Outlook for crop growing conditions in Southern Africa for 2003/2004
Seasonal cumulative satisfaction of maize water requirements is poorly correlated with early season rainfall. Scant early rains do not necessarily imply poor crop production for the 2003-04 season. Statistical interpretations of climate forecasts suggest that near-normal end-of-season maize crop water conditions are likely. Western Zimbabwe and Northern Namibia have below normal forecasts. Prospects for the season will come more clearly into focus by the end of January, once the quality of the December-January rains is known.
In non-El Niño years, October-November rainfall is poorly correlated with seasonal cumulative crop water satisfaction in the Southern Africa crop growing regions examined here.
A statistical downscaling of IRI climate forecasts suggests near-normal crop growing conditions for most crop growing areas.
Below normal forecasts for western Zimbabwe warrants concern.
The Climate Prediction Center's precipitation forecasts suggest near-normal rainfall in eastern southern Africa, and below-normal rainfall in western southern Africa. Deficient rainfall in northern Namibia could be a concern. Prospects for the season will be considerably clearer by the end of January 2004.
Much of Southern Africa is coming out of a series of poor seasons in which production was generally below normal. Apart from South Africa, most of the countries highlighted in this report had below-average maize production in the last few years. After several years of poor harvests, Zimbabwe is in a food security emergency, and particularly the southern provinces of Matebeleland North and South are highly food insecure. Relatively modest shocks associated with below-normal rainfall could produce troubling outcomes. Recent FEWS NET reports ' indicate that between 4.36 and 5.02 million will need food aid between January and March', while 'severe constraints on seeds and other inputs will limit agricultural production'. In Swaziland, IRIN reports suggest that by January 2004, WFP will be feeding approximately 245,000 people, about a quarter of the population. Swaziland is also coming out of several years of poor harvests. Namibia recently issued an appeal for international assistance for immediate food assistance for 643,000 people. Although crop production was poor in the previous two seasons, food insecurity in southern Mozambique may not be at critical levels, because of household reliance on sources other than crop production. South Africa is the biggest grain producer in the region, and normally produces a surplus permitting export to nearby countries. However, the poor rains so far may cause large reductions in area planted, potentially compromising crop production quite significantly.
Given this bleak picture of the current food security conditions, the outcome of this growing season is of paramount importance. This report examines the 2003/2004 crop water satisfaction outlook for eleven crop-growing regions in Southern Africa. Time-series of mean maize Water Requirement Satisfaction Index (WRSI) were extracted for each region, compared to historical rainfall values, and predicted for 2004 based on a statistical downscaling of forecast precipitation and wind fields from the International Research Institute for Climate Prediction (IRI). The results indicate that: i) early season rainfall bears little relationship to end-of-season WRSI, and ii) the December-January-February outlook appears close to normal. This outlook is broadly consistent with a range of probabilistic forecasts provided by the National Ocean and Atmospheric Administration (NOAA) Climate Prediction Center (CPC) and IRI, though their forecasts tend to be slightly more pessimistic. It should be noted that this study only adresses crop water availability, while many factors influence production.
Given the weak relationship between early rains and end-of-season maize WRSI, it appears possible, but not certain, that favorable December-January rainfall will produce healthy yields. Given fairly neutral sea surface temperature conditions, near-normal crop growing conditions in the southern SADC countries for the remainder of the season appear likely. However, the CPC has noted a warming trend in the Indian and Pacific oceans that could adversely affect Southern Africa precipitation in the remainder of the season. Prospects for the season will come more clearly into focus by the end of January. A follow-up report to this one will be issued at that time.
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