# What is a optimal soil test for alfalfa



## Nate926 (Apr 6, 2014)

Just got my soil test back, just wondering what a optimal soil test would be for dry land alfalfa? Thanks in advance


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## vhaby (Dec 30, 2009)

I don't know if anyone can really answer that question, but I'll try. Soil pH needs to be 6.8 - 7.0 or higher in the surface depth. Less than 6.8 needs to be limed or risk yield loss. Lime applied to correct pH needs to be thoroughly incorporated to adequately adjust soil pH. If you had a test done for boron and then limed the soil, you can disregard the boron test result and apply 2 - 4 lb of actual boron per acre. A test for nitrate in the surface depth can be disregarded as alfalfa rarely needs to be fertilized with nitrogen. Soil test phosphorus, potassium, calcium, magnesium and sulfur need to be in the high range and then you need to apply sufficient of these plant nutrients to resupply what the alfalfa removes from the soil. Calcium applied as limestone should be sufficient, or if your soil is naturally alkaline, no additional calcium should be needed. The phosphorus can be applied in one maintenance application for the season if the soil tests high in phosphorus, or in split applications if you prefer, to resupply plant removal. Maintenance potassium can be applied after every two cuttings, and part of the maintenance application of potassium can come from KMag that will also apply magnesium and sulfur. Since you asked, I've given you my educated opinion, for whatever it is worth, based on experience on sandy acid soils in anticipation of 5 - 6 cuttings per year. I'm sure others will disagree, as there is no single best answer. Some adjustment of these suggestions will need to be made if your soil is a high clay content, high cation exchange capacity alkaline soil.


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## Hugh (Sep 23, 2013)

I agree with vhaby. I would think in a simple way about it; if the soil is not quickly drained, or if the pH is below 6.7 or so, you will have problems. I say this because many parts of Tenn have clay and very acid soils.


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## Nate926 (Apr 6, 2014)

Thanks Guys! I have 5 fields and all the fields range from 6.5-7.2 on ph. If it tells you anything I live 5miles from a city called limestone. I haven't had to add lime to any of my fields in the last 10 years.


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## FarmerCline (Oct 12, 2011)

Nate926 said:


> Thanks Guys! I have 5 fields and all the fields range from 6.5-7.2 on ph. If it tells you anything I live 5miles from a city called limestone. I haven't had to add lime to any of my fields in the last 10 years.


 You lucky son of gun.....on my fields it takes about a ton per year of lime to keep the ph where it should be. All of the fields I have were neglected for many years and it took 6-8 tons of lime to get the ph high enough to grow alfalfa. That cost a small fortune considering lime is $55 a ton spread.


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

*You lucky son of gun.*..

We all have our individual problems. Try 8,500 ppm Ca, an 8.0 pH, plus 4%-6% "free lime".

9,000 lbs/A of elemental Sulfur will wear out by the end of one season.

Find out what is good for your climate, soil, and management, and give that a try. Do not try to compete with Iowa or Georgia.

HERE corn yields about 85 bu/A which is better than our 1950's 35 bu/A.

Problem is what is adapted has no market.


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## r82230 (Mar 1, 2016)

I agree with the 6.8 to 7.0 ph vhaby.

My 2 cents is:

I lime a year in advance of seeding, giving lime time to 'work'.

My maintenance lime last year was about 1180# an acre (ph was at 6.2 on soil test).

Cost for 50 ton of lime $1200 delivered, rented spreader $200.

My soil test all come back with required / need amounts of lime, Nit., Phos. & Potash. (N-P-K).


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## Nate926 (Apr 6, 2014)

FarmerCline said:


> You lucky son of gun.....on my fields it takes about a ton per year of lime to keep the ph where it should be. All of the fields I have were neglected for many years and it took 6-8 tons of lime to get the ph high enough to grow alfalfa. That cost a small fortune considering lime is $55 a ton spread.


Yeah NC must not have any natural lime in the ground! I deliver hay in Hendersonville and was talking to a farmer there and he said he had to spread lime every 6 months to keep his ph right that was mind blowing to me!


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