An early dose of nitrogen to nurse backwards cereal crops into action will be key to optimising yield after crops battled intense rainfall this winter.

Soils could be carrying 40-60kg/ha less nitrogen than usual as a result of persistent rain leaching N through the soil profile.

Winter wheat growers are advised to apply 30-40kg N/ha early doors in February, as soon as conditions allow, to promote leaf growth, encourage tillering and stimulate root development.

Targeting crop nutrition to field requirements will be essential to optimise returns, while questions loom over the viability of poorly established crops carrying high grassweed burdens.

See also: Video: Three growers reveal impact of rain and plans for the spring

Little and often nitrogen

ProCam’s technical manager for the South, Paul Gruber, says growers should be reluctant to go “too hard, too soon” with nitrogen in case the weather turns wet again.

“Applying 30-40kg N/ha in February is enough to kick-start crops. Remember, the earlier you start applications, the more little and often you want to apply it,” he says.

However, if growers find they are not getting on the land until March, he recommends upping N rates to 60kg N/ha to fuel the hungry crops.

For winter barley, a heavier rate of 80kg N/ha is recommended, although he notes that up to half of total nitrogen can be applied in the first hit.

Incorporating sulphur into early N applications is essential for maximising efficacy.

Persist or write off crops?

Some crops have been knocked hard by waterlogging, which has left farmers questioning whether to persist with suboptimal plant counts.

“There are some difficult decisions to be made, but realistically, if crops are poorly established and full of blackgrass it is feasible to write them off,” says Paul.

But don’t be too hasty with these decisions.

“Identify the stage of grassweed development. If blackgrass weeds are smaller than the two- to three-leaf stage, residual chemistry options will still have a reasonable effect, so it is worth persisting with,” he says.

What’s more, winter wheat can compensate well from waterlogging as it has the ability to put on yield later in the season, assuming growers can get on early with nitrogen.

“For a minimum wheat plant population you’re looking at 80-100 plants/sq m, whereas for hybrid barley you can persevere with a population of 100 plants/sq m,” he says.

Consider herbicide cut-off dates when opting for a late herbicide spray. It may also be worth testing seed as herbicide resistance pressures build.

Targeting N for best return

Tailoring N requirements to what is in the field will be vital.

“Clearly, there is no point chucking money at bare ground,” says Paul, who suggests using variable-rate applications based on satellite imagery and green area index to target nitrogen investments.

Taking a soil mineral nitrogen test to verify how much N is available in the soil may also be beneficial, or growers could simply work out of the RB209, assuming a high overwinter rainfall category.

“Nitrogen remains one of the best inputs for return on crop yield. For potentially high-yielding crops we don’t want to restrict yield by overestimating how much residual nitrogen we have kicking about in the soil,” says Paul.

Disease, aphids and frost lift

Despite the doom and gloom, there are some well-developed crops out there. Following the relatively mild winter, the threat of disease could be considerable – particularly septoria in the South and West of England.

“We’ve had a few frosts to date but nothing terribly cold. If it continues to stay mild there will be a lot of disease carryover into the spring.

“Learning from last year, if this is the case again, we will need to hit crops hard with an early fungicide,” he says.

Similarly, barley yellow dwarf virus may be problematic as the mild winter promotes high populations of aphids, so keep an eye out for aphid alerts.

© Tim Scrivener

On the flip side, if we enter a prolonged cold spell, frost lift could be an issue. This is where waterlogged soils freeze and on expansion uproot small plants from the soil.

“In this scenario, a pass with the Cambridge rolls in the spring, when conditions allow, to physically reposition the soil back into place is an effective way to remedy crops that have been impacted,” says Paul.