Forest residues from Eucalyptus plantations, including the belowground biomass, has become an important energy source in tropical countries. However, the belowground biomass harvesting may reduce wood productivity in the subsequent rotations due to the depletion of soil nutrients. Thus, the present study aimed to evaluate the nutritional sustainability of Eucalyptus clones’ plantations grown on second rotation in different above and belowground biomass harvest scenarios. Second rotation clones were used: Eucalyptus urophylla (AEC 0144); Eucalyptus urophylla × E. grandis (H77); and Eucalyptus urophylla × E. camaldulensis (VM01) at 13.1, 12.9 and 12.0 years of age, respectively. Trees were uprooted and split into leaves, branches, bark, stemwood and belowground. Biomass production, concentration, stock, export and use efficiency of N, P, K, Ca, Mg, B, Cu, Fe, Mn and Zn were evaluated. The highest belowground biomass production occurred in the VM01 clone, while AEC 0144 clone had the highest production of stemwood biomass. Stemwood and belowground biomass fractions had the lowest nutrient concentrations. The highest concentrations of nutrients were verified in leaves, branches and bark. Stemwood and stemwood with belowground biomass harvest scenarios presented the lowest nutrient export values and highest NUE values. Our results demonstrate that woody production of belowground biomass represents a significant part of the total biomass production of Eucalyptus trees. Thus, the removal of leaves, branches and bark fractions is more harmful to the nutritional sustainability of sandy soils than the harvesting of stumps in second rotation plantations.

桉树种植园的森林残留物，包括地下生物质，已成为热带国家的重要能源。然而，由于土壤养分的消耗，地下生物质收获可能会降低随后轮作中的木材生产力。因此，本研究旨在评估桉树无性系种植园在不同的地上和地下生物量收获情景中第二轮种植的营养可持续性。使用了第二轮克隆：Eucalyptus urophylla (AEC 0144)；Eucalyptus urophylla  ×  E. grandis (H77)；和Eucalyptus urophylla  ×  E. camaldulensis(VM01) 分别为 13.1、12.9 和 12.0 岁。树木被连根拔起，分裂成树叶、树枝、树皮、茎木和地下。对 N、P、K、Ca、Mg、B、Cu、Fe、Mn 和 Zn 的生物质生产、浓度、库存、输出和利用效率进行了评估。VM01 克隆的地下生物量产量最高，而 AEC 0144 克隆的茎木生物量产量最高。茎木和地下生物量部分具有最低的养分浓度。在叶子、树枝和树皮中验证了最高浓度的营养物质。茎木和具有地下生物量的茎木收获情景呈现最低的养分输出值和最高的 NUE 值。我们的研究结果表明，地下生物量的木本生产占桉树总生物量生产的重要部分。因此，与在第二轮种植园中收获树桩相比，去除叶子、树枝和树皮部分对沙质土壤的营养可持续性更有害。