利用皇竹草生态固化浅表层疏浚土试验研究

Experimental study on ecological solidification on shallow layer of dredged soil using Pennisetum hydridum

利用植物根系兼具吸水和加筋作用的特性,依托某疏浚工程,对利用皇竹草生态固化浅表层疏浚土进行现场试验研究。通过观测试验区内浅表层(0~90 cm深度)疏浚土含水率、承载力、土壤养分含量及重金属含量的变化,分析和评价皇竹草生态固化浅表层疏浚土的效果。研究发现:1)皇竹草种植完成85 d后,种植区土壤承载力由11.8~27.7 kPa增加至54.5~68.3 kPa,而空白对照区仅为33.4 kPa;2)疏浚土中的有机质、碱解氮和速效磷含量分别增加了25.5%~43.9%、6.5%~17.0%、1.5%~9.6%;3)皇竹草对重金属Cu、Zn、Pb、Cd、Ni均具有吸附效果,其中对Cd的吸附效果最为明显。结果表明:利用皇竹草生态固化浅表层疏浚土是可行的,它能加速浅表层疏浚土的失水,快速固化浅表层疏浚土,尤其对30~90 cm深度范围效果明显;此外,皇竹草还具有提高土壤养分含量、吸收重金属的改良效果。

Considering the advantage of plant roots of both water absorption and reinforcement,and relying on a dredging project,we carry out the field experiment on the use of Pennisetum hydridum for the ecological solidification of the shallow dredged soil.Observing the changes in water content,bearing capacity,soil nutrient content,and heavy metal content of the shallow dredged soil in the test area(depth of 0~90cm),we analyze and evaluate the effect of Pennisetum hydridum on the ecological solidification of the shallow dredged soil.It is found that 85 days after planting of the Pennisetum hydridum,the soil bearing capacity of the planted area increases from 11.8~27.7 kPa to 54.5~68.3 kPa,while the blank control area is only 33.4 kPa;The content of organic matter,alkaline hydrolysis nitrogen and available phosphorus increases by 25.5%~43.9%,6.5%~17.0%,1.5%~9.6%respectively;Pennisetum hydridum has an adsorption effect on heavy metals Cu,Zn,Pb,Cd,Ni.Among them,the adsorption effect of Cd is the most obvious.In conclusion,it is feasible to use Pennisetum hydridum to ecologically solidify the shallow dredged soil.It can accelerate the water loss of the shallow dredged soil and quickly solidify the shallow dredged soil,especially for the depth range of 30cm to 90 cm.In addition,the Pennisetum hydridum also has the improvement effect of increasing soil nutrient content and absorbing heavy metals.