Collaborative Research: Disrupted Nitrogen Cycles in the Brazilian Amazon

合作研究：巴西亚马逊地区氮循环中断

• 批准号: 1257391
• 负责人: Christopher Neill
• 金额: $ 49.35万
• 依托单位: Marine Biological Laboratory
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-10-01 至 2016-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1257391&HistoricalAwards=false
• 关键词: Collaborative; Research; Disrupted; Nitrogen; Cycles

Funds are provided to study nitrogen (N) cycles in the Brazilian Amazon. The research aims at quantifying N transformation and transport pathways in natural and agricultural settings in the Neotropics. The shift in agriculture combined with the increase in nitrogen fertilizer inputs in tropical regions have the potential to drive profound losses of nitrous oxide to the atmosphere, or increased movement of soluble N to rivers and streams. The proposed field research will quantify N2O fluxes and N fate in the vadose zone, groundwater and streams under natural conditions (tropical forest), single cropping of soybeans, and double cropping with soybeans and maize. Remote sensing will be used to scale up results from the field and model to the Amazon region, and incorporation of research results into a dynamic vegetation model (IBIS) that has been parameterized for the Amazon and will be used to estimate N emissions under different climate and land use management scenarios in the future. The work will test two hypotheses: (1) that increased N fertilization will lead to moderately but not greatly higher N2O emissions compared to natural forest because soils are well-drained and are not expected to go anaerobic long enough for accumulation of N2O, and (2) that N losses to streams will be minimal in N-fertilized plots because of high rates of uptake by maize crop and retention of any residual N leachates in deep, clay soils through anion exchange.The research will aid in understanding effects of changing agricultural practices on greenhouse gas emissions and stream pollution in the Amazon. Partnerships with local Brazilian scientists and training of US and Brazilian students will be important impacts from the research. Public outreach and broad dissemination of results will be achieved through regular presentations to agricultural producers and policy makers in Brazil through established contacts, as well as the support of a US journalist to visit the research field sites, which are locations of long-term ecological and biogeochemical research.

提供资金用于研究巴西亚马逊地区的氮 (N) 循环。该研究旨在量化新热带地区自然和农业环境中的氮转化和运输途径。农业的转变加上热带地区氮肥投入的增加，有可能导致一氧化二氮大量流失到大气中，或增加可溶性氮向河流和溪流的移动。拟议的实地研究将量化自然条件下（热带森林）、大豆单季以及大豆和玉米双季下包气带、地下水和溪流中的 N2O 通量和氮归宿。 遥感将用于将现场和模型的结果扩大到亚马逊地区，并将研究成果纳入动态植被模型（IBIS）中，该模型已针对亚马逊进行了参数化，并将用于估算未来不同气候和土地利用管理情景下的氮排放量。这项工作将检验两个假设：(1) 与天然林相比，增加施氮量将导致 N2O 排放量适度但不会大幅增加，因为土壤排水良好，预计厌氧时间不会长到足以积累 N2O；(2) 在施氮肥的地块中，溪流中的氮损失将降至最低，因为玉米作物的吸收率很高，并且任何残留的氮渗滤液都保留在深层， 该研究将有助于了解农业实践的改变对亚马逊地区温室气体排放和溪流污染的影响。与巴西当地科学家的合作以及对美国和巴西学生的培训将受到这项研究的重要影响。将通过已建立的联系定期向巴西农业生产者和政策制定者进行介绍，并支持一名美国记者参观研究现场，这些现场是长期生态和生物地球化学研究的地点，从而实现公众宣传和广泛传播成果。