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Research on the Characteristics of Soil Reservoir of Vegetation Restoration in Mountain Area of Southern Ningxia

Author: ZhangYang
Tutor: ZhaoShiWei
School: Graduate School,Chinese Academy of Sciences
Course: Soil
Keywords: Vegetation restoration Organic carbon Soil structure Soil Reservoir
CLC: S714
Type: Master's thesis
Year: 2009
Downloads: 62
Quote: 0
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Abstract

Thesis Ningnan mountainous farmland fallow, animal husbandry, and slopes short-term ban, artificial Caragana microphylla and grassland fencing four main vegetation restoration study, moisture characteristics of the soil profile, soil hydraulic properties, the dynamic changes of soil moisture after rain research, promote the improvement of the soil structure derived soil organic carbon accumulation, improved soil structure driven improve functional recovery of the soil reservoir conclusion. Specifically as follows: soil organic carbon content and gt; 0.25 mm water stable reunion body content of soil held water resistance and capillary pores degrees was highly significant positive related (P lt; 0.01), with the reunion of body sub-shaped dimension, soil bulk density and non- capillary porosity was highly significant negative correlation (P lt; 0.01). Are in line with the relationship between the soil moisture content and soil suction soil moisture characteristic curve: up to a very significant level. The parameters of a larger the value, the stronger the water-holding capacity. The four vegetation restoration practices gt; 0.25 mm water stable aggregates content, the parameters a, field capacity and soil saturated hydraulic conductivity (Ks) decreased with depth, the fractal dimension increases with depth. Farmland abandonment and artificial Caragana microphylla vegetation restoration practices are so gt; 0.25 mm water stable aggregate content increased to 290.42 g / kg and 392.92 g / kg, and a value increased to 15.27 and 15.50, the fractal dimension is reduced to 2.89 and 2.86 ,0-40 cm Ks to 0.33 mm / min and 0.88 mm / min. Animal husbandry, and slopes short-term ban three communities in the above-mentioned characteristics of the difference was not significant. Farmland fallow, the soil, animal husbandry and slopes short-term ban and artificial Caragana microphylla field capacity increased to 18% to 21%. Grassland enclosure vegetation recovery within 25 a time to extend with the fencing of water stable aggregates content, the a-value and field capacity were increased to 611.03 g / kg, 20.069 and 24.5%, the fractal dimension is reduced to 2.77, Ks increases to 1.00 mm / min, with fencing time continue to extend and stabilize. Grassland enclosure 17 a 0-5 cm above the subsoil Ks, restrictions on water infiltration disappeared. In comparison with the short-term farmland, animal husbandry, and slopes short-term ban artificial Caragana microphylla fencing grass more conducive to improve soil structure and moisture characteristics. Way of three grassland restoration, soil Ks with the organic carbon content increased exponentially growing trend, the higher the organic carbon content in the region of Ks to improve the stronger the effect. Grass the seal Yucai make a large number of organic carbon accumulation, and therefore more conducive to the improvement of soil Ks. Different vegetation restoration practices have little effect on the total storage capacity of the soil, but the impact of holding the allocation of storage capacity and gravity capacity and actual water storage capacity and storage efficiency. Recovery time with vegetation to extend the the gravity storage capacity suction holding capacity of transforming trend gravity storage capacity are much larger than the suction holding storage capacity. Farmland abandonment, animal husbandry, and slopes short-term ban and artificial Caragana microphylla holding capacity of 1900 t / ha ~ 2100 t / ha between grassland enclosure 25a constantly increased to 2534 t / ha, and then stabilized. Affect three grassland restoration in the way of actual soil water storage and water storage efficiency factor for soil organic carbon content and soil water holding capacity and non-capillary porosity. Affect of Artificial Caragana intermedia soil water storages and water storage efficiency factor of aggregates fractal dimension. Different vegetation restoration times after rainfall d, 3 d, 7 d soil moisture rate and storage capacity with vegetation recovery time increased. Four vegetation restoration practices in the artificial Caragana microphylla soil moisture active layer in the most shallow, only 30 cm, grassland enclosure 17 a soil moisture active layer that reach 60 cm. After rain water storage capacity of farmland abandonment and animal husbandry, and slopes ban short-term vegetation recovery the way governed topsoil Ks, grassland enclosure by soil organic carbon content and soil water holding capacity. 1 d ~ 7 d after rainfall, soil water consumption farmland abandonment by soil capillary porosity, animal husbandry, and slopes short-term ban by the soil bulk density, grassland enclosure is mainly influenced by the above-ground biomass. The use of soil structure modifier derived from the soil reservoir regulation, potato starch accumulation by recharge from rainfall, the water storage capacity of the soil reservoir recovery. Not applied the structure modifier soil, and water storage of each level were less than water absorbent applied. Soil conditioner regulation of farmland soil reservoir is feasible, further confirmed the role of soil structure and the soil reservoir.

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