Variation Of Soil Respiration In Different Ecosystems And Their Relationship With Environmental Factors In The Horqin Sand

Horqin sandy land is one of the largest sandy, frequent human activities, the fragile ecological environment in China. The reports of soil respiration (Rs) were still rarely in the Horqin sandy, especially the Rs pattern under different ecosystems in the typical sand and meadow areas. This study selected four ecosystems which included bare soil in mobile dune, artificial poplar forest in sand and meadow transitional zone, reed-weed community in meadow land and Caragana microphlla community in fixed dune. To observe diurnal variation and monthly variation and related correlation factors of Rs in the growing season under different ecosystem.1. The results showed that diurnal variations of Rs in the same period were different under different ecosystem, and especially in mobile dune and artificial poplar forest the diurnal variations were significantly different.2. On 2014, the mean value of growing season Rs was 7.75μmol m-2 s-1,4.67μmol m-2 s-1 in artificial poplar forest, Caragana microphlla community respectively; in 2015, 1.32μmol m-2 s-1,6.70μmol m-2 s-1,9.04μmol m-2 s-1 in mobile dune, artificial poplar forest, and reed-weed community respectively. In 2014, the highest Rs coefficient of variation was in artificial poplar forest (40.17%) and the lowest in Caragana microphlla community (32.96%); in 2015, the highest in reed-weed community (66.58%) and the lowest in mobile dune (37.67%). The temperature sensitivity (value) in artificial poplar forest (2.60) was higher than that in Caragana microphlla community (1.40) in 2014; and Q10 in reed-weed community (2.83) was higher than that in artificial poplar forest (2.29) and mobile dune (1.28) in 2015.3. Seasonal peaks of Reserved litter and Remove litter appear in August for the artificial poplar forest and the C. microphlla community. Soil respiration of the artificial poplar forest is much higher than that of the C. microphlla community. Seasonal changes of soil respiration of the artificial poplar forest which changes in the Reserved litter are smaller than those of Remove litter. Seasonal changes of soil respiration of the C. microphlla community which unlike soil from the artificial poplar forest, changes in the Reserved litter are larger those of Remove litter.4. Although there were positive relationship between Rs and soil temperature, it was not significance in mobile dune and Caragana microphlla community. The relationship of Rs and soil moisture was significant negative correlation in reed-weed community, and significant positive correlation in mobile dune and Caragana microphlla community, and has reached the limits in artificial poplar forest. The model combined soil temperature and soil moisture did not improve capability to explain Rs, which compared with the model based on soil temperature or soil moisture only, except under reed-weed community ecosystem. These models improve capability to explain reserved litter better than remove litter.These results provided valuable information for understanding Rs under different adjacent ecosystems and reference for management desertification areas.