SOIL PROPERTIES

Question 1

PHYSICAL PROPERTIES OF SOIL

Answer 1

1) texture
2) structure
3) soil depth
4) topography

Question 2

TEXTURAL OF LOAM SOIL

Answer 2

1) 45% sand
2) 35% silt
3) 20% loam

Question 3

SOIL STRUCTURE

Answer 3

grouping of soil particles into larger aggregates

Question 4

FACTOR RESULTING TO DECREASED AGGREGATE STABILITY

Answer 4

tillage

Question 5

INDICATOR OF STABLE AGGREGATES

Answer 5

rapid exchange of air and water with plant roots

Question 6

SOIL DEPTH

Answer 6

thickness of soil material providing structural support, nutrients and water

Question 7

SOIL’S PERMEABILITY

Answer 7

measure of the ability of air and water to move through a soil

Question 8

FACTORS INFLUENCING SOIL PERMEABILITY

Answer 8

1) soil size
2) soil shape
3) continuity of pore spaces
4) soil bulk density
5) soil structure
6) soil texture

Question 9

FACTORS AFFECTING INFILTRATION RATE

Answer 9

1) permeability of surface soil
2) moisture content of soil
3) surface conditions (roughness, tillage, plant residue, slope)
4) plant cover

Question 10

TOPOGRAPHY

Answer 10

1) physical configuration of soil surface
2) determines if field can be irrigated

Question 11

RELIEF

Answer 11

1) component of topography
2) difference in height between the hills and depressions in the field

Question 12

CHEMICAL PROPERTIES OF SOIL

Answer 12

1) pH
2) salinity (EC)
3) cation exchange capacity (CEC)
4) organic matter
5) C:N ratio

Question 13

TOXIC MINERAL IN LOW PH SOILS

Answer 13

aluminum

Question 14

MATERIALS INCREASING SOIL PH

Answer 14

1) lime (calcium carbonate/dolomitic lime)
2) wood ash
=> source of K, Ca, Mg

Question 15

MATERIALS DECREASING SOIL PH

Answer 15

1) elemental sulfur
2) ammonium and ammonium-forming N fertilizers

Question 16

INFLUENCE OF SOM IN PHYSICAL PROPERTIES OF SOIL

Answer 16

1) soil structure stability
2) improved water holding capacity
3) low bulk density
4) dark color altering thermal properties

Question 17

INFLUENCE OF SOM IN CHEMICAL PROPERTIES OF SOIL

Answer 17

1) high CEC
2) natural pH buffer
3) holds metals

Question 18

INFLUENCE OF SOM IN BIOLOGICAL PROPERTIES OF SOIL

Answer 18

1) energy for soil organisms
2) increase microbial populations
3) source and sink of nutrients
4) ecosystem resilience
5) influence soil enzymes

Question 19

DRIVING FORCE FOR NUTRIENT RELEASE TO PLANTS

Answer 19

microorganism (1-4% from SOM per year)

Question 20

CONTRIBUTES 60-80% OF SOIL METABOLISM

Answer 20

microflora

Question 21

SOIL MICROORGANISMS IN ONE GRAM OF TOP SOIL

Answer 21

1) 1 billion bacteria
2) 100 million actinomycetes
3) 1 million fungi
4) 100 nematode

Question 22

IMPORTANCE OF SOIL MICROORGANISMS

Answer 22

1) cycling of C, N, other nutrients
2) enhance soil structure
3) decompose organic materials
4) maintain soil quality
5) increase aeration and penetrability in soil
6) disease transmission and control

Question 23

RHIZOSPHERE

Answer 23

soil zone surrounding plant roots which was chemically and biologically influenced by the roots

Question 24

SOIL FAUNA

Answer 24

1) macrofauna (mice, moles, earthworms)
2) mesofauna (nematodes, arthropods, mollusks)
3) microfauna (protozoa)

Question 25

IMPORTANCE OF SOIL FAUNA

Answer 25

1) mixing and redistribution of OM
2) enhance soil physical properties
3) neutralize soil pH
4) increase availability of nutrients
5) stimulate microbial population
6) reduce harmful nematodes

Question 26

BACTERIA

Answer 26

1) diverse metabolism
2) optimal growth at pH 6-8
3) examples (nitrosomonas, nitrobacter)