Soil quality changes in eastern Washington with Conservation Reserve Program (CRP) take-out

ABSTRACT:

CRP lands in eastern Washington were eligible for dryland cropping production as of 1995. Conservation and conventional take-out practices were assessed at eight sites throughout eastern Washington to determine changes in soil quality parameters. The trials tested different tillage options: direct-seed/spring plant (DSP), conventional tillage/spring take-out (CSP), or conventional tillage/summer fallow (CSF). The eastern Washington sites range in annual precipitation from 23 to 36 cm (?? to ?? in) and in soil organic matter from 1.06 to 2.60%. Microbial biomass, readily-mineralized carbon (RMC), dehydrogenase activity, pH, organic matter content (OM), nitrate and ammonium concentrations, moisture, bulk density, and aggregate stability were monitored from 1995 to 1996. Results showed that RMC and pH were lower after one year in conventionally-tilled plots as compared to CRP grassland. The direct-seed samples were more like CRP grassland with respect to pH, dehydrogenase activity, and RMC than conventional tillage treatments.