How measuring seed-available moisture ensures optimum planting depth

It’s a no-brainer investment for touchy crops – technology that ensures better rates of germination thanks to a optimum planting depth, where there is sufficient soil moisture.

Crops like corn, explains Josh Unruh, who farms 3,000 acres in southeastern Mississippi, are planted early in that region, around the first of April, during which moisture is not an issue. Also, young corn seedlings, on emergence from the seed, have a robust ability to push down through soil to find moisture as needed. So, it’s not a sensitive crop in terms of optimum planting depth.

Lot of challenges with cotton

But cotton for example, planted about a month later with little push-down ability, is another story. Like other farmers of cotton, Unruh has had a lot of challenges with emergence, often having to replant some of his acreage. That’s why he started using tandem planter attachments called SmartFirmer and SmartDepth in 2021.

Using them together, farmers get real-time seed-available moisture measurement with instantaneous automatic corresponding adjustment of planter depth.

Bryce Baker, marketing manager at the company that makes them, Precision Planting, notes that besides measuring seed-available moisture in real time, SmartFirmer also gives reading of the seed bed in terms of temperature, furrow wall uniformity – whether the sidewall is caving or cracking – and soil organic matter changes as well.

With corn we get a 6-8 bushel per acre increase

Unruh explains that a neighbouring farmer with whom he grew up had beta tested the attachments and that’s what convinced him to try the system last year. “It’s been a vital tool with cotton, but I do use it with corn as well,” he says. “One of my two planters has SmartDepth, SmartFirmer and an attachment called FurrowForce which closes the furrow, and compared to the other planter without these, with corn we get a 6-8 bushel per acre increase. And the seed meters and singulation placing to get the right plant stand population, these planter attachments also are what pays off with corn.”

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Three different soil types

The fact that Unruh as three different soil types on his land also really makes SmartDepth useful with cotton. Some soils hold onto moisture and other sandier types not nearly as much.

Unruh adds that “cotton doesn’t germinate well when it’s planted more than about one inch down, so I like the option to see your minimum and maximum planting depth. That is, if I don’t set a maximum pllanting depth, SmartFirmer will direct SmartDepth to plant too deep in some soils when it’s dry and you won’t get good germination. I’ve found that setting depth is very reliable.”

SmartFirmer also allows you to pick an optimum depth (1 inch for example, with leeway of one quarter inch up and down).

You have to put the time in, but the peace of mind is priceless

At the same time, Unruh cautions that there’s a learning curve. “It’s not a system you can just put in and turn your back on, you have to put the time in, but the peace of mind is priceless,” he says. “It’s not uncommon for us to have to re-plant cotton but we’ve never had to replant since we got it. I really like the customization. I may be different in terms of maximum and minimum planting depth than another farmer down the road, but I can set it how I want it, and from my experience on my farm. It takes only about 30-45 minutes to set it up.”

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Return on investment

ROI depends on spring planting conditions but Unruh believes there are definitely scenarios where you could pay it back in one year. Avoiding re-plant alone (fuel, seed costs and time saved) is significant.

Normal planting time for cotton is also shorter, with fuel and time savings there as well. Unruh says this spring had little moisture and with the two planters starting out together (one helmed by Unruh and one his employee), his employee was out checking soil moisture with a probe all the time and Unruh finished out half a day ahead of him – and also got a better plant stand.

Availability of SmartFirmer and SmartDepth

SmartFirmer and SmartDepth units have so far been sold in the US, Europe and South America, and the cost for each unit of either type is about $675 USD.

To use one of these systems or both of them, a ‘20l20’ Precision Planting cab monitor system is required, along with Precision Planting control modules on every planter row. The ‘20l20’ monitor and SmartFirmer were available in limited quantities in 2022, with more units expected to be available in 2023.

Unruh has asked Precision Planting to create the option for automatic mapping in terms of planting depth. This would be very useful for him because he has areas of his acreage where he irrigates and doesn’t irrigate. It’s really hard to track this manually as he’s constantly criss-crossing these zones.