European Fertil izer Manufacturers Association
SU S TA I N A B L E S O I L M A N A G E M E N T
A N A C H I E VA B L E G O A L
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European Fertil izer Manufacturers Association
SU S TA I N A B L E S O I L M A N A G E M E N T
A N A C H I E VA B L E G O A L
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Sustainability ...................................................................................................................................................................................... 3
Towards sustainable agriculture in Europe ....................................................................................................................... 4
The importance of the soil ........................................................................................................................................................ 7
Soils under stress.............................................................................................................................................................................. 9
Sustainable soil management .................................................................................................................................................17
Conclusion......................................................................................................................................................................................... 25
Sources and recommended further references ........................................................................................................... 26
TABLE OF CONTENTS
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S U S TA I N A B L E S O I L M A N A G E M E N T
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SUSTAINABILITY
It was as chair of the World Commission on Environment and Development that Dr Gro
Harlem Brundtland, the former Prime Minister of Norway, in her 1987 report to the United
Nations, introduced us to the word 'sustainabil ity'. The report, Our Common Future, came to
be known as the Brundtland report, and the term sustainabil ity became an international
aspiration, giving the world a focus and a common goal to work towards. Since that time,
nat ional , European and internat ional bodies have been reminding us of our jo int
responsibil ity to l ive our l ives in a way that does not jeopardise the chances of future
generations to l ive their l ives, and they continue to propose guidelines or introduce
regulations to that end.
The Brundtland report inspired the United Nations Conference on Environment and
Development (UNCED) ‘Earth Summit’ in Rio in 1992, which produced Agenda 21, a
declaration concerning agriculture and rural development. In Agenda 21, the Earth’s capacity
to satisfy the demands of a growing population was examined. Major adjustments in
agricultural, environmental and macroeconomic policy were recommended, with a view to
creating the conditions for sustainable agriculture and rural development (SARD). It was
suggested that production should be increased mainly on land already in use and that further
encroachment on land that is only marginally suitable for cultivation should be avoided.
Agriculture as an economic sector was a major focus for the UN Commission on Sustainable
Development in 2000, when the major objectives of increasing food production and
enhancing food security in an environmentally sound way were reaffirmed. It was noted that
although food security for al l countries is a policy priority, it remains an unfulfi l led goal.
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TOWARDS SUSTAINABLE AGRICULTURE IN EUROPE
PoliciesIn its 1999 document Towards Sustainable Agriculture , the European Commission noted the
significant l ink, throughout the EU, between agriculture and the conservation of the
environment. It also pointed out that while the intensification of agriculture had, in some
areas, accelerated erosion, in other areas, the abandonment of farmland had reduced the
diversity and aesthetic value of the countryside. The document also explained the concept of
‘cross-compliance’ contained in the reform of the Common Agricultural Policy that was
adopted in 1999, whereby direct payments are to be l inked to environmental programmes
and farmers reimbursed for environmental services that exceed the requirements of Good
Agricultural Practice.
Responding to a request from the European Council , in
January 2000, the Commission published a report entit led
Communicat ion on Indicators for the Integrat ion of
Environmental Concerns into the Common Agriculture Policy .
In this document, in a section on land use and soil, it is stated
that erosion should be countered, adequate farming systems
promoted, soil surface nitrogen balances improved and the
destruction of landcover reduced.
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Practical ways forwardIts soils and cl imate make Europe a particularly ferti le and productive food-growing region,
and the population of Europe has an important role to play in safeguarding the ferti l ity and
food-growing potential of its lands. Often called the caretakers of the land, farmers are in
the spotl ight when such responsibil it ies are discussed. While farmers certainly play a major
part in caring for the land, al l of us – whether we are farmers, consumers, agronomists, policy
makers or supply industries – have a shared interest in, and commitment to, safeguarding the
wellbeing of the land.
As members of an important agricultural supply industry, the European manufacturers of
mineral ferti l izers, represented by EFMA, are major stakeholders in agriculture. The farmer’s
main asset, the soil, is the basis of our existence, and a policy of responsible care that
maintains a healthy farming sector with healthy soil is the key to our survival. By undertaking
to supply agriculture with high-quality plant nutrients, by maintaining and further developing
clean, energy-efficient production processes, and by promoting the sustainable use of its
products, the members of EFMA make an active contribution to sustainable agriculture.
One of EFMA’s main activit ies is the investigation of the interrelation of
agriculture and the environment, in order to establ ish and promote Best
Management Practices in agriculture.
EFMA firmly supports the concept of Integrated Plant Nutrit ion (IPN), which
emphasises the importance of ferti l izer planning at the
farm level and promotes the use of al l the nutrients
available on a farm to the best advantage of the farm’s
cropping system. EFMA also supports Integrated Crop
Management (ICM), which combines, on a whole-farm
basis, the aims of producing food in an efficient and
economical way and conserving finite resources and
protecting the environment at the same time.
To th is end, EFMA promotes a Code of Good
Agricultural Practice: Nitrogen , which is based on
principles such as the Nitrogen Budget, the Ferti l izer
Plan and Ferti l izer Practice for Water Protection, and a
Code of Best Agr icultural Pract ice: Urea , which
provides guidelines for the effective use of urea on
agricultural crops under European conditions.
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As an experienced industry that has been gathering knowledge about the interaction of its
products with specific crops, soils and cl imates for many years, the European ferti l izer
industry has been able to develop comprehensive decision support systems for farmers and
agricultural advisers. EFMA is able to draw on the industry’s knowledge of plant nutrit ion
and soil ferti l ity to identify and promote solutions for good management practices for the
future.
6
▲ Fertile soil is precious and the farmer's main asset.
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THE IMPORTANCE OF THE SOIL
Soils are the point of interaction between the two basic processes in ecosystems: production,
the generation of biomass by green plants, and decomposition, the subsequent breakdown of
this biomass. In the l ives of plants, animals, microorganisms and people – but also in energy,
water and material budgets – the soil fulf i ls several important functions, which are described
below.
Habitat functionSoils provide a habitat and the means of survival for a wide variety of plants, fungi, animals
and microorganisms. The metabolism of these organisms is the basis for the regulation function
and the production funct ion of soi ls (see below). Soi l organisms are responsible for
transforming organic substances in soils, added to which they play a major role in stabil is ing
ecosystems and make an important contribution to biodiversity. Soils provide plants with their
rooting medium and serve as a supplier of water, oxygen and nutrients. They are therefore the
basis for the primary production of terrestrial systems and, at the same time, for al l higher
organisms in the food web, including human beings. In addition, soil is a habitat for people,
for whom land represents ‘territory’ that they inhabit and uti l ise.
Regulation functionSoils regulate the exchange of substances between the hydrosphere and the atmosphere. They
act as a buffer for acids, and they fi lter substances from rainwater, infi ltration water and
groundwater. The soil provides storage capacity for water, nutrients and harmful substances,
and at the same time it recycles nutrients, detoxifies harmful substances and destroys
pathogens.
Util isation functionThe soi l is also said to have a uti l isation function, which can be divided into two main
subfunctions :
Production function
As consumers of vegetable and animal foods, people are ‘consumers’ of soils, and, with the
steady increase in population growth, the uti l isation of soils for agricultural and forestry
production has become increasingly important for human society. In addition to agriculture, a
further production function is the exploitation of natural resources such as coal, oi l , gas, peat,
sand, gravel, rocks and minerals. The extraction of these raw materials usually involves the
destruction of soils.
Carrier function
The term 'carrier function' is used to refer to the use of the land for settlements, transport,
supply and disposal, for industrial and commercial production and for the disposal of waste.
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Cultural functionThe preservational properties of soils mean that they are an ‘archive’ for natural and cultural
history, tel l ing us much about our past. Many soils have been cultivated by farmers for
centuries, and there is an increasingly strong movement in favour of preserving this cultural
heritage in Europe.
Global aspects of soil functionsThe functions of soils that are considered to be particularly important from the global
perspective are:
Habitat function
- Soils contribute to biodiversity
- Soils represent a genetic pool
Regulation function
- Soils influence the exchange of radiation
- Soils regulate the hydrological cycle of the continents
- Soils are stores and transformers of nutrients
- Soils are sources and sinks for carbon dioxide and methane
- Soils are sources of nitrous oxide
- Soils are buffers, f i lters, transformers and stores for pollutants
- Soils are sources for the contamination of neighbouring environmental compartments
Utilisation function
- Soils form the basis for food production
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SOILS UNDER STRESS
L ike air and water, the soil is a precious resource. However, it is not an unchanging resource.
On the contrary, the quality and quantity of soil in any one location can change markedly in
a relatively short t ime-span. Such changes may result from human activit ies, from natural
processes or from a combination of the two.
The European Commission recently published a report on soil degradation in the EU
(Agriculture, Environment, Rural Development: Facts and Figures - A Challenge for
Agriculture, EUROSTAT, 1999). This report suggests that among the various forms of soil
degradation, soil erosion in particular is a serious problem in the EU, with more than half the
land in Europe having suffered various degrees of erosion by water and about a fifth having
been eroded by wind. The problem is at its most acute in some parts of the Mediterranean
region, where erosion has resulted in the exposure of extensive areas of bare rock. Although
the historical effects of erosion can be beneficial (many of today’s best agricultural soils are
deposits of formerly eroded material) the displacement of soil by water and wind is, at
present, robbing the farmer of his main asset and reducing the farming opportunities of
future generations. Erosion can also trigger environmental problems.
Soil in movementMany people associate erosion with arid, windswept regions of the world or with areas of
former rain forest, where heavy rains on unprotected, hil ly land can cause catastrophic
instances of erosion. However, European soils are also being eroded. Managed in an
inappropriate way or abandoned, soils in some areas may experience a reduction in quality
and quantity that renders them inferti le – in some cases, irreversibly so.
What exactly is erosion and how does it occur? Rainfall is the most common cause of erosion.
With an impact of up to 30 mph, rain can easily displace soil. In general, the occurrence of
water erosion depends on factors such as climate, topography and soil characteristics. Runoff
occurs when rain falls at a rate that exceeds the soil’s capacity to absorb water and the
gradient of the land allows water and soil to flow downhill. In Northwest Europe, where rain
falls on gentle slopes in the main and is fairly evenly distributed throughout the year, rates of
erosion average 0.24 t/ha a year. In the mountainous regions of France, losses range from 1.8
to 2.5 t/ha a year, while in small valleys in the Alps and the Apennines, losses can reach 25
t/ha a year.
Sometimes, soil is removed from sloping land in thin layers, a phenomenon known as sheet
erosion. The most common form of erosion by water, however, is rill erosion. This occurs
when soil is removed by water running in small streams through land with poor surface
drainage. It is common for ri l ls to form between vertical crop rows, though the farmer can
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often be unaware of the process since its effects are easi ly
covered up by ti l lage. A more advanced form of ri l l erosion is
gully erosion . Gull ies can cause substantial damage to fields
and cannot be corrected by ti l lage.
Wind erosion can occur even on flat land if the land has no
vegetative cover and is dry. When particles of fine si lt or clay
and organic matter are transported by the wind, they carry the
nutr ients they have absorbed with them. This se lect ive
displacement of soi l mater ial leaves behind impoverished,
coarse-textured soil particles.
Environmental damage caused by wind erosion includes the
pollution of the air by fine dust particles and the covering of
ferti le land with inferti le deposits. In extreme cases, productive
land can be buried under dunes. Water erosion, on the other
hand, can – in addition to reducing soil quality and productivity
– carry phosphorus into bodies of fresh water, which can
increase the risk of eutrophication , or the over-enrichment of
water with nutrients. In areas with high accumulations of
nutrients in the soil because of the excessive application of
animal manure or the inappropriate use of mineral ferti l izers,
nutrients are more prone to leach into groundwater or rivers or
be carried overland with run-off to nearby surface waters.
Nutr ient-r ich waters can resul t in a h igher-than-average
growth of algae, the decomposition of which can lead to
oxygen starvation in the water, ki l l ing fish and other aquatic
l ife forms.
Soil under pressureAnother form of soil degradation is compaction, which occurs
when soil particles are compressed by heavy machinery or the
trampling of animals. Compaction reduces the soil's porosity, and
when this happens, plant roots are less able to penetrate the soil.
In addition, water drainage and air diffusion are restricted. Wet
clays are more susceptible to compaction than sandy soils. The
negative effects of soil compaction can be remedied to varying
degrees depending on the structural damage, by using special
til lage techniques to break up the soil.
10
▲ Gully erosion
▲ Wind erosion
▲ Bad timing and inappropriate equipmentdamage the soil's structure.
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AN ACHIEVABLE GOAL
Soil without lifeIn some dry regions of the Mediterranean area, the
removal of vegetation started a process that has
ended in desertification . The vulnerable soil surfaces
of such regions have l itt le organic matter and a
reduced capacity to store water, thus exposing them
to further erosion processes. The affected regions
seldom recover any vegetation and thereby become
part of the 40% of the Earth’s surface composed of
drylands susceptible to desertif ication (UNEP Global
2000). Today, more than 1,000 mil l ion people are
affected by soil degradation in such areas of the
world.
Soil out of balanceOther forms of soil degradation are the result of chemical changes in the soil’s composition.
Acidification , for example, occurs naturally as a result of acidifying deposits from the
atmosphere and microbial activity in the soil. Intensive industrial isation and the burning of
fossi l fuels produce acidifying emissions, thus exacerbating the problem. Acidification
reduces the availabil ity of nutrients such as phosphorus to plants, it increases aluminium
toxicity, and it adversely affects the physical and microbial condition of the soil. Regular
l iming is required to counter these adverse effects.
Salinisation , the accumulation of salts on or near the surface of the soil, is a process that
results in completely unproductive soils and which currently affects nearly 4 mil l ion hectares
of land in Europe, mainly in the Mediterranean region and in East European countries. It is
particularly common on irr igated soils in hot regions, where water tends to evaporate before
it has time to seep into the soil. A common solution, but one that is expensive and cannot
be considered sustainable, is to over-irr igate, applying more water than the crop can use.
Serious changes in the soil’s chemical composition can take place when nutrients are
removed from the soil by repeated harvests and are not replaced by organic or mineral
ferti l izers. When the soil’s nutrient status and ferti l ity are reduced in this way, soil mining is
taking place. The same phenomenon can be observed with soil organic matter: inappropriate
soil management and crop sequences may exhaust the organic matter content of the soil,
having negative effects on soil structure, water and nutrient storage capacity and water
drainage. Finally, excessive accumulations of potential ly hazardous substances can lead to
contamination of the soil.
11
▲ Desertification is widespread in part of southernEurope.
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Soil mining and acidification can both have serious environmental consequences in that they
result in the inexorable deterioration of soil ferti l ity and, subsequently, in a decline in soil-
fixing root development and plant growth. This greatly enhances the risk of erosion.
Global issue: soil management and climate changeEmissions of carbon dioxide and nitrous oxide, which increase the concentration of
greenhouse gases in the atmosphere, can be caused by soil degradation, deforestation, soil
drainage or ploughing. Soil compaction also increases emissions of nitrous oxide by creating
areas that are deficient in oxygen. Enhancing the efficiency of nutrients in soil and
ferti l izers, and preserving or building up the organic matter content of the soil acts as a
counter measure. The conservation of organic matter in the soil creates a sink for carbon
dioxide, which is a welcome soil function in the context of cl imate change.
On the other hand, excessive amounts of organic matter in the soil also increase the risk of
nitrous oxide forming under oxygen deficiency conditions. Conversely, under oxygen-rich
conditions, microbes become particularly active in breaking down organic matter, which
increases the risk of carbon dioxide being released. The potential emission of these
greenhouse gases as an effect of soil degradation and soil management has to be taken into
account by policy makers and farmers, particularly when sudden changes in soil management
(e.g. the introduction of set-aside and abandonment of ferti le soils, the ploughing of old
grassland areas, or the cultivation of moors) are considered.
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When agricultural soils are badly managedS ince over three-quarters of the territory of the European Union is agricultural and wooded
land (44% agricultural land, 33% wooded land; EC, 1999), agriculture has a significant
impact on European soil.
Certain agricultural practices can effectively increase the risk of soil degradation.
Examples of bad management practices include:
• depleting vegetative cover
• damaging the soil structure
• farming land that is unsuitable for the purpose
• excessive levels of manure
• depleting soil resources (i.e. organic matter and nutrients)
• mismanaging irr igation
• damaging watercourses
Depleting vegetative cover creates opportunities for
surface erosion by strong winds or heavy rains. The
effects are particularly noticeable when bare, dry soil
that is weak in structure is exposed by the burning of
straw after the crop has been harvested, or when
pasture is overgrazed by l ivestock.
The use of heavy machinery on wet, loamy soils, and
overgrazing or trampling by l ivestock can damage the
soil’s structure by compaction. Activit ies such as
continued cropping with excessive soil t i l lage cause
rapid decomposition of the soil’s organic substance.
Lime needs to be added to soil not only to neutral ise
acidification but also to stabil ise the soil particle
cohesion and structure. It is important to note that acidif ication also occurs on abandoned
land and in forest regions. It is, moreover, interesting to note that regional marginalisation
and the abandonment of land, as with set-aside, though often thought to be environmentally
beneficial practices, can in fact accelerate soil degradation in previously ferti le land. In areas
with a dry cl imate, this can also lead to desertif ication.
Hil ly, forested areas have been, and continue to be, converted into agricultural land,
particularly in tropical regions. Such areas are often unsuitable for farming . Heavy rainfall
and a warm climate quickly degrade the upper layers of the soil, mainly through erosion and
13
▲ Erosion in neglected olive plantation.
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microbial breakdown of soil organic substance. But also under less extreme cl imatic
conditions, as in western Europe, growing maize in hil ly areas (often former grassland), for
example, has caused huge soil losses by erosion. In Mediterranean countries, old olive
plantations in hil ly areas have been cleared, leaving the soil exposed, and where they have
been replaced, it has been by less suitable crops. This is leading to extensive erosion and soil
losses in southern Europe. Furthermore, the over-intensive use of pasture by high densities
of l ivestock causes erosion in many hil ly regions of Europe.
In areas with a high density of l ivestock (the Netherlands, parts of northern Germany,
Belgium, northern France), the amount of manure produced is far too high for it al l to be
used on the available land. However, since transportation of these wastes to other areas with
lower l ivestock populations is costly, local soils have been receiving excessive levels of
manure for many years. This practice has resulted in high regional accumulations of organic
matter and nutrients beyond the level that can be retained by the soil. The same effect can
be caused by the over-application of manufactured ferti l izers. Microbiological functions can
suffer severely and might take decades to recover.
Economic or regulative pressures can force farmers to mine the soil, meaning that they
deplete its reserves by fai l ing to replenish resources in l ine with crop yield and crop quality
parameters. Consequently, in the long run, losses in yield level and quality are predictable,
since the soil is being progressively worn out. Once a crit ical ly low nutrient level in the soil
has been reached, only high applications of ferti l izer wil l gradually build up soil ferti l ity to
previous satisfactory levels. Long-term experiments show that this soil recovery process can
take decades.
Long-term experiments have also demonstrated that without appropriate applications of
ferti l izer, a decline in the soil nutrient status, in soil ferti l ity (yield), soil coverage can occur.
There is a l ink between soil ferti l ity and erosion, which would suggest that al lowing nutrient
reserves to become reduced could have a seriously detrimental effect on agricultural land.
Mismanaging the application of water in agriculture can cause soil degradation in different
ways. Too much water can cause losses of soil substance in the form of runoff ( i.e. water
erosion). In arid and semi-arid regions, however, irr igation practices often fai l to keep pace
with natural leaching, thereby causing salinisation. Finally, al lowing grazing cattle to have
access to natural watercourses can cause banks to break down, thereby damaging water
courses and allowing erosion to set in.
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Lack of awareness regarding soil degradation in EuropeIt is more often a lack of information about soil erosion than
consc ious malpract ice that leads to neglect of the land.
Economic, and sometimes regulatory, pressures can also have an
effect. Regulatory mechanisms such as the removal of olive trees
as a precondition for set-aside, for example, have been known to
cause problems of erosion, especial ly when the planting of
substitute crops is not foreseen.
There are numerous community-wide init iatives and programmes
at the regional and national level which have a bearing on the
protection of the soil. The first step in preventing or controll ing
further damage from different forms of soil degradation is to
monitor the processes that occur and to analyse and assess
potential r isks in the various regions of Europe.
Assessing the riskGenerally, the risk of soil degradation is present throughout the
European Union. Symptoms can be found in v i r tua l ly a l l
agricultural regions and production systems. Some regions are
particularly vulnerable to erosion for cl imatic and topographic
reasons, while other areas have received high applications of
l ivestock manure, resulting in high organic matter and nutrient
accumulations that can lead to polluting emissions and disturbed
microbiological processes in the soil.
The potential r isk of erosion arising from the removal or lack of protective vegetative cover
is significant, even on gently sloping land, and considerably exceeds the tolerance level. In
Belgium, for example, 10% of agricultural land is considered to be susceptible to water
erosion. In extreme cases, rates of soil loss as high as 82 t/ha a year have been reported on
bare fal low land with 5-7% slopes. Water erosion is also the dominant form of soil erosion
in France, where it affects about 5 mil l ion hectares of agricultural land (about 17% of the
total). In fact, soil erosion is reported to affect most of the main cereal growing areas in
France.
In the Mediterranean region, cl imate, strong rel ief (characterised by steep slopes and
exposure to the elements) and a long history of human interaction with the natural
ecosystems have resulted in high rates of soil erosion more frequently than in other regions
of the continent.
15
▲ Manure application needs to betailored to the specific site and crop.
▲ Over-irrigation can cause erosion.
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According to the results of the CORINE assessment
(1992), about 66% of the rural area displays a
moderate to high potential r isk of soil erosion by
water. The distribution of the risk in the region, and
within the individual countries, is complex. A large
proportion of land in Portugal, Greece and Spain
(68%, 43% and 41% respectively) is at high risk
from soi l eros ion, whereas the corresponding
proportions in Italy and in Mediterranean France are
less (27% and 9% respectively).
High-risk areas, which due to their gradient and
climate could experience soil erosion, are to be found
in the Pyrenees, the Alps, the Apennines and the Pindos mountain
range. Also at r isk are areas of rugged terrain throughout
Portugal, in Southeast Spain, in Corsica, in Sardinia, Calabria and
Sici ly in Italy, and in Crete and the Aegean Islands in Greece. The
area currently at r isk from erosion, given the present vegetative
cover, is considerably smaller than the area of potential r isk and
is estimated to cover 30% of Portugal, 29% of Spain, 1% of
Mediterranean France, 10% of Italy and 19% of Greece.
Information on the extent and severity of desertif ication in
Europe is l imited, though the United Nations Convention to
Combat Desertif ication (UNCCD), in its Regional Implementation
annex (Annex IV), addresses the extensive desertif ication phenomena of the northern
Mediterranean countries.
Research and data collection on the status of European soils has been undertaken within the
EU by the European Soil Bureau (ESB) of the Joint Research Centre in Ispra, Italy and by the
European Environment Agency. Work has also been carried out by international organisations
such as the European Society for Soil Conservation (ESSC) and the European Conservation
Agr icu l tura l Federat ion (ECAF), and by regional assoc iat ions l ike CIDE (Centro
Investigaciones Desertif ication).
16
▲ Rain simulation and erosion measurement.(University of Bonn)
▲ Furrow irrigation in Spain.
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SUSTAINABLE SOIL MANAGEMENT
Understanding the processSafeguarding the quality and quantity of European soils requires active soil management.
For this to be successful, those involved in the management of the soil must have a thorough
understanding of the geology, topography and cl imate of the area they are caring for.
Although it is possible to make regional generalisations about soil to some extent, accurate
assessments can only be made if soil conditions are ascertained at the farm level, where
there can even be differences between one field and another. Some of the methods currently
used to sustain the quantity and quality of agricultural soils are techniques that have been
practised for centuries, while others are newer techniques, developed as a result of more
recent advances in science and technology. The use of mineral ferti l izers combined with soil
analysis techniques to supplement the organic nutrients available on farms is an example of
scientif ic advances that have led to greater precision in farming and protection of the soil.
Active soil management, based on a thorough knowledge of the area concerned and
motivated by the desire to sustain the quantity and quality of the soil, leads us to seek the
most appropriate use for a given area of land. Where the soil is stable, ferti le, cultivated and
managed in a sustainable way – by ensuring the replenishment of organic matter and plant
nutrients to compensate for the plant matter and nutrients that are removed with the
harvested crop – we are l ikely to continue agricultural activity. Where, however, soils are less
stable, less ferti le or less well suited to certain forms of agricultural production, we need to
manage the soil differently or identify a more appropriate use for the land. This may lead us
to take one of the following decisions:
a) to leave the land, making an active decision not to interact with it
b) to take protective measures designed to prevent potential imbalances or site-specific
problems
c) to take counter measures to reverse crit ical situations
Identifying solutionsHaving assessed the risks of soil degradation and identif ied the regions affected, the next
step in implementing sustainable soil management is to identify site-specific solutions to the
current problems. Agriculture has a key role to play in this process, much of which has to do
with protecting ferti le soils.
Productive agricultural soils are a precious and l imited resource, but increasing global food
demand wil l ult imately force al l regions of the world with high soil ferti l ity and a favourable
cl imate, such as Europe, to contribute to and take responsibil ity for meeting global food
demands.
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The outstanding yield levels of European agriculture are based on intensive farming methods
that make use of appropriate and highly efficient inputs. Only ferti le, healthy soils can
sustain such yield levels, and nutrients removed with the harvested crops have to be
replenished accordingly. Thus, in intens ive farming, susta inable land use and the
maintenance of soil ferti l ity are major challenges for farmers. Land that is under intensive
cultivation needs careful management, but also marginal and set-aside lands require good
care in order to combat soil degradation and to maintain long-term farming options for
future generations.
Sustainable soil management measures designed to avoid degradation and to maintain soil
ferti l ity are based on Best Management Practice (BMP).
Best Management Practice involves:
• protecting soil structure and organic content
• managing nutrients
• conserving the soil with plant cover
• planting forests
• maintaining the ferti l ity of the soil
• using advanced techniques such as fertigation
• applying appropriate cultivation techniques
18
Wheat yield in tonnes per hectare in key producing countries, 1999(FAO, 2000)
United Kingdom 8.0
France 7.2
Egypt 6.3
Mexico 4.8
China 4.0
Poland 3.5
United States 2.9
Ukraine 2.3
India 2.6
Argentina 2.5
Canada 2.6
Pakistan 2.2
Australia 1.8
Russia 1.3
Kazakhstan 1.3
soil.mep 30/04/01 12:01 Page 18
AN ACHIEVABLE GOAL
19
Best Management Practice (BMP) - the conceptBest Management Practice (BMP) describes the concept of combining soil management
practices and other agricultural management practices to arrive at the most effective and
economic way to avoid soil degradation. In the case of erosion control, these practices
include reducing physical and chemical stress to soils (e.g. protecting the soil against
raindrop impact), reducing runoff, restricting runoff velocities, and avoiding the use of
heavy machinery at t imes when the soil is vulnerable.
Protecting soil structure and organic matterThe structure of the soil is determined by the size of the soil particles, their distribution and
the organic matter content in the different layers of the soil. The spatial distribution of the
soil particles determines the volume of the soil’s pores and, therefore, its oxygen and water
storage capacity and availabil ity. Ferti le soils have a rather l ight structure, ensuring good
water drainage and storage and the availabil ity of oxygen. They work l ike a sponge, storing
and then slowly releasing water. The organic matter content can be regulated by applying
livestock wastes or by incorporating straw. On grassland, organic matter is built up with the
accumulation of root remains.
Managing nutrientsThe abil ity of soils to store and release nutrients depends on their structure, organic matter,
mineral content and particle size fractions. Water content is particularly important for the
mobil ity of nutrients, while the pool of organic matter that has been built up over
generations can act as a source or a sink for
nutrients, accumulating or releasing them into the
soil solution or atmosphere. Soil analysis and soil
t i l lage are some of the instruments that enable
farmers to manage the nutrients that are found in
the soil’s reserves. Manufactured ferti l izers serve as
a targeted supplement to the farm’s own resources,
which often take the form of l ivestock manure.
▲ Soil sampling to assess the soil's nutrientreserves
soil.mep 30/04/01 12:01 Page 19
SUSTAINABLE SOIL MANAGEMENT
Successful nutrient management
impl ies matching the nutr ient
supply in the soil to the nutrient
requirements of each crop,
supplying any shortfal l in the
form of organic or minera l
fert i l i zers . In th is way, the
nutrients that are taken up by
crops and removed dur ing
harvesting are replaced (Good
Agricultural Practice: Nitrogen,
EFMA, 1997; Code of Best Agri-
cultural Practice: Urea, EFMA,
2000). When added in a
responsible manner, nutrients in
the form of manufactured or organic ferti l izers increase the
quantity and quality of the crops and maintain or improve soil
ferti l ity while avoiding oversupply and losses.
Conserving the soil with plant coverP lants protect soils from erosion, both above and below ground. Above ground, the stems and
leaves act as protective barriers, preventing wind and water from eroding the soil, while below
ground, plants reduce erosion by binding and anchoring soil particles with their roots. Crop
residues also help to prevent erosion by absorbing the energy of raindrops, thereby reducing
soil splash. In short, plants and close-growing crops minimise raindrop impact, hold the soil
together and act as a fi lter, while crop residues, plants, rough soil surfaces, and gradual slopes
help spread the flow of water over a wider
area, thereby reducing the velocity of the
runoff.
Typical cover crops include grass, legumes or
small grains grown between regular production
periods or between the rows of the main crop
for the purpose of protecting and improving
the soil. To control water erosion, winter cover
crops are planted that hold the soil together
unt i l the spr ing, thereby help ing to keep
nutrients in the soil and reduce run off. Cover
crops a lso protect the land against wind
erosion. It should be noted, however, that the
20
Timing of fertilizer application and ▲
exact calibration are essential in order to
achieve good yields and high quality.
▲ Grass covers the soil between maize rows.
soil.mep 30/04/01 12:01 Page 20
AN ACHIEVABLE GOAL
21
cultivation of cover crops is often restricted in areas with a l imited water supply (e.g.
southern Europe).
Planting forestsIn those Mediterranean areas where the risk of erosion is high, the planting of forests is an
appropriate practice to aid soil conservation. Experiments indicate the advantages of
ferti l izer use in speeding up the growth of young trees in order to establish forests.
Maintaining the fertil ity of the soilS ince industrial isation and the discoveries that led to a better understanding of plant
nutrit ion and the means to produce mineral ferti l izers, farmers have had increasing access to
manufactured ferti l izers, which has enabled them to continuously improve soil ferti l ity and
crop yields. Scientif ic research and the transfer of modern crop husbandry knowledge into
practical applications have brought about huge improvements in agricultural productivity. As
soil ferti l ity has been built up, rural development and l ivestock production have become
possible even in hil ly areas that were previously impoverished.
The current levels of soil ferti l ity in Europe were built up mainly during the last few decades.
Thanks to improvements in seed and in crop management, annual wheat yields are sti l l
increasing by about 100 kg a hectare on average. The good nutrient and organic matter
content of many soils in the EU means that ferti l izer input can be closely adapted to
expected yields, resulting in the efficient use of inputs.
Manufactured ferti l izers can be applied exactly
when the crop needs nutrients the most, and
the amount of nutr ients appl ied can be
precisely controlled. Soil testing indicates the
nutrient status of the soil, and farmers and
advisory services are increasingly employing
special ly developed computer programmes to
calculate nutrient needs. In addition, chemical
and, increas ingly, opt ica l p lant analys is
methods are being applied. Many farms have
experience of using mineral fert i l izers that
stretches back more than thirty years.
After the decades spent on building up Euro-
pean so i l fer t i l i ty, fert i l i zer consumpt ion
decreased drastical ly in 1992, when set-aside
was introduced as a polit ical instrument to control agricultural surpluses. It has continued to
decrease as a result of increased efficiency in nutrient use – also from livestock sources – and
8
6
4
2
0
10
12Nutrient (million tonnes)
N P2O5 K2O
1925 1935 1945 1955 1965 1975 1985 1995 2005
Development of fertilizer nutrient consumption in the EU(EFMA)
soil.mep 30/04/01 12:01 Page 21
S U S T A I N A B L E S O I L M A N A G E M E N T
because of continued progress in cropping systems. However, the trend towards reduced
ferti l izer use in European agriculture needs to be monitored closely, since in the longer term,
nutrient deficiencies may affect the health and quality of crops as soils become exhausted.
On mined or abandoned areas, where there is often less plant cover and, as a result, less
protection for the surface of the soil, soil ferti l ity and soil structure may suffer further. Soil
degradation and erosion problems could increase, especial ly in those southern European
regions where it is less easy to achieve plant cover to protect the soil.
Using advanced techniques such as fertigationDrip irr igation, a technique that provides crops with water through special pipes at a high
frequency but with a low volume of water (drips), can be combined with ferti l izer
appl icat ion, to offer fert igat ion. I t i s a technique that i s
part icu lar ly appropr iate in dry zones, for example in the
Mediterranean region. Fertigation enables the farmer to meet the
specific water and nutrient needs of the crops with great precision,
thus minimising losses of both precious water and nutrients.
A beneficial side effect of fertigation is the avoidance of soil
erosion and soil degradation, in that it el iminates the use of heavy
machinery that can cause soil compaction. In addition, less water
is needed to produce 1 kg of dry matter, since the water supply
can be adapted to the speed of infi ltration, thereby avoiding
surface runoff and erosion. Fertigation al lows cover crops or
spontaneous vegetation to be grown in between rows of trees,
with pos i t ive effects on so i l conservat ion. Moreover, th is
technique faci l itates the growing of trees on slopes, thereby
making a further contribution to the prevention of erosion.
In humid regions and areas with high rainfall, farmers work
actively to maintain or improve the soil’s abil ity to ‘digest‘ water.
Forming canals and instal l ing drainage pipes to remove surplus
water are common technical solutions in northern Europe. In the dry regions of southern
Europe, making use of irr igation and fertigation (i.e. combined irr igation and ferti l izer
application), improving water storage capacity, and covering the surface of the soil are
techniques used to achieve efficient water management.
22
▲ Fertigation in Spain (water andnutrients are applied drip-wisethrough pipes).
soil.mep 30/04/01 12:01 Page 22
A N A C H I E V A B L E G O A L
Using appropriate cultivation methodsCertain cultivation methods are useful as tools to combat soil erosion and other forms of soil
degradation.
Strip Farming involves planting crops in widely spaced rows and fi l l ing in the spaces with
another crop to ensure complete ground cover. In polyvarietal cultivation, the soil is planted
with several varieties of the same crop. Harvest t imes vary for the different varieties of the
crop, and since the entire field is not exposed all at once, the effects of erosion are greatly
reduced. Trees or hedges can protect against mechanical damage and the drying effects of
the wind.
The way in which a field is ploughed can also prevent
erosion. With contour farming, the soil is t i l led at r ight
angles to the slope of the land. The resulting ridges act
as dams, holding the water while it soaks into the soil
and preventing it from running down the slope, taking
soil with it. With terracing , f ields are prepared for
planting by levell ing off areas on the slope to prevent
the rapid run-off of water.
23
▲ Contour farming with maize.
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SUSTAINABLE SOIL MANAGEMENT
Through tillage the soil is disturbed prior to planting, and the timing of tilling can have a
major effect on the amount of erosion that takes place during the year. If a field is ploughed
in the autumn (and is therefore exposed to rain for long periods), erosion can occur al l
winter. However, if ground cover and the soil structure remain untouched unti l spring, the
time in which erosion can occur is much shorter.
Minimum tillage encompasses a wide range of techniques,
which include direct dri l l ing of seed into stubble or pasture,
spraying followed by direct dri l l ing, spraying followed by a
reduced number of soil t i l lage passes before sowing, and less
frequent ti l l ing. These management techniques leave substantial
crop remains in the surface layer of the soil at t imes when there
is l itt le vegetation growth. This results in a more even soil
surface, effectively reducing the risk of erosion. However, as a
consequence, ferti l izer applied to the soil surface may remain
there for a long time exposed to wind or water erosion. Careful
incorporation through ‘non-inversion ti l lage’, which disturbs the
soil without inverting, may be advisable.
As can be seen, there is a wide var iety of management
techniques and options that can be used to help combat soil
degradation and maintain soil ferti l ity. Using these techniques is clearly in the best interest
of al l European farmers, whose l ivel ihood is only ensured if they are able to practise
sustainable agriculture on healthy, ferti le soils. Once farmers are aware of the potential
problems associated with soil degradation, they are keen to follow agricultural practices that
reduce the risk.
24
▲ Sugar beets grow in soil protected bymulch.
soil.mep 30/04/01 12:01 Page 24
AN ACHIEVABLE GOAL
25
CONCLUSION
Europe’s soils are a precious and l imited non-renewable resource. Thanks to the area’s
favourable cl imate and location, and the advanced farming techniques of the European
agricultural community, the soils of Europe are extraordinari ly ferti le, providing us with high
yields in a variety of high quality food products. The provision of sufficient quantit ies of high
quality food has been based on the development and maintenance of the soil’s ferti l ity, and
this ferti l ity must be maintained if the quality and quantity of our harvests is to be sustained
in the future. The prevention of any form of soil degradation is a major responsibil ity for
both Europe as a community and for its farmers, as solutions to regional and even global
environmental problems are connected with sustainable agricultural soil management.
This document seeks to inform all those with an interest in and a commitment to European
agriculture about the problems associated with soil degradation and about the solutions to
those problems. Since tools to maintain soil ferti l ity can also prevent soil degradation,
ferti l izers, as an essential element of soil ferti l ity, have an important role to play in the
solutions suggested.
Seven steps towards achieving sustainable soil management:
1. Recognise the importance of healthy, ferti le soils
2. Assess the condition of soils throughout Europe
3. Identify site-specific problems
4. Identify site-specific solutions
5. Implement solutions/modify land management practices
6. Devise a system of incentives and support programmes to ensure that farmers achieve
sustainabil ity goals
7. Monitor progress
soil.mep 30/04/01 12:02 Page 25
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SUSTAINABLE SOIL MANAGEMENT
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AN ACHIEVABLE GOAL
Gregorich, E.G., Greer, K.J., Anderson, D.W., and B.C. Liang (1998): Carbon distribution and
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soil.mep 30/04/01 12:02 Page 27
European Fertil izer Manufacturers Association
Avenue E. van Nieuwenhuyse 4B-1160 BrusselsBelgium
Tel + 32 2 675 35 50Fax + 32 2 675 39 61E-mail [email protected]
For more information about EFMA visit the web-site www.efma.org
cover soil 2000 30/04/01 12:14 Page 1
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SUSTAINABLE SOIL MANAGEMENT
Acknowledgements
EFMA wishes to express its ackowledgments to individuals and companies for making this
publication happen. We wish to thank in particular the 'Erosion Working Group' consisting of
Dimitrios Analogides (PFI), Peter Botschek (EFMA), Sebastiàn Ruano (Fertiberia), Jane Salter
(FMA) and Hartmut Wozniak (SKW). Additional support came from Amazone, Johannes Botschek
(University Bonn), BASF, Fertiberia and SKW Piesteritz. Help in editing came from Penelope Örtli-
Barnett (eels).
Design and printing
Altitude Graphic, rue Saint-Josse 15, 1210 Brussels, (32 2 223 70 55), www.altitude.be
soil.mep 30/04/01 12:02 Page 28