Evaluation of green-cane harvesting and crop management with a trash-blanket

Abstract

To evaluate the feasibility of green-cane harvest at San Carlos Sugar Mill in Ecuador, the agronomic parameters that may be affected when changing from burned to green-cane harvest were evaluated. Two sites were harvested green by hand and compared with two adjacent sites that were also harvested manually but burned. Manual, green-cane harvesting was found to be not feasible for San Carlos Mill due to the prohibitive increase in harvesting cost caused by the reduction in productivity of 68% of the field labourers. Subsequently, an experiment was undertaken with mechanical harvesters, comparing six sites that were cut green and another six adjacent sites that were burned before harvest. In mechanical greencane harvest, the machine productivity was reduced by 43% and the trash content in the delivered cane was higher by 38%. Several advantages of the green-cane harvest were, however, found. The mass of crop residues that remained in the field after mechanical harvest was significantly larger under green harvesting (17.31 t/ha) when compared to the burned treatment (3.7 t/ha). The contents of P and K in the residues were the same, but N content in the green harvest residues (0.85%) was significantly higher than in the burned residues (0.55%). In addition, after green-cane harvest, the cost of weed control was reduced by 35% and of irrigation by 10%. While sucrose recovery was not affected, insufficient data were available to draw valid conclusions on cane yield. After considering the impact of all the parameters that were monitored, economic analysis currently favours burned-cane harvest. Conversely, we believe that if better trash-extraction was achieved and if the nutrient recycling of the trash blanket was quantified, the balance would tip in favour of green harvest. It is necessary to continue the evaluation of mechanical green-cane harvest to understand the conditions under which it is favourable and to assess its long-term effects on soil health and cane yield.