Advising on the 2003/2004 summer season: Statement from the National Agricultural Risk and Disaster DoA No March 2004

Transcription

1 Advising on the 2003/2004 summer season: Statement from the National Agricultural Risk and Disaster DoA No.7 23 March 2004 In the light of the seasonal outlook as produced by the South African Weather Service (SAWS), Check I below, the following advisory guidelines is suggested. It is emphasized that these advisories are broad guidelines and should be interpreted considering the local aspects of the region such as soil types, cultural preferences and farming systems. Depending on the particular region, the prioritization of the guidelines will differ. The basic strategy to follow would be to minimize and diversify risk, optimize soil water availability and to manage the renewable resources (rain water and grazing) to uphold farming objectives. Longterm mitigation strategies should be considered by implementing techniques to enhance in-field water harvesting by reducing run-off and improving infiltration. Reduced tillage methods are very important in this regard, as is basin tillage, to capture rainwater in the drier areas. The provinces should further package the information according to their language preference and if possible use local radio station in disseminating the information. I. SAWS OUTLOOK SYNOPSIS: The weak positive (warmer than usual )sea-surface temperature anomalies in the tropical Pacific Ocean currently have negligible effect on the atmosphere. 1. RAINFALL March + April + May 2004 There is a 45% probability of below-normal rainfall conditions to occur over the north-eastern and south-western parts of the forecast region, with a 35% probability of near-normal. A 40% probability of near-normal rainfall conditions is expected over the central parts of the forecast region, with a 35% probability of below-normal. 1

2 May + June + July 2004 There is a 45% probability of below normal rainfall to occur over the southwestern Cape with a 35% probability of near-normal conditions. Near- normal conditions with a probability of 40% are expected over the remainder of the forecast region with a 35% probability of below normal. 2. TEMPERATURE March + April + May 2004 A 40% probability of normal temperatures is expected over the entire forecast region. There is a 35% probability of below-normal temperatures over the southern part and a 35% probability of above-normal temperatures over the northern part. 2

3 May + June + July 2004 A 40% probability of normal temperatures is forecast for the entire region, with a 35% probability of below-normal conditions. Weather and Climate The potential of climate prediction arises NOT from timing and location of individual weather events, but for averages over months and seasons. Climate forecasts are distinctly different from weather forecasts, because they cover relatively large regions over a long period of time. The weather at particular locations and at specific times may sometimes appear to contradict the climate forecast. The climate of southern Africa is influenced by, amongst others, the variability in sea-surface temperature (SST) in the region of the equatorial Pacific Ocean. El Niño is associated with anomalously high SSTs in this region and La Niña with anomalously low SSTs. SSTs during the past month (observed): November SST anomalies in the Eastern Equatorial Pacific Ocean were slightly higher than normal. SSTs during the coming months (forecast): Slightly warmer than average conditions over the Eastern Equatorial Pacific Ocean are likely to persist during the next few months. Changes in the atmosphere are amongst others described by means of the Southern Oscillation Index (SOI). The SOI value for November 1982, prior to the 1982/83 El Niño was -5.1 while -2.3 in November 1997, prior to the 1997/98 El Niño. 3

4 CONCLUSIONS 1. The weak positive sea-surface temperature anomalies in the tropical Pacific Ocean currently have a negligible effect on the atmosphere. 2. A high probability of below normal rainfall conditions are expected over the north eastern and south western parts of the forecast region with the probability of near normal rainfall conditions over the central part of the country. 3. A high probability of normal temperatures is expected over the entire forecast region. 4. The frost is expected to be a threat as the cool conditions might be experienced early this year and measures should be in place for the frost prone areas. 5. Regularly obtain the weather and monthly updated seasonal forecasts on the SAWS web. II. Current Conditions: Figure 1 Figure 2 4

5 Figure 3 Figure 4 In January 2004, the country received patches of normal to above normal rainfall conditions with the patches of below normal rainfall in the central interior. In February 2004, the country received patches of normal to above normal rainfall except most parts of the Northern and western Cape. The western part of Free State, northeastern part of KwaZulu Natal and the coastal area of Eastern Cape received below normal rainfall. The long-term shows that the western part of the country received above normal rainfall conditions with the normal rainfall conditions in the border between Western Cape and Northern cape. In general, the eastern part of the country received normal to above normal rainfall conditions with the scattered patches of below normal rainfall conditions. In the first ten days of March, most areas of the country received normal to above normal rainfall with the below normal rainfall in the northern parts of Northern cape and North West as well as northeastern parts of Mpumalanga and KwaZulu Natal. The above maps show the percentage of normal rainfall for January 2004(Figure 1, SAWS web), February 2004 (Figure 2, SAWS web), the season July 2003 to February 2004 (Figure 3, SAWS web) and 1-10 March 2004 (Figure 4, SAWS web). The NDVI reflects an improved vegetation activity throughout the country. There is a widespread normal vegetation growth in the provinces of Limpopo, Mpumalanga, KwaZulu Natal, Eastern Cape, Western Cape and the Free State. The rest of the Provinces reflect a balanced mixture of normal and below normal vegetation conditions, with some small spots of above normal conditions in Eastern Cape, KwaZulu Natal and Northern Cape. However, below normal conditions in the North West, Free State and the Western part of KwaZulu Natal are fully inclusive. This is because of the atmospheric attenuation of reflected radiation caused by clouds. TROPICAL CYCLONE The Tropical Cyclone Galifo caused people their lives in Madagascar. It was traveling to the Mozambique Channel but turned away to Madagascar, as a result it did not affect South African weather. CONDITIONS IN THE PROVINCES Mpumalanga The Province is still receiving some good rains as a result the levels of dams and flow of water in the rivers have improved. Most of the farmers who planted their maize during late December are expecting good yields should the rain continues. The veld condition is good due to received rains and as a result the livestock is also in good condition. 5

6 Free State The drought situation in the Free State has stabilized due to widespread of rains that occurred from February and March. The veld has reacted well to the rain but production is lower than normal. There are some areas in the southwestern part of the Province that have critical feed shortages, which might also occur during winter. The condition of summer crops as well as the condition of stock is good. There is a shortage of a livestock drinking water in some areas particularly in the eastern part of Free State. Eastern Cape The Province has received some showers that covered almost the whole Province but they were not significant to improve the veld condition. Levels of water in dams have not improved after the showers received. Animals have to travel long distances to drink water because of its scarcity. There is a concern that with winter season approaching the veld and pasture conditions might not improve. The livestock condition is poor and deteriorating due to the lack of forage in the veld. Western Cape The below normal rainfall was experienced in the western parts of the Province. The harvesting of stone and pome fruits are about to finish and farmers are busy with the pressing of grapes for wine production. Generally the veld condition is poor due to the shortage of rainfall whereas the irrigated pastures are in good conditions. The small stock ranges from reasonable to good. The farmers are decreasing their stock due dry conditions experienced. The cattle are in good conditions. The level of dams are increasing even though are less than last year this time. Kwazulu Natal The whole Province received the rain showers in the month of February. The veld is in good condition but shorter as compared to last year this time that will make shortages in the coming winter. The crop is in below normal condition ranging from vegetable to sugar cane. The livestock is in good condition in the commercial farming and the communal is in bad condition. The water levels in springs, boreholes and earth dams are improving due to the received rainfall. Limpopo The Province is receiving some good rains almost in all drought stricken districts. The veld and dam conditions have improved after the rains received. The crops that were planted from mid December 2003 to the 15 January 2004 are expecting good harvest while those who planted earlier have lost their crops. The livestock condition is also improving very well. Northern Cape The Province has received some below normal to normal rainfall. Most of the crops were not planted due to lack of rainfall. The wine grape production is fairly 6

7 normal and export grapes are below normal due to rain, hail, frost damage and high exchange rate. The maize crops that have been planted in the Pixley Kaseme are in good condition. The livestock condition is normal to below normal and it is deteriorating in Namaqualand due to overgrazing. The farmers are also experiencing high exchange rates Gauteng The Province received some widespread showers during the month of February and first week of March in all areas. The good rains significantly contributed towards improved veld conditions in the Province and as a result the livestock is in good condition. The planted pastures are in very good conditions in Magaliesburg and Vereeniging areas. Many farmers had a good harvest on dry land maize due to the rains received from December until now. The vegetable production under irrigation was also good. North West The province received sufficient rainfall except the western region. The crop condition is not in very good conditions due to the impact of drought but promising after the late rains received. The livestock condition is good in the commercial farming while poor in the communal farming. The livestock conditions have also improved in the Mafikeng and Makgobistad areas, as no sign of food and water stress are available. In the Bophirima area, poor veld management still persists in the communal sector. The veld conditions are improving in the Central, Southern and Bojanala regions due to adequate rainfall received. III. SADC REGION According to the Ten-day drought watch for Southern Africa, the moderate to heavy rains was received across much of the central sector. Light rains were received over the northern sector whereas southwestern parts remained dry. The forecast shows that widespread of moderate to heavy rains are expected over much of the central sector during the outlook period. Light rains are expected over northern sector and southeastern parts. The dry conditions are expected to persist in the southwestern parts. The floods were experienced in the upper Zambezi basin area of Zambia that submerged some buildings and crops. Tropical low occurred in the southeastern Zimbabwe which moved to Limpopo and caused heavy rains that resulted to floods in some areas, the other one occurred over Botswana and moved to southward which caused heavy rains in most areas of North West, Gauteng, Mpumalanga and Limpopo. The islanders in Botswana s Okavango Delta have denied vacating their islands despite being surrounded by floods. IV. Some strategies that could be followed: 7

8 A. Rain-fed crop production. Soil choice: Do not cultivate soils that are marginal for crop production, where possible, such as: Shallow soils and soils with a low water holding capacity as this poses the risk of crop failure. Give preference, where applicable, to arable soils with ground or perched water tables. Land preparation: Avoid, where possible, soils with pronounced plough pans. Ripping can break Plough pans and thus increase access of roots to stored water and nutrients. This action should be considered carefully and as a long-term strategy to reduce risk. Cover soils by mulching, as this action will enhance infiltration and reduce unproductive evaporative losses. Where possible, add organic material to the soil, this action enhances water infiltration and storage. Crop choice: Set conservative yield goals by; o Choosing drought resistant crops and cultivars. o Considering short season varieties in view of limited water availability. o Adopting conservative planting densities. o Adopting conservative fertilizer strategies. Spread the planting dates within the normal planting window. Consider diverse crops rather than cultivating single crops. As the optimal planting date has passed in most regions; o Adjust yield goals, o If not planted yet, reconsider strategies. If the risks outweigh the options, consider fallowing the fields to allow soil moisture buildup towards the next season. Crop management: Adapt top dressing of nitrogen fertilizers to seasonal progression. Control weeds aggressively, with at least weekly inspections. Regular and strict scouting for pests and diseases to minimize expenditure on chemical control. Do not expand land under crop production unnecessarily. Do not experiment with the new and unknown and avoid unnecessary capital investments. B. Domestic and home garden water use: Conserve existing water supplies 8

9 Eradicate water weeds Limit water waste and losses Repair leaking pipes Re-use water and retain high quality Additional sources of water must be used at this stage C. Stock farming: Spread water points evenly through grazing areas First graze areas where vegetation already shed leaves Plant hardy trees/shrubs for browse. Keep well adapted breeds of livestock Provide suitable licks and make dry range grasses palatable During worse conditions, take animals to the camps and feed them Wean early and raise young animals intensively Postpone the mating period during extremely dry conditions Market surplus stocks and cull poor producers when feed resources run out. Maintain young best females Control stock numbers to prevent overgrazing and to save the veld for the coming winter season. Control animal diseases and parasites. Feed pregnant and lactating animals better. Prevent veld fires. Evaluate carrying capacity of their available grazing and apply the appropriate stocking rates accordingly. D. Irrigation farming: Remove all weeds containing seeds, but keep other vegetative rests on the land because that will reduce evaporation. Obtain the desired seeds for the crops to be planted. Check and repair all tools and machinery. Consider making of bunds or other features to increase infiltration and to reduce. Irrigate during cool conditions to avoid evapotranspiration. Adhere to the water restrictions at all times Farmers are warned that under the current climate conditions of wet and below normal temperatures expected, the areas that are prone to frost might have problems. The PDAs must monitor the grazing capacity of livestock in the Provinces. The contingency plan needs to be in place for frost. The rainfall forecast shows a high probability of normal centrally and as the country received below normal rainfall for the first half of the season, it might be that some cultivated land could have low soil moisture. This has 9

10 to be monitored before deciding which land to cultivate and what cultivars to plant. Preference should be given to fallowed land, where the soil moisture is still available. The good rains had been falling since January until now in most parts of the country that might relieve the dry condition. The below normal temperatures are expected at the beginning of winter and frost days can be expected earlier. The current weather and climatic conditions may result in some plant and animal diseases experienced in certain areas. The PDAs through the extension services should continuously monitor, evaluate and report current Agricultural Risk and Disaster issues. Furthermore the advisory should be disseminated widely. For more information contact: - NDA, Directorate: Agricultural Risk and Disaster Management Private Bag X250 Pretoria 0001 Tel: /56 Fax: secsm@nda.agric.za ARC-Institute for Soil, Climate and Water Private Bag X79 Pretoria 0001 Tel: Fax: info@iscw.agric.za 10