# 46-0-0 and burning plants



## Tomas

I am wanting to get some 46-0-0 on a 3 ac. soy bean patch which was oversown with oats, wheat and brassicas two days ago. Since then, I have been under the aftermath of the storms in the Gulf, and may be for 10 more days. Is there a risk to putting down 50#/ac. of 46-0-0 on wet ground and plants? Seems to me that could blow torch everything, including my soys. What say the pros?? Thanks, Tom


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## Andy

I don't have an answer for you.....only a thank you for posting this. Our local ag store guy almost threw us out of his store for telling him we wanted to buy 46-0-0 for our foodplots! The problem with this guy is that he's a farmer planting for yield.....im a foodplotter planting for deer nutrition and tonnage.

With that said, I still recently spread straight urea (46-0-0) on our biologic maximum plots due to suggestions from people on this board. 

But I'm also dying to know.....when is the right time to use 46-0-0 and when is it not a good time?????

andy


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## Tomas

Whew, Andy! I thought I was the only one in the dark! Now if Ed, et.al. will jump in here, we will learn something. Tom


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## brokenarrow

On my instruction sheet for the mmbqdma brassica mix he tells you to broadcast 200# triple 19 and 100# 46% nitrogen at planting, Till it in and then broadcast and lightly cover seeds.


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## brokenarrow

My best guess would be ( I have done a little research but have no practical experiance) that if you have sandy soils maybe you should consider a slow release and put down right before or during a rain to minimize the burn (if useing it at all after germination) In anycase I would guess you would want it to rain imediatly after putting it down. Just my guess lets see what the experiance guys say?


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## johnhunter

A couple years ago, I planted a smallish plot of winter wheat on Labor Day weekend. I couldn't get any 20-10-10 at the time, so I went with half 6-24-24 and half, 46-0-0, and broadcast them at planting. I didn't have any "burn" issues.


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## brokenarrow

Maybe I read the post wrong (sorry if I did) I took it as the crop is growing already and he was going to broadcast on top of the green plants?


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## brokenarrow

I see why I took it the way I did?


Code:


Is there a risk to putting down 50#/ac. of 46-0-0 on wet ground and plants? Seems to me that could blow torch everything, including my soys


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## brokenarrow

This thread had made me learn a few things about nitrogen fert. This is pretty interesting?

Nitrogen fertilizers do not burn or damage plants if they are applied correctly. Fertilizers are salts, much like our familiar table salt, except that they contain various plant nutrients. When a fertilizer is applied to a soil, nearby water begins to move very gradually towards the area where the fertilizer has been applied. Salts in the fertilizer begin to diffuse or move away from the place where they had been applied. This dilutes the fertilizer and distributes it through a much larger area. If tender plant roots are close to the area where the fertilizer is placed, water will be drawn from these roots and from the surrounding soil. The more salt or fertilizer applied, the more water will be drawn from nearby roots. As water is drawn from the roots, plant cells begin to dehydrate and collapse, and the plant roots burn or dehydrate to a point from which they cannot recover. If soil moisture is limited, most of the water drawn towards the salt will come from plant roots and the damage will be severe.


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## Sofa King

Hi-
I'll weigh in on a little info on the 46-0-0 question. 46-0-0 is called Urea and is processed using nitrogen out of the air. 50 pounds of Urea is not a lot of fertilizer, meaning thats only 23 pounds actual per acre. (first number is percent nitrogen, second is percent Phosphours and the third is the percent potassium) So half of 46 is 23 pounds. 
The wrong time to put urea on is either on a hot day, over 70 degrees because the nitrogen will volitilize into the atmosphere; or on sandy soils just before a heavy rain. Urea is very soluable and heavy rains on sandy soils can leech it through the root zone before the plants have a chance to take it up. Ideally you could incorporate into the wet soils, but if you don't have equipment thats isn't an option. 
The wheat, oats and brassicas are high users of Nitrogen and should be appled once the plants get going so they have optimum use of the nutrient before it gets washed through the soil profile. Soybeans, on the other hand, are legumes and don't need the nitrogen. (although you can get a response on high production situations.)
Ideally, put that Urea on just prior to a half inch slow rain when stuff is up a inch or two.
Retired Crops Agent
In the North!


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## Archer212

Sofa King:

I just came back from the feed store. Your explanation seems to match what I was told. I was told to get it to 46, it is basically gas that expels itself quickly not unless it rains immediately on it. He recommended the granular 34-0-0, which he said should give me the same results if rain is not intimate or the 46-0-0 is not tilled under immediately. I plan to fertilize in the next week or so when my plants are 6"-8", so I am interested in something to broadcast.


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## brokenarrow

SofaKing
So what you are saying is to use the 46-0-0 on the early (small) brassicas right before a rain? No chance of damge to the plants. Is there any danger if the rain never comes? I can read all day long but its nice to talk to a real person that is an old pro at it!


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## Sofa King

Good questions on nitrogen. So what's the difference between 34-0-0 and 46-0-0? First is the amount of nitrogen, or actual nitrogen. Urea (46-0-0) is about half N, or it takes 2 pounds of material to provide one pound of Nitrogen. Ammonium Nitrate (34-0-0) takes about 3 pounds of material to provide 1 pound of Nitrogen. The plants don't care as long as they get the amount of nitrogen they need. So it comes down to what is cheaper, I guess. You shouldn't pay as much for a bag of 34-0-0 as a bag of Urea 'cause its not as concentrated. 
Next thing is the difference in the type of nitrogen or the form it is in. Urea is in the Ammonium form. Souluable and quick acting. 34-0-0 is half ammonium and half in the nitrate form. Releases at a different rate. 
Ammonium Nitrate isn't as popular as it used to be. There was a lot of it used in the Iron ore mines in the UP as a blasting agent. But when McVieh and Nichols used it in Oaklahoma City a few years back on the Federal Building, lots of places won't carry it anymore.
If the plants are up 6-8 inches tall you'll have a good canopy to provide shade and reduce nitrogen volitilization till some rain comes and takes it down. So that's good. 50 pounds of Urea or 75 pounds of Ammonium Nitrate (same N equivilants) is not gonna do much damage if the rain does't come for a while on any of the crops. And that's fine as a starter on wheat or oats. But Brassica's are HIGH nitrogen feeders and will take about twice as much nitrogen to get a good, deer attracting stand going.
Either type of fertilizer is great for broadcasting on the plants. Burn will occur if you apply large amounts , like if you spill some. But at the rates we are talking about here, I wouldn't expect to see burn even if the rain doesn't come right away.


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## Ranger Ray

I used to work with 64-0-0 on a celery farm and am here to tell you there is definitely a good risk of burn when using high nitrogen fertilizer; I have witnessed it on 2 separate occasions. And brokenarrow's info on moisture extraction is right on. Stick your hand in a bag of 46-0-0 (if you leave skin in contact for a long period of time it is capable of burning your skin) once and see how fast your hand becomes wet and slimy because the nitrogen is drawing the moisture from your hand. So my advices when using this stuff is to only buy what you think you are going to use because any ripped, holey, partially used bag will turn to concrete. Any implement you use to spread it needs to be washed immediately after using thoroughly. DO NOT leave any unused portion in the spreader implement for future use because there won't be any future use. Do not store it on concrete for extended periods of time because it can ruin it. When we applied it to the celery while it was growing we always made sure there was moisture already in the soil, and we watered immediately afterwards. The only thing I can advise as far as application rate is the higher it is the more chance for burn. I have used 64-0-0 on my lawn and have had no problem with burn but it was always very light and watered immediately. And man a little does a lot. Mow, mow, mow! Good luck.


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## Swamper

I worked with nitrogen, urea, 46-0-0 (all the same thing) for about 20 years while growing up. We would use it on potatoes, corn, and the other garden vegetables. Caution I would offer is that it will burn plants very easily if applied too heavily or conditions are very dry. For food plots, I would lean towards fertilizer to avoid the risk and expense, such as triple 12 or triple 19.

Swamper


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## brokenarrow

Now I am getting confused just a bit. I had used tripple 10 because that is all my top notch feed/seed dealer had. I put down 300# an acre. From what I was reading I was under the assumption that if I broadcast 46-0-0 and it sits on the leaves too long it will burn it. (Just under the assumption from what I was reading) I should of put it down (46-0-0) when I was planting. Anyway, is a guy better off not using it at all after the plants are 3-4 inches tall or will there be NO chance of damageing this field. 
Just when ya think your learning something by reading you get practical experiances that contradict the books. Gee ya wonder why work experiance is valuable to our college grads?

The question is: Do you broadcast over the top with 46-0-0 and not
worry about hurting the crop at all?
OR
Leave what you got do it differently next year?
This is getting good! great info!


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## Tomas

As usaual, I have gotten super information on a subject I had no experience with. Many thanks for all the input. Tom


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## Ranger Ray

> The question is: Do you broadcast over the top with 46-0-0 and not
> worry about hurting the crop at all?
> OR
> Leave what you got do it differently next year?
> This is getting good! great info!


First I want to say I am no expert. 

Because brassicas is a high moisture plant I say do not broadcast because the high moisture content makes it even more susceptible to burn. Leave what you got and look into it next year.


You can waste a lot of money for nothing on nitrogen if:



1. The nitrogen ppm in your soil is already in range for the plant you are growing. I believe the nitrogen ppm in soil for wheat in Michigan is like 9ppm's, but don't know brassicas. And too much nitrogen can make plants susceptible to disease. 



2. You loose some benefit of nitrogen to the atmosphere if you do not work it into the ground because of evaporation rate is high (there is a scientific name to what happens to it but because I am not a scientist evaporate will have to do).



I would check my soil next year to see where my nitrogen levels are at and go from there. Just my 2 cents.


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## Sofa King

brokenarrow said:


> Now I am getting confused just a bit. I had used tripple 10 because that is all my top notch feed/seed dealer had. I put down 300# an acre. From what I was reading I was under the assumption that if I broadcast 46-0-0 and it sits on the leaves too long it will burn it. (Just under the assumption from what I was reading) I should of put it down (46-0-0) when I was planting. Anyway, is a guy better off not using it at all after the plants are 3-4 inches tall or will there be NO chance of damageing this field.
> Just when ya think your learning something by reading you get practical experiances that contradict the books. Gee ya wonder why work experiance is valuable to our college grads?
> 
> The question is: Do you broadcast over the top with 46-0-0 and not
> worry about hurting the crop at all?
> OR
> Leave what you got do it differently next year?
> This is getting good! great info!


Its possible some people have had bad experiences with 46-0-0. In my "Day" I was considered an "Expert" in Field Crop Production and did some of the original work in the UP on Canola (a modified Brassica for oil production) Forage Brassicas and more recently the forage soybeans that have become popular. So I have had some experience in this field.
But let me tell you what I have done and plan to do. I planted a two acre brassica plot for deer on my farm. Planting was done about a week ago and plants are just starting to come out of the ground. I'm planning to hunt it in October and November and expect a lot of green growth at that time. To acheive this, I WILL be broadcasting 100 pounds of Urea (46-0-0) in a week or two, ideally it will be before a rain, but if not Iam not worried. Unless severe, the plants may be set back but will quickly recover. _(I've done this many times) _


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## brokenarrow

That is the kinda of answer I wanted to hear. I will do the same. I trust your words sofaking, was not doubting what your credentials were or anyones experiance. Wanted to get a solid answer on if I should broadcast or not especially from someone that has expert experiance in doing this. I will only have this one brassica plot this year and dont want to blow it now, they are coming up nicely, better than last year for sure and last year I had a very good crop!!!!. I was worried this year about the nitrogen because I did not do a sample in the field and did not know if last years brassicas depleted it, although I had clover (and alot of timothy) LOL in it that I killed and tilled under. I will broadcast this weekend when I am getting my other wheat plot ready for planting which I plan to do the next week.
This is getting good, great info thanks alot to all here and thank you sofa K.


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