I was intrigued by our trip on Saturday, to see an example of Permaculture in action, I understand the concept of mutualistic systems and of taking advantage of all areas to increase production in food. My biggest question though, as a student who is interested in repairing damaged ecosystems, is how does this impact the environment if we are altering soil contidions, altering topography and landscapes and introducing plants that would normally not be seen in this area? How do these alterations and introductions change the biota? Is it possible to utilize this theory with native species? I am interested in this question for my final project for the class. On the other hand, I was interested in the orchard area, as it seemed to be the most fully developed example of Polyculture design.
In the Homestead area and built environment we find disturb soil and areas that have been previously altered. In the Permaculture zone system, one through 5, you will see that zone 5 is the natural space. Much of the area on Southwoods that we see but did not walk in his undisturbed wetland or woodland. The areas that we traveled were obviously altered from their natural state sometime ago. This is a tough balance for our Homestead that is trying to be sustainable in its horticultural products for the occupants while respecting the natural capital and ecosystem that surrounds it.
In every project where I have done earthworks, the soils have been turned over and depleted either by construction or agriculture. In building a slight change in topography whereas we can catch water on the land we are beginning and accelerating its repair. In Permaculture much of the time we are trying to accelerate succession so that we can benefit from it more quickly or at least during our lifetime. By building the swales on a hill we are adding structure to catch and store the natural energies and resources on the land that otherwise would be lost. Centuries ago the soil was deep and most likely heavily wooded or in the Prairie. These areas caught and held the sunlight and the water that fell on them and were only subject to disturbances from wind and fire, with the occasional micro disturbance of pocket gophers, badgers, and Buffalo that turned the soil. There is no reason to disrupt the natural areas that have been yet untouched. By accelerating the succession of the other disturbed areas on the property to a highly diverse palette of species we bring an opportunity for a diverse palette of insects, birds, and animals. Left on its own like you see in the back of property, which is in some areas in natural succession, you see reed canary grass and popular. Perhaps some goldenrod and a few other species. Augmenting this area by building a “naturalized” forest edge we can plant species that will maintain the high diversity. This diversity also supports the soil biota and reduces the opportunity for an basis. The 7 layer forest design is part of this process.
As far as "altering soil contidions"
Some people term this as "sacrificed space". The areas that we develop for human purposes; the annual garden, the Orchard, even beneficial insect habitat.
We alter the soil conditions immensely. Relative to better or worse depends upon the gardener or farmer. We have a bias towards rich loamy soil that grows healthy crops and drains well. Taking an area of the yard that is heavy clay, bringing in organic material and developing that space into rich dark soil with good structure will change that space forever. That patch of soil most likely will carry a completely different set of plants if it is ever abandon. Like a battery that patch of soil is now hugely loaded with organisms, minerals, and nutrients for whatever lucky plant establishes itself there. That is what we are trying to do in a small space to grow our food so that we do not have to interfere with a larger natural space or forage.
Directly altering the soil conditions is extremely expensive and time-consuming, not to mention a waste of time if done poorly. As you can imagine, shipping and compost, wood chips, and spreading mulch should be kept to a minimum of our intensive production areas. On the other hand, developing a poly-culture of plants that are tailored to the soil as it is, within the climate that they can thrive, will over time also change the soil, but only if the plants and the soil organisms are mutualistic in nature and well-paired.
if by altering the topography you are referring to berms and swales, it is increasing the available soil moisture to the surrounding plants in the niche. Is allowing the plants that we place on the berm to have adequate water during dry periods. It is expensive and time-consuming, and something you would probably not do in a wilderness area that already has its water holding capacity built in by the existing plant structures. In Homestead and farm design we alter the topography of farm fields to reduce erosion and catch water for the new system of plants that will be implemented. Many of these fields have had their topography altered over generations. If you were going to try and rebuild the Prairie on much of these lands you would not need to alter the topography in most cases. If you want to put the land into agroforestry, alley cropping, or larger plants after it has been repeatedly disturbed, you would need to do some major soil repair which would include earthworks. When settlers first moved to the far West middle West and decoders there was 6 feet of topsoil under the Prairie. Over the last 200 years that topsoil has been depleted to about 12 inches. Using a subsoil or or key lime plow to break up the hard can under an agricultural field, we are allowing nutrients and plant roots to now begin to re-create that deep topsoil. Initially this may look hugely destructive to have a large tractor or Caterpillar bulldozer ripping through the soil, but what it is doing is putting back the fissures in the cracks the air and moisture that had been there previously before its agricultural compaction. The first step to build the soil back is to give it water and organic material by way of deep rooted plants.
and landscapes and introducing plants that would normally"
Naturalized plants, native plants, invasive plants, are subject to great discussion and bias. What is normal? Humans bring with them the animals and species of plants that they want to propagate. The landscape that we see now is not normal in a geologic sense. The animals that occupy the landscape are not normal relative to 300 or 400 years ago. At last count I heard the deer number 20 per square mile in Minnesota. Because a huge amount of damage to the ecology, but are seen as normal on the landscape although they are 4 times the number they were prior to settlement. It is normal to have wolves in Minnesota taking down deer populations. It is not normal to have coyotes or possums here. in the last 150 years this landscape has been changed with only small pockets of old-growth ecology. There is a huge influence of cultural bias which shapes our perception of how we think things should be. I think if we can sustain ourselves on the land while supporting the existing ecology and improve soil health, we have taken a great step to improve and repair our environment. This needs to be done without mowers, tractors, and bobcats in the long run. What we are searching for in this course is the ecological solution using the plant systems that already exist to create spaces for over yielding harvests so that we can leave those other spaces sacred.