Abstract: Calorific value and energy of sward and efficiency for solar energy utili-zation were determined during June to Noverber on Tianzhu alpine Kobresia capillifolia grassland.Outlinets of the results were as follows:1.The average calorific value of standing green was 19186.03j/g DM (20797.88 OM)and ranged from 13888.46 to 9466.47j/g DM (20500.10 to 21223.11 OM),it was higher than standing dead+litter,live roots or dead roots,while live rootshigherthan dead roots.There were some seasonal fluctuations of calorific values,the highest values of the standing green and standing dead+litter and lowest values of the live and dead roots were all in August.2.Maximum standing calorie of aboveground,underground and whole phyto-mass occurred on August 21,June 21 and October 23 and values of them was 6920.53,84968.62 and 937444.09kj/m².yr.,respectively.Net calorie accumulation of aboveground and underground and whole sward was 6314.85,16818.44 and 14842.39 kj/m².yr.,respectively.Becouse maximum standing calorie of both above ground and underground was not appearance in the same time,so net calorie ac-cumulation of whole sward was not sum of them.3.Conversion efficiency for solar total radiation utilization of aboveground,underground and whole sward was 0.110%,0.303% and 0.258%,respectively.Ef-ficiency of aboveground for physiological radiation of visible light was 0.224% and for photosynthetically available radiation during growth season was 0.404%. Maximum efficiency of aboveground for total radiation could reach to 0.464%occurred on July 20 to August 21.

Key words: alpine, Kobresia capillifolia grassland, calorific value, standing calorie, conversion efficiency for solar radiation.

摘要： 甘肃天祝金强河地区高山线叶嵩草草地6—10月绿色活体的平均热值为19186.03焦/克干物质,或20797.88焦/克有机物质。立枯物+凋落物(6—11月)、活根和死根(6—10月)的平均热值均低于绿色活体。草层的最大热量现存量,地上部分是在8月,地下部分是在6月,全草层(地上+地下部分)是在10月出现,分别为6920.53,93311.89和101444.09千焦/米²。地上、地下部分热量净积累分别为6314.85和16818.44千焦/米²·年,而全草层的热量净积累为14842.39千焦/米²·年。地下部分的热量现存量在各时期均远大于地上部分,它是草地生态系统中主要的热量库,对能量的流转和地上部分的生长具很大的调节作用,并且是草地耐牧性的物质基础。草地对太阳总辐射的光能转化率地上部分为0.110%,地下部分为0.303%,全草层为0.253%;地上部分对可见光生理辐射的转化率为0.224%,≥0℃—≤0℃生长季的光合效率为0.404%。

关键词: 高山, 线叶嵩草草地, 热值, 热量现存景, 光能转化率