I know when the word fertilizer is mentioned, we usually refer to NPK fertilizers.

我知道，说到肥料，我们通常指的是氮磷钾。

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In addition, the structure of ammoniator-granulator, and the operation condition for MAP, DAP and NPK fertilizers are explained.

同时阐述了转鼓氨化造粒机的构造以及用于生产MAP、DAP和NPK复合肥的条件。

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Results showed that long term application of NPK fertilizers or manure could increase soil biomass-N, especially the effect of manure on biomass-N was obvious.

结果表明，长期施用有机肥或化肥均能增加土壤生物量氮数量，尤以有机肥的作用明显。

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