Mining coproducts as alternative sources of nutrients for the cultivation of sugarcane (Saccharum officinarum)

The aim of this study was to evaluate the alterations in the chemical attributes of the soil and the nutritional attributes of leaves, as well as the productivity of sugarcane subjected to the use of mining coproducts from Irati and Corumbataí Formations. First, we performed the chemical and mineralogical characterizations of the inputs and the soil. The study was carried out in Paranavaí/PR – Brazil in Arenosol. The treatments were arranged within a split-plot system, designed in randomized blocks with four repetitions. The experimental plots were composed of 4 inputs that are sources of Ca, Mg and S (limestone, rhythmite, gypsum and fidagran) and, for the subplots, inputs that are sources of K (phonolite and clayey siltstone). Right after the application of the inputs, the sugarcane was planted. After 7 months of cultivation, we collected leaves for the determination of macronutrients and, after 14 months, the sugarcane was harvested. Afterwards, we collected the soil samples to determine the pH and the available ions P, K+, Ca2+, Mg2+, S–SO42-. According to the results, the rhythmite increased the soil pH, in general, by 27% in both subplots and contributed to an increase in Ca2+ (89%) and Mg2+ (307%) contents in the evaluated depths and S–SO42- (63%) at a depth of 20–40 cm. The treatments composed by phonolite allowed, on average, K+ 129% higher values than those found in clay siltstone. The inputs applied, in general, allowed greater accumulation of K, Mg and S by the plants. The results demonstrate that the mining coproducts from Irati and Corumbataí Formations can be used as alternative and clean sources of nutrients, increasing the contents of available ions in the soil and the accumulation of nutrients by the plants.