Cotton Yield Response to Residual Fertilization and to Irrigation with Wastewater and Freshwater

Abstract

The by-product use in agriculture has become a very promising alternative, once that, when guaranteeing destination for high organic content residues produced in diverse human activities, includes environment and economic aspects. This is because by providing a high nutrient input to plants, allows the reduction of costs of chemical fertilization. Thus, the objective of this work was to evaluate the residual effect of chemical fertilization and organic fertilization on yield and its components of cotton in crop rotation with sesame, when irrigated with treated wastewater and freshwater. For this, cotton plants (Gossypium hirsutum L.) were cultivated in 20 L capacity pots which had been previously cultivate with sesame (Sesamum indicum L.). This plants had been submitted to the treatments that resulted of a factorial combination of five doses of castor meal in the soil (0, 2, 3, 4 and 5 ton ha-1), two qualities of irrigation water (freshwater and treated wastewater), and two additional treatments with chemical fertilization (NPK + freshwater and NPK + wastewater). The wastewater was treated in UASB reactor (Upflow Anaerobic Sludge Blanket) and the irrigation was carried through daily in accordance with culture water demand. The plants was cultivated until the end of the crop cycle and were determined the number of bolls for plant, mean weight of bolls and cotton yield for plant. Results showed that the residual effect of organic and chemical fertilization did not cause alteration the yield components and cotton yield. The irrigation with wastewater caused increase in cotton yield and its components in comparison to the plants irrigated with freshwater.