| Eastern hilly area of Sichuan is typical hilly area, the hilly region of the Mesozoic purple sandstone and mudstone, crunchy texture, highly vulnerable to erosion and weathering, resulting in serious soil erosion problem in the hilly area of cropland soil and water loss of the most prominent. How to solve the Soil Loss problem has become an important research topic. The terrace banks are a Slope Lands that control soil erosion, improve farmland ecological environment, improve the unit of land biological production capacity and economic capacity agroforestry system, the adequately use of land resources at the same time, improve the structure of the soil in sloping and nutrients, provide a good reference and a basis for the comprehensive utilization of mountain hilly area of land.In this study, taken the eastern hilly area of the terrace banks slope as the research object, Select four hemerocallis miner of biological ridge slope and biological ridge grid soil of different planting years were studied. For clearing root distribution characteristics of four different hemerocallis miner of planting years and their impacts on soil properties, a combination of research methods through field investigation and laboratory experiments, analysis of biological ridge slope on hemerocallis miner root distribution characteristics of root biomass, hemerocallis miner root diameter class distribution of root research; the study biological ridge slope on the structural characteristics of the soil, mainly from mechanical analysis of aggregate characteristics and its sub-dimension characteristics and soil corrosion resistance and other indicators; Finally, we discuss the biological ridge slope on soil nutrient changes, analysis of biological ridge slope on soil properties differences and the relationship between indicators and root. In this study, a comprehensive analysis of the nature of the plant roots and soil biological ridge slope, the results provide a theoretical basis for the grid biological ridge further promote, East Sichuan hilly area of terrace banks herbal selection and soil nutrient improvement provide a theoretical basis and practical application of the reference value. The main results are as follows:(1) With the increase of planting years, root length, root volume, root surface area and root volume indexes increase; and4-year-old Hemerocallis root vertical distribution are significantly higher than other planting years. Their values are respectively to185.3cm,17133items、237.5cm2、301.2cm3and158.9cm. The root system level distributions are different due to the restrictions of the grid size. Four different planting years Hemerocallis of the average root biomass of size sequence are as follows:4a>3a>2a>la. Different growth in different soil layers, there are also some differences of root biomass. Their variation equation fitting exponential function y=3.7722e1.2549×(R2=0.96) more suitable for this variation. Different growth years Huanghua root length, diameter class to L=1mm and L>4.5mm two diameter class-based, yellow roots fibrous roots and coarse roots. With the changes in the growth years, L>4.5mm root proportion also showed the same increasing trend.(2)The fractal dimension of soil mechanical composition in different development time was ranged from2.634to2.786,and shown as the sequence of4a>3a>2a> la>bare slop, and it was significantly related with the content of soil mechanical composition<0.05mm size class.The fractal dimension of soil micro-aggregates in different development period was ranged from2.486to2.602, and shown as the sequence of bare slop> la>2a>3a>4a, and it was significantly related with the content of soil mechanical composition<0.01mm size class. The influence of slope position on the fractal dimension of soil mechanical composition and micro-aggregates had obvious regularity, there was the regularity of up slope>middle slope>down slope in one-year development period to four-year development period on the fractal dimension of soil mechanical composition and the fractal of micro-aggregates showed up slope>middle slope>down slop, however, the bare slope respectively exhibited contrary tendency.(3) Biological ridge slope on soil organic matter with the variation of the slope position:top of the hill slope> the bottom of the slope. Growth years of organic matter consistent with the variation of the slope position, and the organic matter content of the bare slopes the same slope position than the control. With the implementation of life increases, grid soil organic matter content increased year by year, the performance of4a>3a>2A> la> CK. Different Planting Years in biological ridge soil pH value above7.40, the soil was alkaline. PH variation of different slope positions:top of the hill slope> its base. With the implementation of the increase of years, soil pH gradually becomes smaller.(4) Soil total nitrogen and total potassium content increased with soil depth variation:0-10cm soil layer is greater than10to20cm soil layer, the variation of the total phosphorus content. Total soil nitrogen content gradually increased with increasing growth years;4years old soil phosphorus content reaches the maximum,1,2,3years old soil total phosphorus little change; potassium content in the soil is much higher than nitrogen and phosphorus content in the soil. Soil nitrogen content with slope position variation:the top of the hill slope> bottom of the slope, from different ages of the same slope position of total soil nitrogen content differences significantly.1-year and2-year students yellow root soil of total phosphorus content changes with the slope bit changes from3years old and4years students yellow root soil of total phosphorus content in the law contrary,1-year and2-year raw yellow root soil of total phosphorus content changes with the slope bit variation:the top of the hill slope> the bottom of the slope. Different years the same slope position significantly different soil total nitrogen content. Slope position does not cause changes in the total potassium content, and no significant difference between slope positions. Vertical distribution of different growth years of soil available nitrogen content:the surface content of more than deep, from different ages of the same soil available nitrogen is insignificant. Vertical distribution of phosphorus content, by contrast, significant differences in different years of the same soil phosphorus content gradually increased with the growth years are greater than the control bare slope plots available phosphorus content. Different growth years of soil available nitrogen content the slope position changes in the law is basically the top of the hill> slope> significant differences in its base,1-year and2-year-old biological ridge soil available nitrogen and3,4years old. Different growth years of soil available phosphorus content with no significant variation of slope position, the volatility of the phosphorus content of the different years in the top of the hill and slope significantly different, and no significant difference in the bottom of the slope. Soil available potassium content volatility instability with the variation of soil depth and slope position, at different ages in the same soil available potassium significant difference.(5) The Hemerocallis root morphology not only affects the growth of plant itself, but also affects the soil fertilization. The Hemerocallis born in3,4years old root soil nutrient higher than1,2years old plants, and planting plant sample plot ratio control bare hillside high nutrient content.. Soil nutrient content had significant difference in different plant year of the same soil layer. Total N, available N and available P contents are effective and the Hemerocalli root indicators are significantly correlation. It is explain that the Hemerocalli roots through its soil and water conservation have the ability to change the soil nutrient. The herb has a good lower surface temperature, and maintains moisture. Plant through the leaves and stems of surface coverage, play a Xushuibaoshang role. Through the implementation of bio-ridge measures, biological ridge detention of farmland with slow and obvious effect of preventing sediment, gradually increasing the thickness of the soil, improve soil aggregate structure, improve soil fertility, prevent Soil Loss improved the ecological environment, to bring enormous ecological and economic benefits. |
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