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Nutrient cycling in soil

Discussion in 'Organic Lawn Care' started by ICT Bill, Dec 28, 2007.

  1. ICT Bill

    ICT Bill LawnSite Platinum Member
    Messages: 4,115

    I had someone ask me about this and I gave my long winded answer about photosynthesis, beneficial microorganisms, blah, blah, blah, blah

    After several minutes I noticed dead air on the other end, I said are you following me and the answer was NO! "I am not a soil biologist and don't understand what you are really saying can you bring it down to a level I can understand and I can explain it to my customers"
    So I wrote this, (I'm no soil biologist either) lets see if we can beat it up and try to fine tune it so it is really simple. Since this is the organic lawn care section it is tailored to folks using organic methods.

    Nutrient cycling
    Grass plants need sun, water and nutrients in the soil to thrive. The sun’s rays provide the means for the plant to turn the sun’s energy into sugars, proteins and carbohydrate (photosynthesis) and store this food in the root. Up to 40% of the food stored in the root is pushed out through openings that feed the good guys in the soil that live there, beneficial microorganisms.

    Organic matter has a complete line of macro/micro nutrients but they are in forms that are not available to the plant for immediate uptake. These forms of nutrients are non-leechable and do not wash away with rain but are held in the soil until needed. The good guys in the soil love to eat organic matter and through a process called nutrient cycling make these nutrients available to the plant. This process of applying organic matter and supporting the good guys in the soil increases soil fertility which, in turn, increases soil porosity, disease resistance, drought resistance and makes healthy green turf.

    We support and increase the good guys in the soil by applying compost teas. These compost teas do not contain any animal waste (this is not always true), but are a rich mix of organic nutrients with dense populations of the good guys that live in the soil. The beneficial microorganisms in compost teas populate the root, shoot and soil of the turf and begin a process termed “the soil food web”. The soil food web describes in scientific terms the symbiotic relationship between plants and beneficial microorganisms in the soil.

    Clay soils have 1000’s of years of nutrients in them, it just that the nutrients are not in plant available forms. By initiating the process of adding organic matter and supporting the good guys in the rhizosphere, the root tips begin to reach deep into the soil increasing the soil tilth and root mass and tapping sources of nutrients that have until now been unavailable to the plant.

    Synthetic or non organic nutrients
    The application of synthetic fertilizers to the soil discourages root growth and drought resistance. Think of it this way, if someone was to feed you all of your nutrients needs, eggs, steaks, french fries, etc. in the same place every day why would you ever go somewhere else? Well, OK you have a car but plant roots don’t.
    As we apply these, immediately plant available, nutrients to the soil, they melt and drop into the top one, maybe two inches of soil. If you ever dig in your yard you will notice that the roots really do not go down that far. Why would they? All of the nutrients are in the top 2 inches of soil. During times of low moisture and high heat, which is known around here as SUMMER, the roots do not penetrate far enough into the soil to be able to reach cooler wetter soils and suffer the consequences. If we begin a program that encourages increased root mass and penetration into the soil we dramatically increase drought resistance and health in turf.
  2. tadhussey

    tadhussey LawnSite Senior Member
    Messages: 294

    Easy to understand. My only additions might be to describe a bit more about how the whole process works biologically. (The bacteria take in the organic matter and convert it in their bodies. They are then eaten by larger protozoa such as flagellates, amobae, and cilliates, and the waste products that come from this are now plant available).

    You might also want to mention what some of the nutrients are and how they relate to chemical fertilizers (the whole NPK emphasis of chemical fertilizers). I also noticed you added the word rhizosphere towards the end of the article, while you referred to that area in the beginning just as the root zone. You may want to explain that if someone has no knowledge of these terms.

    One of my favorite stories was told by Jeff Lowenfels. He uses it to open his lectures on the soil food web. He talks about how miracle grow was first invented and exactly how it works. He then goes on to talk about how it needs to be highly concentrated because very little of it actually comes in contact with the roots and the rest just washes through the soil. This also establishes a dependency on fertilizer, as most of the biology that promoted nutrient cycling in the soil gets killed through osmotic shock (the high salts in the miracle grow). I shortened his intro, but you get the idea. I thought it was an ingenius way to get people thinking about the biology in the soil.

    Finally, you may want to emphasize the benefits of letting nature handle the nutrient cycling. Many consumers just want to know what it's going to do. Is it going to help them grow bigger plants? Is it safe? What makes it better than using chemicals?

    I've found that when I start to explain the soil food web, I get a similar response. Many people just don't care. They just want to know what they'll have to do, if it will work, and what the benefits are going to be. If in their mind the benefits outweigh the time and the cost, then they go for it.
  3. rcreech

    rcreech Sponsor
    Male, from OHIO
    Messages: 6,153

    True Nutrient Cycling, like looking at a lawn for example in not returing your grass clippings! That is where the plant uses N,P and K and then is returned and the plant keeps using the same nutrients. If you are applying and outside source such as organic material or fert that is technically not Nutrient Cycling.

    I don't think you are correct in saying that a fertility program will dictate how deep the roots go in a soil.

    Is adequate fertilizer needed for good plant/root health? YES

    The root system/root mass is bases on more physical things such as core aeration, mowing height etc.

    Using a organic fert is no different then using a chemical fert to the plant. The plant only knows K+, PO3- and NH4+/NO3-.

    The plant could care less if "organic" or chemical!

    You can use that for a sales pitch...but it is pure bologna!
  4. rcreech

    rcreech Sponsor
    Male, from OHIO
    Messages: 6,153


    True Nutrient Cycling, like looking at a lawn for example is returning your grass clippings!

    I said not returning your grass clippings originally as that was a typo!
  5. Gerry Miller

    Gerry Miller LawnSite Senior Member
    Messages: 504

    Actually, what drives your lawn's roots to go deep in the soil is determined how you water your plants. By adding only one inch per week, given all at one time, will allow the soil to dry out and the roots will go deeper in the soil looking for moisture. If you water a little every day, the grass roots will stay near the surface and not go very deep into the soil at all. This process also keeps weed seeds from germinating. You grass roots go deeper into the soil than the roots of weeds, for most part.

    In addition, proper mowing height for the grass you are growing is also a factor. Like with Kentucky Blue Grass, the taller you let your grass grow will also assist grass roots to go deeper in the soil as well.

    As far as the plants not knowing the difference between organic and synthetic is debatable. The soil biology that feeds the plants certainly knows the difference. The don't even work the same way.

    "Chemical fertilizing, however, takes a different approach. It is based on determining the major nutrients required for each type of plant to grow and then produce a fertilizer that supplies those nutrients. What sounds like a simple solution actually creates a dynamic of problems.

    Although the plants initially look fine after chemical fertilizing, what is going on within the soil is not. The salt content of chemical fertilizers is toxic to microbial life. Regular chemical use continues to deplete the soil of vital microorganisms and begins a cycle of problems. Soil compaction, less vigorous growth and fewer flowers, susceptibility to insects and diseases are some of the more obvious symptoms. Some are more hidden and go unnoticed by the untrained eye.

    Chemical use begins a vicious cycle of dependency. The chemicals strip the soil of life and leave the plants dependent on their fertilizer "fix" for any nutrients. When the chemical fertilizers wear off or leach out of the soil, they leave nothing behind to create or supply nutrients to the plants. The plants then start to show signs of stress or die and more chemical fertilizers are added to give the plants another chemical "fix".

    Chemical pesticides are often introduced to combat diseases or pests taking advantage of the plant's weakness. These sprays strip the plant's natural microbial protective coating leaving it susceptible to more disease. These problems create extreme stress on the plants that the fertilizers & pesticides cannot cure. In the end the result is poor quality plant materials, high plant mortality, poor soil conditions and poor water quality.

    In order to truly look at the chemical approach it is important that we also look at the incredible evidence of harm created downstream from the use of these products. Toxic compounds not only harm our ground water, streams, oceans, and wildlife, they harm our children, our pets, and our own health. A World Resources Institute study has determined that the fresh water systems around the world are so environmentally degraded that they are losing their ability to support human, animal and plant life. 93% of fresh water is used by agriculture that produces runoff that degrades water quality with silt and chemicals."


    From the former monitor, David Hall:

    "The problem with using even small amounts of chemicals is that they do not provide any food to the microbes. There is no protein, carbohydrate, vitamins, minerals, or enzymes in these purified chemicals.

    Here's a list of things an organic program can do that no chemical can do. The beneficial microbes in the soil do the following.

    1. Decompose plant residues and manure to humus.
    2. Retain nutrients in humus.
    3. Combine nitrogen and carbon to prevent nutrient loss.
    4. Suppress disease.
    5. Produce plant growth regulators.
    6. Develop soil structure, tilth, and water penetration/retention.
    7. Clean up chemical residues.
    8. Shift soil pH to neutral and keep it there.
    9. Search out and retrieve nutrients in distant parts of the soil.
    10. Decompose thatch and keep it from returning.
    11. Control nitrogen supply to the plants according to need.
    12. Pull minerals out of inorganic soil components for plants.
    13. Provide the exact chemical nutrients to the plant that the plant has evolved with rather than man's cheapest chemical approximation.
    14. Provide exactly the required quantity of nutrients that the plant needs.
    15. Provide the nutrients at exactly the right time that the plant needs them.

    No chemical can do any of that. To be fair, no single microbe can do all of that either. In fact, it could be that it takes 10 different species, one working right after the other, to do any one item in the above list - sort of like a microbiological assembly line. But at least it's real easy to get all the right microbes. The biology of the soil is very complicated.

    At the same time, many chemicals inhibit the microbe's natural abilities to do these things. Herbicides, fungicides, and pesticides are all designed to kill various biological life. As a byproduct, they often kill off the beneficial microbes that are doing 1 through 15 above. Any break in the assembly line can interrupt the process, damage the mini ecosystem, and lessen the benefit of the organic methods. This leads to disease."
  6. ICT Bill

    ICT Bill LawnSite Platinum Member
    Messages: 4,115

    RC, I have no idea what the definition of "true nutrient cycling" is and maybe I used the wrong term to start the thread and..... we may have to agree to disagree on different ways to keep lawns healthy and green. but...

    The basic premise of organic lawn care is to eliminate fertilizers in the sense that you are feeding the plant. displacing one fertilizer for another is not the optimum solution.
    The goal is to feed the soil and make it a healthy balanced web of beneficial microrganisms, that in turn makes a very fertile soil to grow grass or anything else you want in.

    This is exactly what I was talking about, we may be able to discuss the subject and get down to very fine details and split hairs about all kinds of things but how does the average homeowner that is thinking about organic lawn care mentally digest it? How do you inform them without having to send them to a local university for a semister.

    The basic premise in organic lawn care is not having to use fertilizers or at least a drastic reduction, am I wrong?

    If I tell someone that runs a car dealership that there are many bacillus strains that are plant growth promoting and many solubilize phosphorous and that you can increase the life and health of mycorrhizae by applying mycorrhizae helper bacteria. And by the way there are 4 different types of nematodes and only one of them is pathogenic. I'll have to give him a good shake to wake him up from his nap.

    RCreech, I have read a lot of your other posts on the board and you obviously speak from years of training and experience, but I have to disagree with you on your sales pitch comment.

    There are a couple of folks that have been doing organic lawn care for more than 20 years that I work around at times, the results of the sites are outstanding and something you would applaud. The results are the same and somtimes better than your program, its just different than your program. None of these companies use fertilizers.
  7. rcreech

    rcreech Sponsor
    Male, from OHIO
    Messages: 6,153

    I would agree that watering frequency can also determine the root depth to a certian extent.

    That would be anohter physical action or physical source. My point was that fertilization doesn't determine root depth.

    Yes if you add tons of OM to the soil you will increase microbial activity...but I think you are going a little far as to discuss salts. When we are only applying 3#/1000 of a product the salt is more minute then a needle in the haystack!

    I don't want to get into the chemical vs organic thing as that is like debating poitics or religion. There is no "right" answer!

    I just wanted to state the case that the plant could care less where it gets it nutrients and that there is a lot more to root mass/depth then fertility!

    Well I am going back to the "chemical and pesticide side" where I fit in better! :laugh:

    Have a good NEW YEAR!:drinkup:
  8. Gerry Miller

    Gerry Miller LawnSite Senior Member
    Messages: 504

    The secret that certainly nobody knew about, or at least we gardeners didn't know about, was that the microbes need to eat protein to become healthy enough to protect themselves, the plants, and other beneficial creatures (including insects). Now we know what to do. Having an organic soil is not nearly enough. You have to feed protein to the microbes in the soil. I use various protein meals for fertilizer during the course of the year, such as corn gluten meal, alfalfa meal, soybean meal, and fish/seaweed liquid fertilizers. Adding organic matter alone is not enough. Protein meals will provide the micro herd with the food they need to excel.
  9. ICT Bill

    ICT Bill LawnSite Platinum Member
    Messages: 4,115

    I agree with you that the debate can get to a fever pitch but that is not what I was trying to get into with this thread but to lay out in some simplistic ways how organic lawn care is approached.

    Thanks, I hope you have a very profitable new year, come back your input allows a different view that is valuble

    It sounds like we could go back to the basics that are on every lawn site, cut at the right height, leave the clipping, adjust your watering for deep watering, etc.

    But how do I say that the ciliates and protozoa numbers in the yard are down and the hyphal diameter of most of the fungi suggests that the soil has been anaerobic for some time.

    or at least how do you put that on a flyer and hang it on their door
  10. Gerry Miller

    Gerry Miller LawnSite Senior Member
    Messages: 504

    Well, I have to disagree with a few of your assumptions.

    You do NOT have to drop tons of OM to increase your soil biology. It can be simply performed by using AACT. In fact, this will supercharge your soil with the biology you plants need. This will, without a doubt, increase your plants root growth. It's been proven. Dr. Ingham has produced such results, showing some grass roots to reach 10 ft. Root Depth is also a function of the soil compaction. Using AACT will provide the soil organisms that will break up compaction and allow roots to go much, much deeper. But like I have already stated, the microbes need to be feed, and protein meals fits the need. So indirectly, microbe food, fertilizer, is needed.

    Any amount of salt kills soil organisms, no matter how small the amount, it does damage. There is no dispute of this fact either.

    And there is a 'right' answer and it's being organic and not using synthetic chemicals as they do more damage than any good. To not recognize the tremendous differences between synthetic and organic fertilizer is just ignoring the facts.

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