How human activities affect soil fertility

Question 1

what is soil?

Answer 1

loose surface material that covers most land

Question 2

what is a fertile soil

Answer 2

a soil that has the nutrients to sustain plant growth and provide plant habitat that results in sustained and consistent yield

Question 3

what factors can affect soil fertility?

Answer 3

Ability to hold water
Nutrients and minerals
Good air content
relatively neutral pH
Dead organic matter
Soil depth
High levels of soil biota
soil structure
soil texture

Question 4

what is soil texture

Answer 4

the characteristics of a soil based on the proportion of the mineral particles that are sand silt and clay

Question 5

what are the sizes of the soil mineral types (big to small)

Answer 5

Sand
Silt
clay

Question 6

what is the pore size of sand

Answer 6

macro

Question 7

what is the pore size of silt

Answer 7

medium- (meso)

Question 8

what is the pore size of clay

Answer 8

micro

Question 9

what is soil structure

Answer 9

how the particles are arranged within the soil

Question 10

what is the structure of sandy soils

Answer 10

rounded grains that don’t lock together so the sandy soils drain more freely

Question 11

what is the structure of clay soils

Answer 11

‘platy’ particles and as they have long flat sides the clay ‘locks’ preventing good drainage

Question 12

why is soils ability to hold water important

Answer 12

water is necessary for all animals and invertebrates
water is needed for the process of photosynthesis
water is also how plants absorb nutrients in ionic form

Question 13

what is the problem with water logged soil

Answer 13

prevents air from reaching the plants and organisms creating an anaerobic environment and a less fertile soil

Question 14

what are some macro nutrients? (main 3)

Answer 14

nitrogen
potassium
phosphorus

Question 15

what are some micro nutrients

Answer 15

copper
iron
magnesium
manganese

Question 16

why is it important that heavy metals are not absorbed by soils?

Answer 16

as they are toxic they would harm plant and animal life reducing soil fertility and the overall biodiversity of the area that is contaminted

Question 17

why is good air content needed in soil?

Answer 17

important for decomposition which breaks down waste into nutrients

Question 18

why is a neutral pH needed? (soil fertility)

Answer 18

acidic conditions cause damage to plant membranes and can leach nutrients out of the soil

Question 19

what is the best pH range

Answer 19

5.5-7

Question 20

what is the problem with alkaline conditions

Answer 20

macronutrients become insoluble making it difficult for plants to absorb them

Question 21

why is dead organic matter important? (soil fertility)

Answer 21

DOM releases nutrients when decomposed
leaf litter and other matter increases the soils ability to hold water

Question 22

why is soil depth important

Answer 22

deeper soils hold water for longer and dry out less rapidly don’t get water logged as easily allow plants enough root space needed for growth and stability

Question 23

What are living organisms found in soil called

Answer 23

Soil biota

Question 24

What are soil biota important

Answer 24

They process DOM and convert it into nutrients and aerate the soil

Question 25

What are mycorrhizal fungi

Answer 25

Part of a symbiotic relationship with plant roots important for the absorption of phosphate get glucose in return

Question 26

What are decomposes? (Generally)

Answer 26

Broad category that includes fungi and bacteria

Question 27

How do decomposers decompose

Answer 27

They release enzymes that digest the DOM Require detritivores to break up the DOM to make it easily digestible

Question 28

What are detritivores? (species examples)

Answer 28

Insects and invertebrates such as worms, millipedes, slugs and wood lice.

Question 29

What do detritivores do?

Answer 29

Break up larger DOM into small pieces and release the nutrients into the soil

Question 30

What is the double benefit of worms?

Answer 30

They create tunnels and burrows that allow air to circulate and breakdown DOM

Question 31

Why are nitrogen fixing bacteria important

Answer 31

Important in converting gaseous forms of nitrogen to ammonium ions

Question 32

Why are nitrifying bacteria important?

Answer 32

Important in oxidising ammonium ions (animal waste) to nitrate ions which are important or plant growth

Question 33

How do humans aerate the soil

Answer 33

Done by ploughing and putting in drainage Making conditions favourable for worms

Question 34

Why is aeration important?(bacteria)

Answer 34

The soil is more aerobic which allows nitrogen fixing bacteria to exist and convert gaseous nitrogen into ammonium ions helps add nitrogen needed for growth into the soil

Question 35

Why is aerobic soil important for decomposers

Answer 35

Decomposers do not usually tolerate anoxic or anaerobic conditions

Question 36

What are the three ways a farmer can add nutrients to the soil?

Answer 36

Add organic matter Add inorganic nutrients Increase the rate of nitrogen fixing bacteria

Question 37

What is adding organic matter to the soil

Answer 37

This means adding manure or animal waste products to the soil

Question 38

What is adding inorganic material to the soil?

Answer 38

Adding artificial (man made) pellets of nitrogen, phosphorus etc

Question 39

How can farmers help to increase the rate of nitrogen fixing bacteria?

Answer 39

Planting legumes (peas and beans) which naturally add nitrogen rather than taking it away

Question 40

What happens to soil fertility on land which is farmed?

Answer 40

Soil becomes infertile overtime and looses structure and ability to hold nutrients because farming degrades soil as soil erosion is increased

Question 41

What is irrigation?

Answer 41

This is the addition of water to the soil to help plants grow

Question 42

Why is irrigation important?

Answer 42

Plants still need water for photosynthesis even if in nutritious soil Water carries the dissolved nutrients in ions the plants take the ions up through their roots without water the nutrients couldn’t be picked up

Question 43

What is bulk density

Answer 43

The weight of a soil in a given volume

Question 44

What amount of bulk density restricts root growth

Answer 44

1.6g/cm*3

Question 45

What soils are more prone to high bulk density

Answer 45

Sandy soils as they are more easily compacted

Question 46

What causes high bulk density

Answer 46

Heavy machinery or trampling by livestock like cattle

Question 47

What happens to soil pH over time

Answer 47

Can become more acidic

Question 48

What can increase soil acidity

Answer 48

When plant material is removed alkalinity is removed When grain pasture and animal products are harvested the soil is left more acidic

Question 49

How can soil acidity be reduced

Answer 49

Adding lime or chalk

Question 50

What is the structure of a silty soil?

Answer 50

granular material of a size between sand and clay and composed mostly of broken grains of quartz