The number of cattle in Turkey increased from 10.5 to 14.0 million and similar increases were observed in sheep and goat population since 2001 to date (TUİK, 2016), therefore, increasing the need for the forage crops such as vetch which can easily be fitted to a double cropping farming. In 2016, Turkey produced about 4.5 million ton of vetch as animal feed which ranked third in the world (TUIK, 2016), therefore, is an important animal feed in the country. Herewith, a study was conducted to determine the effect of varying supplemental irrigation rates on Vetch (Vicia villosa L. cv. Selcuk 98) plant vegetative and generative characteristics under semi-arid climatic condition of Harran plain, Sanlıurfa, Turkey. A drip irrigation system with 4 l h−1 was utilized for irrigation treatments included 0, 25, 50, 75, 125% of full irrigation (100%) of which was scheduled based on soil moisture measurements. Full irrigated treatment received 294 and 263 mm in 2008 and 2009, respectively. In general, with elevated irrigation amounts vetch plants vegetative and generative characteristics resulted in statistical difference. Irrigation increased both number of branches and pod per plant values, however, 1000 seed weight values were not statistical affected showing the fact that plants vegetative growth did not lead to more rather less but similar size seeds. On the other hand, both seed yield and above soil biomass values were significantly (p < 0.05) increased with elevated irrigation amounts but analysis of data indicated no advantage of excessive irrigation.
