Research On The Characteristics Of Soil Erosion In Different Forests Of The Small Watershed In Shangshe Of Dabie Mountains

In this paper, through the analysis of field soil of the Masson pine, fir and mulberry forests in the Dabie Mountain, physical and chemical properties of soil in the Dabie Mountains were systematically grasped, soil anti-erosion ability of Pinus massoniana forest and mulberry forest was evaluated respectively, rainfall was artificially simulated and effects of plant hedgerow and vegetation coverage on the erosion of soil slope of the Dabie mountains were studied. The main conclusion were as follows:(1) Soil organic C and N content varied significantlyThe organic C, N content of the field soil of pine forest and Chinese fir forest in the Dabie mountain decreased with the increase of soil depth, which kept uniform in the field soil of mulberry forests due to human cultivation and fertilization.The relationship of the organic C content of shallow soil was Pinus massoniana forest>fir forest>mulberry forest,field soil N content of mulberry forest was significantly higher than that of Pinus massoniana forest and Chinese fir forest.The content change of soil organic C has the same trend with that of soil aggregates which were bigger than 2 millimeters(2) Diversification of soil aggregates variationContent of soil aggregates over 2 mm of Pinus massoniana forest and Chinese fir forest in the Dabie mountain declined from the surface to the deep stratum,and the content of surface soil aggregates of of Pinus massoniana forest reached a maximum value of 71.80%, which proved that the erosion resistance of lower layers of the soil was weaker than that of upper layers.The compostion of 1.87% clay and 48.13% sand of watershed of Pinus massoniana forest was slightly higher than what of every soil layer of Pinus massoniana forest.Soil particle.Soil particles of fir forest watershed were washed down under the shallow layer of soil.(3) Root system dominated soil erosion resistanceIt is found that the soil anti erodibility of Masson pine is stronger than that of mulberry garden, and that in the range of 0—10 cm, Mulberry forest soil root <Masson pine roots in soil,the soil anti erodibility decreases with the increasing of soil depth; Roots are mainly in the 0—30cm level, and the root length decreases from the surface to the deep when the root diameter is less than1 mm, and the soil average pore size decreases with depth increasing, and the specific surface area increases with depth increasing;(4) Soil pore size was able to be used as reference to what attribute to the source of soil erosionMasson pines change the soil pore diameter significantly at 0—40 cm level, and the distribution of pore diameter presents the stratification while the differences of different soil layers in mulberry garden are less. the larger the soil porosity and soil pore size are, the strongerthe soil anti erodibility is, and the larger the soil particles the surface area is, the smaller the soil anti erodibility is; Through the spss analysis, it is concluded that soil anti erodibility and the roots quality are in significant correlation at the level 0.01 in mulberry garden. The average pore diameter and the root quality are in significant correlation at the level 0.05 in Masson pine forest.The flow from the soil of Pinus massoniana forest filled out in downfills and brought out soil particles, which caused large aperture distribution of runoff field soil of Pinus massoniana forest to coincide with what of 10-20 cm soil completely.People frequently turn the soil of the Mulberry forest, resulting in soil layers of similar nature which make soil erosion of earth’s surface serious during rainfall.(5) Sand and flow reduction effect of hedgerow was significantBy Simulating the rainfall of the Dabie Mountains rainfall, soil organic carbon loss increased with the increasing rainfall intensity, the effect of three factors on soil organic carbon loss was rainfall intensity>vegetation coverage > land slope. Under a land slope of 5 degree and a rainfall of 80mm/h,1.5m and 3m hedgerow covered soil will not form runoff in the initial stage of the rainfall.The flow reducing content of 3m hedgerow was 6.89%- 10.05%,and sediment reduction content of 3m hedgerow was 4.30%—9.38%.The flow reducing content of 1.5m hedgerow was 24.55%—70.67%,and sediment reduction content of 1.5m hedgerow was25.96%—58.63%. The flow reducing content of 1m hedgerow was 48.38%—78.67%.Due to the land cover of hedgerow and flow reduction of underground root system,runoff silt sand proportion of the land was bare>1m hedgerow >1.5m hedgerow >3m hedgerow,while clay ratio is opposite,showed a relation of 3m>1.5m hedgerow >1m plant hedgerow> bare land.