There are lots of reasons why the traffic patterns of farm equipment can overlap in a field. The field could be an odd shape, there may be a stream cutting across it, or large obstacles like hydro towers have to be driven around.
If this happens while you’re applying fertilizer, nutrients can build up in overlap areas over time — something that could have important consequences for farm nutrient management.
Steve Crittenden, an Agriculture and Agri-Food Canada research scientist based in Brandon, Man., conducted a study examining how landscape features, such as water bodies, roadways, electrical towers, or odd or non-symmetric field shapes may force complex driving patterns for farm equipment that create uneven nutrient applications and excess applications in overlap areas.
Read Also
Good news, bad news for fungicides meant to fight stem rot in canola
A report shows overall insensitivity of sclerotinia to three fungicide groups hasn’t changed in a big way between 2010 and 2024 — but shows some sclerotinia populations have been discovered with elevated insensitivity to all three.
Soil samples were taken from farmers’ fields in Alberta, Saskatchewan, Manitoba and Ontario for the study, which was published in the Canadian Journal of Soil Science in August 2020.
The research shows in those farms surveyed, soil nitrate concentrations were 60 per cent higher and phosphorus concentrations were 23 per cent higher in the zero- to 15-centimetre depth in overlapping areas compared with non-overlapping areas. Soil pH was also 0.5 units greater in the overlapping areas.
“We were interested in the accumulation of nutrients in overlapping areas because we felt it was an overlooked aspect of nutrient management,” says Crittenden.
“Producers know their fields and they know how many times they drive over the same spot twice,” he adds. “What we wanted to do with this research was quantify the amount of nutrients that are left over in those overlapping areas and try to demonstrate the extent to which they’re leaving nutrients there.”
Crittenden’s research suggests there’s generally more overlap in seed, fertilizer and pesticide applications in smaller field sizes and when fields are irregularly shaped. The amount of overlap will also depend on how many obstacles there are in a field and on the size of the farm equipment.
Crittenden says a key takeaway from his study is farmers and crop consultants should avoid soil sampling in overlap areas since they do not represent typical field conditions.
He adds overapplying nutrients is not only a waste of money for farmers but can also lead to potential crop losses due to lodging. There are environmental implications as well since excess nutrient applications can result in leaching, runoff and greenhouse gas emissions.
Lag in technology adoption
Crittenden’s study states technologies like GPS guidance systems and automatic section control, which can reduce excess applications of seed, fertilizer or other inputs by shutting off parts of equipment where application to land has already occurred, can improve nutrient use efficiency by reducing field overlap and gaps.
However, the study also indicates there may be a lag in adoption among farmers. It refers to a survey of western Canadian producers in 2016 that showed while automatic section control was available on 73 per cent of respondents’ equipment, only 36 per cent used it for fertilizer applications (compared with 26 per cent for seeding and 70 per cent for spraying operations).
Adam Gurr’s farm near Brandon, Man., was one of those surveyed in Crittenden’s study. Gurr recalls the survey took place about 10 years ago when he was starting to implement automatic section control when seeding and fertilizing his fields.
“We invested in that technology … because we were running an 80-foot drill. You can imagine what kind of overlap (we had),” Gurr says, adding the Seed Hawk air drill he purchased has automatic section control for 10-foot sections, which helps to minimize field overlap.
Gurr views automatic section control as a sound investment that pays for itself through seed and fertilizer savings, something he believes most farmers can get behind.
“It just makes sense when you’re upgrading your equipment, if overlap is a concern for you,” he says.
Automatic section control technology is much more widely available these days, Gurr notes. “You can get it on pretty much anything,” he says, adding he knows producers running anhydrous ammonia rigs that have them set up with sectional control.
Gurr says with more seeders being produced with built-in section control these days, farmers have more options for increasing their nutrient use efficiency. He also thinks they’ve been around for long enough that farmers looking for a good price should be able to find something they like on the used equipment market.
