Harvesting Moist Grain Pays a Premium
Eastern Australia’s 2010 wet winter crop harvest has led grain storage specialists to urge growers to “push the envelope” when it comes to harvesting grain at higher moisture to capture greater financial returns. They say growers have to overcome the psyche that cereal harvesting can only start at 12 per cent moisture.
Andrew Kotzur, who runs grain storage construction company Kotzur Pty Ltd, has urged growers to look the success of farmers in Europe and America who regularly harvest at 20 per cent moisture and above, and air dry grain to lower it to meet buyer requirements, as something which could be achieved in Australian conditions. He cites examples in 2010 of northern NSW wheat growers harvesting wheat early at 15 per cent moisture prior to the onset of wet weather, ensuring premium quality and achieving up to a $200 a tonne premium over the feed wheat which resulted from weather damage.
“We are standing on the edge of cliff in many grain growing regions – not knowing if we are prepared to jump and start harvesting grain at 14 per cent moisture and higher. Research has long proved this is not a problem and with good aeration facilities a degree of management is returned to the grower in challenging conditions,” he says.
“I took phone call after phone call in 2010 from growers asking if 14 per cent moisture was too high to bring the header in, but the if you have aeration capabilities in your grain storage, bringing it back to 12 per cent becomes quite simple and it’s a form of insurance for a crop which has cost a lot of money to grow.” Victoria based grains storage researcher and consultant Peter Botta, of PCB Consulting, supports Andrew’s comments after facing two months of continual telephone inquiries from growers seeking advice on storing moist or weather damaged grain.
“The issue is even bigger than just having the facilities to dry grain out – in much of eastern Australia growers don’t even have adequate facilities to just store and manage grain,” he says.
“While we might think the last harvest was wet there seems to be a pattern emerging of wet weather or summer storms affecting harvest which we have seen in the past four years.”
The benefits come not just having a higher quality grain but from being able to start harvesting earlier – which is attractive to contractors; harvest for longer periods of the day and if the cereals are harvested early growers can then move on to pulse crops, which quickly decrease in value and yield when weather damaged.
The issue goes even further, according to Peter Botta, who believes there are social and health implications from long, drawn out harvests impacting on rural families, communities and businesses. “After 12 weeks of harvest some farmers are not nice to be around. Part of that is because of the lack of control over their environment around but having more and better grain storage gives them back some control,” he says.
“Timeliness has been proved to be one of the most crucial aspects of good farm management. Better timeliness of harvest means more timeliness when it comes to spraying summer weeds or preparation for sowing.” While Kotzurs have anecdotal evidence of Australia growers harvesting grain successfully at 18 per cent, trials at Kotzurs’ Walla Walla facility in southern NSW, have shown wheat harvested at 16 per cent moisture can be efficiently dried to 12 per cent moisture while retaining quality. The key to success is having the system that allows you to manage the harvest properly,, Aeration cooling and aeration drying are very different and planning and correctly managing the harvest and storage system is essential.
Growers planning to start harvest earlier due to a looming wet harvest period, contractor availability or a large area have numerous options: 1. To seek markets which are prepared to take delivery of higher moisture grains, such as the stockfeed milling market. 2. To harvest grain and store grain at 14 per cent moisture and hold it at that level using cool aeration for a period before blending with drier grain for delivery. 3. To harvest grain at a high moisture content, store it in a drying silo and using high flow aeration dry it down over a period of days or weeks depending on the atmosphere’s humidity. 4. To harvest grain at high moisture content and dry it quickly by passing it through gas or mechanical dryers attached to the storage complex. To maintain grain moisture content costs approximately 10 to 20 cents/tonne/month and to silo dry grain costs around $1-$2/tonne depending on starting moisture and humidity levels. Using a gas or mechanical dryer (which generates hot air to be circulated through the storage facility) costs about $5-$8/tonne.
The Kotzur drying silo uses a specially developed and patented drying cone/plenum. The air is forced into this plenum and then passes through the grain mass. Different drying silo models, fan combinations and grain have varying specifications; however, the typical airflow is 25-50 cfm air flow per tonne of grain or a complete change of air in the silo each 25-50 seconds. This airflow is 10 to 15 times that achieved using conventional aeration.
Purchased for lower capital cost than conventional grain dryers, drying silos offer lower energy consumption, less grain handling, gentle drying and fast aeration without needing screens or perforated floors which can restrict airflow or need cleaning.
The moisture content that grain will dry to is determined by the average condition of the air used. To calculate if air of a certain quality will or will not dry grain, growers can refer to the Equilibrium Grain Moisture Contents table (go to www.grdc.com.au or www.storedgrain.com.au) or use an automatic drying controller – which are generally fitted to most new drying silos.
Aeration is not a set and forget exercise with silos regularly needing inspection – particularly if high moisture grain is involved. Fans, ducts, vents and controllers all need to be checked regularly and a sweet fresh smell should be detected around the silo. A musty/mouldy smell can indicate a problem with air circulation within the grain.
For more information: www.kotzur.com or pbotta@bigpond.com
