In its pure form, chromium is a steel-gray, lustrous hard metal that has a high polish. It has many compounds that are all colored. [See Periodic Table of the Elements] Of the compounds, the most important are the chromates of sodium and potassium; the dichromates; and potassium and ammonium chrome alums.
Raising pH The ideal pH range for soil is from 6.0 to 6.5 because most plant nutrients are in their most available state. Ifa soil test indicates a pH below 6.5, the usual recommendation is for the application of ground limestone. Inaddition to having the ability to raise pH, limestone contains calcium. Lowering pH Some soils are alkaline and have a pH above 6.5. Some fertilizers (ammonium sulfate, urea, and ammoniumnitrate) create an acid reaction in the soil, so they aid in lowering or maintaining a specific pH.
If blood pH drops below 7.0 or goes higher than 7.8 the body can no longer function and dies. There are many other everyday implications to pH values. Acidic soils must often be treated with lime, which is an alkaline substance,to neutralize the pH before planting. The pH will determine what type of plant will grow and thrive in the soil.