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Under semiarid Mediterranean climatic conditions, scarce attention has been given to the utilization of permanent cover crops (PCCs) in vineyard agroecosystems to increase soil organic C (SOC) and to improve the soil quality. We evaluated the feasibility of two permanent cover crops (resident vegetation, RV, and ‘Aurora gold’ blue fescue [Festuca longifolia Thuill.] vegetation, FV) to increase SOC and to improve the soil quality with respect to conventional tillage in a semiarid vineyard. We studied the influence of these management practices on the labile organic matter fractions (particulate organic C [POC], potentially mineralizable N [PMN], and water‐soluble C [WSC]), on the water aggregate stability (WAS) and on the stratification ratios (SRs) of these soil attributes. The field experiment was conducted on a fine‐loamy, mixed, thermic Typic Haploxerept soil in a vineyard located in the La Rioja region (northeast Spain). Soil samples were collected from four soil layers (at depths of 0–2.5, 2.5–5, 5–15, and 15–25 cm) during June 2008, 4 yr after cover crop establishment. The SOC content, POC, WSC, PMN, and WAS were measured. At a depth of 0 to 2.5 cm, the cover crops increased SOC, POC, WSC, PMN, and WAS. The C sequestration rates for RV and FV were 1.34 ± 0.31 and 1.52 ± 0.70 Mg ha−1 yr−1, respectively. Regression analyses indicated positive strong correlations among all parameters monitored. The SRs of the SOC, POC, and PMN were >2 in all depth ratios calculated and therefore were efficient indicators of the soil quality improvement caused by the PCCs. In a semiarid Mediterranean vineyard, a PCC has proven to be an effective strategy to enhance the SOC and to improve the soil quality in the short term.

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Aim The aim was to study the effects of two different cover crops (leguminous versus gramineous) on soil NO 3 − -N availability, grapevine N status, and yeastassimilable N (YAN) and amino acid profile in the must of a cv. Tempranillo vineyard from La Rioja (Spain) over 3 years.Methods Three treatments were established: gramineous (barley) and leguminous (Persian clover) cover crops and conventional tillage. Soil total N and extractable NH 4 + -N at bloom, soil NO 3 − -N content from budbreak to postharvest, leaf N content at bloom, and free amino acids and ammonia in must were monitored.Results Each year, the barley cover crop treatment had lower soil NO 3 − -N than tillage, while the clover treatment showed lower soil NO 3 − -N than tillage in 2009 and showed higher values in 2010 and 2011. In 2011 leaf N content, yeastassimilable N (YAN), and some amino acids in the grapes were lower in barley cover crop treatment thus affecting the amino acid profile. Meanwhile, the clover cover crop did not have these effects. Furthermore, relationships between leaf N content and various amino acids were also found.Conclusions With the barley cover crop treatment, soil N availability decreased from the first year of the experiment, provoking a decrease in N grapevine status and in content of YAN and various amino acids at the third year. In contrast, clover cover crop maintained N grapevine status, YAN, and amino acid profile similar to conventional tillage. Therefore, our study shows how soil N can be managed both within a year and from year to year when two different cover crops are sown and how the grapevine N nutritional status and YAN content and amino acid profile can be modified in the must.