ANOTHER soil test thread....

Brian

Active Member
I had a soil test run in 2014, shortly after I purchased my property. I applied lime at the recommended levels and have been fertilizing as recommended for the last 3 years. I just re-tested and need some help interpreting the results and working up a strategy to continue building my soil. I'm making progess but still have a ways to go.

Here are the results for 2014 and 2017:
Soil test results.jpgThe easy part is that I need to reapply lime in "Boonie."

My phosphorus (P) level has increased but potassium (K) has barely moved. I've been planting a wheat and oat mix for the last 3 years - would switching over to rye help build up my K level?

My sodium (NA) level is up in both plots, which I assume is a function of 3 years of fertilizer application - correct? Are these numbers anything to worry about?

Both calcium (CA) and magnesium (MG) went up - and the CA went up dramatically. What could cause this and is it anything to worry about?

If you see anything else in the soil report results worth noting please let me know - this is all new to me!

Thanks,
Brian
 

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It can get a little complicated and others on here can probably add much more to this, than I, but, for me the most important number on the report is ph and you are improving that by adding lime (I assume dolomitic pelletized lime?). However, dolomitic lime is made up of calcium carbonate AND magnesium cabonate. Hence the higher calcium (which is good) and magnesium numbers. Calcitic lime is just calcium carbonate. Use that, if you can find it or ask some farm stores what their analysis of regular AG, powdered lime is and have them apply it , if you have enough acres.

Acidic soils "tie up" P and K, so the higher ph you go, the more becomes available. Sodium, probably from the fertilizer.

Now, I do soil test, primarily to keep a check on my ph. I don't fertilize "per" the soil test, because I am not raising a crop and my budget doesn't allow for it, but I probably go 50% of the recommendation. I do and suggest you consider, adding daikon radishes and clovers to your mix. Radishes have a deep tap root, that will pull nutrients from deep in the soil, up to the soil surface, for your next crop. They also break up hard pan, add organic matter and my deer really like them.

Medium red clover, also might go 3 feet deep in to the soil, doing the same thing as the radish, but also "making" nitrogen fertilizer, to be used later. Other clovers will do similar things.

Cereal rye is a good scavenger of nutrients as well!

Acidic soils.JPG Cover crop advantages.JPG Nitrogen in clover.JPG
 
Even though you have two pieces of paper with a lot of data there still are a lot of unknowns. I've said it often and one more time won't hurt. It's really difficult to get a soil sample representative of the area being planted. It's even more difficult to replicate that sample three years after the fact.

Three years is a good spread for collecting sample, but I will often do every other year on new land.

It's the tendency in nature for all things to revert (or at least try to revert) to the natural condition. Soils are no different. Nutrient levels and pH are determined by the parent rock from which the soil is derived....that plus the organics that decompose in it. Apply amendments, but they won't last forever. While ions can be tightly bound to soil particles, it's only for a while. The major properties of soil are texture, structure, consistence, color, permeability, and temperature. All these will determine how long you get to keep your soil amendments like lime and fertilizer.

Just something else to consider.
 
Your CA is way up in both plots, which is why your pH and CEC have both improved. Increase the K and Mg (be SURE you're getting dolomitic lime!) and you'll raise the CEC even more. It's too bad they didn't test for OM% because that would help tell the story of where you started, where you are, and whether or not what you're doing is going in the right direction.

In a nutshell: You're doing a good job, but the K you're applying is only sufficient to the growth of what you've planted, so you're not seeing any buildup of potassium in the soil. Double up with some potash this year. The reason you need to INSIST on dolomitic lime is that you have a very high Ca/Mg ratio and need more Mg to help bring that back in line. I'm almost positive you used calcitic lime last time, which is why the Ca jumped up so much, but doesn't explain the small increase in Mg.
 
I'm betting you've got nutrient tie up due to excess calcium. A more complete test would help. But if I had to guess, I would say you may have a drainage problem or little to no sulfur. On your Boone plot I'd put on 1 ton of dolomitic lime as mentioned. Sourcing it is the hard part. Waukesha from Tractor Supply is 19% calcium, 12% magnesium. While that will add calcium, it will bring down your calcium saturation.

Look in your area for a product called K-Mag, and see if it's affordable. It's a compound of potassium magnesium sulfate. I've never seen it in the midwest, but somebody must make it somewhere.

If you're dealing with any kind of significant acreage (over 1 acre), I would spend the money on a more complete soil test before you get to buying more soil amendments. I don't know Mississippi weeds, but some feedback on what was growing there when you started, as well as an opinion on whether it drains may help troubleshoot it further. Sulfur parts per million would also tell us if you have a drainage problem. Here's some info to help you make sense of all this stuff.

http://www.mosaicco.com/documents/K_Mag_Granular.pdf

 
I'm going to stay more simple. I started with ph of 5 and have kept that at 6.5-7 since first application of lime 8 years ago. And I have typically poor soils although maybe not as sandy as yours might me. All my nutrient readings stay at VH levels, OM is 5, CEC is 16+. Now I cant take credit for any of that except in the early years I made sure to do the LC rotations. I think you need a good grain, my choice is WR for soil inmprovement, and good legume clovers that make N. Rotated with brassica that bust the soil, add nutrient as they decay, regardless of whether your deer like them or not. Now with this combo, you add amendments, improve OM and CEC, and your soils maintain their health with very little imput from you. All these efforts are cheap and can be applied with high dollar tractors or simple spreaders and a dragged bedspring and yard sale roller as I began. I like wheat, and I like Oats, but without the other I think improvements will be slower.
 
Thanks for all the information guys, I don't know if I will ever get to the soil levels I would like, but I really want to improve my soil as much as possible.

Here's a little more information on my property: I purchased in January, 2014 and before that it was a Plum Creek pine plantation that had been clear cut 2 years earlier. I believe the plots had a single planting - probably rye grass - the fall before I purchased. The soil is a light textured silt loam (loess) with no noticible drainage issues. It was a chore to disc it the first year, but has turned over nicely since, which has allowed me keep discing to a minimum. I had the co-op spread ag lime at the recommended rates in 2014; I have no idea on what they were spreading, but the soil test clearly show it was heavily weighted to calcium. I will be using pelletized dolomitic lime this fall. I've planted a mix of wheat and oats for the past 3 years. I was already planning to add brassicas (radish and rape) this year and now I'm going to replace the wheat with rye at about 50# per acre (plus 35# oats). I added crimson and arrowleaf clover two years ago and it has reseeded reliably.

I follow most of what has been said above, but I was so focued on the fact that the current soil test lists MG as "H+" that it never dawned on me that I might need more. I checked and K-Mag is available in this area- I'm going to look into using that instead of 0-0-60. Can someone give me an idea of what I would be shooting for in a CA:MG ratio? If I'm doing this right its about 23:1 in the Bluff plot and 16:1 in Boonie. I've seen information on this, but it was always identified in saturation levels, not # of extractable nutrients which is how its reported on my soil sample results!
 
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Can someone give me an idea of what I would be shooting for in a CA:MG ratio? If I'm doing this right its about 23:1 in the Bluff plot and 16:1 in Boonie. I've seen information on this, but it was always identified in saturation levels, not # of extractable nutrients which is how its reported on my soil sample results!

That's the hard part. I don't think the math is quite as simple as weighing your ppm of the five elements as a percentage of their sum. It can give you an idea, but that's about it as far as my capabilities go.

I wouldn't give up. If you had a coop come out and spread, you must be dealing with multiple acres. You can get a complete soil test for $30-35/each. You're going to be light years ahead with clear information, and you'll get that back in clarity of what you need and don't need. Once you have clear info, a good ag guy, or some here can help whip up a recommendation in a minute or two. Here's one of my tests, and my thought process below.

plot.PNG

1. pH is 5.8, not terrible, but should come up. I need lime.
2. Buffer pH is rounded up to 7. Means 1/2 ton would get me in the zone, one ton probably better.
3. I do a rough "re-weighting" of the base saturation numbers by removing the hydrogen and recalculating the ratio of the other 4 to 100%. That shows me I have room to raise my calcium. We'll come back to this in a second.

4. I have 21 ppm sulfur. Not bad by any means, but it indicates I've got a drainage problem cause it isn't coming from the sky anymore. It's obvious upon physical inspection, but verified by the fact a leachable nutrient isn't leaching.
5. Because I've identified a drainage problem, and I have room to bring up my calcium, I'll use a calcium-only lime to help create pore space in my soil. Probably won't aleviate the drainage problem completely, but I won't make it worse by mistakenly adding magnesium with the wrong lime.
6. I want 6% potassium. Ideal is 4-8%. Below 4 it can get tied up. Above 8, it'll tie up other things. So I put on a lot of 0-0-60.
 
I follow most of what has been said above, but I was so focued on the fact that the current soil test lists MG as "H+" that it never dawned on me that I might need more. I checked and K-Mag is available in this area- I'm going to look into using that instead of 0-0-60. Can someone give me an idea of what I would be shooting for in a CA:MG ratio? If I'm doing this right its about 23:1 in the Bluff plot and 16:1 in Boonie. I've seen information on this, but it was always identified in saturation levels, not # of extractable nutrients which is how its reported on my soil sample results!

Imagine soil as a chain, with a variety of different link types in it. To make a complete chain you need to have "x" number of each type of link, plus numerous master links, where the other types join up. In your situation, you have too few link for K and Mg to make as many chains as you would like to make, so all of the other links are there, but not part of a usable chain. If you spread around a bunch of K and Mg links into your soil, you have enough Ca links to build a lot more chains. (This is a crude way of understanding CEC, which is a far better indicator of soil health than pH.)

The great news is you've made good headway! Your sizable increases in CEC are what you should focus on, with anything approaching 10 being a soil you can really work with. When you apply some dolomitic lime and a heaping helping of potassium, you're going to see even more improvements in that number, which means healthier plants and more nutrient delivery to the deer and other wildlife that frequent your food plots. :)

To answer your earlier question: With lower total values, a Ca/Mg ratio of 6:1 to 12:1 is pretty solid. When you have ample amounts of one or the other, the ratio is less critical, so long as you amend such that you have ample amounts of both. Your starting ratios were 3:1 - not enough Calcium. You had calcitic lime applied and increased the Ca dramatically, but now you need to bring up the Mg numbers to help restore that ratio. (Keep in mind that dolomitic lime still has more Ca than Mg, so you'll increase the Ca even more, but bring the ratio back into balance by applying it.)
 
What was the price you found on K-Mag? Up in my country, most guys haven't even heard of it.

I had to look around to find it but found some about 40 miles out of the way at $18.50 per 50# for the granulated K-Mag. Right now I'm think of using K-Mag at 200#/ac in addition to triple 13.
 
One other idea to consider:

On Bluff: Skip the triple 13 altogether. You've got enough P that you can ignore it for a year or two. If you plant a mix of legume/grain you could skip the nitrogen too. Instead, use the extra fertilizer money for more K-Mag.

On Boone: Go with potash (0-0-60) and dolomitic lime. Don't use any K-Mag here. Also skip the triple 13 and buy more potash.

You think the K-Mag dealer would throw you a discount if you bought a bigger quantity?
 
One other idea to consider:

On Bluff: Skip the triple 13 altogether. You've got enough P that you can ignore it for a year or two. If you plant a mix of legume/grain you could skip the nitrogen too. Instead, use the extra fertilizer money for more K-Mag.

On Boone: Go with potash (0-0-60) and dolomitic lime. Don't use any K-Mag here. Also skip the triple 13 and buy more potash.

You think the K-Mag dealer would throw you a discount if you bought a bigger quantity?

I think I follow your logic here. How much K are you suggesting per acre? Is K 'bankable?'

These are small enough plots that the cost isn't too much of a factor (Boonie is 1.5 acre and Bluff is 1.) My goal is to get these plots to the point that I can manage with rotations of cover crops (luckily that's not inconsistent with food plotting!) and cut back on added fertilizers like dogghr described. The tough part is that I'm starting with some pretty crappy soil - the soil itself isn't that great and it was a pine plantation - so I'm still trying to build a solid foundation.
 
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I think I follow your logic here. How much K are you suggesting per acre? Is K 'bankable?'

These are small enough plots that the cost isn't too much of a factor (Boonie is 1.5 acre and Bluff is 1.) My goal is to get these plots to the point that I can manage with rotations of cover crops (luckily that's not inconsistent with food plotting!) and cut back on added fertilizers like dogghr described. The tough part is that I'm starting with some pretty crappy soil - the soil itself isn't that great and it was a pine plantation - so I'm still trying to build a solid foundation.

It is absolutely bankable. There's concern for soils below 10 CEC, that they could leach K. I'm operating with CECs around 8. I'm testing mine as we speak. I put on 600lbs of potash/acre in August. Only way I'll know if I'm holding it is to test again around July. On Boone, I'd try up to 750 lbs (500lbs/acre), along with your lime and test again a year from now. That would about triple the K levels in your soil.

You also don't have to bite it all off in one year. It's much easier if you can find a coop that that'll sell you bulk at bulk rates. I cut a plastic 55 gallon barrel in half made two tubs out of it. That held around 500 lbs.
 
I think I follow your logic here. How much K are you suggesting per acre? Is K 'bankable?'

These are small enough plots that the cost isn't too much of a factor (Boonie is 1.5 acre and Bluff is 1.) My goal is to get these plots to the point that I can manage with rotations of cover crops (luckily that's not inconsistent with food plotting!) and cut back on added fertilizers like dogghr described. The tough part is that I'm starting with some pretty crappy soil - the soil itself isn't that great and it was a pine plantation - so I'm still trying to build a solid foundation.

I know a bunch of guys who would trade with you in a heartbeat! What you're working with wouldn't make a farmer very happy, but the three years of effort you put in is definitely paying off. At this stage, your soil is not what I would think of as "crappy" at all...it's pretty dang close to being somewhere between good and very good. Perhaps more to the point: What do your plots look like? The plants will tell you a lot about soil quality all by themselves. :)
 
Thanks for all of the guidance. This weekend I put down 350# of K-Mag in the 1/2 acre field, which is 154# K2O and 77# Mg per acre. I also spread a ton of pelletized lime in the 1 acre plot which should help my Ca/Mg ratio in addition to my ph and will add 250# of 0-0-60 when I plant next month. I'm going to retest next year and will post a follow up (assuming I remember!)
 
I started this thread two years ago and wanted to post my latest soil test results:
Soil Test Results.jpg
My numbers are generally moving in the right direction - some more than expected, others less - but a couple of the reported figures shifted so much that I'm questioning my technique for gathering soil samples. It looks like I need to continue working on P in the Bluff plot and K in NoLad plot.

But what really surprised me was that CEC dropped across the board - is this normal?
 
Are you discing, roto-tilling or (please, no) plowing? Your organic matter numbers are pretty low and that would be the first thing I would address. Winter rye during the cold season and either buckwheat or sunhemp during the warm season would help get you back on track.

The consistent numbers from the "Boone" plot suggest you're doing well and sampling correctly, but that makes the numbers for "NOLAD" even more confusing. I would be inclined to test that plot again to see if those readings are misleading. If they come back the same, you desperately need to increase the OM in that plot.
 
I started this thread two years ago and wanted to post my latest soil test results:
View attachment 16885
My numbers are generally moving in the right direction - some more than expected, others less - but a couple of the reported figures shifted so much that I'm questioning my technique for gathering soil samples. It looks like I need to continue working on P in the Bluff plot and K in NoLad plot.

But what really surprised me was that CEC dropped across the board - is this normal?

Soil sampling is a real hit and miss proposition. Truth be known, every square yard of a field can produce different results. Did you control depth of sampling? For example, in 2014 did you test 4 inches deep and in 2019 did you go deeper? Any ideas? Do you use a soil tube or a shovel? In your sample, are you including the organic material at and on the soil surface, or, do you shove that aside before you container your sample?
 
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