Abstract
The effect of undersowing on a spring oat crop with four long-term ley mixtures was investigated. Ryegrass, cocksfoot, timothy and general-purpose mixtures were used; broad red and white clovers were included in all mixtures and two levels of nitrogen applied, no nitrogen (n0) and Nitro-Chalk at 3 cwt./acre.1. Panicle number was reduced by all the undersown mixtures except when cocksfoot was the only grass sown (mixture B).2. The weight of individual grains was slightly reduced by undersowing with a ryegrass-dominant general-purpose mixture (D) in the absence of Nitro-Chalk, and there was also an indication of a lowering of the total number of grains per panicle when Nitro-Chalk was applied.3. All the herbage mixtures reduced the percentage of kernel at both nitrogen levels under the ryegrass-dominant mixture (A), but only at one level of nitrogen when cocksfoot (mixture B) or timothy (mixture C) were the only grasses sown.