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The Effect of Management and Topography on Vegetation and Soil of Natural Grassland of Loess Plateau Slopeland in Gansu Province

Author: LiYanHong
Tutor: HouFuJiang
School: Lanzhou University
Course: Grassland
Keywords: Loess Plateau Management methods Terrain Natural grassland Vegetation Soil
CLC: S812
Type: Master's thesis
Year: 2007
Downloads: 131
Quote: 1
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Abstract


Loess Plateau is the the one of the the two major poverty-stricken District, of of the our country, is also the a the the the the the most serious of the soil erosion on the the in the world one of the regions. Mainly in the area of ??natural grassland grazing utilization remaining in the gully slope Strip, accounting for 27.3% -67.5% of the regional total land area of ??the Loess Plateau important agricultural production and ecological barrier. Trials conducted in 2005 and 2006 field test points of Pastoral Agriculture Science and Technology College of Lanzhou University, located in the the Longdong Loess Hilly Region, Gansu Province, Central County Sweetwater, research management (free grazing, fencing three years of grass closure sterility the the grass of 6 years), slope aspect (shady slope, sunny slope), slope (0 °, 15 °, 30 °, 45 °) on the to the extremely degraded grassland, all these indices including cover degrees, species composition, the aboveground of biological the amount of and the soil moisture the organic carbon of the, breathing, , the affect the of the total nitrogen, total phosphorus, quick-acting nitrogen and quick-acting quick-impact phosphorus of the, comparison the three on the the the the role of of the the an important indicator of of the Vegetation and soil. Main conclusions of are as follows that the: vegetation 1 increase in the Sui a hillclosing and afforestation useful lives, the The communities of the grasslands had cover degrees gradually rise in (P <0.05).. With the slope gradient increases, the the vegetation cover degrees gradually reduce the (P <0.05). Aspect cover. Under the a 2 of the a variety of management way, the a year biological number of species order of: freedom of grazing> seal sterility 3 years> seal sterility 6 years; Contrary to the law of the perennial species the number of changes in. Both Sui the slope and aspect change non-obvious rule. The total number of species with the management style and terrain change was not significant. Elevated by the 3 in grassland aboveground biomass of in Sui increase in enclosure years while the the the (P <0.05), and while the gradually reduce the the with the slope gradient increases. Aspect of biomass had no significant effect (P> 0.05). The leguminous the the the proportion of on Biological the amount of of Plants in turn for the that the: seal sterility the 6 years grassland> and seal sterility 3 years the grass> freedom of grazing the the grass. Soil 1 soil, soil water content as follows: fencing six years> enclosure 3> freely grazing land, but no significant rule changes with the slope and aspect. All the grass soil moisture are all in the July the highest. 2 In the from in May and July, when the the consistent of of slope and slope aspect, of grassland soil respiration strength in turn as follows: seal sterility 6 years> seal sterility 3 years> freedom of grazing land; and, with the increases of the with the slope gradient weakened (P <0.05). The of slope aspect on is respiration rate affect the the is not obvious. Respiratory maximum occurs in July. In November, the soil breathing with the slope gradient increasing the a parabola change, the the highest respiration rate of the 15 ° slope the grass, all sorts of ground management the way and slope aspect of non-remarkable the role of on the respiratory. 3 consistent slope and aspect, soil organic carbon density: fencing six years> 3 years> freely grazing land fencing. Shady slope the grass organic carbon density with slope increases and elevated, sunny no regular change. Aspect of soil organic carbon effect is not obvious. 4 the same the slope and aspect under the conditions of, the the Lawn soil nitrogen density, quick-impact nitrogen content of in turn for the: seal sterility 6 years> seal sterility 3 years> freedom of grazing land. The the the shady slope the grass nitrogen density and the the quick-impact nitrogen content with the slope gradient increase the to while the rise, the of slope aspect on the soil nitrogen the role of does not significantly. 5 slope and aspect of the same grass, soil total density, available phosphorus content with fencing of years to increase the overall upward trend (P <0.05), free grazing

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CLC: > Agricultural Sciences > Livestock, animal medicine,hunting,silkworm,bee > General Animal Science > Grassland Science,prairie school
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