Characterization of soil organiccarbon and its fraction labile carbon
in ecosystems
Ľ. Pospíšilová, V. Petrášová, J. Foukalová, E.
PokornýMendel University of Agriculture and Forestry,
Department of Agrochemistry, Soil Science, Microbiology
and Plant utrition, MZLU, Zemědělská 1, 613 00 Brno,
Czech Republic

Humic Substances in Ecosystems 8, Šoporňa 13.-17.9.2009 Slovakia

Long-term field experiments – a part of theproject “Biological and technological aspectsof sustainability of controlled ecosystems andtheir adaptation to climate changes”
 SOM quality

 Physical properties Chemical properties
 Biological properties
Humic Substances in Ecosystems 8, Šoporňa 13.-17.9.2009 Slovakia

Organic carbon undergoes short and long termtransformation in the soil. Under a dynamic
equilibrium a portion of organic carbon ismineralized, and the same portion is newly
formed• Stable carbon (TOC, HS, HA and FA sum)
• C labile (hot water extractable)• C microbial (bacterial biomass)

Humic Substances in Ecosystems 8, Šoporňa 13.-17.9.2009 Slovakia

Aim of our study• Total carbon content• HS quality• HA quality - 13C 6MR analysis• Labile carbon content• Bacterial biomass amount (Cmic)• Basal respiration

Humic Substances in Ecosystems 8, Šoporňa 13.-17.9.2009 Slovakia

Land use:
Arable soils x Grassland(locality Vatín)

Humic Substances in Ecosystems 8, Šoporňa 13.-17.9.2009 Slovakia

Localities
Cambisols
Locality Subtypes

GPS

GPS Atitude (m)6EO

m.a.s.l.

Land use
Vatín Eutric C. arable 49° 31,091´ 15° 58,196´
6áměšť Haplic C. arable 49° 12,808´ 16° 9,757´
Vatín Eutric C. grassland 49° 31,091´ 15° 58,196´Ocmanice Leptic C. grassland 49° 13,909´ 16° 7,782´
Humic Substances in Ecosystems 8, Šoporňa 13.-17.9.2009 Slovakia

530430531450Basic soil characteristics

Soil types
Leptic C.
Haplic C.
Eutric C. 1
Eutric C. 2

pH/H2O pH/KCl
4.1
5.1
5.1
4.9

54
4.8
4.4

Texture classes (%)
2,00-0,05 0,05-0,002 < 0,002mm
50
40
9.5
0
81.6
18.4
55
35.0
9.5
72.2
17.7
10.1

Humic Substances in Ecosystems 8, Šoporňa 13.-17.9.2009 Slovakia

Haplic Cambisol(Náměšť n/O, arable soil.)

Humic Substances in Ecosystems 8, Šoporňa 13.-17.9.2009 Slovakia

Leptic Cambisol(Ocmanice, grassland)

Humic Substances in Ecosystems 8, Šoporňa 13.-17.9.2009 Slovakia

Methods of study TOC and 6itrogen content (LECO-CNS analyzer)
 C labile (hot water extraction method) HS fractionation (short fractionation method), HA isolation(IHSS method)
 13C 6MR (Varian INOVA 600 spectrometer)
 Cmic =Bacterial biomass (Fumigation extraction method) Basal respiration (Apparatus Vaisala GMT222)
 A6OVA
Humic Substances in Ecosystems 8, Šoporňa 13.-17.9.2009 Slovakia

TOC content in Eutric Cambisol (Vatín)

2,5TOC,%

21,5Grassland
Arable10,50years
Humic Substances in Ecosystems 8, Šoporňa 13.-17.9.2009 Slovakia

Labile carbon content in Eutric Cambisol(Vatín)
700

Clabile, mg/kg

600
500
400
300

Grasslandarable200
1000years
Humic Substances in Ecosystems 8, Šoporňa 13.-17.9.2009 Slovakia

Correlation between TOC and Labile carbon
7,5
7
6,5
6
5,5
5
4,54C la b [ m g /g ]y = 1,6929x + 3,2458
R2 = 0,7021

1

1,2

1,4

1,6

1,8

2

2,22,4TOC [mg/100g]
Humic Substances in Ecosystems 8, Šoporňa 13.-17.9.2009 Slovakia

Results• After 10 years of experiment TOC and C
labile content were higher in grassland• Correlation between TOC and Labile carbon
content was found (R= 0.84)• Statistically significant differences between
arable soils and grassland in TOC and labilecarbon were foundHumic Substances in Ecosystems 8, Šoporňa 13.-17.9.2009 Slovakia

Humic substances qualityCambisols
TOC Clabile

HS sum HA sum FA sum HA/FA HD Q4/6

(%)

mg/kg

mg/kg

mg/kg

mg/kg

Leptic C.

3.84

607

4.141.44

2.7

0.4

45.7

Haplic C.

2.23562

4.65

1.6

30.5

95.7

Eutric C. 1

1.97

500

6.8

1.8

50.5

108.3

Eutric C. 2

2.26

560

7.6

2.9

4.7

0.6

13.3 9.1

subtypes(%)

Humic Substances in Ecosystems 8, Šoporňa 13.-17.9.2009 Slovakia

Humic acids quality
C
Humic acid ( at. %)H(at. %)

6(at. %)O( at. %)Ash(%)

LepticCambisol

33.45

47.44

3.07

16.05

1.7

HaplicCambisol

34.20

46.16

3.05

16.59

4.08

EutricCambisol 1

32.73

46.48

2.52

18.27

9.62EutricCambisol 2

35.59

45.89

2.64

15.88

8.44

Humic Substances in Ecosystems 8, Šoporňa 13.-17.9.2009 Slovakia

13C 6MR spectra of HA(Eutric C. 1, Vatín)

Humic Substances in Ecosystems 8, Šoporňa 13.-17.9.2009 Slovakia

13C 6MR spectra of HA(Eutric C. 2 Vatín)

Humic Substances in Ecosystems 8, Šoporňa 13.-17.9.2009 Slovakia

13C 6MR spectra of HA(Haplic C. 6áměšť)Humic Substances in Ecosystems 8, Šoporňa 13.-17.9.2009 Slovakia

13C 6MR spectra of HA(Leptic C. Ocmanice)

Humic Substances in Ecosystems 8, Šoporňa 13.-17.9.2009 Slovakia

Results and discusion• Elemental analysis showed that carbon content
was decreasing in order:
Eutric C. (2) > Haplic C. > Leptic C. > Eutric C. (1)• HA structure was affected by soil type and landuse
• HA were young, 13C 6MR spectroscopy showed
higher aromatic carbon content in grassland andaliphatic carbon in arable soils
Humic Substances in Ecosystems 8, Šoporňa 13.-17.9.2009 Slovakia

Chemical and Biological properties
pH/H2O

pH/KClSoil types%C%6mgCO2/ Complex
C/6 100g /h factor

Leptic C.

54.2

3.84

0.4

9.7

0.32

2.1

Haplic C.

5.1

4.2

2.23

0.3

8.35

0.21

1.6

Eutric C. 1

5.1

4.6

1.97

0.2

9.23

0.41

1.1

Eutric C. 2

4.9

4.4

2.26

0.25

90.60

1.22

Humic Substances in Ecosystems 8, Šoporňa 13.-17.9.2009 Slovakia

Biological properties
Cmic/
TOC

Soil

Cmic

B/CmicB/G

Typesµg/g dw

Leptic C.

249.9

0.42

8.7*10-4

0.2

0.004

Haplic C.

112.5

0.2

2.7*10-3

0.15

0.018

Eutric C.
1

86.9

0.17

4.7*10-3

0.1

0.045

Eutric C.
22150.4

2.8*10-3

0.14

0.021

qCO2G/Cmic
qCO2

Humic Substances in Ecosystems 8, Šoporňa 13.-17.9.2009 Slovakia

Results of microbial transformation:•CO2 output and bacterial biomass amount higher in grassland•Ratio Cmic /TOC was lower in arable soil = influence of land use•

Decomposition rate (qCO2 = B/Cmic) higher in arable soils

CO2Soil, residu
esHumic Substances in Ecosystems 8, Šoporňa 13.-17.9.2009 Slovakia

Conclusions
1. More TOC, C labile, Cmic, and HS in grassland
2. 13C MR analysis: more aromatic compounds in HA isolated from grassland higher HD in HA isolated from grassland
3. Higher decomposition rate in arable soils
4. Complex factor calculated from biological properties
showed higher HS stability in grassland

Humic Substances in Ecosystems 8, Šoporňa 13.-17.9.2009 Slovakia

Acknowledgements
Thanks to prof. Marta Tesařová anddoc. Tibor Liptaj, CSc. – for advices,help and 13C 6MR measurements

Humic Substances in Ecosystems 8, Šoporňa 13.-17.9.2009 Slovakia

Thank you for your attention!

Humic Substances in Ecosystems 8, Šoporňa 13.-17.9.2009 Slovakia