Discussion in 'Pesticide & Herbicide Application' started by Ric, Apr 20, 2003.

  1. Ric

    Ric LawnSite Fanatic
    Messages: 11,969


    Rhizobia are Gram Negative Bacilli that live in the soil. They can not fix atmospheric nitrogen until they infect and invaded the roots of a legume.

    The legume and the bacilli live together in benefit to each other and this is called Mutualism.
  2. George777

    George777 LawnSite Senior Member
    from Alabama
    Messages: 305

    Correct if I'm wrong. I thought when plants die, their tissue is decomposed to release the organic form of nitrogen into inorganic ions by the process of mineralization. Microbes decompose dead tissue to release nitrates, and some are capable of fixating atmospheric nitrogen by a process of nitrogen fixation.

    This process, part of a symbiotic relationship between bacteria (Rhizobia) and the legume roots, involves two chem reactions, ammonification and nitrification.
  3. Ric

    Ric LawnSite Fanatic
    Messages: 11,969


    ammonification to nitrification is oxidation

    nitrification to ammonification is reduction

    Ammonification The process of converting organic N to mineral Ammonium requires enzymes to catalyze the reaction. This is called Mineralization. However mineralization occurs after the plant is dead and is composted.

    Nitrogen Fixing plants are alive and fix N with the help of Bacilli of the Rhizobia genius. This is done by the formation of nodules on the root. These roots will feed the plant the N they fix from the N that is taken by the plant from the air. Roots will die off and the plant will still live. These dead roots are Mineralized.

    All organic matter that has N will be Mineralized to form Ammonia (NH4) this requires N and microbes.

    Nitrogen fixing plants are those that take N from the atmosphere. and fix it in the soil. this requires Microbe from the genius of Rhizobia

    Maybe someone else can explain it better than I.

  4. I can see if i'm going to be any help, I will have to dig out my soil and fertilizer text from college. (1973 or 1974) Didn't grasp this subject as well as I should have ( C), and then it's been 30 years. So help re educate tim!!

    Keep up the good work!!!!!!
  5. Enviro Green

    Enviro Green LawnSite Senior Member
    Messages: 324

    I can see that to keep up with Ric I will have to be faster on the keyboard.

    Rhizobia which fix atmospheric nitrogen to a plant usable form are plant specific. Meaning that Rhizobia from alfalfa will not form the symbiotic relationship with clover plants, nor with soybeans, etc.

    During this process of N fixing by Rhizobia additional N is deposited into the soil profile that can be utilized in the coming months and even year.

    Nitrogen is the most yield limiting nutrient on Earth. Phosphorous is the most limited nutrient on Earth.
  6. Ric: i`m not saying that i`m smarter than you, because i`m just a rookie and u`ve proably been doing this longer than i`ve been alive. but i did`t know how far u were getting into it.
    Now isn`t Nitrobacter an organisum that uses nitrate for food?(some thing like this) and reduces it to ammonia which is nitrogen fixation. i`m trying to catch up i`d like to learn from this, i`m gonna get my pesticide applicators license this summer. and this thread might help me under stand a bit more.
  7. hustlers

    hustlers LawnSite Senior Member
    from MN
    Messages: 257

    to make things easier why cant
    they come up with a species similar to grass that is
    a legume or a N-fixing plant to solve alot of Nitrogen problems

    When I worked on a coffee farm we planted
    "Arachis Pintoi" or ground peanut that fixed Nitrogen
    for the coffee roots to use and it also
    made a very attractive and dark green dense ground cover/

    We used weed control mainly for establishment but after a
    year if was self-sustaining as long as it had water and
    an occasional weeding. It need mowing once a year.

    I believe the future to agronomy is to use all natural
    plants to coexist self-sustaining in the environment.

    Less input-less labor-less environmental damage==high quality goods and services.

    As a ag. missionary in Mexico we call these methods of increasing quality and decreasing work. ""APPROPRIATE TECHNOLOGY""

    sorry to get off the subject
  8. Enviro Green

    Enviro Green LawnSite Senior Member
    Messages: 324


    Nice thought with the agronomy utilizing natural plants, but you need to bear in mind your experience is with perennial plants, coffee, and an annual ground nut, however, the majority of our grain crops 90+% are annuals, and our yields in the US are the highest in the WORLD for the most part. Typically legumes are not able to produce enough N in the same season for a companion crop, the N your coffee plants got was from the previous year.

    Not to say that an N fixing grass such as corn, which is a grass, wouldn't't be a great thing. There is research going on that is examining N fixing bacteria in the soil that would provide N to corn, cotton, etc., but it is a long way from practical.

  9. Enviro Green

    Enviro Green LawnSite Senior Member
    Messages: 324


    What about factors which impact mineralization and nitrification? How does the environment affect these processes and should that be something lawn care providers should be aware of from season to season?

  10. Russ

    Russ LawnSite Senior Member
    Messages: 540

    Ideal conditions for mineralization include:
    soils with oxygen content above 5%
    moisture content near the soils water holding capacity
    temps of 90 to 100 F
    soil PH near 7

    Ideal conditions for rapid nitrification include:
    warn temps 75-85 F
    well aerated soils
    PH between 6 & 8
    soil with good water & nutrient levers

    Now the question was "how does the environment impact mineralization & nitrification" Reckon we might have to say that the environment is the limiting factor for nitrification and mineralization.

    Yep, lawn care providers should take note of environmental conditions season to season.

    You guys are way too sharp for me, but I enjoy this thread.

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