RESPONSE OF SUNFLOWER YIELD AND CROP -WATER RELATIONS TO LIQUID AMMONIA FERTILIZATION LEVELS AND IRRIGATION WATER QUANTITIES

Two field trials were conducted at Tamiea Agric. Res. Station, Fayoum Governorate, Egypt during 2012 and 2013 summer seasons to investigate the effect of three N fertilization rates, i.e. N1 : 40, N2: 50, and N3: 60 kg/fed as liquid ammonia (one kg of liquid ammonia contains 82.5% N) combined with three levels of irrigation water quantities e.g. 2200, 2500 and 2800 m3/fed distributed during the growing season onto six irrigation events. The adopted treatments were assessed in a strip- plot design with four replications on yield components, yield and some crop water relations. The main results obtained were as follows:•Seed yield and yield components were significantly affected due to N fertilization levels and applied irrigation water quantities in 1st and 2nd seasons.•The highest averages of plant height, head diameter and weight, seed weight/head, 100-seed weight and seed yields (792.15 and 816.49N kg/fed in 2012 and 2013 seasons, respectively), were detected from injecting the soil with liquid ammonia as 60 kgNfed-1 level and irrigating with 2800 m3 water/fed whereas the lowest yield components, and seed yield (565.61 and 580.52 kg/fed) were obtained with 40 kgNfed-1 level and applying 2200 m3 water/fed.•The highest seed oil content i.e. 42.23 and 42.31 % in 2012 and 2013 seasons, respectively. were obtained due to 40 kgNfed-1 level.and 2800 m3 water /fed rate interaction.•Seasonal evapotranspiration (ETC) was maximum (50.76 and 51.77 cm in 2012 and 2013) with applying 60 kgNfed-1 level and irrigating at 2800 m3/fed water interaction. The monthly crop coefficients (KC) under the highest yielding interaction were 0.57, 0.76, 0.95 and 0.62 for July, August, September and October, respectively, (means of the two seasons).Applying 50 kgN fed-1 level and irrigating with 2200 m3/ fed rate is the most efficient interaction for water use with values comprised 0.374 and 0.382 kg seeds/ water consumed in 2012 and 2013 seasons, respectively. Moreover, the highest water productivity (WP) values i.e. 0.321 kg seeds/m water applied, respectively, in 2012 and 2013 seasons were recorded due to 60 Nkg fed-1 level and 2200 m3/fed water interaction.