1

Soil Carbon Sequestration: Long-term Effect of Tillage and Rotations

Charles W. Riceand

Karina Fabrizzi

October 28-30, 2008

Kansas State University

Energy supply

0

1

2

3

4

5

6

7GtCO2-eq

Transport Buildings Industry Agriculture Forestry Waste

Non-OECD/EI TEITOECDWorld total

US$/tCO2-eq

Global economic mitigation potential for

different sectors at different carbon prices

IPCC, 2007

Agriculture

• A large proportion of the mitigation potential of agriculture (excluding bioenergy) arises from soil C sequestration, which has strong synergies with sustainable agriculture and generally reduces vulnerability to climate change.

• Agricultural practices collectively can make a significant contribution at low cost – By increasing soil carbon sinks, – By reducing GHG emissions, – By contributing biomass feedstocks for energy use

IPCC Fourth Assessment Report, Working Group III, 2007

Agriculture• Cropland

– Reduced tillage– Rotations– Cover crops– Fertility management– Erosion control– Irrigation management

• Rice paddies– Irrigation– Chemical and organic fertilizer– Plant residue management

No-till seeding in USA

Rice fields in The Philippines

Maize / coffee fields in Mexico

• Agroforestry

– Improved managementof trees and cropland

Agricultural Management Strategies for C Sequestration

Enhance C Inputs Reduce C losses

Crop Management Tillage

Crop Selection Fallow Management

Crop Rotations

Develop Agricultural Management Programs that:

Soil Microbial ActivitySoil Microbial Activity

Soil Organic Matter (C)Soil Organic Matter (C)

CO2CO2

Harvestable Yield

Harvestable Yield

SunlightSunlight

ClimateClimate

SoilsSoils ManagementManagement

Potential C sequestration in U.S

Lal et al., 1999, Post et al.,2004

Strategies Management practices Mg C ha-1 yr-1

Decreasing tillage intensity Reduced tillage, no-tillage, mulch tillage

0.24-0.40

Increasing amount of crop residue return

High residue crops, applications of manure and biosolids, erosion control, irrigation, integrated pest management, precision agriculture

Use of winter cover crops 0.1-0.3

Summer fallow elimination 0.1-0.3

Fertilizer management 0.05-0.15

Perennial vegetation CRP 0.3-0.7

8

Corn production in NE Kansas

• Continuous corn• 168 kg N/ha• Tillage Systems

– No-tillage– Conservation tillage (Chisel-disk)

• 15 year analysis

Soil C stocks after 18 years

0 20 40 60 80 100 120

0-60

30-60

15-30

5-15

0-5NTCT

9

*

*

*

Nicoloso et al., 2008

Tillage effects on soil organic C by depth, Minnesota: 14 y continuous corn

Mg C/ha/cmDepth No-till Plow

0.7.5 4.49 3.89 **

7.5-15 4.94 4.66

15-30 3.51 3.17

30-45 2.45 1.48 **

0-45 (Mg/ha) 160 133 **

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Huggins et al., 2007

E

A

Change in management

Years of cultivation

SO

C le

vels

(M

g C

ha

-1)

O

Soil C sequestration rates for 15 years(Mg C/ha/y)

Depth Fertilizer NTilled

Fertilizer NNo-till

Manure NTilled

Manure NNo-till

cm

0-5 0.161 0.351 0.393 1.182

0-15 0.254 0.497 0.792 1.402

0-30 0.336 0.717 0.839 1.387

0-60 0.146 1.325 0.733 1.141

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• NT > Tilled, but tilled had some increase• Added C (manure) is less conserved in tilled• What is baseline? Nicoloso et al., 2008

E

D

C

AChange in management

Years of cultivation

SO

C le

vels

(M

g C

ha

-1)

O

Net effect of NT for 15 yearsNT (0-15y) –T (0-15y)

Depth No N0.5

Fertilizer N Fertilizer N0.5

Manure N Manure N

cm Mg/ha/y

0-5 0.187 0.450 0.190 0.468 0.789

0-15 0.182 0.371 0.243 0.402 0.610

0-30 0.174 0.311 0.381 0.417 0.548

0-60 -0.443 -0.191 1.179 0.961 0.408

14Nicoloso et al., 2008

Carbon sequestration rate (C rate) expressed in equivalent mass (Mg C/ha/y) to a 30 cm depth except for Hayes (15 cm)

Location Rotation Duration CT RT NT

Hayes Wheat-Sorg-F 37 y 0.008 0.020 0.055

Parson Sorg-Soy 20 y 0.234 0.370 0.420

Ashland Average 29 y 0.269 0.346 0.384

Tribune Wheat-Sorg-F 15 y -0.570 -0.503 -0.392

15Fabrizzi, 2006

04/19/23

16

30

35

40

45

50

55

60

30 35 40 45 50 55 60

SOC using CT (Mg C ha-1) at 0-30 cm

SO

C u

sin

g N

T o

r R

T (

Mg

C h

a-1

) at

0-3

0 cm

Ashland RT Ashland NT

Parsons NT Tribune RT

Parsons RT Tribune NT

Hays NT Hays RT

SOCNT = 1.14x - 4.90 R2 = 0.76

SOCRT =1.08x - 3.14 R2 = 0.67

1:1 Line

Intergovernmental Panel on Climate Change (IPCC): 1.1 for CT to NT West and Post (2002): 1.16 for CT to NT

Fabrizzi, 2006

Carbon sequestration rate (C rate) expressed in equivalent mass (Mg C/ha/y) to a 15 cm depth as a function of N rate (kg N/ha/y)

located Hayes, Kansas, USA

Rotation Duration 0 N 22 N 45 N 67 N

Wheat-Sorg-F 37 y 0.007 0.012 0.035 0.057

17Fabrizzi, 2006

Carbon sequestration rate (C rate) expressed in equivalent mass (Mg C/ha/y) to a 30 cm depth for Manhattan, KS USA

Rotation

Continuous Soybean 0.066

Continuous Sorghum 0.292

Continuous Wheat 0.487

Soybean - Wheat 0.510

Soybean - Sorghum 0.311

18Fabrizzi, 2006

Physical Protection

Chemical

Microbial composition and activity

Substrate

quality

Plant

characteristics

H2O

Temperature

Clay

Biological

factors

Organics

Clay

Organic C

CO2

O2

Disturbance

Conservation of Soil Carbon

Hie

rarc

hy

of

imp

ort

an

ce

Mineralogy

• Fungal Role (18:2w6 biomarker)

• Significant tillage X residue interaction (p<0.05)

0

0.02

0.04

0.06

0.08

CT + No R CT + Residue NT + No R NT + Residue

c*

a

b

c

Mo

le F

rac

tio

n

Frey et al. (1999) found greater fungal networks optically in NT as compared to CT for the same soil.White and Rice, 2007

Plant C

SOM SOM

CO2 CO2

FungiFungi

Micro-aggregates

No-Till = Lower disturbance

Soil MacroaggregateSoil Macroaggregate

Tillage = Higher disturbance

Plant C

SOM SOM

CO2 CO2

FungiFungi

Micro-aggregates

No-Till = Lower disturbance

Soil MacroaggregateSoil Macroaggregate

Tillage = Higher disturbance

Plant C

SOM SOM

CO2 CO2

FungiFungi

Micro-aggregates

No-Till = Lower disturbance

Soil MacroaggregateSoil Macroaggregate

Tillage = Higher disturbance

White and Rice, 2007

YMollisol = 1.48 SOC - 8.2

R2 = 0.9245

YVertisol= 1.56 SOC - 2.83

R2 = 0.1292

YOxisol= 0.58 SOC - 6.9

R2 = 0.3344

0

10

20

30

40

50

60

70

80

0 10 20 30 40 50 60 70

SOC (g C kg-1)

Am

ou

nt

of

ma

cro

ag

gre

ga

tes

(g 1

00

g-1

so

il)

Fabrizzi, 2006

Soil

Organic

Carbon

MicrobialActivity

Nutrient

Cycling

Soil

Structure

Soil

Biodiversity

WaterErosion

&

Availability

Gaseous Gaseous EmissionsEmissions

Plant Growth

Yield

Environmental Environmental ServicesServices

SustainabilitySustainability

No-Tillage Cropping SystemsNo-Tillage Cropping Systems

Conservation AgricultureConservation Agriculture

•Restores soil carbon

•Conserves moisture

•Saves fuel

•Saves labor

•Lowers machinery costs

•Reduces erosion

•Improved soil fertility

•Controls weed

•Planting on the best date

•Improves wildlife habitat

SummarySummary• Soil C sequestrationSoil C sequestration

– Need to examine the systemNeed to examine the system• Less disturbanceLess disturbance• Organic C inputsOrganic C inputs

– No-tillage must be combined with residuesNo-tillage must be combined with residues• Residue removal in no-till may be worst than tillage Residue removal in no-till may be worst than tillage

with residuewith residue

• Agricultural soil C sequestrationAgricultural soil C sequestration– Keeps land in production in some casesKeeps land in production in some cases– In many cases increases profitability for the farmerIn many cases increases profitability for the farmer– Provides other environmental benefits to societyProvides other environmental benefits to society

• Soil and Water quality (less runoff, less erosion)Soil and Water quality (less runoff, less erosion)– May help adapt to climate change as well as mitigateMay help adapt to climate change as well as mitigate

• Websiteswww.soilcarboncenter.k-state.edu/

K-State Research and ExtensionK-State Research and Extension

Chuck Rice

Phone: 785-532-7217

Cell: 785-587-7215 cwrice@ksu.edu

04/19/23

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Treatment Scenario Rate

(Mg C/ha/y)

State

Eliminate summer fallow

3-year system

4-year system Continuous cropping

0.073

0.117

0.229

Eastern Colorado

NT (corn) NT 150 N Fert 0.80 NE Kansas

Rotations CT - NT wheat

CT - NT sorghum

CTsorg/NTwheat to NT sorg/wheat

0.764

0.605

0.624

SC KS

CRP 0.80 NE