Cover crops as a part of organic greenhouse rotation: Implication on soil arthropods dynamics

Soil arthropods have been recognized as indicators of habitat quality and diversity in open field organic systems, while in organic greenhouses (OG) research is still rather limited. Conservation and promotion of arthropods diversity are often unrelated to the identity of the components that provide it like cover crops (CC). CC may enhance arthropods diversity and provide wide range of ecological services (e.g. shelter, soil temperature moderation). However, the use of the CC in OG is not a widespread practice because farmers aim to produce cash crops for the market during the whole year. The present study aims to investigate the soil arthropods dynamics during CC growth cycle and following cucumber cultivation within a rotation plan in OG under Mediterranean conditions. Three organic farming systems were evaluated in term of soil arthropods dynamics and abundance: i) a simplified organic production system based on organic commercial fertilizers (SUBST); ii) organic production system based on animal manure amendment and cover crops (AGROMAN), and iii) organic production system based on green manuring of cover crops and on-farm compost amendment (AGROCOM). Assessment was based on pitfall traps monitoring and classification of individuals in macrogroups. Spiders, rove beetles and isopods were more abundant in CC treatments, while other groups did not differ significantly among systems. Cucumber cultivation revealed different patterns, with more uniform results among the systems, except for AGROMAN. Results show that cover crops influenced soil arthropod diversity and their suitability to be used as bioindicators of ecological sustainability.