FANR 3060 1st Edition Lecture 5Outline of Last LectureI. What is soilII. HydrologyIII. Soil PropertiesIV. WeatheringOutline of Current LectureI. Weathering con’tII. Soil Profile FormationIII. The 4 processesChapter 2con’tI. Weathering con’ta. Oxidation-reduction reactionsi. Involves electron transfer that causes a change in the valence state of an atom1. Ex. With iron (equation 2.5, page 14 in book)b. LeChatlier’s Principlei. Chemical equilibrium responds to external environment and shifts to the left or the right1. i.e. 2FeOOH [red] <--> Fe2O3 – H2O [ yellow] - if you add water to the equation, the right side will be “heavier,” so it will shift to the left and the soil will become yellow againThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.ii. Piedmont is red because soils are well-drainediii. Coastal Plains are yellow because soil is wetc. Solution reactioni. Anything that produces ionsii. NaCl Na+ + Cl-1. This equation always goes all the way to the right when water is added because it is very soluble2. The ions want to bond with water more than they want to bond with each otheriii. SiO2 (quartz) always goes to the left (i.e. stays as is) because it isn’t very soluble at alld. Table 2.1 – Weathering of important primary mineralsi. The examples are mostly primary minerals that weather into secondary mineralsii. All soils end up in clay minerals and iron oxides, because those are stable and will never weather (they formed the soil to start with)1. The soil in the tropics is made of thise. “residual Parent Material”i. Weathered in placeii. 50% of the land in the Piedmontf. Table 2.3 – Types of transported parent materialsi. Alluvium – youngii. Lacustrine – not in the S.E.iii. Aeolian – silty soil = Loess1. This erodes very easilyiv. Glacial till – unsorted soilv. Glacial outwash – sorted soilII. Soil Profile formationa. Soil profilei. Vertical section of soil showing all horizons present1. From little layer (O horiz) and topsoil (A horiz) down to parent material (C horiz) and unweathered rock (R horiz)ii. Upland soils1. Contain a B horiz below the topsoils that contains higher clay or iron content that the A.a. Typically not on younger landscapes or floodplains 2. Sometimes also E horiz, a low clay, leached out horiz, occurs above B and below A. b. “translocation” i. eluviation1. A & E (Top horizons)ii. Illuviation1. B (bottom)c. Bt horizoni. Clay (leaching)d. Bnhorizi. Iron movemente. Bhhorizi. Humusii. Only in the FlatwoodsIII. The 4 processesa. Losses i. Weatheringii. Soluble, washed out into oceaniii. Solution reactionsb. Transformationsi. Minerals going from primary  secondaryii. Feldspar  clays1. Hydrolysisiii. Ferromagnesium clay, oxides1. Redox reactionc. Additionsi. Plant/microbes to form humusd. Translocationi. A,E  B, clay, Fe, humuse. “Solum” = 4