Hot Fun in the Summer Time: Ear Leaf Tissue Testing

It was July, almost August. And was HOT. I was burrowing my way through six foot tall corn in 100 degree temperatures! Last month I told you about testing the soil to get a read on how much nitrogen (think plant food) there is next to the corn plants to help them grow. We did that BEFORE the farmer gave the corn any additional fertilizer which made it a Pre-Sidedress Nitrate Tests (PSNT).

As a crop advisor for the BMP Challenge, I revisited the fields at the end of July to take Ear Leaf Tissue Samples. The plant’s silk coming from the top of the ears is still yellow but just about to turn brown meaning it’s our last chance to check up on the health of the plants prior to harvest. Walking the length of the field (about two football fields with 6-foot corn means I hadn’t seen daylight for 30 minutes!) and I periodically pulled off a leaf, the one that grows at the base of the ear of corn, to collect samples for testing.  Being in the field also gave me a chance to examine the crop for signs of stress, such as withered leaves from drought, yellowed leaves due to low nitrogen and insects.

These samples taken in BMP Challenge enrolled fields come from two areas: first from the “check strip,” where the farmer had applied nitrogen at a rate of his or her own choosing, and then from the remainder of the field where the nitrogen rate was determined by the PSNT results.  The samples of ear leaves help backup the PSNT results, showing that the portion of the field that had received a reduced amount of fertilizer would still have adequate nitrogen to make it through harvest.  But maybe even more important, the ear leaf test provides another data point, another topic to discuss when we sit down as a group with the participating farmers after the harvest. As a crop advisor, I work to provide BMP Challenge enrolled farmers with all the information to ponder, discussing their observations and the test results against their yields to evaluate the use of best management practices on their field.

The PSNT and Ear Leaf tests just provide a snapshot of the nutrients available to the plants on the day the samples are taken. They give the farmer one more piece of the complex puzzle that is nitrogen fertilizer management.  Much research has been done over the last several decades to determine the amount of each nutrient that is necessary to support growth. Mother Nature is unpredictable and soil types differ from farm to farm, so each farmer must have their management strategies. At the same time, it is impossible for any single test or guideline to consistently provide the “right” answer about how much fertilizer a farmer should apply.  The main reason I was out in the summer heat, melting and collecting the ear leaf samples was to give each farmer one more measurement of their crop’s progress in order to evaluate the recommendations that we made to them after the PSNT.

When people my age leave Virginia Tech with an ag degree and look at today’s economy, they know they will have to be innovative in order to remain profitable if they want to farm  The “slippery fish” of nitrogen that I work with as a crop advisor requires extra attention; it’s risky and being wrong is expensive. AFT’s BMP Challenge program is providing access to tools and knowledge to help farmers better manage their fertilizer usage. By offering insurance, AFT is encouraging producers to try new practices on their fields—like the one I walked through that hot July day—and not lose sleep at night worrying about yield loss. Using fertilizer more efficiently meets the double bottom line that farmers want: to improve the water in the stream while getting the most corn at the least cost.



About the Author: Dana Gochenour is a farmer and freelance writer in Virginia’s Shenandoah Valley. She can be reached at dgochen@vt.edu.

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