Effect of long-term monoculture on microbiological and biochemical properties in semiarid soils

The effect of continuous monospecie cropping on the microbial activity of a rable semiarid soils was studied. Soil cultivation reduced organic carbon a nd humic substance contents, The total carbohydrate content was little infl uenced by the type of monospecie whereas the water-soluble carbohydrate and soluble carbon content were affected. The soils with unirrigated crops sho wed the lowest values of microbial biomass carbon and basal respiration. Th e high qCO(2) values suggest a certain instability of the arable soils. In general, monospecie cropping in semiarid areas had a negative effect on enz ymatic activities particularly in soils where unirrigated crops were grown. The soils dedicated to monospecie cropping showed lower values of microbio logical and biochemical properties than native soils.