Plan propyzamide applications with the AHDB WeatherHub

Friday, 26 October 2018

The AHDB WeatherHub can now be used to help target propyzamide applications to winter oilseed rape.

The WeatherHub presents a wide range of weather-related data, gathered from above and below the ground by UK weather station networks.

The new SoilMonitor dashboard provides a quick route to access soil temperature, air temperature and rainfall information. Available for a range of sites across Britain, the dashboard can be used to help target propyzamide use.

Propyzamide is a key active ingredient for many black-grass control strategies. No resistance to the herbicide has been recorded and high levels of black-grass control can be achieved within winter oilseed rape.

Extensive trials, conducted over many autumns, show that propyzamide applications must be made when soil moisture is sufficient and soil temperatures have dropped to, and are forecast to stay under, 10 °C at depth to get the most out of the active ingredient. If applications are made when the soil is too warm, propyzamide will breakdown too quickly and black-grass control will be compromised

Once a relevant weather station site has been selected from the UK map in the dashboard, a series of charts reveal soil temperatures and the trend.

Paul Gosling, who manages weed research at AHDB, said: “Soil temperatures are taken at 10 cm depth. This is quite shallow, making them quite responsive to short-term changes in air temperature. However, by using the forecast air temperatures on the dashboard, it is possible to estimate whether soils are likely to stay below 10 °C."

Good levels of soil moisture are also needed to distribute the herbicide. Ideally, soil moisture deficits need to be less than 50 mm, although moisture conditions in the top 5 cm are particularly critical. Applications, however, should not be made to waterlogged/saturated soils or if heavy rainfall is forecast to avoid any risk of contamination to water. Importantly, all aspects of good stewardship should be applied.

The AHDB SoilMonitor dashboard can be used in conjunction with the weather data Kerb postcode checker offered by Dow Agrosciences.