Options for increased soil carbon storage and water holding capacity through sustainable agriculture and forestry: modelling results from showcase regions in Austria

Abstract:

Sustainable agriculture and forestry is an important topic under climate change. This is a potential route for increasing long-term soil and biomass carbon storage, soil water retention capacity and for reducing water and wind erosion risks. This study uses the Styrian Raab and Enns catchment regions in Southeastern Austria as showcase regions for exploring sustainable whole-system options for climate change adaptation and mitigation under increased hot-dry conditions in agriculture and forestry. Based on dense data of the WegenerNet observing network and further hydrometeorological data, combined with hydrological modelling (WaSiM), the current hydrological disturbance potential in the Southeastern Austria focus regions is assessed. Furthermore, downscaled IPCC climate change scenarios are used for future projections and the results are evaluated for increasing heat and drought risks. This work provides the hydrological context for modelling the soil water and carbon storage enhancement options that farming, forestry and land-use practices might apply. A first key study aspect in this context is the sustainable potential of bioenergy crops. Using the local-scale WegenerNet data combined with Harmonized World Soil Database (HWSD) soil data, potential yields for bioenergy from lignocellulosic biomass (forest and Miscanthus, willow and poplar) is modelled using MiscanFor, SalixFor, PopFor and DAYCENT models for representative local areas in the showcase regions. Using DAYCENT biogeochemical modelling with different agricultural, forest management, and land use practices under climate change, sustainable system options under different future climate change scenarios are developed. These results will be used in turn to develop whole-system options, namely to jointly achieve increase of soil carbon and robustness of soil water retention capacity, increase of soil quality, reduction of soil erosion and degradation, reduced compaction, stabilisation of slopes, sustainability and resilience in the soil as well as the agricultural and forest production system. Sustainable whole-system options for farmers and forest managers are the major study focus and will supply data for local estimates in the chosen representative areas in the showcase regions as well as for upscaling to country level.