Anyone out with N

[Grass And Grain]

I did 3. Can see diff where I didn't use it. I think you need approx 6kg/ha (rough calc in my head) to give a 2% solution

Was that just prilled AN you used?

 

[robbie]

150 l/ha is 150 kg. That’s the easy bit. 6.5 kg urea I think.

150lt = 150kg. 1% of 150 is 1.5kg, 2% would surely be 3kg?

Edit. At 46% need twice as much so roughly 6kg is that correct.

Also a 2% solution is that w/w or w/v there's things confuse me because I've never had anything to do with liquid fert.

 

[Shutesy]

150lt = 150kg. 1% of 150 is 1.5kg, 2% would surely be 3kg?

But the urea is only 46% N not 100% N so roughly double it to 6kg

 

[ollie989898]

I suspect it is the other way around, Mn facilitates the uptake of nitrogen. Certainly if I had a crop which was unhappy and going backward I would be more ready to get a sprayer out.

 

[Chae1]

Im a cynic but find it hard to believe 3kg/ha of urea is going to make any difference.

 

[Simon Chiles]

Maybe we are being too keen. I wonder if anyone has any comments on this slide from Neil Fuller I saw a while back. On high CEC clay soils with a lot of negative cation capacity, i think the NH4+ ions will be fairly strongly bound and hence not that leachable. Crops have established very well and will have larger root systems than average I am assuming.
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I thought Neil said that crops needed P in the first 40 days of growth, to me that means you’re about 3 months too late and not therefore going early as your posts suggest.

 

[Feldspar]

Foliar nitrogen- in the plant before a ditch...

I just don't see the point of applying something the crop is largely not going to make use of for a time. I think what others have said holds true: time for a winter yet.

In manganese products they are often in the Mn nitrate/sulphate forms so your crop is getting a tiny dose of goodies with it.

One reason could be the scenario where things stay wet but the weather warms considerably. Then on heavy land you can't get on to put the fertiliser on but your crops then want it. You can then make a mess of your tramlines, and even if prepared to do that it sometimes isn't practical, or wait and lose potential. Not exactly unheard of. One of Neil Fuller's other slides said that wheat will uptake ammonium ions at a soil temp of 4 degrees. One of my friends not too far away measured 5 the other day.

 

[Flat 10]

One reason could be the scenario where things stay wet but the weather warms considerably. Then on heavy land you can't get on to put the fertiliser on but your crops then want it. You can then make a mess of your tramlines, and even if prepared to do that it sometimes isn't practical, or wait and lose potential. Not exactly unheard of. One of Neil Fuller's other slides said that wheat will uptake ammonium ions at a soil temp of 4 degrees. One of my friends not too far away measured 5 the other day.

But you would expect there to be sufficient N in the soil for a while yet

 

[Brisel]

150lt = 150kg. 1% of 150 is 1.5kg, 2% would surely be 3kg?

Edit. At 46% need twice as much so roughly 6kg is that correct.

Also a 2% solution is that w/w or w/v there's things confuse me because I've never had anything to do with liquid fert.

At that kind of dilution it shouldn’t make a significant difference to specific gravity, so don’t complicate things further! Most of it won’t be intercepted by the small crop canopy at this time of year but end up in the soil.

Please leave a plot untreated and let us know how it goes.

 

[Brisel]

Difference between NO3- and NH4+. There are no Ammonium Vulnerable Zones. Although it will convert, this process is very slow at this stage IIRC. People always like to forget the difference. I recall @York doing some German trials where they put ammonium sulphate on in the autumn in quite large amounts on heavy high CEC soils and could not measure any appreciable leaching over control.

Have you got a link to evidence that the nitrase enzyme conversion of ammonium to nitrate is slow please? The nitrate is much more leachable.

 

[Feldspar]

But you would expect there to be sufficient N in the soil for a while yet

Lower rainfall overwinter would tend to increase SMN. Crops are quite forward and so might have taken up more up than normal. Depends what the predominant form of N is in the soil. If it's mainly nitrate then that won't be ideal because ammonium could be taken up at lower temps if NF is right.

Just from what I've seen, early N often supports growth at much earlier times that I would have guessed. We always struggle to get sufficient ear numbers and crop biomass and historically that has been because I think we have been too slow to get nitrogen on in the spring.

 

[Flat 10]

Lower rainfall overwinter would tend to increase SMN. Crops are quite forward and so might have taken up more up than normal. Depends what the predominant form of N is in the soil. If it's mainly nitrate then that won't be ideal because ammonium could be taken up at lower temps if NF is right.

Just from what I've seen, early N often supports growth at much earlier times that I would have guessed. We always struggle to get sufficient ear numbers and crop biomass and historically that has been because I think we have been too slow to get nitrogen on in the spring.

I think there’s a point in saying that earlier N may support more growth, but overall it doesn’t increase yield and increases leaching so not a good thing. Perhaps you have been way too late with your N.

 

[Simon Chiles]

Lower rainfall overwinter would tend to increase SMN. Crops are quite forward and so might have taken up more up than normal. Depends what the predominant form of N is in the soil. If it's mainly nitrate then that won't be ideal because ammonium could be taken up at lower temps if NF is right.

Just from what I've seen, early N often supports growth at much earlier times that I would have guessed. We always struggle to get sufficient ear numbers and crop biomass and historically that has been because I think we have been too slow to get nitrogen on in the spring.

You need one of these, otherwise everything is just guesswork. To be honest even with one the results can be surprising. The only thing I can definitely say is that the sap N level in the grass on my lawn is always far superior to any crop in a field, something I always suspected.

 

[Feldspar]

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You need one of these, otherwise everything is just guesswork. To be honest even with one the results can be surprising. The only thing I can definitely say is that the sap N level in the grass on my lawn is always far superior to any crop in a field, something I always suspected.

You said the results are very hard to interpret.

 

[Flat 10]

View attachment 759348

You need one of these, otherwise everything is just guesswork. To be honest even with one the results can be surprising. The only thing I can definitely say is that the sap N level in the grass on my lawn is always far superior to any crop in a field, something I always suspected.

What do you put that down to?

 

[Simon Chiles]

You said the results are very hard to interpret.

The sap N yo-yos up and down according to temperature, timing of N application etc and it’s difficult to work out a pattern of what’s actually happening. However it will tell you at any given time the amount of N present in the sap and I can tell you that the results are often very different from what you would imagine them to be, just because a plant looks yellow doesn’t necessarily mean that it’s low.

 

[Simon Chiles]

What do you put that down to?

I think it does it deliberately just to p me off as I hate lawn mowing.

Actually it’s probably down to the fact that I have a mulching mower and it’s the OM of the clippings.

 

[Feldspar]

Have you got a link to evidence that the nitrase enzyme conversion of ammonium to nitrate is slow please? The nitrate is much more leachable.

You are right to challenge me on this assertion.Need to finish a few more papers, but I think my memory may have been leading to overconfidence. Will report back once I've got a bit further.

 

[ollie989898]

View attachment 759348

You need one of these, otherwise everything is just guesswork. To be honest even with one the results can be surprising. The only thing I can definitely say is that the sap N level in the grass on my lawn is always far superior to any crop in a field, something I always suspected.

Lawn grasses= perennial and with much more extensive root systems also they will have more storage for stuff to horde over winter. A crop plant is a genetic oddity by comparison who knows what we have lost by close breeding them.

 

[jonnyjon]

Lawns that are kept short have very short root systems