关键词: 水足迹, 灰水足迹, 水资源, 节水灌溉, 作物生产

Abstract: The demand of crop production to water resources is huge. In order to guide the strategies on water and nitrogen management study in sustainable agriculture, it is crucial to calculate the water footprint (WF) and analyze its characteristics. Taking Shaanxi province as the research area, WFs of three types crops including cereal, vegetable and fruit crops were calculated at the prefecture city level during 2011−2020 at the per unit area and total province level. The specific WFs and compositional structure, including green water footprint (GWF), blue water footprint (BWF) and grey water footprint (RWF) of major crop production at the prefecture city level and associated characteristics, were calculated and analyzed. Based on the calculation and analysis, suggestions on reducing WF and promoting for the sustainable agriculture were proposed. In the calculation, WF theory was used based on other data including meteorological data, statistical yearbook etc. Results showed that: (1) at the provincial level, the average WF per unit production area of major crops in Shaanxi province was ranked by: apples (10498.6m³ha⁻¹), open-field vegetable (10233.6m³ha⁻¹), soybean (5451.7m³ha⁻¹), summer maize (4771.9m³ha⁻¹) and winter wheat (3357.4m³ha⁻¹), the WF at per unit area for either apples or open-field vegetable were more than twice that of food crops, and non-natural precipitation water consumption (BWF and RWF) of open-field vegetable and apple production accounts for 75.7% and 55.3% in the total three fraction WFs, respectively. (2) The WF of crop production averaged in ten-years at the province level was ranked by apple (6.91 billion m³), open field vegetable (3.77 billion m³), winter wheat (3.37 billion m³), summer maize (2.68 billion m³) and soybeans (890 million m³) in order. The irrigation water consumed by open-field vegetables was higher than that for other crops, and the water consumption from either apples or open-field vegetables production due to nitrogen fertilizer application were higher than that from other crops. The water footprint of fruits and of vegetable crops, which consumed 47% of the total WF with only 31% of the total crop harvest area in the province. It is effective to optimize the water and fertilizer management in vegetable and fruit production processes to help release the potential of agricultural water conservation in Shaanxi province. (3) At the prefecture city level, the crop planting types in different regions in Shaanxi province were different. The WF for apple production was concentrated in the region of Yan'an, Xianyang and Weinan (77.0%), open-field vegetables was mainly planted in Guanzhong and Southern Shaanxi (90.4%), summer maize and winter wheat were mainly produced in Guanzhong (84.9% and 87.1%), and soybean planting was mainly concentrated in Northern and Southern of Shaanxi (81.1%). In order to reduce the WF of crop production aims to improve the efficiency of regional water resource use in different crop concentrated production areas, specific measures appropriated to local conditions and crop characteristics should be applied, such as techniques for rainwater collection and water-saving irrigation, high-efficiency water-saving irrigation technology and water-nitrogen coupled practices, so as to achieve the goal of sustainable agricultural development for ensuring saving water saving in crop production.

Key words: Water footprint, Grey water footprint, Water resources, Water-saving irrigation, Crop production