Spatio-Temporal Variation And Its Influencing Factors Of Selected Soil Properties Of The Red Soil In Low Hill Region

The contradiction between human being and land are daily intensified, which forces the people to destroy the forest to open up wasteland and satisfy the need of survival and development. Following the problem of land security, how to utilize the land safely and improve the soil fertility is becoming the key point to all of soil researchers. The red soils region in hill land is one kinds of natural environment, which is badly ecology stability, large undulation in biological tissue and productive force and responding sensitively to human being or instancy disaster. With the environment tends to disadvantage to utilize, its nutrient is easily losing, cutting down the fertility and reducing the productive of red soils.In this paper, the study area is Yujiang County which is typical of the South red region in Jiangxi Province. This study collected soil samples in 1983,1998 and 2001, and using geostatistics and GIS technology analyze the spato-temporal variation and its influencing factors of a large proportion of the scale of soil organic matter, total nitrogen and pH .This study provide scientific evidence for the study area and similar area to carry out scientific management of soil resources and take advantage of it reasonably. The results showed:From 1983 to 2001, the general trend in research areas is the soil organic matter and nitrogen increasing while soil pH decline.The overlay analysis of 1983 and 1998's soil spatial properties distribution was illustrated that the soil SOM, total nitrogen and pH in Yujiang country have rises and have falls. In this country's area, 51.38% regions' soil SOM content is raised, but 48.62% regions is declined. The total nitrogen contents is raised more than 15% in 46.35% regions and dropped more than 15% in 20.85% regions. That variation is all most the same with soil SOM. The rise regions are mainly in the north and south in our research area, the other are in the middle area. The soil pH is dropped in 79.55% regions, which 20.83% are dropped more than 0.30, 58.72% are between 0 and 0.30. Most of this country's soil pH is declined, but in the minima of the south,the middle east and the north area is raised.Through researching the different land utilization way, the different soil type and the different terrain the soil characteristic changes ,studies show that land utilization way, soil type and the terrain are the important factors which affect soil organic matter and the spato-temporal variation of total nitrogen. In the research area, the paddy field and the forest soil organic matter and total nitrogen content show the upward trend while the dry soil show the downward trend; In the aspect of soil organic matter content, the red soils organic matter content was significant upward trend, the paddy soils organic matter content decreased slightly, the Fluvo-aquic soils organic matter content was significant downward trend; In the aspect of total nitrogen content in soil, the red and paddy soils total nitrogen content is rising, and the Fluvo-aquic soils nitrogen content was the drop tendency; In hill land, the soil organic matter content and nitrogen content showed an upward trend while in the plains region showed a downward trend. This phenomenon is due to Yujiang County's majority arid land concentrated on the central plains areas. Since most regions of the county soil pH downward trend, the dry soilof the land utilization way descend to the soil pH of influence is biggest in the study area...