Plant density and Nitrogen Effects on Quality and Quantity traits of Forage Sorghum

摘要

A field experiment was carried out to investigate the efficacy of various plant densities and nitrogen applications on quantitative and qualitative traits of forage sorghum as factorial set of treatments based on randomized complete block design with three replications in 2010. Two factors included plant density at levels of 15, 20, 25 and 30 plants/m2 and nitrogen application at levels of full dose of nitrogen without split at sowing date, nitrogen application at two equal splits of 1/2 at planting time+1/2 at the first cutting and nitrogen application at three equal splits of 1/3 at planting time + 1/3 at the tillering stage + 1/3 at the first cutting. The recommended dose of nitrogen (full dose) was 100kg.ha-1. The tillers per plant were decreased as plant density increased, so between two cuttings, maximum tillers per plant were obtained in the second cutting with density of 15 plants/m2. The highest fresh forage weight and percentage of crude protein (CP) in the whole of cuttings, were achieved at the density of 15 plants/m2, nitrogen application in full dose without split for the first cutting. Also the first cutting had more dry forage weight than the second cutting. The lowest percentage of neutral detergent fiber (NDF) in the whole of cuttings was related to the density of 20 plants/m2 in the first cutting and nitrogen application in three splits.