Soil & Water
SOIL, WATER & GRAZING
The connection between grazing, soil health, and healthy food has never been clearer. Human health ultimately depends on healthy soil. Now soil scientists have documented that rotational grazing improves soil fertility and water retention.
So how do Big Picture Beef's methods reflect the latest findings from soil science? Our basic pasture management goals are simple: (1) to establish deep-rooted pasture plants, and (2) to foster abundant life in the soil food web. Here is why and how we do both.
INCREASING FERTILITY BY GRAZING
Soil micro-organisms are critical to plant health - and to human health, through our diet. By fostering beneficial soil fungi and bacteria in our pastures, we increase the depth of fertile topsoil. Mycorrhizal fungi, which are in and on and around the deep pasture roots, have hyphae that can extend several yards into the soil.
These long filaments allow for a two-way flow that (1) takes a portion of the carbon from pasture plants and stores it deep in the ground as humus, and (2) transports soil nutrients to the pasture plants.
The fungi, as transporters of minerals, can be a critical source of nutrients for the plants. These nutrients are phosphorous, organic nitrogen, and calcium, as well as trace elements such as zinc, boron, and copper, and plant growth-stimulating substances.
In fact, if poor management causes the carbon supply to become limited by the loss of this two-way transfer system, soil loses its physical, chemical, and biological functions, which in turn causes mineral depletion in food. Scientists have noted that the loss of soil microbes in recent decades has caused a decline in nutrients in both crops and meat.
The following conventional agricultural practices have contributed to the destruction of natural systems that we rely on for nutritious food:
- soil disturbance, such as plowing,
- application of nitrogen or water-soluble phosphorous, and
- application of herbicides and pesticides that kill essential soil microbes.
What can replace the environmentally destructive practices that have become the norm? Big Picture Beef uses regenerative approaches that have been pioneered by progressive agriculturalists in the United States and overseas. Rotational grazing (sometimes known as multi-paddock grazing) is a key practice for fostering the soil food web on which our health depends.
We move our cattle in a rotation from paddock to paddock, with new paddocks being created simply by moving flexible fencing. Eventually the cattle are cycled back to the original paddock after that area has had sufficient rest to regrow the grass until it’s tall again. This repeated rest and regrowth of the paddock fosters deep roots, which are important for creating humus and making soil minerals available to the cattle via fungi and associative bacteria.
Studies show that rotational grazing produces more herbage than conventional grazing or ungrazed land, and that this translates into greater weight gain of livestock that are grazed in a rotation rather than conventional grazing.
ADDITIONAL WAYS THAT WE INCREASE FERTILITY
Other sources of fertility are (1) manure, which the cattle spread evenly over the land, and which supplies microorganisms as well as soil nutrients, (2) weed residues and green manures that decompose, (3) root material that the plants shed when they are grazed, in order to re-establish equilibrium between the roots and the leaves, and (4) the remains of dead mycorrhizal fungi and bacteria.
Dung beetles have a unique role in the soil food web. Found on every continent except Antarctica, they quickly remove large animal manure from the surface and bury it, using it subsequently for food and for incubating their eggs.
INCREASING WATER RETENTION BY GRAZING
Rotational grazing is a critical protection against drought and erosion because it increases soil carbon. Without a carbon “sponge,” rain will not penetrate soil; instead the water runs off, causing the soil to erode. While the Northeast generally has adequate rainfall on a yearly basis, soil carbon is necessary to keep grass green and growing during dry spells. Carbon allows rainwater to infiltrate soil and remain to protect against drought and erosion. Sequestering carbon in the ground is also an essential strategy for stabilizing the climate.
Just as soil microbes are key to fertility, they are also key to water retention. The Glomerales fungi colonize plant roots and make a protective waxy coat called glomalin that stores both water and carbon.
Glomalin improves water infiltration and water retention in the soil and keeps soil carbon from escaping to the atmosphere. A 2013 study of three cropland scenarios and three grazing scenarios found that the highest concentration of glomalin is in native grassland pastures managed by rotational grazing.
Glomalin also glues together silt, sand, or clay soil particles, forming large granules or aggregates that improve soil condition, providing what is commonly known as “tilth.” Aggregates protect soils from eroding winds and water. Previously plowing was thought to increase tilth, but now it is understood that soil disruption contributes to soil compaction, whereas no-till seeding increases soil glomalin - and thereby protects against drought.
The NRCS (Natural Resources Conservation Service) made this 6-minute video below to demonstrate the dramatic difference between fields that are managed with rotational grazing and minimum soil disturbance and fields grazed all season or planted with crops:
Once a piece of land has become healthy and fertile from good grazing and pasture managment, it can be used for cropland in rotation with pasture for livestock; crop yields will be more abundant than could be expected on land that has not been managed by rotational grazing.