According to the University of Massachusetts, the physical texture of soil has an effect on its chemical characteristics. Clay soil is made of very fine rock particles that compact together very tightly. It also has a high exchange rate of cations, which are positively charged ions. Plants absorb most soil nutrients as cations. Does this Spark an idea?
Oxygen
Oxygen is classified as an anion, which is a negatively charged ion. Oxygen in clay soil tends to be low compared to sandy or loamy soil. This is because the spaces between the particles of clay soil are packed very tightly together. Additionally, clay soil particles repel the negatively charged oxygen anions because the clay is filled with tiny negatively charged particles called colloids.
Silicates
Clay particles are primarily made up of tiny particles of weathered rock. For this reason, the largest concentrations of clay soil are in floodplains near large mountain ranges such as the piedmont area that lies between the Appalachian mountain range and the coastal soil of the Atlantic region. These tiny weathered rock minerals are called silicates. Examples of silicate particles include montmorillonite, vermiculite, micaceous and kaolinite.
Oxides
Chemically speaking, clay soils differ from the large rocks from which they are formed because the weathering process removes water-soluble components such as calcium. Because of this, soils contain more insoluble elements such as aluminum and iron oxides. The high concentration of iron oxide in clay soil is what gives many clay soils a red coloring.
pH
The pH of soil is a measure of the balance between soil acidity and alkalinity. The measure of pH balance is a 14 point scale. 7.0 is an indicator that soil is pH-neutral, or balanced. Plants that are planted in soil have a specific pH range at which they can absorb nutrients that are present in the soil. Most plants prefer to grow in a neutral or slightly acidic range. A few plants, such as blueberries or azaleas, grow well in a lower range. Clay soils may be acidic or alkaline in nature based on the makeup of the rocks from which their particles were formed. For example, piedmont clays, which have high levels of iron oxides, are acid in nature with a low pH. Houston black, a dark brown or black clay soil, is lower in oxides and has a slightly alkaline pH rating.
Tags: clay soil, negatively charged, from which, iron oxides, measure balance
