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Soils and Water, Spring 2009

Lecture 1: Introduction to Soils 1

11:375:360 Soils & Water

Instructor:Dr. Daniel Giménez; [email protected]

Brady, N. C. and R. R. Weil. 2002. Elements of the Nature and Properties of Soils. Prentice Hall.

There is no Lab Manual. Lab instructions will be posted in the course web site.

Text

Teaching Assistant:Jen Loudon; [email protected]

11:375:360 Soils & Water

• Web site:– http://envsci.rutgers.edu/courses/index.shtml

(follow the link “Soils and Water”).

• Grades:

25%Laboratory

20%Final Project

25%Final Exam

20%Assignments and Quizzes

10%Homeworks

Questions

• How do societies benefit from soils?

• What is the difference between soil and dirt?



Source: Costanza et al. 1997. The value of the world’s ecosystem services and natural capital. Nature 387: 253-260.

The Value of Ecosystem Services• Most of the value of

ecosystem services is outside the market.

• For the entire biosphere, the global values is between US$ 14-54 trillion per year, while global gross national product is about US$ 18 trillion per year.

• How would the global economical situation change if we had to produce or pay for ecosystem services?

Source: Costanza et al. 1997. The value of the world’s ecosystem services and natural capital. Nature 387: 253-260.

Taking Soil Science to Outer Space:The Phoenix 2007 Scout Mission to Mars



Distribution of Water in Mars

Phoenix Scout Mission to Mars

• Mission Goals:– Search for subsurface ice and clues to its origin– Search for evidence of past or episodic liquid water.

• The Mission:

• Phoenix lands in northern spring above the “arctic circle,” and will operate ~90 days through the summer solstice

• Phoenix’ robot arm can excavate 50-100 cm, with “ripper tines”to sample hard ice/rock conglomerates.

– Odyssey predicts that ice will be found 20-40 cm below surface..

• Soil will be analyzed for thermal and geochemical properties.

Some of the Instruments in the Phoenix

Optical and Atomic Force MicroscopeProperties: soil porosity, aggregation, cementation effects, crystal forms, chemical surface textures and coatings on grains, ice coatings on grain nuclei, grain size and shape distribution, and surface textures on grains

Wet Chemistry LabSensors include pH, dissolved CO2 and O2 (ppm level); Dissolved K+, NH4+, Na+, Li+, Ca2+, Mg2+, Cd2+, NO3-, Cl-, ClO4-, I-, Br-, and Ag+/S- (ppm level). Cyclic voltammogram (CV) of redox species. Anodic stripping voltammetry analysis (ASV) of metals such as Hg, Pb, Zn, Fe, and Cu (ppb level).

Thermal and Electrical Conductivity Probe (TECP)

The TECP will probe the soil with of 4 needles, ~30 mm long, arranged in a row, performing measurements as a function of depth in 1 cm increments. It will…Measure temperature from 173-303K and soil electrical conductivity. Determine thermal conductivity and heat capacity



The Atacama Desert

Soils and Societies• Societies greatly depended on soils for their

development.• Perception changed when the population of

industrialized countries concentrated in cities: soils became a nuisance associated to diseases and death (“Dirt, Disease, and Death”).

• Today’s perception about soil is negative overall. The roots for this can be traced to the nature of soils as well as to cultural issues.

Concepts Related to Soils

• Medium for plant growth: production of food and fibers

• Construction material• Environmental Filter• Other uses:

– Medicinal: pharmaceutical, treat gastrointestinal disorders, soils are a source of antibiotics (e.g., streptomycin)



Agriculture and Soils

Roles of Soil• Supporting plant growth:

– food production (agriculture)– recreation (golf greens)

• Recycling waste products:– nature – society

• Providing habitat for a large variety of organisms.

• Controlling flow of water.• Construction material.



Urbanization and Soils

Urbanization in the USA• Impervious surfaces alter

the basic functions of soils:

– Energy storage and exchange (“heat islands”).

– Reduce carbon sequestration (less vegetation).

– Increase runoff (less infiltration).

• In the USA:– Population increases at

a rate of 3 m/year.– $418 billion in

construction spending.– About 6% of urban

land were converted in the period from 1982 to 1997 (6,750 km2).

Source: Elvidge, C. D., C. Milesi, J. B. Dietz, B. T. Tuttle, P. C. Sutton, R. Nemani, and J. E. Vogelmann (2004), U.S. Constructed Area Approaches the Size of Ohio, Eos Trans. AGU, 85(24), 233.

Area Covered With Turf Grasses• According to Milesi et al. (2005),

1.9% of the surface area of the USA is covered with lawns (residential, industrial, and recreational). This area is 3 times larger than any single irrigated crop.

• In New Jersey, the estimated area covered with turf grasses is about 4,000 km2 or 18% of the surface of the State.

Source: Milesi et al. 2005. Mapping and Modeling the Biogeochemical Cycling of Turf Grasses in the United States. Environmental Management 36: 426-438.



The Geological Cycle

Magma rises to the surface and solidifies.

The rock reaches the surface. Soil on the surface of therock is non existent or very thin.

Erosion wears away the rock.

Source: Singer and Munn. 1999. Soil: An Introduction

Geomorphic Cycle

Definition• Soil is “the unconsolidated mineral or organic matter

on the surface of the earth that has been subjected to and influenced by genetic and environmental factors of parent material, climate (including water and temperature effects), macro- and microorganisms, and topography, all acting over a period of time and producing a product—soil—that differs from the material from which it is derived in many physical, chemical, biological, and morphological properties and characteristics.”



Ecosystems and Soils

• An ecosystem is an aggregate of plants, animals, and microbes plus the environment in which they live.

• We only deal with finite ecosystems with arbitrary boundaries.

• Terrestrial ecosystems are those that include soil within their boundaries.

• Aquatic ecosystems do not include soil.

©2004 Pearson Education, Inc.Pearson Prentice HallUpper Saddle River, New Jersey 07458

ELEMENTS OF THE NATURE AND PROPERTIES OF SOILS, 2/eNyle C. Brady and Ray R. Weil

The Soil as an Open System



Soil Profile: Vertical DifferentiationMass and energy fluxes through a soil result in layers parallel to the soil surface: HORIZONS

Chatsworth, NJ Eastern Montana, MT

Soils and Ecosystems

Source: Wright, R.T.2002. Environmental Science

Soils and Ecosystems

1998 Wadsworth Publishing Company, Inc.



Natural Color Mosaic of North America

Source: http://visibleearth.nasa.gov/

Ecosystem Distribution (USA)

Source: The State of the Nation’s Ecosystems (www.heinzctr.org/ecosystems/report.html)



Soil Types (USA)

Soil-landscape relationship

Gains < losses



Gains > losses

Overview• Soils exchange matter and energy with the

surrounding environment, i.e., atmosphere, biosphere, hydrosphere, and lithosphere.

• The development of soil profile is determined by a balance (gains vs. losses) between input and output of matter and energy.

• Concepts to remember: horizons, soil profile.

Soil Description

Soils are described by exposing a vertical plane and describing various features for each horizon.



Soil Morphology

Solid

LiquidAir

Soil Morphology• Soil morphology can be studied at different scales

Concept of Soil Structure

Tilled soilStructureless

Structured: “blocky”



Soil Structure

Figure 4.25 in Element of the Nature and Properties of Soils (Diagram courtesy of R. Weil).

Granular

Blocky



Platy

Prismatic

Structureless

• Single grain

• Massive



Where in the Profile?

AirWaterMineralOrganic

Volume Percentages of Soil Components

An ideal soil is only 50% solid material !

Volume and Weight Base Percentages for Soil Components

Comp. Vol. cm3

Dens. g/cm3

Mass g

% totalmass

Air 25 0 0 0

Water 25 1.0 25 17

Min. 45 2.65 119.3 81.3

Org. 5 0.5 2.5 1.72

total 100 --- 146.8 100



Figure 4.10 Bulk density Db and particle density Dp of soil. Bulk density is the weight of the solid particles in astandard volume of field soil (solids plus pore space occupied by air and water). Particle density is the weight of solid particles in a standard volume of those solid particles. Follow the calculations through carefully and the terminology should be clear. In this particular case, the bulk density is one-half the particle density, and the percent pore space is 50.

Concept of Soil Structure

Tilled soilStructureless

Structured: “blocky”Soil Particles

Soil Aggregates

2 μm

500 μm

Soil Particles

sand

clay

silt Fine sand Medium sand

Coarse sand

NOTE: Clay is not visible



Overview

• Soils are porous material composed by solid (i.e., mineral and organic matter) and pore space.

• The pore space contains either air or water.• Concepts to remember: soil aggregates, soil

particles.

Soil Composition: Minerals

Property Sand Silt Clay

Size range (mm) 2.0-0.05 0.05-0.002 <0.002

Surface activity low medium high

Clay

Soil Composition• Soil organic matter

– includes living and nonliving macro and micro organisms.

– great influence in the physical, chemical, and biological soil properties.

– Humus is stable organic material that has been transformed by soil microorganisms.

– Microorganism population is very diverse. It is estimated that about 4000 different bacterial species can be found in a gram of soil.



Soil Composition• Air

– several times more concentrated in CO2 than atmospheric air.

– amount and composition of soil air determined mainly by soil water content and biological activity.

• Soil solution– the soil solution (a.k.a. soil water) contains a

large amount of dissolved substances.– soil water is the major transport agent of

substances in the soil.

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