Working Papers
Economics of Anaerobic Soil Disinfestation in Strawberry Production
Co-authored with Rachael Goodhue
Abstract
Growers face increasingly stringent regulatory restrictions on the use of pre-plant soil fumigation, a crucial input in many fruit and vegetable farming systems, driving a search for effective non-chemical alternatives. Anaerobic soil disinfestation (ASD) has emerged as a promising strategy for managing soilborne pests and pathogens in strawberry production. This study evaluates the economic viability of ASD in strawberry farming using partial budget analysis and data from field trials conducted in California during the 2021–2022 and 2022–2023 seasons. Our analysis compares net returns (gross revenues minus analyzed costs) across ASD treatments and control plots, with and without chemical fumigation. Results from the 2021–2022 trial reveal no meaningful difference in yields from ASD-treated plots compared to control plots. Findings from the 2022–2023 trial show that ASD treatments significantly increased strawberry yields relative to non-fumigated control plots but yields from ASD with fumigation plots did not significantly differ from fumigated control plots. High ASD material, labor, and fumigation costs and low yields in the 2021–2022 trial resulted in negative and significantly smaller net returns from ASD treatments relative to the control. In the 2022–2023 trial, high yields among ASD plots resulted in positive net returns, but ASD treatment costs remained impractically high, leading to meaningfully smaller net returns from ASD treatments compared to the controls.
How Effective is Pesticide Regulation? Evidence from the Groundwater Protection Program
Co-authored with Brittney Goodrich
Abstract
When market-based instruments are impractical for addressing agricultural non-point source pollution, economists recommend regulations that incorporate farm management practices and environmental services to mitigate pollution. In this paper, we examine the adjustments farmers make to their pesticide programs in response to a policy delineating two types of regulated regions that differ in the required practices for pesticide usage based on local environmental conditions. Empirically, this study addresses the Groundwater Protection Program, which created a natural experiment through abrupt and uneven changes in the regulations governing the application of seven pesticides. Utilizing twenty-five years of field-level data, we estimate the program’s impacts on the use of regulated active ingredients and the consequent environmental effects in the perennial crops almonds, citrus, and grapes using a difference-in-differences regression framework. Our analysis reveals that the program led to meaningful reductions in the use of regulated active ingredients in fields in regulated regions, but the effects varied substantially across crops. To test if growers replaced regulated ingredients with alternative pesticides, we examine the impact of the program on the environmental impact—an index that considers the potential harm of pesticides to water systems, human health, and wildlife—of alternative active ingredients per planted acre and find no significant effects. In a final set of regressions, we use the environmental impact of regulated and alternative active ingredients per planted acre as our dependent variable and find that the program led to significant reductions in citrus orchards and grape vineyards but no change in almond orchards.
The Impact of Land Use on Water Quality: Evidence from California Wells
Co-authored with Pierre Mérel and Jeffrey Hadachek
Abstract
Nitrate pollution threatens human health and ecosystems in many regions of the world. Although scientists agree that nitrogen compounds from human activity, notably agriculture, enter groundwater systems, empirical estimates of the impacts of land use on nitrate concentrations in well water are still lacking. We provide evidence of such impacts by combining nitrate concentration measurements from 6,016 groundwater wells with remotely sensed California land use data from 2007–2023. Results show that a 10 percentage point increase in the share of land used to grow high nitrogen hazard index crops within 500 meters of a well relative to undeveloped land is associated with a 12% increase in nitrate concentrations, while the same increase in low-intensity urban development is associated with a 10% increase. Local cattle populations also contribute to nitrate pollution. However, conditioning on initial nitrate measurements, we find limited evidence that human activity affects nitrate concentrations a decade later.
Does Mating Disruption Decrease Insecticide Use? Evidence from Navel Orangeworm Management in California Tree Nut Orchards
Co-authored with Brittney Goodrich.
Excerpt
Navel Orangeworm (NOW) is the top pest in California almonds. Infestations damage nuts, reduce grower revenue, require costly management practices to control, and threaten food safety and exports because of its link to aflatoxin contamination (Campbell, Molyneux, and Schatzki 2003; Palumbo et al. 2014). Growers typically manage NOW with insecticide sprays and cultural controls, but uncertainty in the future pesticide regulatory landscape threatens to restrict the chemical tools growers can use. In recent years, NOW mating disruption has emerged as a promising new pest management technology in tree nut production. Mating disruption uses pheromones to confuse adult NOW moths, interrupt mating patterns, and reduce the number of larvae that can go on to damage nuts. Results from recent experiments in Central Valley almond orchards show about a 50% reduction in nut damage when mating disruption is used in combination with synthetic insecticides compared to insecticides only (Higbee and Bucks 2021; Haviland et al. 2021). However, extension specialists and others recommend that growers use mating disruption in combination with synthetic insecticides and cultural controls (Haviland et al. 2023; Coatney 2019). In this paper, we answer the following questions. (1) To what extent do almond growers change the number of chemical pesticide applications targeting Navel Orangeworm in response to the use of mating disruption? (2) To what extent do almond growers change the grams per acre of active ingredients targeting Navel Orangeworm in response to the use of mating disruption? California tree nut growers face several production challenges going forward, including uncertainty in the pesticide regulatory landscape, labor and fuel costs, and the effects of climate change (Osteen and Fernandez‐Cornejo 2013; Pathak et al. 2018). Growers rely on innovations to address economic challenges, particularly costly pest pressures and state and federal regulations. This paper leverages pesticide-use data from the California Department of Pesticide Regulations, the most comprehensive dataset of pesticide-use in the world. In our econometric estimation, we use the spatial first difference method proposed by Druckenmiller and Hsiang (2019) in order to leverage variation in pesticide use between neighboring orchards.
Economics of By-Product Feeds in Dairy Rations, With Implications for Resource Use and Environmental Consequences
Co-authored with Jarrett Hart and Daniel A. Sumner.
Abstract
Spent grains and grape pomace are by-products of beer and wine production that, where economically feasible, are commonly used as animal feed. In California, they are most commonly used by local dairy farms, replacing feeds that require additional resources such as land and irrigation water. We quantify the substantial resource consequences of repurposing these by-products for use as feed for dairy cattle by estimating the land and water needed for replacement feeds. We also estimate the considerable environmental implications, in terms of greenhouse gas emissions, when these by-products are diverted to landfills.