|A brittle environment in the dry season, complete with|
Sunday, January 8, 2017
Holistic Management Concepts - Brittleness Factor
As I began to delve deeper into Holistic Management, there were several concepts I thought were just brilliant. The first one is the Brittleness Scale. It is quite simple, really, it is just a scale from one to ten that describes the inconsistency of moisture throughout the year. A rainforest, where it rains almost every day, would be a one. A deep desert, on the other hand, where it only rains a few weeks out of the year, would be a 10.
On the surface, this seems pretty simple of a concept, and not really worthy of a whole blog post. However, like many simple concepts, just a little bit of digging into the impacts reveals just how important of a concept it is.
Do me a favor. Go look up Google Earth. Keep it at a global level. Scroll around a little and look at the little blue-green-tan orb we live on. I’ll wait. Did you notice how the land masses of the world are predominantly either green or tan in color? That is your brittleness scale right there. For the most part, the green areas are non-brittle, and the tan ones are brittle. Obviously, it is a scale, but it’s a good general rule. Now think about the population centers of the world. Where do all the people live? Southeast Asia. Europe. Eastern United States. The west coast of Australia. Japan. The list goes on. These areas are predominantly green. The only significant exception to this rule is the Middle East, but those civilizations started in the river valleys, primarily of the Nile and the Tigris and Euphrates rivers, prone to seasonal flooding and deposits of rich soils.
The non-brittle environments are easy places to be successful in agriculture. There is always plenty of water for humans and our crops. The soil is always trying to build itself up. Heck, just leave it fallow for a couple of years, and the weeds move in and build the soil back for us. Because of this, these areas are where we had the stability and prosperity to settle down and develop civilization, including institutions of higher learning. They are where science was developed. They are where that science was used to study the best way to maintain crops and soil fertility.
So what’s the big deal? Why is this such an important idea? Well, the first thing is a subtle point, but like most subtle points, makes all the difference in the world. Brittleness doesn’t indicate the amount of water an environment receives, but rather the consistency of available moisture, including humidity. See, an environment functions by breaking down organic matter from one organism to another until it is returned to its constituent parts, returned to the soil, then upcycled into plants to begin the process again. Every level of this process requires available moisture to break down organic material.
When I first moved to Prescott, AZ in 2002, there was a rather large tree, probably 30’ tall, that was right next to a highway I traveled regularly. The tree had already been dead long enough that it had lost all of its bark and all of its small branches. But the large branches and the trunk remained. It wasn’t for another 4 or 5 years that it really started losing the big branches in earnest. It was probably around 2010 that the tree finally lost its last branch and a little after that that it fell over. In a nonbrittle environment, this process wouldn’t have taken more than a few years rather than the probably 15 or more it took in this brittle environment. And Prescott is probably a 7 on the brittleness scale.
When an environment is extremely dry and has little to no rain for long periods (Prescott can go 5 to 6 months at a time with no rain at all), the biological processes that drive can only operate for, at most, a couple of months out of the year. So how does the ecosystem function without the extra moisture?
It turns out that nature is extremely adaptable, and perennial bunching grasses end up being key to brittle ecosystems. They do several things for the ecosystem. At the beginning of the rainy season, the grasses expend stored energy from their roots, sacrificing the roots and pushing their blades skyward as fast as possible. Once they are full grown, they make use of the fertility in the soil, the available rain, and plentiful sunshine to replenish the stored energy in their roots. Once the roots are ready, they produce seed heads and go dormant, usually about the time their rainy season is over. There they will sit until the next rainy season.
But they have some pretty strict requirements. They can be grazed during the rainy season, but if they are overgrazed during this time, they won’t have the energy to store in their roots and take full advantage of next year’s rainy season. They also need to be grazed completely before next year’s rainy season. If the dead foliage isn’t removed, the new foliage will be choked out just as it is trying to grow. Lastly, it needs a heavy dose of fertilizer. I’ll get into the animal impact needed to make this happen in my next post.
One of the most important impacts of this environment is how it manages its own water. The annual cycle of the grasses sacrificing their roots and growing new ones has the effect of “pumping” carbon into the soil. That carbon feeds the soil microbes and increases fertility. More importantly, for every 1% increase in soil carbon, every acre has the ability to store an ADDITIONAL 60,000 gallons of water. So if there is only one percent carbon in a field, it can only store 60,000 gallons of water when the rains come. But if you can get that number up to 5%, the same acre of land can store 300,000 gallons of water. And the prairie grasses can send their roots 6 feet or more into the soil, helping that water penetrate deep into the soil, where it will be stored.
Most brittle environments are prone to heavy rains when the rains do come. Without this natural cycle and a healthy grassland ecosystem, the soil carbon is lost and the water runs off, causing erosion as well as lost moisture. When the grasslands are restored to a more natural system, so much water is stored that ephemeral streams often start flowing again, providing a permanent supply of water to the animals that roam in these environments.
Grassland ecosystems can be some of the most productive on the planet, but only if the natural processes that make them so are fully understood and upheld. If the right level of animal impact is fostered, these ecosystems can begin the process of self-repair in just a couple of years and provide a great source of solar dollars (I’ll talk about that one in two posts).