“Knowing what I know now, I would do it all again and foot the bill myself,” said farmer Garret Igleheart. “We’ve gone from just thinking we were doing a good job, to having the raw data to prove it. We are essentially playing a whole different game.”
In 2015, Igleheart joined a coalition of farmers trying a new tissue sampling protocol from AgriGold.
Tissue samples offer snapshots of a crop’s internal nutrition. Most farmers collect one-off tissue samples, hoping to diagnose perceived issues. But without a strategic plan, they could be leaving knowledge, and dollars, behind.
A yearlong commitment to routine tissue samples could provide a road map to better fertility management, says Josh Johnston, an agronomist for AgriGold.
The base tissue sampling protocol outlines six key occasions throughout the growing season based on growing degree units to collect samples. For a more detailed plan, AgriGold recommended weekly sample collections.
“My advice for any grower that would want to start tissue sampling would be to pull them once a week without making any modifications,” Johnston said. “Then, you can analyze that data through the winter and identify your shortcomings.”
It may be tempting to react to individual results and make applications in-season, but the real value is derived when all the data is compiled.
“At the end of the year, that grower has developed an outline of their nutrient flow for the course of the year on their farm, using their equipment with their fertility plan,” Johnston said.
With specific, time-stamped data, farmers can analyze how their crop used fertilizer applications, if at all.
“What was eye-opening to me was that the fertility that we’ve been using for years and years wasn’t even getting that nutrition into the corn crop,” Johnston said.
Making meaningful changes to fertility management with tissue samples is not always quick; the year following an intensive tissue sampling protocol is just as important as the sampling year.
Ideally, farmers plan to address issues identified in year one, but another full growing season is needed to evaluate success.
“We want to draw a protocol to address shortcomings, stick to the protocol, and analyze the year-two tissue data to see what worked and what didn’t,” Johnston said. “We will make changes from there. It is just really important that we don’t react to the tissue samples as they’re coming in.”
Igleheart started the intensive tissue sampling protocol in 2015 and spent the next four years testing fertility products.
Igleheart has found it is easier to start with high nutrient availability, which is more cost effective than trying to build numbers throughout the season.
Today, he uses a two times two application of nitrogen, phosphorus, potassium, boron, and zinc at planting. In-season, he applies foliar and pre-tassel fertilizers.
“We found things that actually bring higher nutrient levels into the plant,” Igleheart said. “When that turned into actual yield, it became part of the program.”
Availability isn’t the only factor impacting a crop’s nutrient uptake. Other management practices, such as soil samples, can provide a full picture of the crop’s health.
Inevitably, a tissue sample returns a low reading somewhere, says Daniel Kaiser, Extension soil specialist. “It’s a question of what’s the cause of that low,” he said. “Sometimes, if you get a low value, it isn’t necessarily something you can apply fertilizer to correct.”
Tissue sampling should be used with routine soil samples to get a full view of a field’s nutrient availability.
Intense tissue sampling protocols also come with the side benefit of getting farmers into their fields more often, allowing them to catch issues such as disease or pest pressure.
Igleheart, who lives in a river valley with high disease pressure, found that his disease management improved after committing to weekly tissue sampling.
“We were using fungicides but found we were only using them for one application, and we were doing it too early,” he said.
“No matter what levels we achieved in the plant, when we let them die prematurely, we lost a ton of yield. Finishing the season as strong as we started was the second piece that led to a lot of yield gains.”
Tissue sampling is fairly inexpensive, making it easy to fit into farm budgets even in years of low commodity prices.
While costs vary among labs, a farmer can expect to pay around $15 per sample. Farmers looking to collect samples once a week can expect to send in around 15 samples.
In years when budgets are tight, Johnston said practices such as tissue sampling are more beneficial than ever.
“You might find you’re spending more money than you need to on the wrong products,” Johnston said.
“Tissue samples will really help you identify which nutrient is bringing the most return on investment and which nutrients are affecting yield the most. Then, we can reallocate our fertilizer budget to make sure we’re getting the most important nutrition into the plant at the appropriate time.”
While tissue sampling may seem simple, implementing a protocol that leads to beneficial findings can be a big undertaking.
“It’s not anything you can go into just willy-nilly,” Kaiser said. “A grower really needs to make up a good plan in terms of what to sample and when to sample.”
It may seem easy to overlook planned sample collections when larger issues arise, but to get accurate data, sampling should be a priority.
“You have to be diligent, and you have to be self-motivated that your priority is to get these tissue samples,” Johnston said.
“It’s really easy to fall into that temptation to skip a week here and there, but you just can’t, because we’re trying to identify nutrient flow on your farm to help address fertility issues and make more yield.”
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