Five principles of soil health
As farmers and ranchers our livelihood depends on the soil. In fact, you could easily argue that all of our lives depend on the soil. It is the basis from which our nutrition is derived. Parker Creek Ranch, where I first developed my knowledge and skills, has been my personal experiment in soil health for a decade. When I moved back to the ranch in 2010, I arrived at a heavily degraded landscape. It had been plowed, sprayed with herbicides, fertilized with synthetics and overgrazed for more than 100 years. My great grandfather, Maurice Finger, told me stories when I was a kid of how he and his siblings would plow what we call the “Big Field” with horses. It would take them just shy of a month to plow the 100 -plus acres. He was a kid circa 1890 - 1910. This particular field has been a challenge to regenerate and has taught me some great lessons in soil health. Through careful observation and reckless experimentation I have learned a few things along the way.
The five principles of soil health were developed by nature, but the first authors to refer to these principles were Jon Sitka, Jay Fuhrer and Ray Archuleta. I was first introduced to the five principles by Gabe Brown, farmer and author from North Dakota. These principles have been adopted by the USDA and some of the world’s leading soil scientists. The five principles are: 1) limit disturbance, 2) armor the soil, 3) increase plant diversity, 4) keep living roots in the ground all year and 5) integrating livestock. Let’s take a closer look at each one of these principles.
The first principle is to limit disturbance. Physical disturbance of the soil through tillage or overgrazing harms the soil microbial life. Proper grazing management of your pastures will keep the soil covered. Reduced tillage or no-till in cropping systems will limit or eliminate disturbance. Overgrazing has negative effects on the first four principles. Overgrazing is a whole topic unto itself, but the goal is to leave at least 50% or more of the leaf area. The only way to achieve this is through planned grazing with high stock density and optimal rest periods. In addition to leaf area, the height of pasture has a significant effect on soil building, moisture retention, nutrient cycling and water quality.
The relationship between leaf area removed and impact on roots (Cited: Crider, F.J. (1955). Root growth stoppage resulting from defoliation of grass. U.S. Department of Agriculture Technical Bulletin 1102, 23 p. http://babel.hathitrust.org/cgi/pt?id=uiug.30112019332508;view=1up;seq=1):
Up to 40% leaf area removed = no effect on root growth
50% leaf area removed = 2-4% root growth inhibition
60% leaf area removed = 50% root growth inhibition
70% leaf area removed = 78% root growth inhibition
80% leaf area removed = 100% root growth inhibition
90% leaf area removed = 100% root growth inhibition
Bare ground is the greatest enemy to biological activity in the soil, which brings us to the second principle: armor the soil. Bare ground is a direct result of poor management. I will be the first to admit that we still have way too much bare ground on this ranch. Getting the soil covered and keeping it that way has been the greatest challenge at Parker Creek Ranch. This “armor” protects the soil from water and wind erosion. It also provides food and habitat for biological activity below the soils surface. It keeps the soil moist by preventing evaporation. This principle is probably the most critical step in building soil health. In our hot climate where summertime temperatures often exceed 100 degree Fahrenheit for sixty days or more it is critically important to armor the soil. Armoring the soil can be achieved in a myriad of ways that sometimes require a bit of creativity. We have used bale grazing, spread poultry bedding and manure, high stock density grazing to create a layer of litter, pasture cropping and more to create a layer of armor. An interesting observation that I have seen in our hot, humid climate is that litter only lasts a few months. Thus, it’s essential to keep the cycle going. As your soil health increases and biological activity increases it will consume this layer much faster than before. Earthworms and termites also consume copious amounts of litter. I have seen a one inch layer of litter in our pastures reduced to nothing in less than two months by termites alone. I’m not saying this is a bad thing because the termites play an essential role in building soil health by taking this carbon rich material on the surface of the soil and “storing” it below the surface. Have you ever lifted up a layer of litter on the soil surface a week after it’s rained? The surrounding area appears dry, but below the litter there is still moisture on the surface and it’s teeming with life. Consider this when it comes to the effect of temperature on the soil (Source -Gabe Brown, Dirt to Soil):
At 70 °F, 100 % of soil moisture is available for plant growth.
At 100 °F, only 15% is available for growth, the remaining 85% is lost due to evaporation and transpiration.
At 130 °F, 100 % of the moisture is lost to evaporation and transpiration.
At 140 °F, soil bacteria die.
Increasing diversity above the ground leads to an increase in diversity below the ground. This pertains not only to plants, but animals as well. Where in nature do we find a lack of diversity such as our conventional mono-culture cropping systems. Regardless of what ecosystem is present nature always displays a great amount of diversity. For example, the plants in a savanna ecosystem have different attributes to offer. Some are short forbs and grasses with shallow roots, some are large bunch grasses with deep roots that can reach twenty feet or more, some woody species have deep tap roots that break the hard pan. Each species present plays a significant role in maintaining soil health. It is equally important to have a diverse mix of livestock present. Imagine your livestock mimicking a native prairie ecosystem. The best example in North America is the bison, mixed with antelope and birds following them around scavenging through their dung. On farms we can mimic this by having cattle, mixed with sheep or goats, followed by chickens. This diversity of plant and animal life enhances ecosystem functions.
A practice that we have found to be very useful is pasture cropping during the Winter, typically dormant months. There are a few native cool season species on our ranch, but there isn’t much diversity and their grazing qualities aren’t ideal. This practice keeps living roots in the soil year-round. These plants that are actively growing during a time when the land typically lies dormant are feeding live above and below the ground. This principle is particularly important for crop farmers to consider. Soils are at their most productive point when soil microbes have access to living plant material. Living roots provide a food source for beneficial bacteria and fungi. This promotes the symbiotic relationship between plant roots, fungi, bacteria and protozoa.
The last principle is integrating livestock. We already mentioned how livestock are important in regards to diversity. Nature simply doesn’t function without animals. As a rancher our primary concern is the production of forage, in particular grasses. Grasses evolved with grazing pressure over millennia. Soil and plant health is undoubtedly improved by grazing. Good grazing management and practices recycles nutrients through improved manure distribution, reduction of plant selectivity, creating a “mulch” layer on the soils surface and increases plant diversity. Grazing can also be one of the most detrimental tools on our rangelands if not properly managed. Remember the more we can increase our stock density and provide adequate, long rest-periods the better our ecosystems will respond. Through sound management of livestock we are also improving habitat for life above and below the soil.
Our primary goal as a rancher is to make a profit. The only way we can sustain long-term profitability is by improving soil health. As our soil health improves, more grass is grown. As more grass and other plants grow, more organic matter is available to feed the microbial life below the surface. All of these functions capture more water and nutrients, growing more vigorous plants that once again capture solar energy to power the process. This process on your farm or ranch is completely dependent on the management of your livestock. Soil health and the health of our landscapes are interdependent. Following these five principles will result in restoring ecosystem functionality and profit to your business.
- Travis Krause, CEO & Founder of Grazing Lands
