Slide 1 Soil Components Slide 2 Mineral Soil Air Soil Water Organic Matter & Soil Organisms Slide 3 Soil Components Proportions for an ideal agricultural soil Slide 4 Mineral Constituents in Soils Minerals dictate the soil chemistry which influence soil pH, salinity, fertility and structure commons - wikipedia Slide 5 Primary Minerals ( sand, silt) unchanged in composition since it was formed in cooling lava coarse particle sizes contribute to air and water movement iron oxides, gypsum, quartz, feldspars, dolomite, apatite http://farm3.static.flickr.com/2466/ Slide 6 Secondary Minerals (clays) resulting from decomposition of a primary mineral - forms sheets or layers that hold most minerals for plant growth fine particle sizes <.002mm good water-holding capacity and fertility ec.gc.ca Slide 7 Slide 8 https://www.researchgate.net/figure/Atomic-structure-of-kaolinite-eg-of-11-mineral-after-Grim-25_fig8_276425492 Slide 9 Surface Area per Soil Volume sand - small total surface area per soil volume clay - tremendous amount of total surface area Slide 10 Carbonate Minerals originate in the limestone bedrock (calcite & dolomite)- dead fish, shells, laid down and left - all contain carbonates many precipitate and recrystallize in a modified form maintain an alkaline pH (>7) in soils may interfere with plant growth when in high amounts commons.wikimedia Slide 11 Air & Water Dynamic Interchange of in pore spaces https://www.britannica.com/science/water Slide 12 Soil Reservoir Water is attracted to the sides of soil particles Slide 13 Soil Water Soil Water is held against the downward pull of gravity in the pore spaces by adhesion and cohesion Here is a really dry soil. What happens if you add water? Slide 14 Pore Space diameters of soil pores range from several millimeters to less than 0.001 millimeter large pores - rapid movement of water small pores - tortuous routes for water to move Slide 15 Slide 16 Soil Air Soil Air is not interconnected - its composition varies from place to place some gases are consumed by plants and some are released CO2 concentration is often 100X higher in soil than in atmosphere www.nrcs.usda.gov Slide 17 Soil Air soil water influences air content low water content allows for more air high water content traps air in small pockets and microbes may produce toxic gases https://brinly.com/healthy-lawn-tips/aeration-process/ Slide 18 Slide 19 Slide 20 Slide 21 Soil Organic Matter residues from plants, animals and microbes influences a soil’s fertility by improving water holding capacity increases the diversity of pore sizes primary food source for soil microorganisms Slide 22 Improving soil texture replace clay with sand??? need at least 50% replacement for any change in texture usually adding sand to a fine soil will produce a CEMENT adding clay to a coarse soil?? - same result - CEMENT add Organic Matter?? - DOES NOT AFFECT TEXTURE!! BUT DOES IMPROVE STRUCTURE and tilth Slide 23 the end