SUPERFOSFATO TRIPLO NA EFICIÊNCIA DE USO DE FÓSFORO E DESENVOLVIMENTO RADICULAR EM GENÓTIPOS DE SOJA

Abstract

Soybean is currently the primary crop in the national agribusiness sector. Phosphorus is a limiting nutrient for achieving high yields, particularly in the soil conditions of the Brazilian Cerrado. Thus, this study aimed to analyze the effect of triple superphosphate doses on the yield of soybean genotypes under Cerrado conditions. The study was conducted in Pires do Rio, Goiás, Brazil, using a randomized block design in a 4×5 factorial scheme, corresponding to four soybean genotypes (AS3680, NA5909, NA7337, and TMG1180) and five phosphorus levels (0, 100, 200, 300, and 400 kg ha⁻¹ of P₂O₅) using Triple Superphosphate (41% P₂O₅ and 9% Ca), with four replications. Yield-related variables were evaluated at 146 days after sowing. Statistical analyses were performed using R Core Team (2019). The study revealed a significant interaction (p ≤ 0.05) between soybean genotypes and phosphate doses, in addition to significance (p ≤ 0.05) in the main effects. Regression models were fitted and estimated, with optimal points around 100 kg ha⁻¹ of P₂O₅ for various traits. Positive and negative correlations and their trends were assessed among the variables for each soybean genotype, along with factor interaction clustering. The traits contributing most to yield improvement were thousand-grain weight, plant stand, and pods per plant. Using triple superphosphate as a phosphorus source, the AS3680 genotype is recommended for cultivation, as it exhibited the highest yield (91.57 sc ha⁻¹) with a dose of 95.65 kg ha⁻¹ of P₂O₅, corresponding to a 21.57% increase in yield.