Does synergy among litter, organic horizons, and roots bolster nutrient retention and production?

温带森林正受到来自土地管理变化、大气污染和气候变化的越来越大的环境压力。这些环境变化对温带森林土壤中无机养分（镁、磷、钾、钙）的储存和循环有重要影响。无机营养素是植物生长所必需的，来源于土壤中的矿物风化、大气沉积和植物落叶。虽然根以其为植物提取无机营养素的作用而闻名，但它们可以贡献有机物质，以帮助将无机营养素储存在土壤中。本研究项目探讨落叶和地表根系如何促进土壤中无机养分的储存及其相互依赖的程度。为了了解气候对落叶和根系无机养分循环的控制，研究人员将利用从弗吉尼亚州暖温带森林到北方新英格兰冷温带森林的研究地点网络。这些发现将用于向美国林务局和几个州的林业和自然资源部门通报其森林中当前和未来的无机养分循环。此外，位于马萨诸塞州的研究中心将作为大学和社区学院课程的教学工具。该项目的主要目标是量化的相互依赖的落叶和根镁，磷，钾，钙稳定在温带森林土壤。枯落物和根系可能通过产生有机质和团聚体协同作用，稳定矿质土壤中的无机养分。为了避免土壤材料的异质性和开发时间的共同问题，该项目将利用三年前埋下的土柱，含有石英-长石-高岭石混合物，以研究落叶和树根对矿物土壤中无机养分的影响。研究人员将量化散装土壤中无机养分稳定化的速率，并使用微探针分析来检查根际和微聚集。此外，该项目将利用现有的凋落物和大气沉积监测来估计养分循环预算。当在整个气候梯度上进行检查时，研究结果可用于预测未来营养循环的变化，从叶枯落物-根相互依赖性的变化与气候的变化。该奖项反映了NSF的法定使命，并被认为值得通过使用基金会的知识价值和更广泛的影响审查标准进行评估来支持。

Temperate forests are under increasing environmental stresses from changes in land management, atmospheric pollution, and a changing climate. These environmental changes have important effects on how inorganic nutrients (Magnesium, Phosphorus, Potassium, Calcium) are stored and cycled in the soils of temperate forests. Inorganic nutrients are essential for plant growth and are sourced to soils from mineral weathering, deposition from the atmosphere, and leaf litter from plants. While roots are known for their role in extracting inorganic nutrients for plants, they can contribute organic matter to help store inorganic nutrients in soils. This research project explores how leaf litter and surface roots promote inorganic nutrient storage in soils and the extent of their codependence. To understand climatic controls on leaf litter and roots for inorganic nutrient cycling, the researchers will leverage a network of research sites spanning from the warm temperate forests of Virginia to the cold temperate forests of northern New England. The findings will be used to inform the U.S. Forest Service and several state Forestry and Natural Resources Departments of the current and future inorganic nutrient cycling in their forests. Furthermore, the research site in Massachusetts will serve as an instructional tool for university and community college courses. The primary objective of the project is to quantify the codependence of leaf litter and roots on Mg, P, K, and Ca stabilization in temperate forest soil. Leaf litter and roots may act synergistically to stabilize inorganic nutrients in the mineral soil through generating organic matter and aggregation. To avoid the common issue of heterogeneity of soil materials and duration of development, the project will leverage soil columns buried three years ago, containing a quartz-feldspar-kaolinite mixture to examine the effect of leaf litter and tree roots on inorganic nutrients in mineral soil. Researchers will quantify the rate of inorganic nutrient stabilization in bulk soils and use microprobe analyses to examine rhizosphere and microaggregation. Moreover, the project will utilize existing litterfall and atmospheric deposition monitoring to estimate nutrient cycling budgets. When examined across the climate gradient, the findings can be used to predict future shifts in nutrient cycling from shifts in leaf litter-root codependence with changes in climate.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.