Sediment, nutrient and herbicide runoff from cane farming practices in the Mackay Whitsunday region: a field-based rainfall simulation study of management practices

Level 1 General Description


The aim of this study was to assess the relative impact  varying application rates (nutrients and herbicides) on surface water quality on Controlled Traffic Farming (CTF) practices, from simulated and natural rainfall events.

Methods (Brief)

The study was undertaken on a sugarcane farm in North Eton, SW of Mackay. Flumes and automatic samplers were used to monitor sediment runoff for nutrients and herbicides on three different management practices using both artificial rain stimulation and natural rainfall events.

Key Findings (Brief)

Lower runoff was achieved on CTF treatments as they were less compacted compared to Current Practice (CP) treatments, therefore improving infiltration. Total sediment loads were reduced by 44% on CTF treatments compared to CP treatments.

Total nitrogen loads from surface applications of dunder (Liquid One Shot) and subsurface applications of granular (Nitra King S) fertiliser were similar, as both were applied at the same rate (160 kg N/ha). Granular applications had greater loads of nitrate at day 1 and day 21 than dunder, with losses being reduced on CTF treatments compared to CP treatments. However, dunder applications had greater amounts of ammonia, especially at day one, compared to granular treatments. This loss was greatest on CP treatments.

Avoiding dunder application within the onset of significant rainfall within at least three weeks will reduce the risk of ammonia loss in runoff by 44% on CP treatments and 29% on CTF treatments.

In summary, the recommended best practice for management of water quality in cane farming is no-till green harvested controlled traffic farming, with fertilisers and herbicides applied as early as possible before the onset of the wet season.


The study was carried out on a cane farming property in North Eton, SW of Mackay (21o 12’ 46’’S 148o 57’ 7’’E)

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