Soil Science: A Comprehensive Overview PDF

**SOIL** - It consists of matter in three states - solid, liquid, and gas → The solid component consists of a mixture of mineral grains plus material of biologic origin. → It is a product of weathering processes and a medium capable of supporting plant growth → The water in the soil wets the mine...

**SOIL** - It consists of matter in three states - solid, liquid, and gas → The solid component consists of a mixture of mineral grains plus material of biologic origin. → It is a product of weathering processes and a medium capable of supporting plant growth → The water in the soil wets the mineral grains. The soil moisture tends to contain high levels of dissolved substances. Both the nutrients and moisture in the soil allow plants to grow → ***Carbon dioxide, methane,*** and ***oxygen*** fill the open spaces in the soil → **semi non-renewable** resource since it takes a long time for water and nutrients to accumulate inside it. **SOIL TEXTURE** - refers to the proportion of particles that fall into each of the three size ranges, namely clay, silt, and sand **HUMUS** - partially decayed organic matter in soil, critical to soil fertility **SOIL TEXTURE TRIANGLE** - It is a diagram which helps identify the type of soil based on its composition +-----------------------------------------------------------------------+ | **4 MAIN CHARACTERISTICS OF SOIL:** | | | | **SOIL DEPTH** - Thickness of a soil from the surface to a | | root-limiting layer such as bedrock or seasonal water table | | | | **SOIL TEXTURE** - The relative amount of sand, silt, and clay in | | each soil. Affects more specific characteristics like porosity, | | drainage, and permeability | | | | **SOIL STRUCTURE** - The shape and size of soil aggregates. | | Influences the size distribution of pores in the soil | | | | **\ | | ORGANIC MATTER** - Amount of organic matter within a soil. Affects | | more specific characteristics and is affected by soil management | +-----------------------------------------------------------------------+ **SOIL PROFILE** - The sequence of soil horizons from the surface down to the underlying bedrock **\ SOIL HORIZON** - One of the succession of zones or layers within a soil profile, each with distinct physical, chemical, and biological characteristics  +-----------------------------------------------------------------------+ | **O HORIZON** - contains the accumulation of organic matter | | | | **A HORIZON** - typically dark in color because of the humus present | | | | **E HORIZON** - a pale layer that is sometimes present in forest | | areas | | | | **\ | | B HORIZON** - brownish or reddish because of the presence of iron | | hydroxides that has leached from the surface. Also called the \"zone | | of accumulation." | | | | **C HORIZON** - made up of parent material underneath (bedrock) in | | various stages of weathering | | | | **BEDROCK** - solid unweathered rock | +-----------------------------------------------------------------------+ **SOIL QUALITY** - the capacily of a soil to function within ecosystem and land-use boundaries to sustain biological productivity, maintain environmental quality, and promote plant and animal health. → Human activities such as farming, urbanization, and waste disposal can greatly affect the soil quality +-----------------------------------------------------------------------+ | **EFFECTS OF POOR SOIL MANAGEMENT:** | | | | → **SOIL POLLUTION** | | | | **→ EROSION** - occurs when soil particles are detached, transported, | | and deposited. Although this may occur naturally, removal of plants | | and trees from the soil may lead to accelerated erosion | | | | → **DESERTIFICATION** - the extreme degradation of productive land in | | arid and semi-arid areas. This can create poor quality vegetation | | | | → **ACIDIFICATION** - occurs acidic cations (Hydrogen, Aluminum, iron | | and manganese) are concentrated in the soil. The pH decreases and | | soil becomes more acidic. | | | | - This is a natural process in weathering. However, the use of | | certain fertilizers to provide food, like anhydrous ammonia, | | causes soil to become more acidic much faster. | | | | → **SALINIZATION** - is the build up of salt on the soil surface. | | This affects the physical soil quality and hinders the growth of | | plants | | | | → **DEFORESTATION** | | | | → **HEAVY METAL CONTAMINATION** - has a toxic effect on soil | | microorganisms and plants. Even at low concentration, it hinders some | | physiological metabolism of plants. | | | | - Heavy metals may further contaminate the water table. | | Accumulation in plants may also pose a danger to animal and human | | health. | | | | → **EUTROPHICATION** - occurs when excessive amounts of nitrogen and | | phosphorous, because of synthetic fertilizers, accumulates in land | | and aquatic systems. This is a form of nutrient pollution. | | | | - This is the cause of algae blooms in aquatic environments which | | depletes the oxygen in water. | +-----------------------------------------------------------------------+