Comprehensive Evaluation Of Soil Qualityin A Mollisol Watershed China And Its Agricultural Managemental Zones

Land carries the function of human production,life and other aspects.It is the fundamental resource of human dependence.As the most direct carrier of the land,soil has a direct impact on human production and life.With the continuous progress of society,the continuous development of science and technology,and the continuous expansion of the city,the scale of land exploitation and utilization of mankind has reached an unprecedented level.However,in the process of the continuous development and utilization of land,some of the ecological environmental problems have been brought about,among which the problem of soil quality has been widely concerned.Environmental problems such as soil erosion,desertification and heavy metal pollution have seriously threatened the quality of soil and restricted the development of society to some extent.The accurate grasp of the problem of regional soil quality is of great significance and role in improving the productivity of cultivated land,improving the quality of the ecological environment and guiding the agricultural production area.Inthis paper,the typical northeast black soil area Haigouhe ditch River Basin as the research object,the design of the indoor sampling scheme,through field sampling and indoor test analysis,to obtain the soil surface soil element content in the study area,through the GIS spatial analysis,combined with environmental factors to comprehensive evaluation of soil quality in the research area,comprehensive land use information,and agricultural production zoning.The main conclusions are as follows:(1)1995-2015,the way of land use in the study area have small change,the main mode of transformation is the dry field turned into paddy field,the area of cultivated land showed a trend of decrease in general,but decrease rate is less,the waters area is slightly reduced,construction land and forest land area has a small increase.Overall,between 1995-2015,land use in the study area still is given priority to cultivated land.(2)Soil nutrient content in the study area at a higher level,the main nutrient elements SOM,TN,AN,TP,AP,TK and organic matter content were higher than the national background value,the spatial distribution of soil nutrients has significant correlation with the land use type,and soil fertility is good;The average content of three kinds of toxic heavy metals in soil including Hg,Pb and Cd is higher than the Songnen plains soil background value,higher than 23.16%,50%,204.04% that of soil background values respectively,the highest average contents of heavy metal is Cd,has more than the secondary standard of soil inorganic pollutants stipulated by the state.(3)The soil environmental quality assessment results: overall soil environmental quality in the study area is in good,mainly is medium and better level,the proportion were 42.16% and 25.36% respectively,mainly distribute the central plains region of study area,the poor environmental quality is 8.12%,mainly distribute rural residential areas near in block form;the good environmental quality is 11.56%,mainly distribute the eastern woodland in the study area.Soil fertility quality evaluation results: intermediate levels of soil fertility in the study area has the largest proportion of up to 51.24%,6.85% of high quality,mainly distribute in the paddy field in western area,9.68% of poor quality.(4)On the basis of the soil environmental quality and soil fertility quality,combined with the feature of topography and soil in the study area and irrigation capacity,make comprehensive evaluation of soil quality in the studied area,the soil quality in the study area is in good condition,which accounted for the largest medium soil quality,covers an area of 48.36 square kilometers,accounting for the proportion of the study area is 40.3%,mainly distributed in the central region,the area of best soil quality is 14.58 square kilometers,the proportion is 14.58%,mainly distributed western paddy field and eastern woodland of the study area;the soil of poor quality grade mainly distributed the junction of forests and plains,covers an area of 12.65 square kilometers.(5)Based on the results of comprehensive evaluation of soil quality and the current situation of land use in the small catchment of the Haigouhe watershed,this paper divides the agricultural production area into the optimum area of agricultural production,the reserve area,the general area and the forest ecological protection area,and rationally allocate the resources according to local conditions,and scientifically refer to the agricultural production.