Nitrogen is one of three fertilizers, but a great deal use of nitrogenous fertilizer has made environmental pollution, as soon as made the descend of nitrogen efficiency of corps and enhance the cost.

• 氮肥是作物的三大肥料之一，但是目前氮肥的大量施用不仅造成了环境的污染，同时导致作物对氮肥的利用效率下降，使农民的生产成本升高；