Global Nitrous Oxide Emissions: Sources and Opportunities for

Chapter 14

Downloaded by UNIV OF CALIFORNIA SAN DIEGO on February 4, 2016 | http://pubs.acs.org Publication Date (Web): October 11, 2011 | doi: 10.1021/bk-2011-1072.ch014

Global Nitrous Oxide Emissions: Sources and Opportunities for Mitigation R. M. Rees* Scottish Agricultural College Edinburgh, EH9 3JG, U.K. *E-mail: [email protected]

Global emissions of nitrous oxide (N2O) have risen steadily in recent years as a result of human activity. During the 1990s, total emissions were estimated to be 28 Tg N2O annually. Nitrous oxide is a powerful greenhouse gas and in addition is involved in the destruction of stratospheric ozone. Emissions are spatially uneven and are strongly dominated by sources from fertilised agricultural soils, both in the form of direct and indirect emissions. Soil conditions, particularly at the time of fertiliser application, are important in determining the magnitude and timing of emissions. The type of land use is also important, with a strong correlation between livestock farming and national emissions. Opportunities exist to reduce emissions of N2O by improving the efficiency of nitrogen (N) use in farming systems and the application of new management technologies. Such approaches are often popular with farmers given that they contribute to environmental and economic benefits. However, to achieve large emission reductions it is necessary to alter the nature of production systems, with particular attention being focussed on livestock production. This paper reviews the global anthropogenic sources of emission of N2O and considers options for mitigation at a regional scale.

Introduction Nitrous oxide (N2O) is a powerful greenhouse gas with a global warming potential of 296 times greater than that of CO2 (1). For this reason it is recognised © 2011 American Chemical Society In Understanding Greenhouse Gas Emissions from Agricultural Management; Guo, Lei, et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 2011.


that efforts to limit the accumulation of greenhouse gases in our atmosphere must include measures that reduce N2O emissions (2). Sources of N2O are diverse, but the dominant source is of terrestrial origin. Total global emissions during the 1990s were estimated by the IPCC’s Fourth Assessment Report to be 27.8 (13.4-43.5) Tg N2O per year (3). This report recognises that there is considerable uncertainty in some emission estimates of N2O and that less than half of the global N2O emissions are directly attributable to anthropogenic sources. However, anthropogenic sources have been primarily responsible for the growth in emissions over the past century, and they are most easily reduced through mitigation measures. The remainder of this chapter therefore discusses the nature and potential mitigation of anthropogenic N2O sources. The largest single anthropogenic source (27% of total global anthropogenic emissions) originates directly from soils mostly following fertiliser nitrogen applications and other land based sources can be linked to the management of nitrogen in agricultural systems (Figure 1). These include manures in pasture based systems (19%), indirect losses (9%), savanna burning 7% and indirect N2O from non agricultural NOx (6%), with total anthropogenic sources in 2005 contributing to 9.6 Tg N2O per year (4). Although the source processes that generate N2O are well understood (6–9), it remains difficult to predict emissions in the field given the strong interaction of environmental drivers that change the rates of emissions, often over short timescales and small spatial scales. A meta-analysis of research studies has shown that N2O emissions vary according to the amount, chemical form and timing of fertiliser nitrogen (N) applications, but soil conditions such as wetness, pH and drainage are also important (10).

Figure 1. Global anthropogenic sources of N2O partitioned by source. The other category covers a range of industrial and terrestrial sources including chemical production, transport, energy production and biomass burning (4, 5). 258 In Understanding Greenhouse Gas Emissions from Agricultural Management; Guo, Lei, et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 2011.


Figure 2. Growth rates in direct soil emissions of N2O compared against a 1970 baseline from selected countries between 1970-2005. (4, 5) The variability in emissions associated with environmental conditions and management activity provide considerable scope for mitigation of N2O emissions. It has been suggested that the application of improved management practices and better fertiliser management could reduce global emissions by 20% (11), and provide co-benefits of improved nutrient use efficiency, reduced leaching losses and increased profitability for farming enterprises. However, the realisation of this mitigation potential needs to take account of large regional differences in the sources of emissions and the technological and economic potential of countries to take action. During the past century, the use of nitrogen fertilisers has increased significantly in order to support growing human populations and their demand for food (12, 13). However, this growth has been very uneven over the past 30 years with high population growth in the developing regions of the world, linked to large increases in fertiliser use and associated N2O emissions. A comparison of emission inventories from different countries over the period between 1970-2005 illustrates that whilst N2O emissions in developed countries such as the UK and the US have been relatively stable, in developing regions such as China and India, emissions over the period increased by between three to four times (Figure 2). The growth in fertiliser use and associated N2O emissions are predicted to continue with continuing regional variability (14). Regional differences in emissions of N2O from agriculture can be described in terms of the amount per region and also the way in which that amount is partitioned by source. At the global scale, Asia is the dominant source of N2O contributing to over 45% of anthropogenic emissions (Figure 3). This is greater than the combined emissions of Africa, South and Central America, and Europe 259 In Understanding Greenhouse Gas Emissions from Agricultural Management; Guo, Lei, et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 2011.


and Oceana, reflecting the large human population in this region and their consumption of fertiliser nitrogen to support food production. It should also be noted that there are significant differences in partitioning of sources of N2O between regions. Thus in Europe, Asia, North America, and Central and South America, direct emissions from soils make up over 50% of total emissions. This reflects the importance of emissions from crop growth in these areas. In Africa and Oceana by contrast emissions from manure and pasture management are dominant. Both the amount and intensity of fertiliser use also vary significantly by region (Table 1). Highest intensities of N use (between 26-24 kg N/ha) are located in Europe, North America and Asia, however, these values represent average N applications per unit area of agricultural land, and hide significant variability. Much lower rates of fertiliser N are applied to regions of the world that include extensive (often unfertilised) grassland or rangeland landscapes in Africa, Latin America and Oceana. The larger land area and higher fertiliser use in Asia result in the largest regional N2O emission of 2451 Gg/year (Table 2). But the larger population of Asia contributes to the lowest global emission (623 g N2O/person/year) when expressed on a per capita basis. This compares with emissions in Latin America and North America of 1521 and 2167 g N2O/person/year, respectively. The projected population growth to 9 billion by the middle part of the century (UN median projections) can be used to predict N2O emissions by 2050 assuming a constant per capita emission. The projections would indicate very large increases in emissions in Africa and Asia, but falling emissions across Europe.

Figure 3. Global N2O emissions from agriculture divided by continent and partitioned by source. The size of the pies is proportional to the annual emission in 2005 (4, 5).

260 In Understanding Greenhouse Gas Emissions from Agricultural Management; Guo, Lei, et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 2011.


Table 1. Fertiliser use and land areas in different regions of the world for 2005 (15) Mean N application to agricultural area kg N/ha

Region1

Fertiliser N use (Mt N)

Total Area (000 k ha)

Agricultural Area (000 k ha)

Africa

3.1

30312

1151

2.7

Asia

55.1

31967

1640

33.6

Europe

13.0

2300

472

27.5

Latin America and Caribbean

5.8

2052

713

8.2

N America

12.8

2002

480

26.6

Oceana

1.3

856

459

2.8

Table 2. Regional anthropogenic N2O emissions per capita emissions and projected growth rates (5, 15) Population

Current N2O emission (Gg)

Current per capita emission of N2O (g)

Projected population growth 2000-2050

Projected N2O emission 2050 (Gg)

Africa

921073

592

643

2.44

1444

Asia

3936536

2451

623

1.41

3467

Europe

729421

570

781

0.95

542

Latin America & Caribbean

556512

846

1521

1.40

1184

N America

335175

726

2167

1.41

1022

At the global level, the production of N2O emissions is closely linked to meat production (Figure 4) and this helps to explain the high per capita emissions on the American continent where meat production is highest. Such observations have been previously reported (16–18), but the relationship is important when considering future trends in emissions and potential for mitigation. As illustrated above, emissions of N2O are already dominated by Asia, where per capita meat consumption is relatively low when compared to that of regions such as Europe and North America. It is widely assumed that as the populations of Asia become more affluent, consumption of meat and dairy products will increase. Such a change would almost inevitably increase N2O emissions from this region still further.



Figure 4. The relationship between direct soil emissions of N2O and meat production (5, 15). The accounting system used to assign emissions to individual regions has weaknesses when used to consider mitigation potential on a regional basis. Emissions are assigned to the country in which agricultural products are produced. However, the global trade in agricultural products generates major flows of commodities between regions. For example, livestock feed consumed in North America and Europe is produced in large quantities in South America, with an annual transfer of N in grain of 2.4 Mt (19). Despite these inadequacies, the link between N2O emission and livestock production is well-established, and it is likely that the projected increase in the consumption in Asia is inconsistent with attempts to reduce N2O emissions in the coming decades.

Mitigation The opportunities for mitigation of N2O emissions from agriculture will vary according to region as a consequence of large differences in methods of production within farming systems, and in both technology and resources available for the application of mitigation measures. The potential for mitigation will also vary, being large in circumstances where high levels of fertiliser N are applied to highly organic soils, but much lower when N inputs are low and other soil conditions constrain emissions. A wide range of mitigation measures have been proposed, each associated with varying mitigation potentials (Table 3). It is widely recognised that those options that improve the efficiency of resource use within agriculture are most likely to be adopted as a priority, since they bring the co-benefits of economic gain and wider environmental benefits (49). Beyond improvements in efficiency, there are a range of technical and management 262 In Understanding Greenhouse Gas Emissions from Agricultural Management; Guo, Lei, et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 2011.


changes that can be used to reduce N2O emissions such as the replacement of nitrogen fertilisers by biologically fixed N from legumes within farming systems (50, 51), the use of nitrification inhibitors (40), drainage (52) and improved soil conditions (38, 53). Such approaches are likely to deliver modest reductions in emissions of between 10-20%. Greater emission reductions are likely to be possible only through more significant land use change, involving a switch to systems with lower inputs of fixed nitrogen and reductions in some areas of livestock production. The benefits of such changes would however vary on a regional basis. Food Supply Increases in the global population are driving a rapid increase in demand for food. With the global population predicted to peak at around 9 billion by the middle part of this century, demand is currently rising steeply. At the same time, the increasing affluence of the world’s population is resulting in the demand for higher value products associated with higher greenhouse gas emissions (e.g. meat and dairy products). However, agriculture is also facing constraints generated by the limited availability of land, limited resources (such as oil and phosphorus), limited water availability, declining biodiversity and climate change. These factors combined contribute to what has been described as “the perfect storm” for agriculture (54). One of the key messages from this analysis is that future methods of food production need to rely on more sustainable approaches to the management of resources, and in particular, there is a need to produce food with significantly lower greenhouse gas emissions. It has been argued that one approach to this problem would be to develop the concept of sustainable intensification (54). This would be achieved by dramatic increases in the efficiency with which resources in agriculture are used enabling production to be maintained or increased whilst resource inputs decline. In theory there is plenty of scope for improvement. It has been found that only 14% of the N fixed by the Harber-Bosch process is consumed by humans with a vegetarian diet. This falls to 4% for a carnivorous diet (12). Costs The costs of different mitigation options vary significantly. This variability is associated both with the magnitude of intervention involved, and the location in which it takes place. Thus alteration in the timing of fertiliser nitrogen applications or improved adherence to fertiliser recommendations may involve little or no cost to a farmer and could even contribute to improvements in productivity. Such measures are always likely to be the easiest to introduce and contribute quickly to reductions in greenhouse gas emissions. More significant savings in emissions may require interventions involving a greater change in methods of production, or greater cost. For example improved drainage has been shown in many circumstances to reduce N2O emissions following addition of fertiliser nitrogen. However, such activities can be highly expensive and are often justified only where increases in crop yield can be demonstrated. The 263 In Understanding Greenhouse Gas Emissions from Agricultural Management; Guo, Lei, et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 2011.


relationship between the cost of a mitigation measure and greenhouse gas savings, can be represented by preparing a marginal abatement cost curve. Recent work in the UK has shown that a large amount of greenhouse gas mitigation can be achieved by applying measures that deliver both financial savings and reductions in greenhouse gas emissions; so called win-win measures (49). The analysis takes into account both the cost of the measure and the costs of impacts associated with it (e.g., changes in the value of agricultural products). This work implies that improvements in efficiency can make an important contribution to reducing greenhouse gas emissions from the agricultural sector. The approach is also valuable in identifying a logical order in which mitigation activities should be implemented. However, it can be difficult to assess the importance of individual mitigation measures on greenhouse gas balances, particularly at larger regional scales. It is also difficult to determine how individual measures will interact when used in combination (55). It could be envisaged that a farm enterprise aiming to reduce its greenhouse gas emissions would implement several measures simultaneously. However, once each measure has been introduced the potential to mitigation by the introduction of further measures becomes less, and the potential costs increase. A further difficulty relates to spatial heterogeneity. At a national scale, if a government wishes to reduce emissions of greenhouse gases, it may be more appropriate to target emission hotspots rather than attempt to introduce blanket measures that could involve significant cost and yet relatively low mitigation. However, within hotspots, more significant intervention could achieve a high level of mitigation and remain cost-effective at the national scale. There is also likely to be variation in the costs of measures in different regions. Thus where labour costs are low, such as in many developing countries, activities involving additional labour (cultivation or increasing numbers of fertiliser applications) may result in higher greenhouse gas savings per unit cost than elsewhere.

Table 3. The range of potential N2O mitigation achieved by the use of different measures Category

Measure

Mitigation potential (% reduction in business as usual)

Reference

Agronomy

Crop mixtures and intercrops

0-20

(20)

More efficient crop varieties

0-20

(21)

Improved management of crop residues

10-30

(22–25)

Continued on next page.


Table 3. (Continued). The range of potential N2O mitigation achieved by the use of different measures


Category

Soil Management

Fertiliser Management

Land use change

Measure

Mitigation potential (% reduction in business as usual)

Reference

Use of legumes to provide N input

20-40

(26)

Improved irrigation scheduling

0-20

(27, 28)

Minimum tillage

-20-+10

(29–32)

Improved drainage

0-20

(33–35)

pH management

0-20

(36)

Improved soil structural conditions

0-20

(37, 38)

Use of urea in place of ammonium nitrate

0-10

(39)

Nitrification inhibitors

20-80

(40–42)

Reduced fertiliser application

10-80

(43, 44)

Improved timing

0-10

(43, 45)

Precision application of fertilisers

10-20

(11)

Improved management of manures and composts

10-20

(46)

Grassland to cropland

10-40

(47)

Grassland to agro-forestry

20-40

(48)

Cropland to agro-forestry

20-40

(48)


Regional Potential for Mitigation


Europe Both total (570 Gg/year) and per capita (781g/person/year) emissions of N2O in Europe are not high by global standards. However, fertiliser nitrogen application rates in Europe are relatively high when compared with global averages. Agricultural systems are generally dependent upon high levels of technical support and sophisticated advisory and development systems. Over the past decade, rates of fertiliser nitrogen application have declined in response to high fertiliser costs, environmental regulation and attempts to reduce greenhouse gas emissions, but reducing emissions of N2O remains a high priority for many European countries. A recent analysis of the greenhouse gas balance in Europe identified N2O as being of particular importance (2). Emissions of N2O and CH4 from land based sources in Europe effectively cancels out the carbon sequestration capacity of forests and grasslands maintaining a near neutral greenhouse gas balance. However, future intensification in the region could easily lead to the continent becoming a net source as a result of non-CO2 greenhouse gas emissions (2). Nitrogen use in Europe is also influenced by European agricultural support policies. Over the past decade the nitrates directive has encouraged more efficient use and lower levels of nitrogen application to farmland in order to reduce nitrate leaching within catchments. The high levels of nitrogen use, and sophisticated support mechanisms provide the opportunity for further reductions in N2O emissions through a range of measures. In the first instance increasing efficiency is likely to provide an opportunity for reductions in N2O emissions, leading to 20 to 40% reduction in some circumstances (55). Larger emission reductions are likely to be possible through land use change. However, Europe also has the opportunity for technical intervention within agricultural systems that are not possible elsewhere due to the high levels of technical capability. Thus the use of nitrification inhibitors, precision farming, and the development of new crop varieties can contribute to significant further reductions in emissions although often that higher cost. Asia Asia dominates emissions of N2O at the global level, however, per capita emissions are the lowest in any region (623 g/person/year). Asia currently emits 2451 Gg N2O/year or 46 % of the global anthropogenic total, and so is hugely important in determining the magnitude of global emissions. In 2005 Asia used 55 Mt N which was equivalent to 60% of the global total. The observation that the proportion of global N2O emissions is so much lower that the proportion of fertiliser use could be seen as an indicator of efficiency, and is explained by the lower consumption of meat based food products in this region. Emissions in India and China are rising rapidly in response to fertiliser applications to support increasing food production. Emissions are largely associated with direct losses from soils, indicating the importance of losses from fertiliser nitrogen application to crops. A recent modelling exercise explored the distribution of N2O emissions in China, and found a highly variable distribution, which was explained 266 In Understanding Greenhouse Gas Emissions from Agricultural Management; Guo, Lei, et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 2011.


by the density of cropping and fertiliser use (56). A regional modelling study indicated that China’s grasslands also make an important contribution of around 77 Gg N2O/year to national emissions (57). The larger fertiliser applications and warmer summers in central and south eastern China were associated with highest emissions, and this is an area in which mitigation measures would be most effective. Indian N2O emissions also show a wide variability, and were similarly related to the distribution of N inputs (58). Investment in agricultural support systems in these regions is relatively low, providing significant opportunities for increased fertiliser use efficiency based upon improved advice and consultancy (59). This would include recommendations that enable crop demand for nitrogen to be more accurately matched to fertiliser supply. Extension services could also provide recommendations on improved agronomy and soil science. Africa Africa has relatively low emissions of N2O (592 Gg in 2005) and low per capita emissions (643g/person/year). There is a scarcity of data describing emissions in response to agricultural management across the continent (60), however, they are low when compared to those in other regions. This could be because of high levels of infertility within soils, low rainfall across large regions of the continent, and low fertiliser application rates. Studies in Zimbabwe have reported relatively low emissions of 3.4 µg N2O-N m-2 h-1 from croplands, but observed much higher emissions (30.5 µg N2O-N m-2 h-1 ) from cleared woodlands (61). Reviews of other studies have also indicated that low emissions are widespread across the African continent (62). Extension services in this region are relatively poor, providing an opportunity for investment targeted at increasing efficiency of fertiliser use. Chronic malnutrition and hunger across the region also place urgent demands upon extension services to increase agricultural productivity in order to achieve higher levels of food production across the continent. There is an urgent need to address these problems through integrated nutrient management which includes developing an appropriate balance of organic and inorganic nutrient inputs that avoid the long term depletion of the soil nutrient capital (63, 64). North America Emissions of N2O from North America were 726 Gg N2O/year which translates into per capita emission of 2167 g N2O/year, the equivalent of 646 kg CO2/year. The land area in North America and the area under cultivation is large, but fertiliser application rates per unit area are lower than those in other developed regions such as Europe. Like Europe, North America has a well-developed extension service, and the high-tech agricultural industry. This provides opportunities for reducing N2O emission through increasing fertiliser use efficiency such as improving timing and rates of fertiliser applications, improving soil conditions, and agronomy (65). The application of high-tech solutions to fertiliser management such as the use of precision farming and 267 In Understanding Greenhouse Gas Emissions from Agricultural Management; Guo, Lei, et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 2011.


nitrification inhibitors also provide important opportunities in North America for reducing emissions. High levels of meat production and consumption contribute significantly to emissions in North America, and therefore significant emission reductions could be achieved by lowering levels of meat production across the continent. Snyder et al. (65) identified four areas that would assist in the minimisation of greenhouse gas emissions from US agriculture. These were general adherence to best agronomic practice, maintenance of application equipment, efficient crop management and system planning, and the use of urease and nitrification inhibitors. In a review of greenhouse gas mitigation practices (66) highlighted the importance of pollution swapping as a consequence of some measures. Thus for example reduced tillage and the incorporation of manures and slurry centre soils can contribute to increased carbon storage; however, this is often outweighed by increase in N2O emissions.

South and Central America Emissions of N2O in this region were 846 Gg/year, with per capita emissions of 1521 g N2O/year. These relatively large emissions reflect the importance of livestock production in the extensive rangeland ecosystems located across South America. No-till farming systems are thought to reduce net greenhouse gas emissions through increasing C sequestration, and are widely adopted in the South American pampas. However, a review of experiments has shown that increased N2O emissions resulting from no till offset the benefits of C sequestration (67). It is anticipated that population growth and the associated demand for food will lead to rapid growth in N2O emissions in the continent of South America (68). Land use change has historically been an important driver of greenhouse gas emissions on the South American continent, particularly in areas such as Brazil, where widespread deforestation has taken place in order to accommodate large areas of grain production. More recently sugarcane has replaced other crops in Brazil as being the most important in terms of area and income, reflecting the growing importance of bio-ethanol production as an output from agricultural systems. An understanding of the greenhouse gas emissions associated with biofuel production has become particularly important since it determines the extent to which such products can offset greenhouse gas emissions by fossil fuels. Thus the production of crops, such as sugarcane, grain crops, and oilseeds, is associated with greenhouse gas emissions mainly in the form of N2O emissions. When these emissions exceed those who would be associated with the combustion of an equivalent amount of fossil fuel, it is argued that such production has a negative environmental impact. Research has shown that production of biofuels in warmer tropical countries such as Brazil is associated with relatively high levels of efficiency, allowing them to contribute to a reduction in net greenhouse gas emissions (69).



Oceana Land area and agricultural production in Oceana are dominated by Australia and New Zealand, with a total N2O production of 183 Gg/year (the lowest in any region). It should be noted that this region also includes the Pacific islands of Melanesia and Polynesia and is therefore climatically highly diverse with large areas of desert and agricultural land with low productive potential. Parts of New Zealand and Australia include some areas of highly productive intensively managed agricultural land. Nitrous oxide emissions within the region therefore highly variable, and are often influenced strongly by cycles of wetting and drying in the more arid regions of Australia. Some recent studies have indicated that N2O emissions in these drier areas may be overestimated by the IPCC default emission factors (70). New Zealand’s agricultural economy is dominated by pasture based on livestock production. This combined with the fact that New Zealand has relatively scarce heavy industry has led to the agricultural sector being the main source of greenhouse gas emissions. New Zealand has therefore placed a high priority on the development of mitigation strategies that can be used to reduce greenhouse gas emissions for the agricultural sector. Recent studies have shown that N2O emissions can be produced from grazed grasslands by between 50 and 70% by use of nitrification inhibitors (40, 71, 72). These reductions in N2O emission were also associated with a reduction in other losses of nitrogen and increasing nitrogen use efficiency. This makes products such as nitrification inhibitors more attractive commercially particularly given the increasing cost of nitrogen fertilisers.

Conclusions The global growth in N2O emissions has been driven by an increase in the demand for agricultural produce and of meat and dairy products. There are many options available to producers that can reduce emissions on a unit area and unit product basis. In many circumstances, significant reductions in emissions can be achieved by increasing the efficiency of farming systems. Options include improvements in the timing and amounts of N fertilisers applied, careful management of soil conditions and the use of appropriate crops and crop rotations that match the prevailing environmental conditions. In some developed countries, this may involve reducing N inputs to agricultural systems by improving N fertiliser efficiency, but in some developing countries, increasing the amounts of N fertiliser may deliver lower emissions on a unit product basis. Minor changes to the management of agricultural systems as described above could be expected to deliver moderate reductions in N2O emissions, and would be linked to co-benefits in terms of improved economic performance and other environmental benefits. However, larger emission reductions would be likely to require more significant change in land use and production systems. In particular a switch away from the largely meat based diets that are prevalent in North America and Europe would result in significant additional savings. It is interesting to note that such demand led changes would not always be reflected in the national greenhouse gas budgets of countries where those changes occurred, 269 In Understanding Greenhouse Gas Emissions from Agricultural Management; Guo, Lei, et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 2011.

given that international trade results in widespread distortions of the link between greenhouse gas emissions and consumption of agricultural produce. However, as global societies seek ways of reducing greenhouse gas emissions, changes in the efficiency and nature of food production systems around the globe are likely to become hard to resist.

Acknowledgments Downloaded by UNIV OF CALIFORNIA SAN DIEGO on February 4, 2016 | http://pubs.acs.org Publication Date (Web): October 11, 2011 | doi: 10.1021/bk-2011-1072.ch014

Financial support for this work was provided by the Scottish Government.

References 1.

Solomon, S.; Qin, D.; Manning, M.; Chen, Z.; Marquis, M; Averyt, K. B.; Tignor, M.; Miller, H. L. IPCC: Climate Change 2007: The Physical Science Basis, Report of the Intergovernmental Panel on Climate Change (IPCC); Cambridge University Press: Cambridge, 2007. 2. Schulze, E. D.; Luyssaert, S.; Ciais, P.; Freibauer, A.; Janssens, E. A. Nat. Geosci. 2009, 2, 842–850. 3. Denman, K. L.; Brasseur, G.; Chidthaisong, A.; Ciais, P.; Cox, P. M.; Dickinson, R. E.; Hauglustaine, D.; Heinze, C.; Holland, E.; Jacob, D.; Lohmann, U.; Ramachandran, S.; da Silva Dias, P. L.; Wofsy, S. C.; Zhang, X. Couplings Between Changes in the Climate System and Biogeochemistry. In Climate Change 2007: The Physical Science Basis; Solomon, S.; Qin, D.; Manning, M.; Chen, Z.; Marquis, M.; Averyt, K. B.; Tignor, M.; Miller, H. L., Eds.; ; Cambridge University Press: Cambridge, U.K., 2007. 4. European Commission, Joint Research Centre (JRC)/Netherlands Environmental Assessment Agency (PBL), 2010. 5. Emission Database for Global Atmospheric Research (EDGAR), Version 4.1. URL http://edgar.jrc.ec.europe.eu. 6. Wrage, N.; Velthof, G. L.; van Beusichem, M. L.; Oenema, O. Soil Biol. Biochem. 2001, 33, 1723–1732. 7. Mosier, A. R. Plant Soil 2001, 228, 17–27. 8. Bateman, E. J.; Baggs, E. M. Biol. Fertil. Soils 2005, 41, 379–388. 9. Skiba, U.; Drewer, J.; Tang, Y. S.; van Dijk, N.; Helfter, C.; Nemitz, E.; Famulari, D.; Cape, J. N.; Jones, S. K.; Twigg, M.; Pihlatie, M.; Vesala, T.; Larsen, K. S.; Carter, M. S.; Ambus, P.; Ibrom, A.; Beier, C.; Hensen, A.; Frumau, A.; Erisman, J. W.; Brggemann, N.; Gasche, R.; Butterbach-Bahl, K.; Neftel, A.; Spirig, C.; Horvath, L.; Freibauer, A.; Cellier, P.; Laville, P.; Loubet, B.; Magliulo, E.; Bertolini, T.; Seufert, G.; Andersson, M.; Manca, G.; Laurila, T.; Aurela, M.; Lohila, A.; Zechmeister-Boltenstern, S.; Kitzler, B.; Schaufler, G.; Siemens, J.; Kindler, R.; Flechard, C.; Sutton, M. A. Agric., Ecosyst. Environ. 2009, 133, 139–149. 10. Bouwman, A. F.; Boumans, L. J. M.; Batjes, N. H. Global Biogeochem. Cycles 2002, 16, 1058–1070. 270 In Understanding Greenhouse Gas Emissions from Agricultural Management; Guo, Lei, et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 2011.


11. Mosier, A. R.; Duxbury, J. M.; Freney, J. R.; Heinemeyer, O.; Minami, K. Clim. Change 1998, 40, 7–38. 12. Galloway, J. N.; Cowling, E. B. Reactive nitrogen and the world: 200 years of change. Ambio 2002, 31, 64–71. 13. Erisman, J. W.; Sutton, M.; Galloway, J. N.; Klimont, Z.; Winiwarter, W. Nat. Geosci. 2008, 1, 636–639. 14. Tilman, D.; Fargione, J.; Wolff, B.; D’Antonio, C.; Dobson, A.; Howarth, R.; Schindler, D.; Schlesinger, W. H.; Simberloff, D.; Swackhamer, D. Science 2001, 292, 281–284. 15. Food and Agriculture Organization of the United Nations (FAO). FAOSTAT. URL: http://faostat.fao.org/ 16. Steinfeld, H.; Gerber, P.; Wassenaar, T.; Castel, V.; Rosales, M.; de Haan, C. Livestock’s Long Shadow; Environmental Issues and Options; Rome, Food and Agriculture Organization of the United Nations (FAO), 2006. 17. Galloway, J. N.; Burke , M.; Bradford, G. E.; Naylor, R.; Falcon, W.; Chapagain, A. K.; Gaskell, J. C.; McCullough, E.; Mooney, H. A.; Oleson, K. L. L.; Steinfeld, H.; Wassenaar, T.; Smil, V. Ambio 2007, 36, 622–629. 18. Garnett, T. Environ. Sci. Policy 2009, 12, 491–503. 19. Galloway, J. N.; Townsend, A. R.; Erisman, J. W.; Bekunda, M.; Cai, Z. C.; Freney, J. R.; Martinelli, L. A.; Seitzinger, S. P.; Sutton, M. A. Science 2008, 320, 889–892. 20. Pappa, V. A.; Rees, R. M.; Walker, R. L.; Baddeley, J. A.; Watson, C. A. Effects of intercrops in a three year low input rotation. Climate, Water and Soil: Science, Policy and Practice; Crichton, K., Audsley, R., Eds.; SAC/ SEPA: Edinburgh, 2010; pp 153−159. 21. Cassman, K. G.; Dobermann, A .; Walters, D. T. Ambio 2002, 31, 132–140. 22. Aulakh, M. S.; Khera, T. S.; Doran, J. W.; Bronson, K. F. Biol. Fertil. Soils 2001, 34, 375–389. 23. Promsakha, S.; Sakonnakhon, N.; Toomsan, B.; Cadisch, G.; Baggs, E. M.; Vityakon, P.; Limpinuntana, V.; Jogloy, S.; Patanothai, A. Plant Soil 2005, 272, 183–199. 24. Baggs, E. M.; Chebii, J; Ndufa, J. K. Soil Tillage Res. 2006, 90, 69–76. 25. Ciarlo, E. A.; Llorente, M. M.; Conti, M. E.; Giardina, E. B. Commun. Soil Sci. Plant Anal. 2009, 40, 2756–2772. 26. Soussana, J. F.; Allard, V.; Ambus, P.; Berbigier, P.; Campbell, C.; Cellier, P.; Ceschia, E. Sources and sinks of greenhouse gases from European grasslands and mitigation options; XX International Garssland Congress: Dublin, Ireland, 2005; p 564. 27. Vallejo, A.; Diez, J. A.; Lopez-Valdivia, L. M.; Cartagena, M. C.; Tarquis, A.; Hernaiz, P. Biol. Fertil. Soils 2004, 40, 93–100. 28. Sanchez-Martin, L.; Meijide, A.; Garcia-Torres, L.; Vallejo, A. Agric., Ecosyst. Environ. 2010, 137, 99–107. 29. Skiba, U.; van Dijk, S.; Ball, B. C. Soil Use Manage. 2002, 18, 340–345. 30. Elder, J. W.; Lal, R. Tillage effects on gaseous emissions from an intensively farmed organic soil in North Central Ohio. Soil Tillage Res. 2008, 98, 45–55. 271 In Understanding Greenhouse Gas Emissions from Agricultural Management; Guo, Lei, et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 2011.


31. Halvorson, A. D.; Del Grosso, S. J.; Reule, C. A. J. Environ. Qual. 2008, 37, 1337–1344. 32. Rochette, P. Soil Tillage Res. 2008, 101, 97–100. 33. Rees, R. M.; Wuta, M.; Furley, P. A.; Li, C. S. J. Biogeogr. 2006, 33, 424–437. 34. Dobbie, K. E.; Smith, K. A. Soil Use Manage. 2006, 22, 22–28. 35. Goldberg, S. D.; Knorr, K. H.; Blodau, C.; Lischeid, G.; Gebauer, G. Global Change Biol. 2010, 16, 220–233. 36. Mosier, A. R.; Delgado, J. A.; Keller, M. Methane and nitrous oxide fluxes in an acid Oxisol in western Puerto Rico: Effects of tillage, liming and fertilization. Soil Biol. Biochem. 1998, 30, 2087–2098. 37. Smith, K. A.; McTaggart, I. P.; Tsuruta, H. Soil Use Manage. 1997, 13, 296–304. 38. Ball, B. C.; Scott, A.; Parker, J. P. Soil Tillage Res. 1999, 53, 29–39. 39. Venterea, R. T.; Dolan, M. S.; Ochsner, T. E. Soil Sci. Soc. Am. J. 2010, 74, 407–418. 40. Di, H. J.; Cameron, K. C.; Sherlock, R. R. Soil Use Manage. 2007, 23, 1–9. 41. Fangueiro, D.; Fernandes, A.; Coutinho, J.; Moreira, N.; Trindade, H. Commun. Soil Sci. Plant Anal. 2009, 40, 3387–3398. 42. Bhatia, A.; Sasmal, S.; Jain, N.; Pathak, H.; Kumar, R.; Singh, A. Agric., Ecosyst. Environ. 2010, 136, 247–253. 43. Ma, B. L.; Wu, T. Y.; Tremblay, N.; Deen, W.; Morrison, M. J.; Mclaughlin, N. B.; Gregorich, E. G.; Stewart, G. Global Change Biol. 2010, 16, 156–170. 44. Hoben, J. P.; Gehl, R. J.; Millar, N.; Grace, P. R.; Robertson, G. P. Global Change Biol. 2011, 17, 1140–1152. 45. Velthof, G. L.; Hoving, I. E.; Dolfing, J.; Smit, A.; Kuikman, P. J.; Oenema, O. Nutr. Cycling Agroecosyst. 2010, 86, 401–412. 46. Jones, S. K.; Rees, R. M.; Skiba, U. M.; Ball, B. C. Agric., Ecosyst. Environ. 2007, 121, 74–83. 47. Choudrie, S. L.; Jackson, J.; Watterson, J. D.; Murrells, T.; Passant, N.; Thomson, A.; Cardenas, L. M.; Leech, A.; Mobbs, D. C.; Thistlewaite, G. UK Greenhouse Gas Inventory, 1990 to 2006; Annual Report for submission under the Framework Convention on Climate Change. DEFRA. United Nations Framework Convention on Climate Change, 2008. 48. Smith, P.; Goulding, K. W. T.; Smith, K. A.; Powlson, D. S.; Smith, J. U.; Falloon, P.; Coleman, K. Soil Use Manage. 2000, 16, 251–259. 49. Moran, D.; MacLeod, M.; Wall, E.; Eory, V.; McVittie, A.; Barnes, A.; Rees, R.; Topp, C. F. E.; Moxey, A. J. Agric. Econ. 2010, doi: 10.1111/j.14779552.2010.00268.x 50. Rochette, P.; Janzen, H. Nutr. Cycling Agroecosyst. 2005, 73, 171–179. 51. Drinkwater, L. E.; Wagoner, P.; Sarrantonio, M. Legume-based cropping systems have reduced carbon and nitrogen losses. Nature 1998, 396, 262–265. 52. Dobbie, K. E.; Smith, K. A. Global Change Biol. 2003, 9, 204–218. 53. Skiba, U. M.; van Dijk, S.; Ball, B. C. Soil Use Manage. 2002, 18, 340–345. 272 In Understanding Greenhouse Gas Emissions from Agricultural Management; Guo, Lei, et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 2011.


54. Godfray, H. C. J.; Beddington, J. R.; Crute, I. R.; Haddad, L.; Lawrence, D.; Muir, J. F.; Pretty, J.; Robinson, S.; Thomas, S. M.; Toulmin, C. Science 2010, 372, 812–818. 55. MacLeod, M.; Moran, D.; Eory, V.; Rees, R. M.; Barnes, A.; Topp, C. F. E.; Ball, B.; Hoad, S.; Wall, E.; McVittie, A.; Pajot, G.; Matthews, R.; Smith, P.; Moxey, A. Agric. Syst. 2010, 103, 198–209. 56. Li, C. S.; Zhuang, Y. H.; Cao, M. Q.; Crill, P.; Dai, Z. H.; Frolking, S.; Moore, B.; Salas, W.; Song, W. Z.; Wang, X. K. Nutr. Cycling Agroecosyst. 2001, 60, 159–175. 57. Zhang, F.; Qi, J.; Li, F. M.; Li, C. S.; Li, C. B. Biogeosciences 2010, 60, 2039–2050. 58. Bhatia, A.; Pathak, H.; Aggarwal, P. K. Curr. Sci. 2004, 87, 317−324. 59. Roelcke, M.; Rees, R. M.; Shengxiu, L.; Richter, J. In Soil Erosion and Dryland Farming; Laflen, J. M., Ed.; CRC Press: Boca Raton, FL, 2000; pp 103−119. 60. Castaldi, S.; Ermice, A.; Strumia, S. J. Biogeogr. 2006, 33, 401–415. 61. Mapanda, F.; Mupini, J.; Wuta, M.; Nyamangara, J.; Rees, R. M. Eur. J. Soil Sci. 2010, 61, 721–733. 62. Stehfest, E.; Bouwman, L. Nutr. Cycling Agroecosyst. 2006, 74, 207–228. 63. Smaling, E. M. A.; Braun, A. R. Commun. Soil Sci. Plant Anal. 1996, 27, 365–386. 64. Smaling, E. M. A.; Toulmin, C. Outlook Agric. 2000, 29, 193–200. 65. Snyder, C. S.; Bruulsema, T. W.; Jensen, T. L.; Fixen, P. E. Agric., Ecosyst. Environ. 2009, 133, 247–266. 66. Gregorich, E. G.; Rochette, P.; VandenBygaart, A. J.; Angers, D. A. Soil Tillage Res. 2005, 83, 53–72. 67. Steinbach, H. S.; Alvarez, R. J. Environ.Qual. 2006, 35, 3–13. 68. van Beek, C. L.; Meerburg, B. G.; Schils, R. L. M.; Verhagen, J.; Kuikman, P. J. Environ. Sci. Policy 2010, 13, 89–96. 69. Crutzen, P. J.; Mosier, A. R.; Smith, K. A.; Winiwarter, W. Atmos. Chem. Phys. 2008, 8, 389–395. 70. Barton, L.; Kiese, R.; Gatter, D.; Butterbach-Bahl, K.; Buck, R.; Hinz, C.; Murphy, D. V. Global Change Biol. 2008, 14, 177–192. 71. Di, H. J.; Cameron, K. C. Soil Use Manage. 2003, 19, 284–290. 72. Di, H. J.; Cameron, K. C.; Sherlock, R. R.; Shen, J. P.; He, J. Z.; Winefield, C. S. J. Soils Sediments 2010, 10, 943–954.


Global Nitrous Oxide Emissions: Sources and Opportunities for

Recommend Documents