Purpose Peat-based substrates constitute the preferred media in conventional and organic nursery production. Nevertheless, in recent years, there has been a growing interest in environmental impacts associated with peat extraction that has increased with the demand of these non-renewable substrates. The re-use of organic wastes as substrate seems to be good solution to substitute commercial peat. This study evaluates date-palm peat (wastes of date-palm branches base locally known as "Kornef") as an alternative nursery substrate. Methods The research was conducted in a completely block randomized design with a linear substitution (0, 25, 50, 75 and 100%) of peat with date-palm waste peat for transplant production of lettuce (Lactuca sativa L.). Different physicochemical parameters (porosity, bulk density, pH, and CEC) of cultivation substrates were measured. The growth parameters (leaves number, leaves area, length, chlorophyll values, fresh and dry weight of seedlings) were evaluated at the end of growth period (when the seedling reached the commercial transplanting size). ResultsThe results showed that date-palm waste peat is an appropriate media for nursery production, showing similar properties with commercial peat and best plant response with 25 and 50% substitution. Conclusions In view of low cost, availability and large area of date-palm cultivation in Tunisia and over the world, it seems that peat can be replaced with substrate of date-palm wastes in the horticulture sector.Publisher's Note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

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 lycopersicumL., 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 envvironments.

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