DEFINITION OF SEEDING TIMES FOR SOYBEAN IN ALAGOAS USING AQUACROP
agrometeorological modeling, soy culture, agricultural planning
Soybean cultivation has an important socioeconomic role for Brazilian agriculture due to its high productive potential in the different climatic regions of the country. Soybean is one of the crops that is expanding in the Coastal Plateaus of Alagoas. However, although soybeans are considered a crop with wide adaptation to the most diverse environments, information and technologies for soybean cultivation in this region are still scarce. Define the best sowing times for soybean cultivars in rainfed conditions for Alagoas using the AquaCrop model. Soybean productivity and growth simulations/evaluations were carried out for seven sowing date scenarios within the cultivation period recommended by the culture's zoning in the region. The seven scenarios tested sowing dates with an interval of fifteen days, starting from the first half of April to the second half of July. For this purpose, the AquaCrop agrometeorological model, version 6.1, developed by FAO, was used, calibrated with experimental data from soybean cultivars under conditions of supplementary irrigation and rainfed conditions. Experimental data were obtained from two experiments conducted in the study region. The model was parameterized and calibrated before being used in simulations of sowing dates. During the parameterization and calibration, the standard parameters of the model were changed, in order to obtain simulated results that correspond to the experimental data observed in the field. Soybean productivity was highly affected by sowing dates, the effects varied in all years. For most of the years studied, the highest simulated soybean yields were achieved when sowing occurred between seasons 4 and 8 (April 16 to July 1). Early sowing to March and late sowing after July 16 resulted in yield losses.