Effects Of Stimulated Warming And Nitrogen Deposition On Soil Respiration In A Desert Steppe Of Inner Mongolia

The surface temperatures of Earth and atmospheric N deposition have continued to increase due to human activities, which could directly affect vegetation, soil and global ecosystem carbon cycling. As one of the important systems, terrestrial systems play an important role to regulate and feedback effects to global climate change. The study relies on the experimental base of Inner Mongolia Siziwangqi desert sreppe pastoral Academy as a research platform, the variation of soil respiration rate was studied under warming and N addition in the desert steppe. According to the study of global change and desert steppe ecosystem relationship, a reliable theoretical basis was provided. The study was initiated in June2006with a randomized block split-plot design, warming treatments (with or without warming) as the main factor and nitrogen (N) addition treatments (addition nitrogen fertilization and natural control) as the sub-factor. The important findings are as follows:1. Compared with CK, both warming and its interactions with N addition significant increased0-10cm,10-20cm and20-30cm soil layer temperature, whereas N addition was no change the temperature of different soil layer both in2010and2011. The soil layer moisture between the warming and its interactions with N addition had no significant effects. The significant positive linearly correlation were detected between soil respiration and0-10cm soil temperature.2. Almost unanimous variable tendency were detected between soil respiration rate and monthly accumulated precipitation in plant growth season, and the maximum value of soil respiration was showed in plant peak growth period. The soil respiration value was higher in warming x N addition than other treatments in cold September and October, whereas different treatment can promote soil respiration in relatively good hydrothermal month.3. During the experiment period, the daily dynamic change tendency of soil respiration was the same in the different treatment which showed a one-peak curve with the higher value in the day and the lower value in the night. In the two years, the maximum value of soil respiration rate appeared at15:00in warming x N addition and the minimum of soil respiration appeared at00:00in N addition. The value of soil respiration rate was highest in warming x N addition by observing the daily mean soil respiration rate under different treatment. Our results also indicated that soil respiration had a positive relationship with both10cm soil temperature and air relative moisture by Li-8100automatic measured.