微生物固化粉土坡面的植物适生性研究

Plant adaptability of silty soil slope protected by microbial solidification

微生物固化粉土坡面能够提高粉土边坡的抗侵蚀能力,微生物固化防护层的物理力学特性以及植物的适生性是影响该技术应用的重要因素。采用巴氏芽孢杆菌以及胶结液对粉土进行表层喷洒固化处理,研究高羊茅和披碱草在微生物固化表层的粉土中的出苗生长情况。试验结果显示,提高胶结液浓度能够获得更高的粉土表层固化层强度。采用高浓度胶结液的固化层水稳定性更好。粉土表层经微生物固化后高羊茅和披碱草的出苗率随着固化层贯入阻力的提高而降低,出苗时间延迟4~5 d。固化层贯入阻力低于280 kPa时,出苗率可达到80%以上。采用菌液和浓度为0.75~1.00 mol/L、喷洒量0.06 mL/cm 2的胶结液喷洒3遍处理,可以保证粉土坡面既具有一定防护强度,又能够保证高羊茅正常生长。粉土经微生物固化表层后不适于披碱草的生长。研究结果表明,微生物固化粉土坡面对草本植物具有一定的适生性;植物种类及固化层强度是影响出苗率和出苗速率指数的重要因素。将微生物坡面防护与植物防护相结合的粉土坡面防护技术有良好的发展潜力。

Microbial solidified surface layer can improve the anti-erosion stability of silt slope.The physical and mechanical properties of microbial solidified silt protective layer and the plant adaptability are important factors to affect the application of this technology.Sporosarcina pasteurii and cementing solution were used to spray and solidify the silt on the surface.The penetration resistance,water stability and cementing calcite content of the solidified layer were tested to ascertain the effects of different microbial solidifying parameters.The seedling growth of herbaceous plants was investigated for its adaptability properties in the silt surface layer solidified by microbial method.The experimental results indicated that the higher concentration of cementing solution could obtain the higher strength of solidified layer on the silt surface.The water stability of solidified layer formed by the high concentration cementing solution was better.The seedling emergence rate of Festuca elata Keng ex E.Alexeev and Elymus dahuricus Turcz.was decreased with the increase in penetration resistance of the curing layer,and the seedling emergence time was delayed by 4 d to 5 d.In addition,when the penetration resistance of solidified layer was lower than 280 kPa,the emergence rate was over 80%,which could meet the needs of germination and growth.On the other hand,the penetration resistance of solidified layer which was higher than 280 kPa was not suitable for seedling growth of F.elata Keng ex E.Alexeev.The microorganism solidifying treatment with the cementing solution concentration of 0.75-1.00 mol/L and the spraying amount of 0.06 mL/cm 2 for 3 times could ensure that the silty soil slope had enough protective strength and the normal growth of F.elata Keng ex E.Alexeev.However,the microbial solidified silt showed a significant adverse effect on the growth of E.dahuricus Turcz.seedlings.E.dahuricus Turcz.couldn t adapt the soil conditions of surface layer solidified by the microbial method.The results showed that the microbial solidified silt slope had an ecological compatibility with some herbaceous plants.Plant species and strength of solidified layer were important factors of plant adaptability.The solidified layer hindered the growth of seedlings,resulting in a decrease in seedling emergence rate and the delay of emergence time.The combined technology of microbial slope protection and plant protection had a great potential in the silty soil slope protection.