Fertilizer question….

[Rous14]

Looking at a soil sample (hopefully the picture posts properly as I don’t always know what I’m doing) and it shows low to very low p and k. I’m guessing my clover plot is approx 7,200 sq ft maybe a bit bigger. If I follow this it is suggesting I put approx 21 pounds of each p and k which I’m sure is probably right but just doesn’t seem like hardly much at all. What am I missing if anything? Is there anything to worry about if putting too much p or k on a plot other than possible unnecessary expense?

 

[Sligh1]

7200 sq feet calling for 21 lbs of p&k is very reasonable. It’s like 43k-ish sq feet in acre so 21 of each is a fairly high rate per acre.
I would add as much pelletized lime as u want too. Not a huge problem but if u put out a couple hundred lbs - would help. If u are able to get ahold of a mix from coop- I’d get boron, zinc & sulfur as well. I don’t see it on your soil analysis but I’d bet a nickel they are low. It’s splitting hairs & depends if u wanna get really fussy. Would help but not huge deal in end.
Yepper- looks good. Go.
& long term…. Things like drilling rye into that area, buckwheat, etc etc - any high residue plants to increase organic matter will help you too.
But yes, very simply- 21 lbs p&k - spot on.

 

[Rous14]

7200 sq feet calling for 21 lbs of p&k is very reasonable. It’s like 43k-ish sq feet in acre so 21 of each is a fairly high rate per acre.
I would add as much pelletized lime as u want too. Not a huge problem but if u put out a couple hundred lbs - would help. If u are able to get ahold of a mix from coop- I’d get boron, zinc & sulfur as well. I don’t see it on your soil analysis but I’d bet a nickel they are low. It’s splitting hairs & depends if u wanna get really fussy. Would help but not huge deal in end.
Yepper- looks good. Go.
& long term…. Things like drilling rye into that area, buckwheat, etc etc - any high residue plants to increase organic matter will help you too.
But yes, very simply- 21 lbs p&k - spot on.

10-4
i spread 125ish pounds of lime on this plot a few weeks ago. Just getting to the fertilizer this weekend hopefully. With the coop mix you reference, is boron/zinc/sulfur something that they might mix right in with the p&k youre saying? Ballpark how many pounds would you say or recommend of those should I tell them?

 

[Tmayer13]

This is a prime example of why the Whitetail Institute soil samples arent the greatest. Using your local coop who is familiar with the area is far more productive. Then you could talk to them about the micronutrients Skip is referring to.

 

[Rous14]

This is a prime example of why the Whitetail Institute soil samples arent the greatest. Using your local coop who is familiar with the area is far more productive. Then you could talk to them about the micronutrients Skip is referring to.

Yea I hear ya, it’s one of many challenges for landowners like myself that live 5 hours away in a different state though because I’m usually running down on a Friday evening for the weekend to do most of this stuff and so time is super limited, places aren’t always open on saturdays, etc…
But to your point I did chat w the local co op this morning by phone and the guy was telling me that they’ve essentially run their inventory of fertilizers and such down to nothing as they are expecting a big crash in the prices of that kind of stuff. Said corn is down a couple bucks just in last 10 days for example. Pretty interesting conversation. They rarely carry pell lime which for small food plotters like me stinks. Asked him about the zinc/boron/sulfur and he thought he might have a little straight sulfur but said that most guys use a liquid spray for those bc the plant uptakes better vs through the roots? Thoughts on that in general?

 

[Bassattackr]

Agreed w/ the others. Your plot is only about 1/6 acre. So, 21 lbs would be equivalent to about 125# / acre which is about right given how low your potash numbers are.

Also in agreement with the comments on lime. A 50# bag of pelletized lime, would be a rate of about 300# / acre which would boost your calcium numbers up some. Clovers are like beans, they need calcium, sulfur and potash.

One other important ingredients for clover plots is sulfur. Given your high Magnesium rates, this is a prime opportunity to use gypsum (calcium sulfate) as your sulfur source.

Based on your test, my inputs would be:

- 50# 6-28-28 (or 6-24-24, whichever is available) --> 84 # P / 84# K
- 50# pelletized lime
- 20# gypsum

 

[Rous14]

Agreed w/ the others. Your plot is only about 1/6 acre. So, 21 lbs would be equivalent to about 125# / acre which is about right given how low your potash numbers are.

Also in agreement with the comments on lime. A 50# bag of pelletized lime, would be a rate of about 300# / acre which would boost your calcium numbers up some. Clovers are like beans, they need calcium, sulfur and potash.

One other important ingredients for clover plots is sulfur. Given your high Magnesium rates, this is a prime opportunity to use gypsum (calcium sulfate) as your sulfur source.

Based on your test, my inputs would be:

- 50# 6-28-28 (or 6-24-24, whichever is available) --> 84 # P / 84# K
- 50# pelletized lime
- 20# gypsum

Bassattackr not sure I’m following what you’re illustrating on the —> 84# p/84# k???

also could you unpack the magnesium rate and how that correlates to a prime opportunity to use gypsum? what is their relationship? Is high magnesium not something I necessarily want or is that a good thing?

lastly, can I find sulfur in some sort of pellet or granular form that I can spread just like fertilizer or is it more of a liquid spray?

 

[Bassattackr]

If using a 50# bag of 6-28-28: The breakdown of that analysis is 6# N / 28# P / 28# K per 100# of material.

28# P & K at 1 / 6 acre is 28 # * 6 (6x rate per acre) = 168# * 1/2 rate (Since you're using 50# instead of 100#) = 84# for the 1/6 acre area. Make sense?

The sulfate form of sulfur in calcium sulfate drops magnesium out of the soil, once your calcium saturation reaches 60%. If you're below that, its still a nice cheap form of sulfate sulfur at less than 6$ a bag. Excessive magnesium is not good, it tightens soil (concrete hardness, poor drainability) and ties up other nutrients.

Sulfur/sulfate is extremely important for root development, protein elevation and taste (palatability). Most underrated nutrient IMO. Any "crop" that develops a higher protein level - soybeans, clover, wheat and even corn need sulfur. Good options for sulfate sulfur are manure, calcium sulfate (gypsum) and some other forms of fertilizer (Such as AMS). Sulfate is just the form of sulfur that plants use.

 

[Rous14]

If using a 50# bag of 6-28-28: The breakdown of that analysis is 6# N / 28# P / 28# K per 100# of material.

28# P & K at 1 / 6 acre is 28 # * 6 (6x rate per acre) = 168# * 1/2 rate (Since you're using 50# instead of 100#) = 84# for the 1/6 acre area. Make sense?

The sulfate form of sulfur in calcium sulfate drops magnesium out of the soil, once your calcium saturation reaches 60%. If you're below that, its still a nice cheap form of sulfate sulfur at less than 6$ a bag. Excessive magnesium is not good, it tightens soil (concrete hardness, poor drainability) and ties up other nutrients.

Sulfur/sulfate is extremely important for root development, protein elevation and taste (palatability). Most underrated nutrient IMO. Any "crop" that develops a higher protein level - soybeans, clover, wheat and even corn need sulfur. Good options for sulfate sulfur are manure, calcium sulfate (gypsum) and some other forms of fertilizer (Such as AMS). Sulfate is just the form of sulfur that plants use.

Ah, I think I’m tracking now….I thought you were saying 84 pounds of P and K when I first read it but you are saying 84 pounds of 6-28-28 of which will equate to an application of around the 21 pounds of each that I need. I think anyway? Haha.

Think i read that the sulfur/sulfate will lower the soil ph….is that true and if so is that a concern? Or is that why id also add the lime at same to essentially counteract and make it a wash.

Also, when it comes to p and k, other than wasted expense does it do any harm to a plot if too much were to get applied as long as we’re not talking crazy excessive?

great information, thanks a bunch for the explanation!

 

[Bassattackr]

Ah, I think I’m tracking now….I thought you were saying 84 pounds of P and K when I first read it but you are saying 84 pounds of 6-28-28 of which will equate to an application of around the 21 pounds of each that I need. I think anyway? Haha.

Think i read that the sulfur/sulfate will lower the soil ph….is that true and if so is that a concern? Or is that why id also add the lime at same to essentially counteract and make it a wash.

Also, when it comes to p and k, other than wasted expense does it do any harm to a plot if too much were to get applied as long as we’re not talking crazy excessive?

great information, thanks a bunch for the explanation!

I am saying with a single 50# bag of 6-28-28, you would be applying 18# of actual N, 84# P, and 84# K to your 1/6 acre area.

Deep dive into soil structure and fertility:

Compared to Calcium, magnesium will elevate pH by 1.65X versus lime. Soils that tend to be higher in magnesium (mine is identical to yours) give a false indication of soil fertility by showing an elevated pH. So, your pH can be adequate (6.2+ for example), but you still could have a calcium deficiency.

Typically, Calcium below 60% base saturation is not ideal. Until you get a better soil test showing actual base saturation percentages (From Midwest Labs, etc), you'll never know for sure.

Pure sulfur/sulfate will lower pH by bonding with magnesium and dropping out of the soil (cation / anion relationship). Since magnesium is 1.65X more effective at elevating pH than lime, you can lose pH with pure sulfur/sulfate. The calcium in calcium sulfate can even out the process however, so typically gypsum doesn't move the soil pH meter much.

Adding high Ca / low Mg lime will right the ship, increase pH and get you to a better soil structure and balance overall. Yes, your pH will be a "wash" but you will have a much better physical soil structure, which lends itself to better microbial growth, moisture management and overall soil fertility.

Think of Calcium and Magnesium as a teeter totter in the soil. Elevating calcium by one percent (base saturation), will drop magnesium by one percent - And vice versa. Calcium makes the soil more porous (good if you have tight soils), and magnesium tightens the soil (good if your calcium is too high and your soil doesn't hold moisture).

Excessive amounts are not the best practice. In short terms - Any excess of one nutrient pushes out another. As the soil colloid (dinner plate) can only hold so much (food), before it is lost by dropping out of the top layer.

 

[Bassattackr]

Nitrogen and its Effects on Soil Fertility:

Much like the Sulfur / Magnesium relationship - Nitrogen and Calcium share a similar bond. Nitrogen bonds with calcium and drops calcium out of the soil (off the soil colloid or "dinner plate"). That is why cropland with routinely added nitrogen (Pure Anhydrous Ammonia is the worst), will acidify and tighten the soil and drop your pH. Remember, dropping Ca only will elevate your Mg simply by their teeter totter relationship.

So if you add Nitrogen, you need to add calcium.. Calcium acts like the "dump truck" hauling up nitrogen into the plant. Can see how the soil amendment cycle is necessary for commercial farming.

Consider AMS (Ammonium Sulfate 21-0-0-24S) as the most acidifying of all fertilizers. The N drops out Ca, and the S drops out Mg. However, AMS is also the most stable form of nitrogen (will release over 60+ days in warm soils) and a great form of sulfate.

Soil structure and fertility are all about balance, much like making room on your plate for everything at thanksgiving dinner - You put too much turkey and mashed potatoes, there's no room left on the soil colloid (dinner plate) for corn and green beans!