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In-Field Drying of Corn May Reduce Yield

Even though this is a soybean website, I recognize that many Mississippi soybean farmers also grow corn. Therefore, I like to convey interesting corn information that may benefit those farmers.

I recently came across an article that reports results from a Purdue University study that is of interest. The article, entitled “Kernel dry weight loss during post-maturity drydown intervals in corn”, provides insight into how leaving corn in the field to dry down may result in yield loss.

The results of the study that was conducted from 1991-1994 in west-central Indiana follow.

  • Physiological maturity of corn kernels, defined as the point of maximum kernel dry weight, occurred at an average 28.5% grain moisture content. The range was from 25 to 35%.

  •  During 3 of the 4 years of the study, dry weight of mature corn kernels decreased during drydown that occurred in the field. For the three hybrids used in the study, the rate of dry weight loss ranged from 0.6 to 1.6% per point of decrease in grain moisture content, with an overall average of about 1% per point decrease in grain moisture content.

  •  According to these results, if mature corn grain is allowed to dry down from 28 to 18% in the field, the estimated potential yield loss would be 10%.


The Aug. 12 2014 NASS report from the Mississippi office projects 2014 average corn yields for the state to be 178 bu/acre from 520,000 harvested acres. If this 1% yield loss is applied to this estimated yield, then a total of 12.5 bu/acre of yield loss will occur if corn with 25% grain moisture is allowed to dry in the field until 18% grain moisture is reached. Using a corn price of $3.60/bu, this can translate to a revenue loss of $45/acre in 2014. Using an irrigated yield estimate of 250 bu/acre, the loss could be as high as 17.5 bu/acre with an estimated revenue loss of $63/acre. Both of these losses are significant, but must be measured against the cost of drying grain that is harvested at 25-28%.

As stated above, these are results from a study that was conducted in Indiana. Thus, there is no assumption that these results will translate to conditions that occur during corn grain drydown in Midsouth fields. However, this may be a worthwhile issue to study under Midsouth weather conditions.

 

On a completely different note, the above NASS report projects that Mississippi soybean yield will average 48 bu/acre from 2.22 million harvested acres in the state. Hopefully, this forecast will hold true, which means that the state will have another record yield for the soybean crop.

Composed by Larry G. Heatherly, Aug. 2014, larryheatherly@bellsouth.net