How to nurture wet-weather-ravaged cereals
Wednesday, 6 March 2024
AHDB’s Ollie Johnson blogs about nurturing cereal crops following a storm-filled autumn and winter.
A friend of mine, who works in the Middle East, boasted that it only rains twice a year in the Saudi Arabian city of Jeddah. I replied that we are neck and neck because it only rains twice a year in the UK too: all the way through the autumn, then (after a brief interlude to tempt some drills into action) all the way through the winter.
It’s fair to say that is has been wet, with some significant crop area losses at the back end of 2023. However, the planned patching up in January and February hasn’t happened for many because of the relentless weather.
The good news is that cereal crops that survive winter generally survive until harvest. Now, the question is how to nurture what has emerged and tillered, and retaining those tillers is particularly critical, with adequate nutrition key.
In very wet or waterlogged soils, root systems struggle to penetrate to a great depth. As a result, most of the nutrient- and water-gathering potential is concentrated close to the soil surface. With sufficient moisture, this may be fine, but drier conditions could cause a real issue.
This year, leachable nutrients, such as sulphate and nitrate, will need to be managed particularly closely. These may have been washed down the soil profile, beyond the reach of relatively shallow root systems. Early nutrient applications are likely to be critical to retain tillers.
Where root systems are compromised, it would be wise to consider foliar applications of sulphur at the T0 fungicide timing – not to be confused with sulphur-based ‘fungicidal’ products, which are applied for a different purpose at this timing.
Where rooting is reasonable, ammonium sulphate granular products, such as DoubleTop and AXAN, are also options. However, care is needed when using alternatives that require mineralisation (microbial breakdown into plant-available form) in soils to facilitate uptake, such as polysulphate and elemental sulphur products.
In waterlogged, anaerobic conditions, mineralisation is likely to be compromised, so plant uptake may be lower than expected. The same applies to soil residual nitrogen. A soil mineralisable-nitrogen test may be well worth the investment (normally about £50–£70 per field) to help determine the amount of crop-available nitrogen and help you adjust nutrient management plans.
For oilseed rape, stem extension is not far away. When flower buds are visible above the crop, it is the last opportunity to tackle key broadleaved weeds, such as mayweed, crane’s-bill, thistles and cleavers. Walk fields as soon as possible and prioritise areas for treatment before the window closes, especially as spray opportunities could be limited by the weather and travelling conditions.
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