Introduction to Soil

The major components of soil are mineral matter (sand, silt, and clay), organic matter, water, and air. Soil consists of minerals, air, water, and living matter that accumulate in layers and become compacted over time. Dirt is the displaced soil that can’t be easily associated to where it originated.

Soil formation is affected by 5 factors: climate, organisms, topography, parent material, and time. First, parent material is broken down through weathering. Then, biological activities allows for accumulation of organic matter. This process is very slow.

One major factor when examining soil is clay, silt, and sand distributed evenly (loam). Another factor is the size of particles which affects liquid and air flowing through the soil (porosity). Soil color provides important information on many of the chemical characteristics of soil and on the drainage class and general behaviors of water in soil. It may also help soil scientists in classifying the soil. Generally the darker, more moist soils are the more nutritious soils compared to lighter, drier soils because the darker colors usually indicate more humus. Structure can tell you if the soil is strong or weak. If it is strong than it can stay together under stress and allows for better water movement through the soil. If it is weak it will fall apart under stress. Soil pH influences the solubility of nutrients. It also affects the activity of micro-organisms responsible for breaking down organic matter in the soil.

(http://www.oneplan.org/Water/soil-triangle.asp)

This is a soil texture triangle that shows the percentages of the 3 components in different kinds of soils.

Illinois soil is usually dark brown or black. Silt loam (0-50% sand, 0-28% clay, 50-80% silt) and silty clay loam (0-20% sand, 40-70% silt, 28-40% clay) textures are very common in Illinois. This has a fine texture and forms ribbons that breaks into pieces. The pH of Illinois soil is mainly 6.0-6.5 which is slightly acidic.Hawaii soil is usually reddish and has mainly silty clay soil (40-60% silt, 0-20% sand, 40-60%). Georgia soil is also usually red and has clay soil (40-100% clay, 0-40% silt, 0-45% sand). Arizona also has red soil and has a lot of clay (40-100% clay, 0-40% silt, 0-45% sand). Illinois, Hawaii, and Georgia have acid soil while Arizona has more alkaline soil.

(http://www.allposters.com/-sp/Tree-Roots-in-Laterite-Soil-Formed-from-Tropical-Weathering-of-Basaltic-Lava-Flows-Kauai-Hawaii-Posters_i9004690_.htm)
Hawaii Soil

(http://www.uvm.edu/cosmolab/?Page=projects/soil/soil.html)
Georgia Soil

(http://www.ehow.com/about_6577550_type-soil-arizona-have_.html)
Arizona Soil

(http://www.illinoissoils.org)
Illinois Soil

One economic reasons why farmers should be interested in soil analysis is because if a farmer is able to have/create healthy soil with equal amounts of sand, silt, and clay then the farmer will be able to grow more larger, better tasting crops. Another economic reason is that the farmer won’t have to waste money on extra fertilizers and farming products if he/she knows exactly what he soil needs. One social reasons for a farmer to be interested in soil analysis is that if the farmer knows about his/her soil than they can help prevent run-off and thus reduce pollution because the farmer will know what nutrients need to be added and won’t add extra. Another social reason is that the farmer will be able to have healthy soil and know how to take care of the soil which will allow the farmer to not ruin his/her land that he/she can’t use it.