Apart from the obvious cost implications are there any big negatives to applying excess Sulphate sulphur? Just looking at juggling various different ferts for another year and am getting 'free' sulphur. I know its very leachable so must be a pollution risk? Still applied at lower rates than N for example. Twice recommended cereal dose is only 60kgs SO3/ha. What effect would it have on soil life? Anything else to think about?
Excess Sulphur
- Thread starter Flat 10
- Start date
As above recommendation is about 30kgs/ha and I was thinking about maybe 60/ha
- Location
- S E Glos
Excess S can acidify the soil so a possible issue if your soil is already acid. This has been a concern with close OSR rotations, given the amount of S they need.
Also, the N:S ratio in the crop could be unbalanced, I suppose. This is more important then S content in the crop, per se.
Also, the N:S ratio in the crop could be unbalanced, I suppose. This is more important then S content in the crop, per se.
- Location
- the brecks norfolk
You'll be fine , that's not a massive amount.
My osr gets 88kg/ha but this year I whacked it up to 120kg/ha just to see and I may have cocked up the spreader settings:whistle.
All cereals get 60kg/ha and have done for several seasons now. it's give or take a 1:3 ratio which I think is about right, it's slightly over that on barley and slightly under on wheat but it keeps things simple and I definitely think it pays off.
I'm not aware of any antagonisms with excess sulphur beyond soil acidification. I'm led to believe that it is good for releasing locked up phosphate from calcareous soils. Normally, the cost of S means few deliberately overdose it. I've done variable rate kieserite on osr which gives some massive doses in places and not seen any crop effect.
- Location
- the brecks norfolk
For my rate of so3 in cereals it's only £7.50 acre and I get 14 units K and some MG thrown in too.
You are using polysulphate then?
I use 32% N 9.4% SO3, so just under 3:1 on everything. That's 70 kg SO3 on wheat and 64 kg on osr. Kieserite top up on osr, otherwise it might not be enough. manures or sewage are also bonuses for S.
Edit: Around 3.4 to 1 ratio, not less.
Edit: Around 3.4 to 1 ratio, not less.
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So 48 units of S per acre? I deal in elemental here, that would be ideal amount in my opinion
I believe we don’t use enough and often use that much on cereals
WOSR gets more
Fish
Member
- Location
- North yorkshire
All winter wheat/rape here gets 500ltrs of a 21n - 7.5s, that's s not so3, so around 92 so3.
- Location
- the brecks norfolk
Your confusing units/a.c. with kg/ha both are so3.
Flat 10s 60kgha needs dividing by 2.25 to get back to your elemental S
Flat 10s 60kgha needs dividing by 2.25 to get back to your elemental S
Fish
Member
- Location
- North yorkshire
Sorry, not confused at all, I'm home mixing urea and ammonium sulphate, ams contains, as I'm sure you are aware, 24%s or 60 as so3.
- Location
- the brecks norfolk
My reply was to Phil's post.
Depends on final N qty which varies a bit between variety and soil type but yes 3:1 mean most of our wheat would see 70-80kgs SO3
Fish
Member
- Location
- North yorkshire
Apologies
Yes I see folly of my ways
Bogweevil
Member
Sulphate won't acidify soils is applied in compounds with bases, gypsum, kieserite and sulphate of potash for example. Acidification will take place if elemental sulphur or compounds with ammonium ions are used due to the formation of acids and free hydrogen ions.
Never heard of sulphur/sulphate being harmful to plants - commercial tomato growers use much sulphate of potash and sulphate of magnesium (epsom salts) in hydroponic systems with no ill effects.
Never heard of sulphur/sulphate being harmful to plants - commercial tomato growers use much sulphate of potash and sulphate of magnesium (epsom salts) in hydroponic systems with no ill effects.
- Tags
- magnesium variable rate