[Carbon sequestration characteristics and regional differences of typical warm and tropical grasslands in Henan Province, China.].

In this study, we examined the vegetation and soil carbon density characteristics and carbon distribution differences of four typical grasslands in two climatic zones, including warm-tempe-rate tussock (WT), warm-temperate shrub tussock (WS), tropical tussock (TT), and tropical shrub tussock (TS) in Henan Province. The results showed that the average aboveground biomass of grasslands was significantly higher in Northwest Henan (327.4 g·m) than that in South Henan (221.4 g·m), whereas the average root biomass in Northwest Henan (1.58X10 g·m) was significantly lower than that in South Henan (1.94X10 g·m). The average aboveground carbon density of grasslands in Northwest and South Henan was 113.75 and 77.35 g C·m, respectively. The aboveground carbon density of WT in Northwest Henan was higher than that of WS, though not statistically significant. The living biomass carbon density of TT was significantly lower than that of other grasslands in Southwest Henan. The average underground carbon density of grasslands in Northwest and South Henan were 6.35X10 and 5.14X10 g C·m, respectively. In Northwest Henan, there was no difference between WT and WS for both the root and soil carbon density. In South Henan, the root carbon density of TS was significantly lower than other grasslands, while the soil carbon density of TT was significantly higher than other grasslands. The average carbon density of grassland ecosystem in Northwest and South Henan was 6.46X10 and 5.22X10 g C·m, respectively. Soil was the main contributor of ecosystem carbon storage and accounted for about 78%-90% of total grassland ecosystem carbon density. In addition, there were no significant differences in the ecosystem carbon density between WT and WS in Northwest Henan, while TT possessed significantly higher ecosystem carbon density (9.70X10 g C·m) compared with other grasslands in Southern Henan. Our results provide basic data for accurately calculating ecosystem carbon storage and assessing carbon sequestration potential of different grasslands in Henan Province.