Archive for the category: Plenary

David J Pannell

University of Western Australia, david.pannell@uwa.edu.au, www.davidpannell.net

Abstract

The economics of nitrogen in farming systems are complex, multifaceted, fascinating and sometimes surprising. Economic insights are crucial for making sound decisions about farm-level management of nitrogen, and also about regional or national policy, such as for water pollution. In this paper I present key insights from a large and diverse literature. Issues covered include: the economics of nitrogen as an input to production; nitrogen and economic risk at the farm level; the economics of nitrogen fixation by legumes; the existence of flat payoff functions, which often allow wide flexibility in decisions about nitrogen fertilizer rates; explanations for over application of nitrogen fertilizers by some farmers; and the economics of nitrogen pollution, at both the farm-level and the policy level.

Insights, evidence and principles from economics are of central relevance to management, policy and research related to nitrogen. Important results that have been known to economists for decades, such as flat payoff functions, remain unknown to most agronomists and scientists. Accounting for these economic issues has the potential to substantially increase the benefits to farmers and to society as a whole.

Key words

Economics, policy, optimisation, profit, risk, pollution

James N. Galloway¹, Allison M. Leach², Jan Willem Erisman³ and Albert Bleeker⁴

¹Department of Environmental Sciences, University of Virginia, 291 McCormick Rd, Charlottesville, VA 22904, USA, jng@virginia.edu

²Department of Natural Resources and the Environment, University of New Hampshire, Durham, New Hampshire 03824, USA.

³Louis Bolk Institute, Hoofdstraat 24, 3972 LA Driebergen, The Netherlands Department of Earth Sciences, Earth and Climate cluster, VU University Amsterdam, Amsterdam, The Netherlands

⁴Department of Water, Agriculture and Food, The Netherlands Environmental Assessment Agency, Bezuidenhoutseweg 30, The Hague, The Netherlands.

 Abstract

Once upon a time there was enough naturally occurring nitrogen (N) to provide food for the world’s peoples.  Then there was not in the western regions.  Now there is due to the Haber-Bosch process.  But this transition from plenty, to scarcity, to plenty has come with a tremendous environmental cost.   The first step in actual knowledge attainment for N, was its discovery in 1772.  Basic and applied knowledge about N has been accumulating ever since.  We now know what needs to be done to maximize the benefits of N (feeding the world) while minimizing its impacts (the nitrogen cascade).  On the food production side, we know how to increase nitrogen use efficiency and decrease food waste. The challenge is to get this information to producers together with the mechanisms to implement the needed changes.  On the food consumption side, people have it in their power to stabilize the amount of N needed to grow food at current levels by eating to nutritional guidelines for protein.  The challenge is to educate those involved in food production and consumption.

<For the full paper, please contact James Galloway; jng@virginia.edu>

Cargele Masso, Peter Ebanyat, Fredrick Baijukya, Mateete Bekunda, Sifi Bouaziz, John Wendt, Bernard Vanlauwe

Abstract

One of the definitions for food security is having sufficient, safe, and nutritious food to meet dietary needs. There is an overdue need to optimize nitrogen use for food and nutrition security in developing countries particularly in sub-Saharan Africa, while minimizing environmental risks. In the past, nitrogen related environmental issues have often been associated with excessive use; however, of recently, challenges related to ‘too little’ nitrogen use has been recognized. In sub-Saharan Africa, nitrogen management must address the ‘too little’ and ‘too much’ paradox. Too little nitrogen is used in food production, which has led to chronic food insecurity and malnutrition. Conversely, too much nitrogen load in water bodies due mainly to excessive soil erosion, leaching, limited nitrogen recovery from wastewater, and atmospheric deposition still contributes to eutrophication in some areas. Significant research has been conducted to improve N use for food production, whereas little has been done to effectively address the ‘too much’ issues. The current research gaps must be addressed, and supportive policies operationalized, to maximize on nitrogen benefits, while reducing its negative impacts on the environment. Innovation platforms involving key stakeholders are required to address the nitrogen use efficiency along the full food supply chain in sub-Saharan Africa, as well as other World regions with similar challenges.

Wilfried Winiwarter¹

¹ IIASA, Schlossplatz 1, A-2361 Laxenburg, Austria, www.iiasa.ac.at, winiwarter@iiasa.ac.at

Abstract

Reactive nitrogen compounds, released by anthropogenic activities, may take different pathways in the environment, not all of which are easily traceable. Nitrogen budgets allow using surrogate information for fluxes that otherwise cannot easily be measured or validation of flux quantities for which an independent second set of data can be made available. In order to reliably assess nitrogen budgets and to make them comparable, the harmonization of approaches is required. Such a harmonizing effort has been performed under the European “air quality” convention, the Convention on Long-Range Transboundary Air Pollution. Based on existing efforts to collect data on fluxes of nitrogen compounds, specifically in the framework of the convention, from national greenhouse gas inventories mandatory under UNFCCC, or in connection with European activities of EUROSTAT or OECD, a guidance document has been developed to allow assessing national nitrogen budgets. Eight individual “pools” have been identified that are considered the start- and endpoints of environmental fluxes. The guidance document allows fluxes between pools to be properly assigned and quantified and provides a framework for consistent nomenclature. This paper shows complete and partial applications of the concept, and demonstrates the advantages of harmonizing approaches. It takes available published budgets for several European and non-European countries, analyzes them for compatibility, and evaluates nitrogen budgets for their potential contribution to a sustainable development of agriculture and beyond agriculture. From the few available examples is can be shown that nitrogen budgets allow to identify missing information as well as to define areas of intervention into the nitrogen regime. Comparing over time shows trends, e.g. as a result of environmental legislation, comparing between countries displays national characteristics useful for benchmarking. Linking towards specific abatement, nitrogen budgets may help in attaining “planetary boundaries” for nitrogen.

Michael Bell¹, Britta Schaffelke², Philip Moody³, David Waters⁴ and Mark Silburn⁴

¹ School of Agriculture and Food Science, University of Queensland, Gatton, Qld 4343, Australia. m.bell4@uq.edu.au

²Australian Institute of Marine Science, Townsville Qld 4810, Australia, b.schaffelke@aims.gov.au

³ Landscape Sciences, Department of Science, Information Technology and Innovation, Dutton Park Qld 4102, Australia, phil.moody@dsiti.qld.gov.au

⁴ Department of Natural Resources and Mines (DNRM), Toowoomba Qld 4350 Australia david.waters@dnrm.qld.gov.au Mark.silburn@dnrm.qld.gov.au

Abstract

The water discharged from rivers draining into the Great Barrier Reef (GBR) lagoon carries land-derived suspended sediments, nutrients and pesticides. Total nitrogen (N) loads have more than doubled since development, with the extensive grazing and intensive sugarcane industries the largest contributors. Runoff and soil erosion are the main sources of riverine particulate nitrogen (PN) while fertilizer application has contributed to the increase in dissolved inorganic nitrogen (DIN). Dissolved organic N (DON) loads have increased less and it is unclear if DON has changed with development. DIN is rapidly taken up by marine plants and cycled through the marine food web, resulting in typically low concentrations of DIN in GBR waters, and an N-pool dominated by DON and PN of marine origin. The productivity of marine plants is sustained by rapid recycling of organic nutrients. Additional available N, as occurs from land runoff, can result in adverse effects on coral reefs by increasing coral vulnerability to temperature stress, and by benefitting coral competitors and predators.

Ambitious targets to reduce N loads from key catchments have been set and a combination of changes to land use and nutrient management practices will be required to achieve the necessary water quality improvement. Prioritization of actions that maximize water quality benefits will require new fertilizer technology for cropping industries and greater certainty around underlying processes contributing to bioavailable N loads from all land uses. Uncertainties include the relative importance of DIN compared to total bioavailable N, and of the contribution of runoff compared to other N loss pathways like subsurface lateral flow and deep drainage.

Xiaoyuan Yan¹, Xuejun Liu²

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

^{2 College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China}

Abstract

China now creates more Nitrogen (N) than any other country in the world. Total N input to the terrestrial ecosystem of mainland China increased from 25.2 Tg in 1980 to 61.0 Tg in 2010, while the amount of natural N₂ fixation changed little during this period (9.3–11.0 Tg). Though large amount of N input plays a vital role in ensuring food security, it has contributed to low nitrogen use efficiency in crop production systems. Much of the remainder N can be considered an expensive and environmentally damaging waste such as emissions of greenhouse gases, degradation of soil and freshwater. Average bulk N deposition, plant foliar N and crop N uptake from long-term unfertilized croplands all significantly (p<0.05) increased from 1980 to 2010, in agreement with rapidly increased NH₃ and NOx emissions. As a consequence, significant soil acidification was reported in major Chinese croplands, grasslands and forestlands. Clear evidence showed that plant species richness and soil bacterial diversity declined with increased N deposition in temperate grasslands. Meanwhile, large amounts of soil nitrate N accumulation were observed in major upland soils in China, threatening groundwater quality. Surface water eutrophication, air quality deterioration, both closely linked with reactive N, are increasingly being witnessed. China is facing a huge challenge to realize food security and protect the environment through maximizing N use efficiency and minimizing N negative effects.