Efeito do parcelamento da adubação de n em cobertura na cultura do feijão

Abstract

Beans are a crop of great economic importance in Brazil, being one of the main sources of protein in the diet of the population. Additionally, it holds significant social relevance, especially for small farmers, often serving as their primary source of income. Brazil is one of the world’s largest producers and consumers of beans, with various varieties cultivated in different regions. Nitrogen fertilization is crucial for the growth and development of bean plants. The application of nitrogen topdressing, which occurs after planting, is particularly important as it helps provide a gradual supply of nitrogen to the plants during their growth cycle, promoting higher yield and quality of the grains. The aim of this experiment was to determine the best timing for the application of topdressing nitrogen to optimize its efficiency and maximize bean crop yields. To achieve this, three bean varieties were tested: BRS FC104, ANFC 5, and IAC 1849, with four applications of 60 kg/ha of nitrogen: Treatment 1 – control, no nitrogen application; Treatment 2 – application of the entire nitrogen dose at the second trifoliate stage; Treatment 3 – application of half the dose (30 kg/ha) at the second trifoliate stage and the other half at the fourth trifoliate stage; Treatment 4 – application of the entire nitrogen dose at the fourth trifoliate stage. The yield components varied significantly compared to the control and among the different bean varieties. Plant height, the number of pods, and the number of grains per plant were higher in treatments with the entire dose applied at the second trifoliate stage, half the dose at the second trifoliate stage and the other half at the fourth trifoliate stage, and the entire dose at the fourth trifoliate stage, compared to the control (no nitrogen application). The IAC 1849 cultivar had the highest number of pods, followed by BRS FC104, while ANFC 5 had the lowest. The treatment with split nitrogen application at the second and fourth trifoliate stages stood out with the highest number of grains per plant and yield, especially for the BRS FC104 cultivar. These results indicate that the nitrogen application treatments, particularly the split application at the second and fourth trifoliate stages, are superior to the control, with varying responses among cultivars. The BRS FC104 in the split nitrogen treatment proved to be the most productive combination.