Compacted Roots May Haunt Some Cornfields

Compacted Roots May Haunt Some Cornfields

Worst of all worlds setting up for fields planted wet.

Sometimes dealing with soil compaction is a cost of doing business, or so Gary Steinhardt says. He is a soil Extension specialist at Purdue University. Steinhardt is one of the first researchers around the country who began looking at soil compaction as a cause of tall corn and short corn, and related yield losses, in the early 1980s.

A cost of doing business means that if the crop has to come out, as in the fall of 2009, or has to go in, as this spring, it may be necessary to go when it's a bit wet and take the chance that the yield hit won't be great. When it keeps raining, the effects of soil compaction may be minimal. If it stops raining, then the effects can translate into lost bushels, especially on corn. Even through his research at the time, Steinhardt was hard pressed to show consistent yield loss with soybeans even after heavily compacting the soil.

Well, the worst of all possible scenarios is playing out, especially for those who planted around May 21 to May 23, when corn was then hit by a hard rain and emergence wasn't great. Many fields planted in that time frame in parts of Indiana were 'just a bit tacky, but I'll plant anyway.' Unfortunately, that is the exact best time for soils to compact. If you're going to build a road, you wet the soil and that's when you drive over it and firm it up and pack it down, experts say.

Judging at county fairs this summer, I've noticed some plants with obvious flat root systems. Instead of going over in a nice half circle, with plenty of hair roots underneath, they look like they hit a flat iron, and then went sideways. That's because roots had trouble penetrating the compacted soil.

Now comes excessive heat without rain. Right when plants need a very large, very deep root system, with lots of hair roots to feed the plants, they're not there. The result could be more stress than you might expect showing up in fields or parts of fields where it was wetter than you like when you planted.

The only remedy this year is to pray for rain. Freezing and thawing over the winter will help some, but the compaction, especially deep spoil compaction, will likely still be there. If next summer is a wet one through the critical periods for corn, it may not show up. If it's another dry one, you may see the effects in corn. 

TAGS: Soybean
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