A Comparison of the Vegetation/Soil Carbon Density and Net Ecosystem CO2 Exchange of Alpine Meadow with Different Enclosure Durations
Exclusion is one of the most promoted measures in grassland restoration.At present,it is necessary to study the vegetation-soil carbon density of alpine meadow with different enclosures.Based on monitoring 1-year,6-year and 16-year grazing exclusion plots,it is found that:1) the existing vegetation carbon density of alpine meadow with different enclosure durations is in the order of 16-year grazing exclusion plot (1 522.57 gC· m-2)＞ 1-year grazing exclusion plot (1 323.12 gC ·m-2) ＞ 6-year grazing exclusion plot (1 148.17gC · m-2),with a density variation statistically insignificant (P＞0.05); 2) the soil carbon density has a significant vertical distribution,with relatively high organic carbon density at 0～5 cm and 5 ～10 cm depths,soil organic carbon density greatly reducing downwards and soil bulk density increasing with depth.Moreover,the differences in soil organic contents and in soil bulk density are not statistically significant (P＞0.05) between different enclosure ages,but the soil carbon density at 040 cm depth has the order of 1-year grazing exclusion plot (28 636.32 gC · m-2) ＞ 6-year grazing exclusion plot (26 570.92 gC · m-2) ＞ 16-year grazing exclusion plot (26 060.71 gC · m-2).The soil bulk density reduces with enclosure age; 3) by monitoring the net ecosystem CO2 exchange (NEE) from lately July to early October,it is found that the soil carbon uptake rate of 1-year grazing exclusion plot is significantly higher than that of 16-year grazing exclusion plot (P＜0.05),but their release rates are almost the same,with a difference statistically insignificant (P＞0.05).
NETL
NSTL
万方数据
维普
