Abstract: Soil respiration is a key process in the carbon cycle for grassland ecosystems. The commonly-used methods for measuring soil respiration were introduced in this paper. The CO₂ flux in soil respiration for major grassland communities in the world and its relation to vegetation and climate were summarized and expounded. The impacts of land-use changes on soil respiration were discussed. Finally, the turnover and residence time of soil organic matter in the soils of different grasslands were compared.

Key words: peanut (Arachis hypogaea), root morphology, drought stress, soil layer, root activity.