Monitoring Agricultural Drought in Southern Africa - Monitoring and Predicting Agricultural Drought: A Global Study - page 273

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Ea rly Warning System
There are a couple of regional centers in southern Africa that focus on
meteorological, hydrological, and food security interests related to various
aspects of early warning and preparedness. These centers include the SADC
Drought Monitoring Center ( www.dmc.co.zw; chapter 32), and the SADC
Regional Early Warning Unit for Food Security and the Regional Remote
Sensing Unit (RRSU; www.sadc.fanr.org.zw). Significant progress has been
made in developing an early warning system for tropical cyclones in south-
ern Africa, but no agricultural drought early warning is widely operational
in southern Africa for the benefit of both producers and policy makers.
State drought declarations are largely dependent on field-crop failure re-
ports.

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D rought Preparedness and Mitigation Strategies
Maize is the staple food crop for much of southern Africa and is largely
produced under rain-fed conditions. Maize requires 500-800 mm of well-
distributed rainfall during the growing period. Because of its shallow root-
ing system that cannot draw water from soil depths greater than 80 cm,
maize is highly sensitive to water stress. Drought stress and poor soil fertil-
ity are the two most important physical factors limiting rain-fed crop pro-
duction in southern Africa (Heisey and Edmeades, 1999). Drought stress
affects maize production at three critical stages of plant growth: during es-
tablishment, at flowering, and during middle to late grain filling. A farmer
confronted with an early-season drought has several management options.
The options include replanting, planting a shorter maturing cultivar, or
planting a different crop that matures more rapidly or is more drought
tolerant than the original crop.
A mid-season drought is more devastating than drought at the begin-
ning or end of the season. A crop such as maize is more susceptible to
drought stress during the mid-season when the plant flowers. At this stage,
the farmer has no management options to respond to drought stress un-
less irrigation is available. To minimize water stress-related fluctuations in
crop yield, a number of drought mitigation strategies have evolved across
southern Africa. The most common strategies include the promotion of
sustainable agricultural practices such as growing drought-tolerant crops
or varieties, minimum tillage systems, water conservation, building dams
for small irrigation projects, building sufficient grain reserves, and having
crop mixes that minimize impact of drought on food availability.
Through financial support from the United Nations Development Pro-
gramme, the Belgian government, NOAA, and the World Bank, a regional
Drought Monitoring Center was set up in Harare, Zimbabwe for the pur-
pose of providing a regionally coordinated drought early warning system
in 1990. The center post-processes global climatic data sets and seasonal
climate prediction products received from international climate prediction

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