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Production
Estimates and Crop Assessment Division |
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Production
Estimates and Crop Assessment Division |
March 26, 2003
Tanzania had several weeks of below-normal rainfall in early March, resulting in short-term dryness that may adversely affect the 2003/04 cotton crop grown in Mwanza and Shinyanga regions, the two main cotton-growing regions in northwestern Tanzania. Satellite images, shown in Figure 1, reveal that current NDVI (or vegetation health) for Tanzania is below-normal, especially in the main northern cotton regions. Additional satellite images reveal that cumulative precipitation and surface wetness for March 2003 were below normal for most of the country.
Figure 1. Below-normal NDVI (vegetation health) for March 20 2003
USDA has not yet released 2003/04 cotton production forecasts, but the Tanzania Cotton Board in December forecasted the 2003/04 crop at 310,000 bales on 285,000 hectares, which would be a near-record yield. The current drought will prevent record yields this year and correspondingly will reduce 2003/04 production forecasts. Over 90 percent of Tanzania’s cotton crop is grown in the northwest, where unimodal rainfall typically allows planting to occur from late November to January (Figure 2), and harvesting begins in June. (Refer to unimodal and bimodal agricultural regions).
Figure 2. Average Start of Cotton Season in Tanzania
The local marketing year for Tanzanian cotton is from August/July; USDA's cotton production database was recently adjusted to correspond to the local marketing year. Before making this adjustment, USDA assumed Tanzania’s growing season and marketing years were the same, which is commonly done for most southern hemisphere countries. However, even though Tanzania is located in the southern hemisphere, the main cotton region is equatorial, with the majority of harvesting occurring after June 30th; only one month difference separates USDA’s marketing year (July/June) from the local marketing year (August/July). The graph below summarizes USDA’s cotton production database for the past ten years and it includes all recent USDA adjustments made to the marketing year (Figure 3).
Figure 3. Cotton Area and Production Estimates for Tanzania
March is also a very critical month for Tanzania
cereal crops because it straddles
the
long rain seasons in both the unimodal and bimodal rainfall regions. For example,
corn is at critical flowering stages from February to March for the southern unimodal
region (long musumi rains from November-May), and corn is typically
planted in late February and early March for the northern bimodal regions
(long masika rains from February to June). (Refer to
crop zones and crop calendar).
The southern corn belt in the unimodal region accounts for approximately 45 percent of total maize production, and another 40-45 percent of corn is produced from the long masika rains in the northeastern bimodal regions of the country. Masika crops are normally planted by March, and the current dry conditions in March have significantly delayed these planting. Unfortunately, delayed start of season in east Africa tends to lead to reduced growing period lengths, reduced seasonal rainfall amounts, and reduced yields. In summary, poor rainfall during early March may reduce yield potential for Tanzania's cereal and cotton crops grown in both unimodal and bimodal rainfall regions.
Cotton Production Regions
Unimodal and Bimodal Rainfall Regions
Crop Calendar
Crop Zones
Cropland in Tanzania
Administration Divisions
Tanzania
Cotton Board
World Bank
Report (December, 2002)
Tanzania: Ministry of
Agriculture
NOAA
Surface Wetness
NOAA Rainfall Anomalies for sub-Saharan Africa
Africover Landcover Data
