# Haystack Fires in Australia: Causes and Considerations for Preventative Management
###### Abstract  
The spontaneous combustion of hay when stacked after baling is an issue frequently encountered by farmers in Australia and elsewhere. While there is a basic understanding of why this occurs the interactions of the many factors involved mean that there is still no consistent methodology for its prevention. Recent technological advances in sensors and communications allow for the continual collection of quantitative data from hay bales or stacks for managers to utilize in their decision-making processes with regards to minimizing the risks of spontaneous combustion. This review discusses both the factors involved in the spontaneous combustion of haystacks and the types of sensors available for the monitoring of these factors. This includes advancements in sensor technologies and their practical applications in monitoring hay bale conditions.  
spontaneous combustion; high temperature; remote sensing +
Footnote †: journal: _agriculture_  
0000-0002-2323-2233-2233-2233-2233-2233-2233-2233-2233-2233-2233-2233-2233-2233-2233-2233-2233-2233-2233-2233-2233-2233-22333-2233-  
peat, bituminous coal, lignite coal, animal fat, vegetable fat, rapeseed, oil plants, seeds, plant waste, animal feces (manure) and cellulose pulp, etc. This paper primarily focuses on the facts and considerations of the spontaneous combustion of hay. Over the years, many post-fire investigations have shown that experts were unable to correctly identify the causes of fire. This is due to a lack of studies and publications on spontaneous combustion and limited knowledge in thermodynamics, chemistry, biology and physics [6]. Surprisingly, the spontaneous combustion of hay is not yet fully understood by agricultural producers and warrants a more comprehensive investigation.  
The spontaneous combustion of hay products in Australia poses a significant economic and health risk for the producer. The value of pasture (including lucerne), cereal, and other crops cut for hay in Australia exceeded AUD 2.5 billion in 2020 (Figure 1). The ability of producers to safely store and manage their fodder usage is curtailed by the complex nature by which it degrades. Spontaneous combustion in freshly baled hay is a frequently encountered problem with hay production. In Australia between 2019 and 2022 the Insurance Australia Group received 60 insurance claims valued at AUD 2.6 million hat were attributed to the spontaneous combustion of hay. It has been established that the interaction between moisture and sugar content is an important determiner of hay self-heating. Additionally, other factors of spontaneous combustion such as pale size, pale type, environmental conditions and storage conditions are reviewed. The two phases of spontaneous combustion are also examined to provide leads for the best management practices.  
Finally, we introduce the utilisation of'smart agriculture' to streamline the management of hay susceptible to degradation through spontaneous combustion. The use of the Internet of Things (IoT), sensors and communication devices is also discussed. Additionally, the requirement of smart agriculture to be secure and private is investigated.