The Potential Value of Different Nurse Crops for Organic Systems and their Influence on the Undersown Swards

R.F. Weller, P.J. Bowling and J. Valentine
IGER , Trawsgoed Research Farm, Aberystwyth, Ceredigion, SY23 4LL, UK

Abstract
The value of a range of spring-sown cereals and forage peas as nurse crops in organic systems was assessed in relation to forage production and their influence on the establishment and yield of undersown ryegrass/red clover swards.

Silage DM yields of over 9 t/ha were obtained from two husked oats and the naked oat cv. Bullion. Yield of the UK spring barleys cvs. Riviera and Dandy were 0.7-0.8 t/ha lower, and yields of 8.6 and 8.8 t/ha were obtained from the triticale cv. Purdy and the forage pea cv. Canis.

Grain, which is the most nutritious fraction, constituted a greater proportion of yield in barley than in the other cereal species. There was a clear inverse relationship between silage yield and aftermath growth.

The highest yields of the undersown swards were recorded when barley was the nurse crop, and the lowest when oats and triticale were used. This was attributed to the latter crops being later maturing and taller growing, thus reducing light penetration to the undersown sward.

However, there was little difference between nurse cereal crops in their clover content in the following spring, with a tendency for the swards undersown to oats and triticale to have fewer broad-leaved weeds than those undersown to barley. The swards undersown to peas had low clover content and higher weed levels.

 

 

Source
"Organic Farming: Science and Practice for Profitable Livestock and Cropping"
Proceedings of Symposium No. 37, British Grassland Society, 2004
Association of Applied Biologist & Colloquium of Organic Researchers

en français

Posted October 2007