Water retention characteristics and vegetation growth of biopolymer-treated silt soils

Abstract

Cement and other traditional materials are frequently used to improve the properties of soil in the Yellow River Basin, the ecological environment has become severely polluted. To promote the environmental protection strategy of sustainable development, environmentally friendly biopolymers were used to treat typical silt samples collected from the Yellow River Basin. The water retention characteristics and vegetation growth of the treated silt were evaluated, and the microscopic mechanism of the water retention characteristics was investigated. The results show that the water retention capacity of the treated silt increased upon increasing the ratio of xanthan gum, gellan gum, and guar gum, with gellan gum performing better than the other two gums. The biopolymers had no discernible effect on the vegetation germination, but effectively promoted vegetation growth with a significantly lower wilting rate than that of the untreated soil. The soil treated with xanthan gum had the highest germination rate and vegetation growth height, while soil treated with gellan gum had the lowest wilting rate. The superior performance of gellan gum and xanthan gum can be attributed to their hydrophilicity and adhesion. These gums directly interact with the surface of charged clay particles in the soil pore space to closely connect the particles, reduce water loss, and increase the water retention capacity. The better soil water retention capacity is associated with improved germination and vegetation growth.