Michael Waring
Region: Trebonne, north Queensland, 1.5 hours north of Townsville
Commodity: Sugar cane
Farming area: 133 hectares
Rainfall: 1.5–4 metres rainfall per year
Email: michael@terrain.org.au
Phone: 07 4777 1361, 0428 771 361
My philosophy is to be open-minded to anything, even if you don’t think it’ll work. Just because it’s different to what you’ve done, you can’t assume it’s not beneficial for your farm unless you try it.
See what Michael has to say about:
- Trials and tribulations of sugar cane farming in the wet tropics of Queensland
- Wet country plus highly variable rainfall equals flooding
- The tough calls—planting and harvesting decisions hinge on the weather
- Green cane harvesting and trash blanketing—beneficial practices now the norm
- 1.9-metre row spacing can save money and improve soil health
- Mapping the yield potential of zones in paddocks to increase fertiliser efficiency
- Being open to new practices and trialling ideas for your farm
Trials and tribulations of sugar cane farming in the wet tropics of Queensland
We farm sugar cane in the Herbert Valley, which is about 1.5 hours north of Townsville in Queensland.
My parents have been farming here since the mid-1950s and I took over in 2000. Before that I was a sugar cane–agronomist with Herbert Cane Productivity Services.
The Herbert River is the major river system in the district, and it forms a valley which floods regularly.
We have 133 hectares spread over 3 separate properties—over the years we’ve purchased more properties.
Of the 133 hectares, approximately 40 hectares are what we call wet country—it’s in a wetter part of the district, and it’s the type of country that stays wet longer. About 65 hectares are dry country, which has lighter soil, is better drained, and in a lower rainfall area. The remaining 28 hectares are the home farm, which is in a wet area but is free-draining, river-flats soil.
Sugar cane is a grass that we plant every 6 years or so. To establish the crop, we place a stalk of cane in the ground. After 12 months we harvest that cane and it grows back, like when you mow the lawn. That second growth is called ratoon cane.
After about 5 ratoons, we cultivate the paddock and leave it fallow for a year. 15% of our farm is fallow each year—either bare, or with cowpeas or soybeans on it as a cover crop and source of organic matter and nitrogen. After that year, we replant cane.
Wet country plus highly variable rainfall equals flooding
We don’t irrigate the farm because average annual rainfall is about 2.5 metres. In 2010, we had nearly 4 metres. A very dry year is about 1.5 metres.
The majority of our rainfall comes between January and April, with light rainfall in May/June/July.
August to December is our dry season. Some years we can go from August to December without any rain at all. Some years, such as in 2010, we had 1 metre of rain in that period. It was a major disaster for our industry because it interrupted harvesting and affected the growth of the cane.
However, the variability in rainfall can be huge. I think we have to learn to farm so that our systems suit the huge variability in our weather as much as they can.
Because about half of our land is wet country, it is affected often by flooding. This affects our harvesting (the ground won’t carry the machinery), the ratooning of the cane, the growth of the cane, and our ability to control weeds.
In the last wet season [2011] we had 5 small floods. The longest lasting flood in memory was in 2009 and some of our cane was under up to 5 metres of water for 9 to 10 days. I had to replant an extra 20 hectares and lost approximately 1500 tonnes of cane.
The tough calls—planting and harvesting decisions hinge on the weather
Our big ‘weather decisions’ are when to plant, when and where to harvest, and the timing of fertilising. Confidence in forecasts makes these decisions easier and I hope helps me make the best decision.
The forecasts I look at are the Southern Oscillation Index (SOI) on the Bureau of Meteorology site, and the forecast from the Herbert Cane Productivity Services. Because rainfall has been recorded at the sugar mill for about 120 years, they have a very good record of relating average (or median) rainfall to the SOI.
We get that forecast every 2 months, and it’s based on the Bureau of Meteorology’s SOI, but localised for the Herbert. It gives us a percentage chance of above- or below-median rainfall.
It takes about 5 months to mill our crop and turn it into sugar. Harvest machinery rotates around a local grower group. [Each farmer harvests a certain amount, then the next farmer does the same, until all the cane is harvested.]
If it’s looking like a wet year, we need to decide whether to cut the wet country areas as soon as they’re somewhat dry, leave them until they get a bit drier, or cut the dry areas when you could be cutting the wet areas… it’s complicated.
In 2010 we had a forecast for a wet year. I made the decision in June that as soon as I could cut our wet country, I would. That was a good decision, because from September on, it got wetter and wetter. This decision reduced the amount of cane I was unable to harvest.
But these decisions mean leaving some of your other areas vulnerable.
For instance, plant cane [the first growth after planting] and first ratoon [the re-growth of cane after its first harvest] is the cane you really want to cut at its prime. Younger ratoons are more productive, so that’s the cane you try to look after.
There is an advantage of having different soil types on our properties: early in the harvest we can often cut our drier farm first because it can carry the machinery and the cane is more mature. We can then get to the wetter country, later in the season, when it has had the chance to dry out.
Green cane harvesting and trash blanketing—beneficial practices now the norm
Green cane harvesting is now normal practice in the Herbert Valley—it’s very rare to see a cane fire in the Herbert these days. It’s been common practice for 20 years now. What brought it about was the innovations in technology and the improved ability of harvesters to cut green cane.
It took us about 2 years to go from fully burnt to about 95% green—we saw the benefits and changed.
Now our farm is entirely under a green cane ‘trash blanket’, which means we don’t burn any of the cane or any of the leaf matter from the cane. When we harvest, mulched-up leaf matter is blown back onto the ground.
All the ‘trash’ is left in the paddock and it forms a mulch on the ground. The benefits are that it conserves moisture in a dry year, controls weed growth (reducing our chemical needs and costs), and we’re putting organic matter back into the soil instead of burning it.
After a good crop, the trash blanket is quite thick, so after it rots, there’s a very high organic carbon level on the top of the soil.
We’re helping to maintain the organic carbon in our soils. Higher organic carbon in soil improves the nutrient-holding capacity and soil health enormously.
Unfortunately, after 5 years, when we cultivate the paddock it tends to destroy the organic carbon. So we are looking at options where we don’t need to cultivate the paddock—or if we do, with very minimal cultivation. That will save us money too: every time you hop in a tractor it’s costing you money.
1.9-metre row spacing can save money and improve soil health
90% of growers here plant at 1.5–1.6 metres between their rows. However, harvesters have a wheel track of 1.9 metres wide, so the wheels travel over where you’re growing cane twice each year. This compacts the soil, especially under wet conditions.
I have changed to a 1.9-metre row spacing (the width of the harvesting machinery) and use controlled traffic and autosteer. In that 1.9-metre space, we plant 2 rows of cane. The gap between the wheel tracks is 1.4 metres and that’s never driven on.
I also plant on a mound that is 6–8 inches high with a disc opener planter. The planter makes a very narrow ‘V’ in the ground and lays the billet [stalk] of cane, fertiliser and chemical in the soil. There’s no cultivation of the soil after that.
This method reduces waterlogging, compared to the conventional method of planting in a furrow 3–6 inches below ground level. By not disturbing the soil, we conserve moisture that we might need and reduce weed emergence.
We don’t plan on ever cultivating the whole paddock again. We will only cultivate the beds, or maybe very limited cultivation of those beds. It’s cheaper, and cultivation destroys your soil structure and releases carbon.
Mapping the yield potential of zones in paddocks to increase fertiliser efficiency
We are also trialling variable-rate nutrient application—varying the rate of applied nutrients depending on the yield potential of each area of each paddock.
We measure electrical conductivity in the soil with a Veris machine to establish zones in paddocks. We take soil samples in those different areas, look at yield and topography in those areas, and come up with a yield potential for that area.
If you have an area in a paddock with poor soil and regular waterlogging, it’s never going to grow 100 tonnes a hectare—its yield potential might only be 80 tonnes a hectare—so there’s no point in putting on nutrient to grow 100 tonnes a hectare.
But the other end of the paddock might have good soil and a yield potential of 120 tonnes a hectare, so you put extra fertiliser on there. Overall you might be still putting on the same amount of fertiliser, but only where it’s needed and the plant will take it up before any losses occur.
That machinery is available to growers, and we are trialling it at the moment.
Being open to new practices and trialling ideas for your farm
My philosophy is to be open-minded to anything, even if you don’t think it’ll work. Just because it’s different to what you’ve done, you can’t assume it’s not beneficial for your farm unless you try it.
We’ve recently started a very small trial project. We saw a cane grower in Mackay who is doing what is called skip-row planting. He’s planting 1.9 metre rows as we are, but not planting every second row of cane. He leaves it fallow for 5 years, then plants the fallow row and fallows the cane row, breaking the monoculture cycle.
Many people believe you could never economically grow cane like that, but research figures show he’s making more dollars per hectare. The idea came from the grain industry, where they do it for moisture. I didn’t think it could work but I was wrong—so in 2011 I planted an acre to try it.
We’ve tried quite a few things over the years.
For example, using very low rates of nitrogen. We put very limited amounts of nitrogen (about 28 kilograms per hectare) on our cane, and got good results one year, not good results the next, then the trial paddock was flooded.
The idea is that, under the right conditions, the cane will fix some of its own nitrogen. It’s something that needs more work, but we’re keen to explore further because fertiliser is the second-largest cost in producing sugar cane (harvesting is the largest).
Interview date: 1 July 2011
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