Avoiding crop damage from residual herbicides

摘要

The herbicide label is the primary source of information on herbicide use and growers should read them thoroughly to check residual activity and cropping restrictions. This article by Katherine Holloway discusses how herbicides break down and gives extra information on specific herbicides. SOME herbicides can remain active in the soil for weeks, months or years. This can be an advantage as it ensures good long-term weed control. However, if the herbicide stays in the soil longer than intended it maydamage sensitive crop or pasture species sown in subsequent years. For example, chlorsulfuron is used in wheat and barley, but can remain active in the soil for several years and damage legumes and oilseeds. A real problem for growers is the difficulty in identifying herbicide residues before they cause a problem. Currently, we are limited to predicting carryover based on information provided on the product labels about soil type and climate. Herbicide residues are often too small to be detected by chemical analysis, or if the testing is possible it is too expensive to be part of routine farming.