Figure 1. Aluminum toxicity does not directly show up on the leaves, but in the root system. Damage to the root system by Al toxicity resembles injury symptoms caused by nematodes. Few lateral roots form and those roots that are present have abnormally thickened tips. Plants become highly susceptible to moisture stress. On acid soils, land-forming operations or erosion can expose acid subsoils. Aluminum toxicity might be found with soil pH less than 5.2 and can be alleviated by liming, which increases soil pH and adds calcium.
Credit: D. L. Anderson