Effects of Prairie Restoration on Soil Quality Indicators.

Characterization of soil ecosystem functioning based on soil quality assessments of native prairie may provide a reference for evaluating improvement in soil quality of cultivated agroecosystems converted to perennial vegetation during prairie restoration. Our objective was to determine the effect of prairie restoration on several soil quality indicators relative to native prairie and cropland sites within the loess/glacial till prairie landscape in central Missouri. Soil was collected from the 0-10 cm depth from sites with contrasting management: native prairie, restored prairie for 10 and 18 yr, conservation reserve program (CRP) for 18 yr, and long-term row crop cultivation (>50 yr) during 2004-2007. Soil organic C (SOC), total N, water-stable soil aggregates (WSA), saturated hydraulic conductivity, and soil enzyme activities were consistently higher in native prairie, intermediate in restored prairie and CRP, and lower in cropland sites over the four-year study period. SOC strongly influenced biological activity, illustrated by significant correlations with glucosidase activity (r² = 0.83) and WSA (r² = 0.82). The increases in microbial properties during prairie restoration likely reflect increases in vegetative and root biomass, which contributes high amounts of soil C and directly influences microbial activity. The soil quality indicators selected for this study were sensitive for detecting changes in soil ecosystem functioning and should be effective in evaluating the long-term impact of prairie restoration.