Basic Soil

1 Soil Profile

2 Soil Horizons

3 Soil Series

4 Texture

5 Soil Color

6 Soil morphology

7 Soil moisture

8 Soil PH

9 Soil pore Space

10 Soil drainage

11 Soil Consistence

12 Soil Structure

13 Bulk Density

14 Eluvium

15 Alluvium

1.Soil Profile

Soil Profile refers to the layers of soil; horizon A, B, and C. If you're wondering what horizon A is, here's your answer: horizon A refers to the upper layer of soil, nearest the surface. It is commonly known as topsoil. In the woods or other areas that have not been plowed or tilled, this layer would probably include organic litter, such as fallen leaves and twigs . The litter helps prevent erosion, holds moisture, and decays to form a very rich soil known as humus. Horizon A provides plants with nutrients they need for a great life.The layer below horizon A, of course, has to be horizon B. Litter is not present in horizon B and therefore there is much less humus. Horizon B does contain some elements from horizon A because of the process of leaching. Leaching resembles what happens in a coffee pot as the water drips through the coffee grounds. Leaching may also bring some minerals from horizon B down to horizon C.

2.Soil Horizon

A soil horizon is a layer parallel to the soil   surface, whose physical characteristics differ from the layers above and beneath. Each soil type has at least one, usually three or four are horizons. Horizons defined in most cases by obvious physical features, chiefly color and texture. These may be described both in absolute terms (particle size distribution for texture, for instance) and in terms relative to the surrounding material, i.e. ‘Coarser’ or ‘sandier’ than the horizons above and below. Horizon formation (horizonation) is a function of a range of geological, chemical, and biological processes and occurs over long time periods. Soils vary in the degree to which horizons 

are expressed. Relatively new deposits of soil parent material, such as alluvium, sand dunes, or volcanic ash, may have no horizon formation, or only the distinct layers of deposition. The following horizons are listed with their position from top to bottom within the soil profile. The horizon not listed is the O horizon which is grass and animal/plant life. Soil has three main horizons (A, B, and C), which will be explained below along with other layers.

A horizon

The A horizon is the top layer of the soil horizons or 'topsoil'. This layer has a layer of dark decomposed organic materials, which is called "humus". The technical definition of an A horizon may vary, but it is most commonly described in terms relative to deeper layers. "A" Horizons may be darker in color than deeper layers and contain more organic material, or they may be lighter but contain less clay or obsequiousness. The A horizon is a surface horizon, and as such is also known as the zone in which most biological activity occurs. Soil organisms such as earthworms, pot worms (enchytraeids), arthropods, nematodes, fungi, and many species of bacteria and Achaea are concentrated here, often in close association with plant roots.

E horizon

“E”, being short for eluviated, is most commonly used to label a horizon that has been significantly leached of its mineral and/or organic content, leaving a pale layer largely composed of silicates. These are present only in older, well-developed soils, and generally occur between the A and B horizons. In regions where this designation is not employed, leached layers are classified firstly as an A or B according to other characteristics, and then appended with the designation “e” (see the section below on horizon suffixes). In soils that contain gravels, due to animal bioturbation, a stonelayer commonly forms near or at the base of the E horizon. The above layers may be referred to collectively as the "solum". The layers below have no collective name but are distinct in that they are noticeably less affected by surface soil-forming processes.

B horizon

The B horizon is commonly referred to as "subsoil", and consists of mineral layers which may contain concentrations of clay or minerals such as iron or aluminum oxides or organic material moved there by leaching. Accordingly, this layer is also known as the "illuviated" horizon or the "zone of accumulation". In addition it is defined by having a distinctly different structure or consistency to the A horizon above and the horizons below. They may also have stronger colors (is higher Chroma) than the A horizon.

C horizon

The C horizon is simply named so because it comes after A and B within the soil profile. This layer is little affected by soil forming processes (weathering), and the lack of pedological development is one of the defining attributes. The C Horizon may contain lumps or more likely large shelves of unweathered rock, rather than being made up solely of small fragments as in the solum. "Ghost" rock structure may be present within these horizons. The C horizon also contains parent material.

3 .Soil Series

Soil series is a category in the system of soil taxonomy in the same way that order, great group, subgroup, and family are categories. A soil series is a conceptual class that has, or should have, defined limits in the same way as a great group. The link between the conceptual entity, soil series, and real bodies of soil is the pedon. Any pedon may be classified as a unique soil series, but series have been named for only a very small proportion of the kinds of pedons that occur.

4. Soil Texture

Soil texture is a qualitative classification tool used in both the field and laboratory to determine the classes for agricultural soils based on their physical texture. The classes are distinguished in the field by the 'textural feel' which can be further clarified by separating the relative proportions of sand, silt and clay using grading sieves.

 5. Soil Color

Soil color does not affect the behavior and 

use of soil, however it can indicate the composition of the soil and give clues to the conditions that the soil is subjected to. Soil can exhibit a wide range of color; gray, black, white, reds, browns, yellows and under the right conditions green. Varying horizontal bands of color in the soil often identify a specific soil horizon. The development and 

distribution of color in soil results from chemical and biological weathering, especially redox reactions. Soil color is influenced by the content of organic matter and water as well as the presence and oxidation state of iron and magnesium. Yellow or red soil indicates the presence of iron oxides). Dark brown or black color in soil indicates that the soil has a high organic matter content. Wet soil will appear darker than dry soil. However the presence of water also affects soil color by affecting the oxidation rate. Soil that has a high water content will have less air in the soil, specifically less oxygen. In well drained (and therefore oxygen rich soils) red and brown colors caused by oxidation are more common, as opposed to in wet (low oxygen) soils where the soil usually appears gray.

 6. Soil morphology

Soil morphology deals with the form and arrangement of soil features. Micromorphology is using micromorphological techniques (e.g. Thin sections) and measurements in the laboratory. Field morphology is the study of soil morphological features in the field by thorough observation, description and interpretation. Observations may be refined with the aid of a hand lens. Simple tests are also used in the field to record salient chemical properties (e.g., pH, presence of carbonates). In addition, field observations and measurements may be refined through a range of laboratory analytical procedures that include more sophisticated evaluation of chemical, biological and physical attributes.

7.Soil moisture

 

Soil moisture deals with the percentage of water in soil.        It is important for plant and animal living. The soil moisture shows the condition of the place of the soil. The water supply,climate, soil age or soil behavior on agriculture

               

Soil Consistency Detection

To measure the consistency of the soil we had to measure  the water content in the soil. First, determine stickiness, that is, the ability of soil materials to adhere to other objects. Then, determine plasticity, that is, the ability of soil

materials to change shape, but not the volume,continuously under the influence of a constant pressure and to retain the impressed shape when the pressure is removed.

 A ) Soil Stickiness Detection

Soil from Eluvial horizon was taken to measure soil consistency. Then we test the Soil in free hand that it it had moisture or not. We found the soil had a low percentage of  water. This means our soil had a great parentage of clay partials which is around 60%

B ) Soil moisture detection

TO measure the moisture in the soil we took another sample of soil and tried to crush it with a free hand. We found our soil is easily breakable which means the soil is very friable.

8 Soil PH

The soil pH is a measure of the acidity or basically in soils. PH is defined as the negative logarithm (base 10) of the activity of hydrogen ions (H+) in solution. It ranges from 0 to 14, with 7 being neutral. A pH below 7 is acidic and above 7 is basic. Soil pH is considered a master variable in soils as it controls many chemical processes that take place. It specifically affects plant nutrient availability by controlling the chemical forms of the nutrient. The optimum pH range for most plants is between 6 and 7.5, however many plants have adapted to thrive at pH values outside this range.

9.Soil pore Space

A pore is not simply a void in the solid structure of soil. There are three main categories for pore sizes that all have different characteristics and contribute different attributes to soils depending on the number and frequency of each type.

Macropore:

The pores that are too large to have any significant capillary force. These pores are full of air at field capacity. Macropores can be caused by cracking, division of peds and aggregates, as well as plant roots, and zoological exploration. Size >75 μm.

Mesopore:

The pores filled with water at field capacity. Also known as storage pores because of the ability to store water useful to plants. They do not have capillary forces too great so that the water does not become limiting to the plants. These mesopores are ideally always full or contain liquid to have successful plant growth. The properties of mesopores are highly studied by soil scientists to help with agriculture and irrigation. Size 75 μm–30 μm.

Micropore:

The pores that are filled with water at permanent wilting point. These pores are too small for a plant to use without great difficulty. The water associated is usually adsorbed onto the surfaces of clay molecules. The water held in micropores is important to the activity of microbes creating moist anaerobic conditions. The water can also cause either the oxidation or reduction of molecules in the crystalline structure of the soil minerals. Size <30 μm.

10 . Soil drainage

Pore space controls soil drainage characteristics.  In other words, drainage problems often arise from lack of large-sized pores.In soils dominated by large pores (i.e., sandy soils), water moves rapidly.  Soils that allow rapid leaching (water movement down through the soil profile) also pose environmental hazards because rain or irrigation water moving through the soil profile takes water-soluble pollutants with it.  Ground water pollution is a sensitive issue on coarse-textured sandy soils.In comparison, in soils dominated by small-sized pores (i.e., compacted soils and soils with greater than 20% clay content), water is slow to move or may not move at all.  Soils easily waterlog.

11.Soil Consistence

Soil consistency is the strength with which soil materials are held together or the resistance of soils to deformation and rupture. Soil consistency is measured for wet, moist and dry soil samples. For wet soils, it is expressed as both stickiness and plasticity, as defined below. Soil consistency may be estimated in the field using simple tests or may be measured more accurately in the laboratory.

12  Soil Structure

Structure refers to the arrangement of soil particles. Soil structure is the product of processes that aggregate, cement, compact or unconsolidate soil material. In essence, soil structure is a physical condition that is distinct from that of the initial material from which it formed, and can be related to processes of soil formation. The peds are separated from the adjoining peds by surfaces of weakness. To describe structure in a soil profile it is best to examine the profile standing some meters apart to recognize larger structural units (e.g. Prisms). The next step is to study the structure by removing soil material for more detailed inspection. It should be stressed that soil moisture affects the expression of soil structure. The classification of soil structure considers the grade, form, and size of particles.

13 Bulk density

The bulk density of soil depends greatly on the mineral make up of soil and the degree of compaction. The density of quartz is around 2.65 g/cm3 but the bulk density of a soil may be less than half that density.Most soils have a bulk density between 1.0 and 1.6 g/cm3 but organic soil and some friable clay may have a bulk density well below 1 g/cm3Core samples are taken by driving a metal core into the earth at the desired depth and soil horizon. The samples are then oven dried and weighed.

Bulk density = (mass of oven dry soil) /volume

The bulk density of soil is inversely related to the porosity of the same soil. The more pore space in a soil the lower the value for bulk density.

14 Eluvium

Eluvium is material displaced across a soil profile, from one layer to another one, by the action of rainwater. The removal of material from a soil layer is called eluviation. The transport of the material may be either mechanical or chemical. The process of deposition of eluvium is termed illuviation.

15  Alluvium

Alluvium is loose, unconsolidated (not cemented together into a solid rock) soil or sediments, which has been eroded, reshaped by water in some form, and red posited in a non-marine setting. Alluvium is typically made up of a variety of materials, including fine particles of silt and clay and larger particles of sand and gravel. When this loose alluvial material is deposited or cemented into a lithological unit, or lithified, it would be called an alluvial deposit.