Soil microbiological properties and its stratification ratios for soil quality assessment under different cover crop management systems in a semiarid vineyard

Résumé

In vineyards in Spain, tillage and semiarid Mediterranean climatic conditions accelerate organic matter loss from the soil. Cover crops are a conservation management practice that can provoke changes in soil quality which requires evaluation. Stratification ratios of soil properties such as soil organic C and labile C fractions have been proposed for the assessment of soil quality under different soil management systems. Our objective was to study the effect of different cover crop management on various soil parameters and their stratification ratios. We evaluated three different soil managements in a Typic Haploxerept from NE Spain: conventional tillage (CT); 5-y continuous cover crop of resident vegetation (RV); and 4-y continuous cover crop of Festuca longifolia Thuill., followed by 1-y Bromus catharticus L. after resowing (BV). We monitored soil organic C, particulate organic C, water soluble C, potentially mineralizable N, microbial biomass C, β-glucosidase and urease enzymatic activities, and water stable aggregates at 0-2.5, 2.5-5, 5-15, 15-25, and 25-45cm soil depths. We calculated soil depth stratification ratios of those soil properties. Resident cover crop increased microbiological properties, labile C fractions, and aggregation with respect to conventional tillage at 0-2.5 and 2.5-5cm soil depths. However, for Bromus cover crop the same soil properties were lower than for the resident cover crop at 0-2.5cm depth. Stratification ratios of β-glucosidase and urease enzymatic activities, and particulate organic C showed a higher sensitivity than other soil properties; therefore, they would be the best indicators for soil quality assessment in semiarid Mediterranean vineyards. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.