Source: Penn State Extension

By Greg Roth

Wheat harvest has started and it’s time to strive for timely harvest management. Nothing good happens when ripe grain gets wet.

North Carolina State University has studied this issue. Here are a couple of conclusions from their study.

  • Each time mature grain gets wet after maturity, test weight drops by about 1 pound per bushel.
  • DON tends to increase with delayed harvesting. In two of four tests, DON increased significantly and above 2.0 ppm with a late harvest. 
  • Falling number did not decrease with late harvest except at one location where the grain stayed moist for a long time.
  • Grain yields seem to not be affected greatly with delayed harvest (within reason).

We participated in a tour with wheat millers and elevators about a week ago. In general wheat yields seemed good, with many in the 90 bushel per acre range with minimal scab reports. We were surprised at the recovery of drought-stressed wheat. We were concerned about forecasts for rain prior to harvest.

To do a pre-harvest yield estimate on wheat, you can try this formula. It won’t be perfect, but should give you a ballpark estimate:

Yield bushels per acre = ((Heads per foot * Numbers of Spikelets * Kernels/Spikelet)/Row Spacing) * 0.48

Example = 50 heads per foot * 13 spikelets per head * 2.3 kernels per spikelet)/7.5 inches * 0.48

 =1495/7.5*0.48 = 95.7 bu/a