Following a rain week two weeks ago, we have been very busy. Last week was great weather for cutting soybeans. We moved across field after field and cut quite a few acres.

Though reports in the area have varied, we found most yields satisfying. Soybeans did get too dry though, and many were cut at moistures in the 9-10% range when the target is 13%. Cutting beans too dry does reduce yields. Going from 13% to 10% moisture results in almost a 4% reduction. 50 bushel beans become 48 bushels, costing the farmer $25 per acre.

Turn the page to this week, and the weather has been poor. It has rained, misted, or found some other way to keep the crop damp every day. It has been damp enough we have had to be selective on the corn fields we move to as downed damp corn stalks don’t flow into a corn head very well.

Corn yields have varied wildly and for the first time in a long time there has been little to no advantage to irrigation. In some cases it resulted in less yield.

Tar spot hits yields

Though tar spot isn’t new to us, one thing we have learned this fall is that this fungal disease is a huge corn yield robber that is not as easy to control as we had thought. During the summer, if the infestation of tar spot gets bad enough on the plant, it shuts down and dies prematurely, reducing yields and resulting in poor quality grain.

Just about every one of our fields had two treatments of fungicides. The early treatment was prior to tassel when canopy penetration was easier and was meant to slow disease that moves from the bottom of the plant up. Our second application came at brown silk; it was meant to protect the plant long enough to get a good start on grain fill.

We chose cost effective products that have worked well for us in the past, but our protection ran out too early. I wish we had done some side-by-side comparisons with ‘premium’ products.

This winter we will look at changes we can make to be more effective in the event we have another tar spot season like this. Since tar spot overwinters on residue, I’d say those chances are pretty good.

Agronomists are encouraging farmers to ‘stay in corn’ even when conditions are right for soybeans again. There is concern that stalk integrity in corn will not last very long this fall.

The opinions of the author are not necessarily those of Farm Futures or Farm Progress.