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Sudan Journal of Agricultural Research

Water requirements of the main crops in the Gezira Scheme

Sirelkhatim H. Ahmed, Abdelhadi A. W., Elhadi M. A. and Hussein S. Adam

Abstract

Information on water recourses of the Sudan was reviewed. Average annual flow of the Nile is about 84 bcm, measured at Aswan. According to the 1959 Nile Water Agreement between Sudan and Egypt, respective shares of the two countries are 18.5 and 55.5 bcm. Currently, annual amount of water available to the Sudan from national and international sources is about 35.5 to 37 bcm. Agricultural sector consumes more than 90 percent of this amount. The Ministry of Irrigation and Water Recourses, under the Long Term Agricultural Strategy, projected that the irrigation water needs, human and animal consumption, domestic and other uses and evaporative losses by the year 2027 will be about 59.2 bcm. This implies the need for very efficient use of water resources
The main objective of this paper is to update reference evapotranspiration (ETo) values to be used for the estimation of crop water requirements of the main crops in the Gezira. Long term (1970-2000), ten-day average meteorological data for Wad Medani meteorological station (Lat.14.4 N: Long. 33.5 E) was used. Collected data included maximum and minimum temperature, relative humidity, wind speed, rainfall and sunshine hours. FAO paper (56) methodology was used to estimate daily duration of maximum sunshine hours, extraterrestrial solar radiation, evaporation from free water surface (Eo) according to Penman (1948) and Penman-Monteith reference evapotranspiration (ETo). The ratio Eo/ETo rounded to the first decimal was 1.1 during the period between June and September and 1.2 for the rest of the year. Crop water requirements for different sowing dates were estimated as the product of either Eo or ETo by the appropriate crop factor (coefficient). Studied crops were cotton, wheat, sorghum, groundnuts, sesame, summer fodder, sugar cane, vegetables, fruit trees, and forests. The highest seasonal amount required was by sugar cane (12490-12410 m3/fed) followed by that of extra long staple cotton ELS (Gossypium barbadense), (5110-5320 m3/fed) and medium staple cotton MS (Gossypium hirsutum), (3645-3680 m3/fed). The lowest amount was required by sorghum, ST (2265-2310 m3/fed). Wheat requires (2555-2760 m3/fed) while summer fodders require (3205-3430 m3/fed). Long and short-term groundnut water requirements is estimated at (3325-3420) and (2430-2600) m3/fed, respectively. Irrigated sesame requires about (2470-2570) m3/fed. For crops grown during the rainy season, expected rainfall should be subtracted from estimated crop water requirements. Also, due allowance should be made for expected seepage, canal evaporation and other losses. Estimated crop water requirements dose not include planting water requirements.
 

Sudan Journal of Agricultural Research Vol. 9 (2007) PP. 67-89