The short term influence of aboveground biomass cover crops on C sequestration and β-glucosidase in a vineyard ground under semiarid conditions

Abstract

Tillage and semiarid Mediterranean climatic conditions accelerate soil organic matter losses in Spanish vineyards. Previous studies showed that cover crops can increase soil organic carbon (SOC) in Mediterranean vineyards. The objectives of this study were to evaluate the influence of two different cover crops in the short term on soil C sequestration in a semiarid vineyard and to study the potential use of both β-glucosidase enzimatic activity (GLU) and the GLU/SOC ratio in order to assess the SOC increase. The experiment was carried out in a cv. Tempranillo (Vitis vinifera L.) vineyard on a Oxyaquic Xerorthent soil in Rioja winegrowing region (NE, Spain). The experimental design was established in 2009 with three treatments: conventional tillage; sown barley cover crop (Hordeum vulgare, L.); sown Persian clover cover crop (Trifolium resupinatum L.). Carbon in the aboveground biomass with each cover crop was monitored. Soil was sampled in June 2011 and June 2012, and SOC, GLU and the GLU/SOC ratio were determined. After 3 years both cover crops increased SOC at soil surface with C sequestration rates of 0.47 and 1.19 t C ha–1 yr–1 for BV and CV respectively. GLU and GLU/SOC ratio increased in both cover crops at 0-5 cm soil depth. The C sequestration rates and GLU were related to the cover crops aboveground biomass. In consequence, in semiarid vineyards under cover crops GLU could be an appropriate indicator to asses the increase of SOC and the soil quality improvement in the short-term (2-3 years).