EARS FAST Crop Yield Forecast
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EARS FAST Crop Yield Forecast Maize - East Africa - 15 September 2008 Subject: Forecasted Maize Yield Region: East African countries Issuing date: 15 September 2008 INTRODUCTION The present document provides a preliminary forecast of crop yield expected at the end of the current growing season. Forecasts are provided from halfway the growing season (70 growing days). Although at that time the most critical stages of crop development have passed, the final outcome may still be subject to some change depending on how the second half of the season proceeds. Our forecasts are updated regularly with the most recent satellite data and we advise you to check our website (www.ears.nl) for the most recent bulletin. METHOD FAST is the acronym of Food Assessment by Satellite Technology , a Meteosat based crop yield forecasting system developed and operated by EARS in Delft, the Netherlands. The assessment of crop growth conditions and the crop yield forecasts are based on visible and thermal infrared hourly data. These data are processed in 3 steps: (1) Hourly Meteosat data are processed to daily average values of surface temperature, air temperature, global radiation, net radiation, potential and actual evapotranspiration. (2) Radiation and evapotranspiration data enter into a crop growth model, which simulates crop yield on a daily basis. (3) Distributed crop yield results are integrated for crop growing areas, countries and provinces. Urban areas, forest, water and barren land are excluded. CROP The crop calendar in Figure 1 shows the vegetative period (green), the Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec mid-season period (grey) and the BURUNDI sec harvesting period (yellow) for the CENTR AFR REP CHAD countries in the region. The yield DR CONGO response of the plant to DJIBOUTI evapotranspiration deficits during ERITREA the growing season is quantified by ETHIOPIE main KENYA long rains the yield response factor K y, based RWANDA sec on the relationship described by SOMALIA main Doorenbos & Kassam (1986): SUDAN (SOUTH) TANZANIA (1-RY) = K y (1-RE) UGANDA main RY is the relative yield and RE the Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec relative evapotranspiration. Drought sensitivity © FAO 1997 of a crop changes during the growing season. Figure 1: Maize Crop Calendar For maize, K y is 0.4 during establishment, increases to 1.5 during the vegetative period, is kept constant at 1.5 during flowering and yield formation and decreases to 0.5 during ripening. EARS – Satellite Data for Water and Food 1 EARS FAST Crop Yield Forecast Maize - East Africa - 15 September 2008 SUMMARY Kenya and Eritrea face reduced yields of respectively -7% and -4% relative to the 5 yr average. In Sudan water availability has increased past half month and better growing conditions are seen in Darfur and Kordofan . In the regions south of Lake Victoria, yield decreases (-15%) are expected in the east of Burundi and the north of Tanzania . Slightly above average yields are predicted for Rwanda and south Uganda . Low yields in the north of Tanzania are compensated by high yields in the centre of the country, and therefore at national level maize outputs are expected to be closely above average (+2%). In Rwanda crop water availability has improved the past half month and a moderate increase of 4% is foreseen. In the maize growing area's of Somalia crop water availability during the growing season has decreased the last half month and deviation from the previous 5 years is around -1%, while the difference with 2007 remains positive (+4%). Yields expectations are at average in Ethiopia (+0.1%) but lower than the previous year (-7%) and there are considerable differences between the west and the east of the country. DETAILS In Kenya drastically reduced maize outputs (-15%) and a decrease of yield in large parts of the agricultural areas in the country is anticipated due to drought. Especially in the Rift Valley province low yields are seen in Laikipia, Kajiado and Narok In Uganda , water availability is good and relatively normal in most parts of the country. In Tanzania , water availability and crop prospects are better than normal in the central part of the country while in the northern part yield decreases are expected. In Tanga, Rukwa, north Mbeya, south Tabora and south Singida above average yields (+5%) are seen. In the north, large parts of provinces like Shinyanga, Arusha, Mara, Mwanza, Kigoma suffer from drought and below average productions are foreseen. In western regions of Ethiopia , the water availability for the crops was very good and average high yields of 5% to 11% are expected in regions like Benishangul Gumuz, Gambela, western part of Oromia and Amhara and the northern part of SNNP. By contrast, other regions in the east of Ethiopia like Afar, Somali and east Oromia suffer from water shortages and show considerable local differences, with regional yield decreases of -18% in Afar and -3% in Somali. In Central Sudan water availability has improved and yields are now expected to be higher than the 5 years average in West Darfur, North Darfur and Kordofan. In North Bahr el Ghazar and Warab, harvests could be damaged by the floodings, so reported difference yields could be lower than is reported here (+5% and +0.3%). In Somalia , the growing areas in general show relatively normal growing conditions with positive deviations from the 5-years average of about 2% in Shabelle and slightly below normal conditions in Hiran (-2%) and Bay (-0.2%). In general, the yield prospects in Somalia are better than the previous year except in Woqooyi. In non-cropland areas of northern parts of Somalia and provinces like Nugaal and Saraag water availability for the vegetation has improved a lot the past dekads and is now above the 5 yrs average. MAPS The maps on next page show the Meteosat derived difference yield (DY) relative to the 5 yr average (figure 2a) and to the previous year (figure 2b). The actual growing areas, as defined by FAO, are shown in figure 3a and b. EARS – Satellite Data for Water and Food 2 EARS FAST Crop Yield Forecast Maize - East Africa - 15 September 2008 DY (%) (a) (b) Figure 2a: Crop difference yield relative to the Figures 2b: Crop difference yield relative to 5 yr average (in %) 2007 (in %) Figure 3a: Main growing areas (FAO) Figure 3b: All growing areas (FAO) EARS – Satellite Data for Water and Food 3 EARS FAST Crop Yield Forecast Maize - East Africa - 15 September 2008 TABLES The following tabulated data are provided on next pages: • Table 1 : Difference Yield forecasts at country level • Table 2 : Difference Yield forecasts at provincial level The difference yields for each province/country have been determined by spatial integration of pixel values within the growing areas of the crop. Data are provided for two growing areas: • All growing areas (figure 3b) • Main growing areas (figure 3a) The Difference Yield (DY) presents the forecasted 2008 yield in terms of % deviation from a reference yield. In the tables difference yields relative to two references are presented: • DY 08/07 : Forecasted difference yield relative to the yield in 2007 • DY 08/avg : Forecasted difference yield relative to the average yield of the years 2003-2007 REFERENCE Doorenbos, J., Kassam, A. H. (1986) . Yield response to water. FAO irrigation and drainage paper 33. Food and Agricultural Organization of the United Nations, Rome. ADMINISTRATIVE BOUNDARIES National, regional or provincial averages are calculated based on the administrative boundary layers from the Global Administrative Unit Layers (GAUL ) system. CONTACT For further information please contact: EARS Earth Environment Monitoring BV Kanaalweg 1, 2628 EB DELFT, the Netherlands Telephone: +31-15-2562404, Fax: +31-15-2623857 Email: [email protected] Website: www.ears.nl EARS – Satellite Data for Water and Food 4 EARS FAST Crop Yield Forecast Maize - East Africa - 15 September 2008 TABLE 1: MAIZE YIELD FORECASTS AT NATIONAL LEVEL Difference Yield (%) EAST AFRICA All Growing Areas Main Growing Areas 08/5yrs 08/07 08/5yrs 08/07 BURUNDI -2.3 -6.3 -3.2 -7.2 ERITREA -4.3 -24.0 -4.1 -24.0 ETHIOPIA 0.1 -6.5 0.9 -5.3 KENYA -7.2 -11.0 -7.4 -11.0 RWANDA 3.5 -1.3 5.8 0.6 SOMALIA -0.9 4.3 -0.9 0.4 SUDAN 3.6 -2.6 2.3 -2.1 TANZANIA 1.5 -1.7 4.4 3.2 UGANDA 1.3 -1.6 1.3 -1.6 EARS – Satellite Data for Water and Food 5 EARS FAST Crop Yield Forecast Maize - East Africa - 15 September 2008 TABLE 2: MAIZE YIELD FORECASTS AT REGIONAL OR PROVINCIAL LEVEL Difference Yield (%) All growing Main growing BURUNDI areas areas 08/5yrs 08/07 08/5yrs 08/07 BURURI 0.8 -2.9 - - GITEGA -5.0 -9.9 - - Difference Yield (%) All growing Main growing ERITREA areas areas 08/5yrs 08/07 08/5yrs 08/07 ANSEBA -3.8 -24.0 -3.3 -24.0 ASMAT -2.9 -25.0 -2.9 -25.0 HABERO 0.1 -22.0 0.0 -23.0 HAGAZ -6.1 -28.0 - - HALHAL -4.6 -23.0 -4.6 -23.0 SEMENAWI K. BAHRI -5.6 -25.0 -5.8 -25.0 NAKFA -3.1 -26.0 -3.1 -26.0 Difference Yield (%) All growing Main growing ETHIOPIA areas areas 08/5yrs 08/07 08/5yrs 08/07 AFAR -18.0 -18.0 -18.0 -18.0 AFAR ZONE 2 -12.0 -9.8 - - AFAR ZONE 3 -15.0 -16.0 -15.0 -16.0 AFAR ZONE 4 -24.0 -24.0 -24.0 -24.0 AFAR ZONE 5 -12.0 -16.0 -12.0 -16.0 AMHARA -2.3 -9.0 -5.9 -10.0 AWI 4.5 -4.5 2.2 -5.2 EAST GOJAM -1.1 -8.6 - - NORTH GONDER -0.7 -10.0 -2.0 -10.0 NORTH SHEWA (K3) -8.1 -12.0 -7.2 -11.0 NORTH WOLLO -7.5 -11.0 -10.0 -15.0 OROMIA ZONE -11.0 -12.0 -11.0 -12.0 SOUTH GONDER 2.4 -1.1 - - SOUTH WOLLO -7.3 -11.0 -10.0 -11.0 WAG HEMIRA -8.9 -18.0 - - WEST GOJAM 7.9 -2.3 6.0 -4.2 BENISHANGUL G.