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Why soils matters

- A european perspective

Stephane le Foll launches the programme

4 for 1000

(‘4 pour 1000’), which aims to increase the organic

content of the soil by 4gr per 1000gr of carbon stock

in the soil. If this programme is implemented with an

increase in the organic content of 4 per 1000 every

year, this could result in soils absorbing the totality of

global carbon dioxide emissions, representing 75%

of total man made GHG.

So, soil is an essential, vital asset in combating

climate change and reducing GHG emissions. But at

the moment we are losing this battle as a result of

the quality of the soil.

There is today a debate within the international

community as to how to re-launch agriculture, how

to increase the ability of agriculture to satisfy a

growing demand for agricultural products.

We can

summarize 2 approaches to these questions:

- The first approach is the classic, conventional

approach - sometimes still called ‘the green revolution’

approach - which insists on bringing more external

inputs: pesticides, synthetic nitrogen-based fertilizers-

based on the NPK formula (Nitrogen-Phosphorus

and Potassium), to re-inject into the soil the fertility

that it would otherwise be losing. This approach also

invests in mechanisation, large-scale irrigation and

use of improved varieties of plants - so-called high-

yielding varieties, often commercially bred seeds. This

commonly known approach is expanding in Africa after

having been developed in South America in the 1950’s

and in south Asia in the 1960’s and 70’s. It is the model

that has been promoted in Europe since the 1920’s.


Agroecology is the other approach.

It is a different

way of looking at the challenge of agriculture. A way of

looking at agriculture that recognizes the complexity of

nature, the natural interaction between plants, trees

and animals, and tries to replicate at farm-level the

natural interactions between these different elements.

Rather than simplifying nature, it recognises the

complexity of nature and adapts agricultural practices

to this complexity, to play with nature as an ally rather

than reducing nature to a chemical formula.

This implies a range of agronomic techniques:



the use of trees to reduce erosion, to

allow soil to better capture moisture from rainfall. For

example, in Africa there is currently a widespread use

of a particular type of acacia, called Acacia Faederbia,

which is a fertilising tree that re-injects nitrogen into the

soils, enabling farmers to plant trees around their fields

to reduce their dependency on chemical fertilisers.

And we see this developing well in countries such as

Zambia and in the Sahel: in Mali, Burkina Faso, Tchad,

Sudan, Niger. It is this method - agroforestry - which

is promoted by the Nobel Peace Laureate

Wangari Matthai

, or in Africa by the

World Agroforestry Center


UN Environmental Programme



Biological control:

using plants rather than pesticides

in order to protect cultures. E.g in Africa, beginning in


Hans Herren

developed the use of desmodium

intercropped with maize, in order to repel insects which

attack either maize or sorghum, and alongside the field

of maize intercropped with desmodium, you plant a

grass called


which attracts the pests and traps

them alongside the field. And this biological control is

again a way to play with nature, rather than trying to

simplify nature thanks to the use of chemicals.


Use of leguminous plants

, such as peas, beans, alfalfa

and clover, in order to fertilise the soil and reduce the

need to rely on chemical fertilisers

We are now at the end of the cycle where the

‘Green Revolution’ approach was seen as desirable

and as the only way forward.

This is for 4 reasons:

- ‘Green Revolution’ approaches lead to a significant

dependency of agricultural production on non-

renewable resources. Gas to produce nitrogen-based

fertilisers, oil for mechanisation, phosphorus which is

mined in different parts of the world and is not infinitely

available either. Even nitrogen - we remove nitrogen

from the atmosphere at a rate 4 times above what

should be allowed. We remove about 120 million tons of

nitrogen per year from the atmosphere, when it would

be sustainable to use no more that 35 million Tons.

Proceedings of the Conference