Soil structure through succession

Discussion in 'Organic Lawn Care' started by ICT Bill, Mar 27, 2008.

  1. ICT Bill

    ICT Bill LawnSite Platinum Member
    Posts: 4,115

    I have finally remembered to post this chart. I'll get back to it this evening

    Heavily disturbed soils start at the top left and the chart moves around to the right to old growth forests.

    The point I have made in several posts is that the soil on a site is somewhere on this chart, lets say 1:1 for an example. If Newby sprays his Pre-M on this soil where will the succession go, backwards I would assume.

    How far backwards? It depends on the amount of the distrurbance. How do we measure a disturbance?
    Soil Bio-Assay's

    If we are trying to repair the biology because of a disturbance we can do that quickly by spraying compost tea, compost will attain the same goal just in much longer time frames.

    Soil food web succession.gif
     
  2. Kiril

    Kiril LawnSite Fanatic
    Posts: 18,308

    I think a couple of good questions would be:

    How do we define disturbance?

    How do landscapes fit into that succession chart?

    Pick just about any landscape, and in many/most cases you have no less than 4-6 of those succession stages "represented" on the same site.
     
  3. ICT Bill

    ICT Bill LawnSite Platinum Member
    Posts: 4,115

    Kiril, I agree completely

    What this information shows is that there is a relationship between the biology in the soil and the plant that is there. Basically Prarie grasses like a more bacterial and less fungal environment, woody plants like a little more fungal than bacterial, trees like a much more fungal environment.

    If we are trying to have far fewer inputs, we try to get the biology in the soil right, in this way we have in place the nitrogen fixers and phosphorous solubilizers for grasses, trees it seems doesn't need these guys as much as the fungi.

    this chart gives us a good indication of what we should be feeding the soil in order to support the type of growth we are trying to support. If we are very early in succession and we are trying to support turf we need to feed the soil things with complex sugars in them, bacteria love sugars, as well as fungal type foods like humates or fish. In this instance we are trying to get bacteria and fungi up in the soil. This would be true in new construction sites
     
  4. Kiril

    Kiril LawnSite Fanatic
    Posts: 18,308

    I feel the problem with complex landscapes is how do you pick which succession stage to go for? If you only have turf with nothing else, then your choices are easy.

    Now let's add trees, shrubs, annuals, perennials, etc... into the equation, all of which have the potential for their respective root systems sharing the same volume of soil.

    Do we go for a happy medium, or do we try to "micro"-manage these soils on a plant by plant basis?

    I can see a potential problem with regard to this and organic management practices. The mantra of feed the soil, not the plant has just as much potential of being resource intensive as synthetic alternatives.

    So this leaves me with the question; Are we really solving the problems created by the use of synthetics or have we merely shifted the problems related to landscape management to the soil instead of the plant? Instead of trying to maintain acceptable levels of nutrients, we now are trying to maintain acceptable levels/ratios of microbes.

    Yes, I believe organics is by far the better solution, however I fear we are not really solving the bigger problem with respect to resource usage. It's like putting a fresh coat of paint onto a wall infested with mold. It looks great for a while, until the mold starts to come through your new coat of paint, and you back where you started.

    Have we simply redefined the problem by trying to establish and maintain an "artificial" system that would not be naturally sustainable without intervention on our part?

    These potential problems is the reason why I push for regionally sustainable landscapes.
     
  5. ICT Bill

    ICT Bill LawnSite Platinum Member
    Posts: 4,115

    I have a problem with the premise that it is a problem

    If we look at natural systems, a forest for instance. leaves, branches, etc fall to the forest floor and are "mined" by weathering and the biology that lives there. There are a lot of fungi in the make up of this soil because that is what they like to do mine cellulose, which eventually becomes plant available nutrients. There aren't a lot of bacteria in this environment because there aren't a lot of foods here that bacteria like to eat. As a result the trees unknowingly (some have different opinion on this) select for a fungally dominant soil make up.

    If you look at plains grasses, there is not a lot of cellulose in this environment at least not as much as a forest so we don't see as much fungi. The grasses are constantly reseeding themselves so we see a lot of new root shoots going intro the soil every season. Root shoots are one of the most fertile places in the soil and bacteria love the nutrients that are sloughed (bacteria food) off by the roots. If we look at the make up of this soil we will find much fewer fungi than the forest but much more bacteria than the forest.

    An interesting fact, bacteria move soil slightly acid while fungi move it alkaline. Grasses, in general, like a slightly acid soil, trees like a slighly alkaline soil.

    If we can understand where the soil is in succession and move to a balance that is needed by the plant we can make the conditions favorable for the plant. This is especially true in Ag. The soil food web has been testing soils for a long time and has an extensive database of the bio-makeup for different plant species.

    We can actually manipulate the soil to support one species or another.
     
  6. Kiril

    Kiril LawnSite Fanatic
    Posts: 18,308

    Chicken or the egg scenario here. :)

    Yes, I agree with respect to Ag. Landscapes however are an entirely different animal in that we are not dealing with a monoculture. Let's look at a very common practice in landscapes, your tree in a lawn.

    Which direction do you push your F:B ratio? Based on the numbers in the succession flow chart, I see no way to achieve anything close to an ideal ratio as the differences are just to vast. This now has become a design issue more than a management issue.

    Let us look at irrigation for a moment. Proper landscape design in an irrigated scenario will group plants by hydrozone (i.e. similar watering requirements).

    Now let us take this concept and extend it to biological community management. Perhaps instead of trying to force a system in a particular direction, we should be building the system to support the condition naturally. We can call these biozones. :)

    So we design our landscapes around similar water requirements (hydrozones) and similar biological requirements (biozones).
     
  7. ICT Bill

    ICT Bill LawnSite Platinum Member
    Posts: 4,115

    Kiril,
    In your instance of a tree in the lawn, How many questions have we seen where people ask that question "how do I grow grass under a tree" the answer should be "you can't or shouldn't"

    If we mulch under the tree instead of trying to grow grass we are putting a lot of cellulose (tree bark) down. The mulch is a great food for fungi, have you ever dug down and seen all of the hyphi (small white root looking things) of the fungi in a mulch bed.

    We have now raised the fungal level in the soil that trees prefer

    It isn't rocket science but we have just selected for a better environment for the tree

    On your chicken and egg comment, one of the national parks long time expert Kevin Smith believes that indeed trees think, he has a presentation that is very convincing. He also has a theory that tree exchange information through their roots and large stands of trees actually make decisions together for the long term health of the forest. He has many examples again it is a very convincing arguement. Kevin Smith is about is smart as they get too.
     
  8. Kiril

    Kiril LawnSite Fanatic
    Posts: 18,308

    I'm not trying to say it can't be done, what I am saying is the emphasis should be put on proper landscape design, not trying to extend a long term problem. That problem would be, attempting to force a site/system to sustain plant communities which it could never do naturally.

    I can certainly see the need to tightly control F:B in organic Ag, but in landscapes? This only serves to add complexity to a process that many people already find too complex (even though in many ways it is not). Does that make sense?

    I don't know about your area, but the standard lot size out here is 1/4 acre or less, with scatterings of 1/2 to full acre lots. Even if you don't plant trees in lawn, or mulch around them, there will be vast areas of soil that are not in the "ideal" range because the roots will not stop where we want them to. You see, it is not only a matter of managing the micro herd for a particular succession stage, but at the most basic level, it is a matter of space. Too many plants, too little space.

    Redwood bark is used extensively out here as a mulch, and just about anything that is not lawn, has bark. This isn't done to promote higher F:B, it is done to conserve water, reduce weeds, and for aesthetic purposes. These 3 primary reasons for mulching will always override any perceived or real need to manipulate F:B.

    I oversee landscapes that have both trees in lawns, trees around the border of a lawn, trees mixed with shrubs, shrubs mixed with perennials/annuals, all of the above around lawns, etc... An almost endless variety of plant mixing from nearly all the succession stages. This is just the way it is done, and will continue to be done until we stop following the status quo and create a new one. Isn't this what the organic movement is all about?

    So how do we deal with this very real problem now when we have landscapes that have no well defined bio boundaries, at least not with respect to the succession flow chart?

    Personally, I think the answer (when proper (re)design is not an option) is to promote balanced biological communities in these areas, with no preference to any one succession stage, and let the plants sort the rest out. If you dealing with a sports field, or any large expanse of plants that can be easily fit into one of the succession stages, then by all means, promote what is considered the proper F:B in order to mitigate any past disturbances.

    I'm not entirely sure what the reference to Kevin Smith was for, but thanks for the tip. I look forward to reading some of his findings. :)
     
  9. Organic a go go

    Organic a go go LawnSite Member
    Posts: 211

    Don't about everyone else but I love it when you guys go off on one of these Master's Thesis dialouges. If you'll entertain a question from an incoming freshman.......

    Kiril Im going to assume that you'd say plant diversity creates bio boundaries in nature?? Without that option how else can we select for appropriate F-B ratios without managing inputs? BTW just for the record I agree with much of what you say regarding doing away with turf and your approach to landscapes in general but I often think its odd in my case that someone who thinks it'd be better if the aesthetic moved away from turf is
    running a business dealing with turf. Is this the case of the vegetarian butcher?
     
  10. Smallaxe

    Smallaxe LawnSite Fanatic
    Posts: 10,082

    I believe it is safe to say that all plants grow better in high OM environments. I believe if you build it they will come. I believe tree roots create their desired microenvironment and their F:B friends flourish in their neighborhood, if provided. Same with grasses amongst them. They have their friends that will support their roots zone and combat their enemies.

    In the real world of landscape health I don't really need to know for sure what F:B ratio/species are extant below the surface. Natural selection takes care of that for me. I don't have a problem with giving an area a boost with the teas, but nature easily takes it from there.

    Japanese Maples in the zone 4 midwest is also real. Its life is sustainable in the correct placement. Does it have F:B requirements different than the weigelia next to it or the hydrangeas in front? I bet yes. A good mixture of many different OM sources support all different F:B ratios and the ones that are happy with one plant will flourish with that plant.

    I am not just throwing this out there. I carefully read the posts and to me, the real issue is the health of the plant dictating whether or not we need to manipulate its habitat or not. We do not enjoy the wilderness prairie look with all its nasty insects here in Wisco. We do not base our decisions on philosophies or microscopic counts but by whether the environment is suitable for our comfort.

    To micro-manage soils is to assume that we [as humans] know more than natural selection provides. That arrogant, control freak ideal has brought us the Asian Beetle and many other wonderful treats over the years.
    Could "growth promoting bacteria" injections to the soil be similar to bovine growth hormone in cattle? or human roids?

    I thought the organic movement was to work sensibly with nature. Lanscapes do not provide us food and they do very well without our constant messing with them. Even grass under most trees :)
     

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