Accounting for the legacy of soil and crop management when assessing climate change impact on crop production

Transcription

1 Accounting for the legacy of soil and crop management when assessing climate change impact on crop production Bruno Basso - Dumont B. - Shcherbak I. - Asseng S. - Bassu S. - Biernath C. - Boote K. - Cammarano D. - De Sanctis G. - Durand J.L. - Ewert F. - Gayler S. - Grace P. - Grant R. - Kent J. - Martre P. - Nendel C. - Paustian K. - Priesack E. - Ripoche D. - Ruane A. - Thorburn P. - Hatfield J. - Jones J. - Rosenzweig C. Department of Earth and Environmental Sciences and W.K. Kellogg Biological Station

2 Soil variables is less tested in crop models Model validation has been limited in agricultural systems for : Ø soil water balance (22) Ø nitrogen (13) Ø carbon (2) Basso et al., Advances in Agronomy

3 Rationale and research questions Ø Increase in temperature decreases yield Ø (Asseng et al., 2013, Bassu et al., 2013) Ø Losses of Soil Organic Carbon (SOC) and fertility decrease yield (Lal, 2004, Lal et al., 2016) Ø What is the models uncertainty per degree of temperature increase when simulating SOC and Yield in continuous mode? Ø What is the compounding effect of climate change and declines in soil organic carbon?

4 Continuous vs reinitialized runs PESW on the planting date (DOY 120) for rainfed maize. Red line shows PESW for the continuous simulation; black line shows PESW reinitialized on January 1; straight grey line shows initial PESW for the reinitialized model. SALUS runs in Nebraska. Basso et al., PLOS One

5 Accounting for management (Basso et al., PLOS One)

6 Participating Models Name Maize Wheat APSIM X ECOSYS X X SALUS X X STICS X X MONICA X X DAYCENT X NWHEAT X XNSPA X

7 Sites Maize Rio Verde, Brazil Lusignan, France Morogoro, Tanzania Ames, Iowa, USA Wheat Balcarce, Argentina Wongan Hill, Australia New Delhi, India Wageningen, Netherlands

8 Factors Factor Factor Levels Maize Wheat Site 4 sites Ѵ Ѵ Temperature ( C) -3, Baseline, +3, +6, +9 Ѵ Ѵ Tillage No-till, Convent. Tillage Ѵ Ѵ CO 2 (ppm) 360, 450, 540, 630, 720 Ѵ Ѵ N -50%, Baseline, +50% Ѵ Rain -30%, Baseline Ѵ

9 30-year continuous simulations

10 Wheat reinitialized and continuous simulation - baseline

11 Maize reinitialized and continuous simulation - baseline

12 Cumulative Bias (Yield Reinit. Yield Cont.)

13 SOC changes SOC decreases with temperature increase SOC generally decreases for wheat/maize fallow rotation IN and FR gain some SOC at 0c and -3C Wheat Maize

14 Results Relative changes in yields simulated by model ensembles for the different sites and temperature changes compared to the baseline scenario REINITIALIZED CONTINUOUS Site Temperature change -3 C +3 C +6 C +9 C AR AU IN NL Avg. wheat BR FR TZ US Avg. Maize Irrig. syst RnFd. syst Site Temperature change -3 C +3 C +6 C +9 C AR AU IN NL AvgAvg. Wheat BR FR TZ US Avg. Maize Irrig. syst RnFd. syst

15 Compounding effects of SOC losses and T increase on yield Yield differences between the two modes, normalized by the yields simulated under the baseline scenario reinitialized mode

16 SOC and Residues Variable Temperature -3 C +0 C +3 C +6 C +9 C Avg. Residues Wheat [ton ha -1 yr -1 ] Maize rainfed Maize Irrigated Wheat SOC [%] Maize rainfed Maize Irrigated

17 Results 3D response surface to temperature scenario and SOC content Avg. Annual Yield ton. ha 12 ~ f T, SOC Avg. Annual Yield ton. ha 12 = c < + c 2 T + c? SOC + T SOC è All coefficients c 0, c 1, c 2, c 3, have a significant impact on the Residues è All coefficients except c 3 (T*SOC) have an impact on the Yield

18 Conclusions With the temperature increase models on average showed: Ø increase in Soil N-NO 3 - Ø Decrease in SOC and SON It is crucial to run models in continuous mode to identify adaptation strategies Understand sources of variability that lead to model improvements