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Chapter 11: Agri-environment

Updated 20 February 2024

Summary

• Estimated greenhouse gas and air pollution emissions from agriculture have fallen between the year 2000 and 2021.
• Since the late 1990’s nitrogen and phosphate fertiliser application rates have fallen.
• A comparison of soil nutrient balances (in kg per hectare) from the year 2020 to 2021 shows a 5.3% increase for nitrogen and a 17% decrease for phosphorus.
• The farmland bird index, a good indicator for general biodiversity on farms, has decreased since 1970 with the index for all farmland species in 2021 less than half of 1970 levels.

Introduction

Whilst agriculture contributes less than 1% to the United Kingdom’s economy, it provides around three-quarters of the indigenous food we eat and is responsible for around 70% of land use. As well as being vital for food production, agriculture helps to shape the landscape, providing important recreational, spiritual and other cultural benefits. This can be viewed in terms of delivering vital ecosystems services, with food production being a provisioning service whilst other environmental and societal benefits are delivered by, for example, cultural and regulating services.

Agricultural production and the associated land use and management are key drivers of the environmental impacts from the sector. A key challenge is to decouple production from its environmental impact so that production can be increased whilst reducing the overall environmental footprint.

Farm practices and the use of inputs (particularly fertilisers and pesticides) directly influence the environmental pressures from farming including the quality, composition and availability of habitats and impact on air, water and soils.

In recent years, the key drivers of change in terms of environmental pressures from agriculture are declines in the number of livestock, specifically ruminants, and reductions in fertiliser applications, particularly on grassland. Reforms to the Common Agricultural Policy, and in particular the decoupling of subsidy payments from production, have been instrumental to these drivers of change. As a result of these reforms, agriculture has become more responsive to market conditions which may influence both positive and negative environmental impacts.

All the data presented in this chapter is the most recent at the time of publication. Links to further information on source data has been provided for each section of this chapter.

Emissions

Figure 11.1 Emissions from agriculture (%)

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Emission	Other sectors, use or sources	Agriculture	Total
Methane	51%	49%	100%
Nitrous oxide	29%	71%	100%
Carbon dioxide	98%	2%	100%
Total GHG emissions	89%	11%	100%
Ammonia	13%	87%	100%

Notes:

1. The entire time series is revised each year to take account of methodological improvements in the UK emissions inventory.

Source: UK greenhouse gas emissions, Department for Business, Energy and Industrial Strategy, Emissions of Air Pollutants, Defra

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Agriculture accounts for approximately 11% of total greenhouse gas emissions in the UK. Three greenhouse gasses emitted by agriculture are nitrous oxide, methane and carbon dioxide.

Agriculture is a major source of both nitrous oxide and methane emissions in the UK, accounting for 71% of total nitrous oxide emissions and 49% of all methane emissions in 2021. In contrast, agriculture only accounted for about 2% of total carbon dioxide emissions in the UK.

Figure 11.2 Nitrous oxide emissions (million tonnes carbon dioxide equivalent)

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year	Non-agriculture	Agriculture	UK total
2010	6.7	13.9	20.6
2011	5.9	13.9	19.9
2012	5.8	13.8	19.6
2013	5.8	13.8	19.6
2014	5.7	14.4	20.1
2015	5.7	14.2	19.9
2016	5.6	13.8	19.5
2017	5.7	14.2	19.8
2018	5.7	14.0	19.7
2019	5.7	14.1	19.8
2020	5.4	13.2	18.6
2021	5.5	13.6	19.1

Notes:

1. The entire time series is revised each year to take account of methodological improvements in the UK emissions inventory.

Source: UK greenhouse gas emissions, Department for Business, Energy and Industrial Strategy

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The majority of agricultural nitrous oxide emissions are sourced from soils, particularly as a result of nitrogen fertiliser application, manure (both applied and excreted on pasture) and leaching/run-off. In 2021 nitrous oxide emissions from agriculture are estimated to have fallen by approximately 18% since 1990 and approximately 14% since 2000 (see Figure 11.2). This is consistent with trends in fertiliser usage over the same period.

Figure 11.3 Methane emissions (million tonnes carbon dioxide equivalent)

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year	Non-agriculture	Agriculture	UK total
2010	47.1	28.2	75.2
2011	44.3	28.0	72.3
2012	42.6	27.9	70.5
2013	38.1	27.7	65.8
2014	35.1	28.5	63.6
2015	33.9	28.6	62.5
2016	32.0	28.5	60.5
2017	32.3	28.6	60.9
2018	32.4	28.1	60.4
2019	31.9	28.1	60.0
2020	29.8	27.7	57.5
2021	29.1	27.9	57.0

Notes:

1. The entire time series is revised each year to take account of methodological improvements in the UK emissions inventory.

Source: UK greenhouse gas emissions, Department for Business, Energy and Industrial Strategy

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The majority of methane emissions from agriculture arise from enteric fermentation (digestive processes) in ruminating animals, with manure management practices accounting for the remainder. In 2021, methane emissions from agriculture are estimated to have fallen by 14% since 1990 and 12% since 2000 (see Figure 11.3), mainly as a result of decreasing livestock numbers, particularly in cattle.

Further information on greenhouse gas emissions from agriculture

Ammonia emissions impact on air quality and subsequently human and animal health. High nutrient concentrations, particularly phosphorus, can cause nutrient enrichment (eutrophication) resulting in excessive growth of macrophytes and algae which can deplete dissolved oxygen levels. Deposition of ammonia can damage sensitive habitats due to eutrophication and the acidification of soils.

Figure 11.4 Ammonia Emissions (thousand tonnes)

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year	Non-agriculture	Agriculture	UK total
2010	37.5	223.9	261.4
2011	37.4	223.6	261.0
2012	36.4	223.7	260.1
2013	35.0	220.5	255.5
2014	33.7	233.2	266.8
2015	32.3	236.8	269.0
2016	32.5	238.5	271.0
2017	33.2	240.8	274.0
2018	32.2	237.8	270.1
2019	32.2	237.0	269.2
2020	33.4	226.7	260.1
2021	34.5	230.5	265.0

Source: Emissions of Air Pollutants, Defra

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In 2021 agriculture accounted for 87% of the UK’s ammonia emissions. The main sources of ammonia emissions in the UK are agricultural soils and livestock, in particular cattle. In 2021 ammonia emissions from agriculture are estimated to have fallen by 17% since 1990 and 7.3% since 2000 (see Figure 11.4) due to long-term reductions in cattle numbers and more efficient fertiliser use. Despite decreasing over time, ammonia emissions have slightly increased over the past few years since emissions from agriculture reached their lowest point in 2013. This recent increase is largely due to an increase in ammonia emissions from agricultural soils.

Further information on emissions of air pollutants.

Pesticide usage

Plant protection products (pesticides) are used to regulate growth and to manage pests and diseases in crops. They play a major role in maintaining high crop yields and therefore greater production from agricultural land. However, they can have detrimental impacts on the environment, particularly on terrestrial and aquatic biodiversity.

The need for pesticide usage varies from year to year depending on growing conditions, particularly the weather which influences disease, weed and pest pressures. In addition, longer term variations are due to changes in the range and activity of active substances, the economics of pest control, and resistance issues. In the United Kingdom the treated area of arable crops (number of hectares multiplied by number of applications) has remained relatively stable since 2008, whilst the total amount of pesticide applied (kg/ha) has shown an overall decline.

In recent years cereals accounted for the majority of both treated area and the weight of pesticides applied to arable crops in the United Kingdom. Figure 11.5 shows the application rates for different types of pesticides used on cereal crops in Great Britain. The majority of UK cereals (more than 80%) are grown in England.

Figure 11.5 Pesticide use on cereals, Great Britain (kg/ha)

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year	Fungicides	Growth regulators	Herbicides	Insecticides	Molluscicides	Total
2010	0.20	0.60	0.39	0.07	0.19	1.46
2012	0.20	0.50	0.41	0.05	0.15	1.32
2014	0.22	0.49	0.40	0.03	0.13	1.27
2016	0.24	0.48	0.45	0.02	0.11	1.30
2018	0.24	0.47	0.48	0.02	0.12	1.32
2020	0.21	0.45	0.41	0.01	0.10	1.18

Notes:

1. All pesticides include seed treatments.

Source: Pesticide usage survey

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Further information can be found on the pesticide usage webpage.

Fertiliser usage

Nitrogen and phosphorous are key nutrients needed for crop growth. A deficit in either or both of these nutrients can have a negative impact on crop yields and levels of production. The main source of these nutrients are mineral fertilisers and organic fertilisers such as manures and slurries from livestock.

Fertilisers can have an adverse impact on the environment depending on the application method, through over-application and natural losses from soils and manures. These impacts include water quality (nitrogen and phosphorous levels in waterbodies), air quality (ammonia emissions) and climate change (nitrous oxide emissions).

Most agricultural soils do not contain enough naturally occurring plant-available nitrogen to meet the needs of a crop throughout the growing season so supplementary nitrogen applications are needed each year. Nitrogen usually has a large immediate effect on crop growth, yield and quality. Correct rate and timing of applications is important to ensure crop growth requirements are met.

Figure 11.6 Nitrogen (N) use (kg/ha) on all crops and grass, Great Britain

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Notes:

1. Cropped land is tillage crops.

Source: British survey of fertiliser practice

Text description of Figure 11.6: Figure 11.6 is a line chart showing nitrogen use on all crops and grass from 1990 to 2021. Nitrogen use has shown a decline on grassland, steadily decreasing from around 1998 and levelling off in around 2008, since when rates of use have been similar. Nitrogen use on cropped land remained at similar levels but has decreased in recent years.

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In Great Britain between 1990 and 2018 the overall mineral nitrogen application rate on tillage crops was largely in the range of 140 -150 kg/ha, but it has declined in recent years. The rate of nitrogen application increased by 9 kg/ha to 130 kg/ha in 2021 compared to 2020.

For grassland, nutrient application rates have always been lower than for cropped land. Between 1990 and 2021 there has been a downward trend in the overall mineral nitrogen application rate on grassland and in 2021 the rate was 51 kg/ha, the lowest rate recorded since 1984. A reduction in total cattle numbers is thought to have contributed to this, possibly in conjunction with some improvements in manure use efficiency.

Phosphate is applied in fertilisers and manures, particularly to replace the quantities removed in harvested crops. Most British soils can hold large quantities of phosphate in forms that are available for crop uptake over several years. Therefore, managing the supply of phosphate is based on maintaining appropriate levels in the soil with the timing of applications less critical

Figure 11.7 Phosphate (P₂O5) use (kg/ha) on all crops and grass, Great Britain

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Notes:

1. Cropped land is tillage crops.

Source: British survey of fertiliser practice

Text description of Figure 11.7: Figure 11.7 is a line chart showing phosphate use on all crops and grass from 1990 to 2021. Whilst overall use has been higher on cropped land, the trends of phosphate use on cropped land and grassland have been similar, showing a steady overall decline. In the past few years, the decline in use on cropped land has continued, whereas rates of use on grassland have remained similar.

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From 1990 to 2021 total mineral phosphate application rates have more than halved to a rate of 14kg/ha in 2021. More recently the decline has levelled off with a similar rate seen since 2012. For grassland, rates applied have always been less than on cropped land. Both rates on grassland and cropped land have shown an overall downward trend between 1990 and 2021, with rates applied on grassland remaining at a similar rate for the last few years.

Annual levels of use of nitrogen and phosphate application are influenced by fertiliser prices, crop prices, crop type and weather-related issues during the growing season, for example the fall in phosphorus application rates in 2009 was related to high fertiliser prices and the changes in nitrogen use seen in 2019/20 reflect exceptional changes in the balance of the winter and spring cropping seasons (see Figures 11.6 and 11.7).

Further information on fertiliser usage.

Soil health

The success of UK agriculture depends upon healthy soils; they are arguably a farmer’s most valuable asset. Soil degradation costs England and Wales an estimated £0.9bn - £1.4bn per year ^{[footnote 1]}. In the face of a changing climate and increase in food demand, it is important to mitigate the risks to long-term productive capacity and encourage famers to manage their soils in a sustainable way. While rates of soil erosion in England are not excessively high, it is estimated to affect around 17% of land in England and Wales with impacts in the form of loss of productive capacity and nutrients, but also off-site costs to the environment. Around 3.9 million hectares of our soils are at risk of soil compaction which could lead to a total yield penalty of around £163 million per year ^{[footnote 1]}.

Actions to improve soil organic matter can be mutually beneficial for soil and production. For example, early establishment of crops in the autumn reduces soil erosion risk during the late autumn and winter months ^{[footnote 2]} and can also increase winter cereal yields ^{[footnote 3]}.

Soil nutrient balances provide an indication of the overall environmental pressure from nitrogen and phosphorus in agricultural soils. They measure the difference between nutrients applied to soils (largely as fertilisers and manures) and those removed from soils by the growth of crops, including grass for fodder and grazing.

An increase in the balance per hectare indicates a greater environmental risk from nutrient losses and their associated emissions whereas a decrease in the balance per hectare broadly indicates a reduced environmental risk. However, there is a risk that nutrient deficits lead to poor soil fertility and subsequent loss of yields.

Figure 11.8 Nitrogen (N) soil nutrient balance (kg/ha)

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Notes:

1. The series break in 2009 is due to changes in farm survey data collection.
2. From 2010 in England, June survey data for land and animals is collected only for commercial farms.
3. From 2000 to 2008 data is for all farms and hence based on a larger population.
4. For comparability, data for 2009 have been presented on both the definition used for 2000 to 2008 and that used from 2010 onwards.

Source: Soil nutrient balances

Text description of Figure 11.8: Figure 11.8 is a line chart showing the nitrogen soil nutrient balance on farms from 2000 to 2021. Balances have fluctuated slightly over time, but have remained between 80 kg/ha and 100 kg/ha since 2002.

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Provisional estimates for 2021 show that the nitrogen balance for the UK was a surplus of 95 kg/ha on managed agricultural land (see Figure 11.8).This is an increase of 5 kg/ha ( 5.3%) to the nitrogen balance surplus compared to 2020. This was driven by an increase in inputs of 7.8 kg/ha (4.2%) (mainly from increased use of inorganic manufactured fertilisers) which was partially offset by an increase in offtake of 3.0 kg/ha (3.1%) (mainly from increased cereal production) over the same period.

The longer-term trend shows a reduction of 13.4 kg/ha (12%) to the nitrogen balance surplus compared to 2000. Over this time, inputs decreased by 42 kg/ha (18%), which more than offset a decrease in offtake of 28 kg/ha (22%).The main drivers for this fall have been reductions in the application of inorganic (manufactured) fertilisers and manure production due to lower livestock numbers, The main driver behind the decrease in offtake was a reduction in forage due to a reduction in livestock numbers.

Figure 11.9 Phosphorus (P) soil nutrient balance (kg/ha)

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Notes:

1. The series break in 2009 is due to changes in farm survey data collection.
2. From 2010 in England, June survey data for land and animals is collected only for commercial farms.
3. From 2000 to 2008 data is for all farms and hence based on a larger population.
4. For comparability, data for 2009 have been presented on both the definition used for 2000 to 2008 and that used from 2010 onwards.

Source: Source: Soil nutrient balances

Text description for Figure 11.9: Figure 11.9 is a line chart showing the phosphorus soil nutrient balance on farms from 2000 to 2021. Following an overall steady decline from approximately 10 kg/ha in 2000 to approximately 4 kg/ha in 2009, the soil nutrient balance has since fluctuated but remained between 4 and 8 kg/ha to 2021.

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Provisional estimates for 2021 show that the phosphorus balance for the UK was a surplus of 5.7 kg/ha on managed agricultural land (see Figure 11.9).

This is a decrease of -1.2 kg/ha (17%) to the phosphorus balance surplus compared to 2020.The biggest contribution to the decrease was made by increased offtake from cereal production.

The longer-term trend (compared to 2000) shows an overall reduction of -3.8 kg/ha (40%).Over this time, inputs of phosphorus decreased by 8.0 kg/ha (26%), which more than offset a decrease in offtake of 4.2 kg/ha (20%). As with nitrogen, the main drivers behind the decrease in phosphorus inputs were reductions in the application of both inorganic fertilisers and cattle manure.The main driver behind the decrease in offtake was a reduction in forage due to reduced livestock numbers.

Further information found on the soil nutrient balances publication can be found here

Water abstraction

Water abstraction from groundwater and surface water sources may be needed for irrigation purposes to maintain high yields and good crop quality, particularly in areas with low rainfall and for certain crop types. Over abstraction can be detrimental to aquatic ecosystems and limit resource for other industries.

Volumes of water abstracted for agricultural purposes is highly variable from year to year and greatly influenced by rainfall amounts, especially during the growing season. In 2018, agriculture was responsible for 1% of total water abstraction in England. As demonstrated in Figure 11.10, in 2018, the recorded abstraction rate in England was 150 million cubic litres, an increase from 109 million cubic litres in 2017. This was due to an increase in spray irrigation of 48%, whereas other abstraction for other agriculutral purposes remained similar to 2017 levels.

Figure 11.10 Water abstraction, England (million cubic metres)

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year	Other agriculture	Spray irrigation	Total
2010	25	104	129
2011	26	118	144
2012	26	50	76
2013	26	100	126
2014	27	89	116
2015	25	94	119
2016	26	84	110
2017	22	87	109
2018	21	129	150

Notes:

1. Spray irrigation includes small amounts of non-agricultural irrigation.
2. 2015 figure has a break in the series where information concerning abstractions in the country of England and the Dee/Wye regional charge areas (formally the Wales regional charge area) has been amalgamated into the North West and Midlands regional charge areas respectively.

Source: Water abstraction in England

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Further information on the water abstraction webpage.

Water quality

Due to the implementation of the Water Framework Directive (WFD) a revised approach to monitoring water quality across the UK was introduced in 2009. The WFD assesses water quality using three categories (ecological quality, chemical quality and hydrological quality). For each site each category is assigned a grade which is then combined to provide an overall classification. The combined score is based on ‘one out, all out’, e.g., if one category is ranked as ‘poor’ the water body will be classified as ‘poor’.

High nutrient concentrations, particularly phosphorus, can cause nutrient enrichment (eutrophication) resulting in excessive growth of macrophytes and algae which can deplete dissolved oxygen levels. Excessive levels of nutrients must be removed from water bodies used for drinking water to meet legal limits, with water companies incurring significant costs. It has been estimated that agriculture accounts for around 61% of the total nitrogen in river water in England and Wales ^{[footnote 4]} and around 28% of the total phosphorus load in river water in Great Britain ^{[footnote 5]}, although this estimate may also include phosphorus from septic tanks ^{[footnote 6]}.

Agriculture contributes to the pollution of water bodies through the leaching of fertilisers, pesticides, and manure (nutrients and faecal bacteria) as well as an increase in sediments. Rainfall may wash a proportion of fertiliser off fields into local water bodies or cause soluble nutrients to filter into groundwater. Pesticides can be washed into water bodies by rainwater or may enter them directly if they are sprayed close to water. Pesticides can also enter groundwater via soil infiltration. In addition, erosion can wash topsoil into water bodies which can carry large amounts of phosphates and agri-chemicals that are bonded to clay particles.

As in 2019, 36% of surface water bodies assessed under WFD in the UK were in ‘high’ or ‘good’ status in 2020. Diffuse water pollution from agriculture and rural land use has been directly attributed to 28% of failures to meet the WFD standards in England ^{[footnote 7]}.

Figure 11.11 UK surface water bodies under the water framework directive

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year	High	Good	Moderate	Poor	Bad	Total (excluding unassessed)
2009	4%	32%	48%	13%	3%	100%
2010	4%	32%	47%	13%	3%	100%
2011	4%	33%	45%	15%	3%	100%
2012	4%	33%	45%	15%	3%	100%
2013	4%	32%	44%	16%	3%	100%
2014	3%	32%	45%	17%	3%	100%
2015	4%	31%	47%	15%	2%	100%
2016	5%	30%	47%	15%	3%	100%
2017	5%	30%	47%	14%	3%	100%
2018	5%	31%	47%	15%	3%	100%
2019	5%	31%	47%	14%	3%	100%
2020	5%	31%	48%	14%	2%	100%

Notes:

1. Based on numbers of surface water bodies classified under the Water Framework Directive (WFD) in England, Wales, Scotland and Northern Ireland. Includes rivers, canals (Northern Ireland does not report on canals), lakes, estuaries and coastal water bodies.
2. A water body is a management unit, as defined by the relevant authorities.
3. Water bodies that are heavily modified or artificial (HMAWBs) are included in this indicator alongside natural water bodies. HMAWBs are classified as high, good, moderate, poor or bad ‘ecological potential’. Results have been combined; for example, the number of water bodies with a high status class has been added to the number of HMAWBs with high ecological potential.
4. The results published each year relate to data reported in that year under the WFD; data reported in a given year relate to data collected over the previous year (for Scotland) and previous 3 years (for England, Wales and Northern Ireland).
5. From 2016, England, Wales and Northern Ireland have moved to a triennial reporting system. Wales and Northern Ireland reported in 2018 and whilst due to report in 2021, the data was not available in time for this publication; England reported in 2016 (classifications carried forward for 2017 and 2018) and 2019. The most recent classification for England was in 2019 and therefore these classifications have been carried forward to 2020. Classifications are valid until they are next assessed; therefore, for years where a country does not report, their latest available data are carried forward.
6. Percentage of water bodies in each status class has been calculated based on the total number of water bodies assessed in each year. Totals may not agree due to rounding.
7. The number of water body assessments included varies slightly from year to year.
8. The reductions in the number of assessments made in 2015 and 2016 were primarily due to Wales and then England adopting the monitoring and classification standards laid down in Cycle 2 of the WFD. This resulted in the removal of a number of water bodies that were below the 10km2 catchment area in line with WFD guidance. It also means that data from 2015 onwards are not directly comparable to those in earlier years.

Source: UK Biodiversity indicators

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Further information on classifcation of water bodies

Biodiversity

Bird populations are considered to be a good indicator of the general state of wildlife as they have a wide habitat distribution, are near the top of the food chain and are able to be monitored over time as long-term datasets are available for the UK. Agriculture provides valuable resources for farmland bird populations in terms of winter food, spring forage and nesting habitats.

The farmland bird index comprises 19 species of bird. The long-term decline of farmland birds in the UK has been mainly driven by the decline of the 12 species known as the ‘specialists’ that are restricted to, or highly dependent on, farmland habitats (see Figure 11.12). Between 1970 and 2021, populations of farmland specialists declined by 71% whereas farmland generalists have declined by 13%. The 2021 index for all farmland bird species was 56% less than its level in 1970.

The largest declines in farmland bird populations occurred between the late 1970s and early 1990s due to the impact of rapid changes in farmland management. Whilst agri-environment schemes offer specific measures designed to help stabilise and recover farmland bird populations, the situation is complex with other pressures such as weather effects and disease pressures adversely impacting some species.

Figure 11.12 Farmland Bird Index (1970 = 100)

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Source: Wild bird populations in the UK

Text description for Figure 11.12: Figure 11.12 is a line chart showing the farmland bird index for specialist species, generalist species and all farmland birds from 1970 to 2021. In this indexed chart, 1970 = 100. The chart shows that all birds and specialist species have shown a steady decline over time and populations in 2021 were under half of 1970 levels. Generalist species have shown less of a decline, with populations approximately 10-20% less than 1970 levels.

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Further information on the farmland bird index.

1. Total costs of soil degradation project 2011 Defra ↩ ↩²

2. Controlling Soil Water Erosion and Phosphorus Losses from Arable Land in England and Wales, Chambers et al. 2000 ↩

3. Time of sowing and the yield of winter wheat, Green et al, 1985 ↩

4. Updating an estimate of the sources of nitrogen to waters in England and Wales. Defra project WT03016.Hunt, D.T.E., et al, 2004 ↩

5. Updating the estimate of the sources of phosphorus in UK waters. Defra project WT0701CSF. White, P.J. and Hammond, J.P., 2006 ↩

6. The impact of phosphorus inputs from small discharges on designated freshwater sites. Report to Natural England and Broads Authority, SWR/CONTRACTS/08-09/112.May, L., et al, 2011 ↩

7. POSTnote 478 October 2014 Diffuse Pollution of Water by Agriculture, 2014 ↩