Report No 2 - 12 Juilet 1996
REDUCED RAINS IN BURKINA FASO IN JUNE WILL NECESSITATE SUBSTANTIAL REPLANTINGS. ELSEWHERE RAINS AND PLANTINGS ARE PROGRESSING NORTHWARDS
Precipitation progressed northwards in June over the Sahel region except in Burkina Faso where, following above normal rains in mid and late May in the south and the centre, precipitation decreased significantly in mid and late June over most parts of the country. Therefore, recently planted coarse grains are likely to fail in many areas and substantial replantings will be necessary. In Mali and Niger, rains progressed northwards in June allowing widespread plantings. In Chad, widespread rains covered the south and the centre. In Senegal, clouds covered the entire country in mid June, while widespread rains benefited plantings in the Gambia and Guinea Bissau. In Mauritania, plantings are underway following the arrival of the rains in June. Seasonably dry conditions still prevail in Cape Verde.
The last Meteosat satellite image for the first dekad of July indicates that precipitation improved significantly over Burkina Faso, southern Senegal, Guinea Bissau and southern and central Chad where rains appear to have been quite abundant. Elsewhere, cloud coverage is present and therefore rains are likely to have remained widespread over the main producing areas, except in northern Senegal and south-western Mauritania where the weather was mostly dry. Rains in Burkina Faso will permit a crop recovery following mostly dry conditions in June. Elsewhere, growing conditions are generally favourable.
Desert Locust activity has been reported in Mauritania, northern Mali and Niger. As vegetation dries out in northern Africa, adults that escape detection and control are expected to form small swarms which will move southwards into northern Mali and Niger and perhaps east towards Chad. Reports of locusts in north-eastern Niger suggest that this movement may already be underway. Only scattered showers have fallen so far in the northern areas of the Sahel and favourable breeding conditions are limited to just a few areas. However, conditions are expected to improve over larger areas extending from Mauritania to central Sudan once the seasonal rains commence.
In the coastal countries of Western Africa, the growing season is well underway. Plantings of millet and sorghum are underway or drawing to an end in most countries, while the first maize and rice crops are growing satisfactorily. Rains were abundant in May and decreased in June but remained widespread. Cumulative rainfall as of the end of June was close to normal in the area as a whole.
BURKINA FASO CAPE-VERDE CHAD GAMBIA GUINEA-BISSAU MALI MAURITANIA NIGER SENEGAL BENIN CAMEROON COTE DIVOIRE GHANA GUINEA LIBERIA NIGERIA SIERRA LEONE TOGO
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.