Studies show farmland in Africa is often lacking in important nutrients. But researchers say a combination of farming methods may help. Since the world food crisis several years ago, researchers have directed more of their attention to small farms. 研究显示非洲的农田通常缺少重要养分,但研究者称一种联合农业方法可以起到作用.自从7年前发生粮食危机以来,研究者更多地关注小型农场.
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