Sometimes we are slow to see the obvious, especially when it’s something that we have been walking past all our lives. This happy oblivion is contagious since everyone else tends to follow along blindly.
A similar situation has existed in soil fertility for a long time, but it hit me like a brick one day when I was thinking about why some growers seem to have an advantage.
A difference exists among growers in this area, especially when it comes to corn yield. It’s uncanny how a few people consistently produce high yields while others are so discouraged by corn that they have given up on it. I am talking about differences in yield that are commonly in the 20 to 30 bushel per acre range, but that can reach 50 bushels or more.
For years I have been looking for a common denominator that would offer a clue as to why some of the corn does not produce more than about 120 bushels per acre even in a good year while only a few miles away growers on similar soils produce 150 or more. On occasion these higher yields reach 180 or more during the exceptional year with good rainfall.
The only idea I have been able to pull from this situation is that producers with higher yields stay ahead of the curve on their liming and fertilization, allowing their corn to have easier access to nutrients. Instead of trying to keep soil pH above 5.5 they maintain it consistently above 6.2.
Instead of trying to keep MSU soil test phosphate and potash levels at 50 and 120 pounds per acre, they keep these levels near 110 and 300 or higher. They also make sure that secondary and minor elements like Zinc, Magnesium, and Sulfur are not in short supply.
Those who have access to poultry litter go beyond these levels, their challenge being how to keep potash up to ratio with phosphate. And another “secret” to this is that higher yields usually come from fields where growers have been staying ahead of their soil fertility needs for several years. The change does not seem to occur in one year, but is the result of long term soil building. In these well-fed soils nutrients move deep into the profile to feed roots wherever they go.
I became convinced this might be the answer to my question when I noticed that one of the most productive cotton producers in the area made 160 bushels on corn that was planted for rotation. These fields were in the middle of an area where corn yields usually top out around 100. His aggressive fertility program looked like the key to the lock, and it agreed with what I had seen in other areas.
If this idea is correct, then it means that the issue is not that our land is poor, but that our practices are not supplying the crop at the time when nutrients are in greatest demand.
Other crops are also suppressed by this fertility management style, but cotton and soybeans don’t seem as sensitive. Ironically, growers with low corn yields probably spend almost as much on fertilizers and lime, but they are often working with a deficit rather than a surplus. You might say they are playing defense. Nobody ever won anything on defense alone, you have to play offense.
I expect skepticism about this “theory,” but for now it’s the only one I’ve got. For as long as I have been in this area I have heard farmers comment that our local soil “just won’t make corn.” But I am just stubborn enough to believe this may be a myth. Other factors including rainfall, drainage, tillage system, sunlight, planting date, variety, wildlife damage, etc., also play roles in the story.
We need to see our dryland corn consistently break the 150 bushel barrier unless rainfall holds us back. We should be able to do this in an era when the national corn yield record has been pushed to more than three times that amount.