Soil Microbes and Nutrient Cycling

Question 1

Members of the microbiota group include…

Answer 1

1. Bacteria
2. Protozoa
3. Fungi
4. Algae

Microbiota are organisms <200 um

Question 2

Mesobiotic soil organisms are?

Answer 2

1. Nematodes
2. Rotifers
3. Springtails
4. Mites

200-10000um

Question 3

Macrobiotic organisms include…

Answer 3

1. Worms
2. Slugs
3. snails
4. many insect groups

Any organism > 1cm

Big Group

Question 4

Bacteria are usually most abundant where?

Answer 4

The rhizosphere

Question 5

Per gram of soil how many unicellular, prokaryotic organisms (bacteria) can be present in 1 gram of soil?

Answer 5

Around 200,000,000

Question 6

What conditions do bacteria rapidly multiply?

Answer 6

1. 10-25 degrees
2. Correct moisture

Question 7

Fungi is the most abundant macrobiotic organism in soil by mass, how many t/ha?

Answer 7

2-5 t/ha

Question 8

Fungi grow from spores to produce a mass of thread-like tissue called ____.

These coalesce to form larger filaments called _____.

Answer 8

1. Hyphae
2. Mycelia

Question 9

A benefit to soil nutrition of fungi is…

Answer 9

1. In harsh condtions rhizomorphs and mycelial chords made of hyphae spread nutrients through soil water.

Question 10

What type of OM does fungal growth thrive upon?

Answer 10

Lignified

Question 11

What is generally the most significant type of mesobiota?

Answer 11

Nematodes

Question 12

Pros and cons of nematodes?

Answer 12

1. Pro- many types feed harmlessly on microbiota and help recycle nutrients.
2. Con- Some are real pricks and feed on living grass

Question 13

What role do earthworms play in speeding up nutrient cycling?

Answer 13

They break down OM into smaller units with larger surface area, speeding up its decomposition by fungi and bacteria.