EFFECTS OF LAND DEGRADATION AND REHABILITATION ON VEGETATION CARBON AND NITROGEN CONTENT OF ALPINE MEADOW IN CHINA
EFFECTS OF LAND DEGRADATION AND REHABILITATION ON VEGETATION CARBON AND NITROGEN CONTENT OF ALPINE MEADOW IN CHINA
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DOI：
10.17521/cjpe.2007.0135
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发表时间：
2007-11
影响因子：
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通讯作者：
Wang Qi-ji;W. Wenying;Jing Zeng-chun;W. Gang
中科院分区：
文献类型：
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作者：
Wang Qi-ji;W. Wenying;Jing Zeng-chun;W. Gang
目的比较严重退化草地与原状草甸植被生物量和总碳氮含量的差异，以及不同恢复措施对次生演替早期植被生物量和碳氮含量的相对影响。方法以青海省达里县高寒草甸为研究对象，采用原状草甸、严重退化草甸和混合播种、单一播种和自然恢复3种不同恢复方式的草地5种处理方式。在每个处理中，根据生物量样品和植物浓度分析，按面积和深度计算植被C和N含量。未受干扰的天然草甸处理，地上总生物量为265.1 g·m-2，最上层30 cm根系生物量平均为6 982 g·m-2。在严重退化草地处理中，地上生物量仅为139.9 g·m-2，根系生物量仅为916 g·m-2。7个生长季节后，混合、单播和自然恢复处理的地上总生物量分别为307.11、179.9和200.4 g·m-2，根系总生物量分别为1 323、1 169和1 412 g·m-2。未受干扰原生态草甸植被总碳含量为3 067.42 g·m-2，而严重退化草地植被总碳含量仅为414.07 g·m-2。因此，土地退化导致86.5%的原始植物组织C损失，68.3%的原始植物组织N损失，与严重退化土地相比，混合种子和自然恢复处理部分恢复了C和N含量，表明它们可能是原退化高寒草甸固碳的替代途径。
Aims Our objectives were to compare vegetation biomass and total carbon and nitrogen content of severely degraded grassland and undisturbed Kobresia meadow,and to measure the relative influence of various rehabilitation practices on vegetation biomass and carbon and nitrogen content in early secondary succession.Methods The research was conducted on alpine meadows in Dari County,Qinghai Province,China,using five treatments:undisturbed native meadow,severely degraded grassland,and three grasslands rehabilitated by different practices(mixed seeded,single seeded and natural recovery).In each treatment,vegetation C and N contents were calculated on an area and depth basis from biomass samples and plant concentration analyses.Important findings In the undisturbed native meadow treatment,total aboveground biomass was 265.1 g·m-2 and root biomass in the uppermost 30 cm averaged 6 982 g·m-2.In the severely degraded grassland treatment,above ground biomass was only 139.9 g·m-2 and root biomass was only 916 g·m-2.Total aboveground biomass in the mixed seeded,single seeded and natural recovery treatments was 307.1,179.9 and 200.4 g·m-2,and root biomass was 1 323,1 169 and 1 412 g·m-2,respectively,after seven growing seasons.Total C content of vegetation in the undisturbed native meadow was 3 067.42 g·m-2,while that of the severely degraded grassland treatment was only 414.07 g·m-2.Therefore,land degradation leads to loss of 86.5% of the original plant tissue C.In addition,land degradation leads to loss of 68.3% of the original plant tissue N.Compared with the severely degraded land,mixed seeded and natural recovery treatments partly recover C and N content,indicating that they may be alternative approaches to sequestering C in former degraded alpine meadow.