海南橡胶林与热带雨林土壤微生物区系分析

Soil microflora analysis of rubber plantation and tropical rainforest in Hainan

【目的】研究热带橡胶林与热带雨林土壤微生物区系组成及其生物量,为海南地区橡胶林的生产提供理论参考。【方法】在海南地区分别选取5个橡胶林(儋州、琼中、乐东、万宁和海口)和5个热带雨林(五指山、霸王岭、尖峰岭、吊罗山和鹦哥岭)的样地,每个样地选择13个取样点,旱季和雨季总计260个样本,测定土壤的理化性质(pH、有机质、全氮、全磷和全钾);采用稀释平板分析法测定土壤中微生物数量(细菌、放线菌和真菌);采用线性回归分析方法分析土壤微生物区系、数量特征及其随季节的变化规律。【结果】比较橡胶林与热带雨林土壤的理化性质,二者仅pH差异不显著(P>0.05,下同),其他理化性质的差异均达显著水平(P<0.05,下同)。各样地间土壤有机质含量呈显著差异,鹦哥岭与其他样地pH差异显著;儋州与琼中、海口与吊罗山的土壤全氮含量无显著差异;儋州与五指山,琼中与乐东,吊罗山与鹦哥岭的土壤全磷含量无显著差异;乐东与霸王岭、琼中与尖峰岭的土壤全钾含量无显著差异;其他各样地的土壤全磷、全钾和全氮含量差异显著。样地土壤中不同微生物类群数量的排序为细菌>放线菌>真菌,细菌占微生物总量为95.46%~97.60%;在细菌和真菌数量上为热带雨林>橡胶林;放线菌数量上橡胶林>热带雨林。可见,橡胶林与热带雨林三大微生物类群差异均显著。土壤微生物总量上热带雨林>橡胶林;橡胶林各样地中微生物总量排序为乐东>琼中>儋州>万宁>海口,热带雨林各样地中微生物总量排序为鹦哥岭>霸王岭>吊罗山>尖峰岭>五指山。橡胶林和热带雨林中土壤微生物数量随季节变化差异明显,旱季到雨季细菌和真菌数量增大。回归分析结果表明,细菌、放线菌和真菌数量与土壤含水量呈极显著负相关(P<0.01,下同);细菌和真菌与pH无显著相关性,放线菌与pH呈极显著正相关;细菌和真菌数量与有机质呈极显著负相关,仅放线菌数量与有机质无显著相关性。【结论】季节变化对微生物数量造成显著影响。土壤理化性质、地上植被的不同均会对微生物数量产生影响,热带雨林能为细菌和真菌提供更有利的生长条件,橡胶林环境则有利于放线菌生长。要有足够的肥料施入及科学的田间管理相辅,以促进微生物活动将养分转化后供橡胶树生长发育。

【Objective】This paper investigated the difference of soil microbial flora composition and biomass between rubber plantation and tropical rainforest,and the results could provide reference value for the production of rubber plantation in Hainan.【Method】Five rubber forests(Danzhou,Qiongzhong,Ledong,Wanning and Haikou)and five tropical rain forests(Wuzhishan,Bawangling,Jianfengling,Diaoluoshan and Yinggeling)were selected as the research plots in Hainan.There were 13 sampling points in each plot,and a total of 260 samples in the dry and rainy seasons.Determine the physicochemical properties of the soil(pH,organic matter,total nitrogen,total phosphorus and total potassium),use the dilution plate analysis method to determine the number of microorganisms in the soil(bacteria,actinomycetes and fungi)and linear regressionanalysis to analyze the soil microbial flora and quantity characteristics and their changes with the seasons.【Result】By comparingsoil physicochemical properties ofrubber plantation and tropical rainforest,only the difference in pH value was not significant(P>0.05,the same below),and other differences were significant(P<0.05,the same below).There was significant difference in organic matter content among plots,only Yinggeling and other plots had significant differences in pH;only Danzhou and Qiongzhong,Haikou and Diaoluoshan had no significant differences in total nitrogen content.There was no significant difference in total phosphorus content between Danzhou and Wuzhishan,Qiongzhong and Ledong,Diaoluoshan and Yinggeling,and no significant difference between Ledong and Bawangling,and Qiongzhong and Jianfengling in total potassium content.There were significant differences in total phosphorus,total potassium and total nitrogen contents among other plots.The order of the number of different microbial groups was bacteria>actinomycetes>fungi.Bacteria accounted for 95.46%-97.60%of the total microorganisms.The bacterial and fungal contents were tropical rainforest>rubber plantation;the actinomycete content was rubber plantation>tropical rainforest.The differences in the three major groupsof between rubber forest and tropical rain forest were significant.The total amount of soil microorganisms was tropical rain forest>rubber forest.Theorder of total microorganisms in each plot of rubber plantation was Ledong>Qiongzhong>Danzhou>Wanning>Haikou,and the order of total microorganisms in various plots of tropical rain forest was Yinggeling>Bawangling>Diaoluoshan>Jianfengling>Wuzhishan.The number of soil microorganisms in rubber plantation and tropical rainforest varied greatly with the seasons,and the number of bacteria and fungi increased from the dry season to the rainy season.The number of bacteria,actinomycetes,and fungi showed extremely significant negative correlation with soil moisture content(P<0.01,the same below).Bacteria and fungi had no significant correlation with pH,and actinomycetes had extremely significant positive correlation with pH.There was extremely significant negative correlation between the number of bacteria and fungi and organic matter.Only the number of actinomycetes had nosignificant correlation with organic matter.【Conclusion】Seasonal changes have significant impact on the number of microorganisms.The difference in soil nutrient content and above-ground vegetation will affect the number of microorganisms.Tropical rain forest can provide more favorable growth conditions for bacteria and fungi,rubber forest environment is conducive to the growth of actinomycetes.Sufficient fertilizer application and scientific field management must be supplemented to promote the conversion of nutrients by microbial activities for the growth and development of rubber trees.