Impact of Soil Nutrient Contents and Spatial Variability in Different Sampling Schemes under the Conservation Tillage

摘要

According to the 40×40m mesh, taking the 180 soil samples in both strains and ridges of the demonstration fields under the stalk mulching conservation tillage for 5 consecutive years in Gaojia country, which the area covers 15 hm~2 in Li Shu town, Jilin Province. The available N, available P, available K and other nutrition of soil in different sampling schemes have been tested. Based on the platform of GIS and the method of geostatistical analyst, the space distribution's characteristics of the three kinds of soil's nutrients have been researched, which demonstrate each variable corresponds normal distribution, the contents of available N and available K in different sampling schemes vary so much, but the content of available P has shown much more similarity than difference. Through the analysis of semivariogram, the soil nutrients in every different sampling schemes have revealed a moderate intensity autocorrelation and a relative strong spatial heterogeneity, which are affected by structural factors such as soil types, parent material, terrain, climate, hydrological conditions and so on, and they are also affected by random factors, for example, fertilization, cropping system, tillage operation and management. Analyzing the three nutrients in different sampling schemes, which are affected by random factors. Through applying the semivariogram and kriging to analyze the impacts factors of spatial variable in the soil, there are the differences between the two methods.