Introduction

Question 1

Globale Bodenverluste

2 punkte

Answer 1

• 30% der landwirtschaftlich nützlichen bodens in den letzten 40 jahren verloren
• ca. 10 millionen hektar pro jahr

Question 2

How many individuals are in a handful of soil?

Answer 2

more than the total number of human beings that have ever existed

Question 3

how much of the total surface area is covered by microbes?

Answer 3

1x10^-5%

because of the inherantly large surface area of soil

Question 4

What are all microbes and what do they rely on?

Answer 4

• aquatic

- thin microfilms of water

Question 5

What is stored in soil more than any other place on earth?

Answer 5

Carbon

Question 6

Soil acts as an environmental scrubber for what?

Answer 6

harmful chemicals and organisms. Stps them from entering waterways or the atmosphere

Question 7

What is plant soil feedback?

Answer 7

A conceptual framework to study the interaction of soil with plants

Question 8

plant soil feedback is a two step process

Answer 8

the presence of plants alters soil conditions:

• physical
• (bio)-chemical
• biological

soil conditions affect plant growth and fitness

Question 9

plant soil feedback as a more specific term

Answer 9

refers to direct and indirect feedback mediated by neighboring plants (net pairwise feedback)

Question 10

types of feedback

Answer 10

positive and negative

feedback can be negative even if effect on plant from soil community is positive) (bever 2002???

Question 11

When does feedback occur?

Answer 11

when the four interaction coefficients are not

equal, i.e. when there are species-specific effects.

Question 12

direct pathways

Answer 12

pathogens, mycorrhizia, root feeding fauna

Question 13

indirect pathways

Answer 13

detritus food web