Collaborative Research: Elucidating unifying principles of soil carbon-nitrogen coupling using a continental-scale grassland experimental network

合作研究：利用大陆尺度草地实验网络阐明土壤碳氮耦合的统一原理

• 批准号: 1556529
• 负责人: Sarah Hobbie
• 金额: $ 84.24万
• 依托单位: University of Minnesota-Twin Cities
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-06-15 至 2023-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1556529&HistoricalAwards=false
• 关键词: Collaborative; Research; Elucidating; unifying; principles

Human activities such as fertilizer use on crops, cultivation of soybean crops, and fossil fuel burning are increasing the amount of nitrogen gas that is circulating in the atmosphere and coming down in rain and snow in what is known as nitrogen deposition. The full impacts of high amounts of nitrogen deposition on ecosystems around the world are not well known. In particular, how nitrogen deposition alters the amounts and forms of carbon in soils is very poorly understood. Yet, achieving better understanding of this so-called coupling between the nitrogen and carbon cycles is important for life on earth. Plants and soils exchange large amounts of carbon dioxide with the atmosphere each year and so small changes in the rate of that exchange could affect how fast carbon dioxide in the air is rising. This project will integrate results from extensive cross-site, coordinated field experiments with modeling to improve our mechanistic understanding of the coupling of belowground carbon and nitrogen in grassland ecosystems. This is a key knowledge gap for Earth system models used to predict the biogeochemical consequences of human-caused global environmental changes and to refine predictions of carbon cycle feedbacks to climate change. This project will also connect researchers with education and outreach programs of the Cedar Creek Long-Term Ecological Research project. These programs are aimed at training K-12 students and teachers and increasing participation and retention of women and members of other underrepresented groups in science, with a special focus on mentoring undergraduate Native Americans in research. Project investigators will also mentor graduate students and post-doctoral scholars. This research will use a network of decade-long nutrient addition experiments in North American grasslands, the Nutrient Network, to study how enhanced nitrogen inputs influence soil microbial dynamics, soil carbon cycling, and the release of carbon dioxide to the atmosphere. Results will be used to enhance the Microbial ENzyme Decomposition (MEND) model towards determining how nitrogen inputs affect: (1) biochemical stabilization of soil organic matter (SOM) by altering the quantity and quality of plant inputs to soils, and soil microbial community structure, stoichiometry, and functional potential; and (2) physicochemical stabilization of SOM by altering soil aggregate formation and SOM-mineral interactions. Results of computer simulation models of ecosystem carbon and nitrogen cycling will be made available to the scientific community at large through the Accelerated Climate Model for Energy program at the Department of Energy. All data generated from the proposed work will also be made publically available through the Nutrient Network research project and the Long-Term Ecological Research network.

人类活动，例如在农作物上使用肥料，大豆农作物的种植和化石燃料燃烧等人的活动正在增加大气中循环的氮气量，并在雨天和雪中降低了氮气沉积。大量氮沉积对世界各地生态系统的全部影响尚不清楚。特别是，氮沉积如何改变土壤中碳的数量和形式。然而，对氮和碳周期之间的这种所谓的耦合，可以更好地理解对地球生命的重要性。植物和土壤每年将大量的二氧化碳交换为大气，因此该交换速率的较小变化可能会影响空气中二氧化碳的速度升高。该项目将将广泛的跨站点实地实验实验的结果与建模相结合，以提高我们对草地生态系统中地下碳和氮耦合的机械理解。这是用于预测人类引起的全球环境变化的生物地球化学后果的地球系统模型的关键知识差距，并完善对气候变化的碳循环反馈的预测。 该项目还将将研究人员与Cedar Creek长期生态研究项目的教育和外展计划联系起来。这些计划旨在培训K-12的学生和教师，并增加妇女的参与和保留，以及其他代表性不足的科学群体的成员，特别关注指导研究本科生研究的本科生。项目调查人员还将指导研究生和博士后学者。这项研究将在北美草原（养分网络）中使用长达十年的养分添加实验网络，以研究增强的氮输入如何影响土壤微生物动力学，土壤碳循环以及将二氧化碳释放到大气中。结果将用于增强微生物酶分解（MEND）模型，以确定氮输入如何影响：（1）通过改变土壤的植物投入的数量和质量，对土壤有机物的生化稳定（SOM），以及土壤微生物的社区结构，Stoichiemetry和Ontultiality; （2）通过改变土壤骨料的形成和Som-Mineral相互作用，对SOM的物理化学稳定。 生态系统碳和氮气循环的计算机模拟模型将通过能源部的能源计划加速气候模型提供给科学界的总体。从拟议工作中产生的所有数据也将通过营养网络研究项目和长期生态研究网络公开提供。