关键词: 农业用水平价, 综合指标, 粮食安全, 水足迹, 空间自相关, 中国

Abstract:

The purpose of this study is to assess the agricultural water utilization in irrigated farmland of China based on water footprint of grain production evaluation. Having collected the data of 459 irrigation districts in 1998, 2005 and 2010, this paper calculates the grain production water footprint (GPWF) in irrigated farmland of China from a regional scale, and it then analyzes the relationship between grain production and agricultural water use by establishing an integrated water-grain rationality assessing indicator (I). The analyzed result shows that GPWF in Northeast and South China is high, while the low values are located around Huang- Huai-Hai Plain. GPWF in the regions of Hainan, Jilin, Liaoning and Heilongjiang exceed 2.400 m³/kg, while no more than 1.000 m³/kg in other six provinces, including Beijing, Shandong, Henan, Shanxi, Shaanxi and Hebei. The national value of GPWF during the study period is 1.336 m³/kg and the shares of blue and green water footprint are 64.1% and 35.9% respectively, and about 35.1% of the water footprint is not used for the crop evapotranspiration (ET). Same with the GPWF, the spatial difference of blue and green water footprint composition is big. Proportion of green water in GPWF as a whole (R_G) in Hubei is 58.5%, ranking the highest of all the 31 provinces of China. The RG in Zhejiang, Shandong, Henan and Sichuan is also above 50.0%. R_G in other 13 provinces is below the national value and no more than 20.0% in Jilin, Ningxia and Xinjiang. Spatial autocorrelation analysis results show that provinces with resembling water productivity values demonstrate significant aggregation. Local autocorrelation analysis reveals that more than 20 provinces show high- high positive autocorrelation (HH) or low- low positive autocorrelation (LL). General and regional spatial differentiation characteristics among the selected years are insignificant. The value of I is significantly different among provinces, which fluctuates between 0.114 and 0.850 and the variation coefficient is 0.55. Water use in regions located in the middle and lower reaches of the Yellow River is rational while the situation is the opposite for most areas of Northeast and Northwest China. The index I could explain the differences of relationships between grain production and water use in different regions. The 31 provinces are divided into four categories according to the parameters of agriculture water utilization and grain production capability, and the policies in resources management and food security safeguarding of all categories are discussed in this paper. Water footprint and water utilization in some regions could be improved significantly, especially the provinces in Northeast and Northwest China.

Key words: agricultural water utilization assessment, integrated indicator, food security, water footprint, spatial autocorrelation, China