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Studies on Characters and Effect of Soil and Water Conservation of Different Vegetation Communities in Loess Plateau

Author: ZhangHua
Tutor: ZhouJinXing
School: Chinese Academy of Forestry
Course: Ecology
Keywords: Loess Plateau Abandonment Species diversity Soil physical and chemical properties Runoff and sediment yield
CLC: S157
Type: Master's thesis
Year: 2009
Downloads: 151
Quote: 3
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Abstract

In this study, in order to master the different vegetation community characteristics fencing conditions change and plantation and natural ecological functional differences, \fencing under vegetation community structure, species diversity, soil physical and chemical properties of the soil erosion law system. The specific content and conclusions include the following aspects: (1) study found abandoned farmland vegetation communities: in the natural state abandoned for 30 years, according abandonment of years to sort results for abandonment 1 ~ 3a the Setaria lobular ghost of Bidens communities (B1), the abandoned farmland 5 ~ 11a Artemisia bushes stage (C2), abandoned 10 ~ 15a Artemisia gmelinii bungeana communities (D3) abandoned farmland 13 ~ 22a Elymus Uri Lespedeza Artemisia Communities (E4), abandoned farmland 24 ~ 30a the seabuckthorn community (F5). There were 43 kinds of herbs, shrubs four kinds, of which 55.81% of the species belong to the Gramineae, Leguminosae and Asteraceae, showed that the vegetation communities in the area obviously dominant families. Shannon-Wiener index and Pielou index with increasing abandoned years has increased in varying degrees, Simpson index was reduced. (2) in the sequence of the entire abandonment, soil bulk density range between 1.26 ~ 1.38 g/cm3, abandoned early 51.76% of the total soil porosity increases to 52.43% of the abandonment of the late, soil capillary porosity and soil moisture content is shown to be homogeneous by smaller impact of abandonment time. Vegetation communities of soil bulk density, total porosity, and water content increases with the increase of soil depth, soil capillary porosity with depth no obvious relationship. Small magnitude of changes in soil PH, the abandoned late F5 12.23g/kg organic matter content increases gradually abandoned early B1 7.52g/kg; gradual reduction of soil nitrogen and nitrogen content; increase in the phosphorus content of soil available soil phosphorus, potassium, and K content changes change is not obvious with the increase of abandoned years; under different vegetation communities in soil total N and available N table clustering effect. ∪? Erosion study found different vegetation communities through the field of artificial rainfall, the vegetation communities and sediment yield process line fluctuations. Abandoned early intensity of sediment yield and sediment yield, the abandoned late sediment yield strength and sediment yield was significantly reduced. Same rainfall intensity, the average runoff intensity size Sort: A0 (agricultural land) gt; D3 gt; E4 gt; C2 gt; B1 gt; F5, the ratio: 3.72:2.98:1.53:1.425:1.36:1.05; average production Sand intensity order of size: A0 gt; D3 gt; C2 gt; F5 gt; E4 gt; the the B1 ratio: 17.69:8.38:2.94:1.57:1.06:1. Respect, A0, B1, C2, D3, E4, F5 sediment reduction effect were 94.35%, 83.41%, 45.51%, 91.02%, 88.41%. Among them, the the seabuckthorn community better soil and water conservation function. Accumulated sediment yield and rainfall lasted into the linear relationship of y = ax b the rainfall intensity into y = aIb, power function relationship. (4) the ecological functions of the natural forest and plantation discovered natural forest shrub layer than artificial Lin developed, but the herbaceous layer of the plantation is superior to natural forests. The physical properties of the soil in the natural forests of aspen are better than Pinus tabulaeformis and Robinia pseudoacacia plantation. Davidiana under the soil organic matter and nitrogen content were greater than the other two species of the corresponding nutrient content, including 0-20cm soil organic matter content are Chinese pine plantation and locust plantation corresponding soil 1.17,4.56 times, the whole The nitrogen content of Chinese pine plantation and locust plantation corresponding soil 6.88,3.95 times. But the davidiana soil alkaline hydrolysis nitrogen (29.2mg/kg) low levels and low pH values. Stand understory runoff and sand strength differences are reflected in the cumulative production and the same rule of abortion sand, that locust forest gt; the oil pine gt; davidiana.

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CLC: > Agricultural Sciences > Agriculture as the foundation of science > Soil > Soil and Water Conservation
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