Season effects on productivity of some commercial South African sugarcane cultivars, II: Trash production.

Abstract

The demand for sugarcane trash as a means of reducing fertiliser inputs by recycling nutrients and improving soil health could be challenged in future by the demand for lignocelluloses as a feedstock for ethanol production. Large quantities of trash may also have deleterious effects on crop growth, and ameliorative steps may be needed to avoid this. A study was therefore undertaken to quantify trash production by various commercial sugarcane varieties, in different seasons. Amounts of trash were measured in three well irrigated experiments which had a range of commercial cultivars and crop start dates as treatments. Potential trash yields ranged from 5.2 to 23.9 t/ha; lowest amounts were produced by CP66/1043 and N21, and highest amounts by N14 and NCo376. Annual trash production potential was affected by crop start/harvest date, with the lowest amounts of trash being produced in winter crops. Large quantities of nutrients (e.g. 146 kg N/ha, 15 kg P/ha and 287 kg K/ha) are contained in trash and could be recycled, but may not be available to the following crop in the short term.