Variação de população de sementes de soja em função das zonas de manejo

Abstract

Abstract - The population variation of soybean seeds can be used according to the management zones (MZ) in the field. The MZ are regions within the same plot that have similar characteristics and productive potential. The objective of this study was to establish management zones in a given area, using the concept of the law of minimum as a determining fertility factor. Before installing the experiment in the field, a soil fertility mapping was performed using soil analysis in order to see the levels of the soil's nutritional elements, which were later used as variables in the experiment. The management zones were chosen according to the spatial variability of the nutrient potassium (K) and CEC (cation exchange capacity). Where the region of the area with lower fertility was sown more seeds, the region with higher fertility was sown fewer seeds, and the region with average fertility was sown the amount of seeds recommended by the company that markets the cultivar. The management zones were defined using the map algebra tool of the GIS program Qgis 3.28.2. Three management zones were established in an area of one hectare, namely: zone 1, the largest population 223,200 thousand seeds per ha-1; zone 2, average population 192,600 thousand seeds per ha-1, with the population of Management Zone 2 determined by the company that marketed the cultivar used in the experiment; and zone 3, the smallest population 169,200 thousand seeds per ha-1. This study found that when determining management zones in an area, variations in productivity occur in each management zone. The law of minimum is a factor to be considered when determining management zones. Hence the importance of this study, as it can help producers in making decisions for a better distribution of soybean seeds in the cerrado. In the area where the experiment was conducted, where soil fertility was higher and the population at sowing was lower, higher productivity was obtained. Where fertility was lower and the population at sowing was higher, lower productivity was obtained, when compared to the management zone with low population and higher in the zone with medium population. Key-words: Management Zones, Law of Minimum, Variable Seed Rate.