involving leguminous crop rotation as climate …...climate adaptation 2014: future challenges...
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Climate Adaptation 2014: Future Challenges WWW.DPI.NSW.GOV.AU
Involving leguminous crop rotation as climate change adaption option
also as lower nitrous oxide emissions from dryland cropping
Yuchun Ma1,2,3, Graeme Schwenke4, Bin Wang1,5, De Li Liu1,2, Muhhuddin Anwar1,2
1 NSW Department of Primary Industries, Wagga Wagga Agricultural Institute, Wagga Wagga, NSW 2650, Australia
2 Graham Centre for Agricultural Innovation, PMB, Pine Gully Road, Wagga Wagga, NSW 2650, Australia
3 College of Applied Meteorology, Nanjing University of Information Science & Technology, Nanjing, Jiangsu 210044, China
4 NSW Department of Primary Industries, 4 Marsden Park Road, Tamworth, NSW 2340, Australia
5 Plant Biology and Climate Change Cluster, University of Technology Sydney, PO Box 123, Broadway, NSW 2007, Australia
Climate Adaptation 2014: Future Challenges WWW.DPI.NSW.GOV.AU
Background
IPCC 2013
History Future
RCP2.6
RCP8.5
Climate Adaptation 2014: Future Challenges WWW.DPI.NSW.GOV.AU
IPCC 2013
History Future
Climate Adaptation 2014: Future Challenges WWW.DPI.NSW.GOV.AU
Since 1970s, N2O has increased at an
average rate of ~0.75 ppb yr–1
Agricultural soils are known to be the
major anthropogenic source of N2O.
The agricultural sector contributes 80%
of total N2O emissions of Australia.
Climate Adaptation 2014: Future Challenges WWW.DPI.NSW.GOV.AU
Cereal/oilseed crop production accounts for more than 70%
of the total N fertilizer use in Australia
Climate Adaptation 2014: Future Challenges WWW.DPI.NSW.GOV.AU
What should we do
to adapt
the climate change
Climate Adaptation 2014: Future Challenges WWW.DPI.NSW.GOV.AU
N-fertilized crops: Data have been
restricted to trials where only N
fertilizer was used.
Legume crops: Data come from
systems where either no N fertilizer
was used, or legumes were supplied
with just 5 kg fertilizer-N ha-1
Climate Adaptation 2014: Future Challenges WWW.DPI.NSW.GOV.AU
The aim is to examine whether cropping rotations with legumes as
adaptation options to climate change can reduce N2O emissions.
An alternative is to incorporate leguminous crops into
cereal cropping rotations to provide a biological source of N
Climate Adaptation 2014: Future Challenges WWW.DPI.NSW.GOV.AU
Material and method
Field experiment
CpWB: chickpea-wheat (80 kg N ha-1) -barley
CaWB: canola (80 kg N ha-1)-wheat (80 kg N ha-1)-barley (60 kg N ha-1)
Mean temperature 17.2 oC Annual rainfall 705 mm
Climate Adaptation 2014: Future Challenges WWW.DPI.NSW.GOV.AU
By using a fully automated closed
chamber monitoring system, we
tested the mitigation potential of
the legume-involved rotations at
the field scale.
Using the date from field to
validate DNDC model.
Climate scenarios (AR5 scenarios):
By using DNDC model to evaluate
the long-term effects of the legume
rotations on mitigation and
adaptation under climate change
scenarios in northern Australia.
Future simulate Observe Validate DNDC
Climate Adaptation 2014: Future Challenges WWW.DPI.NSW.GOV.AU
Climate scenarios: RCP 4.5 with radiative forcing stabilized shortly after 2100 scenarios RCP 8.5 with very high greenhouse gas emissions (adopted based on the Intergovernmental Panel on Climate Change (IPCC) fifth Assessment Report (AR5) ) Climate data of RCP 4.5 and RCP 8.5 A weather-generator statistical downscaling method (Liu and Zuo, 2012, Liu et al.,
2014) was utilized to downscale IPCC AR5 GCM (CSIRO Mk 3.6) projection under
the RCP 4.5 and RCP 8.5 scenarios to yield the daily climate data for the period of
1960-2100.
Historical climate data for the period of 1960-2013 were obtained from the SILO Patched Point Dataset and were used for two purposes: ①The data for the period of 1960-2000 were used to establish the relationship between CSIRO-Mk3.6 simulated climate and the measured historical climate for bias-correlation as described by Liu and Zuo (2012). ②The period of historical 1961-2010 were used as a baseline to run DNDC model for simulating the discrepancy of N2O emissions and grain yields under current climate.
Climate Adaptation 2014: Future Challenges WWW.DPI.NSW.GOV.AU
(Although the downscaling approach incorporates a bias-correlation, the downscaled daily climate is still needed to demonstrate agreement with site measured data)
No clear trends for precipitation Air temperature increased
Climate Adaptation 2014: Future Challenges WWW.DPI.NSW.GOV.AU
Rainfall event +Fertilization event
R2>0.95 good performance for these site-specific rotation systems
Climate Adaptation 2014: Future Challenges WWW.DPI.NSW.GOV.AU
1、Ob~Si p<0.001 2、WFPF~N2O p<0.001
WFPS→N2O Mineral N contents→N2O
WFPS>70% Most time <20 mg N kg-1 except the peaks of N2O emission
Climate Adaptation 2014: Future Challenges WWW.DPI.NSW.GOV.AU
Both the observations and simulations show less cumulative N2O emissions from the CpWB
compared to the CaWB rotation.
① greater amounts of residue N
② the high rate of canola litter incorporation and the following mineralization processes during the post-harvest fallow
season
③ the legume crop prefers to absorb the soil mineral N before it fixes atmospheric N., increased the NUE
29% 1%
0.31 kg N 0.24 kg N
<<
Climate Adaptation 2014: Future Challenges WWW.DPI.NSW.GOV.AU
The prediction errors of cumulative N2O emissions and grain yields for the two rotations were less than 10% of the observed values
(189 kg ha-1 for grain yield which was 6% of observations; 0.006 kg N ha-1 for N2O emissions which was 1% of observations).
Long-term impact of the legumes adopted in the rotation was simulated by running DNDC for 87 years
39%
74%
2%
5%
3%
12%
Climate Adaptation 2014: Future Challenges WWW.DPI.NSW.GOV.AU
Conclusions ① N2O emissions from the two rotation systems under the two climate scenarios would
gradually increase;
② the increasing rate of N2O with the CpWB rotation with legume would be much lower
than that with the CaWB rotation without legume crop (39% vs. 74% increase for CpWB
and CaWB, respectively).
③ In comparison with CaWB, CpWB decreased the yield-based N2O-N emission rate by an
average of 22% under the two RCP scenarios.
Our conclusion is that involving legume crops in the rotation
systems could be a promising strategy to mitigate N2O emissions
from the rain-fed cropping systems in the northern Australian
grain growing region.
Climate Adaptation 2014: Future Challenges WWW.DPI.NSW.GOV.AU
Acknowledgement
NSW Department of Primary Industries made the opportunity for the
senior author to visit Graham Centre for Agricultural Innovation. The
funding support from Australian Government (Department of Agricultural,
Fisheries and Forestry) and NSW Department of Primary Industries for
this work is greatly acknowledged.
Climate Adaptation 2014: Future Challenges WWW.DPI.NSW.GOV.AU
Climate Adaptation 2014: Future Challenges WWW.DPI.NSW.GOV.AU
IPCC 2013