Purpose To study the effect of initial water content on the disintegration of root-bearing soil in water-level-fluctuation zone of Three Parallel Rivers Region, providing a basis for soil erosion prevention and control and vegetation restoration in this area.
Methods The disintegration indexes of undisturbed root-bearing soil of five kinds of suitable plants such as Cynodon dactylon, Canna indica, Cyperus alternifolius, Arundo donax var. versicolor and Acorus calamus were measured by field disintegration test under different initial water content. The characteristics of roots were analyzed by root analyzer, and the correlation between the disintegration indexes and root characteristics was analyzed.
Results When the initial water content was 7.2%, 11.4%, 15.2% and 36.7% (saturated), the average disintegration amount of the root treatment was 77.0%, 92.4%, 112.1% and 362.8% of plain soil, respectively, and the disintegration rate was 71.4%, 106.6%, 127.5% and 400.0% of plain soil, respectively. In the unsaturated state, the roots with diameter≤1 mm had obvious anti-disintegration effect, while the roots with diameter>2 mm had the effect of promoting disintegration. In the saturated state, the relationship between root characteristics with diameter≤1 mm and disintegration amount and disintegration rate was not obvious, and the roots with diameter>1 mm had the effect of promoting disintegration. Among the five plant roots, C. dactylon had the strongest resistance to disintegration, and C. indica was the weakest.
Conclusion When the initial water content is low, the herb roots can inhibit the disintegration of soil; and when the initial water content is high, the roots will promote the disintegration of soil. Roots with diameter>2 mm have the effect of promoting disintegration. In the vegetation restoration of the water-level-fluctuation zone in the Three Parallel Rivers Region, fine root plants should be preferred under the premise of suitability.
DownLoad: