Soil Texture & Fertility

Material that supports plant life

What is soil?

O= Organic layer= humusA= Topsoil, mixture of organic & mineralsE= Eluvial (leached) mineral horizon

B= Subsoil: accumulation of organic &/or inorganic matter

C = Parent material, un-weathered

Soil profile & horizons

How is soil created?

ClimateTopography(relief)TimeOrganismsParent material

Factors that influence soil formation

Gravitational water: water that moves through soil under the influence of gravity.

Field capacity: water held in the soil by capillary forces, available to plant

Hygroscopic water: water that is adsorbed by soil particles, unavailable to plant

Adsorbed: held in place, attached to

Vocabulary

Inorganic: Synthesized from minerals

Quick releaseShort term plant

growth

Slow releaseLong term soil

health

Fertilizers: 6 primary nutrients

Organic: from plant and animals

Excess nutrients :Human harm: methemoglobinemia (Blue Baby Syndrome)Environmental harm: eutrophication

Smaller particles have a Greater surface area: 54cm2 162cm2

Higher chemical reactivity: clay is (-) attracts (+)Nutrients: Mg+, Ca+, K+, Na+

Non-nutrients : H+Higher water holding capacity: water is polar

Soil Texture: determined by sand, silt,& clay

1 cm3 cm

Is it 33% for all separates?What soil type is

18% clay, 40% sand, 42% silt?

This point is where each separate has equal influence

How much sand is required to get its name in a class?

Last word is most important

Which soil type is the best for plant growth?

Does more clay mean more available water?

Plants can survive with 50% of FC.

Soil Texture and Soil H2O Gravitational water: water that moves through soil under the influence of gravity.

Field capacity: water held in the soil by capillary forces

Hygroscopic water: water that is adsorbed by soil particles

Getting the most out of the soilIntensive monoculture farming

Row crops, altering the landscape, weed free Physical damage:

ErosionCompaction: reduce aeration

Chemical damageSalinization

Conversion Desertification

MyakkaFine sand

Casa GrandeSandy Loam

DrummerSilty, clay loam

Houston Black Black clay

MyakkaFine sand

Casa GrandeSandy Loam

DrummerSilty, clay loam

Houston Black Black clay

What soil type would most likely need to have more fertilizer applied to it?

Which farmer will need to irrigate their crops most often?

Which farmer will most likely have to face salinization problems?

Which farmer would most likely encounter gully or sheet erosion?

Which farmer would most likely have waterlogged soil if there was a heavy rainfall?

Which farmer has the best developed “O” horizon? Which farmer would most likely have the most acidic

soil?

Review Questions