羊草和大针茅凋落物分解及其微生物学效应

本文对锡林郭勒草原的主要建群种羊草(Aneurolopidium chinense)和大针茅(Stipa grandis)凋落物的分解状况与各类群腐解微生物生物量动态变化以及凋落物分解对其相应土层的生物活性影响进行了初步研究。研究结果表明： 1．羊草和大针茅凋落物(茎、叶)的分解速率均较缓慢。二年来地表样的失重率分别为15.9%、16.9%和21.5%；埋置样分别为21.4%、23.5%和26.5%。其埋置凋落物分解速率高于地表层。2．凋落物腐解过程中各类群腐解微生物生物量均有明显上升，与凋落物(起始)表面附着微生物的生物量相比，其上升幅度多在10—300倍之间。3．两年中凋落物残体的碳、氮含量比值随腐解进程而下降。4．凋落物的腐解可以刺激相应土层的土壤微生物活性的增长，而且其土壤有机质含量亦有提高。

THE MICROBIOLOGICAL EFFECT AND DECOMPOSITION OF LITTER OF ANEUROLEPIDIUM CHINENSE AND STIPA GRANDIS

This paper is a perliminary study of the decomposition of litter of theXilinguole grassland major plants Aneurolepidium chinense and Stipa grandisand the dynamic changes of biomass of various of decaring microorganis-ms, and the effect of soil biology with decomposing litter. The study results shows: 1. The decomposing rate of litter of Aneurolepidium chinense and Stipagrandis stems and leaves is comparatively slow. The weight loss rateswere respectively 15.9%, 16.9% and 21.5% on soil aboveground; In soilunderground they were 21.4%, 23.5% and 26.5% in the past two years.And the decomposing rate became more and more slow with the passageof time. The decomposing rate of litter in soil underground is higher thanthat on the soil aboveground. 2. In the process of decomposition of litter, the biomass of the various groups of microorganims increased markedly. Compared with microbial bio-mass sticking to the surface of litter, progress increase ranged from 10 to300 times. 3. The ratio of the carbon content to the nitrogen content of the rot-ting residues decreased with the progress of decomposition. 4. Decomposition of litter could stimulate the increase of microbiolo-gical activity in soils of different depths, and an increase of soil organiccontent as well.