JOURNAL OF NATURAL RESOURCES ›› 2006, Vol. 21 ›› Issue (3): 458-464.doi: 10.11849/zrzyxb.2006.03.016

• Special Column:Celebration of the 70th Anniversary of IGSNRR, CAS • Previous Articles     Next Articles

Quantification of Soil Heterotrophic Respiration in the Growth Period of Alpine Steppe-Meadow on the Tibetan Plateau

ZHANG Dong-qiu1,2, SHI Pei-li1, HE Yong-tao1, XU Ling-ling1,21, ZHANG Xian-zhou1   

  1. 1. Institute of Geographic Sciences and Natural Resources Research,CAS,Beijing 100101,China;
    2. Graduate School of Chinese Academy of Sciences,Beijing 100049,China
  • Received:2005-11-04 Revised:2006-01-06 Online:2006-06-25 Published:2006-06-25

Abstract: Qualification of soil heterotrophic respiration is an important component to estimate ecosystem carbon balance.However,it is difficult to directly measure and distinguish it from root respiration.The heterotrophic respiration of Steppe-Kobresia meadow ecosystem was measured in situ in Dangxiong county,central Tibet Autonomous Region by using Li 6400-09 soil chamber.Soil heterotrophic respiration had a strong correlation with soil temperature especially with that at 5cm deep.It indicated that soil temperature at a depth of 5cm was the key factor to determine soil heterotrophic respiration.We analyzed how the soil heterotrophic respiration by soil temperature was affected under different soil moisture regime during the growth period.The variation of soil heterotrophic respiration was differentiated into rainy seaspm(June through August) and dry season(May,September and October).The regression equations between soil heterotrophic respiration and 5cm soil temperature were Rh=0.106exp0.133T in rainy season and Rh=0.18exp0.0833T in dry season respectively.By estimating the soil heterotrophic respiration,the daily mean and total soil heterotrophic respiration were 2.4gCO2·m-2 and 219.6gCO2·m-2 in rainy season,and the value of Q10 was 3.8;While the daily mean and total soil heterotrophic respiration were 1.8gCO2·m-2 and 160.2gCO2·m-2 in dry season,and the value of Q10 was 2.3.The result suggested that soil heterotrophic respiration was more sensitive in rainy season than in dry season during the growth period.The soil moisture caused by rainfall patterns in different months played an important role in regulating the relationship between microbial heterotrophic respiration and soil temperature.Based on established models of soil heterotrophic respiration in relation to soil temperature,the amount of soil heterotrophic respiration was estimated as 379.8gCO2·m-2 in the growth period(May through October) of 2004.

Key words: Tibet Plateau, soil heterotrophic respiration, soil temperature, soil moisture, Q10