Litter production and decomposition are critical to forest productivity, nutrient cycling, and carbon sequestration in tropical woody ecosystems. However, nutrient release and leaf litter stoichiometry in tropical legume tree plantations over the long term after outplanting are poorly understood or even unknown. Toward improving our understanding of the pattern of changes in the decomposition of N-fixing leaf litters and their possible impact on carbon storage, we measured litter production, mass loss and nutrient release for 240 d during litter decomposition for two tropical legume tree species (Plathymenia reticulata and Hymenaea courbaril), in Rio de Janeiro, Brazil. Litter production for P. reticulata was 5.689 kg ha⁻¹ a⁻¹ and 3.231 kg ha⁻¹ a⁻¹ for H. courbaril. The patterns of mass loss rates were similar; however, nutrient release was greater for P. reticulata, while H. courbaril showed immobilization of nutrients, especially for N, which increased by almost 20% in the early phase of decomposition followed by gradual release. Litter from the N-fixing species did differ in nutrient chemistries over time, which was not surprising given that initial nutrient concentrations varied broadly, except for C and P. Most of the nutrient concentrations increased as the remaining litter mass decreased in both species, except for C and K. The C:N and N:P ratios differed between the species, but N:P did not correlate to mass loss. Both species had N-rich leaves, but P. reticulata decomposition was very likely P-limited, while H. courbaril seemed to be co-limited by N and P. The results showed different patterns in nutrient release and the stoichiometry involved in the decomposition dynamics of the two tropical N-fixing species, even though they have similar litter decay rates. Both species, but especially P. reticulata, may help re-establish nutrient cycling in disturbed ecosystems.

凋落物的产生和分解对热带木质生态系统中的森林生产力、养分循环和碳固存至关重要。然而，外植后热带豆科植物种植园的长期养分释放和落叶化学计量学知之甚少，甚至未知。为了加深我们对固氮凋落叶分解变化模式及其对碳储存可能产生的影响的理解，我们测量了两种热带豆科植物（Plathymenia reticulata和Hymenaea courbaril），在巴西里约热内卢。P. reticulata 的凋落物产量为5.689 kg ha ^-1  a^-1和3.231公斤公顷^-1 一^-1为H.苏木。质量损失率的模式相似；然而，P. reticulata 的养分释放更大，而H. courbaril显示养分固定，尤其是 N，在分解的早期阶段增加了近 20%，然后逐渐释放。随着时间的推移，固氮物种的凋落物在营养化学方面确实不同，这并不奇怪，因为除了 C 和 P 之外，初始营养浓度变化很大。随着剩余凋落物质量的减少，大多数营养浓度增加，除了对于 C 和 K。C:N 和 N:P 比率在物种之间有所不同，但 N:P 与质量损失无关。两个物种都有富含 N 的叶子，但P. reticulata分解很可能受 P 限制，而H. courbaril似乎受到 N 和 P 的共同限制。结果显示两种热带固氮物种的分解动力学所涉及的养分释放模式和化学计量不同，即使它们具有相似的凋落物衰减率。这两种物种，尤其是P. reticulata，可能有助于在受干扰的生态系统中重建营养循环。