ABDELMAGID ELMOBARAK1, ALI ELNAEM1, ADAM ADAM2, CHRISTIAN RICHTER3
1Agricultural Research Corporation (ARC), Land and Water Research Center, Sudan
2University of Gezira, Faculty of Agricultural Sciences, Sudan
3University of Kassel, Institute of Crop Science, Witzenhausen, Germany
Wheat (Triticum aestivum L.) cultivation in Sudan expanded in the last decades to latitudes lower than 15 °N as a winter crop, occupying the largest area in Sudanese irrigated schemes, and it is the second most important cereal crop after sorghum in the country. The demand for wheat increased due to urbanisation, but there is a large deficit of production compared to consumption. Average wheat yields in Sudan are very low, due to climatical and to production factors. Nowadays, many different fertiliser forms are introduced in Sudan to raise wheat yields.
The objective of our study was to test the effect of different nitrogen fertilisers on wheat yield and quality. The fertilisers used were urea, Nitrophoska, ammonium sulphate and ammonium sulphate nitrate. N, P, K and S were applied in same amounts on all plots, only the N fertiliser form was different. The experiment was conducted on two typical wheat soils of Sudan, a Vertisol, non saline and non sodic, in the Gezira scheme in the Center of Sudan, latitude 14.3 °N, and an Aridisol, non saline, but slightly sodic, latitude 15.5 °N, in the dryer region near Karthoum. The wheat variety Debeira was sown in two seasons, on November 15 of 2001 and of 2002. Two levels of fertiliser were applied: 1 N and 2 N (1N = 43kg N ha-1).
Our results showed a significant increase of grain yield and of grain protein content with increasing nitrogen level from all fertiliser sources on both soils and in both seasons. Nitrophoska outyielded the other nitrogen sources, followed by urea, ammonium sulphate nitrate and ammonium sulphate. Maybe there were less NH3-losses by volatisation from Nitrophoska than from the other fertilisers. These NH3-losses are severe in Central and Northern Sudan, as most of these soils are high-pH soils.
The Gezira Vertisol, situated more in the South, gave a higher wheat grain yield, but a lower grain protein content than the Aridisol in the dryer climate near Khartoum. So, different climates and different soils are responsible for different yield and protein contents of wheat in the study areas of Sudan.
Keywords: Aridisol, nitrogen fertilisers, vertisol, wheat