SAHEL WEATHER AND CROP SITUATION 1997

Global Information and Early Warning System on food and agriculture

Report N^o3 - 8 August 1997

DRY WEATHER CONDITIONS ADVERSELY AFFECTED CROPS IN THE WESTERN PART OF THE SAHEL

SUMMARY
SITUATION BY COUNTRY
SITUATION MAP AS OF 8 AUGUST 1997
SOURCES OF INFORMATION
SOME DEFINITIONS

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SUMMARY

Following an early start of the rainy season in May/June in the western part of the Sahel, growing conditions have significantly deteriorated in July, notably during the second dekad of the month which registered only very limited rains or dry weather over most parts of Senegal, The Gambia and Mauritania. Precipitation also decreased in Guinea Bissau. By contrast, weather conditions have been much more favourable in the eastern part of the Sahel with well above normal rains in Chad, notably in its sahelian zone. In between, in the central part of the region, precipitation remained generally normal and widespread. In Mali, rains were widespread and quite regular, more abundant during the second half of the month. Similarly, precipitation increased significantly over Burkina Faso in mid and late July after reduced rains in early July. In Niger, rainfall remained generally widespread during July. In Cape Verde, rains have started over the main islands. The last Meteosat satellite image for the first days of August is showing a cloud coverage over southern Senegal, most parts of Mali, Burkina Faso, western and central Niger and Chad. Rains should have been quite abundant in Guinea Bissau and Chad. By contrast, weather remained mostly dry over northern Senegal, Mauritania and eastern Niger.

Plantings are finished in most countries but substantial replantings are necessary in Senegal, The Gambia and Mauritania. Reduced rains in July in the west of the Sahel have severely affected crop development and will diminish yield potential. Crops are generally growing satisfactorily in the centre and the east of the Sahel

Grasshoppers are reported in Burkina Faso, Chad, Niger and Senegal. Low numbers of solitary Desert Locust adults are present in southern Mauritania, northern Mali and western Niger where conditions are favourable for laying.

SITUATION BY COUNTRY

BURKINA FASO CAPE-VERDE CHAD GAMBIA GUINEA-BISSAU MALI MAURITANIA NIGER SENEGAL

SOME DEFINITIONS

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 are shown in the map and 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, mostly 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 cereals, notably maize, root and cash crops 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 July. 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.