Impact of Years of Enrollment in the Conservation Reserve Program on Depth of Rain Infiltration

Abstract:

The Conservation Reserve Program (CRP) is a USDA program administered by the Farm Service Agency (FSA) introduced in 1985 to reduce soil erosion by increasing vegetative cover of highly erodible land. The Texas High Plains (THP) leads the US with >890,000 ha enrolled in CRP. Potential benefits of the CRP include, e.g., increased infiltration of rainfall and organic matter, and better soil structure. However, impact of these benefits is not well characterized. Participation in the CRP is done via contracts (10-15 years in length) and since its inception land area of the THP enrolled in CRP has varied significantly allowing the evaluation of years of enrollment (age) on soil structure and impact on rain infiltration. This information is critical for land users to determine how long it is necessary to enroll their land in the CRP to improve soil structure and impact rain infiltration and increase the water holding capacity of the soil. Stable isotopes of water present a useful technique that is used in ecology and hydrology to study water movement through ecosystems and can be used to evaluate the depth of infiltration of rainwater under CRP management. We compared the infiltration depth of rain in land under CRP management to land under continuous dryland cotton with no irrigation. Two locations, in Terry and Lynn counties, were used for this study. The site in Terry County was enrolled in CRP for 25 years (1985) and 22 years (1992) in Lynn County.