Fertility Evaluation For Arable Land Under Different Ecological Conditions In Henan Provice

The waste of soil as well as food crisis is getting worse at present,soil fertility is the most important indicator of the arable food production.The scientific evaluation of soil fertility is needed for determining and improving the soil quality.Choosing Sanpi town, Wenshu town,Songji town as typical areas of paddy soil (Stagnic Anthrosol),cinnamon soil (Ustic Cambosols),Shangjiang black soil (Ustic Vertosols) of Henan province by collecting soil samples in these three towns using 3S tools,the spatial database was established. Some soil properties including total P, available P, available K, soil organic matter, pH value, total N, total K, texture, cation exchange capacity and bulk density are selected as indicators to evaluate the soil fertility using the method of AHP together with ENVI4.5 and ArcGIS 9.3 software, The research conclusions are as following:1 The average of the soil particle size can be described by the following order: cinnamon soil> Shangjiang black black soil> paddy soil. Using method of ordinary Kriging,the results of spatial interpolation of soil fertility evaluation factors show that the organic matter of sanpi town is poor,and the organic matter of Wenshu and Songji is better;the total P and available P are relatively poor and some more area in these two towns are needed to improve the level of the total P and available P;the pH value of the soil in Sanpi town is slightly acid, Songji town is calcaric while Wenshu town is in between;the level of total P of the soil in Wenshu and Songji town is poor;the level of cation exchange capacity of the soil in Sanpi town and Wenshu town is even worse than Songji town.2 The method of AHP with IFI is used to evaluate the soil fertility of the three towns,the results show that the area of the medium class soil of Sanpi town is the largest occupied accounting for 70.86%,the good 17.39% while the poor 11.75%;the medium class of Wenshu town accounts for 58%,the good 24%; the medium class of Wenshu town 56.86% while the good 24.7%;In overall, the soil fertility of Wenshu town is best,which is easier to improve.3 The level of the soil fertility can be classified by the mean of IFI along the following order:Wenshu town> Songji town> Sanpi town. Correlation analysis is conducted on IFI and crop yield including rice in Sanpi,corn in Wenshu and wheat in Songji that the fitting result of Wenshu town is poor while the results of Sanpi and Songji are better.It can be inferred that crop production is not only affected by soil fertility but also the soil environment,biological background, inputting management and so on.4 Comparing the arable soil conditions and evaluation results under different ecological conditions in Henan Province,the results show that the limiting factor of soil fertility of Songji town is P,while the area of poor class soil of total P of Sanpi town accounted 97.5%;the limiting factor of the farmland yield of Wenshu town is not the soil itself,but the water shortage or irrigation conditions;the limiting factor of Songji is the clay soil texture not good for farming practice.So the soil fertility is formed under different ecological conditions together with the soil characteristics that is the base for better soil and land use management.