Study On The Soil Erodibility K-Value In The Typical Black Soil Zone Of Qiqihar City

The typical black soil zone of Qiqihar city, which mainly consists of black soil and chernozem, is the compartmentalized zone. The soil in this zone, however, is facing serious erosion problem and the ecosystem is deteriorating because of mankind long-term unreasonable development and utilization, which has restricted the sustaining development of the local economy and society. It is, therefore, imperative for us to strengthen the soil erosion research in order to decelerate the loss of the black soil. In order to preventing the soil erosion, it is necessary to conduct a quantitative study on the process of soil erosion and the appraisal of its environment effects, and soil prediction model is the most efficient means. The soil erodibility factor K, as the primary parameter of soil erosion prediction model, is the index to indicate the sensitivity degree of soil features to the erosion, and is the basis of soil erosion quantitative appraisal. The research and exact estimate is the foundation and premise of building soil erosion prediction model. This thesis, taking the soil erodibility factor K as the research object, studies soil erosion, and estimate the soil erodibility K value , by means of field observation and experiment analysis referring to American current USLE. It takes great efforts to apply the research results to the process of developing the soil erosion prediction model, and provide the basic data and the scientific foundation for the water and soil reservation in the typical black soil zone of Qiqihar City.In this research, the author takes the runoff erosion plots as the objects of which distributes in Ke Shan county, Bai Quan county, and Gan Nan county in the typical black soil zone of Qiqihar city. The methods of USLE, Nomogram Formula, Regression Analysis, Quantitative Statistic Model and GIS are utilized to study systemically the soil erodibility K value of Qiqihar city typical black soil zone. The specific contents of this research are the following:(1)Soil erodibility K value is estimated by USLE and the formulas. The measured and estimated erodibility K values of the runoff erosion areas in the three experiment bases are respectively that the clay in Ke Shan county (black soil subclasses) is 0.2205 and 0.1999; the brown clay in Bai Quan (black soil subclasses) is 0.3101and 0.2774; the Rust and oil black Loess in Gan Nan county (Meadow chernozem subclasses)is 0.3196 and 0.3061. The unit of K value is sht·ac·h/(100ac·ft·sht·in).(2)Repaired Nomogram Formula by Regression Analysis. The monistic linear regression model y=0.9823x+0.0269, is worked out from relative analysis and regression analysis on the basis of the measured value and the estimated value. The repaired Nomogram Formula is (3)K value of the unmeasured soil is estimated by the method of quantitative statistic model. The erodibility K value of all the research areas is estimated by applying the repaired Nomogram Formula. The erodibility K values of the relative soil subclasses, soil types, and the whole typical black soil zone in Qiqihar city are obtained in turn by weighted average area method. The erodibility K value of the black soil type is 0.2410, Chernozem types is 0.2405, typical black soil zone is 0.2408. The unit of K value is sht·ac·h/(100ac·ft·sht·in).(4)The production of K value distribution map by the method of GIS. The basemap of the soil is digitalized by ARCVIEW, and is put in the soil map on the basis of the K value data of the soil subcategory in the experiment areas, by which the K value spacial distribution map of the typical black soil zone in Qiqihar city is produced.