Muriate of Potash, not only a waste of money...

Discussion in 'Direct Drilling Crops & Agronomy' started by martian, Nov 5, 2013.

  1. martian

    martian DD Moderator

    N Herts
  2. Barleycorn

    Barleycorn Member

    Interesting article. Probably why you have to use Sulphate of Pottassium rather than MOP when you are organic, although I thought it more to do with the chlorine.
  3. Andy Howard

    Andy Howard Member

    Ashford, Kent
    I have struggled to find any yield response from potassium fert. There are two problems with potassium. When the plant needs it most it struggles to physically get enough in no matter what the soil levels and also it can be limited by moisture availability.
  4. Barleycorn

    Barleycorn Member

    We have potash deficiency symptoms in our Lucerne as we get 3 very good cuts on very light land. We use compost and sulphate of potash, but according to a well respected mutual friend (Plumbo) even our light land should have enough potash if we could release it.
    In this study they seem to belittle soil test results, but we have tests with 1 / 0 for potash, and speckled leaves, so I think that we are deficient.
    Isn't 'corn belt' land the same soil that blew away in the 30s? I thought that it was of poor fertility?
  5. what chlorine?
  6. Rob Holmes

    Rob Holmes Moderator

    Was talking to someone from Glenside at Croptec last week about this,

    He said that Yes, MOP is damaging to soil but only really has an effect when applying over 500kg/ha per application. If you apply 150kg/ha every 2 years then there will be no noticeable difference
    He used the example that alcohol is bad for us, and will kill us if a big enough amount is consumed at once, but the odd pint is ok and shouldn't kill you
  7. C.J

    C.J Member

    South Devon
    Murate of Potash (M.O.P) is Potassium Chloride(KCl)
  8. Renaultman

    Renaultman Member

    The other interesting point id the potassium returned to the soil. Would that affect a model where straw is removed? It does seem that we are probably better off unlocking K rather than adding more. Soil science is probably the next big step in crop productivity IMO
  9. rob1

    rob1 Member

    Only just starting to scratch the surface of what soil science is imk. Pun intended:)
  10. Warnesworth

    Warnesworth Member

    Chipping Norton
    Chlorine and chloride are very seperate and distinct chemically. Chloride is a necessary part of all life. Chloride shouldn't cause a problem.
  11. DrWazzock

    DrWazzock Member

    They used MOP to firm up clay subsoils when building runways during the war.

    I would expect some clay soils to have huge reserves of potash, but I doubt light sand has much to release? Opposite applies to phosphate. On our sand we struggle to get phosphate levels below 3, but potash 0 to 1.5.

    Maybe the opening of the poly halite mine up in N Yorks or somewhere will be the answer.
  12. Really? You got on any info on that?
  13. martian

    martian DD Moderator

    N Herts
    I'd heard that about the aerodrome runways too. Something to do with the KCl binding the clay platelets very tightly together.
    We haven't put any K fertiliser on most of our fields for years and the index keeps rising (whenever we do a conventional test) but as it seems the testing is flawed, perhaps that doesn't mean much. It is reassuring though to read some research that backs up a hunch...quite unusual too, to get some that tells you that you don't need to spend money!
  14. Tissue test should satisfy as to whether the plant is getting what it needs. Though it will always be slightly short of k at stem extension I guess
  15. York

    York Member

    knowing is oposite of guessing, I guess.
    p.s. after a eveing out with the Top Twins in KiwiLand
  16. Knowing is not the opposite of guessing. Not knowing is the opposite of knowing. Guessing could be right or wrong. But I used the word because I was introducing a supposition because I did not know whether Martian already does correlate tissue tests with soil tests and so wasn't in a position to definitely say so.

    Careful you don't wet the bed now after all that beer.
  17. martian

    martian DD Moderator

    N Herts
    Now, now you two.
    Good guess though Will, I am a bit of a novice at tissue tests, but the few we've done are very revealing (in conjunction with Albrecht soil test...)

  18. What did you learn with the tissue test?
  19. martian

    martian DD Moderator

    N Herts
    Errm...low in Potassium (and N and P and S and Zn and Boron) Apart from that, ok!
  20. matttargett4

    matttargett4 Member

    K is a cation, hence it binds clay colloids, however it doesn't flocculate soil like ca, it makes cement, we have acres of the stuff.

    Cl sterilises soil life, I forget the numbers but it's only a few hundred pounds per acre in one go to deliver enough cl to kill all life.

    Crops draw k from the air, if you don't remove stover the levels should rise in time supposing it isn't leaching too fast to keep up.

    Or so I'm led to believe


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