| Cultivated land is decreasing year by year because of many reasons, which includes population growth, accelerated urbanization, industrialization expansion, agricultural structure adjustment and return grain to forest, etc. The quantity and quality of cultivated land is one of the division factors to nation security, and the decreasing quality and reducing quantity of cultivated land have a negative effect on the economic development and ecological environment. Soil nutrient is one of the most important factors to evaluate soil quality, which is one of the basic properties of soil resource. Soil nutrient is great significant to growth and reproduction of vegetation, and its form and richness decides the soil fertility. Our country is mountainous and the area of mountain accounts for 67% of the total area. Therefore, it’s of great significance to research the spatial distribution of soil nutrient in mountainous arable land to agricultural sustainable development. It is the basis of understanding the mountainous soil resources, improving agricultural production and sustainable development of agriculture to find out the content levels, distribution features and their relationships with environmental factors.This article takes mountainous county of Taihang mountain mountainous area in Baoding city as the study area, and collects 4749 soil samples of 0-20 cm topsoil to research the spatial variability and convenient for management of mountainous soil. In this study, GIS and geostatistical methods are combined to analyze the spatial distribution of soil organic matter(SOM) and available nutrients(N, P, K) by six Kriging interpolation methods, which include ordinary Kriging interpolation of soil nutrient content value,Kriging interpolation that combined geomorphic information, land type information, soil information, land type-soil information and geomorphology-soil information. On this basis,this article analyzes the environmental factors of mountainous soil nutrient(SOM,available N, P, K) and makes spatial distribution map of four soil nutrients, the main results are:1. The average values of SOM, hydrolyzable N, available P and available K are 17.22g/kg, 79.02 mg/kg, 23.21 mg/kg and 106.42 mg/kg, which shows that the contents of SOM and available P are lower level, while available P and available K are middle and higherlevel. The coefficient of variation of SOM, hydrolyzable N, available P and available K are33.97%, 36.95%, 92.36% and 46.34% respectively, which belongs to the medium variation.The data of four nutrients conform to the law of normal distribution, so geostatistics can be used to research the spatial variability of soil nutrients in mountainous soil of Baoding Coty.2. Using the geostatistical analysis module in Arc GIS10.0 and the six Kriging interpolations, the results show that: the best Kriging interpolation for SOM is KDLTR and next is KDMTR; the best Kriging interpolation for available N is KDMTR and next is KDLTR; the best Kriging interpolation for available P and available K is KDLTR and next is KTR.3. Comparing the figures and data can get the results that: Soil parent material is related to organic matter, hydrolyzable N and available K, and the correlation coefficients are 0.31, 0.25 and 0.28 respectively; Soil parent material is related to available P and the correlation coefficient is 0.19. Elevation is related to organic matter, hydrolyzable N and available P, and the correlation coefficients are 0.22, 0.39, and 0.31 respectively; effective accumulative temperature is related to organic matter and the correlation coefficient is 0.31;annual rainfall is related to organic matter and hydrolyzable N and the correlation coefficients are 0.55 and 0.36; distance from the village is related to organic matter,hydrolyzable N and available K, and the correlation coefficients are 0.32, 0.27 and 0.39.Soil parent material, elevation, annual rainfall and distance from the village all influence the spatial variability of mountainous soil nutrients, but the major factors still need future research. |
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