| Moso bamboo(Phyllostachys edulis(Carriere)J.Houzeau)is an important forest resources,however,due to the rapid growth,the adaptability and other biological characteristics,the expansion potential is huge,and the ecological effect of moso bamboo expansion is expanding.The systematic research on the invasion of broad-leaved forest by moso bamboo was carried out in different ways by most scholars,but the research on coniferous forest is less.In this paper the moso bamboo invasion of coniferous forest typical area in lushan nature reserve as the research object,to study the effects of forest types and elevation on forest litter,soil rapid nutrient and soil microorganism and its correlation.The purpose of this study was to reveal the influence of the moso bamboo invasion on the soil's quick acting nutrients and its microbiology,and the response of the coniferous forest to the invasion of moso bamboo.According to the proportion of the bamboo invasion coniferous forest,the two-factor randomized block experiment was set up,with six elevation gradients and three types of forest types.That is,the three different altitude gradients of the moso bamboo pure forest(bamboo proportion>80%)in three different elevation gradient,bamboo-needle mixed forest ratio of 6:4(bamboo needle of 6:4-5:5),coniferous pure forest,(needle proportion>80%)of the two kinds of different elevation gradient,a total of six elevation gradient of three forest types.Forest litter and soil samples of different forest types were collected for the determination of biomass and nutrient index.These results show that:(1)The expansion of the moso bamboo resulted in the transformation of coniferous forest into bamboo-needle mixed forest,forest biomass of litters?total carbon and the rate of C:N were significantly reduced(p < 0.05);but the total nitrogen of litters,the ratio of N:P increased significantly(p < 0.05).The effect of the overall effect on the biomass,nutrient content and stoichiometry of the litter was significant(p < 0.05).(2)The expansion of moso bamboo leaves the coniferous forest into bamboo-needle mixed forest,the content of ammonium nitrogen was significantly increased.The effect of altitude change on ammonium nitrogen and nitrate in soil was significant.The effects of forest type and elevation on ammonium nitrogen,available phosphorus and organic matter were significant.(3)Moso bamboo invasion of coniferous forest has no significant effect on the number and total content of soil microbial phospholipid fatty acids,however,the content of phospholipid fatty acid in gram-positive bacteria was significant.In the process of moso bamboo invasion of coniferous forest,obviously reduce the richness of the soil microbial phospholipid fatty acid and phospholipid fatty acid composition of evenness,and did not significantly change the composition of soil microbial advantage strain group.The influence of forest type on the stress index(sat:mono)was significant,indicating that the invasion of bamboo was damaging the original environment of soil microorganism,but it had no significant effect on the whole community.(4)The correlation between soil microorganism and litter nutrients and soil available nutrients showed that,the total carbon content of litters could promote the content of some species of soil microorganisms in the soil.If the total nitrogen content of litter is too high,it will inhibit the survival and reproduction of soil microorganisms.The available nitrogen,nitrate nitrogen and available phosphorus content of soil have inhibitory effect on some bacteria,actinomycetes and protozoa species.In addition,the content of ammonium nitrogen has a positive effect on some gram-positive bacteria,and the content of organic matter promotes and inhibits two different effects. |
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