Optimal soybean sowing window adjusted to climatic variability based on El Nino-Southern Oscillation using agrometeorological modeling

ABSTRACT Determining the optimal sowing window (OSW) based on climate variability associated with El Nino-Southern Oscillation (ENSO) can provide valuable information for agricultural planning in tropics. This study aimed to calibrate, evaluate and apply CROPGRO-Soybean model determining OSW across ENSO phases soybean-producing areas Pará State, northern Brazil. First, was calibrated evaluated using experimental data collected field, between 2006 2009. In this process, estimates showed a good agreement observed soybean phenology, growth yield, demonstrating potential simulate crop yield part of Amazon. After calibration, used seasonal mode 18 planting dates, over 39 years three locations. The simulated yields were divided into phases. set dates that high frequency (> 80 %) above 3,500 kg ha−1 integrated each location duration differed locations phases, varying more during La Nina than Nino events. However, regardless or phase, late suitable, because, besides favoring greater conditions development, yields, it also favors lower risk rainfall harvest period.