Abstract: Based on the measured data of crop water and nitrogen dynamic process during wheat and maize growth period at Luancheng Agro Ecosystem Experimental Station (CAS) in 2006-2007,authors validated the simulation capabilities of the CERES-Wheat and CERES-Maize models in crop water and nitrogen dynamic process in North China plain and analyzed their sensitivities of parameters.The results showed that correlation coefficients of soil water content,soil NO3〖KG-*2〗--N〖JP2〗 and plant nitrogen content simulated by model during crop growth period and their data were 0.46,0.74 and 0.68 respectively for winter wheat,and were 0.95,0.62 and 0.72 for summer maize.Furthermore,it was found that soil moisture and soil NO3〖KG-*2〗--N content were sensitive to the variations of soil parameters,but plant nitrogen content was influenced obviously by the genetic parameters.As the field moisture capacity increased 10%,the soil moisture increased 7.5% for winter wheat and 8.8% for summer maize,and soil NO3〖KG-*2〗--N increased 12.0% for winter wheat and 17.9% for summer maize.The effect of PHINT on plant nitrogen content of winter wheat was negative and it decreased 11.5% as PHINT increased 10%,and the effect of P1 on plant nitrogen content of summer maize was moresensitive and it increased 9.3% as P1 increased 10%.

Key words: Water and nitrogen dynamic, CERES model, Parameter sensitivity, Soil NO3〖KG-*2〗--N, Plant nitrogen content