Early sowing and irrigation to increase barley yields and water use efficiency in Mediterranean conditions

In rainfed Mediterranean areas, early sowings which lead to early growth and maturity to escape terminal heat and drought usually give higher grain yield than late sowings in years when rains come early. We test the hypothesis that early sowing coupled with a small amount of irrigation to ensure earlier emergence increases grain yield significantly, while improving irrigation water productivity. Replicated field experiments were conducted for 4 years in the semi-arid central Bekaa Valley of Lebanon. Barley was sown early, and half of the plots were irrigated with 25–30 mm of water immediately after sowing (EI). Half of the plots also received irrigation around heading stage (LI). Besides yields, other agronomic data were collected throughout crop growth, and the supplemental irrigation water use efficiency (WUESI) was calculated. Our results confirm the hypothesis that in Mediterranean areas early sowing followed immediately with a small amount of irrigation increases barley grain yield significantly. Farmers in the region should seriously consider practicing this technique as it produces a higher WUESI than irrigation at the heading stage.

► In Mediterranean areas, early sowing by end of October followed immediately with 30 mm irrigation increase barley yields significantly (+70% grain and +51% straw) in this 4-year field study.
► Farmers in the region should seriously consider practicing the technique since it has a much higher irrigation water use efficiency (56.8 kg mm−1), which was more than three times higher than that of the normal practice by irrigating at the heading stage.