Calibração do aquacrop e avaliação de épocas de semeadura de cultivares de soja para os tabuleiros costeiros de Alagoas

Abstract

The cultivation of grains in the Coastal Tablelands of Alagoas expands in areas formerly cultivated with sugarcane. The cultivation of soy is recent in this region, therefore, information and technologies for its sustainable cultivation are scarce. In this way, the objective of this work was to define the best sowing times for soybean cultivars in the Coastal Tablelands of Alagoas. For this purpose, the AquaCrop model was used to simulate the growth and yield of the crop in twelve sowing periods, eight of which (April to July) included in the period recommended in the climatic zoning and two outside the recommended period. To perform the simulations, the model was calibrated with experimental data from two experiments conducted in the region. The meteorological data used in the simulations were from a climatological normal of forty-six years (1973-2018), obtained from an automatic weather station. The average annual precipitation (considering the 46 years of daily data) was 1.600 mm, in which the precipitations of the simulated sowing period (from March to August) represent 77% of the total (1.236 mm). The average fortnightly precipitation was 66 mm, close to the reference evapotranspiration values of 62 mm. The thermal variations between 20 and 30 °C during the simulated cycles were favorable for the growth and development of the soybean crop. The modeling efficiency, mean error, mean square root of the error and mean square root of the normalized error indicated that the model, duly parameterized, presents satisfactory performance. he sowing dates affected the productivity of the cultivars. The highest simulated yields are achieved when sowing occurs between April 16 and July 1. Early sowing before March and delayed sowing after July 16 should be avoided.

Keywords: agrometeorological modeling, soy culture, agricultural planning.