Utilização do trigo sarraceno para mobilizar fósforo de fosfato de rocha para a produção de feijão comum

Abstract

Highly weathered soils from tropical regions have low availability of phosphorus (P) to plants, disfavoring agricultural production, making it necessary to use phosphate fertilizers, due to the high adsorption of P to soil constituents, but the continuous application of these can promote accumulation of P in forms not very available to plants, in addition to causing environmental impacts. Triple superphosphate (ST) is the main industrial source of P used in agriculture, due to the high concentration of this element and high solubility, but the use of P can be limited due to nutrient adsorption processes in the soil. Therefore, it became necessary to adopt forms that would increase the efficiency of the use of P in agricultural systems, such as the use of natural phosphate (FN) sources and green fertilization. In the case of natural phosphates, the supply of P is gradual throughout the development of the crop. Considering green fertilization, it is understood that buckwheat has a high capacity to solubilize phosphates, mobilizing poorly available forms of this element. Therefore, this crop was used to make P available to carioca beans, a characteristic culture because it has a low capacity to mobilize poorly available forms of P in the soil, and this element is essential in its development. The objective was to evaluate the effect of buckwheat biomass on the absorption of P from a FN by carioca beans. In the first trial, the soil incubation was carried out, an ortic Quartzarenic Neosol, with sources of ST and FN, in which the concentration of P and the biomass of buckwheat was evaluated, with or without the planting of buckwheat. After cultivation, its biomass was cut, incorporated into the soil and incubated until its decomposition, and was later used for the cultivation of the bean. In the second test, the biomass of the aerial part, root, leaf length and pod production were evaluated, comparing triple ST and FN, in the presence or absence of buckwheat biomass to the soil, and a source without the addition of P. The results indicated that the ST showed higher performance than the FN in all the variables analyzed, the incorporation of buckwheat biomass did not promote a significant increase in the availability of P for the carioca beans.