This harvest season I have found a few things that I thought would never be true. A few of the producers I work with noticed a significant yield reduction in certain fields that we assumed was due to high levels of salt or just poor ground. With curiosity, I went out into these fields with a handheld soil probe and tried to get soil core samples. After struggling to get the probe into the ground in several spots, we decided to get an excavator and dig root pits. We dug multiple pits across and lengthwise with the rows. We came to the following conclusions: soil moisture is still good after 6 inches of dry soil; disking, coultering and even chisel compaction layers exist in some of the fields; soil tilth was severely increased or decreased due to tillage and/or lack of tillage. I also found no-till fields that had awesome soil tilth and very little compaction.
This picture above shows what happens when soil compaction is developed. The roots stop penetrating after 6 inches and start growing laterally.
We had more moisture than most of the state this year, but we were still very short. Some producers that I work with did a bit more aggressive tillage last fall and it paid off to the sum of nearly 20 bushels per acre. Am I recommending deep ripping everything? No. I think if there is a problem with compaction or soil tilth, then we need to take actions to correct it. In some of the pits, you could see the roots go lateral at 6 inches and wouldn’t penetrate any deeper. Where the ground was deep tilled in these severe compaction or tight soil areas the root mass was 10 times larger. These roots also penetrated to rooting depths of over 36 inches compared to where the ground was just chiseled, finished and disked.
This depicts how root growth is more advanced after fields plagued with soil compaction are ripped. The roots in this picture are 36 inches in depth and show significant lateral growth.
If you’re seeing spots in fields that are stressing or showing a lack in return, maybe it’s time to consider looking at your soil compaction or soil tilth. The mini excavator was the tool that made this issue visual and understandable to the naked eye. Assumptions hurt production so you’ll need to dig the root pits in the trouble fields to tell what the problem is. If there isn’t soil compaction or tightness then deep tillage is not the answer, but if the severity of compaction and the lack of tilth is at levels like we discovered it may be time to take action.