N,P & K absorption and utilization in sugarcane under different substrates of fertilizer resources

In order to investigate the effect of vinasse (waste effluent from alcohol fermentation in sugarcane mill) on the growth of sugarcane plants, different rates of vinasse were applied as liquid fertilizer on sugarcane crops, under routine fertilization, vinasse fertilization and non fertilization. The results indicate that the emergence, young shoot growth and absorption of N, P K by young sugarcane plants are impeded by vinasse application, but this impedance is minimized through self-metabolism and finally vanishes at tillering stage. By mid-tillering stage, nitrogen, phosphorus and potassium contents in plant leaves are higher in vinasse treatment than in the control and routine fertilization treatment, indicating that the vinasse treatment accelerates tillering and elongation, thereby improving cane yield. Subsequently, yield under vinasse treatment equals that under routine fertilization treatment, suggesting that appropriate doses of vinasse could be used as liquid fertilizer for sugarcane cultivation. Based on performance of agronomic characteristics, optimal rate of treatment for sugarcane is 45 t·hm-2 vinasse+60 t·hm-2 water for planted crops and 105 t·hm-2 vinasse for ratoon crops.