BIOINPUTS: ANALYSIS OF POTASSIUM CONTENT AS AN ALTERNATIVE METHOD FOR BIOINPUTS PERFORMED IN ROOTS AND LEAVES OF SOYBEANS CULTIVATED WITH BIOTITE AND GRANITE REMINERALIZERS

Abstract

Soybean is among the world's main commodities, and Brazil depends heavily on chemical fertilizers: approximately 80% of synthetic nitrogen, phosphorus, and potassium fertilizers are imported, with a consumption growth trend of 6%, and, in some crops, fertilizers can account for up to 40% of total inputs. On the other hand, remineralizers (rock dust) provide efficiency to the planting process and rehabilitate the soil sustainably, without aggressive fertilizers. Given this, this study aimed to determine potassium content in root and leaf samples of soybean cultivated with remineralizers as alternative fertilizers. The analytical evaluation was performed by acid digestion with aqua regia, and potassium was quantified by atomic emission in a flame photometer, based on a calibration curve. Higher potassium content was observed in roots cultivated in Yellow Latosol compared to Red Latosol, both with granitic rock dust and biotite powder. For granitic rock powder in Red Latosol, leaf potassium content was higher than in Yellow Latosol, unlike biotite, which stood out in Yellow Latosol. The average content was 0.42% potassium in roots and 3.39% in leaves. Therefore, the use of biotite and granitic rock powder (remineralizers) as alternative fertilizers yields satisfactory results in supplying potassium to both roots and leaves.