One option to establish a new garden while minimizing the disturbance to existing soil life would be to apply mulch directly on top of the existing vegetation. This would work best for areas covered by grass and other types of non-woody plants. If you put down
cardboard (remove the tape) and then place organic mulch (woodchips, untreated
straw, leafs, leaf-mold, etc.) on top the existing vegetation will break down and feed the soil life. You could do cardboard, a layer of compost/soil, and then the mulch too which would give you a medium to plant into. If you don't want to use cardboard make sure to have a thick layer of mulch 8 inches or more to make sure the existing vegetation does not push through.
An advantage of this system would be that you would build soil and the decaying vegetation and mulch would feed much of the soil life. But you are still changing the system so you will see a change in the soil life community. Some critters will like the new system better than others.
A disadvantage would be the time it would take for the system to get established. You would need to wait for the existing vegetation to breakdown before planting. Adding a layer of compost/soil to the mix would let you plant sooner since you would have something to plant into.
I would recommend doing the prep work in the summer (placing the cardboard and mulch down) since a lot of the vegetation would be dormant due to the heat depending on your climate. Then let it all sit over fall and winter and then plant in the spring (you could potentially plant a cover crop late summer / early fall). The first year I would plant things like carrots, potatoes, squash, peas and beans. They should do fine even if the old vegetation is not fully broken down. By the following year you should be ready to plant anything you wanted.
If you do this you will see a change in the soil life but not a die off. Anything we do will change the soil life - I read a research paper as part of my masters program that talked about taking a soil sample and just by analyzing the soil life they could tell you the age, diversity and structure of the plants growing at the site without anything other than the soil sample. So if you take any area and add new plants to it, or start walking on it, etc. you will change the soil life. I think the key is not to avoid change but to avoid a loss of diversity and total population of soil life.
If your site has woody plants than just placing mulch down might not be enough to transition the site. But you can cut down some of the woody plants where you are trying to start a garden and then use the resulting woody debris for mulch or to build a hugelkultur bed (buried wood beds that once established need very little to no supplemental water. Mimics a nurse log except that by burying the wood decomposition is sped up). This would again change the soil life but would create rich habitat for fungal systems and other soil life and would lower water needs.
Once your garden beds are established I would recommend using fallen logs and large branches as borders along the beds. You could also use rocks and ideally mix it up a bit. The reason is that the wood/rocks will create edge around your beds that will support and
shelter soil life and other critters. In my area we have garter snakes that eat slugs - so by placing rocks I can create habitat for them so they hangout and eat the slugs where I need them. When you work your garden you will naturally avoid the rocks and logs which creates nice little sheltered areas. I also place logs around the edges of all my trails/paths for this purpose - it also looks nice.
I'm also planting
native plants around and in every one of my beds - sometimes this might just be a few lupines or something small but since plants influence the makeup of the soil life I like to always have some native plants to better promote native soil life. This also creates small no disturbance areas in each of my beds and can go well with rock piles and woody debris.
I'm also planning for my new garden to build a mostly native and perennial bed in my garden for every 2 or 3 "normal" garden beds that focus on annuals. These "wild" beds will provide habitat for beneficial insects and other critters. Plus they will be good for soil life. Then along the borders of my garden I will be establishing hedgerows to help with water retention and also provide habitat for critters both above ground and below.
Finally, the other thing I would recommend is to not have isolated islands of fertility. What I mean is that often I see people create a garden, mulch it,
fence it, and then do nothing with the land around it. They might then have a few fruit trees in another area that are also isolated in their own little islands of fertility. If you can instead connect each area that you are gardening, growing perennials, etc. you can provide pathways for fungal systems, other soil life, and above ground critters. Fungal systems can extend for thousands of feet and help transport nutrients and water from one area to the next. I think providing corridors for this sort of thing is very beneficial.
julian Gerona wrote:
Joel Bercardin wrote:Back when I did that, foresters were teaching that in a conifer forest, most of the nutrients are not in the soil but in the trees themselves — until the tree dies, decays, and returns the nutrients to the soil’s biological processes.
I have some problem believing in this teaching. If its true the mountain tops and ridges and inclined surfaces should be barren or nutrient deficient from thousand of years of nutrients wash off. But as we can observe they are as lush as horizontal surfaces. In many cases/fields I have discovered that official teachings are false. Most probably business interest and dubious agendas. You see studies and researchers are funded by big business interest for their own good.
To add to this part of the conversation... My understanding as a restoration ecologist is that overtime a forest (at least here in the Pacific Northwest) does retain much of the nutrients in the trees. But this was most evident back when our forests were all old growth forests. The natural succession back then was for a huge old growth tree to fall, open up an area to light, release nutrients, and feed the next generation. This next generation would start with trees like red alders, shrubs such as ceanothus, and other early succession plants. These light loving plants would rebuild the soil and make room for more shade tolerant plants such as red cedar, grand fir and western hemlock. Overtime, these shade tolerant plants would close the
canopy and return the forest to its prior state and the cycle would repeat with the next large tree fall.
If you look at the size of the old growth trees - just one of those falling would open up a huge area. Plus the research I'm familiar with indicate that these old growth trees would take several hundred years to decompose once they had fallen. The same research has also shown that these fallen trees contain more living biomass than the same tree would have contained when it was living.
Of course I'm talking about the wet forests here in Western Washington. In the drier areas you would have fires come through and clear areas of trees but also leave a lot standing. This would create open areas, lots of down woody debris, and a similar process would happen as with one falling old growth tree except on a larger scale. In fact ceanothus seeds germinate much better after a fire.
My understanding is that the forests we have today are actively being starved of nutrients because this cycle is being blocked. Early succession plants are often killed off to favor the timber trees and no woody debris is left on the site to return nutrients. It is the same process that happens when we remove a crop without returning anything on farmland. Some research indicate that here in the Pacific Northwest by mid-century much of our current forest lands may not be capable of growing trees for timber because of the loss of nutrients.
A healthy forest in my area has tons of down woody debris. So even on a slope the nutrients don't wash away because every down log captures nutrients and also there is so much soil life and organic material in a healthy forest floor that the water is absorbed and does not cause erosion. But these forests also did not historically have earthworms and since they were introduced the breakdown of the forest floor has sped up which has caused some issues though it seems like the logging practices are causing far more issues in regard to depleting the forest floor.
That being said there are plenty of areas in the mountains around here that are more "barren". These areas such as avalanche shoots don't grow large trees but other plants such as Sitka alder do grow in these areas and protect the soil and also help rebuild it after a disturbance. Much or our mountain tops and ridges are naturally more bare or I should say only support low growing plants - these areas tend to be harsh and exposed to the elements. You get high enough around here and you get above the tree line and then you find alpine meadows but with climate change these meadows are starting to see trees push in and replace them.
So my thought is that the nutrient cycle is part of a normal forest with old growth trees holding a large portion of the nutrients and then releasing those nutrients when they die. This does not favor big business - since by logging and removing the trees they are also removing the nutrients from the land. If anything understanding this nutrient cycle is an argument for keeping dead trees on the land and not removing them for processing. If the nutrients were not being stored in the trees then you could haul them off through logging as much as you wanted to with no impact to the soil. Its the same process that happens with industrial farming.