Short-term responses of a Stipa grandis/Leymus chinensis community to frequent defoliation in the semi-arid grasslands of Inner Mongolia, China
Short-term responses of a Stipa grandis/Leymus chinensis community to frequent defoliation in the semi-arid grasslands of Inner Mongolia, China
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DOI：
10.1016/j.agee.2009.03.002
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发表时间：
2009-07
期刊：
影响因子：
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通讯作者：
A. Schiborra;M. Gierus;H. Wan;Y. Bai;F. Taube
中科院分区：
文献类型：
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作者：
A. Schiborra;M. Gierus;H. Wan;Y. Bai;F. Taube
内蒙古半干旱草原因过度放牧而退化，造成了严重的生态和经济问题。发展可持续的管理系统是必要的，但是关于其形成和发展的退化过程的基本资料很少。2004年和2005年在内蒙古锡林河流域进行了刈割频率试验，对未退化草地区进行了生长季末单次刈割、6周刈割和3周刈割3种刈割频率试验。我们假设，大叶蝉/L的生产力。频繁的落叶会使柽柳群落减少。累积干物质产量随落叶频率的增加而增加，2004年为204 ~ 277gDMm−2,2005年为87 ~ 158gDMm−2。2005年地上生物量生产力低的主要原因是降水量少，仅为长期平均值的50%。频繁落叶处理的氮素产量在2004年从2.9增加到6gNm−2,2005年从1.2增加到2.8gNm−2。频繁的落叶显著降低了大叶参和羊草的总叶面积，但增加了它们的比叶面积。根系质量（0-15cm）在2004年平均为929gOMm−2,2005年为882gOMm−2，且物种组成不受频繁落叶的显著影响。结果表明，频繁的落叶对大叶参的生产力有积极的影响。年降水量基本上决定了该草地生态系统的生物量生产。在2个试验年里，由于频繁的落叶使群落的生产力有所提高，说明群落在短期内对落叶胁迫具有抵抗能力。
Grassland degradation due to over-grazing causes severe ecological and economical problems in the semi-arid grasslands of Inner Mongolia, PR China. The development of sustainable management systems is required, but basic information regarding the degradation process in its formation and development is rare. In 2004 and 2005 a cutting-frequency experiment was conducted in the Xilin River Basin, Inner Mongolia, subjecting a non-degraded grassland area to 3 different cutting frequencies: single defoliation at the end of growing season and defoliations every 6 and 3 weeks. It was hypothesised that the productivity of the S. grandis/L. chinensis community will be reduced by frequent defoliations. The cumulative dry matter yield increased with increasing defoliation frequency from 204 to 277gDMm−2in 2004 and from 87 to 158gDMm−2in 2005. The low aboveground biomass productivity in 2005 resulted from the low amount of precipitation, which was only 50% of the long-term mean. The nitrogen yield increased from 2.9 to 6gNm−2in the frequently defoliated treatments in 2004 and from 1.2 to 2.8gNm−2in 2005. Total leaf area was significantly reduced by frequent defoliation, but specific leaf area increased both in S. grandis and L. chinensis. Root mass (0–15cm) was on average 929gOMm−2in 2004 and 882gOMm−2in 2005 and, as well as species composition, not significantly influenced by frequent defoliations. It was concluded that frequent defoliation positively affected the productivity of the S. grandis/L. chinensis community, and that the annual amount of precipitation essentially determined the biomass production of this grassland ecosystem. Because the community increased its productivity after frequent defoliation in the 2 experimental years, it was suggested that the community is resistant to defoliation stress in the short-term.