Some unexpected haystack fires this month have raised concerns about how hay combusts spontaneously and how hay growers can better manage their stored hay.

According to hay grower and Group Officer of CFA’s Buloke West Group, David Maniold, two cereal haystacks stored outside without caps have caught fire. These fires near Donald and Birchip are unusual as they have occurred well after the typical danger period of late spring and summer.

While the winter rainfall and recent daily maximum temperatures between 27-30C could contribute to a higher risk of fire, more knowledge is needed to understand how to manage the risks.

Moisture and storage conditions are well recognised as a key factors with hay fires. Tractor wheels can also run over a large windrow near headlands, leaving a compressed mass of hay that cures more slowly than the rest of the paddock, adding moisture to some bales. Despite this the industry is still unaware of why some haystacks with the same moisture content and shed types burn and others don’t.

Often research from overseas can be applied to agricultural practises but spontaneous combustion in cereal hay is a uniquely Australian problem.

Global hay production is heavily based on mixed pasture, lucerne or irrigated grass crops such as Rhodes grass.

Spanish oaten hay does compete aggressively with Australian product in Middle Eastern and Southeast Asian markets. However, the irrigated growing conditions, lower sugar content and the dehydration process through gas-fired driers provides Spanish hay with a lower risk of combustion.

Apart from the obvious financial loss of hay inventory, farm infrastructure and stored machinery, there are wider implications for hay fires.

Fire authorities are often troubled by hay fires when limited resources can be regularly allocated to control and contain hay fires at a time when the risk of much larger grass fires is at its annual peak.

It is pleasing to see the hay sector commit research funding to address this issue.

Through a mandated $0.50 per tonne levy applied to exported hay, collected by exporters and matched by the Australian government, AgriFutures has undertaken research to assess the scientific validity of microbial fingerprinting to profile fire risk in hay.

In a report to be published next month, an AgriFutures-funded project has found that the microbial makeup of hay windrows do differ.

Using isothermal microcalorimetry that can detect and measure minute changes in heat flow and cumulative heat during microbiological processes, researchers have replicated the conditions that create spontaneous combustion and associated them with the genetic profile of each hay sample.

Predictive models can be used to determine if hay samples contain microbes that are either ‘hot’ and likely to cause fire and those that are ‘cold’ and have a lower risk of heating.

Researchers are hoping to create a commercial diagnostic tool that can be used to identify the heating risk profile during hay making. Low moisture hay is still critical but the high yielding hay crops this season are not expected to have a high risk of heating.