干旱气候对白羊草群落地下部生长影响的初步观察  

Effect of arid climate on underground growth of Bothrichloa ischaemum community.

作　　者：张娜[1] 梁一民[2] 

机构地区：[1]中国科学院研究生院地学部,北京100039 [2]中国科学院水土保持研究所,杨凌712100

出　　处：《应用生态学报》2002年第7期827-832,共6页Chinese Journal of Applied Ecology

基　　金：国家"九五"科技攻关项目 ( 96 0 4 0 5 0 4)

摘　　要：对大旱之年白羊草 (Bothrichloaischaemum)群落地下部的生长状况与 1 991平水年该群落地下部的生长状况进行比较 ,以反映干旱气候对白羊草群落地下部生长的影响 .结果表明 ,极旱年地下生物量的峰值达到 1 2 4 9g·m-2 ,比平水年峰值 5 86g·m-2 高 1倍多 .在极旱年或旱季根系主要集中分布的层次下移 ,而在平水年或雨季则上移 .极旱年群落地下生物量的周转值为 5 2 .6 4 % ,显著高于平水年时的周转值1 8 36 % .极旱年群落的地下生物量与地上生物量在生长中后期互为消长关系 ,而平水年两者在生长季同时增加 ,基本呈直线关系 .极旱年群落的地下生物量与地上生物量比为 1 1 .1 9,显著高于平水年时的比值2 .0 3 .极旱年群落的地下净初级生产量为 390 .7g·m-2 ·年 -1 ,比平水年时的生产量 1 0 7.6 g·m-2 ·年 -1 高2 .6The underground growth of Bothrichloa ischaemum community in extremely arid year were compared with that of the community in 1991 with normal precipitation, and hence, could reflect the effect of drought on underground growth of Bothrichloa ischaemum community. The results indicated that the peak value of underground biomass reached 1249 g·m -2 in extremely arid year, higher than that in normal year (586 g·m -2 ). Most roots distributed downwards in extremely arid year or arid seasons, and distributed upwards in normal year or rain seasons. The turnover rate of underground biomass in extremely arid year was 52.64%, significantly higher than that in normal year (18.36%). In extremely arid year, underground part and aboveground part competed with each other at the middle and later stage of growth, however, in normal year, they increased simultaneously presenting beeline correlativity on the whole. The biomass ratio of underground to aboveground in extremely arid year was 11.19 and significantly higher than that in normal year (2.03). Net underground primary production in extremely arid year was 390.7 g·m -2 ·yr. -1 and 2.63 times higher than that in normal year.

关 键 词：干旱气候 白羊草群落 根系 生物量 

分 类 号：S812[农业科学—草业科学]