Soil Nutrient Distribution Character Of The Main Grain Production Region In North China

Status, spatial distribution, spatial variability and its affecting factors of soil nutrient in Northeast plain and North China plain were studied using modern geo-statistics, geographic information technology and Soil Nutrient Systematic Approach(ASI). Different soil fertilizing manners were put forward. Main results were summarized as following:1 In Northeast Plain, variance coefficient of soil total nutrients was N>OM>P>K. All the Kurtosis of total nutrients belonged to high narrow peak. Total organic matter(OM) was normal distribution. Skew of total OM, N and P was positive, but total K was negative. Kurtosis and Skew of total N were higher than other nutrients(over 5%). The order of soil available nutrients was S>Fe>Mn>P>NH₄⁺-N>0M>B>Zn>Fe>Cu>Mg>K>pH. The kurtosis of pH was low broad peak, and kurtosis of other nutrients was high narrow peak. Date distribution of available Ca, Mg and Fe approached normal distribution. All available nutrients belonged to declining elements, which variance coefficient, kurtosis and skew were higher than soil total nutrients.2 Geo-statistics analysis on soil nutrient in Northeast Plain indicate that total OM, P, pH, available OM, P, K, Mg, S, B, Cu, Fe, Mn and Zn had semi-variance model, total N, K, NH₄⁺-N and available Ca had no semi-variance model, their semi-variance structure shows saddle or wave structure. Total OM, available OM and Fe had significant spatial self-correlation, other nutrients had medium spatial self-correlation. Spatial variability of total OM, P, available OM, B, Fe, Mn and Zn mainly resulted from structure variability. Spatial variability of pH, available P, K, Mg, S and Cu a half came from structure variability and another half came from random variability.3 Using traditional soil analysis method and ASI, Soil pH was mainly in 5.5～8.5 in Northeast plain. Total OM, N and K was medium, total K was rich. Deficient area of soil NH₄⁺-N, available P, K, S and Zn were 18.5%, 28.6%, 51.3%, 78.6% and 62%, respectively. Contents of available Ca, Mg, B, Fe and Mn were rich.4 In Northeast China plain, most of soil nutrients contents were decreased from northeast to southwest. Soil nutrient status of Sanjiang Plain was the best, Songnen Plain followed. Part of soil was deficient in available P, half of soil was deficient in available K and Zn, and most of soil was deficient in available S. Liaohe plain was the worst, which available NH₄⁺-N, P, K, S and Zn were deficient. Different fertilizer action should be taken according to those of three parts in Northeast Plain.5 In most areas of Northeast Plain, the distribution of total OM, N, P, NH₄⁺-N, available P, K, B, Cu, Mn, and Zn in top soil were higher than in bottom soil, but available Ca, Mg, S were adverse. However, total K content in top soil were lower than in bottom soil in Songnen and Liaohe Plain, which occupied about half areas of Northeast Plain. Soil total K, available Ca and Mg depleted seriously.6 According to soil nutrients status of Northeast Plain, soil fertilizing manner of Sanjiang plain was reducing N fertilizer application, controlling P fertilizer application and increasing K fertilizer application in part of area. Soil fertilizing manner of Songnen plain was stabilizing N fertilizer application, increasing P and K fertilizer application in part of area, and increasing the input of S fertilizer in most of field. Soil fertilizing manner of Songnen plain was increasing input of N, P, K, S and Zn fertilizer.7 In North China Plain, Variance coefficient of total nutrients below to 50% and N>OM>P>K. Kurtosis of total OM, N and P belong to high narrow peak, Kurtosis of total N higher than others obviously and total K was normal distribution. Kurtosis and Skew of total N higher than other total nutrients. The variance coefficient, kurtosis and skew of soil available nutrients were higher than soil total nutrients. The variance coefficient was S>Fe>P>Zn>Mn>K>B>OM>Cu>NH₄⁺-N>Mg>Ca>pH. Kurtosis of all the available nutrients belongs to high narrow peak. Soil NH₄⁺, kurtosis of available P and K affected strongly by fertilizer and other human factors, which had higher narrow peak than other nutrients. Skew order of available nutrients was NH₄⁺-N>K>Fe>Zn>Mn>pH>OM>Cu>P>S>B>Ca>Mg. Except pH, all the available nutrients belongs to declining elements.8 In North China Plain, geo-statistics analysis of soil nutrients showed that total OM, N, P, K, pH, NH₄⁺-N, available P, Ca, Mg, S, B, Cu, Fe, Mn and Zn had good semi-variance model, but available K had no semi-variance model, which semi-variance structure present wave character. Different soils in field of North China Plain had different nugget effect. Total P, pH, available Fe and Mn had strong spatial self-correlation. Total OM, K, available OM, Ca, Mg, S, B and Cu had medium spatial self-correlation. NH₄⁺-N and available Zn had faint spatial self-correlation. In soil nutrients, spatial variability of total P, pH, available OM, Ca, Mg and Mn mainly affected by structure factors. Spatial variability of Total OM, K, available P, B and Cu half came from structure variability, and another half came from random variability. Spatial variability of total N, NH4+-N and Zn mainly came from random variability.9 In North China plain, soil pH was mainly in 7.5～8.5. Above 80% area of soil total nutrients in medium range in top soil. Areas of soil total OM, N and P in low level increased with the soil depth. Area of soil available OM content below 1% was 97.3%. Deficient area of soil NH₄⁺-N, available K, S, Fe and Zn were 45.6%,35.2%,12.4%,11.4% and 69.7%, respectively. Contents of available P, Ca, Mg, B, Cu and Mn were rich. Areas of soil total OM, N and P in deficient level increased with the soil depth and other nutrients had little changes.10 Distribution regulation of soil nutrients in North China Plain was complex. Regulation in different layer of total OM, N, P, NH₄⁺-N, available OM, P, K, B, Cu, Fe, Mn and Zn was top layer>medium layer>bottom layer, but soil total K, pH, available Mg and S were adverse, and available Ca was top layer>medium layer>bottom layer occupation half percentage of plain. Soil total K, available Ca and Mg depleted seriously.11 Soil fertilizing manner of North China Plain was stabilizing input of N fertilizer application, decreasing or controlling P fertilizer application, and increasing K and S fertilizer application and supplement micro-elements appropriately...