Factors Affecting the Economics of Trashing

The trashing versus burning debate has been raging for many years, where trashing is defined as the physical separation of leaf material from the cane ‘stick’ prior to transporting the cane stick to the mill. This paper steers away from the environmental debate and focuses on the economics of trashing versus burning. Trashed cane can generally be supplied quicker than burnt cane, reducing sucrose deterioration and improving cane quality. A reasonable trash blanket left in the field after trashing inhibits weeds, thereby reducing herbicide costs. The additional organic matter above and below the soil surface improves moisture retention and soil health, which can significantly improve cane yields and profits. Trashing, however, is not appropriate in wet, low lying and cooler areas because the trash blanket increases the risk of stools rotting and inhibits ratooning respectively. The volume of trashed cane is also higher than burnt cane, which increases transport costs. In addition, extra trash delivered to the mill may necessitate upgrading the mill’s processing facilities. In November 2002, a multi-disciplinary working group was set up to compile an appropriate spreadsheet model. The results to date support a priori expectations that, although trashing should be promoted under certain conditions in the South African sugar industry, further research is required in the following areas: (i) yield benefits of trashing under different circumstances, (ii) cane composition of different varieties, (iii) rates of cane deterioration, (iv) influence of density on transport costs, (v) labour productivity under different trashing regimes, (vi) the costs associated with alleviating bottlenecks at the sugar mills should trashing be widely adopted, (vii) the temperature effect in higher altitude areas, and (viii) the economics of trashed cane under irrigation. Introduction The trashing versus burning debate has been raging for many years, where trashing is defined as the physical separation of leaf material from the cane ‘stick’ prior to transporting the cane stick to the mill. Some environmentalists claim that removing the leaf material by burning impacts negatively on air quality. Obviously smoke and ash are a concern, but the beneficial impact of oxygen production through photosynthesis during the growing season is expected to result in a net benefit. The sometimes emotive environmental lobby has pressurised many industries and some governments to institute policies that ban or regulate cane burning, forcing growers to trash (Richard, 2002). This paper steers away from the environmental debate and focuses on the economics of trashing versus burning. Trashed cane can generally be supplied faster than burnt cane, reducing sucrose deterioration and improving cane quality (Wood et al., 1972). Growers can move from one field to another in response to weather patterns and other factors without much preparation. Therefore, scheduling is also easier and there are no nuisance complaints from the public concerning smoke and ash. A reasonable trash blanket (or mulch layer) left in the field after trashing