- 1University of Aveiro, Centre for Environmental and Marine Studies, Department of Environment and Planning, Aveiro, Portugal (frankverheijen@gmail.com)
- 2Marine, Environment and Technology Centre (MARETEC), Associação do Instituto Superior Técnico para a Investigação e o Desenvolvimento (IST-ID), LARSyS, Instituto Superior Técnico, University of Lisbon, 1049-001 Lisbon, & Terraprima, Portugal
Climate change models indicate that pastoral land use in many parts of Iberia will no longer be feasible from 2050 due to rainfall decreases and desertification, thereby negatively affecting soil functioning, food security and rural livelihoods. Amending agricultural soils with biochar (carbon-based product of biomass pyrolysis) has been shown to potentially increase crop yield, mainly by improving soil pH, soil structure, water storage and exchange. The aim of this study was to quantify how biochar may alter the soil sponge function under current (100% rainfall) and future (50% rainfall.
The collaborative work between ongoing projects SOILCOMBAT, POLLINATE and TRUESOIL, aims to sustainably engineer the soil-water regulation function of Portuguese pasture soils, while minimizing detrimental effects on other soil quality parameters through the use of biochar for soil amendment. Our approach was a random block design field-trial in a real-world scenario at the Quinta da França farm (Terraprima, Portugal), a non-irrigated sown biodiverse pasture on a dystric Cambisol. The four treatments are: control 100% rainfall; control 50% rainfall; biochar (3% gravimetric) 100% rainfall; biochar (3% gravimetric) 50% rainfall; N=20). Biochar-amendment-treatments were applied at 0-20 cm depth keeping the 20-60 cm depth unaltered. It is five times replicated. Plots were equipped with soil climate sensors (volumetric moisture and temperature) recording at six depths, namely -5, -15, -25, -25, -45 & -55 cm depth (N=120).
The first 2 years of the on-going field trial at Quinta da França showed that for the treated 0-20 cm depth with 50% rainfall, the biochar plots kept 15% more moisture than the control ones, while for 100% rainfall conditions, biochar plots kept 23% more moisture. The results for deeper soil water storage (20-60 cm depth) showed that for the 50% rainfall, the biochar plots have 24% less moisture than the control ones, while for natural rainfall conditions, biochar plots have 19% less moisture than the control ones. This could indicate that the 0-20 cm depth biochar-amended soil layer, keep more water in surface (0-20 cm depth) than non-amended surface soil. Seasonal effects will be explored further.
We conclude that biochar amendments improve the soil-water regulation functions of this pasture. The results are expected to contribute to the UN Sustainable Development Goals (SDG) #13 and #15, namely sustainable food production and climate adaptation of pastoral ecosystems, while combating desertification.
Acknowledgements
We acknowledge the Portuguese Foundation for Science and Technology FCT/MCTES for the funding of CESAM (UIDP/50017/2020+UIDB/50017/2020+LA/P/0094/2020) through national funds, as well as of projects SOILCOMBAT (https://doi.org/10.54499/PTDC/EAM-AMB/0474/2020), POLLINATE (https://doi.org/10.54499/PTDC/EAM-AMB/1509/2021), and of authors F. Verheijen (https://doi.org/10.54499/CEECIND/02509/2018/CP1559/CT0004), A.C. Bastos (art. 23º DL57/2016 of 29 Aug amended by DL 57/2017 of 19 July, OE), P. Quinteiro (CEEC/00143/2017), B. Gholamahmadi’s (PhD grant2020.04610.BD), L Simões (PhD grant 2022.09866.BD). We also acknowledge the European Commission Joint Programme SOIL for the funding of project TRUESOIL (https://doi.org/10.54499/EJPSoils/0001/2021) and the La Caixa Foundation in collaboration with CESAM for the funding of A. Jelinčić(LCF/BQ/DI22/11940011).
How to cite: Verheijen, F. G. A., Ana Catarina, B., Zahra, K., Behrouz, G., Marjan, J., Isabel, C., Liliana, S., Antun, J., Vasco, S., Patricia, S., Paula, Q., Tiago, D., and Oscar, G.-P.: Biochar impact on the soil sponge function in sown biodiverse pastures: a 2-year whole soil profile monitoring study under 100% and 50% rainfall, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-18882, https://doi.org/10.5194/egusphere-egu25-18882, 2025.
