Grain growers embarking on sowing this year’s winter crops are advised to factor the soil persistence of herbicides into their programs.
Independent Consultants Australia Network's weed specialist Mark Congreve said it was important to understand the soil persistence of a herbicide and its potential impact on following crops in the rotation, prior to the herbicide's use.
“Herbicides designed for residual weed control need to provide weeks or months of persistence in the soil to achieve their desired weed control objectives,” Mr Congreve said.
“As well, some herbicides that typically are used for post-emergent weed control and which are not typically considered ‘residual’ herbicides may also persist in the soil for some time after application.”
To provide grain growers and advisers with relevant information to assist in planning the use of herbicides in crop sequences and in managing rotation constraints, the Grains Research and Development Corporation has produced a national reference manual, Rotational Crop Constraints For Herbicides Used In Australian Farming Systems.
The manual is divided into two parts. The first part covers the principles of herbicide persistence in the soil and the factors that influence herbicide breakdown. Part two of the manual is a summary of label statements relating to directions for managing rotational crops.
The manual contains a series of frequently asked questions and links to other useful resources.
The manual can be found at: https://grdc.com.au/rotational-crop-constraints-for-herbicides