carbon cycle in terrestrial environment -...

Carbon cycle in terrestrial environment

Carbon cycle in terrestrial environment

Document extocument obtenu sur le site http://agroecologie.cirad.fr

OutlineOutline Soil organic carbon (SOC) pool’s – active and

stable fraction – concepts and formation of the humic substances

Microbial biomass – activity, functionality and interaction with cropping system

Characteristics and functionality of the SOC pool’s

Field practice in the school farm – Soil profile assessment, Soil sampling practice for no-tillage and cropping system’s (disturbed and undisturbed samples – cores and clods and crop residues); Detailed discussion about soil sampling methods for no-tillage soils


Soil componentsDocument extocument obtenu sur le site http://agroecologie.cirad.fr

Input of 1.0 ton of crop residues

0.736 ton

25° SL

Soil organic matter pool’s

Live organism

0.044

Stable (0.22 ton)

Humic Substances

No humic substances

0.06 0.16

COCO22

Source: Sá et al. 2001; 2007

Distribution of the decomposition products of the crop residues in the SOM pools

Cerrado Sinop-MT

0.863 14° SL Cerrado

(PvLt) 0.847 16° SL


Soil organic matter

Non humic substances

Humic substances

Extracted with NaOH

Live organisms Biomass

Identifiable dead tissue Debris

No live, No tissue Humus

Precipitate Soluble

Humic acidDark brown to black,

high molecular weight > 300,000

Fulvic acid Yellow to red, low molecular weight12,000-50,000

Extracted with acid (pH 1)

Humin High condensed,

Humin-clay complex

Insoluble organic substances

Decomposition active zone

Aggregation active zone

Zone of aggregation in

layers

General pool’s of SOMGeneral pool’s of SOMDocument extocument obtenu sur le site http://agroecologie.cirad.fr

Litter / Crop Residues

DefinitionDefinitionMacro-organic matter

(Ex. crop residues placed on the soil surface)


Definition (Gregorich & Jensen, 1995)

Plants and animals tissue not completely decomposed and the partial decomposition products that happen inside of the soil and that can be isolated for density using dense liquids or wet/dry sieve

Stable SOM

CO2CO2

Plant residues

SOM Light fraction

Photo: Dr. Christian Feller, 1994 (210-2000 m)

Light fraction

Humification increasingHumification increasing

CO2CO2


Root exudates




layers


Relative size of the soil organisms



Zone of aggregation in layers


1. simple exudates that leak of the cells of the plant for the soil.

2. secretions, simple combinations thrown by metabolic processes.

3. mucilage of the plant, more complex organic combinations than they arise in root cells or of bacterial degradation.

4. Mucigel, a gelatinous layer composed of mucilages and of soil particles mixed.

5. Lyzed, composed liberated by digestion of cells through bacteria.

Portion of the soil in the neighborhood of the roots where the abundance and the composition of the microbial population are influenced by the presence of those roots.

Rizosphere:

Rizodeposition: Significant amounts of organic components are exudates, secreted or thrown in the surface of young roots.


Exu

date

sEx

uda

tes

SoilSoil RootRoot


RizodepositionRizodeposition

Washed rootsWashed roots Roots + soilRoots + soil


Rizodeposition rate of some crops

Species Rizodeposition rate

Type of Rizodeposite

Reference

Corn Glucose Frutose Sucrose maltose amino acid N- Compounds

8,76 mg g-1 root day-1

0,88 mg g-1 root day-11,30 mg g-1 root day-12,04 mg g-1 root day-10,80 g g-1 root h-1

10-680 g-1 root day-1

Shonwitz & Ziegler, 1982Shonwitz & Ziegler, 1982Shonwitz & Ziegler, 1982Shonwitz & Ziegler, 1982Jones & Darrah, 1993Matsumoto et al., 1979

Wheat Soluble C -polysaccharides

66-243 mg g-1 root day-1 Prikryl & Vancura, 1980

Legum. Exudates (amino-Compounds)

250 mg g-1 root (3-4 s) Whips & Linch, 1985

Grass Soluble Exudates, polysaccharides

500 mg g-1 root (3-4 s) Whips & Linch, 1985


Organic acid Conc. Soil Solution (x 105 M)

Presence in the nature

Acetic 265-570 microbial Metabolic –accumulates in case of anaerobic microbial respiration. Commonly found in roots exudates of several grassy and cover crops. It is volatile, it can be adsorption for the clay.

Cítric 1,4 Identified in roots exudates. Presence in high concentrations in leaves and fruits. Produced by the soil fungus.

Formic 250-435 Produced by bacteria in the ryzosphere. It has been isolated of exudates of corn roots. IT IS VOLATILE.

Malic,Tartaric 100-400 Excreted by the roots of several cereals and solanacea.

Oxalic 6,2 Produced during the “Lysed” of microbial cells. Commonly present in roots exudates of cereals. NO VOLATILE.

Fonte: Huang & Volante, 1986, pg. 168.

Types, origin and concentration of organic acids founded in the nature and in the soil solution


7-12 Mg ha-1 ano-1

Tropical forest

14-18 Mg ha-1 ano-1

Pasture

1-15 Mg.ha-1.ano-1

Annual Crop

Soil Soil Microbial Microbial biomassbiomass

Soil solutionSoil solution

NH4+ NO3

-Ca2+

K+

PO3-

Mg2+

AtmosphereAtmosphere

COCO22

N2O

CH4NOx

Soil Soil Organic Organic MatterMatter Humus

Amounts of litter or crop residues produced annuallyDocument extocument obtenu sur le site http://agroecologie.cirad.fr




layers


Root system play the first step to reorganize the new aggregates


BRQ – 2 yr BRQ – 1 yr Cotton/African millet

Cotton/Brachiaria 2 years

Cotton/African millet - 2 years

LEM - Neossolo (11% of Clay)Document extocument obtenu sur le site http://agroecologie.cirad.fr

Tropical Forest Cerrado Pasture (Brachiaria) NT 12 years

Corn/Soybean


NT 12 yr

Sb/Corn

Pasture Brachiaria

Forest


78% of clay -Santa Rosa - RS

Native field - Grasses NT 10 yr – Soybean/wheat


Roots(Annual crops) 1,5 a 3,8 m (Pastures) 38 a 76 m

Bacterium 300.106 a 50.109

Actinomicete 100.106 a 2.109

Protozoa 100.103 a 50.106

Fungus 500.103 a 100.106

Nematodes 1.103 a 10.103

Artropodes 100 a 1.103

Earthworm 0 a 2

Amount of organism in Amount of organism in 100 to 200 g of soil100 to 200 g of soil

Relative amount of organism in a portion of soilDocument extocument obtenu sur le site http://agroecologie.cirad.fr

The importance of soil aggregation

Source: Mikha and Rice, 2004

Clay

Clay

Clay

Clay

Clay

Clay

Clay

Clay

Clay Clay

Clay

Clay


bactériasfungosnematóidesprotozoários

rotíferosácaroscolêmbolasproturas

diplurasymphyla

enchitreidachelonethiisóptera

0,001 0,01 0,1 1 10 100

MicrofaunaMicrofaunaopiliones

isópodasanfípodaschilópodasdiplópodas

oligochaetascoleópteras

araneidamoluscos

MesofaunaMesofauna MacrofaunaMacrofauna

(Source: Swift et al., 1979)

Size scale of the decomposers organismsSize scale of the decomposers organisms

(mm)


0

5

10

15

20

25

30

>2000 250-2000 53-250 <53

Aggregate size class ( )

Dry

mas

s (g

)

Control(mycorrhizal)

Mycorrhizal -suppressed

Effect of mycorrhizal suppression on aggregate distribution

(Wils

on a

nd R

ice,

200

4)


Decomposition sequence of the organic compounds

Organic Compounds Decomposition

Sugars, Starches, and simple proteins

FAST

Protein binded

Hemicellulose

Cellulose

Wax and Fatty

Phenolic compounds and lignins SLOW


Crop Residues

Types of Organic Compounds in the crop residues C/N Ratio

Polysaccharides Amines and simple protein

Wax and Fatty

Polifenols Lignins

Black Oat *** * ** ** ** 28 – 32

Rye *** * ** ** ** 34 – 42

Wheat *** * ** ** ** 34 – 42

Triticale *** * ** ** ** 34 – 40

Millet *** * ** *** ** 36 – 44

Corn *** * *** *** *** 64 – 80

Sorghum *** * *** *** *** 65 – 80

Braquiária *** * *** *** *** 55 – 60

Turnip *** ** ** * * 16 – 18

Vicia *** *** * * * 13 – 16

Lupinus *** *** ** * * 16 – 18

Soybean *** *** ** * * 13 – 16

Beans *** *** ** * * 13 – 16


Humification pathway

Microorganism transformation

Amine CompoundsSimple sugar

Polifenols

Quinones

Lignin decomposition

products

Quinones

Lignin Modified

1 23

4

Crop Residues

C Stable Adaptado de Stevenson, 1994


Nucleus of the Fulvic acidDocument extocument obtenu sur le site http://agroecologie.cirad.fr

Nucleus

Peptides Carbohydrate

Phenolic acidMetals

Schematic representation of the molecule of the Humic Acid


Schematic representation of the Humic Acid molecule

Schematic representation of the Humic Acid molecule


Humus

The stable part of the Soil Organic Matter

Humus

Non humic substances

Humic substancesFulvic acid Humic acid

Increase the molecular weight2000 > 300.00045% Increase the C content 62%48% Redution of the O2 content 30%1400 Redution of the acid change 500

Increase the polimerization degree


atom of hydrogenatom of carbonatom of oxygenatom of nitrogenatom of sulfur

Humic Substances


Plants tissue

CarbohidratesMonosaccharides: glucoseOligosacharides: maltose, SacarosePolysaccharides: cellulose, amilose, hemicellulose e

poligalaturonic acids

Cellulose :

The biochemical nature of the plants and animals organic compounds


Sugars and StarchesDocument extocument obtenu sur le site http://agroecologie.cirad.fr

Polifenols


LigninDocument extocument obtenu sur le site http://agroecologie.cirad.fr

• alifatic Alcohol : C20 H4 O5 Cl

• Ester of lengthy chain

Fatty and wax

Lipids


Some important structural groups of organic molecules

Amine

Amine

alcohol

aldeid

carboxil

Carboxilic ion

Enol

Cetone

Keto Acid

Carbonil insaturate

Anidride

Imine

Imine

Ether

Ester

Quinone

Hidroxiquinone

Peptide


No-till systemNo-till system

Integration of cultural and biological practices tends as base the crop rotation and the dry biomass production for soil mulching formation



The No-tillage base line is based on the maintenance of the soil permanent covered through the crop residues addition and the crop system


No-till system No-till system The effect of the interaction among the chemical, physical and biological attributes is more important than the isolated effect of each attribute


The mechanisms and processes changes don't repeat in the same way

“The cropping systems are dynamic”



Rearrange and structural stability, maintenance of the water and gases flows in the pores and increase the soil fertility

Restoration of the Soil Organic Matter with No-till adoption

Restoration of the Soil Organic Matter with No-till adoption

ProvideProvide


Natural vegetationNatural vegetation

Conventional Tillage

No-tillNo-till

Which are the differences among the aggregates and the soil

organic matter pool’s?


No-Tillage

Reaggregation

CR + roots

Continuous C flux

Active “Pool”Slow “Pool”Passive “Pool”

New Steady State

Contiuous porosity

Natural Vegetation

Litter + roots

Active “Pool”Slow “Pool”Passive “Pool”

Contiuous porosity

SteadyState

Aggregation

Continuous C flux

Conventional Tillage

Aeration + mix to Crop

Residue

Active MCB and high CO2 flux

Struture disrupted

InstableSOM Losses

Basic differences among of the land

use systems


No-till (22 years)

Natural Vegetation

Conventional tillage

(22 years)

POM (> 53 µm) C ton ha-1

2.461.86

3.06

0-2.5 2.5-5.0 5.0-10

5.81

3.56 3.47

0-2.5 2.5-5.0 5.0-10

3.132.39

3.64

0-2.5 2.5-5.0 5.0-10

7.53 6.62

11.34

0-2.5 2.5-5.0 5.0-10

6.76 6.50

11.69

0-2.5 2.5-5.0 5.0-10

12.8810.49

13.89

0-2.5 2.5-5.0 5.0-10

Stable OM (< 53 µm) C ton ha-1


No-till (22 years)

Natural Vegetation


(22 years)

Depth Native Field CT NT

(cm) POM HOM POM HOM POM HOM

---------------C (ton ha-1)---------------

0-2.5 3.13 7.53 2.46 6.76 5.81 12.88

2.5-5 2.39 6.62 1.86 6.80 3.56 10.49

5-10 3.64 11.34 3.06 11.69 3.47 13.89


No-till (22 years)

Natural Vegetation


(22 years)

Native Field CT NT

POM HOM POM HOM POM HOM

-----------------C (ton ha-1)-----------------

9.2 25.5 7.4 25.3 12.8 37.3

(Difference)* - 1.8 - 0.2 + 3.6 + 11.8

* Difference between Tillage - Native Field (0 to 10 cm layer)


Macroaggregate model and hierarchyMacroaggregate model and hierarchy(Tisdall & Oades, 1982)





layers


Soil temperature with (9.2 ton ha-1) and without crop residues (Brachiaria Decumbens) on the soil surface (NT - 10 years – Rio Verde – GO)

16 ° LS

Soil temperature with (9.2 ton ha-1) and without crop residues (Brachiaria Decumbens) on the soil surface (NT - 10 years – Rio Verde – GO)

16 ° LS

No Crop Residues

62.9 ºC

Crop Residues

32.6 ºC

(Two years average: 01/14/2003 and 01/13/2004 at 2pm)


Macroaggregate model and hierarchyMacroaggregate model and hierarchy(Tisdall & Oades, 1982)




Zone of aggregation in layers


A zona do solo distante de 1 a 2 mm das raízes das plantas vivas chama-se rizosfera. Esta zona éaltamente enriquecida com elementos orgânicos excretados pelas raízes.

Raízes c/ soloRaízes c/ solo

0.8 to 2.0 ton ha-1 yr-1

as a root exsudates

Phot

o: L

. Seg

uy, 2

001

(MT)

Eleusine Coracana – C4 – Tropical grassDocument extocument obtenu sur le site http://agroecologie.cirad.fr

Macroaggregate HierarchyMacroaggregate Hierarchy

(Tis

dall

& O

ades

, 198

2)


Silt-size microaggregate

Clay microstructures

Plant and fungal debris

Particulate organic matter

Microaggregates 20-90 and 90-250 �m

Mycorrhizal hyphae

Pore space; polysaccharides and otheramorphous interaggregate binding agents

Microaggregates-macroaggregates modelMicroaggregates-macroaggregates model

Adapted from Jastrow and Miller, 1997Slide from Dr. Charles Rice Presentation - Argentine

Plant root

Microaggregate <250 m

Macroaggregate >250 m

© 1999 M.Mikha


C sequestration on no-till system –Scientific approach


Hypothesis

“The macroaggregation is the main way to protect the C released from the crop residues decomposition. Stimulate the interactions among soil chemical, physical and biological attributes”


Aggregates Protection

C

No-till systemsCrop residues input

Oxidation reduction

The C accumulation in the no-till soil

The C accumulation in the no-till soil


-2

0

2

4

6

8

10SO

C (M

g ha

-1) 0-2.5 cm 2.5-5 cm 5-10 cm

LSD 0.05

1.0

-0.2

0.0

0.2

0.4

0.6

0.8

PNF-

1

TN (M

g ha

-1)

NT-1

0NT

-20

NT-2

2CT

-22

PNF-

1NT

-10

NT-2

0NT

-22

CT-2

2

PNF-

1NT

-10

NT-2

0NT

-22

CT-2

2

LSD 0.05


Depth PNF-1 NT-10 NT-20 NT-22 CT-22

------------------- % ----------------------

SOC from each treatment compared with NF as a base line

(cm)

0-2.5

2.5-5

5-10

+ 6.9

+ 26.6

+ 26.1

+ 19.6

+ 8.8

- 2.5

+ 43.2

+ 35.1

+ 15.4

+ 75.4

+ 56.1

+ 15.8

- 13.5

- 7.2

- 1.6


Depth PNF NT-10 NT-20 NT-22 CT-22

(cm)

0-2.5 +6.9 +19.6 +43.2 +75.4 -13.5

2.5-5 +26.2 +8.8 +35.1 +56.1 -7.2

5-10 +26.1 -2.5 +15.4 +15.8 -1.6

10-20 +32.8 -14.5 +12.5 +5.9 +4.2

20-40 +16.8 -9.3 +10.5 +4.9 +2.7

-------------------- % ---------------------

The total SOC gain or losses from each site compared with the native field


1st 10 years 2nd 10 yearsDepth (cm)

0-2.5

2.5-5

5-10

10-20

20-40

0.21 0.42

0.08 0.32

-0.04 0.24

-0.37 0.51

-0.37 0.57

----------- Mg ha-1yr-1 --------

Carbon increment rates in a first and second 10 years in a chronosequence


carbon cycle in terrestrial environment -...

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