Not sure of where to start, but here goes; A large number of acers in an adult complex with very anemic leaves. Checking numerous areas in the plant beds and lawns shows pH at 6.5 -7.3, however samples taken at 6+ inches depth and sent out for analysis shows pH at 8+. Is this possible? How do I begin to correct the pH from the surface when the surface is acidic and the subsoil is alkaline? Maybe someone can deduce more from the attached pictures? Alkalinity would explain the apparent chlorosis of the leaves, but I'm not sure that that is all that is going on.
Increased pH with depth is quite common, specially with undisturbed soil where the top layer has seen a lot of organic matter which, when decomposing, tend to slowly acidify the soil. Lowering the pH of soils is quite a task and you may Google 'acidifying soil' to learn the many different ways (too long to recall here) to do that. I agree with you that, in addition to high pH, there maybe other problems like mineral imbalance which only a soil test may confirm. Gomero
This complex is about 8 years old, so soil has been disturbed in a somewhat recent past, or would 8 years be sufficient to be subject to what you suggest? I was thinking opposite of your post, that perhaps the fill brought in might be the problem? This problem has been ongoing with some tress having been replaced already.
A little more background information may be needed. What was the problem with the fill dirt or has that issue been determined? How much water is this tree getting, how much is applied in each watering and how often? What is the principal soil type of the native soil and what was the soil type of the fill dirt. Just for the heck of it what was the pH of the fill dirt? What is the pH of the water and are there any nutrient issues with the water such as excess boron, manganese, calcium in the water? The lack of chlorophyll in the leaves does indicate a severe nutrient imbalance, perhaps a toxicity of sorts or the effects of nematodes on the roots. When has this tree been fertilized and what was the composition, the formulation and the applied rate of the fertilizer? How well was it watered into and down through the root zone? A pH of 8 is not alkaline, you are in the saline range. The misses clay loam soil has a pH of 8.2 at 1 to 2 feet down, used to be 9.3 before I took over the yard and landscape tasks. I believe some of our trees in a landscape are still posted in this forum and no where will you see salt burn on the leaves. The top of the tree does not look good to me at all. Much more worrisome than the green depleted leaves with the net veination as seen in the second photo. If you want us to better pinpoint what your issue or issues are you will have to fill in more the blanks (unknowns) for us. As of now you either have severe case of a combination of a nutrient imbalance, chemical or nutrient toxicity, the beginnings of a possible invertebrate problem or lack of deep watering and the issues seen and presented can be the results of all of the above. Jim
In addition, the maple in picture 3 looks like it was topped or "rounded over" during this past summer - numerous stubby branches ending in a neat outline. That may possibly have led to sunburn within the formerly shaded parts of the canopy, which may or may not be a contributing factor to the poor health of these trees. P.S. Topping is probably the wrong word for the type of pruning shown as major branches were not cut, but it certainly looks as if it was given a good haircut.
