EFFECT OF DIFFERENT FORMS OF N- FERTILIZER AND WATER REGIME ON ONION PRODUCTION AND SOME CROP - WATER RELATIONS

Abstract

A field experiment was conducted at Dar El- Ramad, Fayoum District, Fayoum, Egypt during 2008/2009 and 2009/2010 seasons to study the effect of N fertilizer forms, i.e. F1: mineral N fertilizer form at the rate of 100 unit N fed-1 (as ammonium nitrate 33.0% N), F2: bio-fertilizer(biogena)+50 unit N/fed, as mineral fertilizer and F3: organic form as chicken manure and irrigation regime treatments, i.e. I1: irrigation at 40% Available Soil Moisture Depletion (ASMD), I2: irrigation at 60% ASMD and I3: irrigation at 80% ASMD on yield, yield components and some crop-water relations of onion crop (Giza 20 cv.). The split-plot design with four replications was used, where N forms were occupied the main plots while the split ones were allocated to irrigation regimes . The main obtained results were as follows: 1- Using mineral N form and irrigation at 40% ASMD. gave the highest averages of dry bulbs weight, dry bulbs diameter and dry bulbs yield (17.22 and 16.95 t dry bulbs fed-1) in the two successive seasons. The lowest averages of yield and its components were obtained from using FYM fertilizer form and irrigation at 80% ASMD in both seasons. 2- Seasonal consumptive use (ETC) averages were 41.18 and 40.45 cm in 2008/2009 and 2009/2010 seasons, respectively. The highest ETc values, i.e. 45.49 and 44.48 cm were recorded from F1I1 interaction ,in 2008/2009 and 2009 /2010 seasons, respectively, whereas the lowest values, i.e. 37.24 and 36.57cm in the two successive seasons were resulted from F3I3 interaction. 3- Daily ETC rates were low during Dec., then increased during Jan. and Feb., to reach its interaction maximum values during March and then declined again at April till harvesting. The values of daily ETc were decreased by applying organic or bio-fertilizer forms and increased irrigation regime more than 40% ASMD in the two growing season's months. The crop coefficient (KC) values were 0.45, 0.66, 0.75, 0.94, 0.63 and 0.43 (averages of the two seasons) for Dec., Jan., Feb., Mar., Apr. and May, respectively. 4- The highest water use efficiency values i.e. 9.054 and 8.998 kg dry bulb yield m-3 water consumed were obtained from irrigation at 40% ASMD as interacted with N fertilizer in the mineral form in 2008/2009 and 2009/2010 seasons. However, on managing the limited water resources efficiently under the present experiment conditions, it is advisable to irrigate the onion crop at 60% ASMD with mineral N fertilizer form in order to obtain reasonable figures for water productivity and to conserve irrigation water.