Yield, product quality and energy use in organic vegetable living mulch cropping systems: research evidence and farmers’ perception

The effects of living mulch (LM) introduction and management strategies on cash crop yield, product quality and energy use were studied in a wide range of European vegetable cropping systems, climatic and soil conditions, as well as species of LM grown as agro-ecological service crops. Nine field experiments were carried out in research stations and commercial farms located in Denmark, Germany, Italy and Slovenia. Farmers’ perception of the feasibility and applicability of the LM technique was also assessed. The results demonstrated that the LM systems with a substitutive design can be effectively implemented in vegetable production if the value of the ecological services (positive externalities) delivered by LM can counterbalance the yield loss due to the cash crop density reduction. The crop density of the system and the length of the period in which the LM and cash crop coexist are oppositely related both for competition and yield. Moreover, if an additive design is used, the LM should be sown several weeks after the cash crop planting. Overall, different cash crop genotypes (i.e., open pollinated/local cultivars in comparison with the hybrids) performed similarly. Use of human labor (HL) and fossil fuel (FF) energy slightly increased in LM systems (7%), and there was a shift in the proportion of FF and human energy consumption. The farmers’ acceptance of the LM techniques was quite high (75% of the interviewed sample), even though their critical considerations about yield quality and quantity need consideration in future research and practical implementation of LM systems.