A new online tool to help propyzamide users get more out of the key herbicide by monitoring soil temperature and moisture data in their region has been launched by AHDB.

The herbicide is popular among growers of winter oilseed rape and winter beans to control blackgrass and other grass and broad-leaved weeds.

However, it will only be fully effective when there is adequate soil moisture and soil temperatures have dropped to 10C and are forecast to stay below that level.

See also: Growers advised to swap herbicides to tackle broad-leaved weed resistance

“When applied to warm soils, propyzamide breaks down relatively quickly and concentration in the root zone can reduce to the point where it can no longer kill blackgrass,” explained Paul Gosling, crop protection scientist with the AHDB.

Sufficient soil moisture is also important in order to allow the chemical to move in the top few centimetres of soil, he added.

Data is collected from weather stations based at 30 AHDB Recommended List trial sites across England, Scotland, and Wales.

Weather data

Average weekly soil temperatures, recorded at a depth of 15cm, and soil moisture information, recorded at a depth of 10cm, are then displayed for each station on the website.

Data for the previous eight weeks is displayed so that growers can view which way the temperature and moisture are trending in their area.

“The trends displayed can help focus in-field monitoring efforts to decide whether fields are warming up or cooling down, and wetting up or drying out,” explained Dr Gosling.

Growers interested in using the tool can find it on the AHDB website.