PRELIMINARY STUDY ON THE INFLUENCE OF THE USE OF VERMICOMPOST AS A CULTURE SUBSTRATE ON THE QUALITY OF LETTUCE SEEDLINGS (Lactuca sativa L.)

The experiment was carried out at the University of Agronomic Sciences and Veterinary Medicine of Bucharest, Faculty of Horticulture under laboratory conditions in 2020. During the COVID 19 pandemic, it took place in the university greenhouse, from the end of October until the end of November 2020. The biological material was represented by Red Oak lettuce cultivar, vermicompost (also known as vermicast), peat, zeolite and perlite. The paper aimed to present the benefices of using vermicompost in reducing nutrient solution and a higher yield. We tested 13 variants with 3 repetition each and used vermicompost in different percent as substrate such as 0%, 25%, 50% and 100% of pot volume. The vermicompost was produced by California Red Wigglers from converting two types of precomposted manure, horse and cattle over the period of 26 weeks. The vermicompost has a neutral PH 6.8-7.2 and does not burn the plant. The lettuce from variants where vermicompost was added, had a lower nutrient solution intake, this being an economic effect to reduce water consumption.

Using the Halophyte Crithmum maritimum in Green Roofs for Sustainable Urban Horticulture: Effect of Substrate and Nutrient Content Analysis including Potentially Toxic Elements

The effect of substrate type and cultivation site in the urban fabric on growth, nutrient content and potentially toxic element (PTE) accumulation in tissues of the halophyte Crithmum maritimum was studied. Plantlets were cultivated for twelve months in containers with a green-roof infrastructure fitted and placed either on an urban second-floor roof or on ground level by the side of a moderate-traffic street. Two substrate types were used;one comprising grape marc compost, perlite and pumice (3:3:4, v/v) and one composed of grape marc compost, perlite, pumice and soil (3:3:2:2, v/v), with 10 cm depth. Plants grew well on both sites, although aboveground growth parameters and nutrient content in leaves were greater at street level. Both cultivation site and substrate type affected heavy-metal accumulation in plant tissues. Cu, Ni and Fe concentrations in leaves and Pb in roots were higher in street-level-grown plants compared to the roof-grown plants, and concentrations of Cu and Mn in leaves and Fe in both leaves and roots were lower in the soilless substrate compared to the soil-substrate, making the soilless type preferable in the interest of both safer produce for human consumption and lower construction weight in the case of green-roof cultivation.