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不同干扰类型对滇西北亚高山草甸植物化学计量特征的影响

Effects of Different Disturbance Types on Plant Stoichiometric Characteristics in Subalpine Meadows of Northwest Yunnan

  • 摘要: 以云南迪庆亚高山草甸为研究对象,设置放牧、封育、封育 + 火烧、封育 + 施肥、封育 + 火烧 + 施肥5种处理,分析其对草地植物群落碳(C)、氮(N)、磷(P)、钾(K)生态化学计量特征的调控效应。结果表明:干扰方式显著影响植物C、N、P、K养分含量及计量关系。其中封育 + 施肥处理植物C、N含量最高;封育 + 火烧 + 施肥处理可提升C、N、P含量,且P含量增加最为显著;放牧处理显著降低了C、N、P含量,但提高了K含量;封育 + 火烧处理降低了植物群落C、N、P、K含量,表明放牧和封育 + 火烧导致植物营养流失。研究区域植物N:P(21.9)和C:P(369.96)均高于中国草地生态系统平均水平,表明植物生长主要受P限制。相关性分析表明,植物C与N呈极显著正相关,表现为协同积累;C、N与K呈显著负相关,显示C、N同化与K吸收间存在拮抗关系。综上,干扰措施可显著调控植物养分积累与限制格局,封育 + 施肥处理有利于促进植物C、N固持,而封育 + 火烧 + 施肥处理则可协同提高植物C、N、P含量,有效缓解P限制,是适用于当地亚高山草甸恢复及放牧管理的可行措施。

     

    Abstract: To clarify the effects of different disturbance regimes on plant nutrient balance and limitation characteristics in subalpine meadows, this study took the subalpine meadows in Diqing Prefecture, Yunnan Province as the research object, and analyzed the regulatory effects of five disturbance regimes (grazing, fencing, fencing + burning, fencing + fertilization, and fencing + burning + fertilization) on the ecological stoichiometric characteristics and stoichiometric ratios of carbon (C), nitrogen (N), phosphorus (P), and potassium (K) in grassland plant communities. The results showed that disturbance regimes significantly altered plant nutrient contents (C, N, P, K) and their stoichiometric relationships. The enclosure + fertilization treatment yielded the highest C and N contents. The enclosure + fire + fertilization treatment also increased C, N, and P contents, with the most pronounced increase observed for P. The grazing treatment decreased C, N, and P contents but increased K content. The enclosure + fire treatment reduced all measured plant nutrient contents (C, N, P, K), indicating nutrient loss under both grazing and enclosure with fire. Stoichiometric ratio analysis revealed that the N:P ratio (21.9) and C:P ratio (369.96) of plants in the study area were both higher than the average levels of grassland ecosystems in China, indicating that plant growth is primarily limited by P.Correlation analysis further indicated a highly significant positive correlation between plant C and N, reflecting synergistic accumulation. In contrast, C and N were significantly negatively correlated with K, indicating an antagonistic relationship between the assimilation of C and N and the uptake of K. In summary, disturbance measures significantly regulated plant nutrient accumulation and limitation patterns.Enclosure + fertilization is beneficial for promoting C and N retention in plants, whereas enclosure + fire + fertilization can synergistically enhance C, N, and P contents, effectively alleviating P limitation. These integrated measures represent viable strategies for the restoration and grazing management of local subalpine meadows.

     

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