Effect of urea placement on crop cycle yield of green trash blanketed sugarcane ratoons

A trial was established in the Cairns region to examine the effect on cane and sugar yields over a crop cycle of various methods of applying urea to rainfed crops grown under green trash blankets. Ratoon crops grown over four years of varying environmental conditions were assessed. Results from individual years showed that applying urea to the trash surface soon after harvest always produced significantly lower cane yields than burying urea beside the stool. Combined results over the four years of the trial showed that burying urea beside the stool was superior to delayed surface application which, in turn, produced more cane than surface application soon after harvest. Although the capital cost of equipment to bury urea through trash blankets is high, yield benefits make it an economic proposition. Alternatively, growers could use a contractor to apply fertiliser to ratoon crops.