这是由于没有工业生产的化学物质的帮助，有机农场里的作物必须更努力的生长以保护自身。因此它们成熟后不会更有营养。
The idea is that, without help from industrial chemicals, plants on organic farms need to work harder to protect themselves. They end up becoming more nutritious as a result.
农民们使用这些物质来帮助作物生长，以及保护他们免受虫害和其它威胁。
Farmers use these substances to help crops grow, and to protect them from insects and other threats.
在冬季生长的农作物由于北方的气候只能收到一点点的UVB招生，并且温室中的植物还受到了玻璃墙进一步的保护。
Crops grown in the winter in northern climes receive very little UVB to begin with, and plants in greenhouses are further shielded from UVB by the glass walls.
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