Global Information and Early Warning System
SAHEL Report no 6, 11 October 1995
A GOOD COARSE GRAINS HARVEST IS IN PROSPECT IN THE SAHEL
Precipitation remained well distributed over the main producing areas of the
Sahel in early and mid-September. The southwards movement of the rains has started
during the third dekad of September. Dry weather prevailed in late September
in northeastern Mauritania,
the extreme west, central and northern parts of Burkina-Faso
and central Chad, which received heavy rains. In
The Gambia, precipitation remained also
quite abundant. In
In these reports, reference will be made to four different eco-climatic zones based on the average annual precipitation and agricultural features, i.e. Sahelian zone, Sudano-Sahelian zone, Sudanian zone and Guinean zone. They appear on the map and are described below:
Sahelian zone: Where average annual precipitation ranges between 250 and 500 mm. This zone is at the limit of perennial vegetation. In parts where precipitation is less than 350 mm, only pastures and occasional short-cycle drought-resistant cereal crops are grown; all cropping in this zone is subject to high risk.
Sudano-Sahelian zone: Where average annual precipitation ranges from 500 to 900 mm. In those parts of this zone where precipitation is less than 700 mm, crops with a short growing cycle of 90 days are generally cultivated, predominantly sorghum and millet.
Sudanian zone: Where average annual precipitation ranges from 900 to 1 100 mm. In this zone, most cereal crops have a growing cycle of 120 days or more. Most root, cash crops and cereals, notably maize, are grown in this zone.
Guinean zone: Where average annual precipitation exceeds 1 100 mm. Guinea-Bissau and a small area of southern Burkina Faso belong to this zone, more suited to root crop cultivation.
Reference will also be made to the Intertropical Convergence Zone (ITCZ), also known by its trace on the earth's surface, called the Intertropical Front. The ITCZ is a quasi-permanent zone between two air masses separating the northern and southern hemisphere trade winds. The ITCZ moves north and south of the equator and usually reaches its most northerly position in August. Its position defines the northern limits of possible precipitation in the Sahel; rain-bearing clouds are generally situated 150-200 km south of the Intertropical Front.
In this report, FAO/ARTEMIS rainfall estimates, field data on rainfall, FAO agro-meteorological crop monitoring field reports and information provided by FAO Representatives and World Food Program offices up to 10 October have been utilized. The last satellite images up to 9 October have also been utilized for final updating.