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How to correct twin disc pattern cock-up?

Discussion in 'Cropping' started by Feldspar, May 3, 2016.

  1. Very irritating afternoon. Did a tray test this afternoon behind our twin-disc spreader applying Nitram at 24m and 375 kg/ha. Had this spreader tested by a specialist firm and had it set up well on Nitram two years ago (didn't use it much last year). Today this was the result (far left at 0m from tramlines, next to the right at 4m, next at 8m and furthest right at 12m from the tram-lines):
    2016-05-03 18.51.20.jpg

    We did another tray test using a different bag, with a different amount in the hopper, after checking the settings and on both sides of the tram-line and got the same result. How can it be this far out?!

    The scale on those Amazone gauges is non-linear which I find a bit illogical. Anyway, it's clear that we were applying at least twice as much behind the spreader compared 8m out from the tram-lines. I'm kicking myself, but I only did this test after we've done quite a few acres. The question now is how the hell to correct this cock-up?

    It will probably mean that our total N rate so far various between 180 and 220 kg/ha. Should we just bump the late N dose for protein up by 20 kg/ha and accept the variation, or should we try and tweak the spreader so that it applies more in the middle of the tram-lines and less behind the tractor to try and compensate? Another idea is to get some liquid fert and apply in bands where the rate was lower.

    The few tray tests I did last year were always an annoying amount out - never less than 5% variation and often quite a bit more. With our newer spreader you take readings off the gauges, put the values into the computer and adjust the discs accordingly. Did that for Nitram last year and even after the correction I had to recorrect.

    All this has convinced me that we're going to switch to liquid fert asap. I don't care what the price difference is - at those levels of inaccuracy there can be no argument. We were using high quality expensive solid fertiliser, new vanes on the spreader and very light wind.
     
    Last edited: May 3, 2016
  2. Fuzzy

    Fuzzy Member

    Location:
    Bedfordshire
    I would try and tweak the spreader. Were you really applying 375kg/ha? or 75?
    Ideally the shorter vane needs replacing with a longer version.
    Even if it takes you a day fissing about with the spreader to get the totals correct it is probably the easiest way to sort it.
     
    Brisel likes this.
  3. Badshot

    Badshot Member

    Location:
    Kent
    Leave it as it is and drive in between the tramlines with very narrow wheels on.
     
  4. 375 kg/ha of product (129 kg/ha of N). I think you're right though. I'm going to enter false values into the Amatron 3 box on the other spreader to get it to help me guess what vane settings to start with to produce an uneven but inverse pattern to correct.
     
  5. That was another suggestion. We have got row crops which are pretty narrow. Rather embarrassingly we've done 300ac or so like this. Kicking myself for thinking it would be OK from the previous year and not checking before we started.
     
  6. But doing that though won't sort the problem with the same settings because we can't apply another 375 kg/ha to make it totally even!
     
    Badshot likes this.
  7. Badshot

    Badshot Member

    Location:
    Kent
    To be honest I think it'll be the simplest solution. The wheat will stand up again anyway with only one pass over it.
     
  8. Badshot

    Badshot Member

    Location:
    Kent
    It's been a long few days, I'm not sure how you will make it completely even, just even it up a bit and put it down as a life lesson.
     
  9. DeeGee

    DeeGee Member

    Location:
    North East Wales
    Used to use liquid many years ago with success until our contractor let us down one year about a week before he was due to spread the stuff. Would go back to liquid tomorrow if I could guarantee the supply and a good contractor to put it on; so much better than granular spreading in terms of evenness of application on border cut off etc.
     
  10. Hampton

    Hampton Member

    Location:
    Shropshire
    Can't remember quite how you do it, but i think if you press scales and C together the pulses should open to 1500 on each side.
    If you walk around the back of the spreader both slides should be on 40-41.
    If they are different you need to adjust them so they both read those numbers.
    Found this out earlier in the year when ours was putting different amounts through each side.
     
  11. Happy

    Happy Member

    Location:
    Scotland
    I wouldn't go tramping through between the tramlines at this late stage.
    Would think if you went over next time with the spreader set for 30-32m then it would even it out as well as you can.
     
  12. my local scs tester has adjusted settings to fill in the pattern where the first does was uneven

    I will check every different batch of fertiliser every year because fertiliser can vary from year to year

    the amozone test kit gives the same setting as scs when tested side by side
     
  13. KennyO

    KennyO Member

    Location:
    Angus
    Remember that the spread will throw past 12m or are those measurement after going up and back next tram?
     
    Flat 10 likes this.
  14. Yes, already had that problem on the newer spreader. Had to buy a little tool from Amazone (at great cost as usual) to check the spacing. This pattern problem has happened with the older spreader.
     
  15. Happy

    Happy Member

    Location:
    Scotland
    That's been a problem on Amazone spreaders since the year dot.
    Old fashioned non variable/weigh cell ones told you to put something like an 8mm drill bit through the apeture opening on a set setting and then adjust to get same slide setting on each side.

    Amazone must have worked out if you can afford a fancy all singing all dancing spreader then you will stretch to a bit more for an expensive little tool to cure their design flaws.

    Glad I've just got a bog standard Kuhn Axis now. Not that much to go wrong, Linear scale settings and seems to be far more forgiving if set slightly out.
    All with no buggering about adjusting vane settings;)
     
    Renaultman, Colin, Refco and 2 others like this.
  16. DieselRob

    DieselRob Member

    Location:
    North Yorkshire
    Is it a za-m spreader? Increasing the short vane position will throw the fert away from behind the tractor but by how much to adjust it would be trial and error, was your machine set level? Never had any problems with blue bag spread patterns personally, did the fert look in good condition?
     
  17. Flat 10

    Flat 10 Member

    Location:
    Fen Edge
    I am surprised that things can vary that much year on year. Can anyone explain why that should be? In other words are we 100% sure that nothing has changed on the spreader?
     
    Chae1 likes this.
  18. Hampton

    Hampton Member

    Location:
    Shropshire
    We altered it by moving the sliders.
    What is this tool you are talking about and where does it go? Not heard of it before?
     
  19. sleepy

    sleepy Member

    Location:
    Devon, UK
    It looks almost as if one of your discs is applying massively more than the other. The tray on the tramline is very full, the other three are fairly similar.
    Was one side of the spreader emptying before the other?

    You could do with doing a proper tray test, 12 trays spaced out evenly between two tramlines. Drive up one tramline and back down the other. Weigh them all and see what the full spread looks like.
     
    JDJ, General-Lee, Jim75 and 2 others like this.
  20. Oilseed

    Oilseed Member

    Location:
    North Cambs
    I would put it right with liquid, blank off jets where sufficient has been applied and use different sized nozzles as required across the boom width.
     
    snipe, Clive and Brisel like this.

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