U.S.-Hungary Research on a Cross-Continental Study of Controls on Soil Carbon and Nitrogen Dynamics

这个美国-匈牙利研究项目包括在美国的三个既定地点和匈牙利的一个地点对土壤有机质形成的控制或“碎屑输入和去除处理”（DIRT）进行长期研究。俄勒冈州立大学的Kate Lajtha与匈牙利德布勒森科苏斯大学的Janos atila Toth合作，担任美国首席研究员。DIRT的目标是评估植物凋落物输入的速率和来源如何在年代际时间尺度上控制森林土壤中有机质和养分的积累和动态。这个由美国和匈牙利组成的研究小组打算研究土壤中多个层次的过程，以探索导致腐殖质物质长期形成的化学和生物相互联系。特别令人感兴趣的是土壤有机碳(C)以及无机和有机氮(N)的稳定和保持，因为土壤有机质分解过程似乎影响全球碳固存。匈牙利Sikfokut长期生态研究站点通过该项目加入了美国的努力，该站点位于匈牙利埃格尔的温带落叶栎林。它将欧洲的一个地点带到了这个项目中，那里的植被与美国东部的森林地点相似，但却显示出明显更高的氮输入。因此，与匈牙利同行在Sikfokut的合作研究提供了一个独特的机会，可以在一个结构相似的系统中测试假设，该系统具有极端的N输入和森林地面化学。计划中的合作有三个重点：a)对氮动力学和淋失控制的分析；B)碳形成、稳定、不稳定相互作用机制的动力学分析；c)田间土壤呼吸测量。研究结果有望在大的气候和污染历史梯度中揭示氮和碳的封存和损失途径。这项跨大陆的土壤动力学研究实现了推进科学知识的计划目标，使美国和中欧的专家能够结合互补的人才，并在共同感兴趣和有能力的领域分享研究资源。

INT 0002956LajthaThis U.S.-Hungary research project involves a long-term study of controls on soil organic matter formation or "Detritus Input and Removal Treatments" (DIRT) at three established sites in the United States and one in Hungary. Kate Lajtha of Oregon State University serves as the U.S. principal investigator in cooperation with her Hungarian counterpart, Janos Atilla Toth of Kossuth University in Debrecen. The goal of DIRT is to assess how rates and sources of plant litter inputs control the accumulation and dynamics of organic matter and nutrients in forest soils over decadnal time scales. The U.S.-Hungarian research team intends to examine processes at multiple levels in the soil to explore the chemical and biological interconnections that lead to formation of humic materials over long time spans. Of special interest is the stabilization and retention of soil organic carbon (C) and inorganic and organic nitrogen (N) because soil organic matter decomposition processes appear to influence global carbon sequestration.The Hungarian Sikfokut long-term ecological research site that joins the U.S.-based effort via this project is a temperate deciduous oak forest located in Eger, Hungary. It brings a European site to the effort that has vegetation similar to participating eastern U.S. forest sites, yet one that exhibits significantly higher nitrogen inputs. Thus, cooperative research with Hungarian counterparts at Sikfokut offers a unique opportunity to test hypotheses in a structurally similar system with extreme N input and forest floor chemistry. The planned collaboration has three foci: a) an analysis of the controls on N dynamics and leaching; b) analysis of carbon dynamics due to interacting mechanisms of formation, stabilization, destabilization; and c) field soil respiration measurements. Results are expected to shed new light on the pathways of N and C sequestration and loss, across a large climatic and pollution history gradient.This cross-continental study of soil dynamics fulfills the program objectives of advancing scientific knowledge by enabling experts in the United States and Central Europe to combine complementary talents and share research resources in areas of strong mutual interest and competence.