Environmental analysis of use of different sources of nutrients associated with soil tillage systems

Integrated analysis models can contribute to more efficient evaluation of the pollutant potential of sludge disposed in the environment. In order to study these aspects, an experiment was carried out for nine years on an Oxisol to evaluate five nutrient sources (three organic, one mineral, and a control) associated with five tillage systems in a subdivided block design, with three replications. The attributes used were available Cu and Zn, labile P compounds, diversity index of soil mesofauna, total N, and organic carbon content, as well as two questionnaires asking for technical opinions about the environmental impact of nutrient sources and soil tillage. In this evaluation a model was used which outputs, for each nutrient source within each soil tillage system, triangular figures and their areas, with a confidence interval of 90%. The nutrient sources were different regarding the environmental aspect, and the pig slurry was the worst source among them. Among the three indexes which took part in the environmental aspect, environmental risk index was the most critical considering the parameters and weights used.