Reduzierte Bodenbearbeitung reichert Humus und mikrobielle Biomasse oberflächlich an

When residues and organic fertilizers are not incorporated into the soil, they build a top soil layer that is enriched in soil organic matter. This is leading to a soil layer with increased biological activity, while the soil layers below, receive less inputs in form of residues or manures and show a reduction in soil organic matter and biological activity. Soils from a replicated field trial and two on-farm trials were analysed for biological soil quality 6 years after the implementation of reduced tillage (RT) as compared to plough. Whilst crop yields were slightly lower with RT, weed cover was increasing, but not to a level that would compromise yields. Soils under RT accumulated soil organic matter in the tilled top layer of 0-10 cm, while in the layer below either no change or a decrease as compared to the plough system was found. The same was true for microbial biomass, but the difference between RT and plough became more pronounced. Dehydrogenase activity was found to react most to the tillage induced changes. Accumulated soil organic matter, living and active organisms at the soil surface render soils more resistant to the weather impact