Effect of irrigation intervals on vegetative growth and grain yield of grass pea and hairy vetch

In order to evaluate the effect of irrigation interval on vegetative growth and seed yield of grass pea and hairy vetch, a field study was conducted as split plot with randomized complete blocks design and four replication in research farm of Vali –e– Asr University of Rafsanjan. Main plots were irrigation levels including 40, 60, 80 and 100 mm evaporation from evaporation pan class A and sub plot were crop species in two levels as grass pea and hairy vetch. Result showed that 66 days after sowing (two weeks before flowering) leaf relative water content (RWC) of grass pea and hairy vetch significantly reduced by increased irrigation regime from 40 mm, however there were no significant differences between 60, 80 and 100 mm. Also, plant leaf area and biomass of both crops were reduced by increased irrigation regime. While grass pea had higher leaf area than hairy vetch, both crops had similar biomass. Finally, yield and yield components of both crops decreased by irrigation interval, although grass pea had always higher yield components and seemed to be more drought tolerant. Results suggested that both crops well tolerated increased irrigation interval and were suitable for forage production if harvested at flowering, however, grass pea was better for grain production.