Regional nitrate deposition inferred from ground- and space-based measurements

Miaomiao CHENG1, Zheng GUO2, Fan MENG1

1 State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China,

2 Division of Remote Sensing Data Application, National Satellite Meteorological Centre, Beijing 100081, China


Spatial and temporal nitrate deposition fluxes were assessed using satellite data in the Yangtze River Delta (YRD) from 1996 to 2011. Our study reveals significant spatial variations of nitrate deposition. In general, the fluxes of total (dry plus wet) nitrate deposition was up to 22 kg N ha-1 yr-1 with large loading rates received in winter. Most high fluxes appeared over urban (38 kg N ha-1 yr-1) and cropland (30 kg N ha-1 yr-1) areas. During the study period (1996-2011), a significant increasing trend of nitrate deposition was observed with an annual increasing rate of 1.33 kg N ha-1 yr-1. The spatial patterns of estimated nitrate deposition also showed that there were much higher fluxes and annual increasing trend in the middle region of YRD, i.e., the metropolitan areas contained Shanghai-Nanjing-Hangzhou cities, than in other areas. Our results also reveal that dry nitrate deposition contributed more than 50% of the total nitrate deposition over all provinces and land covers except coastal sea (14%), which indicates the relative importance of dry deposition to the total nitrate deposition in YRD region. Our study suggests that it is necessary to consider both dry and wet deposition when evaluating the influences of nitrate deposition on environment and ecosystem health.

Atmospheric nitrogen deposition in a subtropical hydroelectric reservoir (Nam Theun II case study, Lao PDR)

Adon1, C. Galy-Lacaux2, D. Serça2, F. Guerin3, P. Guedant4, A. Vonghamsao4, W. Rode4.

1 Laboratoire de Physique de l’Atmosphère et de Mécanique des Fluides, Université Félix Houphouët-Boigny, Abidjan, Côte d’Ivoire, E-mail :

2 Laboratoire d’Aérologie, Université de Toulouse, CNRS, UPS, France

3 GET (Geosciences Environnement Toulouse), UMR 5563, Toulouse, France

4 Nam Theun 2 Power Company Limited (NTPC), Environment & Social Division – Water Quality and Biodiversity Dept. – Gnommalath Office, P.O. Box 5862, Vientiane, Lao PDR


This study presents an estimation of the atmospheric inorganic nitrogen deposition into the NT2 hydroelectric reservoir, in the subtropical region of the Lao PDR, based on a two-year monitoring (June 2010 to July 2012) including gas concentrations and precipitation. Dry deposition fluxes are calculated from monthly mean surface measurements of NH3, HNO3 and NO2 concentrations (passive samplers) together with simulated deposition velocities. Wet deposition fluxes are calculated from NH4+ and NO3 concentrations determined in single event rain samples (automated rain sampler). Annual rainfall depth was 2502 mm and 3162 mm in 2010 and 2011, respectively. The average nitrogen deposition flux is estimated at 1.26 kg N ha-1 yr-1 from dry processes and 5.01 kg N ha-1 yr-1 from wet ones, i.e., an average annual total nitrogen flux of 6.3 kg N ha-1 yr-1 deposited into the NT2 reservoir with 80% from wet deposition.

Human nitrogen fixation and greenhouse gas emissions: a global assessment

Wim de Vries1,2, Enzai Du3, Klaus Butterbach-Bahl4, Lena Schulte-Uebbing2, Frank Dentener5

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.

3 State Key Laboratory of Earth Surface Processes and Resource Ecology, and College of Resources Science & Technology, Beijing Normal University, Xinjiekouwai Street 19#, Beijing, 100875, China.

4 Karlsruhe Institute of Technology, Institute for Meteorology and Climate Research (IMK-IFU), Kreuzeckbahnstrasse 19, 82467 Garmisch-Partenkirchen, Germany.

5 Joint Research Centre, Institute for Environment and Sustainability, Ispra, Italy.


The net impact of human nitrogen (N) fixation on climate (ignoring short-lived components) mainly depends on the magnitude of the warming effect of (direct and indirect) nitrous oxide (N2O) emissions and the cooling effect of N-induced carbon dioxide (CO2) uptake. N-induced CO2 uptake is caused by anthropogenic N deposition which increases net primary production (NPP) in N-limited ecosystems and thus CO2 sequestration. Nitrogen oxide (NOx) emissions, however, also induce tropospheric ozone (O3) formation, and elevated O3 concentrations reduce NPP and thus plant C sequestration. We estimated global-scale impacts of anthropogenic N fixation on net greenhouse gas emissions using recent data and modelling approaches with respect to N inputs to various ecosystems, N2O emissions in response to N inputs, and C exchange in responses to N inputs (C–N response) and O3 exposure (C–O3 response). The estimated impact of human N fixation is dominated by an increase in N2O emissions equal to 1.02 (0.89–1.15) Pg CO2-C equivalent (eq) yr-1. CO2 uptake due to N inputs to terrestrial and aquatic ecosystems corresponds to net emissions of -0.75 (-0.97 to -0.56) Pg CO2-Ceq yr-1, while the reduction in CO2 uptake by N-induced O3 exposure corresponds to net emissions of 0.14 (0.07–0.21) Pg CO2-Ceq yr-1. Overall, human N fixation causes an increase in net greenhouse gas emissions of 0.41 (-0.01–0.80) Pg CO2-Ceq yr-1. Even considering all uncertainties, it is likely that N inputs lead to a net increase in greenhouse gas emissions.

Evaluating the use of a web-based nitrogen cycle animation

Mark Imhof1, Gemma Heemskerk2 and Matthew Cox3

1 Agriculture Victoria, Department of Economic Development, Jobs, Transport and Resources. 32 Lincoln Square Nth, Parkville, Victoria 3053. 

2 Agriculture Victoria, Department of Economic Development, Jobs, Transport and Resources. 32 Lincoln Square Nth, Parkville, Victoria 3053. 

3 Agriculture Victoria, Department of Economic Development, Jobs, Transport and Resources. 32 Lincoln Square Nth, Parkville, Victoria 3053. 


An interactive animation of the nitrogen (N) cycle, within the context of a dairy agroecosystem, is available on the Victorian Resources Online website at: It is one of a series of animations developed to capture and communicate soil knowledge and visually explain processes that occur in the soil and landscape. Animations were created from ‘storyboards’ (a series of hand-drawn sketches that outline all the events in the animation) developed with relevant soil scientists. This is an example of harnessing tacit knowledge of scientists, and providing context, to create an information product aimed at a broad range of users. Feedback to date has highlighted the value to users involved in agricultural extension and education. User profiling (based on IP address tracking) for a three-month period in 2013 indicated that the N cycle animation was the most extensively accessed of all animations on the website. The education and government sectors were significant user groups.

Do environmental scientists behave more environmentally friendly with regard to nitrogen pollution?

Adrian Leip1, Claudia Marques dos Santos Cordovil2 , Patrick Musinguzi3, Ina Körner4

1 European Commission, Joint Research Centre, Institute for Environment and Sustainability, Via Fermi 2749, TP 266/040

I-21027 ISPRA (VA), Italy,,

2 Universidade de Lisboa, Instituto Superior de Agronomia, LEAF, Tapada da Ajuda, 1349-017 Lisboa, Portugal

3 Department of Agricultural Production, School of Agricultural Sciences, Makerere University, Kampala, Uganda

4 Hamburg University of Technology, Institute of Wastewater Management and Water Protection; Bioconversion and Emission Control Group, 21073 Hamburg, Germany


Nitrogen neutrality is a novel concept that aims at reducing the N-footprint caused by an entity and offsetting the residual emission of reactive nitrogen (Nr). This concept had been applied to three conferences (6th International Nitrogen Conference in 2013 in Kampala, Uganda; 18th Nitrogen Workshop in 2014 in Lisbon, Portugal; 15th Ramiran Conference in Hamburg, Germany) with different concepts and different degree of willingness of the participants to contribute to the voluntary compensation fee. This paper analyses the results of surveys made among the participants of the conferences to understand their view on low-impact conferences, N-footprints, and the N-neutrality concept.

The effect of ecosystem engineers on N cycling in an arid agroecosystem

Jessica G. Ernakovich1, Theodore A. Evans2, Ben Macdonald3, Mark Farrell4

1 CSIRO Agriculture & Food, PMB 2, Urrbrae, SA, 5064,,

2 School of Animal Biology, University of Western Australia, Perth, WA 6009,

3 CSIRO Agriculture & Food, Canberra, ACT, 2601,

4 CSIRO Agriculture & Food, PMB 2, Urrbrae, SA, 5064,,


Ecosystem engineers—such as earthworms, termites and ants—are an important component of soil biodiversity and have been shown to contribute to aboveground productivity in native and managed ecosystems. Although their role in physical alteration of soils is appreciated, less is known about their effect on soil nutrient cycling, particularly in arid systems where termites and ants are the dominant ecosystem engineers. We explored the effect of termite reduction and tillage on soil nitrogen (N) biogeochemistry in soils from the northeasternmost wheat growing region in Western Australia. We assessed total soil N, potentially mineralizable N, and dissolved N pools, as well as soil N fluxes, such as proteolysis and N mineralization. We predicted that soils with native termite and ant populations would have greater N pools and rates of transformations between pools. While we found that many soil N pools were up to 2.5 times larger with native termite populations (e.g. dissolved organic N, NH4+), we found that the rate of transformations between pools was reduced relative to the reduced termite plots. While the reason behind this trend needs further exploration, the larger soil N pools in sites with native levels of ecosystem engineers implies that the conservation of soil macrofauna, particularly those that translocate N through the soil profile, may be important in the sustainable management of cropped lands.

Colorado State University Nitrogen Footprint Project

Jacob Kimiecik1, Jill Baron2

 1 Colorado State University, Fort Collins, CO, 80523-1499

2 USGS, Colorado State University, Fort Collins, CO, 80523-1499



Universities are a significant source of nitrogen that is released to the environment leading to environmental harm.  Colorado State University (CSU) is a large land grant institution working toward sustainability goals, and in 2014 added a goal of reducing its nitrogen (N) footprint. The CSU released N to the environment during the period August 2014-August 2015 from utilities, transportation, housing and dining, research animals, and research farms. The N footprint came to 1,066 metric tons N, of which only 28% was caused by on-campus activities. Most of CSU’s N footprint comes from Agricultural Experiment Stations and other research facilities around Colorado. Because of agricultural activity, CSU has a higher N-footprint by an order of magnitude than other universities that are part of the Nitrogen Footprint Network. On the university campus food production, utilities, and research animals are the largest sources of released N, and we describe an active program of education, incentives, and linking N reductions to greenhouse gas reductions.

Key Words

university, abatement, nitrogen footprint network, agricultural research

Nitrogen footprint updates in Japan: Significance of global trades and food culture

Hideaki Shibata1, Azusa Oita2

1 Field Science Center for Northern Biosphere, Hokkaido University, Kita-9, Nishi-9, Kita-ku, Sapporo, 060-0809, Japan,

2 Graduate School of Environment and Information Science, Yokohama National University, 79-7 Tokiwadai, Hodogaya, Yokohama 240-8501, Japan


Nitrogen (N) footprint is a powerful parameter to understand loss of reactive N (i.e. all forms of nitrogen except N2) to the environment by use of food, and energy in human’s daily life. The amount and composition of the N footprint differs among communities, countries and regions depending on various factors such as environment, economy, technological development and their culture. Japan is the top net importer of embodied reactive N emissions in food, feed, energy, and goods among countries, resulting in large loss of reactive N to the environment both inside and outside of Japan. Here we present updated information of N footprint in Japan by synthesizing the recent research findings. Virtual N factors (VNFs) of meat processed food in Japan are mostly higher than those in other countries while fish and seafood (especially wild-caught fish) is also important source of animal protein with generally lower VNFs than that of animal meat. It was suggested that shifting consumer preferences from meat- and dairy-intensive diets to diets with more fish and vegetables would have potential to reduce the N footprint in Japan. Increase of N use efficiency during production, processing, and consumption of food through technological improvements in agriculture and food industries with changes in personal dietary choices are needed to decrease loss of reactive N to the environment both in Japan and countries that provide food and feed to meet demand of Japan.

Comparing nitrogen budgets in shrimp and rice-shrimp ponds in Vietnam

Duc Dien Luu1,2, Huu Hiep Le2, Michele A. Burford1, Jesmond Sammut3

1 Australian Rivers Institute, Griffith University, 170 Kessels Road, Nathan, Queensland 4111, Australia,, Email:
2 Research Institute for Aquaculture No.2, 116 Nguyen Dinh Chieu Street, District 1, Ho Chi Minh City, Vietnam
3 School of Biological, Earth and Environmental Sciences, University of New South Wales, Kensington 2052, Australia


Saline water intrusion has become a severe issue facing the Mekong region of Vietnam, especially in coastal areas. This issue has resulted in farmers diversifying from growing exclusively rice to adopting integrated rice-shrimp culture systems. However, the nitrogen (N) cycling and N use efficiency of these systems remains poorly understood. To address this knowledge gap, we examined nutrient budgets across 12 farms adopting integrated rice-shrimp ponds or intensive grow-out ponds over a one year period. The main N input (95%) in the rice-shrimp ponds came from inlet water, while only 2% of N in outlet water was due to shrimp farming. Shrimp survival rates in mixed rice-shrimp systems were low over the year (4.3 – 5.6%). In contrast, intensive grow-out ponds growing only shrimp on the same farms had significantly higher survival rates (66.4 – 82.3%) when the crop survived through to harvest. In these ponds, formulated feed was the highest input (65% N) with 44% N being in shrimp harvest. These results show that N in the rice-shrimp ponds was used less efficiently than in grow-out ponds and that mechanisms to improve survival rates and production are urgently needed.

Surface atmosphere exchange of NO and CO2 in a grazed semi-arid ecosystem: comparison of measurements and model predictions

Claire Delon1*, Corinne Galy-Lacaux1, Dominique Serça1, Ndiobo Camara2, Eric Gardrat1, Idrissa Saneh3, Rasmus Fensholt4, Torbern Tagesson4, Valérie Le Dantec5, Bienvenu Sambou2, Cheikh Diop2, Manuela Grippa6, Eric Mougin6.

1 Laboratoire d’Aerologie, Université de Toulouse, CNRS, UPS, France, *

2 Institut des Sciences de l’Environnement, Université Cheick Anta Diop, Dakar, Sénégal

3 Centre de Recherche Zootechnique, Dahra, Sénégal

4 Institute of Geography, University of Copenhagen, Copenhagen, Danemark

5 Centre d’Etudes Spatiales de le BIOsphère, Université de Toulouse, CNES, CNRS, IRD, UPS, France

6 Geosciences Environnement Toulouse, Université de Toulouse, CNES, CNRS, IRD, UPS, France


This paper presents a comparison between measurements and model predictions of biogenic nitric oxide emissions and respiration (CO2 emissions) from soils in a Sahelian grazed ecosystem in Senegal (Dahra site, 15.2°N, 15.2°W). Nitric oxide (NO) and CO2 emissions are large at the beginning of the wet season when the first rains fall on dry soils (pulse emissions), due to microbial and biological processes reactivated in the soil when moisture conditions are favourable. The model shows a correct representation of pulses of NO and CO2, but underestimates fluxes in the drier periods between rain events and after the wet season. We hypothesize that in the drier periods the model over-predicts the death rate of microbes, involving a lag between mineral N content availability and N emissions. Spatial heterogeneity of soil and vegetation characteristics and presence of livestock also involve differences between modelled and measured fluxes.