Uso contínuo da água residuária de suinocultura em sistemas de produção de Urochloa

Abstract

The inadequate management of swine manure can potentially cause important environmental impacts, especially the pollution of water resources. In this sense, the use of these materials in the soil may represent advantages since it allows the reuse of an environmental liability as a chemical soil conditioner and/or source of nutrients for plants. However, the dynamics of this waste in the soil are complex, being affected by soil attributes, including biological activity, physical and chemical properties, climate, and the species grown in the destination area. Therefore, the experiment was conducted at Bonsucesso Farm, Uberlândia-MG, which was organized into three chapters where, in the first, it evaluated the effect of the application of swine wastewater (SW) on the chemical parameters of a dystrophic Red-Yellow Latosol with sandy texture in two systems: silvipastoral system and single pasture under simulation of grazing. The second evaluated the bromatological and nutritional characteristics of Urochloa decumbens under the application of SW in two silvipastoral systems and in single pasture under simulated grazing; and the third evaluated the effect of applying different doses of SW on soil acidity in the depth of 0 to 20 centimeters over a period of four years in a pasture of Urochloa decumbens. Each experiment was analyzed individually, and the statistical design used for each experiment was a randomized block design, a factorial 5x3x4 for soil attributes and 5x4 for plant attributes, with four repetitions for the single pasture and five repetitions for the silvipastoral systems. Five doses of swine wastewater were used: 0 (no application of SW), 200, 400, 600 and 800 m³ ha-1 year-1, and the chemical attributes of the soil were evaluated in the three depths 0.0-0.20; 0.20-0.40 and 0.40-0.60 m, and four consecutive years of SW application. The soil chemical attributes pH, Al3+, potential acidity (H+ + Al3+), available contents of macronutrients P, K, Ca, Mg and S, and micronutrients B, Cu, Fe, Zn and Mn, organic matter content, effective CEC (t), CEC pH 7.0 (T), base saturation (V %), aluminum saturation (m), and base sum (SB) were evaluated and U. decumbens: contents of macro and micronutrients in the dry mass of the aerial part and the percentages of FDN, FDA and PB after four years of application. Analyzing the results obtained, we recommend a dose of 400 m3 ha-1 year-1 for the single Urochloa decumbens pasture and the single-row and double-row silvipastoral systems.