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[BACKGROUND] Despite the optimal characteristics of peat, more environmental-friendly materials are needed in the nursery sector, although these must guarantee specific quantitative and qualitative commercial standards. In the present study, we evaluated the influence of biochar and compost as peat surrogates on yield and essential oil profile of two different varieties of basil (Ocimum basilicum var. Italiano and Ocimum basilicum var. minimum). In two 50-day pot experiments, we checked the performances of biochar from pruning of urban trees and composted kitchen scraps, both mixed in different proportions with commercial peat (first experiment), and under different nitrogen (N) fertilization regimes (second experiment), in terms of plant growth and volatile compounds profile of basil., [RESULTS] Total or high substitution of peat with biochar (100% and 50% v.v.) or compost (100%) resulted in seedling death a few days from transplantation, probably because the pH and electrical conductivity of the growing media were too high. Substrates with lower substitution rates (10–20%) were underperforming in terms of plant growth and color compared to pure commercial peat during the first experiment, whereas better performances were obtained by the nitrogen-fertilized mixed substrates in the second experiment, at least for one variety. We identified a total of 12 and 16 aroma compounds of basil (mainly terpenes) in the two experiments. Partial replacement of peat did not affect basil volatile organic compounds content and composition, whereas N fertilization overall decreased the concentration of these compounds., [CONCLUSION] Our results support a moderate use of charred or composted materials as peat surrogates.

We checked the effect of biochar addition to a fertile temperate soil on plant growth and the quantity and quality of seeds of four varieties of wheat (Triticum spp., two “ancient” varieties, Verna and Senatore Cappelli, and two “modern” varieties, Bologna and Claudio) and a high oleic hybrid of sunflower (Helianthus annuus L.). Relatively novel is the qualitative investigation of the marketable product, as few are the works on this topic. We tested three different doses of biochar—1, 4, and 20 t ha−1—versus an untreated soil (“control”) in a 2-year open field trial in Central Italy, where wheat was grown the first year and sunflower the second year. Biochar addition did not change the soil characteristics save for the carbon content, which increased significantly with the highest dose of biochar. Also, we did not find any significant biochar-induced effect on plant growth and yields of both wheat and sunflower. Regarding the qualitative aspects, adding biochar to the soil implied an increase in total polyphenols in the middlings and bran of wheat and, with the highest dose of biochar, also in total proteins and in flavonoids and caffeic acid derivatives. Instead, no difference in carotenoids concentration and antiradical activity was observed in middlings or bran. As for the sunflower, no significant difference in seeds’ composition was detected at any of the biochar doses. The addition of biochar to a fertile, well-drained soil as the one we investigated is not detrimental to the quantity and quality of wheat and sunflower seeds. Rather, the concentration of some polyphenols in wheat appears to be positively affected by biochar addition.