Aspectos ambientais e agronômicos da cultura do minimilho sob aplicação de água residuária de suinocultura tratada após lagoa de estabilização

Abstract

The application of swine wastewater in soils characterized as an efficient way to reduce fertilizer use and alternative destination for the waste. However, applications are not always made at the right time, in an amount that it considers its composition and also the needs of crops, which could result in contamination levels of soil, water and plant. The objective of this work was to evaluate the agronomic and environmental aspects of the use of swine wastewater and chemical fertilizer in the cultivation of corn (Zea mays L.) under conditions of drainage lysimeters for no tillage in the sixth cycle of cultivation. For this experiment was conducted in 24 drainage lysimeters, at Western Paraná State University´s Agricultural Engineering Experimental Nucleus, which soil was classified as Distroferic Red Latosoil, where they were applied prior to sowing four layers of swine wastewater (ARS), (0, 40, 80 and 120 kg ha-1 N) and two levels of mineral fertilizer (AD), (0 and 40 kg ha-1) as urea at sowing as well as coverage. At the time occurrence of precipitation the leachate were collected for analysis of pH and electrical conductivity (EC) and at the beginning, middle and end the cycle, samples for determination of pH, EC, Ca, Mg, P, K, Fe, Mn, Cu, Zn, N and N-NO3-. Also during the study, three collections were made at different times of soil before sowing and application of ARS, middle and end of the cycle for pH, cation exchange capacity (CEC), saturation of bases (V%), sum of bases (SB), organic matter, potential acidity (H + Aℓ+3), P , N, N-NO3-, K, Ca, Mg, Cu, Zn, Fe, Mn and Na. And yet the sodium adsorption ratio (SAR) were calculated for material and soil leachate, and exchangeable sodium percentage (ESP) to the ground. To determine the nutrient levels at the beginning of silking, leaf samples were collected from corn for later analysis of nutrients: total N, P, K, Ca, Mg, S, Mn, Cu, Zn, Fe and Na. The experimental design was completely randomized (CRD) in factorial 4 x 2 (four doses of ARS and two doses of AD) with three replications. Means were compared by Tukey test at 5% significance level, and growth data and leaf nutrient content submitted to regression analysis. The combined effect of ARS with AD, promote changes in soil properties: H + Aℓ +3, CEC, V%, P, K, Ca, Mg, NO3-, Cu, Zn and Na. In the material in the leachate pH, EC and Mg. On the levels of macro and micronutrients foliar these had values of P, Ca, Mg and S above the recommended N and K were below, whereas micronutrients are adequate. The higher doses favored higher results for plant height, leaf area, leaf area index, number of leaves per plant, absolute growth rate, on eating disorders and productivity data.