07 April 2022
Timely reminder that drainage water may leach nitrate from fields
MOST UK areas received less precipitation over the 2021–22 excess winter rainfall (EWR) period, according to the Met Office, but this has not resulted in widespread changes in the EWR categories used to help determine soil nitrogen supply to crops.
EWR is the amount of rainfall the land receives after the soil profile becomes fully wetted in the autumn and before the end of drainage in the spring. EWR categories for most of the UK are the same as would be observed in an ‘average’ winter, with only some areas, mainly in England, entering the next driest category.
With fertiliser prices at historic highs, guides and calculation tools can determine the implications for nutrient management strategies. AHDB states that when soil is fully wetted, drainage water may leach nitrate from fields therefore growers should consider the extent of such losses in nutrient management plans.