The San Juaquin Series

The San Joaquin Series consists of moderately deep to duripan, well and moderately well drained soils that formed in alluvium derived from mixed but dominantly granitic rock sources. They are on undulating low terraces with slopes of 0 to 9 percent. The mean annual precipitation is about 15 inches and the mean annual temperature is about 61 degrees F.

Soil colors: what can you infer?

1) red

2) white

3) yellow & orange

4) grey

1) red:  rich in iron

2) white: silicate matrix

3) yellow & orange: rich in iron

4) grey: rich in iron and organic matter

Soil parent material is not always derived from the underlying parent material.  In some cases, rick is covered by other geologic materials deposited by

1) ice:

2) water:

3) wind:

4) gravity:

and these deposits are called? 

1) ice: glacial till

2) water: alluvium

3) wind: loess

4) gravity: colluvium

alluvial - deposition by water

colluvial - deposition due to gravity (e.g., avalanches, mudslides, landslides)

eolian - deposition by wind

Soil Material Fractions:

1.  In a medium-textured soil what part of the soil is solid? Pore space?

2. For optimum plant growth, was is the percent air, water, organic, and mineral material?

1.  50% of soil matter is soil; 50% is pore space or voids

2.  25% air; 25% water; 5% organic; 45% mineral

Give the approximate pH for the specified soils:

1. humid

2. arid

3. range of pH in all soils

1. humid soils tend to be acidic (5-7 pH)

2. arid soils tend to be relatively basic (6.5-8.8 pH)

3. 3.2 - 10.8

Name and describe the four soil forming processes.

Additions include the adding of: organic matter from plants, water, air, and energy from the sun.
Losses include: water due to evaporation or transpiration and nutrients leaching from the soil or being taken up by plants.
Translocations include the movement of: clay, organic matter, salts, and nutrients from one layer to another.
Transformations include: the formation of clay, and the arrangement of the soil components into structural aggregates.

Stands for eluviated;

Mineral horizon characterized by the loss of silicate clay, Fe, or Al, causing a higher concentration of sand and silt particles.

O and B.

Oi: undegraded

Oe: slightly degraded

Oa: highly degraded

Bt: increased clay content;

accumulation of illuvial clay

Bg: reducing conditions known as 'gleying'

Natural sources: respiration (CO2 release => carbonic acid) and acidic exudates from roots

Anthropogenic sources: increasing SO2 & NOx deposition, and atmospheric CO2; point-sources: mining

*Rocks contain only bases and no acid precursors. Therefore, with the exception of sulfide containing rocks, soils cannot acidify as a result of atmospheric rock weathering.

1.  What is gleying?

2.  What letter is used to designate this 'subdesignation'?

1.  Gleying (also known as 'mottling') is when varying colors develop under reducing conditions, which result when the soil is saturated with water for significant periods of time; the colors are often various shades of red or rust-colored spots but sometimes can manifest as grey or blues

2. 'g' ; in the B horizon (e.g., Bg); 

What is illuvium?

Illuvium is material displaced across a soil profile from one layer to another by the action of rain water