Relationships between yield, enzymatic activity, and chemical properties across different soil layers and phenological stages of grapevines in southern Brazil

The activities of the enzymes (3-glucosidase (GLU) and arylsulfatase (ARYL) in annual crop soils can now be determined in several commercial laboratories in Brazil. The results are used to assess soil quality and recommend management practices. However, this technology is not yet available for vineyards. The objective of this study was to evaluate whether the activities of soil GLU and ARYL enzymes are related to grapevine yield and chemical properties in sandy vineyard soils, and to define the phenological stage of the crop and the soil sampling layer that best characterize these relationships. Soil and plant samples were collected in a commercial Vitis vinifera L. vineyard located in the extreme south of Brazil during the 2022/23. The soil was sampled in three layers (0-0.05, 0-0.10, and 0-0.20 m) and at four phenological stages (bud burst, full flowering, veraison, and post-harvest). The activities of the soil enzymes GLU and ARYL, the nutrient content of the soil and the leaf, the quality of the must, and the relative yield (RY) of the grapevine were evaluated. The RY was related to the activity of these enzymes. The best regression model adjustments were observed after harvest and in the 0-0.10 m layer. Enzyme activity was also significantly related to soil organic C and total N, as well as other soil properties, mainly P, K, Ca, Mg, Zn, and Mn. The activities of GLU and ARYL enzymes were related to grapevine yield and chemical properties in sandy vineyard soils and soil sampling in the 0-0.10 m layer after harvest is recommended.