts” are no longer required to be registered with CDPR, which exempts them from the pesticide use reporting requirement. A detailed list of these pesticide ingredients can be found in the California Code of Regulations section 6147 .
Most ingredients exempted from registration are natural or naturally-derived products , which could presumably be used in organic agriculture and have impacts on the surrounding environment. However, these exempted ingredients are not widely applied, based on their minimal amounts of usage in the PUR database prior to 2000 when they were still required to be reported. Therefore, this issue is not likely to invalidate the results, especially because the number of fields where only such ingredients were applied before 2000 is small. For convenience, some chemically-related individual active ingredients were grouped together, such as combining the many different strains of Bacillus thuringiensis, which target different insects and are each treated as a distinct AI in the PUR database, into a single “microbial” group. A detailed list of microbials is available in the appendix. The group of “Copper, fixed” includes the summation of copper, copper oxychloride, copper octanoate, copper oxide, and copper hydroxide; and the two forms of copper sulfate .Organic growers are required to comply with a set of crop management standards, regarding seeds and planting stock practices, soil fertility and crop nutrient management, pest, weed, and disease management, and crop rotation among others . The most relevant requirement for this essay is that there is a 36-month transition period between the last application of any prohibited substance under organic regulations and of- ficially recognized organic production. The field identification method relies on this requirement. First, we constructed a list of allowed and prohibited substances based on various sources . Second, we checked each field in the PUR database, to see which AIs were applied over the previous three years. If there were no applications of any prohibited ingredients, then the field was considered organic as of that year. Organic growers who do not use any chemical tools at all to manage pests and weeds are missing from the PUR database entirely, and therefore not identified in this essay. However, blueberry packaging based on acreage comparisons between the PUR database and other data sources, those growers appear to operate a very limited number of acres. A field could comply with the pest, weed, and disease management standards of the NOP while violating other standards and still not qualify for organic production. Because the PUR database only contains pesticide use information, my method cannot distinguish such fields from actual certified organic fields. On the other hand, growers could follow organic farming practices but choose not to certify their fields for various reasons. However, as mentioned above, the amounts of acreage in these categories must not be very substantial because the PUR-derived organic crop acreages agree with those from CAC compiled sources, suggesting that my method is valid. One caveat of this method is the consistency of field information in the PUR database from year to year. As mentioned previously, the “SITE_LOCATION_ID” on pesticide permits, a number chosen by growers or assigned by county, indicate a physical field location, but the id number may change from year to year. When that ID does change, a new “field” appears in the PUR database for which we do not have information on its historical pesticide applications. In this situation, we assume for annual crops that the land was fallow before a new “SITE_LOCATION_ID” was assigned. This assumption could cause us to overestimate the total organic acreage somewhat, by including fields with a new “SITE_LOCATION_ID” which may have had prohibited substance applications in the past three years. Pasture and rangeland have unique pest management practices and enormous acreage, but they are not covered in this essay as they do not suit my primary purpose of evaluating the environmental impacts of pesticide use in organic crop fields.
For pesticide applications on the identified organic fields in the PUR database, the PURE index was used to assess the potential environmental impacts for five environmental dimensions: surface water, groundwater, soil, air, and pollinator . The PURE index is calculated for five different environmental dimensions: surface water, groundwater, soil, air, and pollinators. For dimensions other than air, index values are calculated based on predicted environmental concentrations and standard toxicity values for relevant organisms. The algorithm used to calculate the predicted environmental concentrations includes the site-specific environmental conditions , which is a major advantage over other indices for assessing the environmental impacts of pesticide use, such as the Environmental Impact Quotient . The predicted environmental concentrations have been proven to align with monitoring data in a previous study . The index value for air is calculated using the predicted volatile organic compound emissions of each pesticide product. Individual index values are normalized to range from 0 to 100 . The PURE index values are calculated for each AI in each pesticide application for each field. These disaggregated index values are then summed at the field level to provide a general index value assessment for each field. To evaluate the overall impact for each crop, an acreage-weighted average across all relevant fields can be determined. This aggregation can be taken one step further, across all AIs, to show the potential impact for all pesticide use using the same aggregation process for organic and conventional fields.Measures of State-specific total organic acreage from different data sources are compared for all seven crops/crop groups available in the USDA organic certification and survey data plus strawberries from the CSC survey data . Among these eight crops/crop groups, four of them are annual and the others are perennial crops. Their organic acreage is plotted in Figure 2.2 and Figure 2.3 below. As mentioned previously, then data sources have different reporting requirements and discrepancies can be caused by a variety of reasons that apply to all crops. In the CDFA registration data, new organic growers report their expected acreage for the next year. If growers decide not to engage in that expected organic production, their registration records remain in the system, which could produce an inaccurate inflation in acreage data, especially for crops that went through a rapid growth of organic production. Growers with less than $5,000 annual organic sales are required to register their production with CDFA but do not have to apply for organic certification. So their acreage might not be counted in USDA data. Both USDA and CDFA data relies on a set of well-defined organic standards and restrictive regulations, which did not exist before 2001. For perennial crops, new registrations with CDFA or new certifications with USDA must include the documentation of orchards before they are fully established . Therefore, we observe new orchards and vineyards in the USDA and CDFA data before they enter the PUR database. If growers adopt the organic pest management program but do not market their products as organic, their acreage is only covered in the PUR database, not the others.Meanwhile, discrepancies in acreage are caused by crop specific reasons. For lettuce , USDA has consistently reported higher acreage values since 2004. In 2016, the lettuce acreage from the USDA organic survey is more than double the acreage from the CDFA registration data . One reason could be potential double or multiple cropping of lettuce in one calendar year. When growers harvested lettuce multiple times from the same field, USDA reported the sum of acres for each harvest while CDFA asked for the size of the field. My method accounts for this phenomenon by counting days between the first and last pesticide applications. Normally, both leaf and head lettuce require at most 130 days from planting to harvest in California . So if two pesticide applications occur more than 130 days apart for the same field, we assume that the lettuce was harvested twice and the acreage would be doubled. After this adjustment, the PUR database still falls short of the acreage documented in the USDA dataset but is in-between the other two sources since 2003. Before 2003, CDFA had more acreage than the other data series because the crop category “lettuce, salad mix”, which contains arugula, red/green mustard, and other crops , used to be reported as lettuce. For strawberries , the CSC data always show somewhat less acreage because their data are derived from surveys and the survey response rate is not reported. For apples , the organic acreage is small compared other perennial crops, which amplifies the potential measurement errors.