Yes there is a foot note for critical level at which no additional nutrient is recommended.
I wondered about the calcium too. The limestone that I’ve bought has very little magnesium. I could write back and ask but I’m assuming that the lime is needed for the acidity in disregard for the calcium. ???
Yeah, mine too! I have access to the fertilizer calculators on A&M site and the best mix I could get would be a 10-20-15. I don’t think this is an available mix and the custom fert places won’t mix unless you get 2 tons.
So while I hesitate to jump in with advice for soils and climates which I am not familiar with, just some things to consider or perhaps run by your local experts:
If the lime rec is just to adjust pH, you might consider other ways to do that. There are fertilizers which are alkaline, and could perhaps be substituted for lime (in whole or in part). DAP is one IIRC that is widely available and would fulfill the P needs too. Likely others out there as well.
If they gave you the CEC numbers with the test, those could be a guide as to what sort of things you might want to add anyway that could also raise the pH. I am usually going the other way with pH (trying to lower it), but I have managed to create a bunch of amendments which help lower my pH while building other aspects of the soil. It is a long term plan/goal but seems to be working. I’ve never had your situation, but I would think the same could be done for your soil, if you were so inclined.
Of course its all up to you. But I have found it useful to look at soil health at several time frames. Immediate (or next growing season), medium term and long term.
The numbers on fert bags indicate the percent of each nutrient. Take a 50lb bag of 10-10-10 (N-P-K, or Nitrogen-Phosphorus-Potassium). Each bag will give you 5lb of each nutrient (50 x .10). So a 50lb bag of 10-20-20 will have 5lb of N, and 10lb of P/K.
The rec is abt 1lb of N, and 2lb of P/K per 1000 sqft. She has 48K sqft, let’s round it up to 50K for simplicity sake. One 1000 sqft plot needs 1lb of N and 2lb of P/K, so a 50lb bag of 10-20-20 has by weight 5lb of N, 10lb of P/K. So, one 10-20-20 bag will cover five 1000 sqft plots. She has 10 times that amount of area, approx, hence she’d need ~10 bags of 10-20-20.
OR, another way to figure it-
She needs 1lb of N, 2lb of P/K per 1000 sf. Since she has abt 50,000 sf, she’d need 50lb of N, and 100lb of P/K in total. Hence, ten 50lb bags of 10-20-20.
There might be other formulations that might work, but it’s easier to find 10-20-20. There is also a 5-10-10 mix, but you’d need 20 bags of that for the same purpose. My guess is both formulas cost close to similar price, so get the more concentrated mix at a local ag store.
I noticed they’re also recommending 0.5lb of Sulfur per 1000 sqft. That might throw a wrench in my calculations.
A way to get S incorporated would be to use a formula that uses Ammonium Sulfate (NH4)2-(SO4) as the N component. But since your soil is so acidic, adding Sulfur prob wouldn’t be a good idea. A bag of 10-20-20 probably uses something like Ammonium Nitrate, or some other kind of Nitrate. If you want Am Sulfate, I think the only way to get it is in an X-0-0 formula, that is, nothing but N and no P or K with it.
But, I don’t know how critical S is for fruit trees, so maybe you don’t need to worry about it. Your P levels are actually lower than your S levels, but I’d think getting the P to proper levels is more important. But, others on here could perhaps comment as to S’s importance.
Early in the season the roots function more in the soils top but if conditions get too try the roots begin to function only further down the soil profile. In the east coast traditional apple growing has usually been done without irrigation and it is always recommended that growers take separate tests for top and sub soils.
At many sites I manage turf is maintained under fruit trees with frequent watering so this probably isn’t a concern there. Of course, the fruit is never quite as good as it could be.
I am certainly no expert on lime, but I do know that some pelletized limes are calcitic and some are dolomitic. If you’re looking to raise ph and calcium (and not magnesium) you want to use calcitic lime. If you need to raise magnesium and ph you use dolomitic.
Around here (central MN) it isn’t easy to find calcitic pelletized lime. Menard’s has been my best source for calcitic pell lime.
We are about to open up another approx 1/2 acre so we will put it on that.
I think I’m going to spot fertilize just on the trees. I can’t see feeding the grass between the trees with the fertilizer. And that is going to be probably just a 13-13-13 or something similar.
If I fert my trees, I usually just give them about a cup of triple-10 per spring, sprinkled around the drip line. If the trees have put on a lot of growth, like 2ft in most of the branches, I skip the fertilizer.
