Study On The Theory And Method Of Division Of The Basic Space Management Unit Of Soil And Water Conservation

Soil and water conservation is a professional field closely related to natural geographical environment,therefore relevant research and practice should be based on a certain spatial unit.At present,there is no unified basic spatial management unit at the micro-management level of soil and water conservation,and there is little research on relevant theories and methods.From the theoretical and methodological perspectives,this paper makes a systematic and in-depth study on the establishment of the basic spatial management unit of soil and water conservation in China,which is of great theoretical and practical significance in resolving the void of micro-scale management and deepening the theory of spatial management of soil and water conservation.It can provide guidelines for promoting the scientific and fine management of soil and water conservation work.Based both on the comprehensive analysis of domestic and foreign researches and water and soil conservation management needs,"water and soil conservation spot",the concept of basic management unit,is put forward in this paper,and the theoretical basis and basic principles of this concept are given from the perspective of basic theory.On this basis,we come up with the index system of patch unit division,and the researches are carried out on key extraction techniques on patch division index and the method of patch unit division.The patch unit updating and application mode are also discussed.Through theoretical analysis and case studies,it is shown that:(1)the basic management unit of soil and water conservation,i.e."water and soil conservation patches",is the basic spatial unit of soil erosion and its control,which is basically consistent in geographical and environmental conditions,relatively fixed in location and has clear boundaries,and it is the basic unit for carrying out management activities such as monitoring and evaluation of soil erosion,comprehensive control of soil and water loss,prevention and supervision.It is a unique spatial management unit in micro-management scale.(2)The basic theoretical basis behind the basic spatial management unit of soil and water conservation mainly includes the principles of soil erosion,soil and water conservation,geography,landscape ecology and cartography.Its characteristics include information comprehensiveness,boundary clarity,unit stability,patch homogeneity and so on.Its basic principles include the principle of hierarchical division,the principle of optimal scale,the principle of representation mode,and so on.(3)Based on the principle and characteristics of "water and soil conservation patches",the principle of choosing indicators is determined.According to the needs of soil and water conservation management,the indicators of patch classification include land use type,vegetation type,watershed dividing line,channel line,ditch edge line and soil type.The corresponding index extraction methods are put forward separately.For land use type and vegetation type research,the high-resolution remote sensing engineering pattern extraction method is proposed,the digital river network water system and watershed boundary extraction based on DEM is explored,and the object-oriented multi-scale segmentation and decision tree classification based on optimized geomorphological features and depth texture information are proposed.(4)Through the comparative study of three methods:spatial overlay method,semantic similarity analysis method and inheritance segmentation method,the semantic similarity analysis method is suitable for the division of "water conservation spots" in different regions;through practical analysis,the average area of "water conservation spots" in six main types of water erosion sample areas in China is between 13.52 hm2 and 49.85 hm2,with an average area of 25 hm2.(5)Aiming at the relative stability of "water retention spot",the object-oriented change detection updating mode method is explored.The accuracy evaluation results show that the mistake extraction rate is 50%,the Miss extraction rate is 5.88%,and the mistake extraction rate is higher,but the Miss extraction rate is lower.Manual removal of mistake extraction spot can effectively improve the updating efficiency of "water conservation spot".(6)The macro-micro spatial management framework system of soil and water conservation in China based on"soil and water conservation type area-small watershed unit-water conservation patch" and related application modes are put forward.The innovative points of this paper are as follows:through research and analysis,this paper clarifies the concept,characteristics and basic principles of the basic management unit of soil and water conservation;puts forward the principles,contents and extraction and analysis methods for the division of the basic management unit of soil and water conservation;studies three division methods of the basic management unit and their applicability,and puts forward its updating methods and a series of applications.The model has important guiding significance for the practice and application in the division of basic management units of soil and water conservation in China in the future.