干旱区生态环境知识资源中心

Soil respiration as a major flux in the global carbon cycle plays an important role in regulating soil carbon pools. Global climatic changes including warming and a changing precipitation pattern could have a profound impact on soil respiration of terrestrial ecosystems, especially in arid and semiarid region where water is limited. We conducted a field experiment to simulate precipitation changes in a Mongolian pine plantation at Horqin sandy lands. The results indicated that, soil respiration was significantly affected by reduced rainfall treatment and water addition treatment in 9 experiment plots. Soil respiration rates in the water addition treatment plots increased about 40.7% to 166.4% and decreased about 34.0% to 70.0% in the reduced rainfall treatment plots. A model of the relationships between soil respiration and moisture with temperature was obtained by an empirical equation. Through operating the model, it was indicated that the highest soil respiration rate occurred at high soil water contents and intermediate soil temperatures in 9 plots. In the combined responses of soil respiration to soil temperature and soil moisture, soil temperature as a single independent variable explained only 29.9% of variance in soil respiration, and soil moisture was 71.3% of variance in soil respiration. It was concluded from our results that precipitation compared with soil temperature dominated more significantly the variability of ecosystem soil respiration in semiarid sandy lands.