soil ecology (lecture 2)

7/26/2019 Soil Ecology (Lecture 2)

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Soil Ecology Takuya Marumoto Ph.D.

S o i l E c o l o

g y - L e c t u r e N o . 2 -

1

[Lecture No.2]. Role of microbe on the nutrient circulation in soil

1 Nitrogen circulation in atmosphere and soil (F-7)

2 Degradation process of organic matter (plant residence,

carcass… etc.) in soil1) Degradation process of organic matter by microfauna and microbe in soil

(F-8)

2) Changes in micro flora during the degradation process of plant residue in soil

(F-9)

3) Relationship between C/N ratio of plant residue and mineralization rate of

organic nitrogen in plant (F-10)

3 Nutrient in microbial biomass1) Amount of nutrient in microbial biomass (T-2)

2) Changes in microbial biomass and mineralized nitrogen after the drastic

change for soil environment (F-11)



S o i l E c o l o

g y - L e c t u r e N o . 2 -

2

1

Nitrogen circulation in atmosphere and soil

R a i n f a l l

D e n i t r i f i c a t i o n

Fig.7 Nitrogen circulation in atmosphere and soil




carcass… etc.) in soil

Fig.8 Degradation process of organic matter by microfauna and microbe in soil

S o i l E c o l o g y - L e c t u r e N o . 2 -

3

Plant residue and

carcass of fauna, insect

Some Level of

microbial biomass (Amount of biomass:

Stock of nutrients)

Degradation bymicrofauna and microbe

Mineralization toNH4, CO2, H2O etc.(Release of nutrients

into soil)

Multiplication of microbe

(Temporal stock of nutrients)

Change of generation,

Metabolism(Death of microbe and

new microbe generation)



Fig.9 Changes in microflora during the degradation process of plant residue in soil


4


carcass… etc.) in soil

Sugar CelluloseLignin

S

L

L

S

Sugar degradation ( Bacteria, Fungi )Cellulose degradation ( Bacteria, Fungi )

Lignin decomposition ( Mushroom )

D e g r a d a t i o n

N o . M

i c r o b e



2 Effects of plants, small animals and microbe on soil formation

Fig.10 Relationship between C/N ratio of plant residue and mineralization

rate of organic nitrogen in plant (30℃, 70days under upland condition)


5

M i n e r a l i z a t i o n r a t e o f o r g .

N ( % )

C/N ratio



3 Nutrient in microbial biomass

Tab.2 Amount of nutrient in microbial biomass of upland soil


6

Bacteria

Fungi

Total

Nutrientamountper 140Kgdry microbe*

*140Kg of dry microbe is average value in 10a of upland soil.

Each nutrient amount per 140Kg dry microbe is equal to the application amount of each

nutrient as fertilizer to common crop per year

(kg)



3 Nutrient in microbial biomass


7

Death

Mineralized nitrogen

Amount of biomass

A m

o u n t o f b i o m a s s

a n d m i n e r a l i z e d N

Environment change

Drying - Wetting

Freezing - Melting

Rising soil temperature

Aggregate crush

2~4 weeks

Fig.11 Change in microbial biomass and mineralized nitrogen after the

drastic change for soil environment

soil ecology (lecture 2)

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