Submitted to: Pacific Northwest Sustainable Agriculture Newsletter
Publication Type: Trade Journal
Publication Acceptance Date: April 28, 2009
Publication Date: May 1, 2009
Citation: Kennedy, A.C. 2009. CRP Takeout: An Excellent Opportunity to Begin Direct Seeding. Pacific Northwest Sustainable Agriculture Newsletter. Interpretive Summary: As growers approach the end of Conservation Reserve Program (CRP) contracts, they are faced with the decision of how to manage these lands as they return to crop production. We assessed changes in soil quality with conservation and conventional tillage practices on lands that were eligible to return to crop production after ten years of enrollment in CRP. When tillage was used, soil quality quickly changed in the first year. Soil organic matter fractions were degraded and lost to the air as CO2. In plots with multiple tillage passes, soil organic matter fractions and pH were lower after only one year compared to CRP land. We found that conventionally managed fields not only resulted in organic matter decline, but nutrient and water contents were lower; soil microbial communities shifted away from those found in CRP; water infiltration decreased; and the amount of soil vulnerable to water and wind erosion increased. We found that the soil quality of direct seed CRP was more similar to the original CRP with respect to pH, soil enzymes, the soil microbial community and organic matter fractions than tilled CRP. Direct seed management enhances soil quality and maintains soil quality in lands previously enrolled in CRP.
Technical Abstract: Lands returning to production after enrollment in CRP can be managed to maintain the many improvements in soil quality that have occurred over the life of the CRP contract, such as higher organic matter, increased water infiltration and improved soil structure. Direct seeding may be a viable management option to preserve soil quality as CRP lands are returned to crop production. We assessed changes in soil quality with no till and conventional tillage practices in lands that were eligible to return to production after ten years of enrollment in CRP. Soil quality quickly changed for the worse with excessive tillage in the first year. Soil organic matter fractions declined and were lost to the atmosphere as CO2. In conventionally tilled plots, soil organic matter fractions and pH were lower after one year compared to CRP land. In additional studies, we found that tillage resulted in a decline in organic matter, lower nutrient and water contents; a shift in soil microbial communities away from those found in CRP; decreased water infiltration; and an increase in the vulnerability of soil to water and wind erosion. We found that the soil quality of direct seed CRP was more similar to the original CRP with respect to pH, soil enzymes, the soil microbial community and organic matter fractions than tilled CRP. To maintain the soil quality of CRP, use direct seed to minimize disturbance to the soil and keep the residue on the land.