| Soil is the basis for human survival and development.With the rapid development of society and constantly increase in population,the absolute number of arable land and its per capita availability are declining.The conflict between people and land is increasingly tense and the most effective and feasible solution is to improve grain yield based on higher soil nutrients.Soil nutrients provide nutrition for the crop growth continuously.Soil enzyme activity is involved in the soil metabolism,and also plays an important role in the cycle of soil nutrients.It is significant to research the soil nutrient and enzyme activities for resolving the conflict between people and land.The purpose of this study is to analyze the soil nutrients and soil enzyme activities in Dazhai sponge fields.The study conducts a simple descriptive statistical analysis and a correlation analysis on various indicators of soil through using SPSS,and analyzes the spatial distribution and trends of soil nutrients and soil enzyme activities by using Arc GIS.Physical properties: The soil of the study area is sandy loam soil texture.Its bulk density and its porosity are suitable for the growth of crops.Chemical properties: The Ph of soil is ranging from 7.77 to 8.61,presenting alkaline.According to the second national soil nutrient classification standard,organic matter(OM)is moderate,total nitrogen(TN)is relatively abundant,available phosphorus(AP)and available potassium(AK)are relatively abundant,but available nitrogen(AN)is relatively poor.According to the second national soil trace element of available standard,available Cu and available Mn are basically in the right amount,while available Zn and available Fe are in the most poor,even very poor state.Biological properties: the variation coefficients of soil urease and catalase is moderate.Compared to the content of soil urease and catalase in forest and agricultural land in different areas,the content in the study area is low.The spatial distribution: The constant of OM is declined from the center to the edges,especially to the northeast and southwest.The spatial distribution of TN and that of AN are basically consistent with that of soil OM.AP and AK are descending from northwest to southeast.The effective Fe and the effective Cu are decreasing from the northwest to the southeast.The effective Mn is decreasing from the edges to the center of the study area.The spatial distribution characteristic of the effective Zn and that of the effective Mn is opposite.The catalase activity values are decreasing from northwest to southeast,and the urease activity values are high in the middle,and low in the edges.Correlation: The p H and effective Cu,effective Mn,effective Fe have a significant negative correlation.The p H and AK are significantly correlated.OM has a significant correlation with TN,AN and effective Zn,and has a significant negative correlation with catalase and effective Cu.There is a good correlation between soil nutrients and soil enzymes.Evaluation of soil nutrients: As for soil nutrients in the study area,47% of the sample point is at the level of an appropriate amount,43% at the rich level,5% at the very rich level,only 5% of the sampling points belonging to poor nutrient status;as the spatial distribution of Soil Fertility shows,the highest value is in the central part of the study area and the value is decreasing from center to surround. |
