Agriculture Reference
In-Depth Information
facilitates the effective distribution and management of new crop varieties. Making these
work, however, is very challenging.
To extend improved seeds in developing countries, researchers need to produce quality
seeds sustainably, which really requires a commercial farming environment that is lacking in
food insecure areas that rely primarily on subsistence agriculture. Even in these areas, however,
there is a significant community of agricultural workers, researchers and the institutions that
are aiming to promote income-generating prospects for traditionally subsistence crops. The
focus of these activities is to enhance the prospects of establishing a sustainable and effective
seed industry that will serve the needs of growers and lead to significant improvements in the
efficiency of production.
An example of the agricultural development projects is the work of the Consultative
Group on International Agricultural Research, that focusses mainly on cassava in East Africa.
The organization uses a value chain approach to improve the productivity and commercial
value of cassava. In practice, this means developing and promoting cassava-based products
(such as commercially sold chips, high quality cassava flour, starch and others), improving the
efficiency of marketing and markets for these products, and address the major pest and disease
constraints. The group simultaneously establishes virus-free, high yielding stocks of planting
material of newly released and farmer-preferred varieties, and works with small-scale cassava
entrepreneurs to set up seed production and distribution businesses. As farmers get improved
commercial opportunities for their cassava crops and processed products, so the potential for
them to access and purchase improved seeds (and other inputs) should increase. There is
much promise for major development along these lines in the next decade or so without
having to resort to crop modification using genetic engineering, other than the usual conven-
tional breeding that continues to deliver successful outcomes for increased productivity,
drought tolerance and pest/disease resistance.
Studies such as that by Hamukwala et al . (2010) have showed that in East Africa, yields
have been stagnant at about 0.5 tons per hectare for over 20 years. According to their study,
average seed replacement rate in Zambia was 13.7 years compared to the three-year rate rec-
ommended in the area. Seed replacement rate is the percentage of area sown out of total area
of crop planted in the season by using certified/quality seeds instead of farm saved seed. This
means that the last time farmers in Zambia purchased commercially produced, high yielding
hybrids was in the late 1990s. To drastically improve yields in areas with low productivity,
new varieties will need to be used, as well as appropriate levels of fertilizer, in particular
Fertilizer includes macro- and micronutrients required by plants to grow and produce
grain at the highest possible rates. Inorganic fertilizer typically provides the following nutri-
ents in varying proportions, depending on the soil type where the crop is grown:
• sixmacronutrients:nitrogen,phosphorus,potassium,calcium,magnesiumandsulfur;
• eightmicronutrients:boron,chlorine,copper,iron,manganese,molybdenum,zincand
Yields in the United States and the United Kingdom tend to be 40 to 60 percent attributable
to fertilizer, and according to Stewart et al . (2005), these percentages should be much higher
in the tropics given the relatively low organic content of tropical soils. Calibrated budgets for
nitrogen, phosphorus and potassium indicate that commercial fertilizer makes up the majority
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