人民胜利渠灌区冬小麦灌溉需水量模拟与时空特征研究

Calculating the Spatiotemporal Changes in Requirement of Winter Wheat for Irrigation in the People's Victory Canal Irrigation District

【目的】研究人民胜利渠灌区冬小麦灌溉需水量的时空分布特征,明确冬小麦灌溉需水量对种植面积、降水量以及作物需水量的敏感性。【方法】采用基于土壤水分动态随机模型构建的灌溉需水量模型计算了灌区冬小麦灌溉需水量,利用面向对象分类方法获取人民胜利渠灌区冬小麦种植面积,并结合敏感性分析了冬小麦灌溉需水量的主要影响因素。【结果】2005—2015年人民胜利渠灌区冬小麦灌溉需水量整体随时间呈现波动变化趋势,多年平均灌溉需水量在175～238 mm之间;灌溉需水量分布变化比较稳定,总体呈现东部、西部高、中间低的特点。灌区冬小麦灌溉需水量对作物需水量最敏感,其次是日降水频率、冬小麦种植面积,日均降水量。【结论】冬小麦灌溉需水量时空差异较大,主要受作物需水量影响。

[Objective] The purpose of this paper was to calculate the spatiotemporal changes in the requirement of winter wheat for irrigation in the people＇s Victory Canal Irrigation District of Henan Province, as well as its consequent impact on cultivation areas of the wheat and sensitivity to precipitation and evapotranspiration. [Method] We first used the object-oriented change detection method to extract the cultivation area of the wheat in the irrigation district, and then, based on a soil moisture dynamic stochastic model, calculated the requirement of the wheat for irrigation. In the meantime, the main factors that affected the irrigation water requirement were also analyzed. [Result] The requirement of the wheat for irrigation in the district changed with time, with the average annual requirement for irrigation varying from 175 to 238 ram. In contrast, the spatial distribution of the de- mand for irrigation was stable, with the requirement in central region lower than that in the west and the east regions. The requirement of the wheat for irrigation was most sensitive to potential evapotranspiration, followed by daily precipitation frequency, cultivation areas and average daily precipitation. [Conclusion]The spatial and tem- poral variation of irrigation water requirement of winter wheat is relatively large, which is mainly affected by crop water requirement.