广东省大中型灌区用水量时空变化规律分析及影响因素识别OA

As a major agricultural water-using province,Guangdong Province relies heavily on improving irrigation efficiency to ensure food security.Based on the quarterly water consumption data of 453 large and medium-sized irrigation districts surveyed in the province in the past five years,this study reveals the temporal and spatial dynamic patterns of irrigation water consumption across the province by using statistical indicators,trend analysis and Getis-Ord Gi* hotspot analysis.The results show that:the province's large and medium-sized irrigation areas showed a significant decreasing trend in both irrigation water consumption and actual irrigated area between years,with an average annual decrease of 4.2%in irrigation water consumption(R²=0.886 5),but the decreasing trend in irrigation water consumption per unit area is not significant(R²=0.439 1),and the potential of water conservation remains to be explored.Affected by the water demand law of paddy rice,the third quarter each year is the peak water consumption period for large and medium-sized irrigation districts in the province,and the gross irrigation water consumption per unit area of large irrigation areas is slightly higher than that of medium-sized irrigation areas.The spatial differentiation of gross irrigation water consumption per unit area is significant,with the highest in the northern Guangdong,medium in the Pearl River Delta,fluctuations of high in winter and low in summer in the Leizhou Peninsula,and peak water use for late rice in the fourth quarter in the Chaoshan Plain.Irrigation efficiency is the dominant driving factor of irrigation water consumption per unit area in large and medium-sized irrigation areas of Guangdong Province.Particularly from the second to the fourth quarter,there is a significant negative correlation between irrigation efficiency and gross irrigation water consumption per unit area.Gross irrigation water consumption per unit area is negatively correlated with precipitation in all four quarters,but the correlation is significant only in the fourth quarter.Rice proportion is positively correlated with water consumption throughout the year(r=0.394～0.455 in the late rice season),though not significantly.The proportion of vegetable contributes positively to reducing water use through water-saving techniques,while the proportion of other crops has insignificant effects.The results of the study revealed the spatial and temporal dynamic distribution pattern and influencing factors of irrigation water consumption in large and medium-sized irrigation areas of Guangdong Province,which can provide a basis for decision-making on intensive utilization and sustainable development of regional agricultural water resources.