SOIL AND WATER CONSERVATION IN CHINA No．5( 422) 2017

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The paper conducted statistics by taking Xigu District of Lanzhou City as studied area, area attribute information as unit and administrative village as a basic unit. It studied the principles and indexes (criterions) of soil and water conservation zoning of county-level urban type and determined the indexes used for soil and water conservation zoning, including landform feature, soil and water loss prevention and control system, land use and development orientation, mean annual precipitation, population density, forest and grassland coverage rate and percentage of soil and water loss area by using the combined method of qualitative and quantitative analysis. Through comparative analysis between the statistics of the area property and the function of soil and water conservation, it divided Xigu District into four six-level areas of southern margin ecological maintenance area, south soil and water conservation area, north soil conservation and sediment reduction area and middle living environment maintenance area, determined the orientation of layout of soil and water loss prevention and control system and land use of each function area and provided scientific basis for the layout of soil and water loss prevention and control system and soil and water conservation planning of Xigu District.

Key words: urban type; soil and water conservation zoning; Xigu District of Lanzhou City

Increasing the Accuracy of Chain Pin Method by Artificial Rainfall Simulation

LI Chunqian, LI Fengming, LIU Jinku, et al.

(Liaoning Provincial Key Laboratory of Soil Erosion and Soil and Water Conservation, Liaoning Institute of Soil and Water Conversation, Chaoyang, Liaoning 122000,China)(35)

It calculated and compared the amount of soil erosion by using artificial rainfall simulation and chain pin method under certain conditions. Then, it analyzed the correlation between the two and calibrated the chain pin method for increasing the accuracy of the method. The calculated results of the amount of soil erosion by using chain pin method was smaller than that of artificial rainfall simulation and the difference range of the two was 19%～30% under the conditions of rainfall intensity 40 mm/h, rainfall duration 30 min, slope 8°, vegetation coverage 0, initial soil bulk density 1.23 g/cm3and soil moisture content 14.79%. The related analysis results show that between the chain pin method and the artificial rainfall simulation is highly significant positive correlation (R=0.981 andP<0.05). Through establishing the regression model equation ofy=1.431x-27.237, it can correct the calculation results of the chain pin method under similar conditions and make the results are more close to the reality. In the future, further study on the relationship between the two under the different conditions will provide more accurate data support and decision-making guidance for soil and water loss monitoring of accumulated soil slopes in the fields.

artificial rainfall simulation; chain pin method; soil and water loss monitoring

Study on Computing Method of Rainfall Erosion Force and the Characteristics of Spatial Distribution of Liaoning Province

GONG Bing

(Liaoning Soil and Water Conservation Bureau, Shenyang, Liaoning 110003,China)(38)

The estimation results of rainfall erosion force will directly affect the accuracy of soil erosion prediction model. The paper calculated and compared the rainfall erosion force through classical algorithmEI30and daily rain model respectively and found out that the daily rain model was applicable for the calculation of rainfall erosion force of Liaoning Province. The obtained mean value of rainfall erosion force of Liaoning Province was 3 316.02 MJ·mm/(hm2·h·a), showing the trend of gradual reduction from east to west and from south to north in space by using the daily precipitation data of 39 weather stations of Liaoning Province and peripheral provinces in the period of 1961 to 2015. The minimum value of rainfall erosion force was Jianping County of Chaoyang City and the maximum value was Kuandian County of Dandong City.

Key words: rainfall erosion force; computing method; characteristics of spatial distribution; Liaoning Province

Study on Plant Community Diversity of Wetlands in Semi-Arid Area

HUANG Ruixing, YANG Binyuan, YU Xiaofang, et al.

(Jinhua Survey and Design Institute of Water Conservancy and Hydropower Co., LTD., Jinhua, Zhejiang 321017,China)(40)

In order to explore the variation of plant community diversity of wetlands in the semi-arid area, it selected Si’ertan wetland in Yanchi County of Ningxia as a study area, measured the plant community diversity by using Shannon-Wiener index, Simpson index, Pielou evenness index and Margalef species richness index, made cluster analysis by taking important value of vegetation as element and by using SPSS software and analyzed the vegetation types of the study area. The outcomes show that a) there are 41 plants species of 14 families in the study area, among them, the dominant families are Compositae, Gramineae, Leguminosae and Chenopodiaceae; b) the plant species are different in the different line transects of the study area. The plant species are the maximum in the south line transect and the minimum in the west line transect and; c) the plant frequency distribution of different line transects is different. There is the maximum plant species showed in 1 plot only of the south line transect and the maximum plant trees showed in more than 9 plots of the west line transect. Si’ertan wetland is divided into 4 communities ofKalidiumfoliatumcommunity,Leymussecalinus+Nitrariasibiricacommunity,Achnatherumsplendens+Artemisiahedinii+Phragmitesaustraliscommunity andArtemisiascoparia community. The diversity index of different line transects of the study area is different. The Shannon-Wiener index, Simpson index and Pielou evenness index of the north line transect are all the highest value, while the Shannon-Wiener index, Pielou evenness index and Margalef species richness index of the west line transect are all the lowest value.

Key words: wetland; plant community; species diversity; semi-arid area

Study on Soil and Water Conservation Zoning of County-Level Urban Type of Xigu District in Lanzhou City

HUI Xiaoya, ZHANG Fu, HU Yanting, et al.

(College of Forestry, Gansu Agricultural University, Lanzhou, Gansu 730070,China)(59)