In order to study the yield and forage quality of intercropping barley (Hordeum vulgare) and mustard (Sinapis alba) in different planting dates, a factorial experiment based on randomized completely block design with three replications was carried out at Farm Research Station, Gonbad -e- Qabus University. Factors were included as three planting dates (15 November, 6 and 20 December 2006) and four intercropping patterns (sole barley, 33.3% and 66.7% mustard instead of barley in replacement series, sole mustard). Delaying in planting decreased forage dry matter, plant height and protein yield, while protein percentage increased. Percentage of digestible dry matter, in soluble in acid fibers, water soluble carbohydrates and ash were not affected by planting date. The maximum forage dry matter, in soluble acid fibers percentage, protein yield and plant height. Sole cropping of mustard belonged to dry matter digestibility, protein and ash percentage belonged to sole barley. Land equivalent ratio in 66.7% and 33.3% mustard instead of barley were as 0.95 and 1, respectively. High yield of mustard comparing to barley increased intercropped treatments yield while intercropped treatments yield was lower than mustard sole cropping. generally, despite of lower protein content and digestible dry matter (as important forage quality criteria) mustard sole cropping was superior than others treatments, resulted from higher forage and protein yield.
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