Effect of crop rotations and cultural practices on soil organic matter, microbial biomass and respiration in a thin Black Chernozem

Abstract

The effects of crop rotations and various cultural practices in a Rego, Black Chernozem with a thin A horizon were determined in a long-term study at Indian Head, Saskatchewan. Generally, fertilizer increased soil organic C and microbial biomass in continuous wheat cropping. Soil organic C, C mineralization (respiration) and microbial biomass C and N increased with increasing frequency of cropping and with the inclusion of green manure or hay crop in the rotation. The influence of treatments on soil microbial biomass C was less pronounced than on microbial biomass N. The treatments had no effect on specific respiratory activity; however, it appeared that the microbial activity, in terms of respiration, was greater for systems with smaller microbial biomass. Changes in amount and quality of the soil organic matter were associated with estimated amount and C and N content of plant residues returned to the soil. -from Authors