Transcript Soil Carbon Baselines

Kearney Foundation of
Soil Science
Soil Carbon and California
Terrestrial Ecosystems
Director: Kate Scow
UC Davis
Martin
Theodore
Kearney’s
endowment
•Kearney Foundation of Soil
Science established 1951.
•5-year missions address
public concerns in CA and
support research in soils,
plant nutrition and water
science
SOIL CARBON CYCLE
2001-2006: Soil Carbon and California
Terrestrial Ecosystems
•Understand mechanisms and processes governing
storage and flow of carbon in soils of CA's diverse
ecosystems;
•Quantify impacts of inputs of water, nutrients, and
pollutants, as well as physical disturbance, on storage,
transformations and transport of carbon in soils;
•Assess roles of soils in emissions and consumption of
greenhouse gases,
•Identify and analyze strategies and policy options for soil
carbon management
Projects Funded:
• 25 “traditional” research projects
across UC campuses
•3 projects funded in special call for
research on soil carbon in joint California
Dept of Food & Agriculture Specialty
Crops/Kearney Foundation
•9 graduate fellowships in soil carbon
Kearney Sponsored Workshop on Soil Carbon
Sequestration: Interface Between Science and
Policy (Sept 22, 23, 2003)
1. What are on-going efforts in the science and policy of
C sequestration in Europe, Canada and US?
How does soil science, resource economics and policy
analysis interact in developing policy on C sequestration?
2. What are on-going efforts in climate change
assessment and mitigation in the State of California?
Estimation of C sequestration potential in CA soils and
other reservoirs.
3. Presentation of Kearney-funded research on soil
carbon in California terrestrial ecosystems.
Soil Carbon Sequestration; history and projections
MECHANISMS FOR ENHANCING SOIL
CARBON SEQUESTRATION
REDUCE C
LOSS
BY REDUCED
TILLAGE
PROMOTE
MICROBIAL
COMMUNITIES
WITH HIGHER C
CONTENT
INCREASE CROP
INPUTS OF C BY
HIGHER YIELDS
OR LESS
FALLOW
PERIODS
GROW CROPS
THAT SEQUESTER
MORE C, GROW
COVER CROPS,
LEAVE MORE
STUBBLE
INCREASE
PRODUCTIVITY
OF MARGINAL
LANDS
Estimated rates of C sequestration in soil within US:
75-200 Tg C in croplands (Lal et al. 1998)
30-90 Tg C in grazing lands (Follett et al. 2001)
•Assumes widespread adoption of improved management
practices.
•Does not account for changes in other biogenic greenhouse
gases (nitrous oxide and methane) that may be by-products of
management changes.
THUS C sequestration in terrestrial ecosystems can
account for about 6.4% of emissions (based on 5000
Tg C per yr in 1990).
Management-induced C sequestration in soil is only a temporary
and partial solution to the greenhouse gas problem.
Other benefits of increased soil carbon
Projects on soil carbon
sequestration
•Scoping study in joint CEC/Kearney/
CDFA project.
•Upcoming call for proposals from joint
CEC/Kearney/CDFA to conduct pilot
study to estimate carbon sequestration
potential study in CA agricultural county.
SCOPING STUDY: County scale
assessment of carbon
sequestration and trace gas
emission from California
croplands
William Salas1, Marc Los Huertos2 and
Changsheng Li3
1Applied
GeoSolutions, LLC, 10 Newmarket Road, Durham,
NH, 03824
2Center for Agroecology and Sustainable Food Systems,
University of California Santa Cruz
3 Complex Systems Research Center, University of New
Hampshire, Durham, NH 03824
Figure 2
The DNDC Model
Ecological
drivers
Climate
Vegetation
Soil
Anthropogenic activity
Plant growth
Daily water
demand
Daily potential
ET
Annual average
temperature
Daily biomass
accumulation
( LAI )
Water uptake
by roots
Very labile
litter
CO2
N demand
LAI-regulated
albedo
Evaporation
Water stress
Water flow
between layers
Transpiration
Stalks
Soil temperature
profile
Soil moisture
profile
Oxygen
diffusion
Soil Eh
profile
Resistant
litter
Labile microbes
Resistant microbes
Labile humads
Resistent humads
NH4
Daily N uptake
by roots
Root respiration
Labile
litter
Grain
Roots
Oxygen
consumption
DOC
Passive humus
Soil climate
Effect of temperature and moisture on decomposition
Soil
environmental
variables
Temperature
NO2 -
Nitrate
denitrifier
Moisture
NO3
-
pH
DOC
Decomposition
Substrates (NH4+, NO3- and DOC)
Eh
Nitrifiers
NH4+
Soil Eh
CH4 production
Aerenchyma
CH4 oxidation
NO
Nitrite
denitrifier
N2O
NH3
NO3-
Clay-NH4+
DOC
N2
DOC
N2O
denitrifier
N2O
Denitrification
Nitrification
NO
NH3
Fermentation
CH4 transport
CH4
Soil carbon
content
Scaling Up Approaches
from Site to Regions
Field & lab
experiments
Model
development:
predicting
biochemical &
geochemical
processes at site
scale
Soil fertility determined
by soil organic matter
storage
Soil carbon content
Crop yield
Statistical data
collection
Remote sensing
data acquisition
GIS database
construction:
providing climate,
soil, vegetation, and
management
data at regional
scale
Remote sensing
analysis:
improving crop
acreage data &
providing phenology
data
Modeling
with
DNDC
Emissions of CO2, CH4,
N2O, NO, N2, and NH3
Leaching of nitrate
Soils
• NRCS STATSGO Soils data
 DWR crop area mask
 Derived area weighted statistics of range (min,
max) in SOC, pH,
texture (%clay),
and bulk density
by county
County Agricultural Data
• Various Sources of
California data: County
Commissioners Reports,
FRAP (Fire Resource &
Assessment Program,
CDF), NASS, DWR
• Used DWR mid-1990s
data:
– Sub-county spatial
resolution
– Based on Aerial Photos
coupled with field surveys
– Total crop area: 38,344km2
GIS Database
Next Steps
• Fertilizer: use different application rates across
regions
• Soils: Use crop class specific soils data at the
county scale. Merge DWR and STATSGO
• Validation analyses for California. Need to collect
existing data.
– Long-term SOC changes.
– N2O data
– CH4 from rice
• Evaluate scenarios for C sequestration: cover crops,
conservation tillage, no till, climate change, …
• Run 20 and 40 year scenarios to examine C
sequestration capacity and net GWP (N2O offsets)
EXAMPLE OF OTHER KEARNEY FUNDED RESEARCH
1. Stabilization of organic matter in soils
*Litter quality (e.g., C/N, tannins, lignin, etc.) in regulating organic matter
turnover
*Litter diversity in affecting microbial function and soil C dynamic
*Pedogenic factors in regulating soil carbon storage
*Carbonate chemistry as a source/sink of carbon in soils
2. Transformation of trace gas in soils
*Microbial processes on the dynamics of trace gas formation
*Factors affecting trace gas fluxes between the atmosphere and soil
3. Impacts of management
*Effect of management practices (N fertilization, irrigation, minimum tillage,
wetland drainage) on carbon storage and trace gas dynamics
*Soil carbon sequestration effects on fertilizer use efficiency
*Role of soil carbon in maintaining surface and subsurface water quality
*Development of water storage strategies through enhanced soil structure and
water penetration
4. Scaling of research results to regional and global
scales
*Soil carbon and trace gas dynamics on the small watershed scale (5
- 100 hectares)
*Hydrologic conditions on soil carbon and trace gas dynamics
*Landscape scale evaluation of global climate change and it
relationship to soil organic matter storage and trace gases dynamics
5. Policy and Economics
*Regional and global policy considerations to maintain
environmental quality
*Economic and policy analysis of agricultural productivity and
sustainability