The Assessment Method of Nitrate Nitrogen Leaching and Ammonia Volatilization of Winter Wheat-Summer Maize Rotation in North China Plain Based on RZWQM Model

Nitrogen loss through NO₃^--N leaching and NH₃ volatilization are the two major ways in North China Plain. Direct monitoring of the mentioned nitrogen loss in farmland conditions is complicated due to laborious and expensive research work. To overcome these difficulties, it is imperative to develop a practical model for the appropriate estimation of nitrogen loss through leaching and volatilization. The model should estimate the nitrogen losses through each channel rapidly and be convenient for the management department. The model's basic mechanism should ascertain scientific and accurate relationship between quantity of actual nitrogen losses and soil properties. For these purposes, the model RZWQM was investigated. The mentioned model was found to be validated for wheat-corn crop rotation long-term field experiment in North China Plain. Through regression analysis, the model established a function between quantity of nitrogen loss and the amount of residual NO₃^--N in 0-1 m soil profile layer. Research literature data regarding North China Plain validated the function relation accuracy of the model under investigated, which was observed 70.9% and 71.2%. So, it is suggested that the RZWQM model can be used practically by management department to estimate and control non-point source pollution in North China Plain.