Soil Properties, Soil Porosity, Bulk Density and Particle Density
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The presentation by Rabeka Sultana Shilpi focuses on soil properties, including soil thickness, composition, and essential characteristics such as soil density, porosity, and structure which influence plant growth. It outlines different soil horizons and their respective features, emphasizing the physical and chemical properties of soil, including texture, consistency, and cation exchange capacity. Key measures discussed include pH levels, which affect nutrient solubility and microbial activity, highlighting the importance of understanding these properties for effective soil management.
Soil Properties, Soil Porosity, Bulk Density and Particle Density
- 1. RABEKA SULTANA SHILPI STUDENT ID : ER-18017 SESSION :2017-2018 DEPARTMENT OF ENVIRONMENTAL SCIENCE AND RESOURCE MANAGEMENT WELCOME TO MY PRESENTATION
- 2. My Presentation On • Soil Properties • Soil Density • Soil Porosity • Soil Structure
- 3. SOIL The collection of natural bodies occupying parts of the Earth‟s surface that is capable of supporting plant growth and that has properties resulting from the integrated effects of climate and living organisms ,acting upon parent material, as conditioned by topography over period of time is known as soil.
- 4. • Mineral = 45% • Air = 25% • Water =25% • Organic Matter = 5% (i)Organisms = 10% (ii)Roots = 10% (iii)Humus = 80% COMPOSITION OF SOIL
- 5. Soil properties are of two types . They are: 1.Physical properties of soil 2. Chemical properties of soil SOIL PROPERTIES
- 6. Horizon Soil color Soil texture Soil structure Soil consistence PHYSICAL PROPERTIES OF SOIL
- 7. Cation Exchange Capacity Soil Reaction (pH)
- 8. PHYSICAL PROPERTIES OF SOIL *Soil “horizons” are discrete layers that make up a soil profile. Horizon Soil “horizons” are discrete layers that make up a soil profile. Mainly soil horizon are of six types. (a) O horizon • Dominated by organic material • Dark colour • More than 20% organic matter • Layer 0-2 feet thick
- 9. (b) A horizon • Referred to as „top soil‟ or „biomantle‟ horizon • Largly consists of minerals (sant, silt and clay) • Topmost layer of mineral soil, at depths of 2-10 feet • Darker in color than layers below (c) E horizon • The leaching layer horizon • At depths of 10-15 feet • Light in color (sant and silt present) PHYSICAL PROPERTIES OF SOIL
- 10. (d)B horizon • The sub soil horizon • At depths of 10-30 feet • Rich in clay and mineral like Fe & Al • Red/Brown color due to oxides of Fe and Clay (e)C horizon • The “Saprolite” horizon • At depths of 30-48 feet (f) R horizon • Bedrock horizon • At depths of 48+ feet PHYSICAL PROPERTIES OF SOIL
- 11. PHYSICAL PROPERTIES OF SOIL COLOR Soil color is usually due to 3 main pigments • Black-from organic matter • Red-from iron and aluminium oxides • White – from silicates and salt Color can be a useful indicator of the general properties of soil , as well as some of the chemical processes that are occurring beneath the surface .
- 12. PHYSICAL PROPERTIES OF SOIL SOIL TEXTURE The relative proportion (percentage ) of sand silt clay in soil is known as soil texture. These soil particles (sand, silt and clay) have the following size ranges: • Sand = 2 to 0.05 mm • Silt = 0.05 to 0.002 mm • Clay = <0.002 mm For all mineral soils, the proportion of sand, silt, and clay always adds up to 100 percent. These percentages are grouped into soil texture “classes”, which have been organized into mentioned “textural triangle”.
- 13. PHYSICAL PROPERTIES OF SOIL SOIL SRUCTURE The arrangement of sand silt and clay in soil is known as soil structure. Soil structures are of different type . Some of them are mention in the picture.
- 14. SOIL CONSISTENCY Soil consistency is the strength with which soil materials are held together . Soil consistency measured for - • Wet soil • Moist soil • Dry soil PHYSICAL PROPERTIES OF SOIL
- 15. CATION EXCHANGE CAPACITY (CEC) Some plant nutrients and metals exist as positively charged ions, or “cations”, in the soil environment. Among the more common cations found in soils are hydrogen (H+), aluminum (Al+3), calcium (Ca+2), magnesium (Mg+2), and potassium (K+). Most heavy metals also exist as cations in the soil environment. Clay and organic matter particles are predominantly negatively charged (anions), and have the ability to hold cations from being “leached” or washed away. The adsorbed cations are subject to replacement by other cations in a rapid, reversible process called “cation exchange”. CHEMICAL PROPERTIES OF SOIL
- 16. SOIL REACTION (pH) By definition, “pH” is a measure of the active hydrogen ion (H+) concentration. It is an indication of the acidity or alkalinity of a soil, and also known as “soil reaction”. The most important effect of pH in the soil is on ion solubility, which in turn affects microbial and plant growth. A pH range of 6.0 to 6.8 is ideal for most crops because it coincides with optimum solubility of the most important plant nutrients. Some minor elements (e.g., iron) and most heavy metals are more soluble at lower pH. This makes pH management important in controlling movement of heavy metals (and potential groundwater contamination) in soil. CHEMICAL PROPERTIES OF SOIL
- 17. Bulk density can be define as the ratio of oven dry weight of soil to total volume of the soil. It can be expressed mathematically as, Bulk density = Oven dry soil weight/ Total volume of the soil
- 18. Particle density can be define as the ratio of oven dry weight of soil to total volume of the soil particle. It can be expressed mathematically as, Bulk density = Oven dry soil weight/ Total volume of the soil particle PARTICLE DENSITY
- 19. Soil porosity is the percentage of a soil that is pore space or voids . The average soil porosity is about 50% and the pores are filled with air or water depending on the moisture content.Sands have larger pores , but less total pore space than clays. If bulk density and particle density are known , the total porosity can be calculated using these values Porosity (%)= (1- Bulk density/particle density )*100