Assessing soil moisture before applying residual herbicides is crucial to maximise product efficiency and reduce the risk of watercourse pollution, experts warn.

For optimum weed control in crops such as winter oilseed rape, soil moisture down to 8cm can be more important than crop or weed size when timing spray applications, said Dow AgroSciences’ Rene Pollak.

He advised growers to track weekly Met Office figures and check local field conditions to ensure soils are uniformly moist before using products like Kerb Flo (propyzamide).