All I can think of is:
Lots of organic material in the soil
Micro nutrients/base cations to help with buffering acidity
Pre-mix pH up solution in your fertilizer solution (NOT practical to me)
I don't worry about it, at all.
Many fertilizers are acidic, but they don't seem to result in any significant pH change. The rain is strongly acidic as well and this hasn't eliminated alkaline soils.
The earth has a lot of buffering capacity in most cases and a little fish emulsion isn't going to have much impact on that. Even lime and sulfur are only able to shift pH for a limited time. Stop applying it for a few years and pH drifts back to where it was previously.
In most cases the pH of highly organic soils isn't very relevant to plant health or nutrient availability. It's the strongly mineral soils lacking a significant organic portion where pH is more of an issue. Those with more of a chemistry background can explain the whys.
No matter what organic matter you have, pH does matter. Just because you have a lot of organic matter doesn't mean you can let pH run to 9,10,11,12 and be ok... Maybe I didn't understand you correctly?
I would not say a pH of 12 is OK. However the fish emulsion is not something that is going to overwhelm the buffering capacity of soils.
The principle is the same with the acidic rain. The soils do not experience a pH shift of any significance.
A trick used by growers of acid loving plants like blueberries is to add sulfuric acid to the irrigation water and home growers often use vinegar. Both are acidic, but neither actually changes the soil pH perceptibly, they simply result in flushing acidic water (temporarily) over the root zone. The buffers in the soil then neutralize the acid and that's the end of it.
The point about organic matter making pH less relevant is that nutrients aren't tied up in organic matter due to pH to the same degree they are in mineral soils. I wouldn't carry that to the extreme of a pH of 12, but there is a much larger pH range in which plant needs are met in organic soils versus mineral only ones.
Again, someone better versed in chemistry will have to explain the technicalities.
One last point, many gardeners amend soil with peat moss and it's very acidic stuff, often in the 4.0-4.5 range. Because it is organic rather than mineral it doesn't result in the poor plant performance one might think such an acidic material would. The issue of pH is more relevant to soils lacking in organic matter than they are to organic gardeners as well as container gardeners whose growing media is largely organic matter such as peat or bark.
You asked the same question last year. It's not a problem.
So- how do you deal with it? Don't think about it.
Here is a link that might be useful: pH of fish emulsion
"One last point, many gardeners amend soil with peat moss and it's very acidic stuff, often in the 4.0-4.5 range. Because it is organic rather than mineral it doesn't result in the poor plant performance one might think such an acidic material would. The issue of pH is more relevant to soils lacking in organic matter than they are to organic gardeners as well as container gardeners whose growing media is largely organic matter such as peat or bark."
That's news to me, I'll ask my soil sci professor for details, I'm interested to know why that would be.
Hi hoorayfororganic...do you enjoy gardening...:-) Franklin
OK, the fish emulsion is acidic. If you put one tablespoon in a gallon of water with a 6.8 pH you won't have an acidic solution. Then you distribute it on 100 sq ft of garden with a soil pH of 6 to 7. The acidity of that small amount of fish emulsion is not a factor. It's a matter of dilution. Tom
You have people that use it all the time and it's never an issue. Believe it.
It's not all really as complicated as purists would have you believe.
Hi hoorayfororganic...I use ...and have used for many years...the liquid fish/seaweed combo from Neptune's Harvest. I buy it by the five gallon pail...with a free tee shirt thrown in...and free shipping...:-) I have never seen any bad effects to the soil or to my plants...trees...bushes from the use of this product. I apply this product using a hose proportioner as I water with a sprinkler. When I lived close to the sea shore I hauled many yards of seaweed for my gardens and compost piles...and never saw any bad effects from using it at all. I'm still close enough to haul now but my back won't allow me to do so...and I got tired of picking all the junk out of it...such as plastic knives and forks and spoons...and a host of other collectables...:-)
As pablo nh has said...the purists complicate things beyond what the average gardener needs. Gardening can be...and is...a very rewarding hobby to have. It is a forgiving hobby as far as methods are concerned. You can be less then perfect with your methods and still end up with satisfactory gardens and yards.
And then there are the BS artists...and practictioners of voodoo and witch craft on here and other garden forums...that give one a good laugh thats good for the gardeners soul and spirit...:-) Two good examples are home compost piles heating up to the point of catching on fire...and dew ponds that fill up by themselves. The dew pond thing is really a classic...and might still be in the achives if you look. Anyway keep things simple and enjoy your efforts in gardening...Franklin