Effects of biochar and compost addition in potting substrates on growth and volatile compounds profile of basil (Ocimum basilicum L.)

Abstract

BackgroundDespite the optimal characteristics of peat, more environmental‐friendly materials are needed in the nursery sector, which however must guarantee specific quantitative and qualitative commercial standards. In this work, 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 O. basilicum var. minimum). In two 50‐days 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 N fertilization regimes (second experiment), in terms of plant growth and volatile compounds profile of basil.ResultsTotal or high substitution of peat with biochar (100% and 50% v.v.) or compost (100%) resulted in seedlings death after few days from transplantation, probably because of the growing media's too high pH and electrical conductivity. Substrates with lower substitution rates (10‐20%) were underperforming in term of plant growth and color compared to pure commercial peat during the first experiment, while 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, while N fertilization overall decreased the concentration of these compounds.ConclusionOur results support a moderate use of charred or composted materials as peat surrogates.This article is protected by copyright. All rights reserved.