Agri-environmental indicator - mineral fertiliser consumption
- Data from March 2012. Most recent data: Further Eurostat information, Main tables and Database. Planned update: June 2017.
This article provides a fact sheet of the European Union (EU) agri-environmental indicator mineral fertiliser consumption. It consists of an overview of recent data, complemented by all information on definitions, measurement methods and context needed to interpret them correctly. The mineral fertiliser consumption article is part of a set of similar fact sheets providing a complete picture of the state of the agri-environmental indicators in the EU.
Mineral fertiliser consumption is indicated by the evolution of the consumption of the nutrients nitrogen (N) and phosphor (P) with mineral fertilisers by agriculture over time, and they are measured by the following indicators:
- Application rates (kg/ha) of N and P
- Absolute volumes (tonnes) of N and P
- Application rates of organic fertilisers (kg/ha) of N and P
- 1 Main statistical findings
- 2 Data sources and availability
- 3 Context
- 4 See also
- 5 Further Eurostat information
- 6 External links
- 7 Notes
Main statistical findings
- According to Fertilizers Europe total mineral fertiliser consumption in EU-27 mounted to 10.6 million tonnes of nitrogen (N), 1.3 million tonnes phosphorous (P) and 2.9 million tonnes of potassium (K) in 2006/2007. This was respectively 11.2, 1.4 and 3.1 in 2007/2008; 9.7, 0.8 and 1.7 in 2008/2009 and 10.2, 1.0 and 2.0 in 2009/2010, 10.8 , 1.1 and 2.4 in 2010/2011 and 10.4, 1.0 and 2.2 in 2011/2012 (Figure 1).
- Data collected from the countries shows that between 2000 and 2012 total nitrogen fertiliser consumption decreased significantly in EU-15 countries, Slovenia, Norway and Switzerland but increased in Bulgaria, Czech Republic, Estonia, Latvia, Poland, Hungary and Slovakia (Table 1). The same decreasing trend can be noticed for phosphorus fertiliser consumption in EU-15 countries, Slovenia, Norway and Switzerland and an increasing trend is noticed in Slovakia, Romania, Poland and Bulgaria. From Table 2 it can be seen that phosphorus consumption is more volatile in some countries, a clear trend cannot be distinguished in the Czech Republic, Estonia, Latvia and Hungary.
- The highest mineral N fertiliser application rates in 2005 are found in regions in the Netherlands, the Poitou-Charentes region (France), the Po valley (Italy) and East Midlands (UK) (Map 1). N manure application rates are high in the Netherlands and the Po valley (Italy) as well. Manure N application is also high in Denmark, Bretagne, Northern Ireland and South-west England (Map 2). Total N fertiliser applications in 2005 are relatively high in the Netherlands, the Northwest of Germany, Denmark, the Po valley, the west coast of France, Ireland and England (Map 3).
- P mineral fertiliser applications rates in 2005 are relatively high in the north of the Paris Basin (France), and the Po valley (Italy) (Map 4). P manure applications are relatively high in the Netherlands, the Po valley (Italy), Bretagne (France), North and Eastern coast of Spain (Map 5). Total P fertiliser applications are high in NL, Northwest of Germany, Denmark, the Po valley (Italy), west coast of France, Southern Ireland, England, North and Eastern coast of Spain (Map 6).
- There is a need to establish harmonised European statistics on mineral fertiliser consumption in agriculture. In the Standing Committee for Agricultural Statistics EU Member States have agreed to submit annual data by gentlemen's agreement on mineral fertiliser N and P consumption at NUTS 0 and NUTS 2 starting in 2013. Discussions are ongoing on the possibility of setting up a survey on fertiliser and manure use and management by legal act.
National fertiliser consumption
Following the introduction of the Nitrates Directive (ND) in 1991 and the introduction of the National Action programmes for designated Nitrate Vulnerable Zones (NVZs), nitrogen fertiliser consumption has been reduced significantly in the EU-15. Data of Fertilizers Europe show that nitrogen mineral fertiliser consumption decreased between 1990 and 2010 with 19% (Table 3). Figure 2 shows the trend for EU-15 and France, Germany, the United Kingdom and Italy (which contributed to 68% of the total nitrogen fertiliser consumption in EU-15 in 2010).
Data from received from the countries show that following the introduction of the Water Framework Directive (WFD) in 2000 phosphorus fertiliser consumption decreased in all EU-15 countries between 2000 and 2010 (Table 1). Data from Fertilizers Europe show that phosphorus mineral fertiliser consumption decreased with 40% in EU-15 between 2000 and 2010 (Table 4). Figure 3 shows the trend for EU-15 and France, Spain, Germany, Italy and the United Kingdom (which contributed to 62% of the total phosphorus fertiliser consumption in EU-15 in 2010).
Though in EU-15 the mineral fertiliser consumption is decreasing, in some of the East European Member States the mineral fertiliser consumption increased between 2000 and 2010 (Table 1 and Table 2). It should be noted that mineral fertiliser consumption dropped significantly in these countries following the transition to market economies at the beginning of the 90's due to the collapse of agriculture. Table 5 shows that the average consumption per ha UAA (excluding rough grazing, permanent grassland no longer in production and common land units) is still much lower in these countries than in EU-15.
Fertilizers Europe expects the revised CAP after 2013, and the anticipated impact of the 2008 climate and energy package to be the main internal drivers in the EU for fertiliser consumption in the coming 10 years. However, recent tensions in the energy and food sectors, and their related impact on food and fertiliser prices, have been key factors in inducing the significant drop in fertiliser consumption between 2008 and 2010. This is now recovering but still has an important impact on EU agriculture. By 2021/22, Fertilizers Europe expects fertiliser consumption figures to reach 10.8 million tonnes of N, 1.1 million tonnes of P and 2.7 million tonnes of K applied to 134 million hectares. This means a relative increase in consumption of 3.4 % for N, 9.1 % for P and 18.1 % for K in EU-27 over the next 10 years.
Fertiliser application rates
There is a broad recognition in many countries that above-optimal applications of fertiliser nutrients such as N and P lead to an enhanced risk of pollution to watercourses, and associated problems with water quality. The Member States have different application rates of N and P fertiliser for different crops. In particular, wheat, barley, grain maize, potato, sugar beet, oilseed rape, vegetables and industrial crops have high application rates of N fertiliser. To identify areas at risk of nutrient surplus the actual area fertilised should be taken into account. Data on application rates and fertilised areas have been requested from the countries by Eurostat, however only a few countries submitted data, they are therefore not presented here. Map 1 to Map 6 show estimated application rates of N and P from mineral fertilisers by the Joint Research Centre of manure, mineral fertilisers and manure and mineral fertilisers combined.
Data sources and availability
Mineral fertiliser consumption is indicated by the evolution of the consumption of the nutrients nitrogen (N) and phosphor (P) with mineral fertilisers by agriculture over time.
- Application rates (kg/ha) of N and P
- Absolute volumes (tonnes) of N and P
- Application rates of organic fertilisers (kg/ha) of N and P
Links with other indicators
The consumption of nitrogen and phosphorus fertilisers are linked to the following indicators:
- AEI 08 - Energy use (indirect)
- AEI 12 - Intensification/Extensification
- AEI 15 - Gross nitrogen balance
- AEI 16 - Risk of pollution by phosphorous
- AEI 18 - Ammonia emissions
- AEI 19 - Greenhouse gas emissions
- AEI 26 - Soil quality
- AEI 27.1 - Water quality (Nitrate pollution)
and depend on:
- AEI 04 - Area under organic farming (see Organic farming statistics)
- AEI 10.1 - Cropping pattern
- AEI 10.2 - Livestock pattern
Data used and methodology
Data on fertiliser consumption at NUTS 0 level is not only needed for this indicator but also for other AEI such as AEI 15 - Gross nitrogen balance, AEI 16 - Risk of pollution by phosphorus, AEI 18 - Ammonia emissions and AEI 19 - GHG emissions. AEI 15 and AEI 16 require data at regional level (NUTS 2) as well. For the estimation of NH3 emissions the distribution of national fertiliser use by type of fertiliser is needed (ammonium sulphate, ammonium nitrate, calcium ammonium nitrate, anhydrous ammonia, ammonium phosphate, urea, urea-ammonium nitrate solution (UAN), and other N fertilisers). There is no policy requirement for fertiliser data at crop level: The EMEP Guidebook (NH3 and NO emissions) and the IPCCC Guidelines (GHG emissions) do not directly require fertiliser data to be available by crop. However, the EMEP Guidebook notes that where spatially disaggregated inventories of fertilised culture emissions are required the emissions due to N-fertiliser application may be spatially disaggregated using census data on the distribution of different crops and application data statistics, together with mean fertiliser-N inputs to those crops, and climatic information. The IPCCC Guidelines note that if sufficient data are available, fertiliser use may be disaggregated by fertiliser type, crop type and climatic regime for major crops. These data may be useful in developing revised emission estimates if inventory methods are improved in the future. The AEI 18 (GHG emissions) and AEI 19 (NH3 emissions) are specified at national level.
Although data on fertiliser consumption is of high importance for many policies and indicators, official statistics do not exist at EU-level. DireDate (research project on identifying data needs to establish the 28 AEI) recommended to set up a combination of national production/trade data, expert judgment and small sample farm surveys. Data from production/sales statistics may overestimate the use of mineral fertilisers due to the inclusion of intermediary goods and non-agricultural use, and, as described above, confidentiality issues may cause data on sales and production to be difficult to receive. On the other hand, the accuracy of farmer surveys depends on the sampling design, sample size and length of the survey and they may be costly and place a high burden on respondents. Despite that, several MS however already carry out farmer surveys for several years. Eurostat is currently negotiating the possibility of collecting data on fertilisers from a farm level survey.
The data sources used in the assessment of this indicator are:
- Data from Fertilizers Europe. This is an harmonized data source. Data are available at NUTS0 for EU-27 and Norway. Data from Fertilizers Europe relate to crop years (t-1/t) which are reported under year t-1. Data were originally received in kilo tonnes of nitrogen (N), phosphate (P2O5) and potash (K2O). Phosphate and potash and were transformed into phosphorus (P) and potassium (K) by multiplying the data with 62/142 and 78/94 respectively. Data have been rounded to 1000s of tonnes of nitrogen, phosphorus and potassium.
- Data from countries. Provisional data on tonnes of N and P inorganic fertiliser consumption for year t are transmitted by 1 May year t + 1, final data are submitted by 1 December annually at NUTS 0 and NUTS 2. This data source is however not harmonised, data have been derived from different types of data sources in Member States, such as farm surveys, production/trade statistics, sales statistics, administrative records etc). Official statistics on mineral fertiliser use are lacking in some countries, Data were not complete for Greece, Malta, Lithuania, Cyprus and Italy at NUTS 0. At regional level data are only available for a few countries and for a limited period of time. The reference period is the calendar year; data collected for crop years (t-1/t) can be reported in calendar year t, no corrections are made. Data at NUTS 0 level have been rounded to 500s of tonnes of nitrogen, and phosphorus. No rounding has been applied to data at NUTS 2 level.
Other existing data sources on fertilisers include:
- Data on trade and production of fertilisers by type in COMEXT and PRODCOM. Due to confidentiality issues some data is missing and/or partially available. Methodological problems also complicate the estimation of apparent consumption from data in PRODCOM and COMEXT (Due to confidentiality issues, data are often reported in a very general classification which makes linkage of PRODCOM with COMEXT or translation of volumes into nutrient contents difficult. Fertilisers which are sold to another fertiliser company may be further processed which leads to double counting. Fertilisers sold may also be used for other intentions than agricultural production). Expert knowledge could improve the estimation of apparent consumption from trade and production data, however is prehibitated due to confidentiality issues.
- Data on production and trade by type from the FAO, for which similar complications exist as mentioned above.
- Data on the use of mineral fertilisers were also collected from MS by a one-time survey in 2010, the Joint Eurostat/OECD Questionnaire on agri-environmental indicators and gross nutrient balances (AEI Questionnaire). This data source is however not harmonised, data have been derived from different types of data sources in Member States, such as farm surveys, production/trade statistics, sales statistics, administrative records etc). Official statistics on mineral fertiliser use are lacking in some countries. Countries have used different data sources and data may refer to different time-periods (see discussion under methodology). Data of this source are therefore not directly comparable between countries.
Limitations of data
The use of mineral fertilisers can not be seen separate from the use of manure and other organic fertilisers, the cultivation of leguminous crops. This indicator could be improved if the use of manure and other organic fertilisers would be considered as well. Data on inorganic fertilisers, manure and other organic fertilisers are also needed for AEI 15 (Gross nitrogen balances), AEI 16 (Risk of pollution by phosphorous), AEI 18 (Ammonia emissions) and AEI 19 (Greenhouse gas emissions). For the calculation of emissions not only the amount of fertilisers and manure used is important but also the application technique, incorporation, storage, animal housing etc. As it are also these interactions which are of interest for most policies (Nitrates Directive, Water Framework Directive, Rural Development Programme, United Nations Framework Convention on Climate Change, United Nations Economic Commission for Europe Convention on Long-range Transboundary Air Pollution) the collection of these data in a single survey would be preferable. Collecting data in a geo-referenced sample survey would allow the use of these data for modelling environmental impacts at finer spatial scales. To identify areas at risk, not only data on applications are needed but also data on fertilised areas.
Data from Fertilizers Europe cannot be compared with data received from countries, due to differences in reference periods, data sources and methodology see data sources.
For the comparison of consumption per ha UAA, the area of UAA have been corrected to exclude common land, permanent grassland no longer under production and rough grazings. It is assumed that these areas are not significantly fertilised. Common lands have however been included in different ways by countries. A minor part of the common land in Germany, Spain and Italy and the total area of common land in Cyprus and Norway are therefore still included. Data are therefore not directly comparable across countries. The estimated consumption of fertilisers per ha has been estimated from data on fertiliser consumption rounded to 500s of tonnes and hectares rounded to 1000s of hectares.
Nutrients, such as nitrogen (N) and phosphorus (P), are absorbed from the soil by plants for their growth. Mineral or inorganic fertilisers are widely used in agriculture to optimise production, and organic fertilisers are a significant additional source of nutrient input. Organic farmers do not apply synthetic mineral fertilisers. Nitrogen and phosphorus fertilisers greatly enhance crop production, but losses of nitrogen and phosphorus from agriculture contribute to loss of biodiversity, climate change, acidification and pollution. N and P behave differently in terms of their availability for loss from the agricultural system. N is highly soluble with limited build-up in the soils, and research shows a positive relationship between application rate and nitrate lost from the soil root zone. P losses from land occur due to soil erosion and agricultural run-off. Historic over-fertilisation of P can build up soil P reserves to high levels and under such conditions it is possible for significant pollution to take place even with negligible new fertiliser inputs. However, the main focus of losses is related to the timing and loading of inputs of N and P either from fertiliser or organic manure applications.
Food production has become highly depending on mineral P fertilisers. The main source of P in the world is phosphate rock, which is a non-renewable resource. The majority of phosphate rock reserves in the world are concentrated in a few countries, none of them EU Member States. Studies show that cheap and high quality rock reserves may become depleted in the near future, which with increasing demand due to an increasing world population and changing diets, may result in increasing prices of P fertilisers which would also impact food prices. Some 80 % of phosphorus use is in agriculture, mainly as fertilisers. There are also industrial uses, but these are more marginal and the most important of them, use in detergents, is being phased out at least in the EU. Currently there are many losses from mining to food production, it is estimated that only one-fifth of the P mined for P mineral fertiliser production is in the end consumed by the human population. Many of these losses contribute to environmental problems due to phosphorus pollution. Sustainable use of P includes recovering P from loss pathways such as sewage and waste, but also appropriate fertilisation practices.
Organic fertilisers may consist of manure, composts and sewage sludge. These organic fertilisers are important sources of N and P, especially on livestock farms and farms near urban areas, and should be used as priority over mineral fertilisers. Increasing the effectiveness of their use will contribute to decreased use of mineral fertiliser use and also to reduced losses of nitrogen and phosphorus.
Policy relevance and context
Application of fertilisers is a major contributory factor to increased losses of nutrients such as nitrate and phosphate from agricultural soils into ground and surface water bodies. This loss can occur via run-off along the soil surface or as subsurface loss via leaching and drainflow. As a consequence, legislative initiatives through the Nitrates Directive (Directive 0676/1991) and more recently the Water Framework Directive (Directive 0060/2000) have sought to limit nutrient losses to water bodies through more careful management of agricultural land. In the case of the Nitrates Directive, this has included the designation of nitrate vulnerable zones (NVZs), establishment of Code(s) of Good Agricultural Practice to be implemented by farmers on a voluntary basis, establishment of Action Programmes to be implemented by farmers within NVZs on a compulsory basis, and national monitoring and reporting every 4 years.
The Codes of Good Agricultural Practice include measures limiting the time when fertilisers can be applied on land, in order to allow N availability only when the crop needs nutrients and measures limiting the conditions for fertiliser application (steeply sloping ground, frozen or snow covered ground, near water courses). The Action Programmes are based on Action Standards contained in the Code of Good Agricultural Practice which become binding for farmers in NVZs and other measures such as limitation of fertilisers to be applied taking into account crops needs, all N inputs and soil supply, maximum amount of animal manure to be applied (corresponding to 170 kg N organic/hectare/year). In the legislative text of the Water Framework Directive, an indicative list of pollutants includes organophosphorous compounds and substances that contribute to eutrophication (in particular nitrates and phosphates). Measures suggested in this context are aimed at reducing the influx of nutrients, such as nitrogen and phosphorus to the groundwater and surface waters and include the reduction of nutrient application, the modification of cultivation techniques, the proper handling of fertilisers, and the prevention of soil erosion through erosion minimising soil cultivation.
Other agri-environmental policies that affect the consumption of nitrogen and phosphorus fertilisers, directly or indirectly include:
- United Nations Framework Convention on Climate Change (UNFCCC): The Kyoto Protocol is an international agreement linked to the UNFCCC. The major feature of the Kyoto Protocol is that it sets binding targets for 37 industrialized countries and the European community for reducing greenhouse gas (GHG) emissions. These amount to an average of five per cent against 1990 levels over the five-year period 2008-2012. The major distinction between the Protocol and the Convention is that while the Convention encouraged industrialised countries to stabilize GHG emissions (CO2, CH4, N2O, PFCs, HFCs, SO2, NOx, CO and NMVOC), the Protocol commits them to do so. Reporting is done by the countries by submitting annual emission inventories and national reports. The application of mineral nitrogen fertilisers by agriculture is one of the items to be reported.
- National Emissions Ceiling Directive (NECD): Directive 0081/2001 sets upper limits for each Member State for the total emissions in 2010 of the four pollutants responsible for acidification, eutrophication and ground-level ozone pollution (sulphur dioxide, nitrogen oxides, volatile organic compounds and ammonia), but leaves it largely to the Member States to decide which measures – on top of Community legislation for specific source categories - to take in order to comply. The implementation of the directive has required Member States to develop national programmes in 2002 and, where needed, to revise those plans in 2006. They aim at meeting fixed ceilings of national emissions by 2010 and thereafter. Furthermore, Member States have to report their emission inventories to the EEA and the European Commission in order to monitor progress and verify compliance.
- UNECE Convention on Long-range Transboundary Air Pollution: Parallel to the development of the EU NEC Directive, the EU Member States together with other European countries, the United States and Canada have negotiated the "multi-pollutant" protocol under the (the so-called Gothenburg protocol, agreed in November 1999). The emission ceilings in the protocol are equal or less ambitious than those in the NEC Directive.
- Common Agricultural Policy (CAP). In 2003 cross compliance was introduced in the CAP. This mechanism ties EU support (direct payments and certain rural development and wine sector payments) for farmers to compliance with standards of environmental care and public/animal/plant health and animal welfare. Next to statutory management requirements that apply to all farmers (even those not receiving the type of EU support covered by cross compliance), the farmers receiving CAP payments have to apply a set of rules on good agricultural and environmental condition (GAEC). These GAEC are designed to prevent soil erosion, maintain soil organic matter and soil structure, ensure a minimum level of maintenance, avoid the deterioration of habitats and protect and manage water. Cross compliance penalizes farmers who infringe EU law on environmental, public and animal health, animal welfare or land management – by reducing the EU support they receive.
- Rural development programme: The agri-environmental measures were introduced in 1992 under the MacSharry reform of the CAP, integrated as an obligatory measure within the Rural Development Regulation in 1999 in order to promote environmental friendly farm practices. The key objectives of these measures are to promote agricultural methods to protect the environment, maintain the countryside or improve animal welfare. The Member States develop their own agri-environment measures according to their environmental needs. Farmers receive financial compensations covering the income foregone, costs incurred and as an incentive for their participation in agri-environmental schemes that go beyond the relevant mandatory standards established pursuant to Articles 4 and 5 of and Annexes III and IV to Regulation 1782/2003 as well as other minimum requirements for fertiliser and plant protection product use. Various agri-environment measures throughout the European Union have been established directly or indirectly addressing diffuse contamination by phosphorus and nitrogen. Some of these measures are directed at mitigating soil erosion such as crop rotations, mulch seeding retaining stubble after harvest and ploughing restrictions. Other measures tackle the problem of excess nutrients through reduced fertiliser use. All measures that impact soil erosion and nutrient balances ultimately result in a reduction of diffuse contamination by phosphates and nitrates from agricultural land.
- The Birds Directive and the Habitats Directive: The main purpose of the Habitats Directive is to ensure biological diversity through the conservation of natural habitats and of wild flora and fauna within the European territory, while taking into account economic, social, cultural and regional requirements. Farmers who have agricultural land in Natura 2000 sites and face restrictions due to the requirements of the Habitat-Directive are eligible to receive payments for the management of these sites by the Rural Development Regulation, which helps promote environmental-friendly farming. Depending on the specific conditions of a certain area, these include measures to reduce the use of pesticides and fertilisers, measures to mitigate the effects of soil compaction, e.g. limitations on the use of machinery or the setting of stocking limits, or measures aiming to regulate the irrigation of agricultural land.
To assess the effectiveness of these policies detailed information on the consumption of nitrogen and phosphorus fertilisers are required.
The intensity of fertiliser use has implications for agricultural production and the potential environmental impacts of nutrient run-off from farmland. Agricultural research shows that nutrient requirements (and hence consumption) vary for different crop types and yield expectations and are influenced by previous land management, soil type and climatic factors.
This indicator is much linked to the indicators AEI 15 - Gross nitrogen balance, AEI 16 - Risk of phosphorus pollution, AEI 18 - Ammonia emissions, AEI 19 - GHG emissions and AEI 27.1 - Water quality - nitrate pollution, and more information can be found on the agri-environmental context in the fact sheets of these indicators.
This indicator represents partial nutrient inputs to the agricultural system (the other main inputs being applications of manures and slurries, other organic fertilisers, biological N fixation and atmospheric N deposition). The total inputs and outputs of N and P of agricultural land are considered in AEI 15 and AEI 16. Excessive use of N fertiliser can lead to an increase of nitrate levels in water (see AEI 27.1) and hereby cause eutrophication, which can lead to toxic algal blooms and fish kills. Excessive use of P mineral fertilisers can lead to water pollution by P, contributing to eutrophication. With the application of N fertilisers to the land N-emissions can occur, contributing to acidification (see AEI 18) and climate change (see AEI 19). N mineral fertilisers are produced using high amounts of energy (gas), and therefore contributes to GHG emissions and fossil fuel depletion. Some environmental pollution due to the production of P mineral fertilisers are related to the contamination of phosphate rock with heavy metals and other elements, once released to the environment or transferred to soils these may pose a risk to ecosystemns and humans.
- Agri-environmental indicators (online publication)
Further Eurostat information
- Agriculture, forestry and fishery statistics — 2016 edition
- Agriculture, forestry and fishery statistics - 2012 edition
- Environmental statistics and accounts in Europe - 2010 edition
- Food: from farm to fork statistics - 2011 edition
Methodology / Metadata
- Consumption estimate of manufactured fertilizers (source: Fertilizers Europe) (aei_fm_manfert_esms)
- Use of inorganic fertilizers (aei_fm_usefert_esms)
Source data for tables, figures and maps (MS Excel)
- Commission Communication - Development of agri-environmental indicators for monitoring the integration of environmental concerns into the common agricultural policy
- Commission Staff working document accompanying COM(2006)508 final
- Corresponding IRENA Fact sheet: IRENA 08
- Forecast of food, farming and fertiliser use in the European Union 2012 - 2022, Fertilizers Europe.
- Dana Cordell, Jan-Olof Drangert, Stuart White, The story of phosphorus: Global food security and food for thought, Global Environmental Change, Volume 19, Issue 2, May 2009, Pages 292-305, ISSN 0959-3780
- Schroder, J.J., Cordell, D.J., Smit, A.L., Rosemarin, A. 2010, 'Sustainable use of phosphorus', Plant Research International, Wageningen University and Research Centre, Wageningen, pp. 1-140. pdf
- IFA, 2007. Fertilizer Best Management Practices. General Principles, Strategy for their Adoption and Voluntary Initiatives vs Regulations. International Fertilizer Industry Association, Paris, France, 259 pp
- Mosier, A.R., Syers, J.K., Freney, J.R., (Eds.), 2004. Agriculture and the Nitrogen Cycle. Assessing the Impacts of Fertilizer Use on Food Production and the Environment. SCOPE 65. Island Press, Washington, USA, 296 pp.