Effect of soil management strategies on the characteristics of the grapevine root system in irrigated vineyards under semi‐arid conditions

Background and Aims Several studies have shown that cover crops restrict the development of shallow grapevine roots and reduce vigour and yield in the vineyard. The objective of this study was to evaluate the long‐term effects, after 8 years, of four soil management practices on grapevine root development and on yield in irrigated vineyards under semi‐arid conditions. Methods and Results Four soil management treatments were established in the inter‐row: no‐tillage with herbicide application (herbicide treatment), tillage (tillage treatment), no‐tillage with self‐seeding annual grass cover crop [self‐seeding annual grass cover crop treatment (AGT)] and tillage with annual cereal seeding [annual cereal treatment (CT)]. The density of lignified grapevine roots was determined using the trench method during grapevine dormancy. The treatments CT and AGT increased grapevine root density as compared to bare soil treatments. In addition, annual cereal treatment and AGT reduced vigour and yield but only in extremely dry years. Conclusions Unlike previous studies on cover crops, our results show that annual cover crops enhance grapevine root growth both under the row and in the inter‐row as compared to bare soil management. The increased grapevine root growth was mainly due to the proliferation of fine roots (diameter less than or equal to 1 mm), while yield reduction was mainly due to fewer berries per bunch. Significance of the Study This study proves that coupling cover crop management with the grapevine growth cycle under irrigated semi‐arid conditions can improve vineyard sustainability with an average yield reduction of less than 15%. To achieve this goal, cover crop competition must be avoided during the stages of the grapevine most sensitive to water deficit or during periods of low water availability. These are mainly during fruitset and ripening.