Wheeler said that scientists have not yet studied the yam's nutritional value to see what benefits the plant offers as a food crop.

怀勒说，科学家尚未对这种山药的营养成分及食用益处进行研究。

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As rice is the most important food crop in the world and maize is the main form of animal feed, these decisions could have a big impact.

由于水稻是世界上最重要粮食作物，而玉米是动物的主要食物，这些决定可能有重大影响。

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As a food crop, corn is also far more damaging to the environment than other crops, such as soybeans, because it USES more pesticides and fertiliser.

作为一种粮食作物，玉米比大豆等其他作物对环境影响更大，因为它需要更多的肥料和杀虫剂。

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Economists blamed the crisis on different causes, including high energy costs, bad weather and the use of food-crop lands for biofuel production.

VOA: special.2010.03.23

The method might be the key to the widescale production of fuel from algae, which is thought to be the better option over making it from land-based crops such as soya and corn, since the yields are much greater and there is no competition with food-crop production, and provide a real alternative to a globalized world that is utterly dependent on supplies of imported crude oil.

FORBES: 'Artificial Cells' May Provide Souce Of Algal Fuel

Seventy-five per cent of the food crop varieties we once grew have disappeared from our fields in the last 100 years.

FORBES: The Future of Life On Earth: Part Two Of The Discussion

Sudan is letting investors export 70% of the crop, even though it is the recipient of the largest food-aid operation in the world.

ECONOMIST: Buying farmland abroad