General Soil Information

Soil Notes

Definition_______– relatively thin _______layer of the Earth’s ______ consisting of _______ and _____ matter that is affected by agents such as weather, wind, water, and organisms.

____________

Organisms, mainly microorganisms, inhabit the soil & depend on it for _______, ______ & ______.

______ anchor themselves into the soil, and get their ________ and ______. Terrestrial plants could not survive without soil, therefore, ______ could not _____ without soil either.

SOIL: A _____________ RESOURCE

Soil is a slowly ______ resource that provides most of the ________ needed for plant growth and also helps purify water.

Soil formation begins when bedrock is broken down by physical, chemical and biological processes called ___________.

________ soils, or soils that have developed over a long time are arranged in a series of horizontal layers called _____ _______.

Parent MaterialThe rock that has slowly broken down into smaller particles by __________,_________, and __________weathering.

To form 2.5 cm (1 in.) it may take from _________ years.

_____________ – 4 Distinct Parts___________particles (45% of “typical” soil)

_________matter (about 5%)

_______(about 25%)

_______ (about 25%)

Soil Formation

____________

_______ Weather

Ex. erosion (wind, water, ice, etc.)

_________Weather

A plant’s roots or animal cells undergo cell respiration and the CO2 produced diffuses into soil, reacts with H2O & forms carbonic acid (H2CO3). This eats parts of the rock away.

Renewable or Not?

___________ produces new soil

But, in the ________ rainforests, all of the nutrients are caught in the trees and when cut down & burned the soil _____ get the nutrients back.

________The percentages (by weight) of different sized particles of ____, _____ and ____ that it contains.

Soil Properties:

____________ of soil depends on

how soil particles are __________

and _________together

(sand, silt, clay)

Texture (Cont.)

>___mm in diameter = ________ (not actually considered soil because it doesn’t have direct _____ to plants.

________mm = ______ (the largest soil particles) can be seen easily with the eye.

__________mm = ____ – about the size of flour and barely visible with the eye.

<______mm = ______ (has the greatest surface value) – only seen under and electronic microscope.

_________

To tell the ____ in soil, take the soil, _____ it, and ___ it between your fingers and thumb.

_______ -has a lot of sand______- high clay content and you should

be able to roll it into a clump _____- smooth, like flour.

*What type of soil do you have? _____

_________

How easily the soil can be ________.

_________

A measure of the _______ of soil and the average ________between the ________.

____________The ____ at which water and air moves from ______ to _____ soil layers. It is ______ between those spaces.

Some Soil _________

Soils _____ in the _____ of the particles they contain, the amount of _____ between these particles, and how rapidly _____ flows through them.

______-______ Potential

Some soils, like ______, ____ when ____ gets in them, then they ____ and crack. This is ___ for house _________, etc.

_____

The pH of most soils ranges from ___ to _____.

But, the soil of the _______ Forest in California is extremely _______ (2.8-3.9) and in _____ Valley, California, it is very _____ (10.5).

_______ are affected by ____ because of the solubility of ________ minerals.

________

Steep slopes often have _____ or ___ soil on them because of ________.

_____ from precipitation tends to _____ the slope also. ______ slopes and ____ may ______ the formation of deep ____.

______

Some soils are very _____ (like in some places in San Antonio). It can be only ____ inches of soil and then you hit _____. Other areas can have soil ___ inches deep or more.

______

____ soil is rich with lots of ______ matter.

______ soil (like sand) is not so rich with very _____ organic matter.

Soil ________

_______ Layer (___-horizon)

The ________ layer; it is ___ in organic material.

Plant _____ accumulates in the O-horizon and _______decays.

In _______ soils the O-horizon is completely ______, but in certain organically rich soils it may be the dominant layer.

________ (___-horizon)

It is _____ and rich in accumulated organic _____ and ______.It has a _____ texture and is somewhat ________ due to the ____ of many nutrient minerals to deeper layers and by _______.

________ (___-horizon)The ______-colored subsoil beneath the A-horizon; it is often a zone of ________ where ______ minerals have _____ out of the topsoil and litter accumulate. It is typically ____ in _____ and ________ compounds and clay.

_______ Material (___-horizon)

This contains _______ pieces of ____ and borders the ______ solid parent material. Most ______ do not go down this deep and it is often ______ with groundwater.

Fig. 12-A, p. 284

Fern

Mature soil

Honey fungus

Root system

Oak tree

Bacteria

Lords and ladies

Fungus

Actinomycetes

Nematode

Pseudoscorpion

Mite

RegolithYoung soil

Immature soil

Bedrock

Rockfragments

Moss and lichen

Organic debrisbuilds upGrasses and

small shrubs

Mole

Dog violet

Woodsorrel

EarthwormMillipede

O horizonLeaf litter

A horizon

Topsoil

B horizonSubsoil

C horizon

Parent material

Springtail

Red Earth Mite

_______ in Mature Soils

_________: the _______ movement of _____ through soil.

_________: dissolving of _____ and organic matter in upper layers carrying them to lower layers.

The soil _____ determines the _______ of _______ and ________.

Mosaic of closely packed pebbles, boulders

Weak humus-mineral mixture

Dry, brown to reddish-brown with variable accumulations of clay, calcium and carbonate, and soluble salts

Alkaline, dark, and rich in humus

Clay, calcium compounds

Desert Soil(hot, dry climate)

Grassland Soilsemiarid climate)

Tropical Rain Forest Soil(humid, tropical climate)

Acidic light-colored humus

Iron and aluminum compounds mixed with clay

Deciduous Forest Soil(humid, mild climate)

Forest litter leaf moldHumus-mineral mixtureLight, grayish-brown, silt loamDark brown firm clay

Coniferous Forest Soil(humid, cold climate)

Light-colored and acidic

Acid litter and humus

Humus and iron and aluminum compounds

Case Study: _________ Food Production in the United States

Industrialized agriculture uses about ____ of all commercial ______ in the U.S. and food travels an average ______ kilometers from farm to plate.

_________ Agriculture: Low Input ___________Many farmers in developing countries use ____-______ agriculture to grow a variety of crops on each plot of land (__________) through:

__________ ________: planting several genetic varieties.

____________: two or more different crops grown at the same time in a plot.

___________: crops and trees are grown together.

_________: different plants are planted together.

________ is the movement of _____components, especially surface litter and topsoil, from one place to another.

______ billion tons of soils are eroded from the U.S. each year; this would fill 320 million average-sized dump trucks that, if parked end-to-end, would extend to the moon and ¾ of the way back!

________

__________

In undisturbed ecosystems, the _______ of plants help ________ the soil, and usually soil is not lost faster then it forms.

But, _______, _______, _______, _________ by livestock, _________, deliberate ________ of _________ etc. destroy plant cover and leave soil vulnerable to erosion. This ______ in a few _______ what nature took ________ to _________of years to produce.

SOIL ________ AND ___________

Soil erosion lowers soil ______ and can overload nearby bodies of ______ with eroded ________.

______ erosion: surface water or wind peel off thin layers of soil.

_____ erosion: fast-flowing little rivulets of surface water make small channels.

______ erosion: fast-flowing water join together to cut wider and deeper ditches or gullies.

SOIL ________ AND __________

Soil erosion is the movement of soil components, especially surface litter and topsoil, by ____ or ______.

Soil erosion increases through activities such as farming, logging, construction, overgrazing, and off-road vehicles.

Figure 12-12Figure 12-12

Global Outlook: Soil Erosion

Soil is eroding _______ than it is forming on more than ________ of the world’s __________.

Fig. 12-16, p. 289

Case Study: Soil Erosion in the ____ – Some Hopeful Signs

Soil erodes faster than it forms on most U.S. cropland, but since _____, has been cut by about _____.

1985 _____ _______ _____ (Farm Act): farmers receive a _____ for taking highly erodible land out of _______ and replanting it with soil saving plants for _______ years.

Water Erosion_______ – water hits the soil at a ______ angle (based on _____)

This can erode soil.

_____ – when surface water moves down a _____ or across a _____ in a wide flow and peels

off fairly uniform sheets of soil.

Because the topsoil disappears _____, sheet erosion may ____ be _______ until too much

_______ has been done.

Water Erosion (Cont.)

_______ Slippage – (like in California) where it is very _____ and large amounts of _____ slip away in large _____ (_____ slides).

_____ – concentrated flow across the surface of soil. Leaves ______ (micro

channels).

_______ – rivulets of fast-flowing water join together and, with each succeeding rain, ____ the _______ wider and deeper until they become ______ or ______. Gully erosion usually happens on ____ ______ where all or most vegetation has been removed.

_______ Erosion

______ – one particle hitting another and being blown across the surface of the soil.

_________ – airborne soil. Ex. soil from Lubbock is found in Temple, Texas.

______ Creep – _________ dunes; surface creeping slowly across. __________ are an example of a very fast surface creep.

Desertification: Degrading Drylands

__________ of world’s land has lost some of its productivity because of ________ and human _________ that reduce or degrade topsoil.

Human agriculture accelerates _____________Dust bowl in U.S. due to severe wind erosion of topsoil

___________________Decrease:

• Population growth• Overgrazing• Deforestation• Destructive forms of planting, irrigation, and mining

Both _______ and ________

going through Desertification

We Can Reduce Desertification

_________ and _________

Repeated -________ can reduce crop yields by causing _____ buildup in the soil and waterlogging of crop plants.

Soil ______________Gradual ____________of _______ in the soil from irrigation water

________ crop yields and can even kill plants

Affects _____% of world croplands

_____________ Irrigation water gradually ________water table

Can prevent roots from getting __________

Affects ____% of world croplands

___________ Irrigation Has Serious ______________

CleanupPrevention

Soil Salinization

Solutions

Reduce irrigation

Switch to salt-tolerant crops (such as barley, cotton, sugarbeet)

Flush soil (expensive and wastes water)

Stop growing crops for 2–5 years

Install underground drainage systems (expensive)

Use more efficient irrigation methods

Fig. 12-29, p. 307

Salinization and Waterlogging of Soils: A ________ of Irrigation

Example of ____ _________, poor drainage, and severe _________.

White _______ salts have _______ crops.

Figure 12-17Figure 12-17

Soil ______________Terracing

Contour planting

Strip cropping with cover crop

Alley cropping, agroforestry

Windbreaks or shelterbelts

Conservation-tillage farming

Identify _________ hotspots

Many Farmers Are Reducing Soil Erosion

Erosion _______

_________ – can reduce _______ erosion. Long rows of ______ are planted to partially _____ the ____. They can also help ____ soil _______, supply some _____ for fuel, and provide _____ for birds.

______________ AGRICULTURE THROUGH SOIL CONSERVATION

Modern farm __________ can plant crops without disturbing _______ (no-till and minimum tillage.

_____________tillage farming:• Increases ________ yield.• Raises soil __________ content.• _________ water use.• Lowers __________.• Uses less tractor ________.

________ Tillage – (conservation tillage) to disturb the soil as little as possible while planting crops.

______ tillers break ___and _____ the _______ soil _____ turning over the _______, previous crop residues, and any cover vegetation.

SUSTAINABLE AGRICULTURE THROUGH SOIL CONSERVATION

________, _______ planting, ____ cropping, _____ cropping, and ________ can reduce soil erosion.

Figure 12-26Figure 12-26

________ Farming –sloping your growing crops, etc.

_________ are run ______ parallel to the ground to stop soil from running down a steep slope. Plowing and planting crops in _____ across, rather than up and down, the sloped contour of the land.

_______ – (what you use for contour farming.) Dirt goes up to hold the dirt in place. Broad, nearly ______ terraces that run across the land contour. Helps to retain ______ for crops at each level and _____ soil ______ by controlling ______.

______ Cropping- a row crop such as corn alternates in strips with another crop that completely covers the soil, reducing erosion.

catches and reduces water runoff and helps prevent the spread of pests and plant diseases.

_______ Cropping (________ cropping) – several crops are planted together in strips or alleys between trees and shrubs that can provide shade (which reduces water loss by evaporation) and helps to retain and slowly release soil moisture.

Irrigation __________

Conventional __________ irrigation- allows _____of the water input to reach crops

_______-flow irrigation- Valves that send water down irrigation ditches.

_____ irrigation- Can raise water efficiency to ______and reduce water use by _____.

________ irrigation- allowing the natural floods to irrigate the crops. _____ in flood zones tend to be nutrient _____ and ______.

______________

___________ are ______ in atomic structure. Ex. ______, _________ & _________.

____________

These are ______ in atomic structure. Plants need them in _____ amounts.

Ex. ________, _____ & ____.

Soil __________

_________ and _____________ Fertilizers – animal ______, crop residues, bone meal, and compost

_______ Fertilizers –________ from chemical compounds

________ – exact ________are _____; they are soluble & thus immediately available to the plant

_____– quickly ____ away; this _____ the ______; doesn’t help the water holding capacity of the soil like organic fertilizers do.

Growing plants in _________ _______

suspending plants in water while not using soil• Ex. ___________are grown this way.

____________

can ___________ the environment & grow plants where there is no soil; NASA is looking into this.

_______

labor-intensive and expensive

____________

SUSTAINABLE AGRICULTURE THROUGH SOIL CONSERVATIONFertilizers can help _______soil nutrients, but runoff of inorganic fertilizers can cause water ______________.

__________ fertilizers: animal manure, plant or green manure or compost.

Commercial ___________fertilizers: Active ingredients contain nitrogen, phosphorous, calcium, potassium and other trace nutrients.

______rotation: planting different crops every year to restore nutrients to soil that one crop may take out which next one restores

THE ______ REVOLUTION AND ITS ENVIRONMENTAL IMPACT

Since 1950, high-_____ agriculture has produced _____ crops per unit of land.In 1967, fast growing _____varieties of rice and wheat were developed for ______ and ________.

Figure 12-7Figure 12-7

THE GREEN REVOLUTION AND ITS ENVIRONMENTAL IMPACT

Lack of _____, high ____ for small farmers, and physical limits to increasing crop yields ______ expansion of the ______ revolution.

Since 1978 the amount of ______ land per person has declined due to:

Depletion of underground ____ supplies.

_________irrigation methods.

_____ build-up.

_____ of irrigating crops.

THE GREEN REVOLUTION AND ITS ENVIRONMENTAL IMPACT

Modern ________ has a greater ______ environmental impact than any ______ activity.

Loss of a variety of ________ different ____ and ______ strains might limit raw material needed for _____ green and _____ revolutions.

• E.C. Think GMOs!! What are they? ________________

In the U.S., 97% of the food plant varieties available in the 1940 no longer exist in large quantities.

Fig. 12-10, p. 289

Biodiversity Loss Soil Water Air Pollution Human Health Loss and degradation of grasslands, forests, and wetlands

Erosion Water waste Greenhouse gas emissions from fossil fuel use

Nitrates in drinking water

Loss of fertility Aquifer depletion

Pesticide residues in drinking water, food, and air

Salinization Increased runoff and flooding from cleared land

Other air pollutants from fossil fuel use

Fish kills from pesticide runoff

Waterlogging

Sediment pollution from erosion Greenhouse gas

emissions of nitrous oxide from use of inorganic fertilizers

Contamination of drinking and swimming water with disease organisms from livestock wastes

Desertification

Killing wild predators to protect livestock

Fish kills from pesticide runoff

Surface and groundwater pollution from pesticides and fertilizers Belching of the

greenhouse gas methane by cattle

Loss of genetic diversity of wild crop strains replaced by monoculture strains

Bacterial contamination of meat

Overfertilization of lakes and rivers from runoff of fertilizers, livestock wastes, and food processing wastes

Pollution from pesticide sprays

THE _______ REVOLUTIONTo ______ crop yields, we can ___ the _____of similar types of organisms and mix the genes of different organisms.

________selection has been used for centuries to develop genetically improved varieties of crops.

Genetic _______develops improved strains at an exponential pace compared to artificial selection.

Controversy has arisen over the use of genetically _______ food (GMF/GMOs).

______ _____

Genetic engineering involves ______ a ____ from one species and _______ the DNA into another species.

Figure 12-18Figure 12-18

PRODUCING MORE _______

About _____ of the world’s ____ is produced by livestock grazing on _____.

The other half is produced under ______-like conditions (_______).

Densely packed livestock are fed ____ or fish meal. *Why should cows not be feed corn?_________________________

Eating more _____ and farm-raised ____ and less beef and pork ______ harmful environmental ______ of meat production.

Fig. 12-19, p. 295

Trade-Offs

Animal Feedlots

Advantages Disadvantages

Increased meat production

Need large inputs of grain, fish meal, water, and fossil fuelsHigher profits

Concentrate animal wastes that can pollute water

Less land use

Reduced overgrazing

Reduced soil erosion

Antibiotics can increase genetic resistance to microbes in humans

Help protect biodiversity

How Many People can the World Support? Food ________ and ___________

The number of people the world can support depends mostly on their ____ capita ___________ of _____ and _____ and how many _______ couples have.

Research has shown that those _____ very ___ on the food chain or very _____ on the food chain ____ ____ _____as ______ as those that live somewhere in between.

PRODUCING MORE MEAT

_________ of converting grain into animal protein.

Figure 12-13Figure 12-13

CATCHING AND RAISING MORE ______ AND ____________

After spectacular increases, the world’s ____ and ____ capita ______ and ________ fish and shellfish catches have _______ off.

Figure 12-9Figure 12-9

CATCHING AND RAISING MORE FISH AND SHELLFISH

Government ________ given to the fishing ________ are a major _____ of _________.

Global fishing industry spends about $___ billion per year more than its catch is worth.

________ subsidies many fishing ______would have to go ____ of __________.

____________ allow excess fishing with some keeping their jobs longer with making less money.

__________: Aquatic Feedlots

_______ large numbers of ____ and _______ in ponds and cages is world’s fastest growing type of food production.Fish farming involves ________ fish in a ________ environment and ________ them in captivity.Fish ranching involves holding _________ species that live part of their lives in _______ and part in __________.

Fish are held for the first few years, released, and then harvested when they return to spawn.

Fig. 12-20, p. 296

Trade-Offs

Aquaculture

Advantages Disadvantages

High efficiency Needs large inputs of land, feed, and water

High yield in small volume of water

Large waste output

Destroys mangrove forests and estuaries

Can reduce overharvesting of conventional fisheries Uses grain to feed

some species

Low fuel use Dense populations vulnerable to disease

Tanks too contaminated to use after about 5 years

High profits

Profits not tied to price of oil

Fig. 12-32, p. 308

Solutions

More Sustainable Aquaculture

• Use less fishmeal feed to reduce depletion of other fish

• Improve management of aquaculture wastes

• Reduce escape of aquaculture species into the wild

• Restrict location of fish farms to reduce loss of mangrove forests and estuaries

• Farm some aquaculture species in deeply submerged cages to protect them from wave action and predators and allow dilution of wastes into the ocean

• Certify sustainable forms of aquaculture

SOLUTIONS: MOVING TOWARD GLOBAL FOOD ___________

People in urban areas could ____ money by _______ more of their ______.

______ gardens provide about ___% of the world’s food supply.

Up to ____% of the world’s food is _____.

Solutions: Steps Toward More Sustainable Food Production

We can ______ food security by slowing _________ growth, sharply _______ poverty, and slowing ________ degradation of the world’s _____ and ________.