不同砍伐强度对花灌木重金属提取效率的影响

以重金属污染模拟试验场的6种花灌木为对象,进行不同伐桩高度和砍伐频次的处理,分析花灌木的萌枝特性、重金属质量分数和提取量。结果表明:不同伐桩高度和砍伐频次对夹竹桃、伞房决明和‘彩叶’杞柳的萌条生长和重金属提取量影响显著,而对‘红王子’锦带、木芙蓉和海滨木槿的影响不明显。为提高萌条生物量和重金属提取量,木芙蓉宜采用冬季重剪,贴地面进行,1 a砍伐1次;‘彩叶’杞柳采用冬季落叶期砍伐,伞房决明和夹竹桃宜采用春季萌芽前砍伐,均保留5~10 cm的留茬高度,2 a砍伐1次;‘红王子’锦带、海滨木槿可进行0~20 cm留茬高度的砍伐处理,频次可以1 a砍伐1次或2 a砍伐1次。

Effects of Different Cutting Intensities on Phytoremediation of Heavy Metal for Flowering Shrubs

The resprouting characteristics,heavy metal content and total phytoextraction amount of six kinds of flowering shrubs in heavy metal contamination trial site were studied by different stump height and cutting frequency.The stump height and cutting had significant effects on the resprouts growth and heavy metal uptake of Nerium indicum,Senna corymbosa and Salix integra‘HakuroNishiki’,but no significant effects on Weigela florida‘Red Prince’,Hibiscus mutabilis and Hibiscus hamabo.In order to increase the biomass of resprouts and phytoextraction of heavy metals,H.mutabilis should be harvested severely once a year on the grounding winter.S.integra,N.indicum,S.corymbosa should be harvested once every two years with 5-10 stump height.The optimal harvesting time of N.indicum and S.corymbosa was in spring before budding as well as S.integra in winter during deciduous period.W.florida and H.hamabo should be harvested once a year or twice a year with 0-20 cm stump height.