Dr. Fred Below, University of Illinois research agronomist, has conducted some research that he calls the "Seven Wonders of the Corn Yield World" This research has focused on the main factors that influence corn yield, while some of his observations were obvious, some were items that you wouldn't think would be quite so important.
First of all, the pre-requisites for the research were that we had good pest and weed control. This is an obvious one and we know that without good weed control, for instance, we will not realize the full yield potential of our corn crop. The second pre-requisite is that we had adequate levels of Phosphorus (P) and Potassium (K) as well as proper soil pH. The latter is especially important as important soil nutrients such as P and K are not available under low ph conditions. And finally, the study allowed for a one-time improvement such as drainage to be considered in the research. Following, ranked in order of importance, are some of the observations from Dr. Below's research.
Tina LeBrun and Wayne Schoper
This seems rather obvious, but we forget that weather includes not only the amount of rain that we get but also the temperature, wind, hail, clouds and temperature. If any one of these is out of wack we can have a major problem. No rain during the month of July, for example, negates a lot of good crop husbandry. The dry weather that affected most of the Corn Belt including Minnesota continues on through this winter. Actually, when you think about it, all the best inputs mean nothing if it doesn't rain.
Corn is a grass and thus needs supplemental nitrogen fertilizer in order to grow and yield the way that we want it to. Legumes such as soybeans fixate their own nitrogen from the atmosphere. Cutting nitrogen rates in an attempt to save money can lead to disastrous results.
3. Hybrid Selection
We have had a tremendous improvement in corn hybrid development in the past 20 years. Corn hybrids from the 1980's would have collapsed during the last two summers due to lack of consistent moisture. A good corn hybrid can make a lot of difference on your farm. However, while weather still plays the largest role, care must be taken to select the right corn hybrid for your farm. Varietal trials show yields from 129 bushels an acre up to 216, an 85 bushel an acre swing. Figuring current corn prices at seven dollars, this adds up to a potential of $595 per acre!
4. Previous Crop
We do know that we can give a nitrogen credit of 40 50 pounds to a previous crop of soybeans. When corn is grown continuously, residue from the previous year's crop will cost more yield each year that corn is grown. The biggest hit on yield on corn-on-corn doesn't occur in the second year; it just that producers tend to forget about it after the second year.
5. Plant Population
Corn seed is not the item to cut to keep costs down. The optimum population for soils without compromises is to plant around 34,000 to 35,000 seeds per acre.
There are issues between timing of tillage operations and type of tillage. Tillage also plays an important role in saving soil and retaining valuable moisture and nutrients.
7. Growth Regulators
Growth regulators include those compounds that have a positive impact on plant growth. Protect against foliar disease with a strobilurin fungicide and you will see greener leaves and healthier plants.