| In this study, the feasibility of using wheat-bran as soilless lawn culture substrate, optimization of rotting wheat bran as substrate, and the effects of wheat bran-cultured perennial ryegrass lawn on soil and water conservation were analyzed. The rotting methods of wheat bran had three treatments, in which silt, sugar were used as rotting addition and the control had no addition. The lawn fertilization had four levels. Some physical and chemical properties of the substrate, as absorbable nutrient content of N, P and K, and amount of run-off and sediment of the lawn were measured. Using wheat-bran as soilless culture substrate to grow lawn or produce turf can be regard as a new method for slope protection, and we hope this method be applied widely for the control of soil erosion along roadway. The major findings are as follows:1. After composting with three different treatments, the total porosities of the matrix range from 65% to 78% and the pH values range from6.42 to 6.53, indicating that the main physical and chemical properties of wheat-bran matrix meet the basic requirements of good lawn matrix for soilless culture. But the water conversation ability of wheat-bran matrix was poor. We can solve this issue by controlling the environment or adding some other materials.2. In the course of culturing lawn of wheat-bran matrix, ryegrass can emergence five days later, and it can form lawn after 30 days. The physiological indexes of ryegrass after 30 days: seedling:emergence rate 3.1%-92.1%; leaf numbers 2-3; root number 3-5; root length 8-15.6 cm; root height 8.3-14.3 cm; root-shoot ratio 0.3-1.1. The result showed that the indexes in compost sludge treatment were better than in the sugar treatment and the control treatment And it significantly increased ryegrass growth rate. There was no significant difference between the sugar treatment and the control treatment. When the emergence rate was higher than 60%, the ryegrass after 30 days'seedling could be rolled in all treatments. At that time the lawn was in deep color and roots can combine the matrix tightly. 3. Treatments of 66.67 g/kg and 133.33 g/kg sluge compost could provide ryegrass better demand for nutrient, based on the analysis of N,P and K content in the matrix nutrients which was matured or into turf. The chlorophyll content and root activity value of ryegrass showed that treatment 25 g/m2 and treatment 50 g/m2 of manure increased ryegrass growth rate, while treatment 75 g/m2 inhibited the ryegrass growth. In conclusion, the combination of treatment 133.33 g/kg sluge compost and 50 g/m2 manure was the optimal treatment level.4. The cultured lawn at the optimized conditions was spread on the loess soil-underlaid erosion slots, and its effects on the conservation of soil and water were measured. The measuments had two treatments:one was slope degree with six levels (5°,10°,15°,20°, 25°and 30°), and the another was flux with three levels (100 L/h,150 L/h and 200 L/h). The results showed that the initial soil moisture, slope and flow had an influence on the slope contributing time. Either slope or flux increased, runoff would be brought forward. Effect of slope on the runoff can be enveloped at great flux. In the process of erosion, as the flow increased, the effect of slope changes on the runoff would decreased. After erosion, as the slope increased, the stopped-flow time decreased and the soil water dynamic retention decreased. The stopped-flow time was more longer and the protection properties were more better when the slope was at 5°and 10°. The sediment produced in the process of erosion increased as the slope and flow increased. The maximum sediment was different at different slope. More sediments occurred in the case when the slope degree were 10°and 20°at the flux of 200 L/h, and when the slope degree were 15°,25°and 30°at the flux of 150 L/h. There was no sediments occurring when the slope degree was 5°. In conclusion, lawn cultured in the substrate of wheat-bran have considerable anti-erosive effects when the slope degree is below 10°and even when it is above 30°, so we can consider the lawn have better effects.
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