Study On Soil Physical And Chemical Properties And Vegetation Growth Status At Different Geomorphological Positions Of The Hilly In Desert Steppe

Slope aspect and slope position are the main topographical factors, slope direction and position of slope of different affected the slope acceptance of solar radiation, precipitation is not the same, so that different slope direction, between different site of light, heat, water, soil and vegetation distribution are subject to certain influence. Based on this, this paper to desert grassland in hilly area as the research object to the modern vegetation ecology and restoration ecology theory as the instruction, through the combination of field investigation and indoor analysis means, different site parts of the desert grassland in hilly area of soil physical properties and vegetation growth characteristics were analyzed, a comprehensive analysis of the soil physical and chemical properties and vegetation growth status in hilly different positions and different slope to the variation, the conclusions are as follows:(1) Study on soil physical properties in different positions of hilly desert steppe showed:The soil bulk density in different slope with wavy changes, The soil bulk density due south, due west, southwest slope to a higher value, he soil bulk density is lower in the North and northwest, The soil bulk density in different positions of the size of the order:the top of slope> the middle slope>in the bottom of the slope, The results reveal consistent variance patterns according to the season and slope conditions (terrain types). More specifically, the soil temperature decreased from summer to autumn and from autumn to spring, with the largest variation occurring from May to June. Additionally, the soil temperatures were highest at hilltop positions, followed (in decreasing order) by south-facing slopes, shaded slopes, and basal slope (downhill) positions, which experienced the lowest soil temperatures. Statistical analysis showed that soil temperature differences between the hilltop and basal slope positions were significant. As for the soil moisture, the highest values were attained in September, and the second highest soil moisture values occurred in July and August, whereas the minimum values occurred in April. Variation in the soil moisture was greatest from June to July. The soil moisture content also differed according to terrain; the highest content was obtained in the basal slope positions, followed (in decreasing order) by leeward, windward slope positions, and hilltop positions, which experienced the lowest soil moisture. The soil moisture differences between the basal slope and hilltop positions were significant.(2) Study on hilly desert steppe in different positions of soil pH and soil organic matter showed that there is no significant difference in pH value, but the pH value is more than 7, and the soil is weakly alkaline-, The content of soil organic matter showed some variation characteristics with the slope direction, The content of soil organic matter is higher and higher to the North, The highest content of organic matter due north direction, And the content of soil organic matter in the other direction was significantly lower, south direction of the soil organic matter content was the lowest, only north direction of June 10th, soil organic matter content with different manifestations of the slope position out some changes in the law, the content of soil organic matter average order value: in the bottom of the slope> the middle slope> the top of slope, the bottom of the slope, the average of organic matter content higher than the average of organic matter content at the top of slope (P< 0.05).(3) Soil nitrogen showed some regularity with Soil slope variation, The soil nitrogen content is higher more to North slope, The average of soil nitrogen content the highest in the north, the content of soil nitrogen showed certain regularity according to the slope conditions, the content of soil nitrogen deficiency area mainly distributed the top of the hill, rich areas of low-lying bottom of the slope, the total nitrogen content of hilltop positions accounts for 87% of the basal slope, the available nitrogen content nitrogen content of hilltop positions accounts for 76% of the basal slope.(4) The content of soil phosphorus showed some characteristics with the changes of slope aspect. the content of total phosphorus did not change significantly, mainly in 0.350-0.356g/kg.The content of available phosphorus showed some characteristics with the changes of slope, The average content of soil available phosphorus is the largest of North Slope.the content of soil phosphorus showed certain regularity according to different geomorphological positions of Hilly, The content of available phosphorus were highest at basal slope (downhill) positions, followed (in decreasing order) by hilltop positions,the middle slope,which experienced the lowest The content of available phosphorus.(5) The content of soil potassium showed some variation with the changes of slope aspect. Soil total potassium content with change of the slope was not significant, difference is smaller, With the change of the slope, the content of available potassium in soil in north slope was the maximum, the second were northwest slope and West slope, the minimum were South slope and southwest slope.The soil potassium content also differed according to positions, the highest content was obtained in the basal slope positions, followed (in decreasing order) by the middle slope,and hilltop positions, which experienced the lowest soil potassium content. The total potassium content of hilltop positions accounts for 82.99%of the basal slope, with the change of slope positions, The content of available potassium in soil in the basal slope positions was the maximum, the middle slope and hilltop positions become smaller.(6)The results showed that the species composition and the important value of the plant communities in different landform parts in the hilly area of desert steppe:The species composition of plant community was significantly different with the change of slope direction and slope position, the more toward the north, the lower the slope position, the species richness of community was gradually increased;the structure of the Important value of slope to the north, krylovii, chinensis, cristatum although accounted for the dominant position, but the important value has been decreased, and composite important value increased.with important value change of slope position, Important values change with slope position is that the dominance degree of krylovii?chinensis? cristatum decreased with the decrease of the slope position.The degree dominance of frigidas ammannii and altaicus increases with the decrease of the slope position.krylovii are dominant at the bottom of the slope.cristatum are dominant in the hilltop positions.(7) The variation of vegetation coverage is different with the slope direction and slope position, Vegetation coverage and slope have a stronger correlation, the highest values were attained due north, followed (in decreasing order) by northwest, southwest, West, due south, which experienced the lowest values. Overall, the vegetation coverage in shaded slopes is higher than that in south-facing slopes, with the change of slope position, the change of the vegetation coverage is that in the basal slope positions was the maximum, the second were the middle slope, the minimum were hilltop positions. The lowest value were attained hilltop positions in the southwest slope; The variation of ground biomass is different with the slope direction and slope position, The slope direction from south to north, slope position from hilltop positions to the bottom of the slope, Above ground biomass increased gradually, the Above ground biomass differences between the basal slope and hilltop positions were significant. The change of plant community species composition with the slope direction is that slope direction is more North, Gramineae dominance decreased but still dominant functional groups, Compositae plant functional group, Convolvulaceae proportion increased, and occupy a certain position, The tendency of plant community species composition with the slope position is that the composition of the family is gradually rich with the decrease of the slope position, The hilltop positions is mainly Gramineae, Gramineae although dominant functional groups in the the middle slope and the bottom of the slope. the function superiority of Composite and the Convolvulaceae were improved.