东北羊草草原综合生态因子对微生物生长的作用──IRM模型的研究

STUDY ON THE ACTION OF MULTI-ECOLOGICAL FACTORS ON MICROBIAL GROWTH IN THE LEYMUS CHINENSIS GRASSLANDS IN NORTHEAST CAINA AND THE IRM MODEL

本文从分解者亚系统水平研究了东北羊草草原土壤中微生物生长的季节变化．多种生态因子的季节变化及环境因子对微生物的综合作用规律。微生物总数，总生物量和总呼吸强度的季节动态呈单峰上凸式曲线变化，８月份有明显的高峰值出现，它们分别为：２６８９．０×１０￣４个／ｇ·干土、２５．４１×１０￣（０３）ｇ／ｇ·干土、０．８９５２×１０￣（－３）ｇＣＯ＿２／ｇ·干土·ｄ。土壤生态因子的季节变化与土壤微生物呈现不同程度的正相关和负相关。同时利用ＩＲＭ的模型─—探讨了生态因子对微生物生长的综合作用规律：生态因子对微生物生长的综合作用指数ｒ＿ｎ在整个生长季节中为０．００３１８－０．１１１５，其中７－９月份ｒ＿ｎ较大，对出生物生长的限制作用较小，微生物生长较快，５、６和１０月份ｒ＿ｎ较小，对微生物生长限制作用较大，微生物生长较慢。

he patterns of seasonal variations in the growth of microbes,the multi-environmental factors,and the integrated effects of the factors on soil microbes in the Leymus chinensis grasslands,were studied on the decomposer microbes subsystem.The number of microbes,the biomass and the respiration intensity were found to vary seasonally by following a relief curve with the peak values occtirred in August,which were 2689.0×10￣4/g(dry soil),25.41 ×10￣(-3)g/g(dry soil),and 0.8952×10￣3gCO_2d·g(dry soil),respectively.The seasonal varia- tions in soil miosture,soil temperature,active organics,hydrolytical nitrogen and quick-act- ing phosphorus and electrotical conductivity in soil varied in a way contrary to that for mi- crobes,with the mininum values occurred in August.In addition,the integrated effects of environmental factors on microbes were also studied with the IRM model:The integrated action index of environmental factors was defined as r_n,which ranged from0.00318 to 0.1115,wich higher values occurred in the period form July to september duringwhich there were more inhibitory effects on microbes,and lower values occtirred in May,June and October during which there were less inhibitory effects on microbes.