Chemical properties of Oxisol cultivated with corn in management systems of soil irrigated with swine production wastewater.

Waste generated from agribusiness, such as swine production, can be used in agricultural soil; however, certain technical criteria should be followed. The objective of this study was to evaluate the effects of different depths of irrigation with swine wastewater (SW), associated with the soil management system, on soil chemical attributes after two corn crop cycles. The experiments were conducted in the field, in an arrangement with two soil management systems (conventional tillage system - CTS and no-tillage system - NTS) and five depths of irrigation with SW (50%, 75%, 100%, 125% and 150% of evapotranspiration from the crop - ETc). Soil samples were collected at depths of 0-0.1 and 0.1-0.2 m to determine the pH, Ca, Mg, K, Na, Al, P, Fe, Cu and Zn at the end of each crop cycle. Soil nutrient contents increased with the application of SW irrigation in the two crop cycles and in the depths of 0-0.1 and 0.1-0.2 m, mainly with an increase of irrigation depths. No effect of the management systems was observed for the majority of the nutrients evaluated. The content of the heavy metals Cu and Zn remained below the critical limits established by the Brazilian Regulations.