P and K

Discussion in 'Cropping' started by Dave6170, Jan 19, 2019.

  1. Dave6170

    Dave6170 Member

    Location:
    Watten, caithness
    Thats the stuff that we have used on reseeds for years. But obviously not enough.
    Whats the difference between scotphos and tsp?
     
  2. Brisel

    Brisel Member

    Location:
    Dorset
    Scotphos is based on soft rock phosphate. Normally, rock phosphate makes me shout "b*llocks!" as it is virtually inert on anything other than acidic soils. I haven't seen this Scotphos before unsurprisingly as I'm near the South Coast of England but I do think it's suspicious. I've been offered GAFSA rock phosphate before and was advised to stay well clear of it on alkaline soils as I'd never see it back again, locked away for eternity.

    The marketing blurb does say it can be used for low P index soils and it is sold as a powder which will improve its availability vs a granule though you'll need a lime spreader to apply it. What is your soil pH? If it's over 7 I would avoid this Scotphos stuff. If you've got very low P levels in your soil a much more soluble version like DAP or MAP would bring levels up quickly. TSP is also soluble enough for what you want.

    http://www.originfertilisers.co.uk/products/gafsa-p-and-pk/
     
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  3. hally

    hally Member

    Location:
    cumbria
    If I want to take and send soil samples myself direct, where can I send them if I want to avoid the local agronomy company?
     
  4. clemmo

    clemmo Member

    You should be able to send them directly to any of the main labs

    Yara - Lancrop etc
     
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  5. Brisel

    Brisel Member

    Location:
    Dorset
    NRM/Cawood too. I don't think there's much difference between them all. It's quite a competitive market.
     
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  6. Dave6170

    Dave6170 Member

    Location:
    Watten, caithness
    What is Dap and map? Whats the difference?
    Local guys dont like tsp they recommend scotphos type stuff. Say it doesnt last?
     
  7. Brisel

    Brisel Member

    Location:
    Dorset
    Diammonium phosphate 18.40.0 and monoammonium phosphate 12.52.0 Very soluble and also supply nitrogen.

    Who are the “local guys?” Since I’ve got little background information here I recommend you talk to a FACTS qualified agronomist with no agenda to sell you their products. I'm not writing off materials like Scotphos if they are cheaper than straights like TSP. With the money you save on a cheaper product, you could apply a higher dose that would increase the amount available for what you need.
     
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  8. KennyO

    KennyO Member

    Location:
    Angus
    @Dave6170 are you an SAC subscriber. They will help you with all this.
    @North East Crofter might provide you with some free advice.

    I also try to use SAC for testing samples to. There is a 'Scottish' method for P analysis which can effect results.
     
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  9. Brisel

    Brisel Member

    Location:
    Dorset
    What is the Scottish method? Morgan's instead of Olsen P?
     
  10. KennyO

    KennyO Member

    Location:
    Angus
    Would need to go and look up my FACTS notes.
     
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  11. Brisel

    Brisel Member

    Location:
    Dorset
    Here's a screenshot from the SRUC website:
    upload_2019-1-20_14-27-28.png

    No mention that I can find of methodology by searching on their website.
     
  12. scholland

    scholland Member

    Location:
    ze3
    I think sruc use "modified morgans". Morgans was developed by macaulay for Scottish soils but I think it takes a while to do so isn't commercially used.
    Nrm use olsen I think.
     
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  13. Dave6170

    Dave6170 Member

    Location:
    Watten, caithness
    Yeah they took the samples and sent it off. Just want to see what folk on here say aswell.
     
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  15. Bogweevil

    Bogweevil Member

    P is P, so the material spreadable with the farm's equipment that offers the cheapest P as extractable with citric acid + water soluble would be the one to choose, no? Do the maths, yes?

    Still miss basic slag, sigh.
     
  16. Dave6170

    Dave6170 Member

    Location:
    Watten, caithness
    College are recommending tsp or scotphos to get up to a moderate level.
     
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  17. Dave6170

    Dave6170 Member

    Location:
    Watten, caithness
    It says rock phosphate/scotphos is soil acid soluable, if my ph is above 6 does that mean its not soluable or available?
     
  18. Brisel

    Brisel Member

    Location:
    Dorset
    Some will be. On calcareous soil or where continuous brassica veg is grown and pH is above 7.5 you'll be unlikely to see any of that fertiliser again.
     
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  19. Mr Charisma

    Mr Charisma Member

    Location:
    stratford on Avon
    My experience of the last few years in trying to build up P values are that the home farm which gets a lot of FYM spread on it the indexes are always there or there abouts , the land away from home gets sludge ,,,, those indexes have jumped after 2 applications over the last 3 or 4 years
     
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  20. Dave6170

    Dave6170 Member

    Location:
    Watten, caithness
    What improvements in my grass am i going to see by getting P levels up?
     

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