Soil needs to breath. It loses productivity when sealed with a layer of hardpan or a buildup of mulch on the surface to block the infiltration of air and water.
Cattle producers have long realized that pasture soil becomes dry and hard when it has been compacted by a concentration of animal hoofs and has had its surface sealed by a thick mat of organic matter. Water runs off instead of soaking down into the root zones, and air fails to reach soil microbes down within the soil.
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Year after year, the pasture becomes progressively less productive.
However, it’s no longer just a cattle producer’s problem. Veteran zero-till farmers have found the same issues in their long-term no-till fields, said agronomist David Benjamin of RanchWorx, which designs and builds soil aerators for sale around the world.
Benjamin, who works in Okotoks, Alta., said that when the company started building soil aerators 44 years ago, they were intended to be used in pasture and hayland renovation. The concept of zero-till cropping hadn’t even hit yet.
“We’ve become accustomed to walking an old pasture and seeing a condition known as root bound soil,” he said.
“It’s caused partially by hooves of cattle. Researchers say there’s more soil compaction from the hooves of a cow than there is from tires on our big tractors.”
The similarities between pastures and zero-till fields are becoming more evident, he added.
A number of inter-related factors prevent roots from going deep in their water quest. Compacted soil is too strong of a barrier to allow the roots to migrate, and there’s very little water in the lower zones anyway because it can’t infiltrate. As well, taproots don’t make the effort to search deeper because they sense that there’s no water down there, As a result, the roots interlink into a tight mat just below the surface.
RanchWorx blades carry a lifetime warranty against breakage. | David Benjamin photo
Despite countless studies that validate the benefits of soil aeration in pastures and hayland, Benjamin said some cattle producers are still reluctant to take the plunge.
“Guys tell me, ‘my grandfather owned that land a hundred years ago and he told us to never touch it. If we do, we’re going to bring up rocks and start all kinds of erosion and other problems,’ ” he said.
“But the RanchWorx doesn’t do those things. It’s not like deep tillage or ripping. You’re not bringing up boulders or exposing the soil to erosion. The work is performed by sharp six-inch-wide blades welded to the roller. Slices in the soil surface are only six inches across and six inches deep.
“The big thing is that it fractures the soil down to a depth of 24 inches. It alleviates any hardpan or compaction so water can finally get down into the soil.”
Gravity brings water deep into the soil and the roots chase after it.
Benjamin said the impact on the root system is the same in zero-till field crops and forage crops. The plant puts down taproots that are deeper and stronger so it accesses more water and nutrients.
Not only does the aeration process allow water to flow into the soil, but it also incorporates organic matter.
Benjamin said nutrient re-cycling is stymied in pastures, hayland and zero till fields because organic matter lies on the surface. Many nutrients are lost to the atmosphere as it decomposes. A soil aerator works some of that organic matter into the soil so the nutrients feed the crop.
“Soil aerators take an excessive amount of physical abuse,” Benjamin said.
While other manufacturers use a spike or a tine to punch holes in the soil surface, RanchWorx uses a blade.
“We have enough confidence in the strength and integrity of our blades that we warranty them for life against breakage. We can’t warranty them for normal wear and tear, but if a blade breaks, we replace it free of charge. We have a special process for welding on new blades so they remain in place.”
Benjamin said the frequency of aerating a field or a pasture de-pends on soil conditions.
It also depends on annual rainfall. He said it’s best to aerate just before rain if possible. The other strategy is to aerate just before winter so you’ll have water penetration from snow melt and frost penetration.
“Custom aeration is a good way to offset the investment in a machine,” he said. “It’s not a machine that you’ll use full time on your own farm. Rather than let it sit idle, there are opportunities to do custom work for other farmers.
“I was a hay producer before I started with RanchWorx. I ended up buying two of these machines because one was always rented out. I couldn’t get my own work done, so I had to buy a second unit.”
Some RanchWorx models are designed specifically for brush clearing. Some are single drum and others are tandem drum units. He said once the pulling tractor has knocked down the biggest trees and brush clumps, the aerator mulches the wood and slices into the root balls. The blades incorporates the wood and breaks up the root system, he added.
“When you’re talking about brush clearing, you used to have only two options,” he said.
“You can spend a lot of money and spray it out to kill the trees, or take a dozer or an excavator to dig it all up and pile it and eventually burn it.
“But now people are realizing that these aerators are a viable third option. If you have a tractor that can drive through it, the aerator will do the rest. And we’re seeing more 4×4 tractors now with blades on the front, so this is a logical third option. A lot of guys already own those blades, so all they need is the aerator to pull behind.”
RanchWorx has a wide variety of soil aerator types, ranging in price from $15,000 to $100,000. The most common units sold on the Canadian Prairies are the SB models ranging from $20,000 for an eight-foot drum up to $40,000 for a 16-foot drum.
“Here’s an interesting fact to consider,” Benjamin said. “Every year, we’re selling more soil aerators to the zero-till guys who are a hundred miles from the nearest pasture.”
