Spatial And Temporal Variability Of Soil Nutrients During Past30Years In Tong Chuan City

As a traditional mining city, Tongchuan City provided a lot of material for thedevelopment of related industries. At the same time, the rapid expansion of resourcedevelopment, resource depletion and abandoned underground mines, which affected localecological environment and land quality. Meanwhile, terrain and natural conditions of Tongchuan was varied, there was a big difference of fertilization among different farmland typesTherefore, the scientific method to evaluate changes in quality of the soil in the region wasessential, based on the data of the Cultivated Land Productivity Investigation and QualityEvaluation Project of Shaanxi Province (2006-2010) and the second quality of cultivated landfertility evaluation data of tongchuan city, we applied geostatistics in combination with GIS toanalyze Spatial and temporal variability of soil nutrients during past30years.The mainconclusions of this research are as follows:1. Based on the second quality of cultivated land fertility evaluation data of tong chuancity, the analysis shows that the overall of soil nutrients are moderately low. The content oforganic matter was lower than middle level; the content of nitrogen and four trace elementswere low; the content of Phosphorus was serious low, potassium and Cu content were rich.Distribution of eight kinds of soil nutrients was quite different. The higher content of organicmatter was in the middle of the research area, the lower was in the northwestern andsoutheastern area. In eastern and northern area, the content of phosphorus was high, while thelower part was southern and western area. The high content of AK was in middle and westernpart. The mainly level of AN content was moderate. From west to east, the content of soilavailable Fe was decreased, the mainly content of Mn and Zn were moderate and lack. Thehigh content of Cu was in the middle. Overall, soil nutrients in northern area were higher thanthe south; the west was higher than the east.2. According to the data of the Cultivated Land Productivity Investigation and QualityEvaluation Project of Shaanxi Province (2006-2010), the topsoil nutrient content was in amiddle level. The content of SOM, AN, AK were basically moderate, the lack of area werefew parts. The trace elements were in middle level, the content of AK was rich. From thespatial distribution pattern, the distribution of SOM, AP, Cu and Mn were similar, from north to south the content of these elements were increasing, while AN was opposite. The lowcontent of AP was in the middle of research area, the high part was in the north and south part.In this area, the content of Zn was moderate. Overall, the content of soil nutrient in northernpart was lower than that in south.3. During the past30years, the content of soil nutrient was an increasing trend, exceptAK and Cu, according to the variation coefficient of eight kinds of soil nutrients was mediumvariation, and had an increasing trend with time. Judging from distribution of changed contentgrade, in the middle of the research area, the content of SOM and major elements wereunchanged, the increased part was south. The content of trace elements between1980and2007were basically unchanged.4. The distribution of soil nutrients in today was different from that in the1980s, whichis mainly affected by human activities, during the past30years, with the development ofeconomic, improvement of agricultural infrastructure, increasing irrigated arable land areaand more fertilizer used, and many restrict agricultural production problems were solved insouth. These factors made soil nutrient content the constantly increasing. Geomorphologicand natural conditions were not conducive to agricultural production.