| This study took the slope runoff field of Erdaoling small watershed in Fumeng County,Liaoning Province as the research object,and set up artificial runoff plots with different soil and water conservation measures.The combination of field manual monitoring and automatic instrument monitoring is used to monitor rainfall,surface runoff,and soil loss in the study area.The rainfall characteristics,the process of runoff and sediment production on the slope,and the benefits of different soil and water conservation measures to reduce runoff and sediment were analyzed,the result can provide scientific guidance for the formulation of soil and water conservation measures in low-mountain and hilly areas.The main conclusions of this thesis are:(1)By analyzing the rainfall characteristics of the study area from 2015 to 2021,there were96 erosive rainfalls,the total rainfall was 2327.4mm,and the total rainfall erosive force was11389.96MJ·mm/(hm~2·h).Among them,the rainfall frequency of light rain was 35,moderate rain was 31,heavy rain was 19,rainstorm was 8,torrential rain was 3,and heavy rainstorm was 0.The corresponding rainfalls are 177.4mm,527.4mm,653.6mm,686.6mm,382.4mm and 0 respectively,accounting for 7.6%,22.7%,28.1%,25.2%,16.4%and 0 of the total rainfall.(2)The average rainfall intensity from 2015 to 2021 is 1.02mm/h～3.59mm/h,and the maximum 30min rainfall intensity is 8.06mm/h～23.14mm/h.The largest difference between the maximum 30min rainfall intensity and the average rainfall intensity is in 2021,with the former being 6.9 times that of the latter;followed by 2017,which is 6.49 times.(3)The cubic function fitting results of rainfall and runoff in each runoff area are good,the coefficients of determination are all greater than 0.967,and there is a good correlation,and the correlation coefficients are all greater than 0.909.Among them,the best correlation between rainfall and runoff is ridge plant belt,and the best fitting effect is along ridge.The cubic function fitting results and correlation between rainfall and soil loss are also good,the coefficient of determination and correlation coefficient are greater than 0.914 and 0.834,respectively.The best correlation and fitting effect between rainfall and soil loss are contour ridge planting.(4)Through the correlation analysis between runoff and soil loss,it is found that the soil loss increases with the increase of runoff,and the best correlation and fitting effect between the two are in along ridge.The correlation coefficient and determination coefficient are 0.988 and 0.996,respectively.(5)The flow-reducing effects of various soil and water conservation measures are all positive.The order of flow-reducing effects of different soil and water conservation measures is:ecological restoration>fruit tree terraces>horizontal trough soil preparation>ridge plants belt>horizontal terraces>contoured furrows>along ridges.Negative sediment reduction effect appeared in along ridge in 2017 and 2021,and the sediment-reducing effect was the worst,while the sediment reduction effect values of other soil and water conservation measures were all positive.The order of sediment-reducing effect of different soil and water conservation measures is the same as the order of flow-reducing.(6)In the study area,vegetation coverage and management factors,factors of soil and water conservation engineering measures,and soil moisture content before rain are the main reasons for the different benefits of water and soil conservation measures in reducing flow and sediment in the study area.There are 14 figures,13 tables,and 115 references in this thesis. |
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