Preventing Soil Erosion with Grass-fed Beef
July 12, 2023
Better food starts with better soil. As President Franklin D. Roosevelt famously said,
"The nation that destroys its soil, destroys itself."
He couldn't be more right. That's why we choose to manage our pastures in a way that protects, enhances, and builds soil. Because if we lose the soil, we lose our ability to grow food.
What threatens soil?
1. Erosion is a big one. Whether from wind or rain, erosion literally takes topsoil and all of its nutrients away from the land.
2. Chemicals. Soil is more than what it appears. It's not just dirt (broken down rock particles, minerals, organic matter).....it's alive and teeming with microorganisms that help make those nutrients available for plants and other animals to use. Pesticides and other synthetic chemicals can destroy these microecosystems.
3. Nutrient Loss. If you think of soil as a "bank" of nutrients, to keep things plentiful you must "input" for all of your "exports". If you only harvest nutrients from a field or pasture (in the form of hay, crops, etc.) and never give any back, you have depleted the soil of its nutrition and removed the ability for it to support plants and other life forms.
4. Compaction. The more you walk, drive, or pressurize the soil, the more compact it will be, therefore losing its air pockets and ability to support plant growth and absorb water.
How to Protect Soil with Livestock
We have an array of different practices we use to protect and even build the soil health. Each of them has a different way that they help protect against the 4 threats to soil health.
Those tools are:
1. Cover Crops. Our winter area for the cattle gets pretty beat up every year, so in the summer, we plant it with cover crops to try and help protect it. We use a "no till drill" to plant the seeds so we minimize any soil disturbance and underground compaction normally caused by tilling.
Cover crops are a diverse mix of annual plants that are fast growing to help "cover" the soil for summer.
Deep rooted plants in the mix (like turnips) help to break up compaction from the winter, while other grasses with shallow, fibrous roots help hold the soil in place so it doesn't erode away in the rain or wind.
Like the perennial pastures described next, cover crops help water soak into the ground, too, instead of running off the surface.
2. Perennial Pastures. The majority of our grazing lands are perennial pastures. This means that the plants grow back every year, without us needing to plant more. Their deep, healthy root sytems prevent erosion by holding the soil in place year-round.
The different types of perennial plants and root structures reach different depths and uptake different nutrients to keep the "soil bank" stocked with essential nutrients like potassium, phosphorous, nitrogen, calcium, magnesium, etc..
As the roots grow, expand, and die back from year to year, they create a loose structure in the soil, resembling a "crumbly" texture. Those gaps provide air and oxygen to the microorganisms living in the soil.
It also provides space for new plant roots to easily grow. It's the difference between you trying to plant a flower in a compacted ground space or a nice potting mix. The potting mix is much easier for you to work, and for the plant roots to navigate too, because it has way more air space in it.
Perennial plants make it easier for the soil to absorb water, too. All of the vegetation catches the water above ground and helps it slowly soak down into the ground, instead of running off the soil surface like it would without any plant cover.
3. Rotational Grazing. This is the key piece to soil health. Plants and soil need animals to complete the cycle!
Animals eat the plants and deposit their waste, which fertilizes the ground, forces plant diversity (by spreading seeds, selecting certain plants over others, etc.), and stimulates new plant growth by grazing.
The key word here, though, is "rotational".
When livestock enter the field, they walk around and eat. If left in the same spot for a long time, they will eat all of the plants they want, walk over the same area repeatedly, and in turn, damage the soil with compaction and erosion.
However, when the animals are moved in a controlled pattern across the entire field, one section at a time (as seen above), they eat just enough of the plant to stimulate it to put down more roots and grow back. They also aren't standing around in the same spot long enough to compact it.
The animals apply their own fertilizer, as well, in a small, evenly spread quantity at a rate that the insects and microbes can easily break down into nutrients that feeds the soil and help the plants grow back even better.
If more fertilizer or manure is applied to a field than the soil microorganisms can actually break down, the excess nutrients (and bacteria in the case of manure....like e. coli) will run off the soil surface and become pollution, most often in waterways.
The photo above is of Elli and Bryce checking out a paddock that was grazed 1 day before. Elli is looking for dung beetles and other insects in the manure to see them breaking it down into soil already. You can see that for the 70 cattle that were in this space just the day before, there is no large swash of manure on the field.
4. Minimize Disturbance. We rarely use heavy equipment in any of our operations to help protect the soil structure. Heavy tractors and repeated driving can cause compaction, which leaves no air space in the soil for roots to grow in or water to seep into, leaving the soil surface hard and difficult for plants to grow in.
The cattle are heavy, but they disperse their weight amongst their 4 hooves and don't tread the exact same spots all day every day, therefore, minimizing damage to the soils. The weight distribution of the henhouse acts similarly, minimally disturbing the soil structure.
When we do drive out to the field, we take the same path every time so we are constricting our damage to a single space, instead of the whole field.
Does it work?
Of course, we never use chemicals or synthetics on our fields of any kind, so we protect our soil in that way from the start.
As for soil erosion and compaction, we put our soils to the test with the NRCS rain simulator machine. They took a few samples from our own pastures and others from a conventional field and applied rain to see what would happen.
The water in the jars hanging just below the soil/plant samples represents groundwater, or water that has safely infiltrated into the soil thanks to the plant roots. The jars on the ground are holding whatever water and soil eroded during the rainfall.
As you can guess, our pasture samples are the ones with a LOT of grass, a LOT of water infiltration in the hanging jars, and NO runoff in the jars on the ground, which is exactly what should happen when the soil is managed properly.
You can see that the jars on the ground with a lot of soil and water in them came from conventionally managed fields that don't have perennial plants or rotational grazing as part of their management practices.
What about nutrient depletion?
By the time the cattle return to a grazing spot, the manure is wholly incorporated back into the soil, leaving no sign that the cattle were ever there before.
The ability of the microorganisms to break down those nutrients so quickly and make them available to the growing plants is strong indication that the nutrients are all being cycled appropriately, and no nutrients are being depleted from the soil.
Of course, testing our hay samples and soil from time to time, just to be sure, confirms that our practices are actually building top soil, not taking it away.
But we'll talk more about nutrition next week, when we explain how the way our animals are raised results in better food and a better life.
Until then, leave us any comments or questions in the box below and we'll do our best to answer them. Thanks!
You can see a video example of the Wisconsin NRCS rainfall simulator in action, here. It's not from our farm, but the same principles apply.