Feature Presentation | INI 2016

Benchmarking and mitigation of nitrous oxide emissions in temperate vegetable cropping systems in Australia resulting in improved nitrogen use efficiency

2016 INI, Cropping systems and nitrogen efficiency, Feature Presentation

Ian Porter¹ and David Riches¹

¹School of Life Sciences, La Trobe University, Bundoora, Vic 3086, Australia, i.porter@latrobe.edu.au

Abstract

Vegetable producers in some temperate regions of Australia use up to 1 tonne of nitrogen (N) as inorganic (fertilizers) and organic N (chicken manure) to produce 3 to 4 crops from the same land each year. Trials in Victoria showed great potential to reduce N inputs and to mitigate N₂O losses from soil by use of nitrification inhibitors on manures and fertilizers compared to the standard grower practice (SGP) used at the sites without reducing yield. Annual N₂O emissions ranged from 9.1 to 12.5 kg-N/ha for the unfertilized soil, and the combined fertiliser and manure program, respectively. Higher daily emission rates occurred when manures were applied to the soil and these were up to 20-fold greater for a single event than those from fertilizers. The inhibitors, DMPP and to a lesser extent 3MP/TZ, reduced N₂O emissions from the fertilizer and manure program, with a maximum reduction of 64% occurring over the three crops, compared to the SGP. Pre-plant application of chicken manure resulted in short periods where daily N₂O fluxes ranged from 70-213 g N₂O-N/day and DMPP reduced the net N₂O cumulative emission by 53% over this period. Annual cumulative N₂O emissions were up to 40-fold higher at the Victorian site than reported in similar trials in Queensland and Tasmania. The Emission Factor of 0.45% from the SGP was considerably lower than the IPCC default value (1% of N applied). Nitrogen measurements indicate that up to 60% of the applied N may be lost to the atmosphere or leached in high N use vegetable systems in Victoria.

Nitrate-N losses in drainage water under irrigated vertosols of north-western NSW

2016 INI, Cropping systems and nitrogen efficiency, Feature Presentation

Tim Weaver¹, Nilantha Hulugalle², Hossein Ghadiri³, Steven Harden⁴

¹NSW Department of Primary Industries, Locked Bag 1000, Narrabri, NSW 2390, www.dpi.nsw.gov.au, tim.weaver@dpi.nsw.gov.au

²Fenner School for the Environment and Society, Australian National University, Canberra, ACT 0200

³Griffith School of Environment, Environmental Futures Research Institute, Griffith University, Nathan, Qld 4111

⁴NSW Department of Primary Industries, Calala, NSW 2340

Abstract

A comparison on the effects of soil and crop management practices in irrigated farming systems on the quality of drainage water in Vertosols has not been reported in the literature. The objective of this study was to quantify nitrate-N in drainage water in the subsoil (0.6, 0.9, 1.2 m) of sodic and non-sodic Vertosols under selected crop rotations, viz. continuous cotton (Gossypium hirsutum L.), cotton–dolichos (Lablab purpureus L.) and cotton–wheat (Triticum aestivum L.). A cotton–wheat rotation was sown at Wee Waa and Myall Vale; wheat stubble was incorporated in the former and retained as in situ mulch in the latter. At Merah North, there were three cropping sequences; viz. continuous cotton, cotton–wheat, and cotton–dolichos sown between 1993 and 2000 in adjacent plots with identical land management histories. The three treatments were sown with cotton during the 2000–2001 and 2002–2003 growing seasons, wheat during the 2001 winter and sorghum during the 2001–2002 growing season with stubble being incorporated. Drainage water was sampled with 50-mm diameter ceramic-cup samplers from depths of 0.6, 0.9 and 1.2m in six sites in each plot and irrigation water from the head ditch after irrigation between mid-October and late February during the cotton-growing seasons of 2000-2001 and 2002–2003. Soil water extracted from the ceramic-cup samplers was analysed for nitrate-N. The nitrate-N concentrations in drainage water varied among sites, and reflected variations in soil properties, fallow length since the preceding crop, fallow rainfall and irrigation water quality.

Rootzone reality – A network of fluxmeters measuring nitrogen losses under cropping rotations

2016 INI, Cropping systems and nitrogen efficiency, Feature Presentation

Norris M¹, Johnstone P¹, Green S², Clemens G³, van den Dijssel C², Wright P⁴, Clark G⁴, Thomas S³, Williams R³, Mathers D⁵ and Halliday A⁶

¹The New Zealand Institute for Plant & Food Research Limited, Havelock North, 4130

²The New Zealand Institute for Plant & Food Research Limited, Palmerston North, 4474

³The New Zealand Institute for Plant & Food Research Limited, Lincoln, 7608

⁴The New Zealand Institute for Plant & Food Research Limited, Pukekohe, 2676

⁵Foundation for Arable Research, Havelock North, 4130

⁶Horticulture New Zealand, Wellington, 6011

Email: Paul.Johnstone@plantandfood.co.nz

Abstract

Nutrient losses are an important economic and environmental consideration across the New Zealand cropping sector. Between August 2014 and May 2015 we established a network of passive-wick drainage fluxmeters (DFMs) on commercial cropping farms in the Canterbury, Manawatu, Hawke’s Bay and Waikato/Auckland regions to measure nitrogen (N) losses in drainage water below the root zone. Results from this study will provide growers and regional authorities with measured N losses from cropping farms across a range of sites and seasons. The experimental design across the DFM network includes three sites each across four monitor regions, and uses 12 fluxmeters per site. Individual sites were chosen to provide a range of cropping systems, soil types, climatic conditions and management practices relevant to each region. Across the DFM network, measured losses have ranged from 0.2 kg N/ha to 226 kg N/ha for the period between DFM installation and 30 September 2015 with N lost primarily in the Nitrate-N form. Most drainage (78–100%) occurred over the mid-autumn to early spring period (April to September). Variability in N losses between sites reflect the duration of the monitoring period (five to 13 months) as well as the wide range of climate, management and soil characteristics.

Fates of applied nitrogen fertilizer after harvesting wheat on dryland soil

2016 INI, Cropping systems and nitrogen efficiency, Feature Presentation

Jianbin Zhou¹, Bin Liang^1,2, Wei Zhao^{1, 3}, Mengjie Xia¹, Xueyun Yang¹

¹College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi 712100, China;

Key Laboratory of Plant Nutrition and the Agri-environment in Northwest China, Ministry of Agriculture, Yangling, Shaanxi 712100, China

²College of Resources and Environmental Sciences, Qingdao Agriculture University, Qingdao, Shandong 266109, China

³Weinan Agricultural Technology Extension Service Center, Weinan, Shaanxi 714000, China

Abstract

About one third of nitrogen (N) fertilizer is retained in the soil after crop harvest. Understanding the fate of this residual fertilizer N in soil is important for evaluating its overall use efficiency and environmental effects. In this study, the ¹⁵N-labelled fertilizer was applied to winter-wheat growing in three different fertilizedsoils (No-F, no fertilizer; NPK, inorganic NPK fertilization; and MNPK, manure plus inorganic NPK fertilization) from a long-term trial (19-year) on the south edge of the Loess Plateau, China. The fate of residual ¹⁵N in soils over summer fallow and the second winter-wheat growing season was followed. The amount of the residual N in the No-F soil was significantly higher than that in the NPK and MNPK soils after harvesting the first wheat crop. The forms of the residual N in the No-F soil was mainly in mineral form; and for the NPK and MNPK soils, they were mainly in organic form. The loss of ¹⁵N in No-F soil over the summer fallow was as high as 33%, and significantly higher than that in the NPK soil (8%) and MNPK soil (5%). The residual ¹⁵N use efficiency by the winter-wheat in the second cropping were equivalent to 9.0%, 2.0% and 2.2% of the originally applied¹⁵N. A high proportion of the residual ¹⁵N was lost during the summer fallow in dryland farming. Better management of the residual N in soil during the summer fallow is required, its contribution to subsequent cropsis also deserved consideration when makingN fertilizer recommendation.

Ammonia deposition in the neighbourhood of an intensive cattle feedlot in Victoria, Australia

2016 INI, Feature Presentation, Reactive nitrogen deposition

Jianlin Shen¹, Deli Chen², Mei Bai², Jianlei Sun², Trevor Coates², Shu Kee Lam², Yong Li¹

¹ Key Laboratory of Agro-Ecological Processes in Subtropical Regions, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125, China (E-mail: jlshen@isa.ac.cn)

² Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Victoria 3010, Australia (Email: delichen@unimelb.edu.au)

Abstract

We conducted the first study in Australia to measure ammonia (NH₃) deposition within 1 km from a commercial beef feedlot in Victoria. NH₃ concentrations and deposition fluxes decreased exponentially with distance away from the feedlot. The mean NH₃ concentrations decreased from 419 µg N m^-3 at 50 m to 36 µg N m^-3at 1 km, while the mean NH₃ dry deposition fluxes decreased from 2.38 µg N m^-2 s^-1 at 50 m to 0.20 µg N m^-2 s^-1 at 1 km downwind from the feedlot. These results extrapolate to NH₃ deposition of 53.9 tonne N yr^-1 in the area within 1 km from the feedlot, accounting for 8% of the annual NH₃-N emissions from the feedlot. This high NH₃ deposition rate nearby the cattle feedlot had caused the increase of soil inorganic nitrogen content, especially for NO₃^– (from 33 mg N kg^-1at 1000 m from the feedlot to 124 mg N kg^-1 at 50 m from the feedlot). Higher N content (4.0% to 5.7%) in the above-ground part of grassland species and high cover rate of single species (e.g. a cover rate of 31% to 42% at 50 to 200 m from the feedlot for Cymbonotus lawsonianus) were found in the grassland transect to the southeast of the feedlot. Our results suggest that NH₃deposition is significant nitrogen (N) nutrient input for surrounding croplands and natural ecosystems.

Twelve years of nitrogen deposition gap? An EMEP4UK model analysis

2016 INI, Feature Presentation, Reactive nitrogen deposition

Massimo Vieno¹, Mark Sutton¹, Mathew Heal², Anthony Dore¹, Rachel Beck¹, David Fowler¹, Rognvald Smith¹, and Stefan Reis¹

¹Natural Environment Research Council, Centre for Ecology & Hydrology, Penicuik, UK, www.ceh.ac.uk

²School of Chemistry, University of Edinburgh, Edinburgh, UK, www.ed.ac.uk

Abstract

An analysis of 12 years of annual nitrogen and sulphur deposition over the UK was carried out comparing atmospheric chemistry transport model (ACTM) results with an observation-derived calculation (CBED). The two deposition estimates agree well for oxidised sulphur, whereas total oxidised nitrogen deposition was underestimated by the ACTM. Possible causes of this discrepancy are the uncertainties of emissions estimates and the simplification in the ACTM aerosols formation. The CBED deposition estimates are less sensitive to uncertainties in the emissions inventory dataset as the UK deposition values are derived from observed deposition and surface concentrations. However, CBED wet deposition may be over-estimated due to dry deposition to the surface of bulk collectors. The UK deposition estimates show a general decline over the 2000-2012 period investigated; for oxidised sulphur ~86 (ACTM) and ~97 (CBED) Gg S yr^-1, for oxidised nitrogen ~29 (ACTM) and ~45 (CBED) Gg N yr^-1, and for reduced nitrogen ~7 (ACTM) and ~5 (CBED) Gg N yr^-1.

Trends of monitored nitrogen species at monitoring sites in North America

2016 INI, Feature Presentation, Reactive nitrogen deposition

Leiming Zhang¹, Irene Cheng¹, Xiaohong Yao²

¹Air Quality Research Division, Environment and Climate Change Canada, Toronto (leiming.zhang@canada.ca)

²Ocean University of China, Qingdao, China

Abstract

Long-term (1983-2011) air concentrations and annual wet deposition of ammonium and nitrate at 30 Canadian sites were analyzed. Long-term median atmospheric NH₄⁺ and NO₃^– ranged from 0.1-1.7 and 0.03-2.0 µg/m³ among the sites, respectively. Median annual wet deposition varied from 0.2-5.8 and 0.8-23.3 kg/ha for NH₄⁺ and NO₃^–, respectively. Long-term decline in atmospheric NH₄⁺ from 1994-2010 was observed, whereas atmospheric NO₃^– increased from 1991-2001 and then declined from 2001-2010. Annual wet deposition of NO₃^– decreased at most sites by 0.07-1.0 kg/ha/a. Average gaseous HNO₃ and particulate NO₃^–wet scavenging contributions to nitrate wet deposition were 72±23% and 28±23%, respectively. Gaseous NH₃and particulate NH₄⁺contributed 30±19% and 70±19% to wet NH₄⁺deposition.

Interannual variabilities in atmospheric ammonia during the most recent seven to eleven years were investigated at fourteen sites across North America. The long-term average of NH₃ ranged from 0.8 to 2.6 ppb among the four urban and two rural/agriculture sites in Canada. The annual average at these sites did not show any deceasing trend with largely decreasing anthropogenic NH₃emission. An increasing trend was actually identified from 2003 to 2014 at one urban site. In the U.S., average NH₃ from 2008 to 2015 was 2.2-4.9 ppb at three rural/agriculture sites and was 0.3-0.5 ppb at four remote sites. A stable trend at one and increasing trends at three rural/agricultural sites were identified. Increasing trends at the four remote sites were also identified. Changes in NH₄⁺/NH₃ partitioning and/or air-surface exchange process as a result of the decreased sulfur emission and increased ambient temperature were believed to be the causes of NH₃ at some of the sites

Anthropogenic aerosol depositions of nitrogen and phosphorus reduces the sensitivity of oceanic productivity to warming

2016 INI, Feature Presentation, Reactive nitrogen deposition

Feng Zhou¹, Rong Wang^1,2, Yves Balkanski², Laurent Bopp², Philippe Ciais²

¹Sino-France Institute of Earth Systems Science, Laboratory for Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing, 100871, P.R. China, Email: zhouf@pku.edu.cn

² Laboratoire des Sciences du Climat et de l’Environnement, CEA CNRS UVSQ, 91191 Gif-sur-Yvette, France

Abstract

Satellite data reveal a strong link between contemporary oceanic productivity and climate. Models suggest oceanic productivity is reduced in response to enhanced water stratification induced by warming, but do not include the effect of increasing anthropogenic aerosol depositions of nitrogen and phosphorus (AAD). We model the response of oceanic productivity and chlorophyll to AAD, supported by in situ nutrient and chlorophyll measurements. As a result, AAD reduces the sensitivity of oceanic productivity to sea-surface temperature from -15.2±1.8 to -13.3±1.6 Pg C y^-1°C^-1in the stratified ocean during 1948-2007. The reduction over the North Atlantic, North Pacific and Indian oceans reaches 40, 24 and 25%, respectively. We hypothesize that future reduction of aerosol emissions in response to higher air-quality standards will accelerate the decline of oceanic productivity per unit warming.

Evaluating the Taiwanese Nitrogen Footprint of Food Production

2016 INI, Feature Presentation, National and community nitrogen footprints

Ming-Chien Su¹, Hideaki Shibata², James N Galloway³, Allison M Leach⁴

¹Department of Natural Resources and Environmental Studies, National Dong Hwa University, No. 1, Sec.2, Da Hsueh Rd, Shoufeng, Hualien 97401, Taiwan , mcsu@mail.ndhu.edu.tw

² Field Center for Northern Biosphere, Hokkaido University; Kita-9, Nishi-9, Kita-ku, Sapporo, Hokkaido 060-0809, Japan

³ Environmental Sciences Department, University of Virginia, Charlottesville, VA 22904, USA

⁴ Department of Natural Resources and the Environment, University of New Hampshire, Durham, New Hampshire 03824, USA

Abstract

The emissions of reactive nitrogen (Nr) have been well known to cause many environmental problems and human health issues. Recently, the nitrogen (N) footprint indicator has been developed and used to specify the influence of the human use of reactive nitrogen on the environment. Taiwan’s Virtual Nitrogen Factors (VNFs; factors that describe average N losses during food production by food type) are similar to Japan’s VNFs (without accounting for trade) possibly due to comparable dietary and farming technologies. The average VNF of fruit is much higher than other vegetable products. Comparisons of the VNFs between Taiwan and Japan (without trade) follow the same pattern. The 10-year average total food production N footprint in Taiwan was 28 kg N/capita/yr. Furthermore, the N footprints for vegetable and animal products were 10 and 18 kg N/capita/yr, respectively. The results showed that the Taiwan N footprint is highly dependent on food production processes per unit of Nr consumed. We are focusing on domestic food production in Taiwan, but a next step for this study will be to also consider where the food consumed in Taiwan was produced (e.g., imports).

Nitrogen surplus: An environmental performance indicator for sustainable food supply chains

2016 INI, Feature Presentation, National and community nitrogen footprints

Eileen L. McLellan¹, Ken Cassman², Shai Sela³, Harold van Es³, Rebecca Marjerison³, Rod Venterea⁴, Christina Tonitto³ and Peter Woodbury³.

¹Environmental Defense Fund, 1875 Connecticut Avenue, Washington, D.C. 2009, www.edf.org, emclellan@edf.org

² University of Nebraska, Plant Science Hall, Lincoln, NE 68583

³Soil and Crop Sciences, Bradfield Hall, Cornell University, Ithaca, NY 14853

⁴USDA-ARS Soil and Water Management Research Unit, Borlaug Hall, 1991 Upper Buford Circle, St. Paul MN 55108

Abstract

Nitrogen pollution and its negative impacts on human and environmental health are embedded in commodities traded domestically and internationally; we focus on grain because of its importance as a feedstock for food, feed and fuel. Food supply chain companies, in particular retailers and food processors, can play a catalytic role in reducing that burden through sustainable sourcing of grain and grain-derived products. We describe how such sourcing commitments might work to reduce N losses and how progress towards them can be tracked using a simple, robust and scalable indicator: N surplus. Using model simulations and empirical data on U.S. maize production, we show that N surplus, the difference between annual N inputs (fertilizer, manure, biological nitrogen fixation) and grain N outputs, is strongly related to N losses at field to regional scales. This analysis suggests that supply chain companies can set performance goals related to reductions in N surplus, which in turn could translate into large improvements in environmental outcomes. Recognizing that individual producers will need guidance and motivation on how to reduce N surplus, we present a conceptual model for using farmer-derived data in a social learning context to identify combinations of management practices that most effectively reduce N losses and improve crop yield or profit.