Simulação de sistemas agrícolas com uso do modelo Aquacrop parametrizado para culturas forrageiras em ambiente semiárido

Abstract

Knowledge of the best strategies for agricultural crops to meet the demand for food from livestock in a semiarid environment is essential, especially in periods of water scarcity. With this, the objective of the study was to calibrate and validate the AquaCrop model for simulating productive arrangements of forage crops, indicating parameters of practical applications and providing production perspectives for different locations in the Brazilian semiarid region. The model was calibrated and validated in agricultural areas located in Serra Talhada - PE, during the period from 2019 to 2020. 29 agricultural arrangements were simulated with forage crops such as forage cactus clones and sorghum varieties. Throughout the cycle, biometric and plant biomass data, information on soil conditions and management, variability of climate conditions, irrigation depths and levels of agricultural management were collected. The consistency of the parameterization of the AquaCrop model was performed through the analysis of statistical parameters (RMSE, NRMSE, R2, R, d and c). Consecutively, the parameterized model was expanded to estimate the biomass production and agricultural calendar for 14 locations representative of the semiarid region, considering their respective soil characteristics and historical meteorological variables (1961 - 2018). Thus, it was found that the AquaCrop model resulted in permissible errors in predicting the productivity of the evaluated agricultural systems, presenting a very good performance (c > 0.80) and a coefficient of determination (R2) greater than 0.80. The risk of losses increases when cultivation is carried out under rainfed conditions and decreases when irrigated. It was concluded that the AquaCrop model is an effective tool in predicting forage production and productive arrangements for the Brazilian semiarid region, with direct application in the indication of productive arrangements with better responses and aid in the elaboration of the agricultural calendar, planning and decision-making. However, additional investigations are needed to optimize the model applied to forage crops, integrating biotic factors in the simulations, in addition to different cropping arrangements.