# nitrogen on alfalfa



## shadyoakhay (Oct 23, 2014)

has anyone ever applied 30% liquid nitrogen to alfalfa in low doses. like 10 gal/a or less. seems like the cheapest and best nitrogen ive found for my grasses.


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## Hugh (Sep 23, 2013)

That would equal to about 3 pounds of N per acre, which is negligible, and alfalfa makes its own N in the first place.


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## somedevildawg (Jun 20, 2011)

Cheapest and Best rarely get used in the same breath.....I agree 3# is not worth the trouble even if it didn't fixate N


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## Vol (Jul 5, 2009)

shadyoakhay said:


> has anyone ever applied 30% liquid nitrogen to alfalfa in low doses. like 10 gal/a or less. seems like the cheapest and best nitrogen ive found for my grasses.


You will need some cheap diesel to go along with it to make it worthwhile....and extra time.

Regards, Mike


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## hay wilson in TX (Jan 28, 2009)

Rule of thumb is not to top dress less than 50 lbs of N/A

Now if you have a 10,000 spill, alfalfa would be good to take up that nitrogen. Better than a grass!


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## endrow (Dec 15, 2011)

Hugh said:


> That would equal to about 3 pounds of N per acre, which is negligible, and alfalfa makes its own N in the first place.


I would think 10 gallons would equal about 27 pounds of actual nitrogen


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## Hugh (Sep 23, 2013)

endrow said:


> I would think 10 gallons would equal about 27 pounds of actual nitrogen


Endrow,

You are right, 27 pounds is much closer. Liquid fertilizers usually weight about 10 pounds per gallon. 30% of ten gallons would then be about 30 pounds of N.


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## PaCustomBaler (Nov 29, 2010)

Agreed, 10 pounds to the gallon is what I've always heard. You might see a negligible gain, but I've always seen a decrease in root nodulation when N fertilizers are applied. Mostly I believe because the root doesn't need to produce more nodules as nitrogen was applied by grower. Anyone correct me if I'm wrong, I'm not 100% positive on the reasoning.


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## Hugh (Sep 23, 2013)

PaCustomBaler said:


> Agreed, 10 pounds to the gallon is what I've always heard. You might see a negligible gain, but I've always seen a decrease in root nodulation when N fertilizers are applied. Mostly I believe because the root doesn't need to produce more nodules as nitrogen was applied by grower. Anyone correct me if I'm wrong, I'm not 100% positive on the reasoning.


I've heard that the alfalfa will decrease the feeding of carbohydrates to the bacterial nodules if N is applied. This will cause a reduction in the bacterial population and the alfalfa will then become dependent on applications of N. I don't know if this is fact, but it sounds reasonable. In any case, we know we needn't apply N.


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## OhioHay (Jun 4, 2008)

I believe 28% weighs 10.67 lbs per gallon. I have also heard the same thing about reduction in nodules with nitrogen applications. Heard the same thing about soybeans.


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## Rodney R (Jun 11, 2008)

3.3 units per gallon of 30% s what the fertilizer guy told me, last week. He also said that soybeans only produce enough N to get them to about 60-65 bpa.

I never thought too much about putting N on alfalfa...... What does a guy do when he has a mixed stand of OG and alfalfa or timothy and alfalfa - do you put N on for the grass? Will it actually hurt the alfalfa growth in the later cuttings if you apply no more N?

Rodney


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## Rhinoman (Dec 7, 2014)

I was told by my fertilizer guy when you have mixture of grass/alfalfa you do need to apply N because the grass robs from the alfalfa which can't produce enough for both. Which in turn will cut your production from both. I always fertilize in April and then right after my 3 rd cut have been able to maintain 2 ton acre for 5 cuttings. I hope I still can maintain this now that I have said it.


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## somedevildawg (Jun 20, 2011)

Here in the south where not a whole lot of alfalfa is grown, we have some mixed grass/alfalfa stands....during june, july, august, N is applied at a rate of 50-70 units per acre. These are dairies for the most part.....


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## vhaby (Dec 30, 2009)

Rhinoman,

Your fertilizer guy is incorrect. Actively growing alfalfa releases almost no nitrogen for the grass. This has been proven in studies using N15 to follow nitrogen release from alfalfa to the grass. Most nitrogen released from alfalfa for companion grasses comes from mineralization of nitrogen from decaying alfalfa leaves, roots, and possible stems. In an alfalfa/grass production system, livestock grazing and ultimate urination and defecation will release nitrogen from the alfalfa to the grass. In research trials conducted at Texas A&M AgriLife Research at Overton, alfalfa was seeded in rows 7, 14, 21, and 28 inches apart into a stand of Coastal bermudagrass and fertilized with 0, 30, 60, 90, and 120 pounds of nitrogen per acre per cutting. In the first couple of years, applied nitrogen improved bermudagrass yields as the rate of nitrogen was increased. In the third year, there was little bermudagrass growth and hardly no response to applied nitrogen. Alfalfa outgrew the bermudagrass regardless of the rate of applied nitrogen and had only a negligible response to the applied nitrogen. Even at the 28 inch row spacing, alfalfa outgrew the bermudagrass. That was in East Texas on a limed loamy fine sand (Darco soil) that contained little native soil fertility.


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## PaCustomBaler (Nov 29, 2010)

Rodney R said:


> 3.3 units per gallon of 30% s what the fertilizer guy told me, last week. He also said that soybeans only produce enough N to get them to about 60-65 bpa.
> 
> I never thought too much about putting N on alfalfa...... What does a guy do when he has a mixed stand of OG and alfalfa or timothy and alfalfa - do you put N on for the grass? Will it actually hurt the alfalfa growth in the later cuttings if you apply no more N?
> 
> Rodney


I apply N to A/O stands when the grass is more than 20% of the stand.


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