广播电视英语短句 第 320 课：肥料使用-2

But the Chinese farmers used six times more nitrogen, and produced almost twenty-three times more surplus nitrogen. 但是中国农民施用的氮素比美国多六倍，产生的过剩氮则多23倍。

Government policies can have an influence. 政府政策有一定的影响。

For example, as China sought food security, its policies increased fertilizer use. 例如，由于中国寻求粮食安全，其政策增加了肥料施用量。

The researchers note that farmers in the Midwest used too much fertilizer on their crops through the nineteen seventies. 研究人员指出，20世纪70年代，美国农民为作物施肥过多。

But improved farming methods later increased their yields and, at the same time, made better use of chemical nitrogen fertilizer. 但是后来，改良的耕种方法增加了产量，同时，也更好地利用了含氮化肥。