A BURNING ISSUE

Who doesn’t love a good cane fire? Many visitors to our district are keen to witness a burn and farmers often receive phone calls asking if /when there is going to be a cane fire. While a cane fire is a magnificent sight to behold, they generate an incredible amount of heat. Caution is important for both farmer and onlooker alike.
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To burn or not to burn?

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Initially, most of the sugarcane crop was cut green, with residual trash (green leaf matter) burnt on the ground. Burning prior to harvest was allowed in some mill areas where there was a high infestation of rats to reduce the exposure of hand cane cutters to leptospirosis (Weil’s disease), a potentially fatal disease spread by rat urine. But, after mass industrial action in August 1935 when 2000 sugar cane cutters and mill hands in North Queensland went on strike for nine weeks, burning became commonplace.
Labour shortages during World War Two led to widespread use of pre-harvest burning to speed up harvesting. Rising post-war labour costs saw burning become a standard practice to increase the output of manual (hand) cutters. This left only the stalks and tops thereby reducing the leaf matter, making it easier to cut by hand and to load the cane. Early mechanical harvesters in the 1960s were designed for the burnt system and were not well adapted to harvesting green. Burning persisted as standard practice until 1976 when a very wet season delayed harvesting operations in North Qld. This prompted growers to experiment more with mechanically harvesting green cane to avoid deterioration of burnt cane where it can be condemned if left too long in the paddock (5-7 days in our district depending on conditions). This deterioration of sucrose or CCS (Commercial Cane Sugar) reduces the commercial value of the cane making the milling process unprofitable. In Proserpine, this remains a significant consideration due to highly unpredictable weather patterns.
Soil is another factor resulting in the decision to burn or not. Some soils are difficult to manage if the cane is not burnt. If cane is harvested green and then it rains, heavy soil can become sour or waterlogged as the residual trash holds in the moisture. The wind and sunlight can’t penetrate the trash to dry the soil out. For the same reason, a farmer may also choose to burn paddocks that are low and/or not well-drained. Increased moisture retention can result in yield loss or poor regrowth of cane (ratooning). Farmers who plan to plough out and replant the same paddock immediately after harvesting will often burn the cane to get rid of the trash thus making replanting much easier.
Districts with high yielding crops, such as the Burdekin, have largely avoided green cane harvesting because of harvesting difficulties in high yielding, lodged crops. A substantial amount of water applied when irrigating also somewhat negates the benefits of retaining a trash blanket for moisture retention in this area.
Resistance to the practice of burning cane has mounted over the years. The “Proserpine Guardian” (June 25 1998) reported that the region’s sugar industry was under siege with the increasing threat of court action due to excessive smoke and ash fallout (referred to as “black gold” by locals for obvious reasons) allegedly affecting people’s health. These days only 5-10% of the Proserpine crop is burnt. While the cost of harvesting green cane is greater than burnt cane, the subsequent soil health advantages and moisture retention benefits of green cane harvesting remain important for long-term sustainable sugarcane growing.
Having said all that, a “good burn” does eradicate lots of vermin! And there is no doubt that it IS spectacular!
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Story and photo courtesy of Proserpine Historical Museum and Brendon Nothard (Canegrowers Proserpine).

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