冰冻灾害前后矿区废弃地栾树杜英混交林生态系统养分含量的比较

对冰冻灾害前后湖南湘潭锰矿矿区废弃地的栾树、杜英混交林生态系统的地表水、土壤、林木及死地被物的养分含量进行对比研究.结果表明:冰冻灾害后,林地地表水的pH值、电导率、溶解氧、K、Ca、Mg含量明显减少,Zn、Mn、Pb含量显著增加;林内土壤含水量、全P、全K含量显著增加,速效N、速效P、速效K含量明显减少,微量元素Cu、Pb、Co含量增加,Fe、Zn、Mn、Cd、Ni含量减少;林木枝、叶、干中含水量均显著减少,树干中N、P、Ca、Mg、Cu、Zn、Mn、Cd、Ni、Pb、Co含量增加,树枝和树叶中P、K、Mg减少,而Cu、Fe、Zn、Mn、Cd、Ni、Pb、Co含量却增加;林地上的死地被物中K、Mg在各组分(未分解、半分解、已分解)含量降低,Cu、Fe、Mn、Ni、Co含量增加.可为突发性自然干扰对植物生命活动的影响及抗御机理的研究提供基础数据.

Impact of Freezing Disaster on Nutrient Content in a Koelreuteria paniculata and Elaeocarpus decipens Mixed Forest Ecosystem

Little is known about changes in mineral nutrients in forest ecosystems after a severe freezing hazard.Quantitative differences of nutrient content in tree,litterfall,soil and surface runoff before and after recent freezing disaster were investigated in a Koelreuteria paniculata and Elaeocarpus decipens mixed forest ecosystem in an abandoned manganic mining site in Xiangtan,Hunan Province.The results showed that after the freezing disaster,pH value,electrical conductivity,dissolved oxygen and concentrations of K,Ca,Mg significantly decreased,while the concentrations of Zn,Mn,Pb significantly increased in surface runoff;soil water content and concentrations of P,K remarkably increased,while concentrations of available N,available P,and available K statistically decreased;the concentrations of microelements Cu,Pb,Co increased,and concentration of Fe,Zn,Mn,Cd,Ni declined in soils.The water content in twig,leaf and stem significantly decreased.The concentrations of N,P,Ca,Mg,Cu,Zn,Mn,Cd,Ni,Pb,Co in the stem increased,and the concentrations of P,K,Mg in the twig and the leaf decreased,while concentrations of Cu,Fe,Zn,Mn,Cd,Ni,Pb,Co increased.The concentrations of K,Mg decreased,while contents of Cu,Fe,Mn,Ni,Co increased in un-decomposed,semi-decomposed,and full-decomposed litter components.This study indicated that the freezing disasters had significant influence on nutrient storage and dynamic in forest ecosystems,and provided a basic knowledge about influence of the unexpected natural disturbance on plant community,and resistant mechanism of forest ecosystem as well.