Plant mixtures can enhance soil quality and optimize ecosystem carbon (C), nitrogen (N), and phosphorus (P) (C:N:P) stoichiometry to support sustainable production; yet this hypothesis has not been thoroughly examined in mixed plantations containing N-fixing tree species (N-fixers). Introduced N-fixers are often used as alternatives to N fertilization in forest plantations but may potentially disrupt the ecosystem C:N:P stoichiometric balance. Here, we compared the effects of N fertilization (100 kg N ha year) and the introduction of an N-fixer () into plantations on the C:N:P stoichiometry across soil, microorganisms, enzymes, and leaves and roots. The experiment was organized into a randomized complete block design (n = 5) and lasted five years. N fertilization generally caused an imbalance in ecosystem C:N:P stoichiometry except for the microbial biomass C:N ratio. Introduced the N-fixers decreased the soil C:N ratio and increased the C:P and N:P ratios, whereas the other pools of C:N:P stoichiometry remained unchanged. Two meta-analyses further verified these findings, reinforcing the idea that mixed plantations with N-fixers, as a substitute for N fertilization, can help maintain ecosystem C:N:P stoichiometry to support sustainable production. Comparing the effects of N fertilization and introduced N-fixers using structural equation modeling approach underscored the importance of plant-microbial interactions in maintaining the balance of ecosystem C:N:P stoichiometry. This, in turn, can provide government and policymakers with compelling evidence for a nature-based solution for sustainable plantation management.

中文翻译：

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具有固氮树种的混合种植园维持生态系统 C:N:P 化学计量：对可持续生产的影响

植物混合物可以提高土壤质量并优化生态系统碳（C）、氮（N）和磷（P）（C:N:P）化学计量，以支持可持续生产；然而，这一假设尚未在含有固氮树种（固氮树种）的混合种植园中得到彻底检验。引入的固氮剂通常用作人工林中氮肥的替代品，但可能会破坏生态系统的 C:N:P 化学计量平衡。在这里，我们比较了施氮肥（每年 100 公斤氮）和在种植园中引入固氮剂 () 对土壤、微生物、酶以及叶子和根的 C:N:P 化学计量的影响。该实验采用随机完整区组设计（n = 5），持续五年。除微生物生物量 C:N 比率外，施氮肥通常会导致生态系统 C:N:P 化学计量失衡。引入固氮剂降低了土壤 C:N 比率并增加了 C:P 和 N:P 比率，而其他池的 C:N:P 化学计量保持不变。两项荟萃分析进一步验证了这些发现，强化了这样的观点：使用固氮剂的混合种植园作为氮肥的替代品，可以帮助维持生态系统的 C:N:P 化学计量，以支持可持续生产。使用结构方程建模方法比较施氮肥和引入固氮剂的效果，强调了植物-微生物相互作用在维持生态系统 C:N:P 化学计量平衡中的重要性。反过来，这可以为政府和政策制定者提供基于自然的可持续种植园管理解决方案的令人信服的证据。