Effect of Plant Density and Nitrogen Fertilization on Growth and Yield of Some Grain Sorghum Cultivars

Abstract

This investigation was carried out to study the effect of plant density and nitrogen fertilizer on growth, grain yield, yield components, protein content and N recovery in grains offour grain sorghum cultivars, in Assiut University Experimental Farm during two successive seasons, 2000 and 2001. Grains of such cultivars were sown on June, 27th and 25th in both seasons, respectively. These cultivars were Dorado, Shandaweel-2, Mina and Horus, while plant densities were 46,666, 70,000 and 140,000 plants/fed., these densities were obtained by sowing in hill spacing of30, 20 and 10 em respectively, leaving two plants/hill after thilli1ing. Nitrogen fertilizer rates were 80, 100 and 120 kg/fed. in the form of ammonium nitrate (33.5% N), these rates applied at two equal doses, where the first one was applied after thilli1ing and the other dose was applied before the following irrigation. The field experiment was designed in a randomized complete Block design with arrangement, split-split plot with 7 replicates with a plot area of 10.5 m2 where grain sorghum cultivars were arranged in the main plot, and plant density were distributed normally in the first plot, while nitrogen rates were allocated nonnally in the second plot.

Five plants were chosen at random from each plot at plant age of

30, 45, 60 and 75 days from sowing, and the following characters were recorded. The dry weight of leaves, leaf area, L.A.I., stalk dry weight/plant, and relative growth rate was measured.

On the other hand, at harvest 10 plants/plot were taken randomly to determine the following characters:

Plant height (em), number of internode/plant, length of internode (em), green leaves/plant, panicle length, width (em), and weight, seed index (gm), grain yield/plant, shelling %, protein percentage in grains and N recovery in grains (kg/fed.). Grain yield/fed. was calculated on the grain obtained from plots.