Dwindling water resources and weather variability present two of the major limiting factors for irrigated cotton production in the Southern Great Plains (SGP) of the United States. Under these conditions, there is a dire need to understand the trends and fluctuations in cotton yields to help producers make better irrigation and crop management decisions. Crop models coupled with long-term weather data provide an opportunity for evaluating yield variabilities by simulating numerous potential scenarios. In this study, the AquaCrop model was calibrated and validated for cotton at two sites in the SGP. The validated model was then applied to investigate the effect of variable irrigation capacity (IC) on cotton yield during a 33-year period (1981–2013). The AquaCrop model performed with acceptable accuracy for simulating canopy cover, soil water content, evapotranspiration and yield indicating that it is a potential tool for evaluating variable cotton irrigation scenarios in the SGP. The response of cotton yield to IC was highly dependent on heat unit availability. Yields increased significantly with increase in water availability in years when total growing season heat units were above 1100 °C day. The yield response to irrigation diminished considerably as the magnitude of growing season heat units decreased. No significant increase in mean cotton yield was found at IC higher than 0.3 L s−1 ha−1.

中文翻译：

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AquaCrop 在美国南部大平原灌溉棉花上的验证和应用

水资源减少和天气变化是美国南部大平原 (SGP) 灌溉棉花生产的两个主要限制因素。在这种情况下，迫切需要了解棉花产量的趋势和波动，以帮助生产者做出更好的灌溉和作物管理决策。作物模型与长期天气数据相结合，为通过模拟众多潜在情景来评估产量变异性提供了机会。在这项研究中，AquaCrop 模型在 SGP 的两个地点针对棉花进行了校准和验证。然后应用经过验证的模型来研究 33 年期间（1981-2013 年）可变灌溉能力 (IC) 对棉花产量的影响。AquaCrop 模型以可接受的精度模拟冠层覆盖，土壤含水量、蒸散量和产量表明它是评估 SGP 中可变棉花灌溉方案的潜在工具。棉花产量对 IC 的响应高度依赖于热单位可用性。当总生长季节热量单位高于 1100 °C 天时，产量随着可用水量的增加而显着增加。随着生长季节热量单位的减少，对灌溉的产量响应显着降低。在高于 0.3 L s-1 ha-1 的 IC 下，未发现平均棉花产量显着增加。当总生长季节热量单位高于 1100 °C 天时，产量随着可用水量的增加而显着增加。随着生长季节热量单位的减少，对灌溉的产量响应显着降低。在高于 0.3 L s-1 ha-1 的 IC 下，未发现平均棉花产量显着增加。在总生长季热量单位高于 1100 °C 日的年份中，随着可用水量的增加，产量显着增加。随着生长季节热量单位的减少，对灌溉的产量响应显着降低。在高于 0.3 L s-1 ha-1 的 IC 下，未发现平均棉花产量显着增加。