Probe deep into your soil to solve farm’s moisture mystery

Soil probe expert says you can use soil probes and their data to your farm’s financial advantage

 Guy Ash, of Pessl Instruments, 
demonstrates how a soil probe can 
augment weather station data.

Looking around at the wet conditions, at first glance you could think our moisture levels are more than adequately stocked going into the 2020 crop year. Unfortunately looks can be deceiving, and the same goes when looking at your soil profile.

When it comes time to plan your planting timing and strategy, knowing the actual moisture content can lead to better crops and more money for you come harvest.

Whether it’s snow, sleet, hail or rain, looking around the Prairies right now we see an abundance of moisture causing harvest headaches throughout the industry. While there’s more than enough to go around right now, those moisture levels will be dramatically different next spring.

“Just because you kick some soil around and guess that you have enough moisture, you really have no idea what’s actually going on until you dig down and take a look,” Guy Ash told the Co-operator recently.

Ash is global training manager with Pessl Instruments, and a well-known expert on soil probes and utilization of their data. I recently joined him on a tour at Kellburn Farms south of Winnipeg, where he showed us two different soil probes being used in their test plots.

One of the moisture probes was a model from John Deere connected to a remote weather station from Metos, while the second was the Sentek Drill & Drop Triscan Probe from Pessl Instruments.

Slightly more advanced than a rain gauge and the boot test, the Sentek Drill & Drop probe uses capacitance-based technology to provide precision monitoring of temperature, water and salinity at multiple depths in a soil profile. It’s available in 10-cm, 30-cm, 60-cm, 90-cm and 120-cm lengths with sensors fixed at every 10-cm increment.

While the Drill & Drop provides you with salinity and temperature readings, the John Deere model only provides a moisture reading.

Ash says using a soil probe will give you a much more accurate reading of your soil’s moisture content. He said having this information be accurate is critical during the planting and fertilizing stages, and knowing your soil salinity and temperature helps you that much more.

“For example, with the low costs and the ability to collect data at the field level with sensors for moisture, temperature and volumetric ion content (VIC) every 10 centimetres (cm) down to a depth of 120 cm in 15-minute time steps, soil type specific data can be collected and translated into exactly where you are at in terms of soil moisture in a water-driven crop yield and provide a very good answer to a particular problem, such as nutrition. If you know you only have five inches of stored water versus nine inches of stored water in a different soil profile, you are going to manage nutrients and the crop differently.”

He added that testing in as many points as possible throughout the field will help plan for different areas of the field, and explained how this information can work with your other farm data to inform decisions and maximize the potential for a better yield.

“You’ve also got remote weather stations that you can use to check the real-time precipitation, humidity, wind speed, things like that. With so many new data utilization products coming out, as growers we’ve got access to a lot of information that we simply didn’t have before.”

As farm data collection continues to complicate as an issue, it seems (to me) that applications like this are where the information can be used to make practical farming decisions.

“It’s great when you think about it,” Ash said. “You’ve got the opportunity to go out in the fall and the spring to test, look at the numbers, and plan off of what you know, not what you might know.”

He says the numbers can vary dramatically within the same field, so having more details to make a better plan can only help.

“I can’t tell you the number of times we’ve done a test in one area of a field only to move and get completely different numbers only 40 to 50 feet away. Now multiply that by the size of your field, and you can start to see how certain parts of a field might need more attention than others.”

Hebert Grain Ventures, a 22,000-acre grain operation in southern Saskatchewan is one farm that’s turning its soil probe data directly into revenue.

Evan Shout, the Saskatchewan farm’s chief financial officer, was interviewed earlier this fall by Jennifer Blair of our sister publication the Alberta Farmer Express, and shared how soil probes helped one of their fields bring in some extra cash.

Last year, they bought soil moisture probes to maximize the limited moisture they were getting. At the time, the farm was sitting at about 40 per cent average rainfall, and every farm around them had parked their tractors due to the dry conditions. But based on the 30-year average, the probability of rain in the next month was quite high, and the new soil moisture probe showed there was still 11 inches of water in the ground.

“So what did we do? We went out and top dressed — 30 pounds of N across the farm. Everybody around us thought we were nuts,” said Shout.

Come harvest their check strips produced 11 bushels an acre less than the rest of the field, and protein levels jumped from 12 to 13.9 per cent, earning them a premium.

“That means we received $1.25 a bushel more just based on protein across the whole 80 bushels an acre, plus we achieved 11 bushels per acre more than we would have,” said Shout. “It cost us $15 for the N and $6 for the applicator fees — $21 an acre — but our net return was $162 an acre. It’s a seven-to-one return, all because of what the moisture probe told us.”

It may be one field on one farm in all of Canada, but the principles apply nonetheless.

About the author


Spencer Myers is a former reporter with Glacier FarmMedia and a graduate of the University of Manitoba’s Agriculture Diploma Program and Red River College’s Creative Communications program.



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