垃圾堆填区渗出液对干旱季节树苗生长的影响

本试验于１９９４年７月至１月在香港望后石垃圾堆填区进行，研究了垃圾堆填区渗出液浇灌对几种亚热带树种生长及其生理学过程的影响．结果表明，在高温低湿、植物遭受水分亏缺的条件下，应用适当浓度的垃圾堆填区渗出液浇灌同水灌和肥水灌溉类似，可显著地提高树苗的移栽成活率，促进树苗的生长，尤其对耐干旱能力低的树种，其效果更为显著．与对照相比，用适当浓度的渗出液或水浇灌显著地改善植株的水分关系，降低叶片的脱落酸（ＡＢＡ）含量，促进气孔的开放．另外，处理植株叶片的光合特性也得到了不同程度的改善．根据以上结果，作者认为，在干旱季节植物遭受严重水分亏缺的条件下，应用适当浓度的垃圾堆填区渗出液浇灌可显著地缓解干旱对树苗生长的影响，为综合治理垃圾堆填区渗出液提供了一条经济、实用和可行的途径．

EFFECTS OF LANDFILL LEACHATE IRRIGATION ON THE GROWTH OF SUBTROPICAL TREES DURING DRY SEASON

The effects of diluted landfill leachate on growth, survival rate and physiological aspects of sub tropical trees, Acacia confusa, Syzygium jambos, Eucalyptus torelliana, E. robusta , and Leucaena leucocephala were investigated on Pillar Point landfill site, Hong Kong during the dry season and compared with watering and fertilizer application treatments. The responses of growth and survival to soil drying varied greatly with tree species. A. confusa had relatively high growth and survival rates, even under severe soil drying conditions , whereas a high mortality and low growth rate was observed for S. jambos under the same conditions . Landfill leachate irrigation significantly improved the survival rate and stimulated tree growth, especially for the species more susceptible to water stress, such as S. jambos and E. robusta . Similar effects were observed following the treatments of watering and fertilizer application. Leaf water potential and stomatal conductance decreased steadily, and leaf abscisic acid (ABA) content increased, as the soil drying progressed. Watering, fertilizer application and leachate irrigation all improved water relations of trees, stimulated stomatalopening and reduced leaf ABA contents. Furthermore, the photosynthetic performance of trees was also improved after imposition of the treatments. The results from this study showed that during the dry season when trees were subjected to severe water stress, landfill leachate irrigation could alleviate the impacts of soil water stress on trees. The possibility of landfill leachate re circulation using low cost technology is also discussed.