اثرات كم آبياري و نيتروژن بر عملكرد و اجزاي عملكرد گندم

Effects of Deficit Irrigation and Nitrogen Rates on Yield and Yield Components of Wheat

In order to investigate the effects of deficit irrigation and nitrogen rates on yield and yield components of wheat, a field experiment was conducted as split plots arranged in a randomized complete block design (RCBD) with three replications during 2000-2002 at Maragheh Agricultural Research Station of DART. The treatments included four levels of irrigation (Rainfed ,1/3, 2/3 and 3/3 of full irrigation) as main plots and five N rates (0 ,30 ,60 ,90 and 120 kg N/ha) as sub-plots. Grain, straw and biological yields, harvest index, plant height, number of seeds per spikes, spike per m2 and 1000kw were measured from the middle of each plot. Results showed that there are positive significant correlations between grain yield and all variables.Yields at rainfed conditions varied with the amount of seasonal rainfall and its distribution, with all main factors having significant effects. At irrigated conditions, crop response differences were generally significant by using up to 60-90 kg N/ha. Optimum results for deficit irrigation was obtained for 2/3 of full irrigation combined with 90 kg N/ha which had maximum water use efficiency (27.92 kg seed yield/ ha/l mm used water).