Inspiring diversified systems for organic and fresh vegetables produced under shelters

Trial location and duration

Location: France, Alénya (42,63765°N, 2,971884°E; 8,7m alt.) INRAE Agroecological vegetable systems experimental facility

Trial duration: October 2018 to September 2022.

Objectives and research question

At the field scale, crop diversification is a strategic practice to combine with other agroecological practices. Growing two or more cash crops on the same land in the same year is typical of market gardening systems, especially under shelters in the Mediterranean context. However, even though vegetable farms may be diverse, at field level crop sequences can have little diversity and few periods with cover crops. Intercropping and mixtures of species in cover or cash crops are seldom implemented.

We hypothesized that introducing a higher level of diversification in time and space at the field level is useful to sustain production and to mitigate risks associated with climate, pest and disease, and economics. We also hypothesized that it can prevent soil degradation and limit pest and disease damage on crops. Our experiment aims to design, assess and bring actionable knowledge on three different pathways for implementing diversification compared to a poorly diversified system focused on lettuce production. 

Experimental design

The low-diversity reference system (figure 4) was compared to three diversified systems: MODIV (figure 4) is a medium diversified system with a more diversified crop sequence than the reference (REF). The DIVBANDE and DIVMIX (figure 5) systems are highly diversified with long crop rotations and with continuous intercropping of 3 species under the tunnel. DIVBANDE uses strip intercropping where strips can be independently managed from one to the other. DIVMIX was inspired by mixed intercropping, organising plants into small patches in the vicinity of other plants while relying on common crop management for the 3 species. All four systems were under organic management from October 2018 to September 2022 in loamy-sandy soil. Each system was implemented under only one 400m² unheated plastic walk-in tunnel.