Biology topic No. 5: SOIL ECOLOGY the general patterns · ie., soil moisture and soil nutrient content plant is uptake directly influenced by (2) measurable within years, via penetration

Tento projekt je spolufinancován Evropským sociálním fondem a Státním rozpočtem ČR InoBio

–

CZ.1.07/2.2.00/28.0018

SoilSoil Biology Biology ‐‐ topictopic No. 5:No. 5:

SOIL ECOLOGY SOIL ECOLOGY ‐‐ thethe

generalgeneral

patternspatterns,,andand

thethe

particularparticularpatternspatterns

Tento projekt je spolufinancován Evropským sociálním fondem a Státním rozpočtem ČR InoBio – CZ.1.07/2.2.00/28.0018

SOIL ECOLOGY SOIL ECOLOGY isis

anan

appliedapplied

scientificscientific disciplinediscipline

dealingdealing

withwith

livingliving

componentscomponents

ofof

soilsoil, , theirtheir

activitiesactivities

andand

THEIR THEIR INTERRELATIONSHIPSINTERRELATIONSHIPS

Soil Ecology

Soil Science

Microbiology

Zoology

Soil Biology

Biochemistry

Plant Physiology

Environmental Science


In general,

irrespectively

of

The

First

Law

of

Thermodynamics,

i) the

energy

in soil

is

degradated

from

chemical

energy to heat

‐

which

is

not recycled,

ii) ultimately, nutrients

are excreted

by organisms

(as a whole) ‐

and, they

are recycled

via plant

root

uptake.


(ultimately,

net

immobilisation

has to be

zero...

microbial

dead

cells

and

humic substances are decomposed

as well!)


Notes


Which

ecological

factors

favour

soil

biological

activity?

There

are five

the

essential

ones:oxygen availability (when an excess of water can result in O2‐

limitations; obligate aerobes vs. micro‐aerophils vs. facultative anaerobes vs. obligate anaerobes)

presence of water (as both i) the principal component of protoplasm, and ii) the carrier of nutrients into the living cells)

nutrients

osmotic pressuretemperature (psychrophiles vs. mesophiles vs. thermophiles).


In addition, there

are five

more ones:

1.

pH level

2.

toxicity of

the

soil3.

heavy

metals

content

in the

soil

4.

molecular

structure

5.

co‐metabolism


Notes


A.

there

are

hundreds

of

ecological

strategies

of

soil

biota, e.g. the

reaction

of

temperature

changings:

winter

‐

spring

time:

capsule

formation

enables

it

to

survive

at reduced

temperatures

and

grow

as the

temperature

increases;

B.

there

are

hundreds

of

ecological

strategies

of

plants

in terms

of

their

root

systems, e.g. the

reaction

to dry

conditions:

in

permanently

dry

soils,

plants

invest

a

larger

fraction

of

their primary

production

below‐ground

... to obtain

sufficient

water,

in

seasonally

dry

soils,

they

do

the same ...

to

survive

this season;


C. there

are hundreds

of

ecological

interrelationships

among plants

and

soil

biota, e.g. the

reaction

to infertile

soils:

on infertile

sites, plants

have

not enough

nutrients

to make

new tissues,

ie.

not

enough

nutrients

to

translate

their

photosynthetic

production

into

new

tissues

‐

thus, they

give

a great

deal

of

the

photosynthetical

products to

mycorrhizal

fungi

whose

growth

increases

the

plant

uptake

capacities

for

nutrients.


Notes


DealingDealing withwith soilsoil ecologyecology, , therethere are are threethree substantialsubstantial questionsquestions::


A. Which

way

plant

roots

influence

soil

itself?

There

are three

main

mechanisms

„working“

on very

different

time level:

(1) measurable

within

days, via uptake

of

water

and

nutrientsie., soil

moisture

and

soil

nutrient

content

is

directly

influenced

by

plant

uptake

(2) measurable

within

years, via penetration

of

soil

bodiesie., a formation

of

soil

pores

(3) measurable

within

centuries, via rate

of

parrent

material

weatheringie., the

amount

of

nutrients

bounds

in mineral

is

directly

influenced

by

biological

weathering


B. Which

way

soil

organisms

influence

soil

itself?

There

are three

main

mechanisms, as well:

(1) defragmentation

of

plant

litter

(2) consuming

of

soil

organic

matter

(3) bioturbation

C. Which

way

soil

organic

matter

influences

soil

itself?

There

are four

main

mechanisms

‐

the

four

ways

of

increase

in:

(1) a simple

storage

of

nutrients

in the litter (first of all, N + P + S; secondly, Ca, Mg and

K),

(2) a soil

structural

stability ‐

the

formation

of

soil

aggregates

(small aggregates

are formed

by inorganic

binding

agents; large

aggregates

come

from

organic

binding

agents),

(3) a water

holding capacity,

(4) exchange

capacity

(CEC in particular).


Notes

Documents

Biology topic No. 5: SOIL ECOLOGY the general patterns · ie., soil moisture and soil nutrient content plant is uptake directly influenced by (2) measurable within years, via penetration