Nitrogen budget in South America: observation and modeling

Jean Pierre Ometto1; Nnet Project team2

1National Institute for Space Research (INPE)

Av dos Astronautas, 1758

12227-010 – São José dos Campos, SP, Brazil



This paper, mirrored in the project report, presents a regional initiative, in South America, which aims to synthesize scientific information, acquire new data and informing the policy processes on the nitrogen budget and nutrient management in a broad region. The goal of this network is to examine human impact in natural and modified ecosystems across a wide range of climates, and ranging from direct measurements to regional modeling.  The up-scaling of local nitrogen studies aims to constrain regional atmospheric chemistry and transport modeling, feeding global models, greatly enhancing our understanding of global patterns of alterations to the nitrogen cycle. In the study sites, defined according to physiographic and/or socio-economic attributes, the following inputs and outputs of nitrogen are being reviewed and analyzed: (i) Inputs: Natural-BNF and cultivation induced-BNF, fertilizer use, atmospheric deposition;  (ii) Outputs: Net exports of agricultural products at regional level and estimates at site scale of gaseous emissions from land use (fertilizer volatilization, biogenic soil emissions and burning) and export of N to groundwater and surface waste (domestic, agricultural and industrial).

Canadian-US Project Towards an International Nitrogen Management System

Jill Baron1, Shabtai Bittman2, Robert Black3, Richard Sheibley3, Jana Compton4, Cliff Snyder5, Daniel Wise6

 1U.S. Geological Survey, Colorado State University, Fort Collins CO, 80523-1499,

2Agriculture and Agri-Food Canada, P.O. Box 1000, Agassiz, British Columbia, V0M 1A0

3U.S. Geological Survey, Washington Water Science Center, Tacoma WA 98402

4U.S. EPA Office of Research and Development, Corvallis OR 97333

5International Plant Nutrition Institute, Conway AR 72034

6U.S. Geological Survey, Oregon Water Science Center, Portland OR 97201


Bellingham Bay and the Nooksack River Basin will provide the test case for an international nitrogen (N) management system for North America. Spanning a portion of the western interface of the U.S. and Canada, the region supports intensive agriculture, freshwater and estuarine fisheries, diverse wildlife, cities and towns, and to the east, North Cascades National Park that is protected by the US Wilderness Acts. Using abundant data and model activities from a well-established scientific community, our project seeks to create knowledge, build regional capacity, and forge collaborations toward creation of regional N management solutions that protect or restore ecosystems and human health affected by excess reactive N while maintaining a vibrant agricultural community.

Nitroportugal – Strengthening Portuguese research and innovation capacities in the field of excess reactive nitrogen

Cláudia Marques-dos-Santos Cordovil1, Tommy Dalgaard2 and Mark A. Sutton3

1 Research Centre Linking Landscape, Environment, Agriculture and Food (LEAF), School of Agronomy, University of Lisbon, Tapada da Ajuda 1349-017 Lisbon, Portugal.

2 Department of Agroecology, Aarhus University, Blichers Allé 20, DK-8830 Tjele, Denmark.

3 NERC Centre for Ecology & Hydrology, Bush Estate, Penicuik Midlothian EH26 0QB Scotland, UK.


Nitrogen (N) is a key nutrient, indispensable for the survival of all living organisms on earth, including Man. However, due to human pressure, the N cycle has become the most altered among the element cycles, highlighting the N problem as one of the most pressing environmental issues faced today. Despite the recent work on N in Europe and the rest of the world, Portugal has not so far utilized its full capacity to integrate the available scientific, technical or practical knowledge. NitroPortugal addresses how to improve the Science and technology skills and the scientific output of Portugal, at the same time strengthening the potential for N policy implementation. The project develops around the consensus that N is an emerging issue, that it impacts all the environmental compartments, and has both human health and social implications. This twinning effort on N is divided into five key areas which coincide with the whole N concept WAGES (Water, Air, Greenhouse gases, Ecosystems and biodiversity and Soil) launched by the European Nitrogen Assessment. Based on bringing together existing data on data analysis and on training in new methods for each of the five key topics, a comprehensive analysis will be delivered that prioritizes the key gaps in knowledge. These gaps will then serve as themes for different types of training activities. Emerging questions will feed brainstorming workshops to be held at key points through the project, which will strengthen the Portuguese skills base and enhance peer-review publication. Based on the new skills of the host country team, the basis for preparing a Portuguese Nitrogen Assessment will be obtained that will strengthen Portuguese engagement within the EU and in UNECE Air and Water Conventions. The resulting increase in scientific productivity, associated with strengthened networking between the Portuguese and international partners will be measurable through objective indicators of publication output, policy support and the public engagement.

Reactive nitrogen releases and greenhouse gas emissions during the staple food production in China and their mitigation potential

Longlong Xia1, Xiaoyuan Yan 1*

1Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China,,


Reactive N (Nr) releases are closely linked with greenhouse gas (GHG) emissions, and the simultaneous evaluation of them can help to develop overall effective mitigation options. In this study, we evaluated the characteristics of the Nr and GHG releases from staple food (rice, flour and corn-based fodder) production in China (2001-2010) and explored their mitigation potential. Results showed that there was a high spatial variation in the Nr and carbon footprints. Provincial Nr footprints had a significant linear relationship with carbon footprints, attributed to large contribution of N fertilizer use to both GHG and Nr releases. NH3 volatilization and N leaching were the main contributors to the Nr footprints, while synthetic N fertilizer applications and CH4 emissions dominated the GHG (carbon) footprints. About 10 (95% uncertainty range: 7.4–12.4) Tg Nr-N and 564 (404–701) Tg CO2 eq GHG were released every year during 2001–2010 from staple food production in China. This caused the total damage costs of 325 (70–555) billion ¥, equivalent to nearly 1.44% of the Gross Domestic Product of China. A reduction of 92.7 Tg CO2 eq yr−1 and 2.2 Tg Nr-N yr−1 could be achieved by reducing synthetic N inputs by 20%, increasing grain yields by 5% and implementing off-season application of straw and mid-season drainage practices for rice cultivation.


How did chemical nitrogen efficiency evolve under agricultural intensification process in northern China from 1980 to 2014?

Xin Zhang1, Guangmin Xiao1, Roland Bol2, Wenliang Wu1, Fanqiao Meng1

1 College of Resources and Environmental Sciences, China Agricultural University, No. 2 Yuanming Xilu, Haidian, Beijing, 100193, China,

2 Institute of Bio- and Geosciences, Agrosphere (IBG–3), Research Centre Jülich, Jülich, 52425, Germany


During the past three decades of agricultural intensification in China, crop production has increased greatly. However, intensive agriculture is under pressure to reduce environmental pollution and improve nutrient use efficiency. We undertook a 35-year study in the Huantai county to analyse the temporal dynamics of N efficiency, losses and driving factors during this process. From 1982 to 2002, N partial factor productivity (PFPN) and N uptake efficiency (NUpE) increased 2.0-fold and 1.8-fold, and then stabilised from 2003 to present (PFPN at 36.4 kg grain kg-1 Nfert, and NUpE at 0.57 kg Nplant kg-1 Nfert+min). Similarly, decreases were observed in reactive N losses intensity (32.0 to 10.7 kg N Mg-1 grain), land intensity (0.13 to 0.06 ha Mg-1 grain) and N uses intensity (49.2 to 24.6 kg N Mg-1 grain), and then were stable from 2002 to 2014. Nitrogen utilization efficiency (NUtE) was stable at about 42 kg grain kg-1 Nplant during the 35 years. Apparent N use efficiency (ANUE) increased from 42.1% in the 1980s to 60% in 2010s. The increase of N use efficiency and decrease of N losses depended much on optimized fertilization, mechanization farming and crop straw incorporation. This highlighted that with the introduction of improved farming practices, a sustainable agricultural intensification was achieved in developing countries like China.

Towards a nitrogen budget for different forests types of the central Congo Basin

Marijn BAUTERS1,2, Hans VERBEECK2, Landry CIZUNGU3 and Pascal BOECKX1

1 Isotope Bioscience Laboratory – ISOFYS, Ghent University, Coupure Links 653, 9000 Gent, Belgium

2 CAVElab, Computational and Applied Vegetation Ecology, Department of Applied Ecology and Environmental Biology, Ghent University, Coupure Links 653, 9000 Gent, Belgium

3 Faculty of Agronomy, Université Catholique de Bukavu, Avenue de la mission, BP 285, Bukavu, DR Congo.

Ϯ E-mail:


Recent data analyses and modelling activities have shown that the CO2 uptake by terrestrial ecosystems strongly depends on site fertility, i.e. nutrient availability. Accurate projections of future net forest growth and terrestrial CO2 uptake thus necessitate an improved understanding on nutrient cycles and how these are coupled to the carbon cycle. This holds especially for tropical forests, since they represent about 40–50% of the total carbon that is stored in terrestrial vegetation. Central African forests are very poorly characterized and their role in global change interactions shows distinct knowledge gaps. Research in the Congo Basin region should combine assessments of both carbon stocks and the underlying nutrient cycles, which directly impact the forest productivity. We set up a monitoring network for carbon stocks and nitrogen fluxes in different forest types in the Congo Basin, which is now operative. Preliminary data show an atmospheric N deposition of 20-30 kg N ha-1 yr-1 with N mainly derived from fires and different N dynamics in mixed vs. mono-dominant forests, whereby the N economy of ectomycorrhizal fungi is likely the driving force for establishment mono-dominant forest ecosystems and nitrate leaching.

Relative contributions of NH3, NO2, NH4+ and NO3- to total Nitrogen deposition at an agricultural site in the Indo-Gangetic Plain of India

Saumya Singh*, Anshu Sharma* and U.C. Kulshrestha*

*School of Environmental Sciences, Jawaharlal Nehru University, New Delhi 110067 INDIA


Atmospheric emissions of reactive nitrogen (Nr) species namely NH3 and NOx are at high levels in India in recent years, but only a few studies have employed nitrogen (N) deposition monitoring for gaseous and particulate N depositions together to evaluate total dry N deposition.  In the present study, gaseous N pollutants (NH3 and NO2) and related ionic species (NH4+, NO3) were determined in water-soluble fine particulates at an agricultural site in the Indo-Gangetic Plain (IGP) during July-Sept,2013 with the aim of estimate the relative contribution of respective species to total dry N deposition. The NH3 and NO2 levels were recorded as 30.41µg/m3 and 4.0 ±2.3 µg/m3. Aerosol NH4+ and NO3concentrations were measured at 0.37 µg/m3 and 1.43 µg/m3.These values are at a relatively higher scale which might be due to high fertilizer use and biomass burning. Contribution of reduced for and oxidized form of nitrogen was also calculated.

The Increasing Importance of U.S. Reduced Nitrogen Deposition

Jeffrey L. Collett, Jr.1, Yi Li1, Bret A. Schichtel2, John T. Walker3, Donna B. Schwede3, Xi Chen3, Christopher M.B. Lehmann4, Melissa A. Puchalski5, and David A. Gay4

1Department of Atmospheric Science, Colorado State University, Fort Collins, Colorado, USA,
2National Park Service, Cooperative Institute for Research in the Atmosphere, Colorado State University, Fort Collins, Colorado, USA
3U.S. Environmental Protection Agency, Office of Research and Development, Research Triangle Park, North Carolina, USA
4National Atmospheric Deposition Program, University of Illinois Urbana-Champaign, Champaign, Illinois, USA
5U.S. Environmental Protection Agency, Clean Air Markets Division, Washington D.C., USA.


U.S. reactive nitrogen emissions increased greatly in the last century due to rapid increases in fossil fuel combustion and development of agriculture.  One result was excess nitrogen deposition to many natural ecosystems. Successful policies in the last two decades to reduce nitrogen oxides emissions have substantially decreased nitrate wet deposition. Levels of wet ammonium deposition, however, have increased in many regions. Overall, the balance between oxidized and reduced nitrogen deposition has shifted from a nitrate-dominated situation in the 1980s to an ammonium-dominated situation today. Although gaseous ammonia has not historically been routinely measured in the U.S., a recent expansion in observations, combined with ongoing measurements of nitric acid and fine particle ammonium and nitrate, provides new insight into the balance of oxidized and reduced nitrogen in the total (wet + dry) U.S. nitrogen deposition budget. Observations reveal that reduced nitrogen contributes approximately 65 percent, on average, of the total inorganic nitrogen deposition budget. Dry deposition of ammonia plays an especially key role in nitrogen deposition.  While U.S. emissions of nitrogen oxides are expected to continue to decline in the foreseeable future, ammonia emissions are projected to grow.  Continued progress toward reducing U.S. nitrogen deposition will be increasingly difficult without new efforts to reduce ammonia emissions.

Nitrogen Emission and Deposition Budget in Africa

Galy-Lacaux1, C. Delon1, K. Pienaar2, M. Adon1,3, V. Yoboué3, B. Diop4, L. Sigha5, D. Laouali6, A. Akpo7

1 Laboratoire d’Aérologie, Université de Toulouse, CNRS, Toulouse, France,

2 School of Physical and Chemical Sciences, North-West University, Potchefstroom, South Africa

3 Université de Cocody, Abidjan, Côte d’Ivoire

4 Université de Bamako, Mali

5 Université de Yaoundé CRH IRGM, Yaoundé, Cameroun

6 Université de Niamey, Niger

7 Université Abomey Calavi, Cotonou, Benin


Atmospheric nitrogen concentrations depend on land surface exchanges of nitrogen compounds. In Africa, deposition and emission fluxes of nitrogen compounds are poorly quantified, and are likely to increase in the near future due to land use change and anthropogenic pressure. This work is part of the long term deposition monitoring project IDAF initiated in the 1990s. IDAF (IGAC/DEBITS/Africa) is the African contribution to study deposition in the IGAC/DEBITS programme and contributes to the WMO-GAW programme. This work proposes an estimate of an atmospheric N compounds budget in Africa, along an ecosystem transect, from dry savanna to wet savanna and forest, for the years 2000 to 2007. The budget takes into account: (1) gaseous dry deposition fluxes estimated by considering N compounds concentrations at the monthly scale and modeling of deposition velocities at the IDAF sites, (2) wet deposition fluxes calculated from measurements of ammonium and nitrate chemical content in precipitations and (3) N emission sources taking into account simulated NO biogenic emission from soils, NH3 emission by volatilization and NOx and NH3 emission from biomass burning and domestic fires. This regional N emission deposition budget should give the present status at the scale of the main African ecosystems and should help to quantify the processes that may contribute to the changing levels of N deposition.

Assessment of current and critical nitrogen inputs on European agricultural soils

Wim de Vries1,2, Johannes Kros2

1 Alterra Wageningen University and Research Centre, PO Box 47, 6700 AA Wageningen, the Netherlands,,

2 Environmental Systems Analysis Group, Wageningen University, PO Box 47, 6700 AA Wageningen, the Netherlands.


The intensification of  European agriculture, including large inputs of nitrogen (N) to soil by fertilizers and manure, has led to an increase in crop growth but also in various adverse effects. This includes: (i) loss of biodiversity in natural terrestrial ecosystems due to increased emission and deposition of ammonia (NH3), (ii) eutrophication of surface waters due to increased N runoff and (iii) increased nitrate (NO3) levels in drinking water reservoirs due to elevated N leaching. In this study we identified agricultural regions where current N inputs exceed critical N inputs at a high spatial resolution for the entire European Union using the INTEGRATOR model. Critical N inputs were derived on the basis of critical N losses, which in turn were based on critical levels of NH3 emission and critical N concentrations in leaching to ground water or runoff to surface water in view of the adverse impacts listed above. Results show that at EU-27 level, current N inputs slightly exceed critical N inputs in view of eutrophication by 15% for aquatic ecosystems and 25% for terrestrial ecosystems. We identified those places where there is a need to lower N losses to acceptable levels by increasing the nitrogen use efficiency (NUE).