Effect of vermicompost soil additive on growth performance, physiological and biochemical responses of tomato plants (Solanum lycopersicum L. var. Firenze) to salt stress

Abstract

Vermicomposting is increasing used to process food, sewage and other organic wastes through the breakdown by earthworms. Vermicompost addition to soils can improve plant growth through increasing the accessability of nutrients and lowering levels of contaminants found in other compost products. This study examins the effect of vermicompost on salinity tolerance in tomato plants (Solanum lycopersicum L., var. Firenze) via greenhouse pot experiments. Plants were grown on 4 substrates designated by letter identifiers: A control, “T” with 100% organic soil; a vermicompost treatment “Vc” was 80% organic soil + 20% Vermicompost; a compost treatment “C” was 80% organic soil + 20% Compost; and a mixture treatment “M” was 80% organic soil + 10% Vermicompost+ 10% Compost. The four treatment groups were exposed to 3 NaCl concentrations (0, 50 and 150 mM); the experimenta; design within the greenhouse was complete randomized block. The plants’ response to salinity stress was evaluated through morphological (shoot length, stem diameter, leaves number, root length, shoot and root fresh and dry weight), physiological (Chla, Chlb and Carotenoid) and biochemical (malondialdehyde (MDA) and catalase (CAT)) parameters. All measured parameters were significantly different between the four soil treatments. Plants grown on Vc substrate showed an improved growth and a better resistance to salinity stress. Analyzed parameters were positively influenced by the contribution of the organic matter (Vermicompost, compost and a mixture of the two) which plays a role in the slow, consistent release of mineral elements and provides soluble nutrients to reduce abiotic stresses. In conclusion, vermicompost could be a relevant method for reducing salt stress on tomato plants growth, addressing the challenges of growing food crops in drier, more saline contaminated environments.