Probes reveal soil moisture’s many secrets
Soil moisture probes have been around for a long time, but they remain one of those mysterious agricultural instruments that only a small handful of people attempt to understand or use.
“Part of the problem is people don’t trust the information,” says Ryan Hutchison of South Country Equipment in Saskatchewan.
He was at Crop Connect 2019 in Winnipeg to give a presentation called Crop Intelligence — Trusting the Data. Hutchison, who heads up the company’s CropIntel program, said soil moisture probes can provide good management information, but only if you know how to use it. He said the probe helps understand soil moisture from the perspective of the crop’s root system.
“You need to know how much moisture you have, but just as important, you need to know if it’s at the bottom of the root zone or shallow near the surface. And agronomically, you need to know what an agronomist can do with that information in terms of yield management.”
Hutchison said moisture probes allow agronomists to be proactive in managing crops in-season. Before probes came along, the typical scenario was to gather all the information, do your due diligence in putting together a variable rate prescription, apply it and then wait until harvest to measure the results. There was very little in-season in-crop management.
“Soil moisture probes give us new timely information that we can act on in the growing season. Knowing how much moisture we have at each depth lets us make educated decisions while the crop is growing,” he said.
“You may find you should add nutrition or make a fungicide application. You may find you don’t have enough subsoil moisture for a high yield, so you skip the in-crop (nitrogen).”
Hutchison compares the moisture probe to the GreenSeeker, in the sense that it provides in-season information about the crop. He says the integration of these sources of real time information lets a producer fine tune the crop to meet full potential.
Hutchison said the real-time data can be fascinating. Some clients with radio remote units check their stations up to 160 times a month, especially in June. That is the one time of the year that a farmer can do the most to bolster his crops through crop protection products and extra nutrition.
The moisture probe is only one device in a suite of instrumentation designed to monitor crop behaviour real time. Depending on how much information a producer needs, the cost for a station runs from $3,000 to $10,000. The full-house station gives producers plenty to think about:
- soil moisture at 10, 20, 30, 50, 100 centimetres
- solar radiation
- growing degree days
- air temperature
- soil temperature
- leaf wetness
- wind speed and direction
“An example of how the moisture probe can make money plays out like we had last spring near Regina,” he said.
“Shortly before seeding, we had good subsoil moisture, but the top five to 10 cm of soil was quite dry. The crop needs moisture. It has to germinate and emerge. It’s got to set its roots and get after the moisture down below, the moisture is there. If you’re sure there’s good moisture below, maybe you take a gamble and go for high yield.
“If the crop gets a little rain and gets off to a good start, it’ll be off to the races chasing moisture down below.
“The other scenario might be that the top five to 10 cm has good moisture, but it’s bone dry down below. Do you pile on the inputs, or maybe back off and go for a low input year?
The fall, after harvest, is the other time the moisture probes earn their keep. Once the crop is off, it’s a good idea to see how much moisture is left in the soil, all the way down to the bottom of the root zone. Reserve moisture may have a lot to do with your winter planning for the next year.
“These moisture probes have been around for about 20 years,” he said.
“It’s not new technology that has to be tested in five years. We know moisture probes work. But if you’re not going to trust the information, then it’s not worth it to the producer to invest in the program. There’s no miracles created from equipment, that’s for sure., but moisture probes work.”
CropIntel app collects Field Connect data:
- Field Connect documents soil moisture down to 100 centimetres, rainfall, air temperature, humidity, leaf wetness, solar radiation and growing degree days. This data is generated by a string of stations strategically located in the client’s fields. Hutchison said his team uses all available maps and topographic data to place each station in a “normal” location where it will give them data that should be typical of the whole field.
- CropIntel is South Country’s app that collects Field Connect data and calculates crop available water and water driven yield potential in dryland farming. CropIntel processes this data to assist farmers in making agronomic decisions and optimize return on investment.
- It interprets weather station data by factoring crop available moisture, accumulative rainfall and expected precipitation to model yield potential throughout the growing season. This allows a farmer to make real time decisions on their farm with confidence.