Impact Presentation | INI 2016

Towards a complete nitrogen budget from subtropical dairy farms: three years of pasture nitrogen losses in surface runoff

2016 INI, Effects of reactive nitrogen on ecosystems, Impact Presentation

David Rowlings¹, Martin Labadz¹, Clemens Scheer¹, Peter Grace¹

¹Queensland University of Technology, 2 George Street Brisbane, Queensland, 4000, d.rowlings@qut.edu.au

Abstract

Dairy represents one of the most intensive and nitrogen (N) loaded production systems in the high rainfall regions of Queensland, Australia. Fertiliser application rates during the winter rye grass season (April-October) frequently surpass 300 kg N ha^-1 year^-1 yet the fate of much of the applied N is uncertain. The high (>1200 mm year^-1) and intensive rainfall and the proximity to environmentally sensitive areas such as the Great Barrier Reef make losses in surface water run-off of particular interest to the industry. Two run-off plots (416 m²) were installed on an intensively irrigated and fertilised rye-grass/kikuyu pasture rotation near Gympie, Queensland and monitored over three (1 June to 31 May) measurement years. Runoff was measured using a tipping bucket and nutrients collected via an automated sampler. Runoff and losses were largest during the 2012-13 season when five of the nine runoff events over the measurement period occurred and total runoff exceeded 480 mm, corresponding to 37% of the annual rainfall. Total N load was dominated by NO₃^–, with largest losses during a four day, 448 mm rain event in January 2013 following an extended dry period resulting in 280 mm of runoff and 16.5 kg ha^-1 of N losses. Total N losses over the remaining periods were typically negligible (< 1 kg ha^-1 event^-1), with annual losses of 5.0 and 0.7 kg N ha^-1 for 2013-14 and 2014-15 respectively. These results indicate that under current management systems intensive pastures contribute only minor nutrient loads, though losses can be high following extended dry periods.

Is lichen δ15N an indicator of nitrogen pollution and a surrogate of nitrogen atmospheric composition? Evidence from manipulative experiments

2016 INI, Effects of reactive nitrogen on ecosystems, Impact Presentation

Silvana Munzi¹, Cristina Branquinho¹, Cristina Cruz¹, Cristina Máguas¹, Ian Leith², Lucy Sheppard², Mark Sutton²

¹ Centre for Ecology, Evolution and Environmental Changes (cE3c), Faculdade de Ciências, Universidade de Lisboa, Bloco C2, 5º Piso, sala 2.5.14, 1749-016 Lisbon, Portugal

² Centre for Ecology & Hydrology (CEH) Edinburgh, Bush Estate, Penicuik, EH26 0QB, UK

Abstract

Due to the relevance of nitrogen (N) as a pollutant, setting up an effective method to determine spatial distribution of N sources would help to develop management and mitigation strategies. Although promising, the use of isotopic signature of lichens to map atmospheric N deposition is still difficult due to the synergism between climatic and anthropogenic factors and the superimposition of multiple N sources. To understand how lichen’s isotopic signature is affected by N, thalli of the sensitive Evernia prunastri and of the tolerant Xanthoria parietina were exposed for ten weeks to different forms and doses of N in a manipulative experiment, and physiological parameters, total N, δ¹⁵N and chlorophyll a fluorescence were measured. In parallel, thalli of Cladonia portentosa exposed to the same treatments for 11 years or 6 months were analyzed to investigate the role of time of exposure. Our results showed that lichen N content and δ¹⁵N were correlated with the N dose of the N treatments and that lichen δ¹⁵N tended to become similar to the source’s signature. However, nitrophytic and acidophytic species showed different δ¹⁵N in response to the same treatments, probably due to their cation exchange capacity. Finally, the correlation between N content and δ¹⁵N was higher in case of long-term exposure. Nitrogen isotopic signature in lichens can potentially be used as indicator to determine spatial distribution of N sources in the field. However, further investigation is needed to confirm these results in the field, and species functional traits must be taken in particular consideration.

High N retention in Mediterranean catchments enhanced by water management practices

2016 INI, Effects of reactive nitrogen on ecosystems, Impact Presentation

Estela Romero*^1,2, Josette Garnier^1,3, Gilles Billen^1,3, Franz Peters², Luis Lassaletta^1,4

¹Université Pierre et Marie Curie (UPMC), UMR 7619 Metis, Paris, 75005, France. Email: estela.romero@upmc.fr

² Institut de Ciències del Mar (CSIC), Barcelona, 08003, Spain

³ Centre National de la Recherche Scientifique (CNRS), UMR 7619 Metis, Paris, 75005, France

⁴ PBL, Netherlands Environmental Assessment Agency, 3721 MA, Bilthoven, The Netherlands

Abstract

The share of nitrogen (N) that is exported to the sea or accumulated on land (N retention, sensu lato) involves different environmental processes; coastal eutrophication and anoxia in the first case; the acidification of soils, the emission of ammonia and greenhouse gases, and the pollution of aquifers in the latter. Nevertheless, the factors involved in N retention are still poorly constrained, particularly in arid and semi-arid systems. The present study evaluates the N fluxes of 38 catchments on the Iberian Peninsula with contrasting climatic characteristics (temperate and Mediterranean), land uses, and water management practices. The contribution of physical and socio-ecological factors in the retention of N was partitioned, and the link between N retention and water regulation was explored. We hypothesize that the extreme flow regulation performed in the Mediterranean enhances the high N retention values associated with arid and semi-arid regions. Our results show that reservoirs and irrigation channels account for >50% of the variability in N retention values, and above a certain regulation threshold, N retention peaks to values >85-90%. Future climate projections forecast a decrease in rainfall and an increase in agricultural intensification and irrigation practices in many world regions, and notably in arid and semi-arid areas. Increased water demands will likely lead to a higher flow regulation, and the situation may resemble that of Mediterranean Iberian Peninsula catchments. High N retention and the associated environmental risks must therefore be considered as an important consequence of water regulation practices, and must be adequately managed.

Nitrogen species distribution in groundwater: A review of historical data with recent sampling in the Gippsland, Victoria (Australia

2016 INI, Impact Presentation, Nitrogen science and policy

Michael Adelana¹, Michael Heaven², Mark Holmberg³, Matt Kitching⁴, George Croatto⁴

Agriculture Victoria, Department of Economic Development, Jobs, Transport and Resources

¹ 32 Lincoln Square North, Parkville, Victoria 3053, Michael.Adelana@ecodev.vic.gov.au

²1301 Hazeldean Road, Ellinbank, Victoria 3821, Australia

³Cnr Taylor Street & Midland Highway, Bendigo, Victoria 3554

⁴Terrace 4, Ernest Jones Drive, Macleod, Victoria 3085

Abstract

In agricultural regions diffuse pollution by nitrate is considered one of the main causes of groundwater quality deterioration. For agricultural systems that are pasture based, the input loads (e.g. fertiliser, cow dung and urine) can result in loss of nutrients. Hence, shallow groundwater aquifers in agricultural areas are susceptible to nitrate contamination from losses of N by leaching. A review of historical data, together with recent sampling, was carried out in the Gippsland region of Victoria to map distribution of N-species in shallow aquifer systems. This review revealed that there is limited routine monitoring of nitrate in groundwater. Nevertheless, based on the limited historical spatial and temporal groundwater chemistry data available, the concentrations of nitrate and ammonium are generally below Australian water quality (ANZECC) limits in the shallow unconfined aquifer in West Gippsland. However, localized clusters of values higher than the ANZECC limit exist in alluvium near Mitchell River, East Gippsland. In all confined deep aquifer samples the concentrations were found to decrease further. An analysis of groundwater chemistry could not identify a correlation between land use or soil and the concentrations of groundwater nitrate and total nitrogen. Only shallow piezometer samples at Willow Grove, West Gippsland suggested high nitrate reductions under intensely grazed dairy soils. Site-specific piezometer studies would be required to determine the depth of influence below the soil zone for reduction of nitrate to acceptable concentrations.

The preliminary Danish nitrogen footprint -Applying nitrogen footprints and using policy scenarios to change behavior

2016 INI, Impact Presentation, Nitrogen science and policy

Morten Graversgaard¹, Tommy Dalgaard¹, Allison M. Leach², Lia R. Cattaneo³, James N. Galloway³

¹Department of Agroecology, Aarhus University, Blichers Allé 20, Tjele DK-8830, Denmark, morten.graversgaard@agro.au.dk

² Department of Natural Resources & the Environment, University of New Hampshire, Durham, NH 03824, USA

³Department of Environmental Sciences, University of Virginia, 291 McCormick Rd, Charlottesville, VA 22904, USA

In the past century, human activity has reshaped the global nitrogen (N) cycle, so that the anthropogenic changes to the N cycle have already crossed the safe operating space for the stability of earth system processes. Consumer driven, integrated practice and policy solutions are needed to achieve N source control and mitigation of the unintended consequences of excess N. This paper presents the preliminary results of the first approach to the Danish N footprint model to build awareness of protein consumption and embedded N in Danish society. Denmark’s agriculture has a high meat export-production which have resulted in local N pollution problems. These unintended consequences of meat production in Denmark have raised awareness among citizens, non-governmental organizations (NGOs) and politicians to deal with the problem in an integrated manner. There is a growing interest in finding the right suit of policy measures to reduce meat consumption and N pollution in Denmark. In this paper the preliminary Danish N-footprint results will be compared and modelled through 7 policy scenarios (three food production scenarios, one food consumption, one food waste, one energy and one transportation scenario) to find out how policies on protein consumption and N can contribute to a more sustainable pathway in Denmark.

Polymer Coated Urea: Mitigating Nitrogen Loss to the Environment

2016 INI, Crop management to improve nitrogen efficiency, Impact Presentation

Bryan G. Hopkins¹

¹Brigham Young University, 5115 LSB, Provo, Utah, 84602, http://lifesciences.byu.edu/~BRYANGH, hopkins@byu.edu

Abstract

Fertile soil is the foundation for food production and successful civilizations and is developed and maintained through the addition of nutrients lost through harvest. Nitrogen (N) accounts for approximately half of global fertilizer inputs. However, N recovery by plants is inherently inefficient with uptake of applied fertilizer N less than most other nutrients. Losses from the soil system can cause negative air and water resource impacts. Additionally, poor fertilizer efficiency is a waste of natural resources and potentially reduces yields, crop quality, and grower profits. Nitrogen-use efficiency (NUE) is increased through using optimal source, rate, timing, and placement. Polymer coated urea (PCU) is a source of N fertilizer that, when correctly managed, can result in virtually no N loss beyond background levels. A summary of our laboratory, glasshouse, and field research trials shows significantly less N loss from soil to the air and water due to dramatic increases in NUE from PCU compared to uncoated urea. Average ammonia volatilization and nitrous oxide emissions were lower for PUC by 300 and 120%, respectively. Residual nitrate was 38% lower for PCU compared to uncoated urea. The N losses for PCU fertilized plants were at or nearly the same as background levels for the controls. In all cases, PCU resulted in crop yields and/or quality which were significantly improved or at least equivalent to uncoated urea when managed properly. The global use of PCU is warranted to greatly improve environmental quality and to meet the demands for providing food, fuel, and fiber for the seven billion plus people on earth.

Dynamics of nitrate accumulation in soil as a function of inorganic and organic fertilization

2016 INI, Crop management to improve nitrogen efficiency, Impact Presentation

Attila Dunai, Zoltan Toth

University of Pannonia Georgikon Faculty, 16 Deak Ferenc Str, Keszthely, Hungary, H-8360, www.georgikon.hu, dunai@georgikon.hu

Abstract

The study was carried out in a long-tem field experiment set up in 1983 at the experimental site of the University of Pannonia Georgikon Faculty, Keszthely, Hungary. The experimental factors were the increasing rates of mineral N fertilizer and the complementary applied organic fertilizers (NPK: inorganic fertiilizers only, NPK + FYM: inorganic fertilizers and farmyard manure, NPK + St + GM: inorganic fertilizers, straw and green manure ploughed-in). Soil was a Ramann-type brown forest soil (Eutric Cambisol), with low humus content. The annual precipitation of the year of study was relatively high (877,1 mm).The amount of precipitation in the studied period (May-September 2014) was also high (557,1 mm).

Sampling of nitrate was carried out in the 0-1 m soli layer in 5 sublayers (0-20, 20-40, 40-60, 60-80, 80-100 cm) and in ten different dates during the growing season of corn in 2014.

The results show limited nitrate leaching in the first half of the growing season until a depth of 60 cm. No leaching of NO₃^–was measured in the deep soil layers below 60 cm. By the end of growing season soil became exhausted due to the nitrate absorption of the crop. Additional applied organic fertilizers resulted in higher nitrate values in the 0-60 cm soil layer at the first sampling date compared to the NPK plots, but these values reduced by the end of season without leaching.

Improving nitrogen use efficiency of irrigated rice (Oryza sativa L.): use of Stabilized Urea

2016 INI, Crop management to improve nitrogen efficiency, Impact Presentation

Kumara H.G.J.T.¹, Nissanka S.P¹, Gunawardane M², Abeysiriwardane D. S. De Z.³

¹Department of Crop Science, Faculty of Agriculture, University of Peradeniya, Peradeniya, Sri Lanka. spnissanka@gmail.com

²SLINTEC, Nanotechnology and Science Park, Mahenwatte, Pitipana, Homagama, Sri Lanka

³CIC Agri Businesses (Pvt) Ltd, Pelwehera, Dambulla, Sri Lanka

Abstract

Agronomic efficiency of N (AE_N) in rice cultivation ranges from 20-40 % due to heavy losses of applied N. Dicyandiamide (DCD) and N-(n-butyl) thiophosphorictriamide (NBPT) are used for some crops to enhance the efficiency of urea fertilizer and reduce ammonia volatilization, respectively. The DCD and NBPT were evaluated in combination with different levels of the recommended rate of urea by the Department of Agriculture (DOA), Sri Lanka to examine the (AE_N) in irrigated rice (Oryza sativa L.), conducting a pot experiment. As treatments, three levels of urea (100 % (225 kg Urea/ha), 75 % and 50 % of the DOA recommended rate) in the form of urea, and inhibitor compound with four levels (no compound, only NBPT, only DCD and combination of NBPT + DCD) and a control of no urea applied, were arranged in a Completely Randomized Design (CRD) with three replicates. The DCD and NBPT rates were 10 % and 1 % of the amount of urea used, respectively. Results showed that 50 % urea with inhibitors had no significant yield reduction (P>0.05) compared to 100 % urea alone, with a greater AE_N. Thus, application of urea with DCD and NBPT lead to a significant reduction in amount of urea application.

Stability of urease inhibitor added to urea

2016 INI, Crop management to improve nitrogen efficiency, Impact Presentation

Heitor Cantarella¹, Johnny R. Soares¹, Rafael M. Sousa¹, Rafael Otto², Cleiton Sequeira³

¹Agronomic Institute of Campinas, Av. Barão de Itapura 1487, Campinas, SP, 13020-902 Brazil, Email: cantarella@iac.sp.gov.br
² ESALQ-University of São Paulo, Av. Padua Dias, 11, Piracicaba, SP, 13418-900 Brazil.
³ Koch Agronomic Services, 4111 E. 37th St. N, Wichita, KS 67220, USA.

Abstract

The urease inhibitor N-(n-butyl thiophosphoric acid triamide) (NBPT) is being used to reduce ammonia (NH₃) volatilization losses of surface-applied urea but its shelf life is an issue. Urea treated with NBPT was stored for up to one year at two locations in Brazil: Paranaguá, PR (25°30’S and 48°30’W) and Rondonópolis, MT (16°26’ S and 54°49’ W). Treated urea samples were collected for the determination of NBPT concentration and for NH₃ volatilization from a Latosol under laboratory conditions. Ammonia losses from untreated urea varied from 32 to 48% of applied nitrogen (N); the corresponding values for freshly NBPT-treated urea varied from 8 to 26% of applied N. For fertilizer stored up to 6 months, NH₃ losses from untreated urea were significantly higher than those of urea containing NBPT, with no difference found among NBPT treated urea samples regardless of storage site and bag size. After 6 months, volatilization losses of NBPT treated samples stored in Rondonópolis were higher than those from Paranaguá. When samples were stored for 9 months, NH₃ losses for Paranaguá samples and freshly NBPT-treated urea were about 15% of applied N, while for Rondonópolis samples, losses were about 30% of applied N. Losses for untreated urea were about 45% of applied N. After 1 year, Paranaguá samples were still performing the same as freshly NBPT-treated urea. The degree of degradation of NBPT on urea stored under conditions similar to those of Paranaguá grants a shelf-life longer than those stored under hotter conditions similar to Rondonópolis.

Nitrogen use efficiency, crop productivity and environmental impacts of urea deep placement in lowland rice fields

2016 INI, Biological N fixation and cropping systems, Impact Presentation

Yam Kanta Gaihre ¹, Upendra Singh¹, Azmul Huda², S.M. Mofijul Islam³, M. Rafiqul Islam², Jatish Chandra Biswas³, Josh DeWald¹

¹International Fertilizer Development Center (IFDC), Muscle Shoals, 35622 USA (ygaihre@ifdc.org)

² Bangladesh Agricultural University (BAU), Mymensingh, Bangladesh

³ Bangladesh Rice Research Institute (BRRI), Gazipur, Bangladesh

Abstract

Nitrogen (N) fertilization is critical for cereal production; however, its low use efficiency poses both economic and environmental concerns. Urea deep placement (UDP) in lowland rice fields is one of the best currently applicable management techniques to increase N use efficiency (NUE) and crop productivity. Multi-location experiments conducted in Bangladesh in 2014-2015 have demonstrated several benefits of UDP use including reduced N losses through ammonia volatilization and greenhouse gas nitrous oxide (N₂O) and nitric oxide (NO) emissions. Nitrogen loss as N₂O and NO emissions were measured continuously throughout rice-growing and fallow seasons using an automated gas sampling and analysis system. Across the years and sites, UDP increased yield on average by 21% as compared to broadcast urea while using at least 25% less fertilizer. UDP reduced floodwater ammonium and ammonia volatilization similar to the control (N0) treatment, while both were significantly higher in broadcast urea treatments. UDP reduced N₂O emissions by up to 80% as compared to broadcast urea under continuous flooded (CF) conditions. The effects of UDP on N₂O emissions under alternate wetting and drying (AWD) irrigation practices were site specific: depending on the duration and intensity of soil drying, emissions were reduced under mild soil drying but increased with more intense soil drying. These results confirm that UDP not only increases NUE and grain yields but also reduces negative environmental impacts including N₂O emissions.