Sensitivity analysis of the AquaCrop parameters for rainfed corn in the South of Brazil

Abstract: The objective of this work was to perform a sensitivity analysis of the main input parameters required for the AquaCrop water balance model, using biomass and grain yield data of a rainfed-simulated corn crop, obtained along the climate data series of 1987-2016 in the South of Brazil. The levels of soil-water stress and the depths of maximum effective rooting were the input parameters that most affected the biomass and grain yields simulated by the model, followed by the crop coefficient, water-use efficiency, soil water storage capacity, and contribution of groundwater to water availability in the root zone. The parameters crop cycle duration, plant density, pattern of soil-water extraction, and field surface practices showed little or no impact on the final results. AquaCrop is a robust water balance model, with small or moderate general sensitivity to variations of the main input parameter values, which makes it applicable to situations with field data limitations.摘要：本研究以巴西南部1987-2016年气候序列数据获取的雨养模拟玉米生物量与籽粒产量数据为基础，对AquaCrop（AquaCrop）水分平衡模型所需的主要输入参数开展敏感性分析。结果显示，土壤水分胁迫程度与最大有效根深是对该模型模拟的生物量与籽粒产量影响最大的输入参数，其次依次为作物系数、水分利用效率、土壤蓄水容量以及地下水对根区水分可获得性的贡献；而作物生育期时长、种植密度、土壤水分提取模式与田间地表管理措施对最终结果的影响极小甚至无显著影响。AquaCrop是一款性能稳健的水分平衡模型，对主要输入参数值的变化仅存在小幅或中等程度的整体敏感性，这使其可适用于田间数据有限的研究场景。