IMPACT OF NITROGEN SOURCES AND IRRIGATION WITHHOLDING AT IDENTIFIED GROWTH STAGES OF HYBRID RICE UNDER DRILL SEEDED METHOD

Abstract

A field experiment was conducted in 2016 and 2017 seasons in a split split-plot design, with four replications, at the Experimental Farm of Rice Research Section located at Sakha Station, Kafr El-Sheikh Governorate. The current study aimed to investigate impact of nitrogen sources and irrigation withholding on hybrid rice. Nitrogen sources viz; urea, ammonium sulphate and ammonium nitrate were arranged in the main plots. Whereas, the time of water stress imposed at three identified growth stages viz; active tillering, panicle initiation and late booting were assigned in the sub plots. However, the duration of water stress viz; 6,8 and 10 days after disappearance of water from the soil surface were allocated in the sub sub-plots under drill seeded rice of Egyptian hybrid rice one. The main results could be summarized as following; the different studied nitrogen sources showed significant effect on rice growth, grain yield and yield attributes as well as protein content. Ammonium sulphate was found to be more beneficial, comparing with other nitrogen sources, since it gave the highest values of growth characteristics, yield attributes and grain yield. However, urea application came in the second rank. On contrary, ammonium nitrate showed less effectiveness. Withholding irrigation at certain growth stage greatly varied in its effect on rice growth, grain yield and yield components. Water withholding at panicle initiation had harmful effect on grain yield and most of the studied traits followed by withholding irrigation at active tillering. Irrigation withholding for 10 days (ADWSS) was more stressfulness while, 6 days withholding was less one. The application of 8 days withholding at late booting stage was considered the best water productivity. The most double interaction had significant effect on all studied traits in both seasons. The interaction results confirmed that ammonium sulphate had high affinity to alleviate the hazardous effect of water withholding at certain rice growth stages. Irrigation withholding at most sensitive rice growth for only 6 days could be applied without significant yield reduction.