| Soil respiration rates under four land use patterns in the red soil region of Changsha-Zhuzhou-Xiangtan region were measured by the lye (NaOH) absorption method during the non-growing season of December 2011 to May 2012. Differences in soil respiration under the four land use patterns and the relationships between soil respiration and air temperature and soil water contents were analyzed. The results showed that deily changes of soil respiration presented single peak curves，and that of air temperature followed a similar trend. Paddy field and non-irrigated farmland had the highest values at noon, while land of pinus massoniana and grassland had the highest values in the evening. Seasonal changes of soil respiration presented increasing trend from December to May as a whole. But soil respiration rate of land of pinus massoniana in January less than that in December, and so does in April less than in March. As to respiration rate of grassland in February less than that in January and so does in April lower than in March. Estimating the soil respiration gave CO2 effluxes from grassland, land of pinus massoniana, paddy field and non-irrigated farmland, during the non-growth season, of 0.45,0.277 805,0.228 144,0.210 406 g·m-2·h-1, respectively. The results also show that air temperature, soil temperature, humidity, vegetation growth characteristics, biological and human activities are closely related to CO2 respiration. |
