how to make soil acidic for Avocado trees?

Question

What chemicals or amendments can be used to make soil acidic for avocado trees?

Answer 1

Although avocado trees tolerate both acidic and alkaline soils, the best pH range for a successful tree ranges between 6 and 6.5; this slightly acidic range can be achieved by amending the soil periodically with sulfur.

https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/raise-acid-level-soil.htm