The idea has proved effective in some rich-world grain silos, but Tanya Stathers, of Greenwich University in England, wanted to see if it would work in the smaller-scale and rather different conditions of storage found in the tropics.

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Economic conditions and the scale of such projects mean that only the very brave will invest now, he says.

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However, campaigner and marine biologist Dr Miles Hoskin said that the trial "won't represent the conditions of the full-scale dredge".

BBC: Falmouth dredging trial 'won't show full-scale impact'