Early season drought in Zimbabwe & Mozambique, EARS-FAST issue Jan 4, 2013
Data and method Meteosat visual and thermal infrared images have been processed to relative evapotranspiration (RE) for the years 2004 to 2012. Relative evapotranspiration is a measure of plant available water and plant growth. It is the best possible agricultural drought indicator. RE data have been averaged for the months October to December 2012 so as to provide a measure of water availability in the starting phase of the growing season (figure A). The difference evapotranspiration (DE) relative to the previous 8 year is shown in figure B. The last figure (C) presents the agricultural drought situation at the very end of 2012.
Early season drought in Zimbabwe & Mozambique Figure A shows that the last three months of 2012 were relatively dry in Zimbabwe and Mozambique, implying a later start of the growing season. This is even more evident from figure B, which shows the difference of the current year relative to the previous 8 year. Water availability in this area is 10 to 20% below average. Relatively good conditions prevail along the coast of Mozambique and South Africa. During the last 10 days of December (see figure C) plant water availability has much improved, except for the south of Zimbabwe and just across the border in Mozambique, where drought persists.
Reduced crop yields expected The effect on crop yield will be significant. Crop growth is proportional to RE (Doorenbos and Kassam 1979, FAO Irrigation & Drainage Paper 33). Moreover a late start of the season is often associated with an early end. FAST crop yield forecasts at national, provincial and district level are generated from halfway the growing season and may be ordered through the contact below