Get out into the field to assess nitrogen needs

Growers are urged to get out and assess the nitrogen demand of their backward crops following one of the wettest winters on record.

Many soils are showing lower levels of nitrogen than normal this spring and backward crops are in need of a growth boost from nitrogen fertilisers.

“We would encourage growers to get out into their crops and assess the nitrogen needs with a ‘little and often’ approach the most favoured,” says soil scientist Lizzie Sagoo at crop consultant ADAS.

Thin and backward crops would justify some early nitrogen when ground conditions are suitable, and she suggests 40kg/ha for winter sown cereals and up to 100 kg/ha for winter oilseed rape.

She says recent weather means most soils are generally wet and cold, and there has been no significant crop growth since November.

All arable areas will end up having an average or wetter than average winter, and nitrogen levels in soils are likely to be lower than average in the early spring season, she adds.

This means most crops are in average or poor conditions with few advanced crops that are well tillered or have a good canopy cover.

She adds all areas fall into the moderate or high excess winter rainfall categories this season so this should be taken into account when assessing a crop’s nutritional needs from DEFRA’s RB209 Fertiliser Manual.

Dr Sagoo suggests field inspection of crops will be essential to judge the need for early nitrogen, with those likely to benefit most being thin or backward crops, second cereals where take-all risk is high or where grain is intended for biofuels and starch, not protein, is wanted.

She warns that early nitrogen applications should not be made until soils have dried out and warmed up a bit.

Dr Sagoo says growers should not be applying nitrogen to waterlogged, frozen or snow-covered ground as this is financially wasteful as it can result in surface runoff and nitrogen losses.

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