John Holman

John Holman

Murray County Extension Educator Ag/4-H Youth Development

Spring and early summer cuttings often present the greatest risks for hay fires because of the difficulties of drying hay before baling. No matter the time of year, if rain is in the forecast, hay producers are often tempted to bale at a little higher moisture content to avoid weather damage. If hay is baled too wet and packed too tightly into storage, severe heating can occur causing significant dry matter and quality losses or worse – a hay fire.

Heating results from plant respiration and microbial activity. It can occur in baled hay at moisture contents as low as about 13%. Therefore, heating is a natural occurrence with temperatures reaching over 120°F even in hay baled at safe moisture contents. If excess moisture is present, heat resistant fungi become active which can drive the temperature to over 150°F. Above about 170°F, the microorganism’s die, but heat-producing chemical reactions continue to drive temperatures up. Between 180° and 212°F, spontaneous combustion can occur if the material is exposed to air.

Hay fires can occur over two weeks after the hay is placed into storage. Generally, temperatures below 140°F indicate no particular heating problem. Check the hay daily to see if temperatures continue to rise. Temperature readings between 140° and 170°F provide no clear indication of pending problems. Check the temperature every few hours to monitor changes. If the temperature is above 180°F, there is increased risk that combustion could occur. DO NOT MOVE THE HAY UNTIL THE FIRE DEPARTMENT IS PRESENT. When smoldering hay is exposed to air, it can undergo spontaneous combustion.







To read more please log in or subscribe to the digital edition.

Sulphur Times-Democrat

P.O. Box 131
Sulphur, OK 73086
PH: (580) 622-2102