SOIL CONSERVATION BENEATH GRASS COVER IN HILLSIDE VINEYARDS UNDER MEDITERRANEAN CLIMATIC CONDITIONS (MADRID, SPAIN)

The use of plant cover for soil protection in Mediterranean hillside vineyards may jeopardize the viability of crops due to the scarcity of water under semiarid conditions. Erosion control, soil characteristics and vineyard production were evaluated using three different treatments: (i) traditional tillage as the control group, (ii) soil covered by Brachypodium distachyon and (iii) soil covered by Secale cereale. Such plant cover for soil protection among woody crops is not frequent under semiarid conditions. Sediment yield and runoff were collected from nine (3 treatments x 3 replications) plots of 2 m(2). Soil moisture, organic carbon content and aggregate stability were measured for one year. Simulated rainfall on plots was used as a source of complementary data. A reduction of 50% in the production of the vineyard was noticed in the Brachypodium-treatment, probably due to the lower degree of soil moisture at 35 cm depth. Nevertheless, there was efficient erosion control and the soil's organic carbon content increased. The Secale-treatment produced more runoff than tillage treatment. Traditional tilling produced the greatest yield, though it is considered unsustainable in the long term for hillside vineyards, as it lost 1059 g m(-2)y(-1), compared to 62 and 70 g m(-2)y(-1) lost in soil covered with Secale and Brachypodium, respectively. A high variability was found in the runoff coefficient, which was usually less than 1% under moderate rainfall, although it reached 45% under extreme events. The blind tasting of wine showed a slight preference for wine produced on vines subject to the Scenic treatment. Copyright (C) 2009 John Wiley & Sons, Ltd.