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.
Soil pH is a measure of soil acidity or alkalinity and can affect availability of essential soil nutrients to your plants. Your soil is acidic if the pH is lower than 7, a neutral soil has a pH of 7. If your soil has a pH above 7 it is basic or alkaline. Follow the test recommendations concerning adjustment of pH. If your soil is alkaline you can add sulfur to lower the pH. You should add lime if your soil is too acidic. Add lime only as recommended by your soil test results. Organic matter in the soil changes continually. How much organic matter you have in your soil depends on rainfall, temperature, aeration, and many other factors. It takes a lot of compost, manure, peat moss or mulch to make small changes in percentage of organic matter in the soil. Typically good soil contains 2 to 10% organic matter.