Last year our summer was baking hot: 100+ degrees for months and no rain. It was hard on my trees, especially my pear tree. My pear gets iron chlorosis (many fruit trees do) and also I had calcium deficiency in the fruit, causing corkey spots. For both of these to develop you need high ph soil, drought and inconsistent watering practices (I’ll meekly raise my hand here. I was not as consistent at watering as my plants needed me to be, but I was very ill. And: yes, just like tomatoes get blossom end rot from poor watering practices, so can a fruit tree.)
Usually, if you have clay soil, the only deficiency is nitrogen. But in high pH soil certain trees can develop problems taking up iron. Since the issue is rarely that there’s not enough iron, the real problem is the pH of the soil. The iron is there but your tree can’t use it.
There are also problems with free lime. If you have free lime you can put a bag of Sulphur out there and it’ll fizz like an Alka seltzer and react to the lime and calcium and be gone. There are some soils that are so full of Ph altering lime that you can’t realistically change the soils pH. It’s just too much a part of where you are to ever hope to overcome it. Here’s a good article on that: https://ask.extension.org/questions/135890
I happen to have Super high pH soil and I knew that Sulphur and iron soil treatments were going to be a big waste of money. So. I did some research and found some implants. You drill holes into the tree and then tap in the iron supplement implants, seating them below the cambium layer.
I am impressed already. You are supposed to do this over the dormant season, which I did. As soon as spring rolled around I had 0% iron chlorosis in the tree. 0! This tree has never done this and I am tickled pink! The wounds are beginning to swell and cover the implants and I’m pretty sure, even if we get another dry season, this tree is going to be healthy. Can’t say enough about these things! If you’re interested, you can get them here: Tree Implants