Response Growth Characteristics of two Sorghum Cultivars to the Application Timing of Nitrogen

Abstract

An experiment in field was carried out during the fall season of 2021 at the Agricultural Research Station of the College of Agriculture - Al-Muthanna University in the Al-Bandar area, which is 2 km from the center of the city of Samawah, in order to know the effect of application timing of nitrogen according to the different growth stages on growth characteristics of two sorghum cultivars .The experiment was applied according to the randomized complete block design (R.C.B.D.) with split plot arrangement and three replications, as two cultivars of the sorghum crop (Rabeh and Local) occupied the main panels, while the sub plots occupied application timing of nitrogen that included (half the quantity at sowing + half after 45 days of sowing, half at the stage of 4 leaves + half at the beginning of the boot stage, half at the stage of 4 leaves + half at the stage of 50 % flowering, and one third at the stage of 4 leaves + one third at the stage of boot + one third at the stage 50 % flowering ) and its symbol (N1, N2, N3, N4) respectively. The results have showed that the application timing of nitrogen N4 with one third at the stage of 4 leaves + one 2 MJAS third at the stage of boot + one third at the stage 50 % flowering was significantly superior, as it gave the least number of days from sowing until the 50% flowering stage (66.50 days ) and it gave the highest rates in the leaves content of nitrogen, growth crop rate (CGR), plant height and leaf area ,with averages (2.56% , 5.12 gm m-2 day-1 , 131.58 cm and 4087cm2 , respectively). The cultivars differed asignificantly in the most qualities of growth traits of the cultivar ( Rabeh) ) gave the highest average of leaves content of nitrogen, growth crop rate (CGR) and plant height,with averages (2.53% , 5.06 gm m-2 day1 and 129.41 cm, respectively . The interaction effect between the study factors was significant only in the trait of number of days from sowing until the 50% flowering .