Land preparation and planting are progressing following the onset of the rains. Crops are emerging satisfactorily in Burkina Faso and southern Chad and Mali.
Grasshoppers are reported in Burkina Faso and eastern Guinea Bissau.
No Desert Locusts were reported recently in the region. Low numbers of
adults are expected to appear in the summer breeding areas of southern
Mauritania, and northern Mali and Niger. These will lay eggs with the onset
of the seasonal rains. However, the scale of breeding this summer is expected
to be very small. African Migratory Locusts hoppers resulting from residual
populations following infestations in late 1997 have been reported in Chad,
POSSIBLE IMPACT OF EL NINO IN THE SAHEL ?
In late 1997 and early 1998, the weather phenomenon called El Niño severely affected rainfall and crop growing conditions in several continents. El Niño ("the Christ Child") is the name given to the occasional warming of surface waters in the central and eastern equatorial Pacific Ocean. Sea-surface winds blow from east to west towards the equator and pile warm water in the ocean of the western tropical Pacific near Indonesia and Australia. As a result of this warm pool of water, the atmosphere is heated and conditions favourable for precipitation occur. Such a phenomenon, which is known to occur every 2 to 7 years, with varying degrees of intensity and duration, may affect agriculture and water resources either positively or negatively.
This year’s El Niño is regarded by various experts as one of the most severe this century with record Pacific ocean surface temperatures being observed. In Asia, El Niño-related droughts have affected cereal production in Indonesia, China, Korea D.P.R, the Philippines, Thailand as well as Papua New Guinea in the Pacific Rim. In Latin America, abnormal dry weather delayed plantings in Central America while substantial perturbations have been registered in Bolivia and Nordeste of Brasil. In Africa, alternating droughts and floods, whose relation with El Niño is not established, caused substantial losses of crops and livestock in most of eastern Africa and in several countries of central Africa. By contrast, in southern Africa, the fears of a severe drought similar to the El Niño of 1991-92 have not materialised.
As regards the impact of El Niño in western Africa, during the
past months, unusually high temperatures have been registered in most sahelian
countries, reaching 2 to 5 degrees above normal. Popular belief is that
this is a sign of a good growing season. Scientists who met on the subject
in early May in Abidjan confirmed this, indicating that probability was
greater for normal or above normal rainfall over the Sahel than for below
normal rainfall, notably in the north-west of the Sahel. Predictions from
NOAA (National Oceanic and Atmospheric Administration) – Africa desk -
indicate that probabilities are slightly higher for above normal rainfall
in central Sahel, while they are slightly higher for below normal rainfall
across western Sahel and parts of eastern Sahel. However, it is too early
to make definite conclusions and FAO/GIEWS will monitor closely developments
throughout the season.
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.