20Soil%20Management%20An%20A

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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SU 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 ...................................................................................................................................................................................... 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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S U S TA I N A B L E S O I L M A N A G E M E N T

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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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

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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A N A C H I E V A B L E G O A L

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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SUSTAINABLE SOIL MANAGEMENT

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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AN ACHIEVABLE GOAL

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

9

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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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AN ACHIEVABLE GOAL

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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AN ACHIEVABLE GOAL

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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AN ACHIEVABLE GOAL

17


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


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.

soil.mep 30/04/01 12:01 Page 23


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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AN ACHIEVABLE GOAL

Gregorich, E.G., Greer, K.J., Anderson, D.W., and B.C. Liang (1998): Carbon distribution and

losses: Erosion and Deposition effects. Soil & Tillage Research 47, 291-302.

Johnston, A.E. and I. Steén (2000): Understanding Phosphorus and its Use in Agriculture.

European Fertilizer Manufacturers Association EFMA (in print).

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Environment. ISBN 0 85199 358 3.

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Bodenkunde, Landeskultur und Landschaftökologie, Band 17, 77-90, 1997. Felix-Henningsen, P.

und Wegener, H.-R. (Editors).

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and A. Vatn (Editors)

soil.mep 30/04/01 12:02 Page 27


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

28


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

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