Adubação do solo e foliar a base de co-produtos de xisto em sistema de sucessão com hortaliças

Abstract

A major problem observed in growing vegetables, is the excessive use of highly concentrated soluble fertilizers, which has caused damage to soil biodiversity, to quality of the products and to the ecosystem. The objective of this study was to evaluate the effect of a fertilizer matrix based on shale by-products and of shale water, on production quality and productivity in a succession system of cultures consisting of strawberry, melon, lettuce and cover crops, in a soil with very high levels of macronutrients. A production system consisting of a succession of strawberry, melon, lettuce and cover plants, black oat intercropped with vetch, followed by crotalaria, was used. Sixteen treatments were used for strawberry and lettuce, which resulted from the combination of three factors: varieties, basic supplementary fertilization and leaf fertilization. For melon and cover plants four treatments were used resulting from the combination of two factors: varieties and complementary base fertilization. Foliar fertilizers based on shale water, combined with the nutrients Ca and B (strawberry) and Mg and Zn (lettuce) were used. The variables analyzed were production, functional compounds and total antioxidant activity, physicochemical, chemical analysis of the plant leaf, fruit and shoot and soil chemical analysis. Under the conditions of this study, conducted in a area with high level of initial fertility, the complementary base fertilization with MBR and foliar fertilization with shale water did not influence variables related to functional properties and chemical characteristics of strawberry and melon fruits, and of lettuce plants. The addition of the micronutrients Ca and B for the strawberries, and Zn and Mn for the lettuce in the foliar fertilization with shale water did not influence the production and quality of those crops, probably due to the high initial content of these nutrients in the soil. Of the nutrients analyzed, phosphorus was the only one who showed considerable reduction compared to the initial content, after the cultivation with only residual fertilizer, but remained in a high level in the soil.