Soil

Question 1

Humus

Answer 1

sticky, brown, insoluble residue from partially decomposed organisms

Question 2

Topsoil

Answer 2

A horizon, mineral particles mixed with organic material, under surface litter

Question 3

Subsoil

Answer 3

B horizon, accumulated clays and nutrients, sometimes develops hardpan layer

Question 4

Sheet erosion

Answer 4

thin layer taken off land surface

Question 5

Rill erosion

Answer 5

little rivulets of running water cut small channels in soil

Question 6

Gully erosion

Answer 6

bigger channels of water that erode

Question 7

Waterlogging

Answer 7

soil saturated with water, kills plants from lack of oxygen

Question 8

Salinization

Answer 8

mineral salts accumulate in soil, saline irrigation

Question 9

Soil fertility

Answer 9

capacity to supply nutrients (nitrogen, phosphorus, potassium) for plant growth

Question 10

Soil porosity/infiltration

Answer 10

pore spaces filled with water=saturated, otherwise it is unsaturated

Question 11

Infiltration

Answer 11

water through soil

Question 12

Soil porosity

Answer 12

space between pores

Question 13

Plasticity

Answer 13

high- soil likely to have excessively expand and contract on wetting and drying

Question 14

Strength

Answer 14

ability of a soil to resist deformation

Question 15

Cohesion

Answer 15

measure of the ability of soil particles to stick together

Question 16

Friction

Answer 16

high in sand, strength of forcing particles together

Question 17

Sensitivity

Answer 17

changes in soil strength resulting from disturbances such as vibrations or excavations

Question 18

Compressibility

Answer 18

tendency to consolidate, decrease in volume, coarse- low comp

Question 19

Erodibility

Answer 19

ease with which soil materials are removed by wind or water

Question 20

Permeability

Answer 20

ease with which water moves through a material

Question 21

Corrosion

Answer 21

slow weathering or chemical decomposition that proceeds from surface into ground

Question 22

Ease of excavation

Answer 22

procedures required to remove soil during construction

Question 23

Shrink-swell potential

Answer 23

tendency of soil to gain or lose water