FOOD SECURITY - Science for Agriculture and Rural Development in Low-income Countries - page 44

Maize production and yields in Sub-Saharan Africa

Maize production
Most of the maize produced in Sub-Saharan Africa originates from South Africa,
with, however, very strong variations, i.e., between 4 and 12 × 10 6 Mg between low-
and high-rainfall years. Production has almost doubled over the last 40 years, with
strong increases particularly in the 1970s and 1980s in Tanzania and to a lesser
extent in Kenya (with around the year 2000, values of 4 and 2.5 times, respectively,
those around 1960). In Mozambique and Ethiopia, maize production started to
increase towards the end of the 1980s, but has more than tripled over the period
1985-1995, which clearly is related to the end of (civil) wars. In Zimbabwe, maize
production is extremely variable, but clearly decreases over the last years.
Production in 2001-2004 is similar to or less than that in the beginning of the 1960s,
related to counter-productive government policies.

Maize yield

-1 in the beginning of
the 1960s to about 2500 kg ha -1 at present. Inter-annual yield variation is very large
due to the large rainfall variability, i.e., less than 1000 kg ha -1 in drought years to
over 3000 kg ha -1 in high-rainfall years. Yields in Zimbabwe in the 1960s were
about similar to those in South Africa, showed a slight increase in the following
years, but with an inter-annual variation between 700 and 2000 kg ha -1 , and then
clearly decreased after 1990 (to about 600 kg ha -1 ) due to policy failures and
political turmoil. In the 1960s, yields in Kenya were about 1250 kg ha -1 and about
900 kg ha -1 in the other African countries and have increased to about 1600 kg ha -1
in Kenya at present. Yields in Ethiopia had almost doubled to about 1700 kg ha -1 at
the beginning of the 1980s and remained (except in drought years) roughly at that
level. Mozambique showed about a 50% decrease in yield from the beginning of the
1980s to the beginning of the 1990s, associated with civil war. From halfway through
the 1990s, yields rapidly increased again, attaining a level of about 950 kg ha -1 ,
slightly higher than at the beginning of the 1960s (Figure 6).
The Sub-Saharan African agricultural production data clearly illustrate that
despite the gloomy picture that is often painted, technological progress has resulted
in substantial improvements in food production (cf. Breman and Debrah 2003).
However, in addition to the poor soils and the low and erratic rainfall patterns that
form major biophysical constraints to sustainable yield improvements, the socio-
economic environment is not conducive to intensification. Civil unrest, counter-
productive policies and the devastating effects of the HIV/AIDS epidemic, all
constrain adoption of improved yield-increasing technologies. Economic incentives
are all but absent, labour availability is insufficient and land tenure is highly uncertain
in many regions, and their effects are clearly illustrated in the yield dynamics in
Figure 6.
Yield increases, realized in the past have, in many instances, come at considerable
environmental costs (Van Keulen 2007; Verhagen et al. 2007). In the following
section we shed some light on some environmental impacts of increasing food supplies
in the past and present, and examine possibilities to reduce the environmental

Maize yields in South Africa have increased from 1300 kg ha