Spatial Variability of Soil Nutrients under the Agroforestry Mode of Western Arid Areas——Take Zepu County in Xinjiang as example

[Objective]The purpose of this program was conducted to understand the spatial variability of soil nutrients under the Agroforestry mode.[Method]Traditional statistics combined with geostatistics was applied to analyze the spatial variation of soil nutrients by taking Zepu Country as an example.The spatial variability of the 5 nutrients;total available nitrogen,alkali - hydrolyzable nitrogen,organic matter,available phosphorus and available potassium under the topsoil(0 - 20 cm) was analyzed by using GIS combined with geo - statistics method on the Agroforestry mode,and then the results were compared with those of general detailed soil survey conducted in 1982 to study the soil nutrients change.[Result]The contents of the topsoil nutrients in our study area showed a normal distribution,the five kinds of soil nutrients varied differently,and the specific variability was displayed as follows:available phosphorusavailable potassiumalkali -hydrolyzable nitrogentotal nitrogenorganic Matter.The theory model of variation function curves of total nitrogen and organic matter was consistent with the exponential model,and the variation function curves of alkali - hydrolyzable nitrogen,available phosphorus and available potassium conformed to linear stepless model.The geographical distribution patterns of the five soil nutrients were revealed as high in the west and middle,low in the east,south and north.Compared with the results of 1982,the average soil nutrients of our study suggested that the contents of other four soil nutrients(except available potassium) all displayed the different increasing trends.And the available phosphorus increased most.[Conclusion]This research revealed that the contents of soil nutrients throughout the study area were modest or relatively low.Hence,we should increase the use of organic fertilizer,and pay more attention to the employment of nitrogen phosphorus fertilizer,and also emphasize expanding the input of potash fertilizer.Only in this way can we make sure the general improving of soil fertility,and the sustainable utilization and development of the cultivated land.