|
|
|
|
|
|
April 4, 2002
Northwest Africa: Timely Rains Boost Wheat Potential in Morocco, but Precipitation Bypasses Most of Tunisia and Central/East Algeria
Summary:
Most of Northwest Africa has seen badly-needed precipitation return to the area since early March, with rainfall continuing into the beginning of April. Coming on the heels of a damagingly dry January and February, this widespread rain has fallen on the winter grain (wheat and barley) crop in Morocco and western Algeria as it enters the moisture-intense heading (reproductive) stage. With the increased soil moisture, some yield recovery can be expected. Rainfall coverage was not as complete in eastern Algeria and Tunisia. While the rain that has occurred has helped to ease the long-term dryness, rainfall has just not been as abundant in the east.
Despite beneficial rainfall over many parts of the region, soil moisture reserves remain well below average everywhere, and significantly more rainfall is needed to begin recharging soils after the long-term drought.
March Rainfall Patterns
The trend in March was for more rain in the west over Morocco and Western Algeria, and less to the east in Tunisia and Eastern Algeria. In Morocco, beneficial rainfall penetrated far inland and south (several times) reaching towards the more marginal growing lands around Marrakech where the more hardy crop, barley, is often grown instead of wheat. Morocco received the most precipitation, with the growing region averaging over 50 mm during the first 25 days. Rainfall subsided from west to east, leaving Tunisia with the lowest totals of the three countries, at an average of 28 millimeters by March 27th before more showers arrived.
Morocco March Precipitation Western Algeria March Precipitation
Central Algeria March Precipitation Weather stations in the central region are concentrated along the coast, so total accumulation only applies for the coastal production areas and does not extended inland, where precipitation quickly falls off.
Eastern Algeria March Precipitation Tunisia March Precipitation
Seasonal Precipitation Totals in the Agricultural Regions of Northwest Africa
All areas of Northwest Africa are below last year's rainfall level, which was below normal, but Morocco is faring better than Algeria and Tunisia. Morocco's cumulative growing season (since November) rainfall has been gradually approaching last year's level, thanks in large part to abundant March precipitation. Moroccan soil moisture has been playing catch-up since planting rains arrived quite late in the season (December). January and February were also very dry. In Algeria, western areas stand out as the best of the three coastal growing regions. While substantially better than Central and Eastern Algeria, the west is still well below average. Tunisia is also an area of concern, with rainfall remaining below average ever since the beginning of January. While rain has increased since March, Tunisia is only about 60 percent of normal.
Morocco Seasonal Precipitation Western Algeria Seasonal Precipitation
Central Algeria Seasonal Precipitation Weather stations in the central region are concentrated along the coast, so total accumulation only applies for the coastal production areas and does not extended inland, where precipitation quickly falls off.
Eastern Algeria Seasonal
Precipitation
Tunisia Seasonal Precipitation
Vegetation Comparisons
Using satellite imagery analysis, vegetation "greenness" can be calculated, representing plant biomass or plant vigor (sensor used is the NOAA AVHRR-16 platform). In croplands, the higher the NDVI (Normalized Vegetation Index), the better the condition (the greener or healthier) of the crop. With little January and February rainfall, early vegetation greenness graphs are even lower than last year's below-average crop. These values represent crop vegetation that is less vigorous and likely to produce lower yields than last year. However, late-planted crops in Morocco are developing at a later date than they would have under normal rainfall, so Morocco's vegetation graphs cannot be directly year-to-year compared. Additionally, March rainfall will surely boost the drought stressed crops' health, and these NDVI's are only current through February. Furthermore, there is a delay in a plant's response to new moisture. For example, rain received in late March would probably not stimulate recordable biomass growth until April.
Satellite Data/Vegetation
Vigor
Comparison between March 31, 2002 and March 15, 2002 Darker red color in the more recent image appears in Morocco indicating a "greening up" of the vegetation.
Comparison between March 31, 2002 and March 31, 2001 Morocco appears much more red in the 2002 image than in the 2001 image, indicating a rebound for the vegetation. On the other hand, Tunisia had much more "redness" or plant development at this time in the 2001 image: Note how the dark red band (representing vegetation) is much wider and goes much farther south last year than it does this year.
Northwest Africa Vegetation Index Map, March 15, 2002
Northwest Africa Vegetation Index Graphs (NDVI)
Western Algeria Central Algeria Eastern Algeria
Northwest Africa Precipitation
March Precipitation Map for Northwest Africa (3/21-3/30)
March Precipitation Map for Northwest Africa (3/11-3/20)
March Precipitation Map for Northwest Africa (3/1-3/10)
Soil Moisture
Soil Moisture Conditions Maps for Northwest Africa
Cereal Production
Cereal Production per Individual Country:
Official USDA Production Reports
Weather Conditions:
Current Weather in Northwest Africa
For more information, please contact Bryan Purcell with the Production Estimates and Crop Assessment Division on (202) 690-0138. email: purcellb@fas.usda.gov
