Effect of fertility management and variety choice on yield and baking quality of organic spring and winter wheat

摘要

Yield of wheat produced under organic standards has been repeatedly shown to be between 20 and 40% lower than those achieved in conventional farming systems and protein levels are also lower in organic wheat. This has mainly been linked to the inability to (a) control certain diseases (especially Septoria spp.) and (b) use foliar applications of mineral N-fertilisers later in the growing season. A large scale poly-factorial field trial carried out between 2003 and 2005 at Gilchester Farm investigatedthe effect of applying Rhizobium inoculants to clover seeds and compost amendments to clover swards grown prior to wheat crops on three winter-wheat and four spring wheat varieties from a range of European breeding programmes. Results showed that variety choice had the greatest effect on both winter and spring wheat yields, but that improvements to fertility management practices also significantly affects wheat yields and protein quality. For spring-spring wheat, the short-straw varieties Paragon and Monsun had lower yields than long-straw varieties (Zebra, Fasan) from European breeding programmes. Also, only longer straw winter and spring wheat varieties showed significantly increased yields when Rhizobium inocula and compost amendments to clover swards were introduced into the fertility management protocol. This clearly indicates that yields in organic wheat production can be significantly increased by improved variety choice and fertility management regimes.