Sustainable Agriculture

DefinitionA sustainable agricultural system

involves the modification of agricultural techniques in both existing industrialized and traditional agricultural systems in order to provide for the needs of current and future generations while conserving natural resources.

Requirements• Soils conservation must be reached. In other

words the soils cannot be degraded by erosion, Stalinization, water logging or loss of soil fertility.

• Water resources must be managed so that they are preserved yet still meet crop needs.

• The system must be economically viable.• The biological and ecological integrity of the

system must be preserved.

Characteristics• Sustainable farming, not only minimizes

the influence of farming on the environment but it also gives farmers more control over their livelihood.

• Application of sustainable agriculture practices results systems that are less prone to weather and changes in the marketplace.

Characteristics• It also cuts costs of running a farm by

requiring lower applications of inorganic fertilizers and pesticides.

• Yields from sustainable farms are generally lower than those of conventional systems.

• However, profits in the long-run can be higher because lower input costs and reduced environmental damage.

Case : Machakos District, KenyaMonth J F M A M J J A S O N DTemperature 27 27 28 27 25 25 24 24 25 26 26 27

Rainfall 38 64 125 211 158 46 15 23 31 53 109 56

Mukethe MbithiThe Machakos District where I live is prone to regular periods of drought. It is also one of the most densely populated parts of Kenya.

You would expect that it would be one of those place in Africa, which you often see on TV, where nothing grow and people go hungry.

In facts the opposite is true. We grow plenty of food and everybody is well fed.

Changes in Machakos, 1932-89

1932 1989Population 240,000 1,393,000

Population density (people per km2) in wet areas in dry areas

80

50

400 15

0

Population growth (% per year)

2.7 3.1

Livestock population units (1 unit=1 cow or 5 goats)

214,000 333,870

Soil Erosion• Until 1970 the Machakos district, like many other drought-affected parts o

f Africa, struggled with the problem of soil erosion. • As the population increased, more land was cleared for cultivation. Much

of this land was on steep hillsides where the rate of soil erosion was high. • Even worse, the increase in cultivation meant that less land was available

for grazing.• Livestock were squeezed on to smaller areas of land that became overgr

azed and, therefore, prone to erosion.

Soil and Water Conservtion

• The Kenyan Government set up the National Soil and Water Conservation Project (NSWCP) with support from the Swedish International Development Agency. Machakos was chosen as a pilot district and a soil and water conservation project was launched there in 1979.

Terraces created on hillside by building earth embankment

Maize grown to provide STAPLE food for people, and stalks for cattle

Banana trees grown in trenches where water collects

Animals manure on soil conserves moisture and adds nutrient

Grass plated on embankments to bind soil and feed cattle

Trees draw up water through their roots and help to keep the topsoil moist

Rainfall stays where it falls and soil is kept in the fields

Changes in agricultural output 1930-87

0

20

40

60

80

100

120

1930 1961 1977 1987

Out

put/k

m2(t

onne

s)

Food crops

Cash crops

Garden Plants

Livestock

Mukethe MbithiWith a better understanding of nature it is possible to do good rather harm.

We don’t need outside experts to come and solve our problems.

Often, it is the old methods that work best. We need to educate out children to produce a new generation of farmers using these methods. That will help to reserve years of environmental deterioration

Mulching

• Bare ground between plants is covered with a layer of organic matter, such as straw, grass or leaves.

• Mulching helps to retain soil moisture. reduces weeds and improves the soil structure.

Contour barriers

• Almost any material can be used to build barriers along contours, for example stones. grass or earth.

• Soil collects behind the barriers to form natural terraces. Trenches in front of the barriers help to catch water

Agroforestry

• Planting crops among trees helps to protect the soil from erosion. particularly after the crops are harvested.

• Tree roots also help to bind the soil, and the trees can provide fruit, fodder and firewood

Rock dams

• Land where gullies have begun to form can be restored by building permeable rock dams.

• These slow down the flow of water and prevent further soil loss.

Terraces • Terraces are built on

steep slopes to create flat surfaces on which to grow crops.

• They remove the sloping land and so reduce soil erosion and surface water run-off.

• They require skill and hard work to build.

Intercropping • A variety of crops,

mixed together in alternate rows or sown at different times, help to protect the soil from rain.

• The aim is to cover the whole area throughout the year.

Contour Ploughing • Land should never be

ploughed up and down a slope since this encourages erosion.

• Instead it should be ploughed along the contour lines, the plough lines then forming a natural barrier to water barrier to water flowing down the slope.

Land reform • Farmers who do not have

secure ownership of the land they farm are less likely to adopt soil conservation methods since these are often long term projects involving a lot of work.

• Land should be owned by the people who farm it as they are more likely to look after it.

Crop Rotation

When grass is ploughed back into the soil it increases the organic matter and helps to maintain soil structure. Other crop can help to

build up fertility. Bacteria within plants like clover and legumes, such as beans, are able to use nitrogen from the air to increase soil fertility

Animals grazing on the fields fertlise the soil naturally with their manure. This also adds organic matter.

Cereal crops, such as rice or wheat, take up large amount of nutrient from soil

UK’s Farmers are in Crisis• Agricultural production doubled from 1850 to 1998• No. of farmer : 1,500,000 (1950)• No. of farmer : 600,000 (1990)• Farm incomes fall by 60% in 5 years• Cuts in subsidies as over-production in the European Union is

tackled• Cheap imports from North America because protective tariffs

have been outlawed by the WTO• Falling meat consumption due to health• Cheap imports of pig meat from eastern Europe with less rules

Future of the UK’s Farmers• Intensive farming adds to the problem of over-production, and can d

amage the environment• ESA (Environmental Sensitive Area)• Niche marketing and direct marketing• Organic farming

– Environmental reasons– Economic reasons (higher price, lower cost in chemicals but increased labour

cost)

• Precision Farming– Farmers knows yields of each field (Yield map)– Put careful measures amount of fertilisers parts of field where it is most need

ed– Farmers knows where pests are so sprays areas where it is needed