Aplicação de água residuária de suinocultura após dois anos sucessivos em sistema agroflorestal

Abstract

Swine breeding produces a large amount of waste, which are mostly managed in liquid form, what causes a demand for efficient and cost-effective alternative techniques in the treatment and disposal of the generated effluent. Considering the storage difficulty and the pollutant load of swine wastewater (SW), fertigation has become a viable and widely applied alternative. The experiment was carried out in the city of Uberlândia-MG and evaluated the chemical attributes of a Red Yellow Oxisoil, cultivated in agroforestry system, with Corymbia citriodora planted in simple line consortium with pasture formed with Urochoa decumbens, after two years of SW application. The experiment was set up in a randomized block design with 5 blocks and 5 treatments (0, 200, 400, 600 and 800 m³ ha-1 year), SW applications occurred in the years of 2015 and 2016. In conclusion, the application of swine wastewater did not change the exchangeable aluminum, aluminum saturation, exchangeable calcium, the relationship between calcium and CTC pH 7 contents and the organic carbon. The pH of the soil was practically unchanged. There was an increase of potassium, magnesium (in the superficial layer) and sodium, and the exchangeable sodium percentage occupied 15.32% of CTC. The increase of effective CTC, CTC pH 7, base saturation and base sum was mainly due to the higher levels of potassium, sodium and aluminum verified. The relationships between potassium and CTC pH 7 and magnesium and CTC pH 7 are below recommended. There was a raise of the heavy metals copper and zinc, being necessary to monitor them to avoid the contamination of the environment. Due to the sodium and metal contents it is not recommended to apply doses greater than 200 m3 ha-1.