Submitted to: Journal of Tropical Agriculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/17/2005
Publication Date: 7/1/2005
Citation: Bartholomew, P.W., Mohammed, O.M., Hamid, M.T., Mahir, M. 2003. Irrigated forage production in the central clay plains of Sudan. Journal of Tropical Agriculture. 80(3):135-145. Interpretive Summary: In common with other areas of sub-Sahelian Africa the productivity of ruminant livestock in Sudan is limited by feed shortages over a significant period of the year. Forage supplies are plentiful during the 3-4 month rainy season but decline in quantity and quality through the dry season. Improvement in forage production techniques in central Sudan is necessary to promote livestock production to meet demands of expanding domestic and regional markets, but information on management needs of forage crops is not readily available. A series of field experiments was carried out to determine fertilizer, seed rate, growth period and irrigation management effects on yields of a range of potential forage crops. Among the crops tested whole-crop grain sorghum produced the most forage, and yield was increased by an average of 21 lb of dry forage for each lb of nitrogen fertilizer applied. Wheat grown for forage between November and February was more productive, and less subject to insect pest damage, than any warm season crop grown at that time of year. Seed needs for forage could be reduced by up to half by irrigating land before cultivation and sowing. Farmers in central Sudan could increase annual forage output and improve seasonal distribution by using wheat and grain sorghum as whole-crop forages. However, efforts to increase production of forage during the hot- dry season are not recommended because of the low efficiency of water use at this time of year. The best way to increase availability of forage during the dry season is by conservation of surplus forage grown in the rainy season and the following cool season.
Technical Abstract: Management needs of crops grown for forage in the central clay plains of Sudan were investigated. Reliable seed rate recommendations for a range of forages were difficult to establish because of highly variable field emergence. However, for sorghum it appeared that 95% of maximum forage yield could be obtained at an established crop density of 55 plants.m-2. Irrigation prior to cultivation and sowing during the dry season nearly doubled field emergence of sorghum and wheat and a similar degree of improvement in emergence was achieved with planting sorghum at 2cm depth rather than sowing broadcast. Sorghum grown for forage showed a consistent response to applied nitrogen at an average 21.0 kg DM.kg-1N up to an application of 75 kg N.ha-1. Forage production responses to phosphorus application were more variable with an average of 12.6 kg DM.kg-1P2O5 within a range of 0.75-40.6 kg DM.kg-1P2O5. Among a range of species the most productive short-term forage crop was grain sorghum cv. Umbanein, which produced on average 17% more DM than the traditional forage sorghum cv. Abu Sabein when harvested as a whole-crop for forage. It is suggested that a policy of seasonal production of irrigated forage in central Sudan, focused on the July-January period, should be encouraged in order to maximize efficiency of use of limited water supplies.