• Waterlogging this spring is causing hidden root damage that could reduce cereal and oilseed rape yields.
• Targeted foliar phosphate and micronutrients at T0 and T1 can help rebuild roots and protect yield potential.
• Trials show yield uplifts of 0.58t/ha in wheat and 0.3t/ha in oilseed rape, delivering up to a 3:1 return on investment.

After excellent establishment conditions, the recent wet and cold weather has left many winter crops sitting in waterlogged soils. As a result, root systems may now be suffering unseen damage that could compromise yields later in the season. However, according to Natalie Wood, agronomist and Product Manager for YaraVita & Biologicals, timely foliar nutrition programmes can help crops recover and safeguard yield potential.

"Strategic foliar applications at T0 – particularly of phosphate and key micronutrients – can rebuild damaged root systems and maintain crop sufficiency throughout the critical spring growth period," she says.

The hidden dangers of waterlogging

The problem lies in the anaerobic conditions created when soils are saturated. Starved of oxygen, the smaller roots begin to retract, leaving crops with only shallow primary roots. This creates a fundamental imbalance: the above-ground growth exceeds what the compromised root system can sustain, leading to tiller loss in cereals. "The longer crops sit in waterlogged conditions, the more damage is done," Natalie adds. 

Waterlogging also affects soil biology. "Microbes are starved of oxygen, so they're not able to mineralise the nitrogen from the organic matter," Natalie continues. This makes it difficult to assess how much nitrogen crops have been able to access over the winter period, adding another layer of uncertainty to spring nutrition planning. 

In addition, nutrient leaching in wet conditions can leave crops deficient just as demand increases.  

Why foliar nutrition works

Foliar applications offer a more efficient route for nutrients to reach the crop than soil-applied options, particularly in the current conditions. "Nutrients like phosphate can get into the crop very quickly through that leaf surface, aid root development and rebuild some of that damage done," explains Natalie.

However foliar applications need to work in conjunction with conventional fertiliser programmes, not as a replacement. "You would probably need to come back relatively soon with your solid application, because that amount of phosphate isn't enough to sustain the crop," Natalie explains. "It's enough to kickstart the growth, but it's not enough for that crop's demand."

Driving tiller retention and biomass in cereals

For cereals recovering from waterlogging, rapid early growth is critical. Protecting tiller numbers and rebuilding biomass will directly influence final yield. YaraVita CropBoost is recommended as a key product as it contains magnesium, phosphate, potassium and zinc. 

Applied at three litres per hectare at the T0 timing, or before, the foliar phosphate is a vital energy boost to help put on a lot of biomass in a short space of time. Phosphate will also promote root growth that could be particularly important later in the spring through potential dry conditions. "If the crop root system is compromised now and doesn't recover well in time, we could run into issues further on," warns Natalie.

When paired with YaraVita Gramitrel at the T1 timing, this combination has delivered impressive results. "On average, we've seen about 0.58 tonnes per hectare yield increase in wheat," Natalie notes. "You get some really good returns." This is a £99 benefit which is a 2.5:1 ROI if you want to add it in. 

Nutrition tailored for oilseed rape

For oilseed rape, Yara has developed YaraVita Brassitrel Pro, a crop-specific formulation containing magnesium, manganese, boron, calcium and molybdenum. According to research in Yara's Pocklington lab, these are the nutrients most frequently deficient in tissue samples.  

Applied at three litres per hectare in both spring and autumn, YaraVita Brassitrel Pro supports both vegetative growth and flowering. "The boron ensures flowering goes well," says Natalie. "It's basically trying to make the grower's life as easy as possible, getting all those nutrients into one can, one solution, saving them time and effort."

Application offers financial rewards too. Long-term trial results show yield increases of around 0.3 tonnes per hectare, representing approximately £116 per hectare based on current futures prices – equating to a return on investment of around three to one.

Building resilience through balanced nutrition

Beyond addressing potential or existing deficiencies, proper micronutrient nutrition builds crop resilience against stress pressures. "A healthy person tends to get less colds for example, and it would be the same for plants," Natalie explains. "If you've got a very healthy plant, it's going to be more resilient and better able to fight off some of those stresses."

This preventative approach aligns with modern nutrition thinking. "It's not just that we're covering a lot of bases, but we're also de-risking that crop," Natalie explains. "We're trying to make sure it's got everything it needs to grow, particularly when we're building the blocks for yield at this early stage."

Tank mix compatibility and digital support

A key benefit of YaraVita products is their compatibility with other agrochemicals. "A lot of work goes into that formulation," Natalie says. "From the raw material choice through to what surfactants and dispersants are in the mixture to make that top-quality product. But we also know it's got to mix with all the agrochemicals out there."

Extensive testing ensures YaraVita products are compatible with the most popular fungicides and herbicides used at key timings. For growers wanting to check specific mixtures, Yara offers its Tankmix service through the new YaraPlus platform. The service focuses on chemical compatibility – ensuring products won't turn to sludge or block sprayer filters and nozzles – and provides results within approximately two days.

"It's completely free of charge," Natalie emphasises. "You can use the tank mix app or go to YaraPlus, look up your mixture, and, if it's not there, request it." 

Plan now for T1

With key application windows approaching in early April for cereals at T1, growers should now be reviewing foliar nutrition strategies. 

Natalie's advice to growers is clear: "Be aware that waterlogging can cause unseen root damage. If crops are looking yellow, dig them up and assess the root system. Targeted foliar phosphate may help recovery. Using crop-specific formulations can simplify decisions and save time."

She also highlights the value of digital tools: "Use YaraPlus to improve nitrogen efficiency and make better-informed decisions. Even using variable rate maps alone can significantly improve nitrogen use efficiency."

And in the current economic and meteorological climate, that may prove particularly timely.