Spatial Heterogeneity Distribution Of Soil Available N, P And K And Its Influencing Factors

The soil is the most basic production material of agriculture and forestry, soil available N, P, K provide essential nutrients for plant growth, and it is an important factor to affect soil health and ecosystem productivity. Therefore, the study on the spatial variability of soil available N, P, K and its influencing factors is particularly important. Using the principle of mathematical statistics and geostatistics, using computer and GIS technology, in the central region of Heilongjiang Province as an example to study the surface soil available nitrogen, phosphorus and potassium of the semi variograms, constructed the theoretical model, systematic analysis of the three kinds of soil nutrients spatial variation rule, the main influence factors of the soil nutrient index were analyzed, the main research results are as follows:(1) The coefficient of variation range of the study area in the three soil nutrients between 39.77%-88.05%, belong to the moderate variability, variability in size order:K<N<P. Semivariance model analysis, soil available P and K in the study area nugget effect distribution range for 47.0%-49.4%, are moderate variation is caused by a common part of the structural factors and random spatial variability, land of this study use patterns and topographical factors on behalf of random factors and structural factors.(2) compared with the Kriging optimal in the generating method of soil available nitrogen, phosphorus and potassium space distribution diagram shows:available nitrogen content and distribution of average mainly distributed in low content of six, 96.81% of the whole research area accounted for, because of the nitrogen in the soil mainly exists in the form of organic forms, and the migration of nitrogen in the soil in high. The content of available phosphorus in the study area was in massive distribution, and the average content was mainly distributed in the level of two and three. Available potassium is rich in the western region from the north to the south to show a decreasing trend, the eastern region from the central to the surrounding decreasing trend.(3) the effect of soil type on available nitrogen was greatest, and the effect of available phosphorus was the least. In terrain factors, the elevation and the content of available nitrogen, available phosphorus showed significant positive correlation, slope and available nitrogen, available phosphorus were significantly correlated; slope to the influence of soil nutrient content has slope greater than that in the sunny slope of the trend. In the land use type, in addition to available potassium, other soil nutrient and land use patterns are smaller. There was a significant negative correlation between the distance from the road and available nitrogen and phosphorus, but there was no significant relationship between the available potassium and the available potassium.(4) soil fertility and its influence factors of the correlation analysis showed that soil types for the entire study area relative fertility content in positive effects; terrain factor most of the regression coefficient is positive, namely on the relative fertility for positive impact. The positive effect of land use on the relative soil fertility. Distance to road is negative effect on relative soil fertility.