Grass sward cover improves soil organic carbon and nitrogen in a vineyard

ABSTRACT Historical depletion of agricultural soils must be remedied to maintain their long-term food production function, including soils in intensive vineyards traditionally kept without plant cover to limit resource competition. This paper reports on the impact of five contrasting soil management regimes on indicators of soil quality such as soil organic carbon, nitrogen and their indices. We exposed sandy loam Rendzic Leptosol under a vineyard in Nitra-Dražovce (Slovakia, central Europe) to the following five treatments for 14 years: no-till sward, no-till sward+NPK100, no-till sward+NPK125, plowed tillage and (5) plowed tillage+manure. We found that grass swards continuously increased the total soil organic carbon in the topsoil, but plowed tillage resulted in no change. The availability of potentially mineralizable nitrogen was also increased by grass cover; but was not modified by manure but by mineral fertilizer addition. We tested the usefulness of carbon and management indices as indicators of changing soil C and N status and found them no better than tracking total and labile forms of both elements. In conclusion, the recovery of degraded vineyard soils under no-till grass sward cover is detectable within 14 years and is not affected by fertilization or manure addition.