IMPACT OF THE GREEN CANE HARVEST AND PRODUCTION SYSTEM ON THE AGRONOMY OF SUGARCANE

摘要

Economic, community, and environmental pressures are the major drivers for wider adoption of green-cane harvesting/production systems in most sugar industries. Agronomic implications of the green-cane trash blanket (GCTB) produced by residues from the harvesting of green cane are explored. Once implemented in suitable climatic and soil associations, the economic benefits of a GCTB system are enhanced by environmental and social benefits that include reduced: use of pre-emergent herbicides, tillage, and soil erosion and stream turbidity plus improved conservation of soil moisture, lower irrigation need, improved air quality and life style for farm managers and workers. Improvements in soil chemical, physical and biological fertility are associated with the recycling of carbon and nutrients in trash. Uncertainty about the economic benefits of the GCTB system is a constraint to adoption in areas with a current high reliance on manual harvest and in cool and wet environments where the trash layer retards development of ratoons and yield, either because of extension of the period of low soil temperature in winter, allelopathic effects or enhancement of waterlogging and denitrification effects. The sheer bulk of trash in high biomass environments can be a constraint to ratooning, cultural operations and furrow irrigation. The change in significance of weed species is an emerging issue across sugar industries, resulting in need to focus on post-emergent control of large seeded vine weeds. We conclude that agronomic, socio-economic and environmental benefits associated with the GCTB system render it a more sustainable system in most tropical environments, but harvest and agronomic systems for implementation are not fully developed in some high biomass situations and in cooler and wetter sub-tropical environments.