TREBONNE, NORTH QUEENSLAND, 1.5 HRS NORTH OF TOWNSVILLE
We caught up with Michael in October 2018, hear what he is up to here.
Commodity: Sugar cane
Farm area: 133 hectares
Rainfall: 1.5-4.0 metres rainfall per year
In the last five years, I think that the forecasts – especially the Bureau of Meteorology’s 5-day forecast – have improved enormously. The improved forecasting has helped me make better decisions, which has helped me get greater returns out of my farm because I’ve been able to do or plan operations for a more beneficial time.
We’re in Trebonne, which is in the Herbert Valley in north Queensland, about 1.5 hours north of Townsville. My parents have been farming here since the mid-1950s and I took over in 2000. Before that I was a sugarcane agronomist with Herbert Cane Productivity Services.
We farm about 133 hectares of sugar cane over 3 separate properties, and produce about 9000 tonnes of cane annually. Our worst year was 6500 tonnes and our best year is about 11,500 tonnes on the same area of land, so you can see we get huge variability in our production.
The Herbert River is the major river system in the district, and it forms a valley which floods regularly.
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 per cent 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.
We don’t irrigate the farm because our average annual rainfall is about 2.5 metres.
The wet season is generally between December and May. The dry season, June/July, is usually low rainfall but cool and wet.
Then with the heat we get in August/September through to November/December, we have a dry period. 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.
In 2011, we recorded almost 4 metres of rain on this property. A very dry year is about 1.5 metres. During what we call our dry season we have occasional rainfall, but not excessive and not constant. But too much rain, not too little, is our biggest problem on nearly all occasions.
Wet years can be disastrous for the industry because they interfere with crop growth and then harvesting (the ground won’t carry the machinery). It also affects the ratooning of the cane and our ability to control weeds.
Our harvest period starts in mid-June to early July, and goes through until mid-November.
2013 was a fairly dry season after a big wet season in 2012. We had a wet winter, and then it stopped raining in about August and didn’t rain again until about end of November, which is excellent for harvesting, but the young cane that was trying to grow was struggling for moisture.
Excessive rain gives us two major issues: One is lack of sunlight – we get very little sunlight when we get that constant rain, and you need plenty of sunlight to grow a crop. The other thing you need is plenty of moisture, but not too much. That’s the other issue with those wet years: our ground was waterlogged.
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 we can. Even in the good years, our crops can be at less than 100 per cent because they are still suffering from past years’ damage.
Our big ‘weather decisions’ are when to plant, when and where to harvest, and the timing of fertilising and spraying. Confidence in long-term forecasts makes these decisions easier and helps me make the best decision.
In the last five years [2009-13] I think that the forecasts – especially the Bureau of Meteorology’s 5-day forecast – have improved enormously. I don’t criticise the Bureau because I know that it is very difficult to forecast weather in the tropics. But I feel that in the last 5 years there’s been a huge increase in the accuracy. Before that it seemed to be hit-and-miss.
The improved forecasting, and the longer term ones especially, have helped me make better decisions, which has helped me get greater returns out of my farm because I’ve been able to do or plan operations for a more beneficial time.
The short-term forecast is also a great help, for planning spraying and fertilising operations.
The forecasts I look at are the seasonal outlook on the Bureau of Meteorology site – specifically, whether it predicts above- or below-average rainfall.
I also look at 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, median or below-average rainfall to the Southern Oscillation Index (SOI), plus forecast percentage above- or below-median rainfall.
We get that forecast every month for 2 months ahead, and it’s based on the Bureau of Meteorology’s SOI, but localised for the Herbert. It has missed a couple of times, but generally it’s a better indicator than none at all.
If the longer term forecast is for a wetter-than-average year, I’ll probably hold off planting because the last thing I want to do is plant and have 5 or 10 inches of rain so the cane ends up sitting in water – then we have to do it again!
For planting legumes, I go more on how the weather is going in the year instead of the forecast – we wait for some sort of rain and then plant. For instance, after a crop of cane, if we haven’t had rain, the ground’s very dry and we won’t put soybeans in because they won’t survive.
If there’s a forecast that it’s going to rain in the next 5 days, I hold off fertilising until after the rain. I also use the longer term forecast to plan whether I’ll be applying fertiliser earlier or later in the season.
The short-term forecasts are more useful for decisions such as when to spray. The long-term forecasts are useful in planning whether to use a pre-emergent chemical or knockdown [herbicide].
I use a long-term forecast for planning harvesting schedules: our harvest machinery rotates around a local grower group. [Each farmer harvests a percentage of this crop, then the next farmer does the same, until all the cane is harvested.] It takes about 5 months to mill our crop and turn it into sugar.
I’ve got 3 locations on the farm. One is in a wet area but is very well drained and accessible quite quickly after rain. Another is in a wet area, but it is poorly drained. The last is in a dry area and is reasonably well drained.
When a wet year is forecast or above-median rainfall is forecast, I’ll harvest that wet area at the first opportunity I get because, if we get more rain, you can’t get the machinery in there.
In an average year, or below-average rainfall prediction, I’d normally harvest the dry area earlier because the crop will run out of moisture if I don’t harvest earlier. But these decisions mean leaving some of your other areas vulnerable.
For instance, ‘plant cane’ [the first crop after planting] and first ratoon [the regrowth 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.
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 increased the amount of cane I was able to harvest.
10 years ago, I heard of some growers in Mackay planting 2 rows of cane [‘dual-row’] on a mound on a 1.9-metre wheel track – instead of the usual 1.5-1.6 metres.
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. Each cane harvester weighs 24 tonnes.
We looked at the positives and negatives of doing dual-row planting, and decided to put a small trial in on a friend’s farm. It was a success – we were happy with the outcome. We didn’t grow any more cane, but it cost us less to grow the same amount of cane because there were less input costs.
I changed to a 1.9-metre row spacing (the width of the harvesting machinery) and I use controlled traffic and GPS auto-steer.
I 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 risk of waterlogging, compared to the conventional method of planting in a furrow 3-6 inches [7-16 centimetres] below ground level. By not disturbing the soil, we conserve moisture that we might need, and reduce weed emergence.
After we spray our legumes out, we do two cultivations: we chop up the grass with a set of discs, then use the ripper hoe/mounder to re-form the soil mounds.
We re-form the mound so that they’re a constant height and shape, so that the harvester can do a better job of picking up the cane cleanly off the ground. In the next month we’ll plant the paddock to cane.
The tractor uses GPS to go back to exactly the same spot again and re-form those beds, so our soil health should be improving. Hopefully we’ll see yield improvements in the next crop cycle.
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. Controlled traffic and cultivating only in certain zones reduces soil compaction, improves trafficability, helps water infiltration and increases microbial activity in the soil.
I’d like to do zero cultivation, a no-till system. We’ve tried a little bit of it and it’s been unsuccessful so far. We haven’t been able to work out how to do it yet. Because we don’t have a little seed to put in the ground, but a whole stalk of cane, the soil needs to be all around the stalk to get good germination. Without some cultivation, we seem to struggle to be able to do that.
If you don’t get a good establishment at the start you’ve got 5 years of losses.
We plant 2 rows of cane in that 1.9-metre space, but now we’re trialling only planting every second row of cane – this is called ‘skip-row’ planting. The idea really came from the grains industry, where they were skip-planting sorghum around Emerald (in central Queensland).
We’re going to take this through for 5 years, harvest that cane, then plant the rows that didn’t have cane on them for 5 years. This way we’ll effectively have fallowed each strip of ground for 5 years.
We’d expect around 90 tonnes per hectare of sugar cane from a normal paddock on this country. If we could harvest 75 tonnes per hectare with skip row, I think that would make it a viable option, and with the potential of growing more cane after the 5-year fallow in the skipped row.
Apart from spraying costs, your input costs are halved for everything, and overheads are fixed, so we’ve estimated that to break even we need to grow about between 70 and 75 per cent of the yield that you would under a conventional system.
If you can break even or get the same return per hectare for the first 5 years when you plant the land in between, we believe the big benefit will be that you’ll get far greater yields because of the fallow.
If, 5 years ago, somebody told me to plant every second row to grow 70 per cent of the cane, I’d tell them they were an idiot.
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.
- The skip-row system is great for breaking the monoculture of sugar cane – monoculture in any industry is bad for soil health.
- There is less competition for moisture, nutrients and sunlight than in a conventional system.
- This system reduces our overheads.
- It allows us to grow a legume crop in the skipped row if we want – when the cane is small. When we take that legume crop out, it would supply some nitrogen to the cane crop.
- It’s normally very difficult to access a paddock of cane, but not with skipped-rows. We can really see what’s going on in the paddock, so it makes it easier for weed control as well.
We are also trialling within-block variable-rate nutrient application – varying the rate of applied nutrients depending on the yield potential of that part of the block.
Variable-rate nutrient application isn’t new in a lot of industries, but it is unproven in the cane industry. Yield mapping is just one part of the process – grower knowledge, drainage, pH and organic carbon levels all play a part in coming up with what nutrients need to be applied where.
We measure electrical conductivity in the soil [which indicates the ability of soil to hold nutrients] with a Veris machine to establish ‘zones’ in each paddock. We take GPS-linked 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.
On my farm, I’m mapping every block as I fallow it to get an understanding of what’s where. I’m hopeful that I’m not too far away from variable-rate nutrient application [Michael estimates 2016].
For instance, the general rate of applying lime on acidic, tropical soils is 2.5 tonnes per hectare every 5 years. We’re finding that some areas of the block need 5 tonnes per hectare, some don’t need any, and some need 2.5 tonnes per hectare.
Variable-rate nutrient application also has water-quality benefits because if you put the nutrients in the spot the cane uses it, less gets lost and it’s economically beneficial too – a win-win. For our industry, it will be maybe 10 years off being a normal practice, though.
Because fertiliser is the second-largest cost in producing sugar cane after harvesting, losing nitrogen from our soils is critical. Our main nitrogen source in the cane industry is urea – it’s the cheapest form of nitrogen.
In the big wet years, we lose nitrogen in 3 ways: up to the atmosphere through denitrification, gets leached away, or washed off in surface water. We’d like to know more about how and where the nitrogen is going.
Measuring where that nitrogen is going is quite difficult in those conditions, as you can imagine, but James Cook University scientists are trying to do that in a couple of projects in the Herbert Valley.
We take steps to control nitrogen loss: by putting our nitrogen under the ground so that it’s not lost to the air and being washed away by heavy rainfall.
We plant legumes as a rotation crop to break the sugar cane monoculture cycle and improve soil health. There are some nitrogen benefits, too. Whatever survives the wet is good!
Soybeans are the best in wet years – they also make the most nitrogen – but they’re very temperamental so you have to have really good seedbed preparation, have good moisture and plant them at exactly the right depth.
Cowpeas take less seedbed preparation and you can plant them into dry ground – when you get rain they germinate. I spray the cane out, then plant them straight into where the cane was with the [sugar cane] trash. We use a specialist planter owned by the local productivity group because the trash is quite thick and very strong.
In 2011, 2012 and 2013, the legumes were half a success – we had quite a lot of rain and floods – it was barely dry enough to plant them. In 2010, we didn’t plant any legumes and we had trouble just getting on to spray the fallowed country to take the cane out, that year. But if we had planted them they would have drowned with the weather that followed, so we saved ourselves some money on seed and fuel.
In the first half of 2013, it was a fairly dry time, so our legumes on our other farms were excellent crops. They’d been on the mounds to keep them out of the water when it had been very wet, and they’ve done very well.
Although we can measure soil nitrogen, that doesn’t necessarily indicate how much is available to a plant. After a legume crop when you come to fertilise the cane, there’s no way of knowing how much nitrogen is there from the legume crop. You don’t know how much fertiliser to put on to your crop, so I usually work on getting about 50 kilograms of nitrogen from the legumes per hectare.
So even though each year and its different set of circumstances gives different levels of available nitrogen to the plants, it’s still worthwhile for the crop rotation. Sometimes it’s a bit hit and miss, but I’m not going to stop doing it unless somebody comes up with something better to plant as a rotation crop. 6 out of 10 years they survive and do well.
Since I’ve been part of the MCV Climate Champion program, I’ve learned a lot more about climate variability and climate change through our meetings and talking to scientists.
When I started in the program I was a sceptic of climate change. But now I can see clearly that climate change is real – the evidence is there and, as farmers, we have to deal with it.
Whether we call it climate change or climate variability, we have to deal with those changes and make the most of them.
I think that the MCV Climate Champion participants would benefit from a ‘rotation’ plan with the people taking part – new people joining groups bring in new ideas.
And like the MCV Climate Champion program, where we get together and talk about climate, another project I’m involved in is Project Catalyst. They are both networks which build your interests, and strengthen your resolve to change things and think outside the square to trial new ideas.
I work 3 days a week as an agronomist for Project Catalyst, helping growers who want to trial a new farming practice to plan, research and lay out trials. It’s about improving water quality and improving farming practices so that they’re both economically viable and sustainable. The technical and economic support is vital for growers like myself who want to try new things.
Interview dates: July 2011, 13 May 2013
Michael Waring crops sugar in Trebonne, Queensland
Ratoon cane regrowth
This sugar cane is about 2 months’ off harvest
Flooding is frequent at Michael’s property.