Temporary responses of soil respiration to precipitation in simulated typical steppe on the eastern Gansu Loess Plateau

Precipitation is one of the key factors that influence the soil respiration. A simulated precipitation experiment focused on effects of precipitation on soil respiration was conducted in the steppe in southeastern Gansu Province in 2012. The results showed that: soil respiration rate (Rs) increased sharply after 15 mm and 30 mm precipitation and Rs was 9.0 times and 10.3 times higher than that of no-precipitation treatment in sunny aspect. Rs of grassland with 30 mm precipitation was higher than that of with 15 mm precipitation significantly (P0.05). In shady aspect of grassland, Rs increased 5.2 times and 8.0 times compared with no-precipitation treatment when precipitation was increased 15 mm and 30 mm, respectively. None significant differences of Rs were found between precipitation and no-precipitation treatments after 5 hours. Soil CO2 emissions were increased 2~3 times after the precipitation. The excitation effects of precipitation on Rs should be considered when evaluating the amount of CO2 emitted from soil. It is essential to adjust the soil CO2 emission data based on precipitation.