GEOL 101 Lecture Notes - Lecture 9: Gneiss, Clastic Rock, Lithosphere
Document Summary
Solid fraction of soil include minerals and organic matter minerals : vary in size and chemical composition a. i. Organic matter(5%) a. i. 1. humus : dark organic matter that results from the decomposition of organisms a. i. 1. a. Not leaf litter, it is what remains after litter and other plants/animal decay a. i. 1. a. i. a. i. 1. a. ii. a. i. 1. a. iii. Soil water held in smaller pores in soil a. iv. Important for plant growth and contains dissolved nutrients a. v. Water holding capacity of soil depends on soil texture and structure: texture (relative proportions of sand, silt, and clay. Soil texture classification based on particle size not chemical composition. Texture is important for water holding capacity, infiltration, aeration, nutrient holding capacity a. i. a. ii. a. iii. Large particles- large pore spaces, good drainage, lots of air and little water (ex. sand) Smaller particles- smaller pore spaces, poor drainage, good water holding capacity (ex. Loam: soil with a good mix of sand and clay a. iii. 1. a. iii. 2. a. iii. 3. Combo of good drainage and water holding capacity.
