Huambo, Bié, Cuanza Sul and Benguela)
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Agrometeorological Bulletin No. 2 Period October 2019 – May 2020 [English version] Agricultural Monitoring in Central Angola (Huambo, Bié, Cuanza Sul and Benguela) Highlights ● Weather conditions for the agricultural season have been generally normal to good. ● Overall water availability was good thanks to abundant rainfall between October 2019 and January 2020. ● Harvest of cereals is completed and production prospects for the region are favorable. ● Good rangeland biomass conditions are expected to support livestock conditions. Overview The four provinces of Huambo, Bié, Cuanza Sul and Benguela, located in the central part of the country, experienced a generally good agricultural season in 2019/2020 thanks to beneficial weather conditions. The abundant rains in the first part of the season (October to December 2019) replenished soil water storage preparing for the low rains in the second part of the season (January to May 2020). The positive early season rainfall also supported crop establishment, mainly maize, but also cassava in Cuanza Sul, dry beans in Benguela and Huambo, and potatoes in Huambo and Bié. The seasonal rainfall totals were close to average at the end of May 2020 for Huambo and Cuanza Sul, above-average for Benguela, and slightly below-average for Bié. Harvest of cereal crops is completed in the country. Weather conditions during the season as well as satellite images of vegetation status suggest that national production prospects are favorable (normal to good) for both crops and rangeland across the four provinces. Table of Content Highlights 1 Overview 1 Characterization of the Huambo, Bié, Cuanza Sul and Benguela Provinces 2 Analysis of ASAP Warnings 5 Rainfall Data and Meteo-Based Indicators 8 Vegetation Conditions since the Start of the Agricultural Season 14 High Resolution Satellite Imagery 16 Technical and Organizational Notes 18 Characterization of the Huambo, Bié, Cuanza Sul and Benguela Provinces The four provinces assessed in this bulletin are located in the central part of the country, as shown in Figure 1. Figure 1. Map of Angola with Huambo, Bié, Cuanza Sul and Benguela provinces highlighted in yellow. Croplands are more dominant in Huambo and Bié provinces (with 17.2% and 9.3% of the total area of the province respectively) in comparison with Cuanza Sul and Benguela (6.2% and 5.4% of the total area of the province). Cropland extent in Huambo and Bié is estimated at about 5,700 km2 and 6,700 km2 respectively (source: EC-JRC ASAP Warning Explorer). Rangelands are located mainly along the coastal and southern part of Benguela and along the coastal part of Cuanza Sul (Figure 2). In terms of extent, rangeland 2 area in Benguela and Cuanza Sul is estimated at about 8,500 km2 (21.6% of the total area of the province) and 2,450 km2 (4.4% of the total area of the province) respectively. Figure 2. Crop (top) and rangeland (bottom) maps for Angola (source: EC-JRC ASAP Warning Explorer). Angola has a main cereal cropping season, spanning from October/November to April/May that applies also to the central provinces. The planting, growing and harvesting dates can be seen in Figure 3. Figures 4 and 5 are based on data from the Ministry of Agriculture (accessed through CountryStat) and show the average cereal production (maize, millet, sorghum, and rice crops) of the period 2001-2014 for all provinces of Angola. The four provinces are all important in terms of cereal production. Huambo has the largest production of cereals, whereas Benguela has the smallest of the four provinces. Regarding single crop production (Figure 5), Huambo is the first province for maize with nearly 30% of the national production and the second for potato with 20% of the national production while Bié produces close to 30% of the national rice production. Bié is also important for potatoes, dry beans and maize with 15 to 20% of the national output for each crop. 3 Figure 3. Crop calendar presenting the starting dates for sowing, growing and harvest for major crops in Angola (source: FAO/GIEWS). Figure 4. Average production for cereals for all provinces in Angola (source of data: GEPE/MINAGRI accessed through CountryStat). 4 Figure 5. Contribution to the national production for various crops for Huambo, Bié, Cuanza Sul and Benguela. (Average data for 2001-2014, source of data: GEPE/MINAGRI accessed through CountryStat). Analysis of ASAP Warnings In Figure 6, 7, 8 and 9, the ASAP warnings for crops in Huambo, Bié, Benguela and Cuanza Sul are depicted. The matrices show the warning history for the years 2003-2020 (up to end of May 2020). INFO BOX 1 - ASAP WARNINGS The ASAP warnings indicate the crop areas experiencing adverse conditions that might lead to below- average production at the end of the cropping season or rangeland areas that might not support usual grazing regimes. Warning of level 1 refers to rainfall deficits that may evolve into poor vegetation growth, warning of level 2 points to poor vegetation growth, whereas warning of level 3 indicates a combination of the two. Finally, warning of level 4 suggests a failed season. The four provinces are less vulnerable to drought than the more arid regions in Southern Angola, but several years with warnings extending over one month or longer are visible in the historical time series. A particularly poor season that led to crop failure was experienced in 2012 in Benguela and Cuanza Sul. For the October 2019-May 2020 agricultural season, the four provinces had no warnings for most of the season. It can be concluded that the crops progressed well thanks to favorable weather conditions and there was no negative impact on vegetation growth. Only between end of March and end of April for Cuanza Sul, and from end of February to mid-April for Bié, warnings level 1 were experienced, pointing to rainfall deficits that however were not sufficient to result in strong below average biomass; so their potential impact on crop yield will have to be assessed in the field. The warnings level 2 in Huambo at the very beginning of the season are probably due to a delay of the start of the season that had no effects on the final vegetation growth. 5 Figure 6. Time series of ASAP warnings for croplands in Huambo (source: EC-JRC ASAP Warning Explorer). Figure 7. Time series of ASAP warnings for croplands in Bié (source: EC-JRC ASAP Warning Explorer). 6 Figure 8. Time series of ASAP warnings for croplands in Benguela (source: EC-JRC ASAP Warning Explorer). Figure 9. Time series of ASAP warnings for croplands in Cuanza Sul (source: EC-JRC ASAP Warning Explorer). 7 Rainfall Data and Meteo-Based Indicators Rainfall is a key indicator to monitor rainfed agriculture conditions, as it is one of the main limiting factors for plant growth in these provinces. In this section we present maps and graphs of a set of rainfall-derived indicators (based on rainfall estimates derived from a combination of satellite and station data) to assess the potential effects of rainfall on agriculture in the four provinces during the last agricultural season (October 2019 - May 2020). Figure 10 illustrates the spatial distribution of water availability to plants and rangeland during the growing season based on the ASAP Water Satisfaction Index (WSI) at the end of April. Blue areas represent positive anomalies (i.e. the water availability in the current year is more abundant compared to the average of the last 30 years). At end of April, the dominant blue pattern in all four provinces indicates that crops and rangelands have received sufficient rainfall to fulfil their water requirements. The light-yellow pattern that covers western Benguela indicates that average conditions were experienced in this season. The only part affected by dry conditions is the coast of Benguela, where rangelands are located. In the previous agricultural season, large parts of Bié were affected by very dry conditions, in contrast with this season. Figure 10. Spatial distribution of anomalies in the Water Satisfaction Index for crops since the start of the growing season until end of April 2020 (top) and for the same period in 2018/19 (bottom) (source: EC-JRC ASAP Warning Explorer). The value represented on the map is the number of standard deviations by which the WSI is above or below its mean value. For example, a score of -1.5 corresponds to a probability of 6.7% that such a low value occurs (i.e. every 15 years). 8 INFO BOX 2 - WATER SATISFACTION INDEX The Water Satisfaction Index (WSI) is an indicator of crop (or rangeland) performances based on the availability of water to the crop during the growing season. It uses a rainfall and evapotranspiration driven water balance accounting scheme to estimate water available to the plant. See more in ASAP WSI documentation. Figures 11, 12, 13 and 14 depict the rainfall received per dekad (10-day period) on the cropland area of each province, the corresponding historical average rainfall, as well as the cumulative rainfall for 2019/2020 and the cumulative historical average rainfall. As seen in Figure 11, rainfall conditions in Huambo were generally close to average throughout the season. The province experienced some dry spells in mid-January and mid-February, however above average rainfall in the previous dekads compensated for these deficits. In Bié (Figure 12), the start of season (until early January) was close to average but at end of May, the cumulative rainfall amount is slightly below-average due to a prolonged rainfall deficit experienced from mid-February to beginning of March. In Benguela, the temporal profile of cumulative rainfall amounts is well-above average throughout the season and exceeds the annual average by 13% at the end of May (Figure 13).