Simulating trash and nitrogen management effects on sugar cane yield/Simulacao do efeito do manejo da palha e do nitrogenio na produtividade da cana-de-acucar

The objective of the study was to model the growth and productivity of green and burnt sugarcane harvesting systems, under three nitrogen fertilizer levels (60, 120 and 180 kg [ha.sup.-1] ). APSIM-Sugar crop model was previoulsy calibrated based on two field experiments conducted in Piracicaba, SP and Salinas, MG, with the cultivar SP80- 1842. The sensitivity of the model was evaluated for the parameters of soil and variety, especially those related to the soil organic matter dynamics and nitrogen. The model simulated well the sugarcane growth and yield in the evaluated environments. Simulations showed that sugacarne yield being highly dependent on trash management. Trash removal from fields would ultimately decrease the crop yield. Simulations also revealed that the nitrogen doses as high as 180 kg ha-1 would not be enough to overcome the yield lost due to trash removal.