Curva de liberação de fósforo de fosfato natural, termofosfato e superfosfato simples aplicado no solo sob cultivo de milho, feijao e soja

Abstract

Phosphorus is one of the most important nutrients for plants, especially in the main crops of southwestern Paraná, which include soybeans, corn and beans. It is one of the most exported macronutrients in grain form. In Brazil, due to the characteristics of our soils, where there is not much phosphorus available for plants, the use of phosphate fertilizers is extremely important for good crop development and productivity. The main sources used in the country are simple and triple superphosphate. However, there are other types of phosphorus sources that can be used, such as natural phosphate and thermophosphate. However, their low solubility makes them less used on Brazilian properties. The importance of experiments with this type of phosphate is to identify the availability of phosphorus that they provide to the soil, aiming at benefits for long- and medium-term management. Thus, the work consists of an analysis of the phosphorus release curve of different sources of phosphate fertilizers applied to soil under the cultivation of corn, beans and soybeans. The sources of P are natural phosphate, thermophosphate and simple superphosphate. An experimental field was set up at the Federal Technological University of Paraná in Dois Vizinhos campus. A dose of 100 kg ha-1 of P2O5 was applied by broadcasting during corn planting. Soil samples were collected at a depth of 0 to 5 cm on days 20, 40, 65, 90, 120, 160, 200 and 360 after application. The soil P levels were analyzed. The yield of all crops will be evaluated according to the treatment. The system had a greater accumulation of P-resin in the treatment with thermophosphate throughout the experiment, while natural phosphate and simple superphosphate did not differentiate between each other. In terms of productivity, thermophosphate showed the highest yield in soybeans, while simple superphosphate showed the highest yield in corn, while in beans there were no significant diferences between the sources.