Roller-Crimping As An Alternative To Incorporation Of Agro-Ecological Service Crops Changes Nitrogen Dynamics In Organic Cabbage Production Under Northern And Western European Conditions

Summary

Agro-ecological service crops (ASCs) are used to improve organic vegetable production in terms of weed suppression, nitrogen (N) recycling, or addition of N through symbiotic N2 fixation by legumes. Full incorporation (FI) of ASCs is commonly conducted to terminate ASCs, but alternative termination can be obtained by roller-crimping (RC) in reduced tillage systems. Field experiments were conducted in Estonia, Denmark, and at three locations in Belgium during two growing seasons (autumn 2015-2017) to investigate the effect of ASC termination method (FI and RC) and ASC species (pea, pea/cereal mixtures and cereals), compared with a bare soil control, on soil mineral N content, cabbage yield and N accumulation. Cabbage yield and N accumulation were reduced under RC compared to BS and FI in a majority of cases mainly due to reduced soil mineral N availability, in some cases owing to a later ASC termination time. Furthermore, slower mineralisation of soil organic matter and ASCs at the soil surface contributed to the yield reduction under RC as compared with FI. Cabbage yield could be maintained under RC at standard fertilisation rate following pea ASC in Denmark. The RC system needs further investigation to improve N availability to the succeeding crop before it can be implemented in organic vegetable production.