Nitrogen fertilisation for trash conservation farming at Mackay

Cane growers obtain large responses in sugar production from the use of nitrogen fertilisers (Chapman, 1982). Application rates currently average 185 kg N/ha, compared with a rate of over 200 kg N/ha in the early 1980s (Chapman and Greenwood, 1988). The value of nitrogen fertiliser applied each year to the sugarcane crop in Queensland is in excess of $50M. This is a major cost of cane production and the efficient use of nitrogen fertilisers is therefore of major concern to canegrowers. There is a continuing trend for cane growers to adopt green cane harvesting, but this is not as advanced in the Mackay area as it is in north Queensland. Growers at Mackay and elsewhere are concerned about fertilising strategies when a trash management system is adopted, and seek answers. This paper presents data from three rates of nitrogen trials conducted in fields with green cane trash blankets (GCTB).