October 3, 2007

 

Some Iowa farmers finding weather-damaged corn, soy

 

 

Combines returning from corn and soy fields in portions of northern Iowa are carrying large quantities of low-quality, weather-damaged grain.

 

"Reports of grain quality problems in northwest Iowa have been received," said Iowa State University grain quality expert Charles Hurburgh. "These problems are attributable to the erratic weather patterns experienced in that region this season - little rainfall in June and July, extreme rainfall and wind in early August, followed by frost in mid-September."

 

Corn and soy, which had already been under significant drought stress, were then subjected to torrential August rains, and then languished in mud or standing water for weeks prior to harvest.

 

"Plants flattened or standing in water are a ready target for a much wider range of moulds than would normally be expected," said Hurburgh, who heads up ISU's Grain Quality Initiative program. "Elevator operators report cases of mould damage levels 5 percent and higher in the current corn and soy crops. Odour problems have accompanied the mould in a few instances."

 

Freshly harvested corn usually carries less than 2 percent mould damage.

 

Hurburgh warns that some of this year's mouldy grain may actually be dangerous.

 

"If you are planning to feed corn from flooded fields, it would be wise to get a mycotoxin analysis before harvest," he advises. "The wide variety of moulds on these samples may mean a range of mycotoxin possibilities -aflatoxin, vomitoxin, fumonisin primarily."

 

Mycotoxins are poisonous chemical compounds produced by certain fungi, that can quickly sicken or kill humans and livestock that consume heavily contaminated grain. The worst is aflatoxin, which is considered carcinogenic.

 

"We have had a few positive tests for aflatoxin - not a lot yet, and hopefully it stays that way - but we have had a few test for aflatoxin," said Joel DeJong, ISU extension field agronomist.

 

DeJong said all confirmed reports of aflatoxin - which thrives on drought-stressed grain - came from fields in two counties in northwestern Iowa that received very little rainfall from early May through most of July.

 

Although most corn in northern Iowa was fully mature at the time, a record-breaking frost which struck in early September did damage area oilseeds.

 

"The early frost in soy added some damage to green soy caused by heavy rain and wind," said Hurburgh.

 

Frost-damaged beans often carry higher levels of moisture and lower levels of extractable vegetable oil; an undesirable greenish oil which is more likely to turn rancid. Corn which was immature at the time of the frost will also tend to carry lower test weights.

 

The myriad quality concerns has prompted local farm officials to call on growers to isolate those damaged bushels from the remainder of their fall crop and to sell them as soon as possible, as they carry a far shorter shelf-life.

 

"The damaged or low test weight grain must be aerated immediately to reduce temperature and equalize moisture. Field damaged grain will not store beyond the winter months," warns Hurburgh. "Field damaged grain, regardless of reason, should not be mixed with good grain. Producers should harvest around water holes, downed grain and frost damaged areas."

 

Added quality and storage concerns may also be slowing down Iowa's fall harvest, which is forecast to be the nations largest. USDA said Monday that only 13 percent of the state's corn had been picked entering the week, compared to 60 percent in neighbouring Illinois. The Iowa soy harvest had reached 35 percent complete, compared to 43 percent in Illinois.