Influence of pasture management on soil biological quality

The long-term sustainability of pasture management systems, whether related to structural stability or nutrient dynamics, is dependent upon maintainin g soil biological properties. This study investigates the extent to which t he microbiological and biochemical properties of soil can change with seaso n and pasture management system, including their likely value as indicators of soil quality. The experiment was conducted on a 30-ha pasture near Bran don, Manitoba, Seasonal fluctuations were observed in the soil microbial an d biochemical properties. In general, these fluctuations were mainly indepe ndent of the small variations in soil organic matter content but were more closely related to soil water content. The data also suggests an impact of stocking rate and grazing system on soil microbial biomass C and on N miner alization potential. However, because duration of the investigation, limite d number of replications and the high soil variability encountered, it is n ot yet possible to recommend any particular grazing system and/or stocking rate favorable for the maintenance of soil biological quality. The trends s uggest that light, continuous grazing systems had the largest microbial bio mass and nutrient mineralizing activity.