Miriam Muñoz -Rojas , Luca Doro, Luigi Ledda , and Rosa Francaviglia

1. Application of CarboSOIL model to predict the effects of climate change on soil organic carbon stocks in agro-silvo-pastoral Mediterranean management systems Miriam Muñoz-Rojas , Luca Doro, Luigi Ledda, and Rosa Francaviglia

2. CarboSOIL: a land evaluation tool for soil C assessment CarboSOIL, a new component of the Agroecological Decision Support System MicroLEIS

3. CarboSOIL: a land evaluation tool for soil C assessment Climate regulation Soil structure Soil fertility Water holding capacity Infiltration capacity Water use efficiency Soil biological health

4. CarboSOIL: a land evaluation tool for soil C assessment Climate Winter Temperature Summer temperature Annual Rainfall Soil N, pH, CEC Texture Bulk density Water Holding Capacity CarboSOIL Site Elevation Slope Land use 15 land use types

5. CarboSOIL: a land evaluation tool for soil C assessment LAND USE CLIMATE SITE SOIL INPUT FACTORS TJJA PPT ELEV SLOP SERO DRAI FCAP SAND CLAY PHWA CEXC NITRO BULK LULC CarboSOIL model diagram TDJF Mineralisation Incorporation of residues Aereation Nutrientavailability Biologicalactivity SOIL PROCESSES OUTPUTS SOIL ORGANIC CARBON 0-25, 25-50, 50-75 cm Respiration Accumulation / loss Source: Muñoz-Rojas, 2012

6. CarboSOIL: a land evaluation tool for soil C assessment CarboSOILstructure y = a+ b1x1+b2x2+b3x3+ ---+bnxn y= SOC ; a= Intercept; b= variables; x= coefficients

7. Study area North-eastern Sardinia (Italy) 40°46’N, 9°10’E • Mean altitude -285 m • Climate- warm temperate with dry and hot summer. • Mean annual rainfall of 623 mm (range 367–811) • Mean annual temperature 15.0°C (13.8–16.4) • Soil type - HaplicEndolepticCambisols, Dystric (WRB) • Potential native vegetation - Cork oak forest (Quercussuber L.), converted to managed land with pastures and vineyards in recent years

8. Study area Land use transformation • Six land uses with different levels of cropping intensification were compared: • Tilled vineyards (TV) • No-tilled grassed vineyards (GV) • Hay crop (HC): oats, Italian ryegrass and annual clovers or vetch for 5 years and intercropped by spontaneous herbaceous vegetation in the 6th year • Pasture (PA): 5 years of spontaneous herbaceous vegetation, and 1 year of intercropping with oats, Italian ryegrass and annual clovers or vetch cultivated as a hay crop • Cork oak forest (CO) • Semi-natural systems (SN): natural re-vegetation of former vineyards (scrublands, Mediterranean maquis and Helichrysum meadows)

9. Study area Land use transformation From left to right clockwise: no-tilled grassed vineyard (GV), grazed hay crop under oats land cover (HC), semi-natural systems with scrubs and Mediterranean maquis (SN), grazed pasture with spontaneous vegetation (PA).

10. CarboSOIL application in agro-silvo-pastoral Mediterranean management systems

11. CarboSOIL application in agro-silvo-pastoral Mediterranean management systems Input data: variables description and sources

12. CarboSOIL application in agro-silvo-pastoral Mediterranean management systems Input data: climate change scenarios

13. CarboSOIL application in agro-silvo-pastoral Mediterranean management systems Assessment of the model performance and comparison between measured and simulated values where Oi and Si are observed and simulated SOC at ith value, Ō is the mean of the observed data and n is the number of the paired values. The lowest possible value of RMSE is zero, indicating that there is no difference between simulated and observed data. EF compares simulations and observations on an average level, and can range from - to 1, with the best performance at EF=1.

14. CarboSOIL application in agro-silvo-pastoral Mediterranean management systems 0-25 cm measured SD=14.12 25-50 cm measured SD=19.53 Regression coefficients are significant at p<0.001 and R2 are high, the standard deviation of the measured values is higher than RMSE, and EF is very close to the optimum value. 50-75 cm measured SD=11.09

15. CarboSOIL application in agro-silvo-pastoral Mediterranean management systems CarboSOIL model predicted an overall increase of SOC stocks in the 2020 climate scenarios in all the soil sections, with the higher increases in the 50-75 cm section, and the smaller in the 25-50 cm soil section.

16. CarboSOIL application in agro-silvo-pastoral Mediterranean management systems A SOC decreaseis instead expected in the 2050 and 2080 scenarios in the 25-50 cm soil section, more marked in the vineyards in comparison with the other land uses.

17. CarboSOIL application in agro-silvo-pastoral Mediterranean management systems Oppositely, SOC increases are still expected in the 0-25 cm section and to a more extent in the 50-75 cm section, particularly evident in the vineyards.

18. Conclusions • The model CarboSOIL has proved its ability to predict SOC stocks at different soil depths under different climate change scenarios. • Climate change will have a negative impact on SOC stocks in the soil section 25-50 cm, in particular in a long term (2050 and 2080). • Important decreases of SOC stocks were found in vineyards. • The methodology developed in this research might be easily applied to other Mediterranean areas with available data on climate, site, soil and land use.

19. Thank you! Miriam Muñoz-Rojas , Luca Doro, Luigi Ledda, and Rosa Francaviglia