Litter And Decomposition Of Spatio-temporal Dynamics Of Celtis Sinensisshelter In Langqi,Minjiang Estuary

Taking Celtis sinensis shelter in Langqi Island which is located at Minjiang Estuary of Fuzhou as research object,the paper has tracked and studied the amount of shelter litter and its decomposition process for one year,meanwhile roughly studied the water holding capacity of litter and the ecological function of the allelopathic effect.The pape r is aimed at revealing impact that the litter in Celtis sinensis shelterbelt and has on its ecosystem habitats specially comparing litter,nutrient content,decomposition rate betwe en forest gap and understroy,provide basic data for sustainable management of the coast wise shelterbelt.The research results are as follows:1,The total amount of litter Celtis sinensis Shelter per year is 5.910×103kg/hm2,whose dynamic change shows a bimodal pattern;there is a significant difference in total annual litter between the forest understory and the forest gap that the total annual litter in forest gap is less than that in forest understory;which the total annual litter in the west of gaps is maximum while the middle is minimum.2,The proportion offour components in little vary widely,and the order according to their proportion is as follows:leaves>falling branch>debris>fruit.3,Nutrient content of fresh litter like C,N,P,K,Ca,Mg in the microhabitats of gaps and understory roughly have a same variationtendency,indicating that nutrient content in fresh litterhas nothing to do with their location but nutrient content of their own.4,According to their annual return amount,the ranking result of 6 kinds of macroelements is:C>Ca>N>K>P>Mg;the annual return amount of gaps and understory are proportional to the amount of their little in the microhabitats.5,The little decomposes much more quickly in the forest gap than in the forest understory and the nutrient changes of the macroelements during decomposition can be summarized as follows:the macroelements C,N,P and Ca show a progress from leaching to enriching and finally to releasing;the macroelements K and Mg show a progress simply from leaching to releasing.The decomposition rate has a negative correlation with C/N.6,On litter decomposition and activity study founds:enzymatic activity inforest gaps microhabitats is higher than in understory microhabitats.Forest gaps microhabitats adequate light and the soil surface covering less than understory litter microhabitats for gaps microhabitats whichi provide good illumination conditions and soil respiration,so soil invertase,urease activity in forest gapswere higher than understroy microhabitats.7,The soaking time of the little has a significant positive correlation with its water holding capacity and has a slightly negative correlation with water-absorption rates;the water holding capacity of little shows a significant negative correlation with its water-absorption;the relationship between water-holding capacity and Soaking time is:W=196.4681n(t)+1262.545,whose R2 is 0.990;the relationship between water-absorption and soaking time is:V=1.243t-0.858,whose R2 is 0.999.8,The germinationrate of Celtis sinensis seed varies among different extractconcentration of Celtis sinensis leavesand Radix Ophiopogonis leaves.The extract concentration of Celtis sinensis leaf which is below 0.500 g/mL can promote Celtis sinensis seed germination,while it will inhibit seed germination when the extract concentration is higher than 0.500 g/mL.Celtis sinensis germination rate isincreased with the decreasing of extract concentration of Radix Ophiopogonis leaves:the extract concentration of 0.500 g/mL and 0.750 g/mL show a weaker seed germination effect than the extract concentration of 0.250 g/mL.The extract concentration of Radix Ophiopogonis leaves shows a stronger allelopathic effect than that of Celtis sinensisleaves with the same concentration.