BackgroundOrganic soilless production in containers requires substrates with appropriate physicochemical and biological properties to ensure that production is sustainable and profitable for several production cycles. The main objective of this study was to comprehensively evaluate these properties in three different mixtures of organic substrates (vermicompost [V] and coconut fibers [CF] in ratios 20V80CF, 40V60CF, 60V40CF) for four horticultural crop production cycles (PCs) using vermicompost tea (VT) as the main source of nutrients.ResultsReadily available water (25%) in the control treatment (20V80CF) was below the recommended limit, and dry bulk density (>450 g/L) surpassed the recommended limit in the 60V40CF treatment (p < 0.05). In terms of chemical properties, cations and anions in the saturated media extract decreased significantly to values below established optimal conditions. Furthermore, the substrates presented high enzymatic activity in successive production cycles (p < 0.05), including dehydrogenase (350–400 μg TFF g−1), acid phosphatase (4,700 μg p‐nitrophenol g−1 soil hr−1), and β‐glucosidase (1,200 μg p‐nitrophenol g−1 soil hr−1) activity during transformation from organic matter to inorganic compounds.ConclusionThe 40V60CF treatment presents adequate physicochemical and biological characteristics for reuse for more than four growing cycles when organic supplements are administered.

For some years now, part of society has been demanding the implementation of circular economy models and so the use of organic matter as a source of nutrients is once again taking center stage. In this scenario, the aim of this work was to implement an integrated management model for a farm and to study the influence on a celery crop of organic amendments (animal and vegetable) obtained on the farm, as opposed to inorganic fertilization. This influence was evaluated for the yield and the nutritional, organoleptic, and sanitary quality of the resulting crops. The yield and size of the marketable parts of the celery plants were greater with the inorganic treatment; however, the nutritional and sanitary quality was better in the organic treatments, while the chromatic attributes, as well as the total P and Ca, were not affected by the different fertilization treatments applied. It is therefore concluded that the organic management model is environmentally and economically sustainable.

The valorisation of vegetal waste as a source of crop nutrients constitutes a circular strategy to improve the sustainability of intensive horticultural production systems. The main goal of this study was to evaluate the effects of organic amendments derived from vegetal residues on the yield and quality of tomato. The following fertilisation treatments were carried out: fresh vegetal residues (4 kg m−1), compost (3 kg m−1), and vermicompost at two different doses (3 and 9 kg m−1), all derived from previous tomato crop vegetal residues, an organic treatment with goat manure (3 kg m−1), and a control mineral fertigation treatment. The highest yield was obtained with conventional mineral fertigation management, followed by vermicompost treatments at two different doses (3 and 9 kg m−1), with no statistical differences. The organic treatments with fresh crop residues, compost and goat manure resulted in lower yield. Regarding quality parameters, the lycopene content was higher in the mineral fertilisation and vermicompost at 3 kg m−1 treatment, while the other antioxidants measured were more concentrated in tomatoes fertilised with vermicompost treatment at 9 kg m−1 and goat manure. The plant nutrient management with vermicompost is the best circular solution, as it allows to reintegrate the residues generated in previous crop cycles into the soil, obtaining a yield equal to chemical input management and tomatoes with high nutritional quality.

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The invasion of the macroalgae Rugulopteryx okamurae is causing several environmental and economic problems along Spanish Mediterranean coasts. The use of composts based on R. okamurae as a peat alternative in nursery production could be a valid alternative for the exploitation of this organic material. The present study evaluated three different composts as peat substitutes in potting media to grow tomato seedlings: compost of R. okamurae, compost of green horticultural residues (two-thirds) and R. okamurae (one-third), compost of garden pruning residues (two-thirds) and R. okamurae (one-third). Each compost was used to formulate two different substrates to reduce the use of peat (40% compost, 40% peat, 20% perlite) or entirely substitute it (80% compost, 20% perlite), using a control treatment with 80% peat and 20% perlite. Only the control treatment received mineral fertigation during the trial. The results showed that the high initial electrical conductivity and ion concentration were remarkably reduced thanks to the fast leaching of salt that occurred with customary irrigation. Generally, compost-based treatments allowed us to obtain tomato seedlings with satisfactory morphological parameters. The substrates that contained 40% compost of R. okamurae or a compost of garden pruning residues and R. okamurae led to the best results in term of seedling parameters. It is therefore concluded that composts based on R. okamuare could be used as a seedling growing medium for the valorization of algae.