Spatial variability of rice irrigation quota and comprehensive irrigation quota in Yunnan Province

The rice irrigation quota and comprehensive irrigation quota are spatially continuous and interdependent. This paper, taking rice irrigation quota and comprehensive irrigation quota as examples from Yunnan Province, analyzes their distribution types and spatial variability structures. The two variables are close to lognormal and normal distribution, respectively, while their variograms are anisotropic and they mainly are influenced by the structure factors, such as the terrain landform, the meteorology and the soil. Their variograms can be described well by sphere model and linear model, respectively. Lastly, isograms of the two variables are obtained by Cokriging interpolatation. The rice irrigation quota is complex, changeable over the entire province and nonstationary varying with the latitude and longitude. However, the comprehensive irrigation quota varies regularly with the latitude and can be divided into four characteristic zones.