"Section 2.1: Cereals"Sustainable Weed Control in Small Grain Cereals (Wheat/Barley)

Abstract

Wheat, barley, oats, rye and triticale are important food and feed crops. Chemical weed control has become increasingly challenging through loss of herbicide actives, regulations and the diminished efficacy of active ingredients due to the evolution of herbicide resistance in weeds. In this chapter, the characteristics of some important weeds of cereal crops are described and more rational methods of weed control based on an understanding of weed biology are evaluated. Non-chemical methods are not silver bullets and it is a mistake to expect them ever achieve the levels of efficacy demanded by intensive large-scale farming systems. It is therefore clear that an integration and stacking of such methods is needed and even then, the efficacy may be insufficient. Longer-term approaches must therefore be included and these are not rocket science! The long-standing practice of crop rotation allows weed life cycles to be targeted in different ways in different crops, and growing a more competitive cereal species and/or switching from winter to spring cropping may be required. Integrating these methods with the use of herbicides is suggested as one way of preserving the chemical portfolio still available and making the evolution of herbicide resistance less likely. At the same time, financial concerns of farmers and the environmental concerns of policy makers and the public at large, need to be addressed and the use of more precise approaches and spatially-variable weed management is advocated for both organic and conventional farmers.