Study On Spatial Variability Of Soil Water Characteristics And Precision Irrigation In Western Semiarid Area Of Heilongjiang Province

Facing the increasing deficiency of water resources, agricultural water utilization of semiarid area in western Heilongjiang Province are becoming an outstanding problem. As the important commodity grain base, the effective approach to solve the serious seasonal drought problems is to use the efficient and water-saving irrigation measures, enhance the water use efficiency, and adopt different irrigation schemes based on various soil moisture contents. Thus, estimating the spatial distribution laws and actualizing precision irrigation schemes is the most efficient approach to save water and obtain high yield in the area.Chahayang Farm located in the semiarid area of western Heilongjiang Province is selected as the experiment base, and geostatistics and ArcGIS software are used to drawing the spatial distribution figures of the soil water characteristics in the study area. The spatial distribution figures can visually indicate the spatial distributing situations of the soil water characteristics, which provide the basic soil properties data for the actualization of precision irrigation.Numerical and visual methods to delineate irrigation management subareas are advanced in the paper for more rational design of precision irrigation scheme. The numerical method is to delineate management subareas with principal component analysis and MZA software, and the visual method is to directly delineate management subareas based on the spatial distribution figures and professional knowledge. Through calculating, two and four subareas of the study area are obtained by the numerical and visual methods respectively. The statistics analysis and single factor variance analysis indicate all the two methods are rational.Before the actualization of precision irrigation, layered sampling method is used to determine the rational sampling number of each subarea for the soil characteristics in the study area, and the rational sampling scheme is designed on the basis of a certain principle. The field monitoring system of soil moisture content can be arranged based on the sampling scheme of natural water content.During the course of precision irrigation actualization, the irrigation scheme can be confirmed by the comparison of natural water content and the irrigation index in the area. For the rational determination of the irrigation upper and lower limit, the water-saving irrigation experiments results of main crops in the area should be considered to confirm the irrigation water use.The whole process of precision irrigation is designed in the paper, including the spatial variability analysis, the delineation of irrigation management subareas, and the designs of rational sampling and irrigation schemes. The research results of the paper will provide guidance for the actualization of precision irrigation in the semiarid area of western Heilongjiang Province.