Environmental science Soil Environmental science
Pre Test What is the difference between Soil Profile and Soil Horizons? 01 Which horizon accumulates organics and clays by the movement of water. 02 What are 5 soil forming factors 03 What horizons are considered Master horizons 04
Soil is made of What? 45% Mineral – Clay, Sand, Silt 25% Air – Oxygen is vital for plant growth and certain microorganisms 25% Water – Depends on porosity and precipitation 5% Organic Matter 5% Organisms (burrowing animals, bacteria, fungi, protists) 10% Roots 85% Humus Soil is made of What? NRCS Soils
Soil Texture University of Illinois Soil Science Extension Particle Size effects porosity of soil Influences water holding capacity Water availability for plants Water film around particles cannot be accessed by plants University of Illinois Soil Science Extension
Fun Fact Soils actually have a negative charge specifically clays and organic matter 1 Nutrients needed by plants are positively charged. 2 This is what we call cation-exchange or on soil samples cation-exchange capacities (CEC) 3 University of Illinois Soil Science Extension 4
Sand Silt Clay Soil Texture Lacks the capacity to hold water and nutrients Sand Increases water holding capacity Silt Smallest particle Greatest water and nutrient retention Clay U of I Rangelands p. 31
Soil Structure Arrangement of soil particles Blocky Platy Granular Prismatic Columnar Massive
Soil Structure Greatly effects the permeability of soil (water or air) Permeable Least Permeable
Soil-Forming Processes Additions – addition of organic or mineral Organic matter Wind blown matter Rainfall adds Nitrogen and other soil particulates Losses – Loss of organic or mineral Deep Leaching Surface loss Translocations – movement within soil Low rainfall areas causes saline/alkaline problems because of incomplete leaching Transformations – mineral or organic modification Organic matter to humus by microorganisms Chemical weathering of parent material (Fe -->Fe203) file:///Users/Katy2/Downloads/surdown.pdf