ENV 101 Lecture Notes - Lecture 14: Soil Series, Subsoil, Soil Salinity
Document Summary
Soil is contained in the crust of the earth: uppermost layer, average thickness: oceans (5 miles), continents (20 miles, supports plants, animals, microbes, crust is about a thick to earth as skin of apple is to an apple! Soil comes from soil forming factors: parent material = bedrock, topography, organisms, climate, time. Soil is dynamic: changes composition and moisture with depth and time, physical and biological forces break down and rearrange parent material through mechanical and chemical weathering. Healthy soil provides: substrate, habitat for living organisms, managed moisture, nutrients, plant growth, foundation of ecosystems. Organic material 5: leaf litter, animal dung, dead remains of plants and animals. Mineral particles 45: weathered rock. Pore space: half of soil is not soil, soil air, soil water. Particle size determines the pore space: larger particles have larger pores, water drains quicker through this soil. Soil texture: relative proportion of sand, silt, clay. Soil texture affects soil properties: large particles.
