Intro Soils - Lecture 1

Introduction to Soils Instructor: Kitty O’Neil

AGPS 1103 - Soils • 3 credits, lecture & lab each week • Syllabus – Contact info – Textbook – Brady & Weil, lab manual – Course outline, exams, grading – Land Use project for 1 square mile, group • 10 different NYS soils • Objectives of AGPS 1103…

Lecture 1 - overview • Importance of soil – Soil functions • Definition of soil • Soil formation, weathering – Parent materials – Soil formation processes – Soil differs from parent material • Components of soil – Mineral, organic, air, water • Soils vary in space and in time

Why do we care about soil? ?

Why do we care about soil? • Soil resources were and are a central factor in shaping human history and development. • Survival of humans and animals is dependent on light, water, air and soil. • Good, productive soil is a basic human need. – Grow our food, clean our water, clean our air

Why do we care about soil? “All civilization is basically dependent upon natural resources. All natural resources …are soil or derivatives of soil. Farms, ranges, crops and livestock, forests, irrigation water, and even water power resolve themselves into questions of soil. Soil is therefore the basic natural resource.” - Aldo Leopold, Erosion and Prosperity, 1921

Why do we care about soil? • “Man—despite his artistic pretensions, his sophistication, and his many accomplishments—owes his existence to a six-inch layer of topsoil and the fact that it rains.” - Author unknown

What does soil DO? ?

What does soil DO?’ 1. Soil serves as a natural medium for the growth of plants, 2. regulates and purifies water, 3. recycles organic wastes and nutrients, 4. provides habitat for soil organisms, and 5. serves as physical support for building and construction. = Soil functions

What is ‘soil?’ ?

What is ‘soil?’ Soil = the unconsolidated mineral and organic material on the immediate surface of the earth.

Where did soil come from? ?

Where did soil come from? Soil has been formed by 5 major factors: 1. Parent material (original form) 2. Climate (precipitation and temperature effects) 3. Macro- and microorganisms 4. Topography (elevation, slope, position) 5. Time

Where did soil come from? Parent material Climate x Organisms Topography x time Soil

Soil Formation or ‘weathering’ • Physical weathering – Expansion and contraction with temperature change – Freezing water inside rock cracks • Chemical weathering – Acid rain, hydrolysis – Dissolution of minerals in water – Oxidation and reduction • Biological weathering – Plant roots expand into rock cracks – Plant or microorganism CO2 production

Soil Formation or ‘weathering’ from Brady & Weil, The Nature and Properties of Soils, Prentice-Hall publ.

Soil Formation or ‘weathering’

Weathering varies with topography From Smith, et al, Soil, in AccessScience@McGraw-Hill, http://www.accessscience.com, DOI 10.1036/1097-8542.631500; after Simonson et al., Understanding Iowa Soils, Brown, 1952

Soil originated from ‘parent material’ As a result of weathering, soil differs from the parent material : a) physically, b) chemically, c) biologically, and d) structurally. …this is an ongoing process…

What is ‘soil?’ ?

Soil = solids + pore space Composition of typical soil, by volume From Univ. of Massachusetts Extension Vegetable Program, Soil Basics, part I

Mineral particles 0.05 – 2.0mm, don’t stick together, gritty 0.002 - 0.05mm, smooth when wet <0.002mm, sticky when wet, hard clods when dry > 2.0mm = Gravel from Hillel, 1998, Environmental Soil Physics, Academic Press

Solids = Mineral + Organic Matter from Hillel, 1998, Environmental Soil Physics, Academic Press

Pore space = air + water

Soils vary widely from Essential Soil Science, Ashman & Puri, 2002, Blackwell Publ.

Soils vary widely Parent material  Variable Climate x Organisms  Variable Topography x time Soil  Really Variable

Soils vary widely

Questions?

Intro Soils - Lecture 1

by Kitty O'Neil on May 25, 2010

Accessibility

Categories

Upload Details

Usage Rights

2 Embeds 6

Statistics

Intro Soils - Lecture 1 — Presentation Transcript

http://www.slideshare.net	3
http://www.connecticutpreppersnetwork.com	3