Influence of karst rocky desertification on soil carbon emissions in karst valley region of southwestern China.

Soil plays an important role in the global carbon balance, while soil carbon is sensitive to the change of land use. The paper addresses the scientific question that how will the land degradation and the decreasing of the quality of soil influence the soil carbon emissions, which was caused by the rocky desertification. We selected monitoring plots in the typical rocky desertification area of Huajiang Karst Gorge in Guanling County of Guizhou Province. We used the Li-8100 automated soil CO2 flux system to monitor the daily and seasonal variations of soil respiration from 2012 to 2013 in the fields via the monitored data analysis of the area and degrees of rocky desertification land of Guanling County before and after the rocky desertification management. The influence of rocky desertification management on soil carbon emissions was evaluated quantitatively. The research aimed to provide scientific basis for assessment of the influence of rocky desertification on soil carbon emissions. The research suggested that: 1) Soil respiration rate in rocky region had a very high concordance with the degree of rocky desertification, the higher the degree of rock desertification was, the lower the amount of soil respiration was, and the amount of soil carbon emissions of seriously significant rocky desertification land was half of that of non-rocky desertification land; 2) Soil respiration rate of non-rocky desertification land had obvious seasonal variations, while the soil respiration rate of rocky desertification land did not follow the rule of plant growth as the season went by, and the rule of soil respiration rate爷s seasonal variation was broken; 3)The regional soil carbon emissions was connected with the governance of rocky desertification, and that of Guanling County produced by soil respiration increased by 41 800 t when the rocky desertification management was implemented from 2005 to 2010, which was equal to 31.92 t/ km2 C increased in the karst region of this county.