Effect Levels of Nitrogen Fertilizer and Seed Rate on some Growth Stages of Two Cultivars of Barley Horedum vulgare
Authors: Al-Ziyaidi Esra Rahi Sihud , Fadel Hassan Abbas , Salman Razzaq Abdul Rab Jaafar 
Published: September 2023

Abstract
A field experiment was carried out at the second agricultural research station (Al-Bandar) affiliated to the College of Agriculture / Al-Muthanna University, for the season (2020-2021), with the aim of knowing the effect of nitrogen fertilization levels and seeds rate on the production of dry matter for some growth stages of two varieties of barley, and the experiment was applied in order Split plots according to the randomized complete block design with three replications, and the number of experimental units reached 30 experimental units. The experiment included the main factor of four levels of fertilization, which are (0, 50, 100, and 150 kg h-1), and the secondary factor included five seeds rate, which are (20, 40, 60, 80, 100, and 120 kg h-1), and the third factor included two varieties of barley (ACSAD and IPA 265). The results showed that the levels of nitrogen were significantly superior in most of the studied traits, where the fourth level excelled in recording the highest average of the characteristic of the crop growth rate from elongation to flowering and the number of tillers (161.40 g / m2 / week and 348.20 strips m2), while the third level excelled and recorded the highest average For both traits, the crop growth rate from tillering to elongation was (43.620 g/m2/week). The first level excelled in giving the highest average of the relative growth rate from tillering to elongation (1.94 g/m2/week). As for the seeds rate, the third level of sowing excelled in giving the highest average characteristic of the crop growth rate from elongation to flowering (150.80 g / m2 / week) and the fourth level excelled in giving the highest average of the two characteristics of the crop growth rate from tillering to elongation (41.260 g / m2 / week) and the characteristic of the relative growth rate from tillering to elongation (1.90 g / m2 / week). As for the fifth seeds rate, it excelled in the number of tillers, if it reached the highest average (314.90 tillers m2). As for the bilateral overlaps, the treatment of the interaction between the second seeds rate and the third nitrogen level was consistent in the characteristic of the crop growth rate from tillering to elongation, amounting to 48.46 g / m2 / week. Also, the third seeds rate and the second nitrogen level excelled in giving an average characteristic of the crop growth rate from elongation. To flowering, reaching 183.80 g/m2/week. As for the overlap between cultivars and nitrogen, the overlap treatment between the ACSAD cultivar and the second level of nitrogen was superior in giving the highest average of the two traits: the growth rate of the crop from elongation to flowering 182.10 and the relative growth rate from elongation to flowering 1.89. As for the three-way interactions, the interaction treatment between the cultivar IPA 265 and the second level and the quantity of the fifth seeds excelled in giving the highest average of the two characteristics: the growth rate of the crop from tillering to elongation 52.250 g / m2 / day and the relative growth rate from tillering to elongation 3.05 g / m2 / week. As for the overlap treatment between cultivar IPA 265 and the third level of nitrogen and the fifth seeds rate, it excelled in the characteristic of the number of tillers and gave the highest mean of 436.70 tillers m2.