Soil Flashcards
1
Q
What are Edaphic Factors?
A
- abiotic factors relating to the physical or chemical composition of the soil found in a particular area
2
Q
What is Soil?
A
- the material found on the surface of the earth that is a complex mixture of minerals, water, air, organic materials and organisms that are decaying remains of once living things.
3
Q
Why is Soil important?
A
- soil is important because they are useful for plants.
- plants need soil for anchorage, nutrients like potassium, nitrates and salts, water and air which is also important to the organisms living in the soil like earthworms.
4
Q
Why are organisms important to soil?
A
- they are important because they create burrows in the soil that help with the physical organization of the soil and there droppings also help to fertilize the soil.
5
Q
How is soil formed?
A
- soil is made from rock
- rocks are weathered by environmental elements such as wind, water, freezing and thawing and broken down into smaller particles called rock waste
- rock waste then becomes colonised by lichens, mosses and various types of plants
- these plants and animals die and decay and their remains provide organic material for the mineral composition of the soil
- because colonisation takes a long time, good soil takes thousands of years to form
6
Q
What are the different types of soil?
A
- clay soil
- sandy soil
- loam soil
7
Q
What are the properties of Clay Soil?
A
- very small particles
- poor aeration because particles are tightly packed together
- good water holding capacity because of capillarity
- poor drainage because capillarity therefore gets water-logged easily
- holds alot of mineral ions because of attraction to clay particles
8
Q
What are the properties of Sandy Soil?
A
- very large particles
- good aeration because particles are loose
- poor water holding capacity because the particles are loose
- good drainage because the particles are loose
- not a lot of minerals because they are drained out with water
9
Q
What are the properties of Loam Soil?
A
- a mixture of both sand and clay particles
- moderate aeration
- moderate water holding capacity
- moderate drainage
- contains an adequate amount of mineral ions and nutrients
10
Q
What are the three main layers of soil?
A
- topsoil
- subsoil
- bedrock
11
Q
What is a Soil Profile?
A
- a soil profile is a vertical cross-section of soil that allows you to see the different constituents that make up the soil.
12
Q
How is a Soil Profile formed?
A
- when soil is added to glass jar and water is poured, when allowed to sit for a while, the soil will settle into different layers
- this happens because of particle size and density
- the bigger particles are more dense than the smaller particles so they will settle to the bottom while the smaller ones being less dense will settle towards the top.
13
Q
What is Topsoil?
A
- the uppermost layer of soil
- it contains the highest concentration of organic material and microorganisms
14
Q
What are the six main constituents of topsoil?
A
- living organisms
- water
- air
- nutrient ions
- mineral particles
- humus
15
Q
What is Humus?
A
- dark, sticky material formed from the breakdown of dead plants and animals and other organic matter such as faeces
- the organic matter is broken down by bacteria, fungi and organisms like earthworms
16
Q
Why is Humus useful?
A
- it contains minerals
- minerals are held together because of the sticky composition
- it improves crumb structure
- it formas clay humus complexes that improve soil stability
- it has a dark colour which gives it warming capabilities
- can make the soil more acidic
- it is food for organisms like earthworms
17
Q
What is Bacteria’s function in soil?
A
- they help to breakdown organic matter into a dark, sticky material called humus.
18
Q
Why are Earthworms important to soil?
A
- they help to make burrows in the soil which help with aeration and drainage
- they eat the soil and mix it with mucus in their guts then excrete the waste which helps to improve soil crumb sructure
- they also add humus to the soil by pulling dead leaves into the soil, excreting waste and organic material when they die
-
19
Q
Why is water important to the soil?
A
- for the growth of plants and organisms like fungi and bacteria
- it is the world’s best solvent
- they produce salts readily with chemicals in the parent and they are take up to the plants by their roots
20
Q
What are extreme conditions that come with water?
A
Flooding - when all the available space in the soil gets taken up by water so it rises above the topsoil
Water-logging -
21
Q
Why is air important to soil?
A
- needed for growth of plants, bacteria and earthworms
- needed for plants, micro and macro organisms to respire
22
Q
What are mineral nutrients?
A
- elements or compounds that are either bound chemically to clay particles or dissolved in water.
23
Q
Why do plants need mineral nutrients?
A
- for growth and repair of their cells
- for certain chemical reactions to take place
They obtain their nutrients through diffusion or active transport.
24
Q
Soil Temperature
A
- water is slow to attract heat which means that wetter soils are harder to heat up than dry soils.
25
Q
Soil pH
A
- soil pH is the meaure of acidity in the soil
- plants need a certain pH to grow well and organisms like earthworms and bacteria thrive in neutral or near-neutral environments
- the pH in soils range from 4-9
