18th International Soil Meeting (ISM) on “Soils Sustaining Life on Earth, Managing Soil and Technology”, Şanlıurfa, Turkey, 22 - 26 May 2006, vol.2, pp.946-950
Effects of Nitrogen Fertilization Rates and Irrigation Programmes on Cotton (Gossypium ssp.) Yield
In Aegean region, cotton is one of the main crops with 215000 ha of planted area. The objective of this study was to determine the optimum nitrogen fertilization and irrigation rates for cotton plant under drought stress conditions. An experiment was set up with six irrigation treatments as main plots and three nitrogen rates (0-60-120 kg ha-1) as subplots, with 4 replications. Uptakes of N and P by different plant parts, dry weights and cotton yields were determined under different stess conditions. Increments in N-rates increased the N concentration of all plant parts. However the same trend was not observed for P contents which showed a decreasing trend or constant level with increased N application. Dry weight increased with respect to irrigation and fertilization treatments. On the other hand N- abd P-uptakes completely depended on dry weight increases. Results showed that 60 kg ha-1 N was sufficient under the conditions where water shortages are prevailing. It is also concluded that creating stress in boll shell formation period didn't significantly affect the cotton yield.
Key words: Gossypium ssp. / N-fertilization / drought stress / cotton yield