EFFECT OF SPLIT APPLICATION OF NITROGEN FERTILIZER ON MORPHO-PHYSIOLOGICAL ATTRIBUTES AND GRAIN YIELD OF BROADCAST SEEDED EGYPTIAN HYBRID RICE (Ι)

Abstract

An experiment was carried out at the Experimental Farm of Rice Research and Training Center (RRTC), Sakha, Kafr El-Sheikh, Egypt, during 2011 and 2012 seasons. The experiment was laid out in a split plot design with four replications. The main plots were devoted to the nitrogen level 220kg N/ha in form of urea (46.5% N). The sub-plots were allocated to the six times of nitrogen application to assess the effect of six nitrogen application treatments, viz., T_1: (2⁄(3 ) as B ( basal ) + 1⁄3 at PI ( panicle initiation)), T_2: (1⁄3 as B + 1⁄3 at MT (mid-tillering) + 1⁄3 at PI.)), T_3:(1⁄2 as B + 1⁄4 at MT + 1⁄4 at PI.)), T_4:(1⁄4 as B + 1⁄4 at MT + 1⁄4 at PI + 1⁄4 at BT (booting)), T_5:(1⁄4 as B + 1⁄4 at MT + 1⁄4 at BT + 1⁄4 at CH (complete heading)), and T_6:(1⁄4 as B + 1⁄4 at MT + 1⁄4 at PI + 1⁄4 at F ( flowering)) on morpho-physiological attributes and grain yield of Egyptian hybrid rice (1) under broadcast seeded-rice. The results revealed that nitrogen levels caused significant increases in all morpho-physiological attributes and grain yield of Egyptian hybrid rice (1), except for number of primary branches/panicle, number of panicle/m², panicle weight and 1000-grain weight in both seasons. Leaf area index and dry matter production at flowering were significantly increased in first and second seasons, respectively, Increasing N-level up to 220kg N/ha significantly increased number of unfilled grains/panicle and straw yield t/ha. In addition, application of 165kg N/ha produced the highest values of number of filled grains/panicle, grain yield t/ha and harvest index in both seasons. Moreover, It was observed that the highest estimated values of dry matter production at panicle initiation and straw yield; and the lowest number of panicles/m² were recorded in the first treatment (T_1), without significant differences with the 〖(T〗_(3 )) and 〖(T〗_(5 )) treatments in both seasons. The highest dry matter production at flowering, LAI at flowering, chlorophyll content in flag leaf, days to 50% heading, plant height at harvest, number of primary branches/panicle, panicle weight, heaviest 1000-grain weight, harvest index and grain yield were exhibited in 〖(T〗_(6 )) in both seasons, The interaction between nitrogen levels and time of nitrogen application had significant effect on dry matter production ( g/m²) at panicle initiation, leaf area index at both panicle initiation and at flowering, chlorophyll content in flag leaf and number of tillers/m², number of filled grains/panicle in both seasons and number of unfilled grains/panicle in the second season. From the obtained results, it could be recommended that splitting of N-fertilizer application with the rate of 165 kg/ha in four equal doses i.e. as basal application, mid-tillering, panicle initiation and at the flowering stages were played a remarkable role for achievement of high yield production from Egyptian hybrid (1) rice genotype, when it grown under broadcast seeded rice under normal soil in Egypt.