A high pH can be lowered by adding which chemical?

A high pH level, often indicating an alkaline soil, can be effectively lowered by adding sulfur. When sulfur is introduced to the soil, it undergoes a microbial oxidation process that converts it into sulfuric acid. This acidification helps to decrease the pH level, making the soil more acidic, which can improve nutrient availability for plants that prefer lower pH environments.

In contrast, lime and calcium carbonate both increase soil pH, making the soil more alkaline. Therefore, choosing those options would further exacerbate the high pH issue rather than remedy it. Aluminum sulfate can also lower pH, but it primarily does so in a manner that can contribute to aluminum toxicity in certain soils. Thus, sulfur is typically the safest and most effective choice for reducing a high pH in agricultural practices.