Source and variation of nitrogen along middle and down stream of Weihe River and its main tributaries

As the biggest tributary of the Yellow River,the Weihe River was confronting more and more serious effects from human being activities.The purpose was to explore the variety of NO-3-N and NH+4-N along the Weihe River and possible factors affecting them.It can be characterized by the results that the water pollution along the middle and down stream and its tributaries of Weihe River was mainly exceed by NH+4-N,part sampling sites were nearly close to the critical value of the safe drinking water standard.As to the NH+4-N,the middle stream and tributaries are supposed to put main attention in preventing spot-pollution,while the down stream needs to improved the management of environment,specially for the wastewater drainage.For NO-3-N,more attention should be paid to the nitrate management in the downstream of Baoji and Weinan.Rational and high efficiency of fertilize utilization should be widely spread in tributaries.