Reduced tillage in organic farming Lessons from the TILMAN-ORG project and beyond

Summary

Reduced tillage can lead to improvements in soil health and enhance ecosystem services including carbon sequestration, reducing soil erosion, improving soil fertility and biodiversity, whilst reducing CO2 and N2O emissions from soils and decreasing energy usage. However, some consider it incompatible with organic farming stemming from concerns around weed control, nutrient availability, and ley incorporation, as well as insufficient equipment and knowledge to make the system work. Organic Research Centre (ORC) took part in the "Reduced tillage and green manures for sustainable organic cropping systems – TILMAN-ORG" project where these issues were investigated.
The results of this project showed that organic farmers can consider reduced tillage through a pragmatic site-specific approach: they can strategically employ occasional shallow inversion tillage or even shallow non-inversion tillage to realise some of the benefits of reduced tillage without significant yield loss. Specifically, the field trials conducted by ORC showed shifts in the weed communities, improvements in crop establishment and only moderate effects on crop yield over three cropping cycles.
Further research and development needs that were identified related to synchronisation of nutrient supply and demand, machinery improvements and adaptation of farm-specific reduced tillage systems to keep weeds controlled in the long-term. ORC is currently exploring combining reduced tillage with green manures, to improve nitrogen provision and weed control as a promising option for UK arable cropping systems. Adopting living mulches, i.e., cover crops grown simultaneously with the main cash crop, can potentially enable further reductions in tillage, or even organic no-till systems.