Feldspar
Member
- Location
- Essex, Cambs and Suffolk
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):
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.
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.
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