Grain yield and forage characteristics of forage sorghum under different plant densities and nitrogen levels in second cropping after barley in Isfahan, Iran

In order to determine grain yield, forage yield and some forage physical characteristics in second cropping after barley, an experiment was conducted at Research Farm, Faculty of Agriculture, Islamic Azad University, Khorasgan Branch, Isfahan in 2009. In this study, completely randomized block design with four replications was used. The main plots were plant densities, namely, 250000, 300000, 350000 and 400000 plants per ha, and four levels of nitrogen, namely, 0, 80, 160 and 240 kg N/ha were sub-plots. The effects of plant density and nitrogen levels on number of seeds per panicle were not significant. The maximum number of seeds per panicle, 1000-seed weight and seed yield were related to application of 160 kg N/ha and 250000 plants per ha. But, the highest plant height, number of leaves per plant, LAI, fresh and dry forage yield were achieved in 400000 plants per ha with application of 240 kg N/ha. It seems that 400000 plants per ha with 240 kg N/ha were suitable for producing high amount of forage in second cropping after barley.