Reduced Herbicide Inputs in Cereals

Abstract

The objective of this project was to examine if herbicides used in cereals at rates lower than recommended by the manufacturer (reduced rates) would give acceptable weed control resulting in lower crop production costs. Field trials with a number of herbicides at full and reduced rates were carried out in winter barley, winter wheat and spring barley in 1994-1996. Herbicides used at recommended rates gave the highest and most consistent levels of weed control. Herbicides used at 50% of the recommended rates gave slightly lower levels of weed control than the recommended rates but did not result in lower yields. While rates lower than 50% gave about 70% control of weeds, grain yield was reduced in some trials. Reduced rates gave higher weed control in barley than in wheat. The level of weed control was influenced by weed species and the growth stages of the weeds at the time of herbicide spraying. Thus selection of herbicides and their rates of application should be field specific. The findings show that it is possible to reduce the amount of herbicides used in cereals with considerable cost savings and reduced risk of herbicide residues in grain, soil and water.