Tillage and fallow effects on selected soil quality characteristics of former conservation reserve program sites

ABSTRACT:

Tillage and fallow have been suggested as management options for converting Conservation Reserve Program (CRP) areas to cropland. This study was conducted to measure selected soil quality characteristics of fomer CRP sites in Mississippi, Nebraska, and South Dakota that were tilled and then left fallow for 21 or 22 months. Soil samples from depth intervals of 0–7.6 cm and 0–30.5 cm were collected for laboratory assessment of the following soil quality indicators: bulk density, EC, pH, total C, organic C, total N, NO₃-N, NH₄-N, PO₄-P, biomass C, biomass N, anaerobic NH₄-N, lab respiration 0–10 days, and lab respiration 10–20 days. When compared to undisturbed CRP, increased NO₃-N values on the tillage and fallow plots suggest that under the extreme conditions employed in this study, organic residues were being mineralized. As a result, significant reductions in organic C and total N were found at the 0–7.6 cm depth on each of the fallow plots. Thus, to reduce soil quality degradation, use of minimum-till or no-till management systems may be best suited for CRP areas which are converted to cropland.