Application Research On Different Water Holding Agent Ratios In Base Materials For Rock Wall Vegetation Recovery

The experimental was in greenhouse and used common base materials and rate which being used in project practices. The Water Holding Agent was sated eight gradients, and the other materials were controlled in the same rate. Research and analysis the base materials with different gradients of Water Holding Agent and four different plants, the results showed that:(1)Adding a certain quantity of Water Holding Agent could improve the structure of base material and prolong the drought tolerance time of plants. Different Water Holding Agent contents had different influences of physical properties of base material. Water Holding Agent contents had a significant positive correlation with total porosity, and significant negative correlation with bulk density of the base materials.(2)Anti-scouring index, shear strength, germination rate and seedling height would be enhancing or higher with Water Holding Agent contents increasing when the contents less than 0.3%, at he summit when the content was 0.3% and be decreasing with contents increasing when the contents more than 0.3%.(3)Generally, the higher of the Water Holding Agent contents, the higher of the water contents, the lower of wither rate of the same plant in the same drought times. In germination stage, after forty-three, forty-four, thirty and forty drought days, the Trrifolium repens L., Amorpha fruticosa, Cosmos bipinnatus Cav and Lolium perenne would almost have no water to lose, the evaporation tended to zero, the wither rates were: 80%, 75%, 95% and 80%, and most of them had already dead.(5)Water losing of the base material was highest in 12:00-16:00, and second highest in 8:00-12:00 in one day. There was water losing but no condensation at night in greenhouse. 0-5cm base material layers had highest initial water content, but it also had the fastest water losing rate. After twenty drought days , the water content sequence of different layers was : 5-10cm>10-15cm>0-5cm.(6)The eight different gradients of Water Holding Agent could be defined four different groups: the first group include gradient 0%, 0.05%, 0.1% and 0.15%; the second group included gradient 0.2% and 0.3%; the third group was gradient 0.5%; the fourth was 1%. Using the Topsis comprehensive evaluation to analyze the optimum interval of Water Holding Agent contents was 0.15 %to 0.3%, and the inferior interval was 0.5% to 1% and gradient 0%.