ENHANCING THE PROFICIENCY OF WATER USE IN WHEAT THROUGH NITROGEN FORMS, IRRIGATION INTERVALS AND SOIL CONDITIONERS S.M.M. ABDOU 1 * , R. AHMED AZZA 1 , S. NARESH KUMAR 2 AND F.R.M. FARRAG 1 1 Agricultural Research Centre, Soil, Water and Environment Research Institute, Giza, Egypt 2 Centre for Environment Science and Climate Resilient Agriculture, ICAR-Indian Agricultural Research Institute, New Delhi, 110012, India ABSTRACT Field experiments were carried out at the Tameia Agricultural Research Station, Fayoum Governorate, Egypt, during the 2013/14 and 2014/15 seasons in order to study the impact of nitrogen fertilization forms, irrigation intervals and some soil con- ditioners on the yield, yield components and crop water relations of wheat (Giza 168). Two nitrogen forms with three irrigation intervals, i.e. I 1 : irrigation at 14 days, I 2 : 21 days and I 3 : 28 days with soil conditioners at the rate of 11.9 t ha -1 , i.e. C 1 control (without any addition), C 2 : compost, C 3 : rice straw and C 4 : sawdust with three replications in a split-split plot design. Results indicate that the highest wheat grain yields in both years were detected from a combination of applying liquid ammonia gas, irrigation at 14-day intervals and addition of compost. This treatment also gave higher values for yield components, uptake of nitrogen, phosphorus and potassium and their concentration in the grain. Further, it resulted in highest values for the consump- tive use of water as well as water productivity. Thus, a combination of applying liquid ammonia gas, irrigation at 14-day in- tervals and addition of compost can be adopted in wider areas in Egypt for enhanced wheat grain yield. © 2018 John Wiley & Sons, Ltd. key words: wheat yield; liquid ammonia; ammonium nitrate; soil conditioners; water consumptive use; water productivity Received 15 May 2017; Revised 22 May 2018; Accepted 23 May 2018 INTRODUCTION Wheat is considered to be the most important cereal crop in Egypt. It is grown over 1.42 Mha (million hectares) with a production of 9.2 Mt at an average productivity of 6.51 t ha -1 (Food and Agriculture Organization of the United Nations (FAO) 2016). Although Egypt ranks among the top 12 countries for wheat productivity, next only to European countries, there is a huge gap between domestic production and demand due to the rapid increase in population. Cur- rently, farmers are using excessive fertilizer and irrigation, which may lead to unsustainable production in the near fu- ture. Therefore, more effort must be exerted to increase its production per unit area with respect to proper inputs, in par- ticular water optimization, nitrogen (N) fertilizer manage- ment and improving soil physical and chemical properties by adding soil conditioners. Nitrogen fertilization is essential for cereal crops as N is very important for cell building and size, photosynthetic activity and protein assim- ilation rates in plants (King et al. 2003). The form of N that gives higher plant growth and yield must be used to obtain higher nitrogen use efficiency (NUE). From the economic point of view, anhydrous ammonia is preferable as an N source in order to reduce the cost of N fertilization. In Egypt, the production of anhydrous ammonia has recently been increasing to replace ammonium nitrate (AN) and urea fertilizers. Application of organic and inorganic fertilizers together led to an increase in macronutrient uptake and con- tent in wheat (Patel et al. 2014). Furthermore, an optimum dose of N fertilizers could improve water productivity (Shaaban 2006; Wang et al. 2012). Anhydrous ammonia slightly increased the consumptive use (CU) of water (~2.4%) and grain yield in wheat, whereas water productiv- ity showed different trends in the two seasons compared with the 179 kg N ha -1 rate (Abdelkhalek et al. 2015). In Egypt, because of the prevailing arid climate, irrigation is the most important input for crop production, and irriga- tion water shortage significantly affects both productivity and profitability. Irrigating wheat at 35% available soil *Correspondence to: S.M.M. Abdou, Soil, Water and Environment Re- search Institute, Agricultural Research Centre, Giza, Egypt. E-mail: dr_samehabdou2004@yahoo.com Améliorer la performance de l’utilisation de l’eau dans le blé à travers les formes d’azote, les intervalles d’irrigation et les conditionneurs de sol IRRIGATION AND DRAINAGE Irrig. and Drain. (2018) Published online in Wiley Online Library (wileyonlinelibrary.com) DOI: 10.1002/ird.2258 © 2018 John Wiley & Sons, Ltd.