Soil Physical Properties Chapter 4

Question 1

What is soil texture

Answer 1

Size distribution of mineral particles

Question 2

Four soil size classifications

Answer 2

Coarse fragments>2 mm
Sands 2-.05
Silts 0.02-0.002
Clays <0.002

Question 3

How to determine soil texture

Answer 3

1. Sieving
2. Sedimentation rate(hydrometer)
3. Pipette methods

Question 4

What is bulk density

Answer 4

Dry mass of soil total volume
With pore space
Low bd has lots of pore space
High SOM can decrease Bd

Question 5

What is particle density

Answer 5

Density of soil solids
Without pore space
High som may result in lower PD

Question 6

What is greying

Answer 6

Low chroma soil

Question 7

Moted

Answer 7

Spots of one color in a overall different colored soil

Question 8

Hue
Value
Chroma

Answer 8

Hue- basic color spectral
Value- intensity of hue
Chroma- amount of purity in grey color

Question 9

Granular structure

Answer 9

Less than 0.5 cm

Commonly found in horizons with roots

Question 10

Blocky

Answer 10

1.5-5 cm
Angular/ subangular
Common in b horizons or humid regions

Question 11

Prism like

Columnar

Answer 11

Prism like- vertical axis greater than horizon

Columnar- vertical columns with round tips , salt caps

Question 12

Different soil structure grades

Answer 12

1. Structures- no discrete units observable
2. Weak- units barley observable
3. Moderate- units are well formed and evident
4. strong- units are distinct in place and separate cleanly

Question 13

Matric potential

Answer 13

High= dry
Low = moist

Question 14

Gravitational potential

Answer 14

High elevation and wet- high

Dry and low revelation-low

Question 15

Osmotic potential

Answer 15

High- alkaline/ saltier conditions/ high fertilizer

Low-leather/acidic/low fertilizers