Effectiveness of microbial indexes in discriminating interactive effects of tillage and crop rotations in a Vertic Ustorthens

Conservation tillage is a soil management practice able to reduce erosion, increase organic matter content and improve physical, chemical and biological soil properties, Conservation tillage reduces the incorporation of crop residues into the soil profile and minimises the exposure of humified organic matter to biotic and abiotic degradative processes. In this article the effect of conventional (ploughing at 40-cm depth coupled with harrowing at 20-cm depth) and reduced tillage (hat-rowing at 20-cm depth) and two rotations (vetch-oat/wheat and fallow/wheat) on biochemical and microbial properties of a Vertic Ustorthens, located in a semi-arid region of southern Italy, has been investigated. Tillage had a more pronounced effect on soil properties studied here than did rotations. By comparison to conventional tillage (CT), the reduced tillage (RT) resulted in improved soil C and microbial biomass content. Even though some of the selected enzymes showed seasonal variability and, when averaged across the sampling period, were not always able to discriminate among treatments, their sum showed a strong correlation with soil organic C and soil microbial biomass C (MBC), for all these parameters increased in RT plots.