Vegetation C–N–P accumulation and allocation patterns at the community level in early restored plantations in the loess hilly-gully region

Abstract

Accumulation of vegetation biomass is a crucial process for carbon fixation in the early stage of afforestation and a primary driving force for subsequent ecological functions. Accurately assessing the storage and allocation of elements in plantations is essential for their management and estimating carbon sink capacity. However, current knowledge of the storage and allocation patterns of elements within plant organs at the community level is limited. To clarify the distribution patterns of elements in plant organs at the community level, we measured the biomass within plant organs of five typical plantations in the early stage of afforestation in the loess hilly-gully region. We assessed the main drivers of element accumulation and distribution by employing redundancy analysis and random forest. Results revealed significant differences in biomass storages among plantations and a significant effect of plantation type on the storages of elements within plant organs. Furthermore, the dominant factors influencing C–N–P storage and allocation at the community level were found to be inconsistent. While the storage of elements was mainly influenced by stand openness, total soil nitrogen, and plant diversity, the allocation of elements in organs was mainly influenced by stand openness and soil water content. Overall, the spatial structure of the community had an important influence on both element storage and allocation, but soil conditions played a more important role in element allocation than in storage. Random forest results showed that at the community level, factors influencing element storage and allocation within plant organs often differed. The regulation of elemental storage could be regulated by the major growth demand resources, while the allocation was regulated by other limiting class factors, which often differed from those that had a significant effect on element storage. The differences in plant organ elemental storage and allocation drivers at the community level reflect community adaptation strategies and the regulation of resources by ecosystems in combination with plants. Our study provides valuable insights for enhancing plantation C sink estimates and serves as a reference for regulating element storage and allocation at the local scale.

Keywords

• Afforestation
• Plant organ
• Biomass accumulation
• Element allocation