Climate change, soil carbon sequestration, and agricultural technology adoption: the case of deeper root system corn adoption and diffusion in the U.S. Corn Belt
Date
2024
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Abstract
Traditional agricultural practices and land use changes have resulted in greenhouse gas emissions back into the atmosphere, which negatively contributes to climate change. Traditional practices also reduce soil organic matter including soil carbon which is essential for soil health, maintenance of soil biological processes, and environmental sustainability. Currently, a range of agricultural conservation practices has come to be recommended and incentivized for soil carbon sequestration by either increasing carbon inputs and/or reducing carbon losses. These include practices such as reduced tillage, cover cropping, and crop rotations. Although private carbon markets have taken the initiative to provide incentive payments for carbon sequestration in agriculture, the adoption of SCS practices can be hindered by different socioeconomic, farm operational, and environmental constraints. In addition to currently recommended soil management practices, new crop genetic innovations, including perennial grain crops and annual crops, such as corn, with larger root systems or deep root traits are emerging as additional examples of SCS frontier technologies. The first chapter of this dissertation utilizes a joint adoption model to hypothetically examine the impact of socioeconomic, environmental, and farm variables on the probability of adopting either or both of currently recommended SCS practices and these novel genetic innovations, such as deeper root corn varieties. Moreover, deeper root system traits are expected to maintain yields under drought conditions. Deeper root system hybrids are also expected to be an effective agricultural technology for maintaining soil health as they can reduce soil erosion and increase soil organic matter. Existing drought tolerant (DT) corn varieties that have been commercially marketed for more than 10 years exhibit some of these same characteristics. Therefore, the adoption of existing DT hybrids is likely a good indication of the potential for the adoption of hybrids with further enhanced root systems. In the second chapter, we use state-level and field-level data for corn planted in the United States Corn Belt to examine the influence of climate change, soil characteristics, and production practices in the decision to adopt DT varieties. Seed industry data indicates that 44 percent of Corn Belt planted corn acres were allocated to a DT variety in 2021 and 58 percent were planted to DT in 2022. Results suggest that exposure to recent years' drought is a significant determinant of the adoption of DT corn. DT corn is more likely to be adopted in non-irrigated fields. We find that western Corn Belt states are more likely to increase the share of DT corn acres compared to eastern and central Corn Belt states, associated with lower precipitation values and higher drought severity. Thus, deeper root varieties are likely to be more attractive to farmers in western more arid regions of the Corn Belt, where associated soil carbon benefits of deeper root varieties are likely to be more limited. Anticipating that enhanced deeper root corn hybrids with public benefits may come to be treated as a conservation practice included under incentive payment programs, and understanding that soil carbon potential is heterogeneous, in the third chapter we consider the question of spatial targeting of payments. We develop three per acre payment scenarios under the benefit optimization approach to estimate and compare the metric tons of carbon inset under an optimal cropland acre enrolled in a carbon incentive program. The study uses cross section data for counties in the United States Corn Belt, a region with the largest number of productive cropland acres and higher potential carbon sequestration rates compared to other regions across the United States. Results show that if the carbon incentive program is designed to target the adoption of SCS practices that result in high, medium, and low SCS rates respectively, then we can expect that about 32, 24, and 19 million metric tons of carbon can be sequestered in Corn Belt croplands annually.
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Embargo expires: 05/20/2026.
Subject
soil carbon sequestration (SCS)
agricultural technology adoption
conservation practices
carbon market
deeper root
corn
joint adoption decision
DT corn
drought severity
spatial targeting