ONLY A quarter of farmers accept that 7.5% is the safe moisture content for long-term storage of oilseed rape, according to a Home Grown Cereals Authority (HGCA) survey.

While this is almost double the response of 10 years ago, farmers need to realise that at moisture levels above 7.5%, their crop is at risk, said the Central Science Laboratory’s David Armitage, who was involved with the research.

“At 7.5% moisture content (mc), few mites occur in the bulk. Although the surface mc may rise to about 11%, application of Diatomaceous Earth (DE) is effective in controlling mites in these circumstances.”

At 9% moisture, infestations occur throughout the bulk and DEs will not work, he warned. “Furthermore, rancidity occurs at the bulk surface which may take the free fatty acid above the market threshold of 2%.”

The survey also found that while the majority of growers calibrated the meter in the harvest year, less than half of those questioned calibrated meters properly by sending them to the manufacturer – yet accurate measurement is essential, he said.

Details of the survey can be found at www.hgca.com project reports 371 and 376.