Agronomic characteristics and macronutrient export of grain sorghum hybrids from different sowing dates

ABSTRACT Brazilian off-season cropping is increasing the production of cereals, particularly in the Brazilian savannah. Sorghum has been widely used for its grain production capacity and dry matter. Several hybrids are commercially available, each with its own peculiar nutrient absorption capacity. Thus, this study analyzed the agronomic characteristics and nutrient exportation in grain sorghum hybrids sown on different dates. The experiment was conducted at the Paulista Agency Regional Center of Agricultural Technology (APTA) in the city of Votuporanga, São Paulo. The experiment was conducted in a randomized block design with four replications and 4 hybrids. Sorghum hybrids (50A10, 50A50, BUSTER and 1G282) were the different treatments sown on four different dates, beginning with February 26, 2013, with the other dates 17, 30 and 41 days after the first sowing (DAFS). Each sowing date was considered an individual experiment and, subsequently, grouped for analysis to compare characteristics. Macronutrient content in the grain, one thousand grain weight, productivity and exportation of macronutrients (kg ha-1) by grains in the area were evaluated. The productivity of the sorghum hybrids varied depending on the sowing dates. The one thousand grain mass of the sorghum hybrids varied depending on the sowing dates. The average exportation of macronutrients by sorghum grains is as follows, in decreasing order: N> K> P>Ca> Mg> S. The mean values of macronutrient accumulation needed to produce one ton of sorghum grains are as follows: 20.05 kg N, 3.33 kg P, 3.70 kg K, 3.49 kg Ca, 1.77 kg Mg, and 0.72 kg S