Research Starter Grant: The Role of Soil Nitrogen in Plant Litter Decomposition

土壤氮(N)有效性通过两种方式控制植物凋落物的分解。首先，它通过影响植物生长和分配来影响凋落物的质量或相对可分解性。其次，土壤氮有效性可能直接限制分解者的活动。由于凋落物的碳(C)氮比通常高于细菌和真菌，这些分解者必须从土壤溶液中固定N，以便利用凋落物中的C进行代谢活动和生长。本研究的目的是利用一种测量分解过程中总氮固定和损失的新方法，对土壤有效氮和植物凋落物质量之间的相互作用如何影响分解进行机制理解。这项研究还将提供有关火灾对北方森林分解的影响的信息。了解火灾如何改变分解是理解生态系统C平衡如何随着与人为驱动的气候变化相关的火灾频率和强度的增加而变化的关键。最后，本研究的机械方法应使其发现普遍适用于理解其他系统中对分解的控制。

Soil nitrogen (N) availability controls the decomposition of plant litter in two ways.First, it affects the quality or relative decomposability of litter through effects on plant growth and allocation. Second, soil N availability may directly limit the activity of decomposers. Because the Carbon (C) to N ratio of litter is usually higher than that of bacteria and fungi, these decomposers must immobilize N from the soil solution in order to use C in plant litter for metabolic activity and growth. The objective of this study is to develop a mechanistic understanding of how interactions between soil available N and plant litter quality affect decomposition using a novel method for measuring total N immobilization and loss during decomposition. This study will also provide information about the effects of fire on decomposition in boreal forest. Understanding how decomposition is altered by fire is key to understanding how ecosystem C balance may change with the increased fire frequency and intensity that is associated with anthropogenically-driven climate change. Finally, the mechanistic approach of this research should be make its findings generally applicable to understanding controls over decomposition in other systems.