Agriculture Reference
In-Depth Information
Table 1
Nitrogen balance of traditional maize farming in Northern Ghana
Nitrogen input (kg ha
-1
y
-1
)
Nitrogen output
14.4 kg N kg ha
-1
y
-1
Harmatan dust
5
1000 kg maize
Leguminous weeds
10
Manure
3
Nitrogen
efficiency =
(N output / N input)
×
100%
Erosion
2
Total
20
are the main inputs, yield levels will be around 500 kg ha
-1
. This means that whenever a farmer
uses inputs, yield level will increase tremendously. The most important question is: by which
extension method can we convince farmers to use locally available inputs like animal manure,
compost and green manures?
Extension is technically oriented
Existing agricultural policy and extension techniques are not successful in increasing soil fertil-
ity. The recommendations of Lynn (1937) to improve soil fertility and food security in 1937
(Box 1) are the same as the focus of Ministry of Food and Agriculture in 2005 (GV2020 2005).
The recommendations of Lynn (1937) and the Ministry of Food and Agriculture in 2005
(GV2020 2005) have never been promoted in a successful way. The main reason for this is that
the focus of extension was too oriented on the use of chemical fertilisers, pesticides and hybrid
varieties. Green revolution techniques in Ghana did not result in increasing soil fertility levels
and thus, yields. Besides that, chemical fertilisers can never be the solution since the prices of
fertilisers and pesticides over the last 15 years have been on such a level that farmers cannot
afford them. Farmers also observe the negative impact of chemical fertilisers on soil structure
and soil life (Box 2).
The 'training and visit' method of extension that accompanied the green revolution is, as
such, not a bad system of extension, partly because there is room to include social and cultural
issues. But whenever this system uses only a technical approach, promoting green revolution
farming without considering the ecological, social and cultural context of rural families, the
developmental effect is very limited. Or even worse, it makes farmers dependent on the fertiliser
Box 1 Recommendations by C.W. Lynn (1937)
Mr Lynn was a British agricultural superintendent studying 'indigenous agriculture'. In his
publication
Agriculture
in
North
Mamprusi
he mentioned the following suggestions to
improve farming systems:
• growth of a greater diversity of crops
• the introduction of crop rotation
• using cow manure to fertilise the soil
• cultivation of green manures
• use crop residues as litter instead of burning them
• plant crops in ridges made on the contour
• grow more rice in waterlogged areas
• improve varieties of seeds
Yield levels of maize, sorghum, millet and rice at that time were about 600 kg ha
-1
.
