Dynamic simulation of organic nitrogen mineralization in yellow soil of planting tobacco

Soil organic nitrogen mineralization dynamics were studied under different temperatures and soil water contents in order to provide the basis of forecasting soil nitrogen mineralization in fields. Intermittent leaching aerobic incubation was adopted to develop dynamic simulation models of organic nitrogen mineralization in yellow soil under different incubations which include constant temperature at 20℃, constant temperature at 35℃ and fluctuating temperature (5, 10, 15, 20, 25, 30, 35, 30, 25 and 20℃), different temperatures, ranging from 5℃ to 40℃, and various soil water contents, ranging from air-dried soil water content to 53%. Soil nitrogen mineralization in field was used to validate the simulation. The results show the soil nitrogen mineralization dynamics under fluctuating temperature is significantly different from soil nitrogen mineralization under the constant temperature incubations, and the fluctuating temperature incubation can improve soil nitrogen mineralization. The simulated dynamics of cumulative nitrogen mineralization is best by using cumulative temperature as a variable. The soil nitrogen mineralization under different soil water contents is modeled preferably by applying an exponent model. Base on the cumulative temperature model and exponent model, a new model is developed by using cumulative temperature and soil water content as variables. The mineralization is also simulated well by using the field measured data. Therefore, the soil nitrogen mineralization in fields can be forecasted well by using daily temperature and soil moisture as the inputs.