Final Exam

Question 1

nitrification

Answer 1

the conversion from NH3 to NO3- by bacteria

Question 2

nitrogen fixation

Answer 2

the conversion of nitrogen from N2 to N3

Question 3

nitrogen cycle

Answer 3

cycle that transforms nitrogen and nitrogen-containing compounts

Question 4

rhizobacteria

Answer 4

free living bacteria that function in the rhizosphere and can go in and out of roots

Question 5

rhizosphere

Answer 5

the layer of soil bound to the plant’s roots, with a high level of microbial activity due to nutrients secreted by the roots

Question 6

haustorial roots

Answer 6

roots of parasitic plants that absorb water and nutrients from other plants

Question 7

macronutrients

Answer 7

the essential nutrients, needed by plants in large amounts (carbon, oxygen, hydrogen, nitrogen, phosphorus, potassium, sulfur, calcium, and magnesium)

Question 8

fertilization

Answer 8

the process of replacing mineral nutrients that have been lost from the soil

Question 9

salinization

Answer 9

concentration of salts in soil as water evaporates

Question 10

cation exchange

Answer 10

when cations are displaced from soil particles by other cations; these are then loose in the soil and can be taken up by plants

Question 11

sand

Answer 11

largest soil particle

Question 12

silt

Answer 12

medium soil particle

Question 13

clay

Answer 13

smallest soil particle

Question 14

horizon

Answer 14

layer of soil

Question 15

topsoil

Answer 15

the upper horizon of soil

Question 16

soil

Answer 16

an ecosystem, with the top layers providing nutrients and water to plants