Manejo da população de plantas e da adubação nitrogenada na produtividade e qualidade de sementes de trigo, produzidas em terras altas

Abstract

Wheat is the main winter cereal cultivated in Brazil, mainly in RS and PR, however, approximately half of domestic consumption still comes from imports. Among the constraints of this scenario, the low productivity and quality of seeds obtained in some regions stand out. In this sense, the adjustment of sowing density and nitrogen fertilization management are some potential alternatives overcome these obstacles. The objective of this study waws to evaluate the effect of sowing density and nitrogen fertilization management on the productivity and quality of wheat seeds, in the edaphoclimatic conditions of the southern region of Rio Grande do Sul, in upland conditions. The experiment was conducted between May and October 2021, at the Centro Agropecuário da Palma, in the municipality of Capão do Leão, Rio Grande do Sul. The experiment was arranged in randomized blocks, in a 2x2x6 factorial scheme, in which factor 1 consisted of fixed and variable nitrogen fertilization, factor 2 consisted of two row spacings, 0.17 and 0.25 cm, and factor 3 consisted of 6 sowing densities 17,25,35,43,60 and 69 plants per meter, each with 4 replications, totaling 96 experimental units. Some yield components were evaluated (number of tillers per plant and per meter, dry matter and grain productivity, hectoliter weight, and in relation to seed physiological quality, germination, accelerated aging and field emergence were evaluated. It was concluded that the 17 cm spacing between rows provided the highest grain and dry matter production, with no significant influence of sowing density on grain production, however the population of 39 plants per linear meter had the maximum productivity achieved, and the population of 17 plants per linear meter had the highest hectoliter weight. Nitrogen management did not significantly influence the parameters studied. The increase in sowing density levels reduced tillering, mainly due do tillering extinction at the highest density studied. The physiological quality of seeds was little influenced, however, it responded positively to the increase in plant population, with the maximum percentage of germination and vigor in accelerated aging in the population of 69 plants per linear meter, already in the first count that evaluates the initial start, predicting the vigor of the seeds the population of 46 plants per linear meter stood out, having the maximum germination. The spacing of 17 cm between rows showed greater emergence in the field. Both physiological quality tests showed results without much discrepancy.