This technique entails adding herbaceous species to productive systems with the main goal of keeping the ground covered by vegetation in periods of the year in which no crops are being grown. The agroecological advantages of cover crops range from improvement of the soil structure, an increase in organic matter and nitrogen quantities and a reduction in pests and leaching. The species generally used belong to the leguminous, grass and cruciferae families. Cover crops that do not compete with the main orchard crop have to be used. Certain clover species are starting to be used in viticulture, even at under-vine level, in order to provide both nitrogen and, upon desiccation in May, to act as a layer of mulch. However, the cover crops require a certain amount of tillage of the ground, even though minimum, and therefore a certain organic carbon mineralisation. If well-chosen, they can help reduce leaching of the nutrients in periods in which the ground would otherwise be uncovered.
