Accumulation of biomass and nutrients in soybeans in an area of medium and high potential in the state of Mato Grosso, Brazil

Abstract

Aims Substantial variation exists in the patterns of uptake and remobilization of nutrients by modern varieties of soybeans. Furthermore, the fertilization programs in Brazil are often outdated. Thus, the objective of this work was to analyze these patterns in a soybean cultivar with indeterminate growth habit in two areas, one with moderate and the other with high productivity. Methods We analyzed the dry matter, macro and micronutrients in soybeans (Glycine max) divided into leaves, stems, pods and seeds, in six growth stages. The plants came from established farming areas with the same cultivation parameters and indeterminate growth habit. The data were used for descriptive analysis in function dry matter production, uptake of nutrients, harvest index, and nutrient uptake and remobilization rate. Results We found a greater uptake of nutrients in the older cultivars, mainly involving nitrogen, potassium and sulfur. And the nutrient removal, denoted by the harvest index, varied according to the location, with a trend of export of greater quantities of nitrogen and phosphorus. These increases were positively related with the dry matter content but not with the nutrient export. The rate of uptake and remobilization of nutrients changed with demand for nutrients throughout the crop cycle. Conclusions For sustainable production of soybeans in Brazil, we suggest revision of the fertilization manuals to increase the average yield. Agronomic practices also need to assure adequate availability of nutrients during the reproductive growth stage.