Spatial pattern matching analysis of grain production and rainfall in the Ziya River Basin

The exploratory spatial data analysis (ESDA) method, which includes global spatial autocorrelation and local spatial autocorrelation, is used to analyze the spatial pattern of the annual grain production and annual grain production increment in the Ziya River Basin from 2007 to 2017. Then, the spatial mismatch index is used to analyze the spatial mismatch relationship between the annual grain output and annual precipitation in the Ziya River Basin in 2015. The results showed that (1) the spatial pattern of the annual grain production in the Ziya River Basin is stable, with Low-Low clusters and High-High clusters concentrated on the left and right sides of the Ziya River Basin, respectively. The overall difference in the annual grain production of each district and county increased gradually from 2013 to 2017. (2) The local spatial correlation structure of the annual grain production of adjacent districts and counties in the Ziya River Basin had strong stability, and its space-time transition had a certain path dependence or spatial-locking characteristics. The reason why the High-High clusters are concentrated on the right side of the Ziya River is that there are large cultivated areas, such as the Shijin irrigation district, on the right side of the Ziya River Basin. (3) A spatial change rule "the proportion of grain production is low and the proportion of rainfall is high" changed to "the proportion of grain production and rainfall is balanced" and then to "the proportion of grain production is high and the proportion of rainfall is low" in the Ziya River Basin in 2015. The Shijin irrigation district is mainly located in the area where the spatial mismatch between the annual grain output and the average annual rainfall in the Ziya River Basin in 2015 is assessed as grade V, which indicates that the spatial mismatch between the annual grain output and the annual average rainfall is serious. In summary, grain production in the Shijin irrigation district has been increasing annually, while the supply of water for irrigation has not increased as much. There is a serious deficit between the irrigation water supply and the water demand for grain production in the Shijin irrigation district. Therefore, it is necessary to plan for the development and utilization of surface water and groundwater resources and to adjust the planting structure in the Shijin irrigation district for the purpose of saving water.