To evaluate the impact of trash management on sugarcane production and N fertiliser requirements in environmental conditions of Brazilian coastal tablelands, a simulation was conducted with APSIM-Sugar cropping systems model. The model was parameterised for, and validated against results from a long term (over 23 years) experiment comparing the system-burnt trash and green cane trash blanketing (GCTB), in Linhares-ES. Simulations were conducted over two crop cycles (14 years) with different management (100%, 75%, 50%, 25% GCTB and burnt trash), and N fertiliser rates from 0 to 240 kg ha−1 (in 40 kg ha−1 increments) on the ratoon crops, and 75% of these rates on the plant crops. Measured cane yields and soil carbon were simulated well by the model. The RMSE (root mean square error) of predictions in burnt and GCTB treatments were 14.02 Mg ha−1 and 13.45 Mg ha−1 for yield, and 0.09 and 0.13% for soil carbon. In the simulation, the cane yield responded positively to the GCTB systems. Optimum N rates were higher in the 100%, 75% and 50% GCTB than with burnt trash and 25% GCTB reflecting the greater yields under GCTB systems. The response to trash retention was dependent on N fertiliser, and it was smaller or even negative at lower N rates. With adequate N, the positive responses were predicted to occur in all crops after the imposition of GCTB system. The removal of any proportion of the trash reduced the potential sugarcane yield. The simulations showed that average environmental losses of N are likely to be greater from trash-retained systems at all N fertiliser rates.