"The smugglers were trying to pick these up before daylight, but there was probably an agent in the area, " Adame said, explaining why the smugglers on the U.S. side never collected the canisters that pockmarked the tilled land.

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Biofuels Watch, a British lobby group, worries that a craze for the stuff could see virgin land tilled specifically to grow crops such as switchgrass, whose only purpose was to be pyrolised and buried.

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People usually till the land their parents tilled.

ECONOMIST: No title