Labile and stable soil organic carbon and physical improvements using groundcovers in vineyards from central Spain.

Mediterranean vineyards are usually managed with continuous tillage to maintain bare soils leading to low organic matter stocks and soil degradation. Vineyards are part of the Mediterranean culture, their management can be sustainable. We propose the setup of two types of groundcovers with the aim to assess their potential influence to improve soil properties. A field trial was performed to compare the effects of a seeded (Brachypodium distachyon) and spontaneous groundcovers, on a set of soil parameters, in comparison with the traditional tillage in four vineyards located in the center of Spain. Three years after the groundcovers establishment soil organic carbon stocks increased up to 1.62 and 3.18Mgha for the seeded and the spontaneous groundcovers, respectively, compared to conventional tillage. Both labile and stable fractions improved their soil organic carbon content with the use of groundcovers, particularly the labile fraction. Moreover, soil structure and functional soil properties improved through better aggregate stability, pore connectivity and infiltration rates. The higher root biomass input of the spontaneous groundcovers derived in higher soil organic carbon increases and soil quality improvement. Consequently, under low rainfall conditions (<400mmperyear) spontaneous vegetation, properly managed according to site conditions, is an effective soil management strategy to revert soil degradation and increase soil quality in Mediterranean vineyards.