effect of irrigation intervals on the yield and morphological characteristics of forage millet, sorghum and corn

crop production in arid and semi arid environments has been affected by drought stress. forage production have important role on animal production in this area. in order to determine the effect of irrigation intervals on the yield and morphological characteristics of forage millet, sorghum and corn, an experiment was conducted in a split plot with a randomized complete block design with four replications. the main plots include irrigation intervals (one week (i1), two weeks (i2), three weeks (i3) and four weeks (i4)) and the subplots include three different forage species: millet (m), sorghum (s) and corn (c). dry matter, plant height, stem diameter, number of nodes, number of tillers per plant, leaf yield, stem yield, sheath yield, inflorescence yield and leaf/stem ratio were recorded. the results showed that there were significant differences between irrigation intervals for number of tillers per plant and leaf/stem ratio at the first harvest. in addition significant differences were observed between different forage species on all studied traits at the first harvest. irrigation intervals and different forage species had significant effect on all traits at the second harvest. the highest and the lowest total dry matter yields (17.24 vs.3.41 ton/ha) in corn were obtained at one and four weeks irrigation intervals, respectively.