广播电视英语短句 第 316 课：混植法-2

For example, some kinds of soil bacteria take nitrogen from the air and make a form that plants can use. 例如许多土壤细菌可以吸收空气中的氮并转化为作物可以吸收的氮。

The plants keep the nitrogen in their roots. 作物从根部吸收氮。

Legumes are especially good at this. 豆科植物尤其擅长此道。

Any crops sharing the same space can get the nitrogen as the roots decompose . 当豆科植物的根烂了以后，处在这些根周围的其它的作物就可以吸收氮了。

Crops like beans and potatoes can also share territory well because their roots reach different levels in the soil. 豆和西红柿也能混植因为他们的根处于土壤的不同的深度。