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58 Cards in this Set
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defined soil in a natural state composed of a mixture of - mineral particles or disintegrated rocks; - organic matter a decayed plant & animal bodies - water mostly carbon dioxide, oxygen & - air nitrogen these are in varying proportion |
Barrera 1960 |
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Brady and Weil (1999) defined soil |
-dynamic natural body -minerals -organic materials -living forms in which plants grow; -the collection of natural bodies -Occupying earth’s surface -support plants -have properties due to the integrated effect of the ff; (CLORPT) |
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Function of soil |
-plant growth medium -regulates water supply -recycles raw material -organism habitat -engineering medium |
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Approaches in study of soil |
Edaphological Pedological |
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An approach that deals in genesis, properties and classification |
Pedological approach |
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An approach that deals the relation of soils to plants |
Edaphological |
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Soil components |
⁴5% minerals 5%om 25% air 25% water |
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rocks were once in a molten state, very hot inside the earth, which were forced upward to the surface. On cooling, they solidified. |
Igneous |
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Types of igneous rock |
Intrusive Extrusive |
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In the sea are several kinds of animals covered with shells, the most important of which are corals. the accumulation of skeleton of corals that become solidified into rocks are called limestone. |
Sedimentary |
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schists, gneiss, slate, marble, igneous and sedimentary rocks, when subjected to prolonged and strong pressure and high temperature, become modified so as to appear very solid, hard and massive. |
Metamorphic |
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process that alters the physical and chemical state of the rock at or near the surface of the earth without necessarily eroding or transporting the product of alteration. |
Weathering process |
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Major type of weathering |
Physical and chemical |
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the breakdown of rocks into various fragments caused by various physical stresses. There is no change in chemical composition or no element is added nor subtracted. |
Physical weathering |
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the breakdown of chemical composition of the mineral grains that make up a rock. The process causes internal structure of original rock to be destroyed to form new minerals with new crystal structure which are stable. |
Chemical weathering |
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a vertical section of the ground from the surface down to the parent rock |
Soil profile |
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Factors of soil formation. Clorpt |
Climate Organism Relief Parent material Time |
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factor of soil formation that includes all the conditions from which it is made up, such as; temperature, rainfall and wind. |
Climate |
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Factors of soil formation that relates to the configuration of the land surface and is described in terms of difference in elevation, slope and landscape position. |
Relief/topography |
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A factor of soil formation that comprises all plants, animal and microbiological life. accumulates in wet places where plant growth exceeds the rate of residue decomposition. |
Organism |
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A factor of soil formation that the material from which the soil profile or soil material developed from the initial state. |
Parent material |
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Factor of soil formation . A soil-forming processes takes time to show their effect, and it starts when a landslide exposes new rock to the weathering environment at the surface, |
Time |
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Physical properties of soil |
Soil texture Soil structure Particle density Bulk density and pore spaces Soil moisture Soil aeration Soil color Soil temperature |
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Influence to plant of soil physical properties |
Control of root penetration Drainage Aeration Moisture retention Availability of plant nutrients |
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3 soil phases |
Solid Liquid Gaseous |
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refers to the relative percentage of the different soil separates (sand, silt and clay) |
Soil texture |
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a soil seperate that is loose and single-grained. Grains can readily be seen or felt. A handful of it when squeezed by hand will fall apart but when moist will form a lump and crumble if touched |
Sand |
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a soil seperate that is very similar to finer sand in surface exposed. Appears cloddy when dry but lumps can be readily brokenWhen wet the soil readily turns together and puddles |
Silt |
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a soil seperate that Has great capacity to adsorb water & other substances= influence on the water holding capacity . Sticky when wet and can be easily molded |
Clay |
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3 broad textural classes |
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Methods of determining soil distribution |
Mechanical analysis Field determination Textural grouping of soil |
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Importance of soil texture to plants |
Relative resistance to root penetration Infiltration of water Water holding capacity Soil fertility Soil aeration |
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refers to the arrangement of the individual soil particles that are grouped together into defined patterns |
Soil structure |
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Soil structure greatly influences: |
Water movement Aeration Heat transfer Porosity |
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Types of soil structure |
Granular Platy Blocky Columnar/ prismatic Structureless |
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A kind of soil structure that do not assume any definite form |
Structureless |
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A type of soil structure that forms a cube like block, generally found in b horizon and with good drainage, aeration and root penetration. |
Blocky |
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Type of soil structure that forms a small, rounded and loose or porous aggregates |
Granular |
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A type of soil structure with a post like appearance, common in b horizon or red soils, has a good drainage and aeration. |
Columnar |
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A type of soil structure that assumes the form of sheets one on top ofthe other lying horizon. Has poor drainage and root penetration. |
Platy |
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Soil structure. Soil particles are held together by |
Plant roots Lime Oxides of fe and Ai Colloidal om |
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Factors affecting aggregation |
Climate Vegetation Microbial activity Wetting and drying |
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Importance of structure to plants |
Permeability to water and air Have satisfactory infiltration Water retaining capacity Readily penetrated by plant roots Resist compaction by farm machineries |
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Defined as the weight per unit volume of soil particles, not including pore spaces |
Particle density |
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Method of determination of particle density |
Pycnometer method |
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Defined as the oven dry weight of the unit volume of soil including pore spaces |
Bulk density |
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Bulk density method of determination |
Core method and paraffin clod |
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Favorable physical condition |
Low bulk density |
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Diff. Of low bulk density and higher bulk density |
Low bulk density has lowerweight and has more pore spaces Higher bulkdensity has higher weight and less pore spaces |
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Refers to the percentage ofof soil volume occupied by pore spaces |
%porespace or porosity |
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Defined as the interchange of gases(02) of the soil atmosphere with those of the free atmosphere above the soil |
Soil aeration |
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0² is important in |
Respiration Proper functioning of roots and soil micro organism Om decomposition and release of nutrient Reduction of Fe, Mn and Sulfate |
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– has little effect on soil behavioreffect on gain & loss of radiant energy guide to extent of weathering guide to amount and distribution of O.M.- guide to state of aeration & drainage |
Soil color |
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influences the chemical & biological activity in soil - Regulates soil - air movement |
Soil temperature |
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Amount of heat enteeing the soil are regulated by |
Climate soil color Altitude and aspect of land Vegetative cover |
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different soil have different capacity to hold water and may contain different amount of water at different times |
Soil moisture |
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Soil moisture. Roots of plant and micro organism will die bcs of lack of oxygen |
Too much water |
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Soil moisture. Plant growth slows down then wilting happens . |
Too little water |
