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Soil mapping, photosynthetic technology combined to improve crop yields

by Wyoming Livestock Roundup

Worland – “I get to work with a lot of different crops and a lot of different crop advisors on technology and also on fertility and specialty products,” remarked Mike Griffel, technical service representative at J.R. Simplot Company, during WESTI Ag Days in Worland on Feb.19.

Griffel and his team have been focused on integrating precision agriculture with science and agronomy in the last few years to help producers make better decisions about the inputs they add to their fields.

“A lot of growers have the capability to collect field data, they just don’t. They don’t want to deal with it,” he explained. “Our program ties everything together, looking at the whole field and the whole 12-month cycle.”

The program is centered on “The Four R’s of Nutrient Stewardship,” a program that was developed by The Fertilizer Institute to reflect sustainability in agriculture.

“The Four R program was developed as a way for the fertilizer industry to help us steward ourselves and hold ourselves responsible. It involves putting the right inputs in at the right time, at the right rate and at the right place,” he described.

By ensuring proper application, producers get better value out of their nutrients, seeds, water and other resources while also being more environmentally sustainable.

Evaluating a field

When producers are preparing their fields and creating nutrient prescriptions, there are a number of ways to evaluate the land. Zones and grids are two common tools used to investigate the properties of an area.

“Zones are basically little fields within a field where we look at what’s different, based on soil texture, topography or other attributes,” noted Griffel.

A grid system uses samples at evenly spaced intervals to collect similar information.

“The grid system is utilized in a few very specific areas, but people typically shy away from it,” he said, explaining that a typical field has a high number of soil samples that can be very costly. “But, there’s a phenomenal data set when we go to look at future management.”


In a zone system, the number of zones depends on the individual field. They can be developed in a number of different ways, including a system based on electrical conductivity within the soil. After a map is created to represent variance in electrical conductivity, soil sampling is done to identify the properties of each area.

“We can make zones out of topography, photosynthesis or yield. Zones are living and breathing, so there are a lot of options. We also build a system to archive and track those zones as they evolve in the field,” he remarked.

Building the zones to match the needs of the producer is the most important part of the system, according to Griffel.

“The challenge is there is no set rule,” he stated. “We rely on specific geo-statistic algorithms. We reduce data into zones, and then we send it to the grower to find out if it makes sense.”


Soil samples are typically the first part of measuring field data, but Griffel and his team can also use photosynthesis to evaluate the needs of a crop.

“During the grow phase, satellite imagery is a big component of our program,” he commented, explaining how light wavelengths can be measured to evaluate plant health. “We measure photosynthesis and pick out patterns.”

By mapping patterns, areas with unhealthy plants can be identified and investigated further to improve management practices.

“We run statistics to identify what is significant. The beautiful thing is, we can quantify acres and rank fields as we process the data so agronomists and growers can immediately prioritize them,” he noted.

Combining data

The power of combining soil, photosynthesis and yield data is being able to produce a game plan, Griffel added.

Plant growth is limited by the availability of the scarcest resource, meaning that balance is an important part of field maintenance.

“With yield modeling, we can correlate soil samples, and we can identify which maps have the strongest relationships to yield data in our fields,” he explained.

In one example, combining data sets revealed that too much phosphorous was lowering yields in some areas of a particular field, leading to changes in fertilizer application at that operation the next year. Fewer inputs were added and plant health improved.

Applying technology

“This helps us understand what the limiting factor is,” Griffel continued. “Sometimes, we don’t see strong correlations, and the problem might be with water, seed or something that isn’t measured in the soil test, but we continue to aggregate the data.”

Griffel challenged producers to consider using technology in their own fields, asking their agronomists and crop advisors about options that fit best with their own operations.

“I don’t look at technology as an extra cost. We apply it to find savings and to get more out of our field,” he said.

Natasha Wheeler is editor of the Wyoming Livestock Roundup and can be contacted at

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