Spatial Variation And Influential Factors Of Soil Organic Carbon And Nitrogen Densities In Pengshan

Regional models of soil organic carbon (SOCD) and total nitrogen densities (STND) are important for monitoring the site-specific changes in soil carbon and nitrogen and for predicting large-scale patterns in C and N cycling. According to the1138samples in the Pengshan country, and adopt the geostatistics on the platform of ArcGIS9.3to study the spatial variation of SOCD and STND of topsoil (0to20cm). An integrated approach including traditional statistics analysis, analysis of variance, buffer analysis and regional statistics was applied to analyze the main natural and social economic factors affecting the distribution of SOCD and STND main factors, and on this basis by using grey correlation degree and principal component analysis method to research the influence degree of all kinds of natural and social economic factors of SOCD and STND. The main research results as follow:(1) SOCD and STND of0～20cm soil were all normal distribution, and the density values were3.24±1.06kg m-2å'Œ0.32±0.08kg m-2, respectively. On the whole, the distribution of organic carbon density were band or plaque shape, and with the most extensive of<3.50kg m-2level. Total nitrogen density become irregular plaques shape distribution, high value area (>0.41kg m-2) reduced to northwest, decreased first and then increased to east. The low value area (<0.25kg m-2) was mainly distributed in the northwestern and eastern round state zone.(2) According to the natural factors and social economic factors, and this research mainly study the effect of soil organic carbon and nitrogen distribution factors. The SOCD and STND from Minjiang river valley pleistocene were dramatically higher than from the sandstone and mudstone. SOCD and STND in different types of geomorphic, were the low hills (3.70kg m-20.34kg m-2)> moderate hills (3.25kg m-2,0.32kg m-2)> high hills (2.38kg m-2,0.27kg m-2). Soil organic carbon and total nitrogen density with the increasing slope presented first decreasing and then increasing and gradually decreasing trends, respectively. As the increasing buffer distance insects to Fu-Minjiang River and Nan-Minjiang River coast, SOCD and STND were rising, maximum reached3.53kg m-2and0.34kg m-2, respectively. SOCD and STND in the paddy field (4.68±1.21kg m-2,0.42±0.09kg m-2) were significantly higher than the vegetable, orchard and dry land. SOCD from3.58kg m-2down to3.33kg m-2, but the difference of STND was not significant in the2.00km insects away from the urban area. Within the1.00km insects outside Guanyin town, SOCD decreased with increasing distances, but increased in the1.20km insects to Qinglong. In the0.60km and4.00km distance insects, STND decreased to0.33kg m-2and0.31kg m-2with the increasing distances from two towns. SOCD decreased with increasing distance insects in the2.00km,4.00km and3.00km insects to the railway, main road and secondary roads. Within the2.00km and7.00km distance insects to railway and main road, STND decreased with increasing distances. But SOCD and STND in3.00km distance insects to highway all increased with increasing distances.(3) Basing on the analysis of natural and social economic factors, further to investigate the influence degree to soil organic carbon and nitrogen density by gray correlation degree and principal component analysis. The results showed that the river and geomorphy related mostly to SOCD, while parent material and road were the most associated influence to STND.