Collaborative Research: Ecosystem Significance of Soil as a Long Term Sink for Anthropogenic Additions of Nitrogen

摘要提案号：DEB-9707296， DEB-9708376研究者(S): BURKE JOHNSON机构：COLORADO STATE UNIVERSITY DESERT RESEARCH INSTITUTE， UNIVERSITY OF NEVADA尽管许多研究都集中在生态系统保留N的生物机制上，但对土壤中N的非生物固定（捕获）的关注相对较少。现有的证据表明，土壤能够将氮固定在腐殖质和粘土格等化学汇中，但对这种固定的控制知之甚少，化学固定的过程没有包括在主要的生物地球化学模型中。如果我们想要预测和理解全球大气氮沉降和肥料使用的增加对土壤的影响，那么填补这一认识上的空白是很重要的。本研究的目的是研究控制土壤中氮的长期积累，特别是通过非生物化学固定，并确定科罗拉多州草地土壤中非生物氮潴留增加的生态系统后果。该研究设计结合了含15-N化合物的实验添加，然后对化学转化进行复杂的化学分析。第二组实验包括向土壤中添加腐殖质前体。

ABSTRACT PROPOSAL # : DEB-9707296, DEB-9708376 INVESTIGATOR(S) : BURKE JOHNSON INSTITUTION: COLORADO STATE UNIVERSITY DESERT RESEARCH INSTITUTE, UNIVERSITY OF NEVADA Although much research has focused on the biotic mechanisms by which ecosystems retain N, there has been relatively little attention paid to nonbiological fixation (capture) of N in soils. The available evidence suggests that soils are capable of fixing N in chemical sinks such as humus and clay lattices but controls on this fixation are poorly understood and the processes of chemical fixation are not included in the leading biogeochemical models. It is important to fill this gap in our understanding if we are to be able to predict and understand effects on soils of global increases in both atmospheric N deposition and fertilizer use. The aims of this proposal are to investigate controls on the long-term accumulation of nitrogen in soils, particularly by nonbiological chemical fixation, and to determine the ecosystem consequences of increased nonbiological N retention in grassland soils in Colorado. The research design combines experimental addition of 15-N containing compounds, followed by sophisticated chemical analysis of chemical transformations. A second series of experiments involves addition of humus precursors to the soil.