Arranjo populacional e características do solo na produtividade e resposta espectral da cultura da soja

Abstract

Determining an appropriate seeding rate and establishing a soybean plant stand are essential factors for increasing crop productivity. The aim of this study was to evaluate the spectral response of soybean crops under varying soil conditions, as well as different populations and densities at various phenological stages. Five different soybean plant populations (162, 200, 250, 260, and 316 thousand plants per hectare) were assessed in a strip-plot statistical design. During the R5.1 phenological stage, a significant correlation was observed between soybean productivity and spectral response, emphasizing the importance of this analysis at this stage of the crop cycle. Seeding density influenced the plant cluster structure, resulting in a reduction in green mass in denser configurations due to intra-specific competition. The analyzed soybean cultivar maintained consistent productivity across different experimental approaches, suggesting economic limitations at higher seeding rates. Precise analysis of the Normalized Difference Vegetation Index (NDVI) and the crop's response to soil physicochemical properties, based on data collected in this study, will enable Brazilian cerrado producers to determine the optimal period for productivity forecasts, as well as better referencing the crop to be managed in specific soil characteristics. The GNDVI vegetation index at the phenological stage R5.3 showed a strong correlation with productivity at the end of the cultivation period. It was also evident, through the Duncan statistical methodology at 5%, that increasing the population did not elevate soybean crop productivity, highlighting economic limitations of this practice. The study will drive precision agriculture, providing greater accuracy in production and assessing the effects of variations in seeding rates.