How UK heatwave has turned cereal straw pink
© Proterra This summer’s hot and dry weather conditions have resulted in the occurrence of pink straw in some cereal crops, a phenomenon last widely observed during the dry summer of 2022.
“Pink straw appear when stress hormones accumulate in plant matter and is associated with challenging growing conditions, particularly high heat and drought,” says Agrii seed technical manager John Miles.
The pink or reddish colour is associated with the production of anthocyanins, which are produced as a natural plant defence mechanism.
While the pink colour itself is not caused by potassium deficiency or excess, there are potential implications for potassium off-take and future management.
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In dry summers, potash off-takes can be higher due to a greater proportion of the nutrient remaining in the straw after harvest, rather than being washed into the soil.
Potassium is locked in the plant matter as the crop senesces early and the nutrient is unable return to the soil, as low water availability shuts down the process of osmosis.
“It does result in higher-than-average potassium contents in the straw, which in turn depletes soil potassium, so it’s important to monitor indices and make sure they are maintained,” says John.
