Research on Precision Irrigation in Western Semiarid Area of Heilongjiang Province in China Based on GIS

Geostatistics and GIS were used to analyze the spatial variability of the soil water characteristics in western semiarid area of Heilongjiang province. Irrigation management zone was established based on spatial distribution of the soil water characteristics and actual condition of the study area. Sampling by layered sampling method and calculating of the rational sampling number by best distribution method for each management zone gave the results, saturated water content with the most rational sampling number 15, whereas natural water content with the least 3. The rational sampling number determined by layered sampling method was 85%~97% less than the measured sampling number. Measuring the natural water content for each management zone and comparing with the corresponding saturated water content, field moisture capacity and wilting point can determine whether management zone need to be irrigated. In addition, different irrigation lower bounds should be adopted under diverse irrigation requires.