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Soil management principles in climate-smart conservation <BR>agriculture to halt and reverse land degradation (Communication session)

EUROSOIL2020CONT-1897

MANAGEMENT OPTIONS, POTENTIAL AND LIMITS FOR CARBON SEQUESTRATION IN AUSTRIAN SOILS

Heide Spiegel^{* 1}, Anna Wawra¹, Julia Miloczki¹, Taru Sandén¹, Andreas Bohner², Robert Jandl³, Ina Meyer⁴, Sigbert Huber⁵, Eugenio Diaz-Pines⁶, Sophie Zechmeister-Boltenstern⁶

¹Department for Soil Health and Plant Nutrition, Austrian Agency for Health and Food Safety - AGES, Vienna, ²Agricultural Research and Education Centre (AREC) Raumberg-Gumpenstein, ³Austrian Research Centre for Forests (BFW), ⁴Austrian Institute of Economic Research (WIFO), ⁵Environment Agency Austria, ⁶University of Natural Resources and Applied Life Sciences, Vienna (BOKU), Austria

Content: Introduction

Soil and climate change are closely interlinked. Soil is the largest terrestrial carbon pool and contains two to three times as much carbon as the atmosphere. Historical land-use changes - especially from grasslands and forests to agricultural soils - and management practices have provoked a significant decrease in soil organic carbon (SOC) stocks, thus leading to enhanced carbon dioxide (CO₂) emissions to the atmosphere. In order to combat climate change, a reduction in atmospheric CO₂ concentrations is required, which can be achieved by reducing CO₂ emissions and increasing carbon sinks. At the UN Climate Change Conference (COP21) in Paris (2015), the French Minister of Agriculture launched the 4-per-mille initiative. This initiative aims to increase soil organic carbon (SOC) stocks by 0.4 percent per year through optimised land and soil management. The Austrian project, CASAS (Carbon Sequestration in Austrian Soils), which started in September 2019, will assess which soil management practices have the potential to achieve the desired effects. Novel data from long-term field experiments on arable lands as well as on grasslands and forests will be evaluated and historical data from soil monitoring systems reassessed.

Methods

Soil samples will be taken from existing long-term experiments (arable land, grassland and forest) and analysed for parameters relevant for the storage of organic carbon in the soil (e.g. concentration of soil organic carbon, dry bulk density, total nitrogen, iron and aluminum (hydr)oxides, pH). Taking into account pedoclimatic factors (soil type, topography, temperature, precipitation) and management, the long-term carbon storage potential for different land management systems will be determined. On the basis of the scientific data, the project will also quantify the direct costs associated with the land and soil management practices necessary to achieve the 4-per-mille target for Austria. Furthermore, the associated indirect and induced economic effects will be evaluated by means of a macroeconomic model for Austria and a long-term soil management scenario including measures and instruments for their implementation.

Results

Available results of long-term field trials on arable land have shown that the organic carbon content of the soil is highest after many years of organic fertilisation (e.g. with different types of compost, manure), incorporation of crop residues and a reduction in tillage (frequency, depth). With optimised management, the organic carbon content of the topsoil can at least be maintained on most of the sites studied. Covering the soil for as long as possible (e.g. catch crops, field forage plants, grassland) also promotes carbon storage. However, data shows that all these measures must be continued over time, otherwise the stored organic carbon can be released again quickly (e.g. after grassland conversion). Furthermore, we will evaluate the potential effects of SOC sequestration actions on the emissions of non-CO₂ greenhouse gases (methane and nitrous oxide).

Disclosure of Interest: None Declared

Keywords: agricultural management practices, Long-term field experiments, soil organic carbon