اثر فواصل آبياري و نحوه تقسيط كود ازت بر برخي صفات كمي و كيفي سورگوم علوفه اي

The effects of irrigation intervals and methods of N application on some quantitative & qualitative characteristics of forage sorghum

An experiment was conducted in 1994 in Karaj, Seed and Plant improvement Institute to study the effects of irrigation intervals and methods of N application on the yield and some qualitative and quantitative characteristics of forage sorghum (Sorghum bicolor (L) Moench var. speed feed). A split plot in time & site design with four replications was used; the irrigation intervals (every 7, 12, 17 and 22 days) were the main plots. Each main plot was sub-divided into three sub-plots for assigning the methods of N application. i. e. M, = 112 of N applied when the plants had 5 to 7 leaves and the other half after the first harvest. M2 = 113 of N at 5 to 7 leaves stage, 113 of N when the plants had 30 - 40 cm height and the last 113 of N after the first harvest. M3 = 113 of N at 5 to 7 leaves stage, 1 /3 of N after the first harvest and 113 of N when the height of regrown was about 30-40 cm. Results showed that 7 and 12 days intervals for imigation and M2, M3 methods of N application provided better conditions for crop development and growth, because the crop used environmental factors better than the other treatments. The most characteristics in M2 and M3 distribution of N were better than M,. It was concluded that, if the crop is sown in time, the 10 - 12 days of irrigation intervals and splitting nitrogen applications at two growth stages (M2 or M3) of sorghum is recommended for Karaj region.