[daganh62]

I tested my soil ph yesterday and its around 7.5 (used an analog tool so i don't have the exact number yet). what is the best way to lower it on a newly sodded lawn.?

 

[Greendoc]

Better get that checked by a lab. Those meters with a dial and a metal probe are not accurate if there is any kind of salt in the soil.

 

[Bunnysarefat]

I would suggest getting a more official test from a lab. Most local university systems seem to offer the best prices but there are simple kits on amazon as well where you send off the sample to their lab and they email you the results.

From what I've read, lowering PH in soil is not easy, and especially not something that can be done quickly.

My soil test came back with a 7.1 reading. I've found in using different types of fertilizers that I get the best response from fertilizers that have high sulfur contents, which will lower PH in the short term, not sure how effective it is long term in actually dropping it.

 

[Greendoc]

It will drop it. If you are using Ammonium Sulfate rather than Urea as your N source, that will influence pH as well as be a much more efficient N source. It is not actually the Sulfate that is causing the pH drop. Ammonium Sulfate is (NH4)2-SO4. When that is converted to NH3, what is left is H2SO4. Sulfuric Acid. On soils with a pH over 7, applying anything with Urea is not efficient because the Urea reacts with the alkaline soil and is lost as Ammonia and N2 gas.

 

[Ridgerunner]

High soil pH is commonly due to lime content in the soil. In most cases, the amount of lime present in soil is so great, that removing enough of it to make any significant reduction in pH becomes an effort in futility. Some soil testing laboratories offer a test that will determine the amount of carbonate (lime) in a soil. (do not confuse a lime product quality test for a soil carbonate content test)
Lowering pH
Elemental sulfur is the most effective product for neutralizing lime.
1 atom of sulfur (S) will produce (through biological processes) 2 atoms of hydrogen. 2 atoms of hydrogen will neutralize 1 molecule of CaCO3.
Consequently, 1 lb of sulfur can be used to neutralize 3.12 lbs of calcium carbonate.

Other acidifying sources:
Indexed common fertilizer acidifying effects (the amount of CaCO3 that one pound of product will neutralize):

Sulfur coated Urea (38-0-0): 1.18
Ammonium Sulfate (21-0-0): 1.10
Urea (46-0-0): 0.81
Ammonium Nitrate (34-0-0): 0.60

Higher numbers indicate greater acidifying effect. For example 1# of Ammonium Sulfate (21-0-0) will neutralize 1.10 pounds of 100 CCE limestone and 5# of 21-0-0 (equal to an application of 1.05 lbs/k of N) would neutralize 5.5 lbs of 100 CCE of limestone.

 

[viva_oldtrafford]

Pour the 21-0-0 to it. 1#n/k is a great start.

For the soils guys. If I aerify then topdress with an OM/sand mix, elevating the C:N ratio higher than 30:1 (fixing nitrogren), would I still get the benefit of reducing pH, or does the C anihilate any and all forms of N?

 

[Ridgerunner]

Those are interesting questions. I'm not a "soil guy," just a layman with an interest (albeit somewhat OCD at times). I'm assuming by the phrasing, that you're indication a rise in the soil C:N ratio to 30:1. Regarding the benefit of pH reduction, off-hand, I'd think if it was a fresh organic material like sawdust, there wouldn't be much reduction in the amount of hydrogen that would become available from the "acidifying" amendment. If the addition was an humic substance like peat moss, I'd guess there might be some loss in benefit due to the possible chelation of some ammonium, protecting it from nitrafication and hydrogen production. On "anihilat[ing] any and all forms of N," the literature consensus is that the decomposition of organic material places an increased demand on soil N content. On either point, I'm unsure how you would quantify the effect. When it comes to soil I've found that, seldom, if ever, does the phrase "any and all" apply. That's about the extent of my knowledge and supposition and out-right guessing.

 

[Ridgerunner]

@viva_oldtrafford I'm thinking that there must have been more to this. I realize that as a golf course super, you aren't likely to be actively attempting to lower pH or increase OM, but what has been your experience with high C:N OM and it's effect on any expected change in pH and nitrogen availability from a subsequent N fertilization?

 

[HoosierLawnGnome]

I tested my soil ph yesterday and its around 7.5 (used an analog tool so i don't have the exact number yet). what is the best way to lower it on a newly sodded lawn.?

Don't necessarily be worried about soil pH. In and of itself it's like a measure of a few things in the soil, but there is much more going on - and pH isn't necessarily the ultimate goal. having the right pH absolutely does not guarantee you will meet your goals.

Yes, there are several ways to lower soil pH. BUT, depending on what your goals are, where your soil is at overall (which can be determined by having a professional lab analyze it), and what you need to do to achieve your goals given your soil's state (having someone knowledgeable that looks at your goals and that test to make recommendations) - you won't know if you should even care about pH.

So, see how the question "best way to lower soil ph"? is highly subjective? The best method is highly subjective depending on your goals and soil, but the question itself assumes focusing on pH is the best thing for your situation.

There's no way to know with the information at hand.

 

[viva_oldtrafford]

@viva_oldtrafford I'm thinking that there must have been more to this. I realize that as a golf course super, you aren't likely to be actively attempting to lower pH or increase OM, but what has been your experience with high C:N OM and it's effect on any expected change in pH and nitrogen availability from a subsequent N fertilization?

I'm fortunate in that lowering pH is not an issue I deal with. Acidic soils is another issue across a few different holes and one I'm in the process of fixing.

The question was nothing more than curiosity. 21-0-0 is often used as a remdedy for akaline soils - i use 21-0-0 but for different reasons (grow ins, post aerification), and it got me thinking about nitrogren fixiation and how that can affect pH reductions. We aerified our range tee a few years ago and came back to fill with a sand + om mix (high clay content mix, totally different then how we would do greens). Anyhow, after the topdressing was down, we put 21-0-0 @ 1#n/k....and nothing happened. Then a week later we went and put 2#n/k...and nothing happened. We were scratching our heads at this point. Then it about 10 days later we came in to see celebration approaching 1"! After some digging into our notes, we came across nitrogen fixation and how too much C (topdressing with flecks of wood) will consume N, redndering it useless until C levels decline.

I have 2 fairways that I'm trying to raise both CEC and pH (2.7 and 5.0). Soils tests show an increase since our 2,400lb/a application (we were at 4.7), but I'm just now trying out humic acid in the same fairways. I'll test again in June/July and have a better picture.

 

[Ridgerunner]

Your high C:N experience is a case on point on how N immobilization can at least temporarily impact plant N availability for those of us applying saw dust to our lawns and gardens.

I have 2 fairways that I'm trying to raise both CEC and pH (2.7 and 5.0). Soils tests show an increase since our 2,400lb/a application (we were at 4.7), but I'm just now trying out humic acid in the same fairways. I'll test again in June/July and have a better picture.

Is 2.7 the CEC and 5.0 the pH?
What material was applied?
If you wouldn't mind, please post again on this after you do the June/July tests post the HA apps.