Soil Science

Question 1

Alluvial

Answer 1

Very variable profiles from gravel to silty clay and often contain rounded pebbles and silt

Question 2

Organic layer

Answer 2

The top layer of the soil that is rich in organic matter

Question 3

Organic layer

Answer 3

The top layer of the soil that is rich in organic matter

Question 4

Bagshot podsol

Answer 4

Forms on well drained acid sites under conifers and an iron pan forms

Question 5

Chalk

Answer 5

Shallow, fertile soil over chalk or limestone with a high pH

Question 6

Topsoil

Answer 6

The region of intense biological activity that’s found below the o horizon and is dark in colour because it contains the maximum amount of OM

Question 7

Brown earth

Answer 7

Brown indistinct horizons that form on well drained soil

Question 8

Gley

Answer 8

Seen in waterlogged clay and poorly drained soils where the soil turns blue-grey

Question 9

Micropores

Answer 9

Tiny pores (less than 0.2 microns)

Question 10

Mineral

Answer 10

An element with a specific and essential role for the completion of a plants life-cycle

Question 11

Soil ameliorant

Answer 11

A substance that improves the physical condition of the soil

Question 12

Nitrification

Answer 12

A process carried out by nitrifying bacteria which transfers soil ammonium into nitrates which plants can incorporate into their own tissues

Question 13

Gravitational water

Answer 13

This is the water that will drain from the soil due to gravity. Eg - water in macropores

Question 14

Saturation point

Answer 14

When all the pore spaces are filled with water

Question 15

Field capacity

Answer 15

This is the ideal amount of water in the soil for plants and occurs when the macropores are filled and the micropore and mesopores are water filled

Question 16

Macropores

Answer 16

Large pores (more than 60 microns or 0.06 mm)

Question 17

Secondary nutrients

Answer 17

Essential but needed in smaller quantities than primary nutrients. They are rarely limiting to growth sucess

Question 18

Primary nutrients

Answer 18

Nutrients required in the largest amounts. Essential for plant cell functioning. Deficiency of these nutrients contributes to reduced plant growth, health and yield

Question 19

Capillary action

Answer 19

The tendency of a liquid to rise in narrow tubes or to be drawn into small openings

Question 20

Soil moisture defecit

Answer 20

This is the water required by rain/ irrigation to raise the soil back to field capacity

Question 21

Unavailable water

Answer 21

This is the water in micropores that is unavailable to plant

Question 22

Plant available water

Answer 22

The water held in the mesopores that plants can take up

Question 23

Permanent wilting point

Answer 23

When all the water has been removed from the macro and mesopores due to drainage, plant uptake and evaporation from the soil surface

Question 24

Nitrogen cycle

Answer 24

The biogeochemical cycle by which nitrogen is converted into multiple chemical forms as it circulates among atmospheres, terrestrial and marine ecosystems

Question 25

Eluviation

Answer 25

Removal of dissolved or suspended material from a layer or layers of the soil by the movement of water when rainfall exceeds evaporation. Such loss of material in solution is often referred to as leaching and this influences soil compaction

Question 26

Fertiliser

Answer 26

Concentrated source of nutrients that makes plants grow bigger and faster

Question 27

Nitrogen assimilation

Answer 27

How plants get nitrogen

Question 28

Ammonification

Answer 28

The remains of all living things and their waste products are decomposed by microorganisms in the process of ammonification which yields ammonia and ammonium

Question 29

Irrigation

Answer 29

Watering plants to raise the soil back to field capacity and to replace the soil moisture defecit

Question 30

Antagonism

Answer 30

Overdose of certain elements can displace other nutrients

Question 31

Aggregate

Answer 31

Lumps of soil formed by natural processes

Question 32

Horizon

Answer 32

Horizontal layers visible in a profile

Question 33

Soil profiles

Answer 33

Vertical face of a soil pit

Question 34

Unstructured soil

Answer 34

Uniform pore sizes and poor permeability

Question 35

Structured soil

Answer 35

Variable pore sizes and better permeability

Question 36

Structure

Answer 36

The joining together of soil grains into aggregates and is the arrangement of soil in a profile

Question 37

Porosity

Answer 37

Total number of pores

Question 38

Soil organic matter

Answer 38

A mixture of plant and animal remains, excreta and living organisms etc, added to the soil by natural means

Question 39

Loam

Answer 39

A mixture of sand, silt and clay

Question 40

Texture

Answer 40

Used to describe the feel of a substance, based upon the smoothness or roughness of its surface

Question 41

Soil texture

Answer 41

Soil texture is determined by the size and proportions or ratio of the small individual mineral particles

Question 42

Humus

Answer 42

Well rotted organic matter

Question 43

Permeability

Answer 43

How easily air and water can travel through the soil connections

Question 44

Leaching

Answer 44

A process of extracting a substance from a solid material that is dissolved in a liquid

Question 45

Calcicoles

Answer 45

Alkaline loving plants

Question 46

Calcifuges

Answer 46

Acid loving plants

Question 47

Igneous rocks

Answer 47

Formed from molten Lava and they are mostly formed as the Earth's crust cooled. Eg: granite

Question 48

Sedimentary rocks

Answer 48

Formed in layers by weathering of other rocks and organisms. Eg: shale

Question 49

Metamorphic rocks

Answer 49

Formed either from igneous or sedimentary rocks which have changed due to excess heat and pressure. Eg: marble

Question 50

Physical weathering

Answer 50

The rocks are broken down into smaller pieces but the chemical composition of the rock remains the same. Eg: heating and cooling

Question 51

Biological weathering

Answer 51

Caused by biological agents. Eg: plants and animals

Question 52

Chemical weathering

Answer 52

Chemical means which cause permanent chemical changes. Eg: solution and oxidation

Question 53

Soil

Answer 53

Soil is the growing medium for plants and their roots as it gives them water, mineral nutrients, oxygen and support