Biological, Chemical and Physical

1
Biological, Chemical and Physical Sequestration
of Soil Carbon in Response to Tillage Islam,
K.R. and A. Sundermeier hio State University
2
(No Transcript)
3
Global dimming 2.7 in sunlight/decade
4
Fossil fuel consumption
5
Brickfields in Bangladesh
6
(No Transcript)
7
Uzbekistan
8
Conventional agriculture
9
Grape vineyard in Uzbekistan
Uzbekistan village
10
Burning of grasslands in Tajikistan
Grazing in Tajikistan
11
(No Transcript)
12
In response to ?CO2 in the system, we found
13 - 62 in shoot yield production 65 -
143 in root production On average, 37 in
plant production
13
NT may enhance C sequestration and improve soil
quality
14
C sequestration response (Domino effect)
SOC
Humic C
POM (C)
Active C
Microbial biomass
Plant residues
15
Materials and Methods
16
Site NW Branch of the Ohio Agricultural
Research and Development Center, Wood
county, Ohio Design RCB with 4
reps Treatment Conventional tillage for corn
(CT) No-till for corn (NT) NT-2 yr
(NT2) NT-8 yr (NT8) NT-40 yr
(NT40) Plot size 50 m x 30 m Soil series
Hoytville Clay Loam
17
Fifteen soil cores were collected from each plot
by following GPS guided systematic
sampling. Soil cores were segmented at 0 -7.5,
7.5 - 15, 15 - 22.5 and 22.5 30 cm depth,
respectively. Soils were sieved through a 2 mm
mesh prior to analysis. Soil biological
properties were measured or soils were incubated
within 48 h of sampling
18
Biologically defined soil C pools Microbial
biomass C Soil basal respiration rates
Maintenance respiration rates (qCO2)
Chemically defined soil C pools Active C (0.02M
KMnO4 oxidation) 0.1M Na4P2O7 extractable C
Physically defined soil C pools Particulate
organic matter (C) Macro-aggregate protected C
19
Results and Discussion
20
(No Transcript)
21
(No Transcript)
22
(No Transcript)
23
Biological indicators of soil C sequestration
24
(No Transcript)
25
(No Transcript)
26
(No Transcript)
27
(No Transcript)
28
Chemical indicators of soil C sequestration
29
(No Transcript)
30
(No Transcript)
31
(No Transcript)
32
(No Transcript)
33
Physical indicators of soil C sequestration
34
(No Transcript)
35
(No Transcript)
36
(No Transcript)
37
Conclusions Soil C sequestration under NT system
is due to Deposition of plant residues on the
surface, less oxidative environment, energy
efficient biological system (qCO2), and greater
protection of residues (POM) than CT system
C loss by CT system 164 29 kg ha-1 y-1 C
regain by NT system 351 53 kg ha-1 y-1 C
recovery in 40-y NT soil 57 11 kg ha-1 y-1
38
Early response of soil biologically defined C
pools (microbial biomass and qCO2) is
responsible for initiation of soil C
sequestration through energy- use efficiency
(qCO2) followed by greater physical protection
of fragmented plant residues (POM) under NT
system
Lower sensitivity of soil chemically defined C
pools (especially extractable and total organic
C) in response to tillage systems over a short
period of time (1 - 3 years) may underestimate
soil C sequestration due to greater proportions
of background recalcitrant C
39
(No Transcript)