Rest, Roots, and Biology Combat Compaction in Louisiana
This article is reprinted with permission from Graze magazine. To request a free sample, call 608-455-3311 or email sample@grazeonline.com. To subscribe, visit https://www.grazeonline.com/subscribe.
Written by Ted Miller, Dairy Grazier in Baskin, Louisiana
Question: "How do you handle compaction?"
"I don’t honestly know to what degree compaction is impacting our soils and potential pasture forage yield. That being the case, I will discuss interactions I’ve had with the topic in the past, what I’ve observed, and how I think (or hope) compaction is or isn’t affecting pasture performance.
Potential sources of compaction would obviously be from large groups of cattle grazing in high density in a given location at a particular time. It’s not uncommon for us to run 50,000 to 100,000 lbs. of cattle per acre at times in order to control pasture covers. We will also typically do this without regard for soil moisture conditions. We often get large rainfall events that deliver multiple inches of rain at one time, so we can suddenly find ourselves with saturated soils.
One other potential major source of compaction would be wheel traffic from feeding equipment. We feed all of our baleage unrolled on dormant bermudagrass pastures during the winter. Winters can be extremely wet here at times and, just like the grazing events, the unrolling and hoof traffic is occurring no matter how saturated the ground. For these reasons I would think the potential for soil compaction definitely exists.
What I’ve observed over the years doesn’t necessarily indicate we are experiencing significant yield loss due to compaction. In the spring, our most productive pastures with higher levels of diversity — often with no fertilizer application — are the ones we’ve just wintered on. This is probably due to all the fertility and organic matter applied to these fields over the previous few months.
Because we don’t do any tillage or subsoiling, I feel our most effective weapons against soil compaction are the roots of annual grasses along with long rest periods between grazing events. Each year, every acre on the farm receives a cool season annual planting. Approximately two-thirds of the pastures are drilled with oats and overseeded with annual ryegrass in the fall. The other third is overseeded with ryegrass in early February as we approach the end of winter feeding.
As we move through spring we try to let these grasses fully mature, thus developing as deep a root system as possible. By maintaining a strong clover component in the stands we can continue to get adequate performance from late-lactation cows despite the maturing winter annuals. By later in the spring, the majority of the ryegrass ends up being trampled into the ground rather than consumed, providing excellent conditions for the emerging bermudagrass to grow through.
The longer I’ve grazed cattle, the bigger believer I’ve become in the importance of long rest periods. We like to move from 25-28 day rests at green-up to a 35-40 rest period by late spring/early summer. I believe it’s only when the winter annual grasses can fully complete their life cycle that we can benefit from the deep root systems they are capable of growing. That root system decays during the summer, leaving tremendous voids in the soil along with considerable organic matter breakdown that releases nitrogen for the summer grass crop.
It may be that the weathered nature of our Delta soils help us avoid compaction issues as well. These soil particles are worn smooth and round, making them fairly permeable to water. It’s not uncommon to be able to stick a three-eighth inch fiberglass fence post 12 inches or more into saturated ground. But when that soil dries out, it can become extremely hard. A couple of years ago we hosted a pasture condition scoring workshop on the farm. I found the scoring criteria used to measure soil conditions interesting. We compared soil permeability between areas where cattle had access to with areas they did not, such as under fencelines. It did seem that the soil was somewhat more permeable where cattle access was restricted.
After a lot of observation and little to no quantifiable data, I sometimes wonder how much forage yield loss we are experiencing due to compaction. And if there are losses, how could we mitigate them in an outdoor cattle housing system? I think that ultimately a biological approach to minimizing negative effects from compaction may be best."
Comments