污泥堆肥对海滨木槿生长及元素吸收的影响

Effects of Sewage Sludge Compost on Growth and Elemental Uptake of Hibiscus hamabo

污泥含有丰富的植物生长所需的营养元素,污泥堆肥用于苗木的栽培基质是污泥处理的一种有效方式。采用盆栽控制试验,研究污泥堆肥对海滨木槿生长和元素吸收的影响,以期为污泥的合理利用提供科学依据。结果表明,污泥堆肥对海滨木槿株高、地径、根系和生物量均有显著的促进作用,且随着污泥施用量的增加,效果越显著。污泥堆肥促进海滨木槿叶片叶绿素的合成,抑制类胡萝卜素的合成,适量的污泥堆肥(体积比为污泥∶红壤土=1∶1或污泥∶红壤土=3∶2)对海滨木槿叶片的净光合速率、气孔导度、胞间CO_(2)浓度和蒸腾速率最有利。N、P、K的吸收和Cu、Zn、Cd的累积随污泥使用量的增加而增加,根部吸收的N、P和K大部分运输到茎和叶,供地上部分生长,Cu和Cd主要富集在根部,而Zn含量在根、茎、叶中差异不显著。污泥堆肥施用量对海滨木槿的重金属富集和转移系数有显著影响,海滨木槿的Zn和Cd富集和转移能力强于Cu的,并且不同污泥堆肥处理下Cd的富集系数都大于1,表明海滨木槿是重金属Cd富集高效的植物,有望用于Cd污染土壤的修复。因此,施用适量污泥堆肥能够显著促进海滨木槿的生长,海滨木槿对污泥堆肥有较强的适应性和耐性,能够有效地富集重金属。

Sludge is rich in nutrient elements indispensable to plant growth.Utilizing Sewage sludge compost as seedling growing substrate is generally recognized as an effective way to utilization of sludge.We investigated the impacts of application rates of sewage sludge compost on the growth and elemental uptake in Hibiscus hamabo by a pot experiment,in order to provide a reference for the rational utilization of sludge.The results showed that sewage sludge compost could significantly promote plant height,ground diameter,root system and biomass of Hibiscus hamabo,and the effect was more obvious with the increase of sewage sludge compost application.Sewage sludge compost could promote the synthesis of chlorophyll and inhibit the synthesis of carotenoids in the leaves of Hibiscus hamabo.Appropriate amount of sewage sludge compost(sludge∶laterite=1∶1,or sludge∶laterite=3∶2,volume ratio)was most favorable for the net photosynthetic rate,stomatal conductance,intercellular CO_(2) concentration and transpiration rate of Hibiscus hamabo leaves.The absorption of N,P and K and the accumulation of Cu,Zn and Cd increased with the increase of sludge use.Most of the N,P and K absorbed by roots were transported to stems and leaves for the growth of aboveground parts.Cu and Cd were mainly concentrated in roots,while Zn was not significantly different in roots,stems and leaves.The amount of sewage sludge compost had a significant effect on the heavy metal bioaccumulation and transfer capacity of Hibiscus hamabo.The enrichment and transfer ability of Hibiscus hamabo to Zn and Cd was stronger than that of Cu,and the concentration coefficient of Cd was more than 1 under different sludge compost treatments,indicating that Hibiscus hamabo is a plant with high concentration and efficiency of heavy metal Cd,which is expected to be used in the remediation of Cd contaminated soil.Therefore,appropriate amount of sewage sludge compost can significantly promote the growth of Hibiscus hamabo.Hibiscus hamabo has strong adaptability and tolerance to sewage sludge compost,and can effectively enrich heavy metals.