Soil

Question 1

what is a soil?

Answer 1

a soil is vital for the effective growth of plants , which are the ‘starters’ of food chains and ecosystems

Question 2

what is a fertile soil?

Answer 2

a fertile soil is a soil that has the nutrient to sustain plant growth

Question 3

what is aeration like in sandy soil?

Answer 3

the pore spaces in well drained sandy soils are filled with air

Question 4

what is capillary action like in sandy soil?

Answer 4

capillary action = how easily water can rise to the surface
due to effective drainage there is no capillary action

Question 5

what is drainage rate like in sandy soil?

Answer 5

they have larger pore spaces so water drainage is more rapid which reduces water content but means no water logging.

Question 6

what is ease of cultivation like in sandy soil?

Answer 6

ease of cultivation = how easily plants can be grown.
because the grains do not stick together so well the soil is easier to break up for ploughing and planting the crops.

Question 7

what is nutrient retention like in sandy soil?

Answer 7

nutrient retention = how well nutrients are held in the soil
nutrients absorb poorly to rounded sand particles meaning nutrients can be washed out.

Question 8

what is root penetration like in sandy soil?

Answer 8

roots penetrate more easily as the soil is not held together as tightly

Question 9

what is thermal capacity like in sandy soil?

Answer 9

thermal capacity = how effective the soil is at maintaining a consistent temp
sandy soils warm up rapidly but also cool rapidly. They hold temperature less consistently but warm up quicker in the spring.

Question 10

what is aeration like in clay soil?

Answer 10

they have only tiny pore spaces so tend to have low aeration levels.

Question 11

what is capillary action like in clay soil?

Answer 11

capillary action = how easily water can rise to the surface
tiny pore spaces between clay particles allow water underground to rise up to the surface

Question 12

what is drainage rate like in clay soil?

Answer 12

the shape of the minerals mean poor drainage

Question 13

what is ease of cultivation like in clay soil?

Answer 13

ease of cultivation = how easily plants can be grown
the platy materials bind well, this can make it difficult to break the soil up when cultivating fields

Question 14

what is nutrient retention like in clay soil?

Answer 14

nutrient retention = how well nutrients are held in the soil
nutrients absorb readily to platy minerals holding nutrients well

Question 15

what is root penetration like in clay soil?

Answer 15

platy particles are held together by water from capillary action so plants have to work harder to put roots through

Question 16

what is thermal capacity like in clay soil?

Answer 16

thermal capacity = how effective the soil is at maintaining a constant temperature
clay has high levels of water contained so the thermal capacity is good - warming up slowly and cooling slowly, maintaining a more consistent temperature.

Question 17

what is soil texture?

Answer 17

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

Question 18

diameter of soil mineral types

Answer 18

sand == 2.0 - 0.02mm
silt == 0.02 - 0.002mm
clay == <0.002mm

Question 19

what is the soil structure of sand?

Answer 19

sandy soils have rounded grains that don’t lock together and drain more easily

Question 20

what is the soil structure of clay?

Answer 20

clay soils have platy particles and as they have a long flat slide, the clay locks preventing drainage.

Question 21

explain how aeration can affect soil fertility (human activity)

how does aeration improve the soil?

how does well aerated soil improve the plant?

Answer 21

This is done by ploughing and putting in drainage.
well aerated soils are more likely to lead to healthy plants because the soil is more aerated. This allows useful nitrogen fixing bacteria to exist and convert nitrogen to ammonium ions, this process helps add nitrogen to the soils which the plants need to grow.
decomposition is also better if the soil contains more air as the decomposers do not generally tolerate

Question 22

explain how addition of soil nutrients can affect soil fertility (human activity)

what are the three ways farmers can add nutrients to the soil?

how does farming negatively affect soil?

Answer 22

1) add organic matter- adding manure or animal waste products to soil
2)add inorganic nutrients such as artificial pellets of nitrogen, phosphorus
3)farmers can try to support soils by helping to increase the rate of nitrogen fixing bacteria - like planting legumes.

farming can degrade soil because it increases soil erosion and breaks down the soil so it loosens the structure and the ability to hold nutrients, soil may become infertile

Question 23

explain how irrigation can affect soil fertility (human activity)

what is irrigation?
how does irrigation improve fertility?

Answer 23

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

irrigation increases the fertility of soil were water is the limiting factor for growth. having sufficient water allows plant to keep their stomata open and continue gas exchange when the soil would otherwise be dry.
water also dissolves nutrients which can then be absorbed by plants in an ionic form.

Question 24

explain how soil compaction can affect soil fertility (human activity)

how does human activity affect compaction of soil and therefor soil fertility?

Answer 24

excessive use of heavy machinery or high livestock density can cause soil to be compacted. this reduces aeration and makes waterlogging more likely, especially when soil is wet.

Question 25

explain how pH can affect soil fertility (human activity)

how does soil become acidic overtime?
what does controlling pH help with?

Answer 25

soils can become acidic over time. when plant material is removed, soil acidity increases as the alkalinity is also removed. farmers can add lime or chalk to reduce acidity

controlling soil pH helps to ensure nutrients are soluble but not too easily leached.

Question 26

what are natural features that reduce erosion?
explain windbreaks…

Answer 26

wind breaks, vegetation acts as a natural windbreak slowing down wind and acting as a barrier to erosion.

Question 27

what are natural features that reduce erosion?
explain blankets…

Answer 27

leaves from vegetation fall and create a “blanket” preventing some degree of rain splash erosion

Question 28

what are natural features that reduce erosion?
explain how surface run off is reduced…

Answer 28

plants also increase infiltration, encouraging droplets into the soil rather than over the surface - this reduce surface run off

Question 29

what are natural features that reduce erosion?
explain how plant roots reduce erosion…

Answer 29

plant roots help bind the soil together, slowing down erosion

Question 30

what are natural features that reduce erosion?
explain how leaf litter reduces erosion…

Answer 30

leaf litter will fall on the floor and decompose into the soil providing nutrients

Question 31

features of a fertile soil:
what are the 9 features of a fertile soil

Answer 31

-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 32

features of a fertile soil:
ability to hold water

why is water necessary?
what is water used for?
why can water be a bad thing?

Answer 32

water is necessary for all animals including invertebrates
plats also need water for survival as a part of photosynthesis, water s the only way plants absorb nutrients as they are dissolved in ionic form

soils that become water logged are no good as it prevents air reaching the plants and organisms

Question 33

features of a fertile soil:
nutrients and minerals

name and example of the two types of nutrients in soil?
how is it ensured that plants don’t absorb heavy metals?

Answer 33

fertile soil contains a range of macronutrients and micronutrients.
macronutrients= nitrogen, potassium, phosphorus. usually found in a dissolved ionic form that plants absorb through absorption of water
micronutrients= copper, iron, magnesium and manganese

a fertile soil has a soil structure that means dangerous heavy metals are not taken up by plants, as they are absorbed mineral particles such as clay, this prevents them from dissolving into the water where they would harm plant and animal life.

Question 34

features of a fertile soil:
good air content

why is air important for soil?

Answer 34

plants and animals usually need access to oxygen. A lot of the processes that take place in soil (such as decomposition) , helps to break down waste into nutrients this requires aerobic conditions. soils that are aerated are usually more fertile.

Question 35

features of a fertile soil:
relatively neutral pH

why are acidic conditions bad for plants?
what is the best pH level for plants?
why is alkaline conditions bad for plants?

Answer 35

acidic conditions are not usually tolerated by animals or invertebrates. Acidic conditions also cause damage to the membranes and can leach nutrients out of the soil.
Best pH range for plants is 5.5-7.0
too alkaline means that some of the macronutrients such as phosphates become insoluble, making it difficult for plants to absorb them.

Question 36

features of a fertile soil:
dead organic matter

what are two benefits of DOM?

Answer 36

the breakdown of leaf litter and other natural remains break down, as they decompose they release nutrients into the surrounding soil, this increases the macronutrients available.
DOM increases the ability to hold water

Question 37

features of a fertile soil:
soil depth

3 benefits of deep soils

Answer 37

deeper soils hold water for longer as they tend to dry out less rapidly
they don’t water log as easily
important in ensuring plants have the root space required for growth and stability

Question 38

features of a fertile soil:
high levels of soil biota

what is soil biota?
what is it essential for?

Answer 38

living organisms that exist in the soil are known as soil biota. they are essential for fertility as they process DOM and convert it into nutrients.

Question 39

features of a fertile soil:
high levels of soil biota

what are the 5 groups of soil biota?

Answer 39

1) MYCORRHIZAL FUNGI - part of a symbiotic relationship with plant roots they are important in the absorption of phosphorus
2) DECOMPOSERS - fungi and bacteria, they release enzymes to digest DOM. they also require detritivores to break up the DOM beforehand so its easier for them to digest
3) DETRITIVORES - insects and invertebrates (worms,millipedes,slugs,woodlice) break up larger DOM to release the nutrients into the soil.
4) BACTERIA (nitrogen fixing) - convert gas forms of nitrogen to ammonium ions)
5) BACTERIA (nitrifying) - oxidising ammonium ions to nitrate ions which are important for plant growth

Question 40

what is the universal soil loss equation (USLE)
what does each part of it stand for?

Answer 40

A= R x K x LS x C x P
A = average annual soil loss
R= rainfall
K= soil erodibility factor
LS= slope length
C= cropping practice
P= support practice factor

Question 41

human activity that causes soil erosion to be damaged:
how does removal of vegetation affect soil erosion?

Answer 41

removing vegetation leaves the soil exposed to the process of wind and water erosion.
there is no longer roots to bind the soil to create humus that holds the soil together

Question 42

human activity that causes soil erosion to be damaged:
how does ploughing/tilling affect soil erosion?

Answer 42

ploughing breaks up the soil. therefor breaking the soil structure so the soil particles are no longer in larger clumps so therefore more vulnerable to erosion

Question 43

human activity that causes soil erosion to be damaged:
how does overgrazing affect soil erosion?

Answer 43

allowing cattle to overgraze can mean that nothing is left to cover the soil if it has all been eaten. the soil therefor has no protection from wind and water erosion.
animals trampling can also cause erosion

Question 44

human activity that causes soil erosion to be damaged:
how does loss of soil biota affect soil erosion?