Research

Promoting Cover Crop Use in the United States: The Role of State-led Incentive Programs

with Roderick M. Rejesus

This study examines the role of state-led conservation programs in promoting cover crop adoption in the United States (US). Utilizing county-level satellite data on cover crop acres from 16 US states between 2005 and 2020, our study employs a staggered difference-in-differences (DiD) framework to estimate the impacts of these programs on cover crop uptake. The findings reveal that state programs significantly increase initial short-term adoption of cover crops. However, there is evidence that the strong initial adoption impact of state programs is generally not sustained over the longer term several years after the introduction of the state program. Bolstering state-level conservation programs offers a practical pathway to accelerate cover crop adoption rates and meet environmental goals in the short-term, especially since these programs are flexibly designed and tailored to local needs. Nonetheless, program design adjustments or new policy instruments may be needed to sustain further adoption over the long-run.

Yield and Economic Impacts of Enhanced Efficiency Nitrogen Fertilizers: Evidence from a Bayesian Meta-Analysis

with Roderick M. Rejesus and Alex L. Woodley

This study employs a Bayesian meta-analysis to evaluate the yield and economic impacts of four major categories of enhanced efficiency nitrogen fertilizers (EENFs) within North American corn production systems—nitrification inhibitors (NIs), urease inhibitors (UIs), dual inhibitors (DIs), and controlled release fertilizers (CRFs). The analysis synthesizes data from 60 field experiments, revealing an average yield increase of 3.24% for corn produced with EENFs compared to conventional nitrogen fertilizers. All EENF types performed better under management conditions prone to nitrogen losses. NIs were particularly effective in fine-textured soils, UIs in coarse-textured soils, while DIs exhibited inconsistent yield improvements across most conditions. Economic analysis indicated that NIs and UIs generally lead to positive net returns, while DIs and CRFs presented mixed profitability outcomes. The variability in yield and profit outcomes from using the different EENFs may be the reason for the relatively low adoption levels observed in the United States (US). This research provides critical insights into the potential viability of some EENF types for sustainable agriculture, underscoring the need for better understanding and communicating their economic and agronomic advantages to facilitate further adoption. The findings serve as valuable guidance for policymakers and farmers aiming to optimize nitrogen fertilizer use while enhancing agricultural productivity and environmental sustainability.

Evaluating the Impact of Pandemic Cover Crop Program on Cover Crop Adoption

Optimal Control of Joint Soil Capital and Groundwater Stock

with Zachary Brown

This work-in-progress investigates the dynamic interactions between soil capital accumulation and groundwater use in agricultural systems. Employing an optimal control framework, the study models how farmers can maximize the net present value of farm profits by balancing the short-term economic benefits of irrigation with the long-term sustainability of soil health through cover crop adoption. The model explicitly captures feedbacks among soil quality, water availability, and farm profitability under both socially optimal and open-access groundwater management regimes. Preliminary results indicate that the likelihood of cover crop adoption under open-access conditions depends on the trade-off between short-term substitutability, which reflects competition for water between cover and cash crops, and long-term complementarity, where improvements in soil capital enhance water-use efficiency and crop productivity. Future work will extend the model using stochastic dynamic programming and numerical simulations to account for uncertainty in rainfall, groundwater recharge, and crop yields.