On the methodology of recommendation for the application rate of chemical fertilizer nitrogen to crops

In the present paper the methodology of recommendation for the application rate of chemical fertilizer nitrogen(N) is discussed.Adaptation of the regional mean optimal application rate of chemical fertilizer N(RMOR) for the recommendation for rice and wheat crops is evaluated from the view point of yield efficiency,net income and environmental impacts based on the network of field experiments conducted in Tai Lake region in 19821985 and 20032004 years,respectively.It is suggested that the RMOR in combination with tuning according to the specific field conditions can be used for the recommendation.