Grazing in Michiana
We have been soil testing our pastures and hay fields for many years and annually for the past 16 years. One of the many things I have learned from these tests is that the health of our soils improves every year.
On the soil tests, there is a line reporting the percent of organic matter in the soil. I like to think organic matter is the "life of the soil." To describe organic matter I found a helpful definition in a book titled: "Building Soils for Better Crops" by Fred Magdoff and Harold Van Es.
Quoting from the book, "Soil organic matter is the key to building and maintaining healthy soils because it has such great positive influences on essentially all soil properties—helping to grow healthier plants. It also plays a critical role in the water, nitrogen and carbon cycles. Organic matter consists mainly of the living organisms in the soil ("the living"), the fresh residue ("the dead") and the very well decomposed (or burned) material ("the very dead"). Each of these types of organic matter plays an important role in maintaining healthy soils."
From the soil tests we have seen it takes approximately five years in our rotational grazing operation to gain 1 percent organic matter. It also appears as though once we get to 6 percent organic matter in our soil types it levels out and doesn't seem to go much higher. The reason it is important for the soil to have a higher organic matter level is because it stores a large amount of carbon (greenhouse gases) in the soil.
Through the process of photosynthesis, plants take up the carbon dioxide in the air and use it to grow and through its root system it places carbon in the soil which adds to the organic matter. So the higher the organic matter level of the soil the more carbon it can hold. This helps use some of the greenhouse gases.
As the cows eat the grass and digest it, one of the by-products is a gas called methane, which is considered a greenhouse gas. There is concern by some that this causes an increase in greenhouse gases in the environment.
But, according to some research that was done at Michigan State University, they found that in a rotational grazing system where the organic matter is high that there is actually a "carbon sink"—the soil stores up more greenhouse gases (carbon) than the amount of methane the animals produce. So actually more greenhouse gases are being used up by the grass than what the animals produce on a rotational grazing farm.
So I have observed that as our soils get higher in organic matter the grasses and clovers grow better and the soil becomes richer and darker and as farmers know, that is a good thing. Another benefit is that the worm population has grown tremendously, and that helps with water infiltration and improves the soil and plants.
Another way that grazing helps the environment is by stopping soil erosion, which is a major problem of farming practices today. When a pasture has a lot of grass in it, the fibrous root system of grasses holds the soil in place and reduces the amount of runoff and keeps soil fertility on the farm. In a grass waterway on the farm, we have gained 12 or more inches of soil that has run off of neighboring fields in the last 10 years.
It appears as though greenhouse gases are increasing and causing some problems in our environment. For this reason I think it is important to think about using rotational grazing systems in our cattle operations and to consider using cover crops and crop rotation in our farming operations. It may require more work to manage grazing operations and use cover crops than to just run equipment across the land, but as we manage our farming operations we need to be thinking beyond today to preserving the health of the land for future generations of people.