Posidonia-Based Compost and Dredged Sediment in Growing Media Improve Tolerance and Nutrient Uptake in Ornamental Plants

Abstract

Because of the high costs and environmental impacts of peat and chemical fertilizers, the search for sustainable alternatives is increasing. Posidonia-based compost (C) has been widely tested as a growing media, while the combination with decontaminated dredged sediments (S) has only recently been studied. Moreover, little information is available on the relationship between plants and growing media. In this work, the suitability of growing media (CS) composed of 100% C, 70% C + 30% S and 30% C + 70% S were investigated compared to peat, for ornamental plants (Elaeagnus macrophylla, Photinia × fraseri and Viburnum tinus). Plant growth, physiological, nutritional and antioxidant responses were also investigated. The CS were compliant with current legislation on growing media. The Cu (+60%; +70%), Mg (+11%; +23%) and Ca (+66%; +72%) concentrations were higher in CS with 30% and 70% of S, respectively, than peat. The plants growing in CS had lower antioxidant activities than those on peat, suggesting a better plant tolerance to abiotic stress. In conclusion, the use of CS growing media, especially those with 30% and 70% of S, can be a valuable strategy to replace peat and reduce the application of fertilizers.

The Decomposition Dynamics and Substrate Component Potential of Biomass from the Seagrass Posidonia oceanica (L.) Delile

“…For S. chamaecyparissus, a concentration-dependent trend was observed in fresh P. oceanica, where growth diminished with increasing percentages of P. oceanica. In a study on the growth of ornamental species by [36], a substrate composed of P. oceanica compost-based and decontaminated dredged sediments was studied, recommending a utilization concentration ranging from 30% to 70% of P. oceanica. Our findings align with such recommendations, proposing an application ratio ranging from 10% to 50% for these species.…”

Co-Composting of Green Waste and Dredged Sediments Can Reduce the Environmental Impact of the Potted Nursery without Affecting Plant Growth

“…In recent years, raw or composted waste by-products, such as mushroom compost [2], paper mill sludge [2,16], almond shell waste [17], and coir (or coconut fiber) [18,19] were tested as a total or partial alternative to peat moss in the growing media, with variable results in terms of growth and quality of plant production. Amongst them, one of the most interesting waste by-products is represented by dredged marine and river sediments [20][21][22][23][24]. Although the micro-and macro-nutrient contents of dredged sediments make these matrices a good candidate as peat-free growing media, the presence of high levels of hydrocarbons and heavy metals limits their recycling in agriculture [22].…”