Will that be enough to take care of the (huge) manganese deficiency? Is it organic/safe to use around the fruit trees?

Most plants grow best when the soil pH is in the 6.0 to 7.0 range since that is where most nutrients are most readily available, so your soils pH is fine.

Optimal amount of organic matter is in the 6 to 8 percent range, so at 2.24 percent what is in that soil is low. Add more organic material, compost and any other vegetative waste you can.

Optimal levels of the major plant nutrients are: Phosphorus 50 to 170 pounds per acre, Potash 400 to 800 pounds per acre, Calcium 3,000 to 8,000 pounds per acre, and Magnesium 600 to 1,600 pounds per acre.

Very possibly simply getting the amount of organic matter in the soil up to optimal levels may be all you need do, as many of us have found over time.

kimmq is kimmsr

I like kimmq's plan. Both greenwaste and manure composts tend to provide a pretty good shot of potassium and you'll probably get some manganese and magnesium out of it too.

In regards to zinc, it's no big deal. High zinc can inhibit the uptake of other nutrients and create some deficiency issues. However, you typically won't see that happen until it's well into the hundreds of parts per million (via Mehlich 3). Also, even if it is a little high, it typically won't be an issue if the pH of your soil is above 5.5 or so. Even if it's there at a relatively high level, it won't be soluble enough to be a problem in a pH much higher than that.

OK, thank you. That takes a while before it breaks down into usable OM, though, right?

Some of them have been showing signs of manganese deficiency (I don't understand why they aren't all looking incredibly deficient), is there anything I can do in the shorter term? I applied the Southern Ag Citrus nutritional spray at the amount for deficiencies (2 tbsp/gallon) as a drench last Sunday (before the soil test, it got lost in the mail), but I don't know if that's enough.

This is what one of the worse leaves looks like:

On the other hand, though, here's fresh growth on a mulberry 20 feet away that looks great:

If the results are accurate, wouldn't every tree be affected equally badly and be doing much worse than they are? Could they be off? Not wrong, I'm sure there's a deficiency, but is it that bad?

different plants have different requirements so it's not unusual to see different levels of performance from one plant type to the other under the same conditions.

Also remember that soil chemistry can vary from spot to spot depending on what has been applied there in the past, what has been grown there, how much it has been watered,etc. There is also just natural variability in the soil. A soil test can give you a general idea of the average chemistry if you do a composite (grabbing soil from a bunch of spots and combining it into one sample) but you still have some variability.

Another thing to consider is that anything that has a negative impact on root function can inhibit nutrient uptake and can contribute to the appearance of deficiency symptoms. Things like root disease, soil compaction, root pruning, etc. Over watering and under watering can also negatively affect nutrient uptake.

If you add some compost, ensure that the soil isn't compacted and their are no disease or pest issues and soil moisture is sufficient without being excessive, and the trees don't respond in a reasonable amount of time, then maybe thinking about adding manganese specifically.

The sample was a composite from four evenly spaced areas across the yard mixed together in a bucket.

So, basically, the conclusion here is that I should put compost around each tree and see how things go before trying to fix any specific deficiencies. I can get composted horse manure nearby. About how much will it take to put a deep ring around 24 trees (12 large and 12 small)?

Age of the sampled leaf also determines its appearance.