Components and Properties of AG 102

Agronomist refer to the origin as Parent Material PM is referred to as a geological formation (a layer of material varying from a few feet to many feet of thickness.) Productive soils develop from PM which equals essential elements for plant life. PM from which productive soils are formed may be classified as residual, transported, or cumulose.

Mineral Particles Air Water Organic materials

O-Organic Layer A-Top Soil E-Eluvial Layer B-Sub Soil C-Parent Material R-Bedrock

Organic Layer O horizon -(living sources) Dead leaves and plants, animal waste, insects, microbes and other organic matter.

Top Soil A horizon -(uppermost layer) Mixture of sand, silt, and clay plus of bit of humus (organic matter). Dark, rich brown in color Plants receive most of their nutrients from this layer

Sub Soil B horizon - (lower level) A mixture of sand, silt, and clay Lower level of organic material and nutrients, few soil organisms

Parent Material C horizon A mixture of rock particles that have separated from the underlying bedrock Contains gravel, stores and releases water

Bedrock R horizon Solid rock where the soil’s minerals come from

Classification of Parent Material Residual Materials (rock materials) Sedimentary, Igneous, Metamorphic Transported Materials Water, Wind, Ice Cumulose Materials ( something accumulated) Peat and Muck (plant materials) Peat: plants that are recognizable Muck: decayed beyond recognition

Color Structure Texture Consistence Fertility Productivity

Color- identification of soil profile Structure-arrangement of soil particles into various sizes and shape Texture-sizes of individual soil particles Consistence-cohesiveness of soil Fertility-provides nutrients for plant growth Productivity-capability of soil to produce a specified plant/output.

Soil Texture What is Soil Texture? It is the proportion of three sizes of soil particles. Which are:  Sand (Large)  Silt (Medium)  Clay (Small)

Sand it is the larges soil separate and is composed mainly of weathered grains of quartz. Sand is also gritty to the touch. Sand grains will not stick to each other. Soil Texture

Sand What will sand do to the soil? It will improve the soil by improving the water infiltration and aeration Soil Texture

Silt is the medium sized soil separated. Silt particles are silky or powdery to the touch Silt grains will not stick to one another just like sand grains. Silt is the best soil as it has the ability to hold large amounts of water in a form plants can use. Soil Texture

Clay is the smallest size soil separate. It is composed of tiny crystals Clay is formed by chemical reactions between weathered minerals to form tiny particle of new minerals. Clay will hold more plant nutrients than any other separate. Clay grains will stick to one another. Soil Texture

There are 12 textural classes which can be seen in the next slide. Soil Texture