The effect of plant density and nitrogen fertilization on yield, yield components and grain protein of grain sorghum

To study the effect of plant density and different levels of nitrogen on yield and yield components of grain sorghum (var. Sepideh) an experiment was conducted as split plot based on completely randomized block design with three replications in 2009. Four levels of nitrogen (0, 80, 160 and 200 kg N/ha) were the subplots and the main plots were different densities (100,000, 180,000, 200,000 and 280,000 plants per ha). The results indicated that the effect of plant density on percentage of panicle fertilization, 1000 kernel weight, the number of seeds per panicle, biological yield and grain yield were significant, and the effect of nitrogen on grain yield, biological yield and percentage of panicle fertilization were significant. Also the interaction between nitrogen and density was significant on protein of grains. The treatment that included 200 kg N/ha produced the highest number of seeds per panicle, panicle fertilization, grain yield, biological yield, protein content and 1000 kernel weight. The highest number of grains per panicle, panicle fertilization, grain yield, 1000 kernel weight and protein content belonged to density of 100,000 plants per ha. Ultimately, plantation of this variety of grain sorghum with 100,000 plants per ha and 200 kg N/ha seems suitable.