Let Your Corn Talk to You!

Obstacles! This year has had its obstacles, hasn’t it? Out in our corn fields , each plant has had to fight hard through many obstacles limiting top yields. The greatest yield-robber was obviously moisture- related. Plants that did not drown out completely were more than likely damaged due to reduced root mass and lack of nutrient uptake.

But, the great Albert Einstein is quoted as saying, “In the middle of difficulty, lies opportunity”. And our cornfields, pre-harvest, are an incredible educational opportunity. The plants themselves can tell us whether they were deficient in nutrients this season or whether they were planted too deep or too shallow. And the ears can point out any pollination issues and whether the population planted fully utilized the field’s resources for optimal yield.

I’ve talked about conducting pre-harvest evaluations in the past, (ear counts, ear tip-back, node of ear development) and I can’t encourage you enough to make sure you do this type of pre-harvest evaluation. Another evaluation tool you’ll want to consider is a Basal Stalk Nitrate Test, developed by Iowa State in 1996. The real lesson learned through its results is how you did in this specific field, this year. It will be too late for any rescue treatments this year. But, you’ll learn a lot about this year’s crop that you’ll be able to use to make decisions about future crops.

The test is pretty simple to take. The plant needs to have reached physiological maturity, black layer, before you can take it. Cut an eight inch section of the stalk, six inches above the soil line from 15 different plants. Take from plants that look uniform in growth and from different areas in the field. Keep the stalks in a paper, not plastic, bag and send them to a lab for analysis (stalks can be refrigerated if shipping cannot occur immediately).

The results will be measured in ‘ppm nitrate-N’ and placed into ranges (low, marginal, optimum, and excessive). A low to marginal rating show that nitrogen was probably deficient throughout the growing season and will negatively affect yield. An excessive rating means that either nitrogen applications were too high or some plant stress (hail, drought, poor pollination) did not allow the nitrate in the plant to move into the kernels. Yield optimization will occur when the rating show optimum.

In the final analysis, your overall grade for your cornfield is yield/acre. But only looking at yield/acre is like seeing your final class grade, and never examining the questions you may have gotten wrong. Conducting a pre-harvest evaluation is like looking at those questions. It will help you become a better corn farmer, increasing profit by limiting possible future costs and increasing your yields.

So, get out into your fields prior to combining and let your corn talk to you. Evaluate some of the questionable spots. Look at ear development. Take some plant samples and do some testing. Become an Einstein and find the opportunities in the difficulty.