Competitive Response of Wheat (Triticum aestivum L.) and Wild Mustard (Sinapis arvensis L.) to Nitrogen under Saline Conditions

A pot experiment was carried out to investigate competition of wheat against wild mustard affected by salinity and N fertilizer levels، in Ramin Agriculture and Natural Resources University of Khouzestan greenhouses during 2012-2013. Experiment was Factorial in a completely randomized design in four replication. Experimental factors in trials was nitrogen levels (0، 60، 120 and 180 kg. ha-1 from Urea fertilizer sources) and irrigation water salinity (0، 3، 6 and 9 ds. m-1 by NaCl). Result show that the highest dry matter of wheat was obtained in 120 and 180 kg N. ha-1 without salinity. In the rate of 120 kg N. ha-1، there was no significant difference between salinity levels، in term of wheat dry matter. The lowest dry matter of wheat was observed in 9 ds. m-1 without nitrogen. Increase of nitrogen levels in saline conditions، caused to alleviate effect of salinity stress on wheat growth. However، further increase of N levels caused to decrease the competition ability of wheat against wild mustard and that failed to reduce the high levels of salinity reduces of wheat growth.