Produtividade e qualidade de sementes de soja em diferentes zonas de manejo e densidade de plantio

Abstract

The fields of soybean (Glycine max L. Merrill) seed production are exposed of factors that influence their productivity attributes and final quality, and precision agriculture is a strong ally in decision making. The objective of the study was to evaluate the productivity and quality of soybeans seeds in areas with different productive potentials and plant populations, based on the generation of management zones. The experiment was conducted on the ElDorado farm, located in the city of Uberlândia - MG. Before defining the management zones (MZ), soil samples were collected (0-0.2 m) in a regular grid of 5 points/ha. The MZs considered the attributes altitude, soil apparent electrical conductivity (CEa), organic matter (MOS), clay and cation exchange capacity (T). For each of the two defined MZs, three soybean planting densities were established (230, 280 and 330 thousand plants ha-1) and three repetitions. The seeds were harvested in useful plots with an area equal to 8 m2, where the productivity was estimated at the final moisture of 13%. The weight of 1000 seeds (SMP) and the average diameter of the seeds were obtained, using sieves with apertures between 6.26 and 3.90 mm. The physiological quality of the seeds was determined by the germination test. It was possible to observe higher average productivity in the high yield potential MZ, especially for populations with 230 and 330 thousand plants ha-1. In the zone of low productive potential, the best productivity was observed for the population of 280 thousand plants ha-1. The highest SMP was obtained in the low yield potential MZ. The sieve test did not allow differentiation between both MZ, being obtained the highest retention of seeds in the sieve 14, with opening equal to 5.46 mm. Finally, the germination test showed the highest values, with an average of 78%, in the high potential MZ and a lower percentage of deformed seedlings. The population of 330 thousand plants ha-1 and the MZ with the high productive potential presented the best conditions for productivity and physical and physiological quality of soybean seeds.