The Characteristic Of Anti-erosion Characteristics On Slope Land Of Red Soil During The Growth Of Coin

On the basis of in-depth analysis of coin root growth characteristics, yellow brown soil on slope land was chosen as the research object. Soil chemical properties, anti-erodibility, anti-scourability and shear strength index during the four typical stages of coin were determined. In order to provide certain theoretical support and technical reference for scientific breeding of coin varieties and cultivation area in soil and water loss prevention of hilly yellow brown soil, the main conclusions are as follows:(1) Soaking experiments on soil aggregates was used for determining the temporal and space dynamic change rule of soil anti-erodibility index in corn-field. The results showed that soil anti-erodibility index displayed a decreasing trend with time increased; certain difference in soil anti-erodibility index appeared in the growth stages and in the vertical direction, for example, the decline of soil anti-erodibility index in seedling stage and grain stage was larger than that in flowering stage heading stage, and the decline of soil anti-erodibility index of 10-20 cm soil layer in grain stage was the smallest within soil profile depth. The growth of coin has a certain enhancing effect on the soil anti-erodibility index, which increases with the development of coin while increases first and then decreases in the vertical direction. For example, the enhancing effect of 10-20 cm is 72.11%, which is 1.54 times of 0-10 cm and 3.04 times of 20-30 cm. Soil anti-erodibility index correlated positively with soil organic matter and soil >2mmwater-stable aggregates(P<0.01), and was significantly correlated with <0.25 mm water-stable aggregates( P<0.05).(2)The enhancing effect of coin root on soil anti-scourability varied with growth stage and in soil profile direction. Taken no root soil(bare land) as control, the enhancing effect of the coin root on soil anti-scourability showed a decreasing trend after first increased within the development of growth stage. It reached the maximum at flowering stage for the three layers with the values of 122%, 192% and 167%. Soil bulk density, organic matter and >2mm water-stable aggregates can significantly improve soil ability against runoff destruction. Among the coin root parameters, root total surface area, total root length and < 1 mm root length correlated positively with soil anti-scourability(P< 0.01), and positively and negatively correlated with root volume separately(P< 0.05)(3)The tensile force increased in power function with increasing root diameter in the growth stages of coin. The tensile force decreased in the sequence of flowering stage(23.67N)>heading stage(22.95)> grain stage(12.45 N)> seedling stage(5.18 N). Tensile strength of single root and was negatively related with root diameter in the power function relationship. Lignin content, Holocellulose and the Lignin/Cellulose ratio all had the close relationship with the mechanical properties, for example, Lignin content, Holocellulose and the Lignin/Cellulose ratio correlated negatively with tensile force( P< 0.01).(4) With the developing of coin, the cohesive(C) of soil showed a trend of first increasing and then decreasing in the same soil layer, while a trend of continued increasing by soil layer in the same growth period. The change features of internal friction(φ) was similar to cohesive(C),which changed less obvious. Compared with the bare land, the growth of coin root can effectively increase the cohesive(C) and internal friction(φ) of soil, and this enhancement effect on soil cohesive was even more highlighted.From such an analysis, the added value of soil bulk density and root surface area density on the added value of soil shear strength was more significant than other factors such as root length density, average root diameter.