Biokolets påverkan på markens organiska material - Kan gödsling med biokol bidra till en kolinlagring i marken?

Sammanfattning: Here I present a conceptual synthesis of the processes governing soil carbon in the event of biochar application. Biochar is a product of a controlled pyrolysis process and is known for its physical, chemical and adsorptive properties. It has been speculated to be a tool for sequestering carbon in soil to offset greenhouse gas emissions, and as a soil amendment. The study is done in collaboration with the company Ecobalans from Lund, and is a part of the environmental system analysis in a research and development project concerning sludge processing through pyrolysis. The aim of this review is to investigate if biochar application to soil can contribute to carbon sequestration in soil, by looking at the processes affecting the soil organic matter (SOM). Preforming a scientific review presenting the results with a causal loop diagram does this. The recalcitrance fractions of the soils organic carbon initially enhances with biochar application, but an enhanced decomposition of the labile fraction has also been reported. There is causality with improved crop yield. There are suggestions that the biochar stays safe from decomposition by forming aggregates and organo-mineral complexes over time. This review shows that effects of biochar on SOM cannot be simplified as they are biochar-specific (feedstock and treatment) and site-specific (soil and climate) but can be qualitatively calculated on in the conceptual model presented in this study.