Desempenho do modelo AquaCrop/FAO® para cultivo do milho em Alagoas.

Abstract

The Maize (Zea mays L.) is an agricultural crop of great economic and social importance for Brazil. The objective of the present work was to evaluate the performance of the AquaCrop ® model based in the calibration of four planting seasons (E1, E2, E3 and E4) and to validate the same model for four crop cycles in three experimental stations Arapiraca (2008), Pão de Açúcar (2015) and Rio Largo (2015/2016) in the state of Alagoas for maize cultivation. And to identify the correlation between biomass data, grain yield, soil moisture and canopy cover observed and simulated. The input data for calibration of the model were provided by Sarmento (2015), and the elements that formed the database used for validation of the model were provided by Medeiros (2008), Anjos (2016), Cantarelli (2016) and Barbosa 2017). As well as, data collected from agrometeorological stations (maximum and minimum temperature, precipitation and components for quantification of reference evapotranspiration) located near the growing areas. The performance of the AquaCrop® model was evaluated through statistical comparisons using tests such as the concordance index, Pearson's correlation coefficient, confidence index, deviation percentage and mean root mean square root. During the calibration of the AquaCrop® model there was an overestimation of the data for the accumulation of biomass in the first, second and fourth planting seasons with 7.18; 14.58 and 0.56% for (E1, E2 and E4), respectively, and underestimate in grain yield at 5.98; 5.93 and 9.39% for E1, E2 and E4, respectively. During validation, the mean deviation for biomass accumulation was 7.31%, while grain yield was 3.3%. The soil cover data presented Willmont concordance index ranging from 0.94 to 0.99% for E3 and E1, respectively during the calibration, while in the validation ranged from 0.92 to 0.99 for Rio Largo, 2016; Arapiraca, 2008 and Rio Largo, 2015, respectively. As for soil water storage, Pearson's correlation coefficient ranged from 0.77 to 0.80 in (E1 and E4) and E2, respectively. The AquaCrop® model have an optimal adjustment to maize crop under climatic and soil conditions of Alagoas State.