Clima Climate, W Water ter, and Ecosy and Ecosystems: tems: A - - PowerPoint PPT Presentation
Clima Climate, W Water ter, and Ecosy and Ecosystems: tems: A Futur A Future of of Sur Surprises prises Robert Harriss Houston Advanced Research Center Changsheng Li Changsheng Li Steve Frolking University of New Hampshire Climate
Robert Harriss Houston Advanced Research Center Changsheng Li Changsheng Li Steve Frolking University of New Hampshire
Climate change is not uniform geographically
A T f 2001 2005 d t 1951 80 d C Average T for 2001-2005 compared to 1951-80, degrees C
And T is not the only factor that’s changing
NCDC, 2000
Effect is not uniform; most places getting wetter, some getting drier.
Mitigation and Adaptation to Climate Change By Design Change By Design
methane, nitrous oxide, CFC’s, ozone, and black soot also contribute to climate change. g
Significant climate change mitigation benefits can be derived by reducing nitrous oxide and methane emissions from agriculture.
Climate forcing agents in the industrial era. “Effective” forcing accounts for C ate o c g age ts t e dust a e a ect e
“efficacy” of the forcing mechanism
Source: Hansen et al., JGR, 110, D18104, 2005.
Inefficiencies in fertilizer nitrogen use offer important opportunities for mitigation of important opportunities for mitigation of nitrous oxide emissions
N Fertilizer Produced N Fertilizer Applied N in Crop N In Feed N in Store N Consumed
100 4 47 94 7 31
6 47 3 24 16
4% of the N produced in the Haber-Bosch process and used for animal production enters the human mouth.
Galloway JN and Cowling EB. 20
DNDC Reveals the mechanisms that drive ecosystem change by tracking movement of chemical elements between life and its environment chemical elements between life and its environment DNDC allows users to construct scenarios that DNDC allows users to construct scenarios that benefit land managers and enhance environmental protection. DNDC can stimulate innovation and information h i l t t ti b tt l d sharing relevant to creating better landscape management for people and nature
N N inputs N2 p HNO3, etc N2O, N2, NOx gas losses Plant N NH4
+
N N distribution NH4 NO3
N distribution Microbial N Soil N leaching N losses
NO Particulate Matter Stratospheric effects N2O
Atmosphere
NO x Ozone effects effects NH3 NHx NOy NO Greenhouse effects N2O Energy production
Terrestrial Ecosystems
NH3 Forests & G l d NOy NOx NH NHx Food production Plant Agroecosystem effects Crop Animal Grasslands effects N2O NHx NOy People (food; fiber) Norganic Surface water NO3 Soil Soil Coastal effects (terrestrial) N2O Groundwater effects Surface water effects Ocean effects
Aquatic Ecosystems
(aquatic)
y et al., 03
Indicates denitrification potential
Galloway 200
The DNDC Model
ecological drivers Climate Soil Vegetation Human activity drivers
litter
water demand water uptake daily growth annual average
soil temp vertical water flow very labile labile resistant labile resistant microbes humads
CO2 NH4
+
stem s grain N-demand N-uptake water uptake water stress root respiration potential evapotrans.
LAI-regulated albedo
evap. trans. temp.
Decomposition Plant growth Soil climate
profile soil moist profile soil Eh profile O2 diffusion O2 use flow labile resistant passive humus
DOC roots s root respiration effect of temperature and moisture on decomposition
soil environmental factors Temperature Moisture pH Substrates: NH4
+, NO3
DOC Eh
NH4
+
clay- NH + NH3 DOC nitrifiers NO3
NO N2O NO2
denitrifier nitrite CH4 CH4 production CH4 oxidation soil Eh aerenchyma
Denitrification Nitrification Fermentation
NH4
+
N2O NO NH3 NO3
N2 nitrite denitrifier N2O denitrifier CH4 oxidation CH4 transport aerenchyma DOC
DNDC bridges between inputs and outputs
Cli t
INPUT INPUT INPUT OUTPUT PROCESSES
Climate
Used by soil microbes Emissions of N2O, NO, N2, CH4 and CO2 Soil properties
DNDC
2 Plant soil C dynamics Availability
C titi pH Management Crop rotation
NH4, NO3, and DOC Competition N leaching
Used by plants Growth of crop biomass
Model performance can be tested based on short- or long-term observations on C fluxes long term observations on C fluxes
N2O Fluxes from a Organic Soil at Glades, Florida, 1979-80 g
4500 5000 3000 3500 4000
/day
2000 2500 3000
2O flux, g N/ha
1000 1500
N2
500 106 123 140 157 174 191 208 225 242 259 276 293 310 327 344 361 13 30 47 64 81 98 115 132 149 166 183 200 217 234 251 268 285 302 319 336 353
Day
Field Model
Observed and Modeled N2O and NO Emissions from a Spruce Stand at Hoglwald Forest in Germany in 1995 1997 Stand at Hoglwald Forest in Germany in 1995-1997 N2O NO
Observed and DNDC-Modeled N2O Fluxes from Agricultural Soils in the U.S., Canada, the U.K., Germany, New Zealand, China, Japan, and Costa Rica
1000
R2 = 0.84
100
/ha/year
0.4 0. 0.34 0.41
R 0.84
10
O flux, kg N/
0. 0.4 0.37 0. 0.037 0.43 0.032 0.032 0.035 0.011
1 0 1 1 10 100 1000
Modeled N2O
0.032 0. 0.033 0.050.032 0.015 0.035 0.029 0.035 0.028 0.031 0.05 0 029
0.1 0.1 1 10 100 1000
M
0.029 0.029 0.006 0.01 0.019 0.019 0.02 0.025 0.025 0.01 0.015
Observed N2O flux, kg N/ha/year
Sensitivity of N2O flux to environmental factors
Goal: Predicting impacts of management alternatives
A change in management
Climate Vegetation Soil Other management Yield C t T N leaching C storage Trace gas
A scenario of best management practices A scenario of best management practices was composed with (1) no-till, (1) increased depth of fertilizer application (1) increased depth of fertilizer application, (3) three splits of fertilizer application, and (4) non-legume cover crop (4) non legume cover crop.
Impacts of conventional tillage (CT), no-till (NT) and best t ti (BMP) f fi ld management practices (BMP) for a crop field at Story County, Iowa
CT NT BMP Unit F tili 120 120 120 k N/h Fertilizer use 120 120 120 kg N/ha Crop yield 4188 3830 4138 kg C/ha p y g dSOC
415 996 kg C/ha N leaching 47 20 8 kg N/ha N2O 19 28 16 kg N/ha N2O 19 28 16 kg N/ha
significant reductions in nitrous oxide emissions while i i i i ld C b fi i l d maintaining crop yields. Co-benefits can include reductions in water pollution that results from leaching of nitrate.
management issue to achieve maximum benefits.
The DNDC precision management tool can also be applied to the management of timber, pastures, rice, and other landscapes.
fast-track approach to reductions in nitrous oxide emissions and nitrate pollution.
Uncertainties, unclear signals, and long time scales are characteristic of climate, water, and ecosystem interactions We argue that there and ecosystem interactions. We argue that there is a strong rationale for enhanced policy flexibility and innovation using a portfolio of reactive, adaptive, and precautionary land e c ve, d p ve, d p ec u o y d management strategies.