Potencial de rochas silicáticas no fornecimento de nutrientes para o solo e na nutrição mineral da soja

Abstract

The greenhouse study evaluate the effect of the application of potassium enriched silicate rocks (alkaline ultramarphic, pyroclastic breach and flogopitito) on the soil chemical properties, on the mineral nutrition and on soybean dry matter production. A Yellow Latossol witch 0.03 cmolc dm-3 soil was used in the study. The rocks were tested without lime and with lime, in this case lime was added to raise the percentage of base saturation (V-value) to 70%. The rocks materials and the lime were incorporated to each experimental unit, pots containing 3 kg of soil. The material was incubated at soil humidity around 80% of the field capacity, for 45 days. The silicate rocks were added at doses equivalent to 75, 150, 225 and 300 kg K2O ha-1. An additional pot containing soil and KCl, the reference K source, was also incubated. Soil samples were analyzed after the incubation and after the soybean sowing. Soybean was harvested 50 days after sowing, in the stage R2. The harvested material was dry in stove and saved for chemical analyses. The rock alkaline ultramafica without the application of calcareous was the treatment that promoted the highest soybean shoot biomass production. This result was similar to KCl with lime which also contributed to appropriate absorption of Ca, Mg, Fe and Mn. The pyroclastic breach and the flogopitito didn’t contribute to increment of the production of the aerial part of the soybean.