Effect of soil organic matter management on soil characteristics, potato yield and potato disease in an intensive potato growing system (MERMOLD) NORSØK Report Vol. 7 (2022)

The MERMOLD study (2019–2022) evaluated whether cover crops and single applications of organic amendments (biochar+liquid digestate, solid digestate, farmyard manure) can increase soil organic matter (SOM) and affect potato yield and storage diseases in intensive potato systems. A field experiment and laboratory incubation were used to measure changes in SOM fractions, potato yields, disease severity and CO2 emissions. Results showed increased SOM after a single application, notably with farmyard manure and biochar+liquid digestate; cover crops increased yields in 2021 and reduced post-harvest disease severity, while organic amendments had limited effects on yield but tended to improve marketable yield after storage.