# Advice on when to apply boron and potash to alfalfa



## CottageFarm (Apr 30, 2013)

This is the first year on a new stand of RR Alfalfa, it was planted last fall and has established very good so far this spring. We applied a split application of fertilizer last fall and this spring including lime last fall back in October. As I went to a local dairy farmer this past weekend to check out his alfalfa he grows for his dairy cows, they were already taking a first cutting and were baling it when I was there at 50 percent moist. along with plastic wrapping the bales to be sealed off from air for curing. He was telling me every time after they cut it they put down 1 gal. of boron to the acre along with potash. I can't remember the potash amount he said but he was pressing the issue with these two products for faster green up and better forage quality. There stand is on its 4th year and they produced 8 tons to the acre last year along with 8 cuttings here in eastern Va. with no irrigation. They also have really high protein levels at 25 percent along with feed values in the 220's, of course they cut it at a early stage of growth. I was curious if anyone on here grows alfalfa and does somewhat of the same type of program with boron and potash threw out the entire hay season. Granted I am growing alfalfa to sell out right to who ever wants it so I don't want this much protein or need this much feed value. I'm looking for 17-19 percent protein and RFD of 170-190


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## Vol (Jul 5, 2009)

Do a soil test and specifically have it tested for Boron in addition to the others and it will tell you precisiely what you need. I have not heard of adding Boron after EVERY cutting but I am not saying that it is the wrong thing to do....I just have not heard of it.

Found this and it is from Purdue.....one of the top Ag schools in the country IMO.

http://www.agriculture.purdue.edu/aganswers/story.asp?storyID=5365

Regards, Mike


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## CottageFarm (Apr 30, 2013)

I had a soil test done back in the early fall after I bottom plowed the field, of course it turned over ground that has been no tilled for 15 to 20 years in rotating crops. I will see if I can find my paperwork on that test. I remember the ph was 6.6 but once I bottomed plowed it went down to 5.4.


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## Vol (Jul 5, 2009)

CottageFarm said:


> I had a soil test done back in the early fall after I bottom plowed the field, of course it turned over ground that has been no tilled for 15 to 20 years in rotating crops. I will see if I can find my paperwork on that test. I remember the ph was 6.6 but once I bottomed plowed it went down to 5.4.


5.4 ph is way too low for alfalfa....most say the lower threshold for alfalfa is a ph of 6. You need a current soil sample and test and have it tested for macro and micro nutrients that apply to alfalfa. Better get on it soon.

Regards, Mike


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## CottageFarm (Apr 30, 2013)

I'm working with a guy at crop production services to help correct the ph level as hopefully it has came up by now, it has been 6 months since we limed it to bring it up. I'm getting ready to take the first cutting this week, once that's done I will take a soil sample to get it analyed. Thanks for the advice.


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## covenanthay (Oct 2, 2009)

We apply potash after first cutting and potash, sulfur and phosphorus after the last cutting of the year.


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

I can see the idea of soil analysis is alive and well.

I recommend you pull a *hay analysis *on each cutting from each field. Use a Wet Lab Analysis to include boron, sulfur, expanding the extra elements with time.

Hay analysis first detected a copper deficiency, which resulted in a Molybdenum deficiency, that eventually highlighted a real potassium deficiency.

What works for your neighbors and friends may not be needed by you on your soils.

Selling to a Dairy use the same forage/feed testing laboratory they do. It will limit misunderstandings. NIR analysis works but the minerals reported are limited.

Just remember protein and RFV is very much dependent on the stage of growth at harvest. PLUS how good a job is done of harvesting. If your hay has a lot of leaves shattered off you will be loosing not only yield but also quality.
Rake when there is enough moisture to hold the leaves. Bale watching the relative humidity, down next to the hay.


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## CottageFarm (Apr 30, 2013)

Thanks for the advice, I have yet found a local place in Va. that does hay testing but I will shortly. I raised orchard grass last year and of course that's nothing like growing or baling alfalfa. I have learned to cut alfalfa in the evening with dew on it and come right behind it with a tedder to speed up dry time. Also same goes for raking. I plan to rake first thing in the morning with dew to save as many leaves as possible because that's what's important for alfalfa. Also I plan to cut right when the bud is at the top of the stem for the first cutting as this is what I have heard is the best time to cut first cutting.


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## vhaby (Dec 30, 2009)

In regard to determining the need for boron on alfalfa, I must take issue with the soil test for boron. A soil test of the upper 6 or so inches of soil tested for boron simply is not correlated with alfalfa response to boron- this is on sandy acid soils that have been limed to pH 7 or higher for alfalfa. First off, liming a sandy acid soil to raise the pH upward toward 7 ties up whatever small amount of residual boron was available in the soil for plant use. Second, no one has correlated a soil test of the surface 6-inch depth of soil with alfalfa response to applied boron. Testing this surface depth for boron and then attempting to make a recommendation for the boron needs of the crop is no better than a guess.

Research conducted by scientists at Texas A&M-Overton collected soil samples from the 0-2-, 2-6-, and 0-6-inch depths and analyzed these samples for boron. The only correlation that could predict alfalfa response to applied boron was hot water extracted boron from the 2-6-inch soil depth. Testing the 0-2- and 0-6-inch soil depths and attempting to relate hot water extractable boron to alfalfa response to applied boron simply did not correlate. The take-away message from this research is that the surface organic matter layer of about 2 inches must be removed before collecting the soil sample for boron analysis. Better yet, simply apply 3 to 4 pounds of actual boron per acre for alfalfa after liming an acid soil to raise the pH for alfalfa.

Also, the upper level of soil pH has been mentioned as being anywhere from 6 to 6.5 and even 6.8 to 7.0. If the soil pH is not at least 7.0, alfalfa yield will not be optimized.

Once the proper soil pH has been established, the boron has been applied, and the alfalfa is producing, perhaps plant analysis is the best way to go to determine the future boron needs for the alfalfa crop. I don't always agree with Hay Wilson, but in this case he is spot on in recommending plant analysis.


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

*I don't always agree with Hay Wilson,* but in this case he is spot on in recommending plant analysis

That is as it should be. I do not agree with what I knew for a fact just 10 years ago. A good bit of my progress I attribute to your patient tutoring.


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## CottageFarm (Apr 30, 2013)

Okay thanks for the advice as I plan on taking a sample this weekend after I bale.


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