More sensors for planters

A seed trench firmer with sensors takes readings every eighth of an inch across the field

Wayne Vitek plants soybeans with a Smart Firmer on the planter.
Reading Time: 4 minutes

As Wayne Vitek drove across a field near Mitchell’s Bay planting soybeans recently, a group of sensors took 200 readings per second at the soil level.

A Smart Firmer was in place of where a Keaton Seed firmer might have been, flattening the soil over the seed trench, but also collecting data on soil organic matter, soil moisture in the furrow, soil temperature and a measure of the amount of furrow residue.

Vitek is a precision support technician and farm operator at Devolder Farms, which farms close to 1,000 acres of land in the area, but also sells grain storage equipment and planter technology.

Nick Zwambag, crop solutions specialist at Devolder Farms, said Precision Plant dealers, like Devolder Farms, each got a limited number of the Smart Firmers. He was able to sell all of the ones he got and had a waiting list for more.

The Smart Firmers cost about $600 each, but need a minimum of three per planter. For planters with more than eight rows, a firmer is needed for each four rows. A 24-row planter would need six.

There are four sensors on the Smart Firmer. photo: John Greig

On Bob Devolder’s planter, which plants 15 rows at 23 inches spacing per row, they were testing another new technology, a FurrowJet, which combines the seed firmer with the ability to put place liquid fertilizer in furrow.

What do you do with the data?

Organic matter

The Smart Firmer builds a map for organic matter, which is the major piece of information that farmers are looking for from the set of sensors. If a planter is equipped to do variable rate seeding, the system can make those variable rate decisions on-the-fly based on organic matter. Higher organic matter soils should be able to handle higher seed populations.

Nick Zwambag is the crop solutions specialist at Devolder Farms. photo: John Greig

“It’s a quick way to get into variable-rate seeding,” said Zwambag. No yield maps or satellite images are needed, although Zwambag says more layers of information are better.

“We can say at higher than five per cent organic matter, give me 36,000 population for corn. Between four and five give me 34,000.”

The system extrapolates organic matter for the rows without the sensors. For other data points, such as moisture and temperature, it just leaves the other rows blank on the maps.

The on-the-go organic matter sensing can also mean starter fertilizer can be varied at planting.

There’s still more to learn about how exactly to match changes in population with changes in starter fertilizer application, especially when the bigger slug of nitrogen is often put on the field later as a sidedress. The organic matter mapping system may be more valuable for that later application of nitrogen. Varying nitrogen using soil organic matter could pay for the Smart Firmers in a year or two depending on the number of corn acres on a farm.

Zwambag has been surprised about how little variability in organic matter there was in the Devolder Farms area. Some fields have fairly consistent organic matter and others do not. In the field where Vitek was planting, a sandy patch in the field was just above two per cent and an area near a ditch was about 3.5 per cent.


The amount of variability of soil temperature throughout the day was one of the lessons that surprised Zwambag.

“We started one field one morning and it was saying it was 40 F to 45 F and by 10 o’clock on this particular farm, and it’s a black sand, it was like 60 degrees. Later in the day, as soon as the sun went down, it came down,” he said.

The challenge is what to do with temperature information. If the soil is fit, a planter isn’t going to stop because it’s getting cooler in the evening. If you are planting in April would you stop? Maybe.

Where it could be valuable is if a farmer knows hybrids well enough to know which emerges better at cooler temperatures.

Clean furrow

The clean furrow function that measures residue is an on-the-go measure. Row cleaners can be set to be more aggressive when there’s more residue, and can be backed off when there is not.

Vitek said the function came in handy while planting a former wheat field that experienced some of the heavy rains this spring that washed residues into piles.

Moisture measurement

If ground conditions are fit, the moisture measurement isn’t likely to be helpful as the planter moves across the field. Zwambag says farmers in other parts of North America sometimes plant into very dry conditions and that’s where planters may be adjusted so that the seed is into soil with moisture. The measurement is in a percentage and is the chance of a seed emerging in three days with the moisture available. There could be some times that it would help to know changes in moisture during the day.

More Smart Firmers will be available this summer when production moves beyond initial release.

About the author


John Greig

John Greig has spent his career in agriculture journalism and communications. He lives on a farm near Ailsa Craig, Ontario. Contact John at [email protected] or follow him on Twitter @jgreig



Stories from our other publications