Study On Soil Nutrient Management Units In Hilly Region

In order to provide the information for the soil nutrient management, it's a great challenge for the agriculture researchers in China to manage soil nutrient suitability and the mode of site-specific nutrient management. In this research, Wutan county of Jiangjing and Renxian county of Liangping were selected as two experimental regions, studied soil nutrient spatial variability characteristics and analyzed the relativity between topographic features and nutrient distributing by using Geostatistical and GIS technology. With those understanding, made preliminary discussions on how to plot the management units of soil nutrient in hilly region. This will provide scientific bases for developing balance fertilizer application techniques, which are suitable to Chinese status of small scale farming management. The main results obtained are summarized as follows:1. Geographic and Geomorphologic analyze of study area. Through establishing DEM and three dimensional landform models of study areas, we discovered, two pilot areas have obvious difference in geographic and geomorphologic characteristic. In Wutan pilot area, the area is 100hm~2, elevations extents is 300~350 meters and gradients between 0°~55°. The smooth region (<3°) accounts for 47.04% of the total area, the gentle slope region (3°~10°) accounts for 37.86% of the total area, the slow center slope region (10°~15°) accounts for 10.18%, the steep slope region (>15°) accounts for 4.92% of the total area. The slope scope distribution of the entire region is quite dispersible, so the topography of the study region is quite uneven, and it is belong to the knoll low mountain and hill region landform type. The vegetable plot, the paddy field are the main land utilization type, all those occupy 80.12% of the study areas.In Renxian pilot area, the area is 100hm~2, elevations extents is 435~475 meters and gradients between 0°~59°. The smooth region (<3°) accounts for the total area 61.44%, the gentle slope region (3°~10°) accounts for the total area 25.35%, the slow center slope region (10°~15°) accounts for 5.80%, the steep slope region (>15°) accounts for the total area 7.41%. Comparing to Wutan, the Renxian pilot area majority of regions are smooth, only in the southeast area the topography has elevated more or little, and the relief amplitude obviously is smaller than Wutan obviously. Concurrently in the region there are the plain and the hill region two-landform types, most of which is the plain. The paddy field, the arid land are its main land utilization type, altogether accounts for the total area 74.56%.2. Preliminary evaluation of soil nutrient status. Available nutrient contents of surface soil samples from Wutan and Renxian experimental regions were determined by using the systematic approaches for soil nutrient evaluation. The soil nutrient statuses in Wutan and Renxian experimental...