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

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. © 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Application of biostimulant products and biological control agents in sustainable viticulture: A review.

Current and continuing climate change in the Anthropocene epoch requires sustainable agricultural practices. Additionally, due to changing consumer preferences, organic approaches to cultivation are gaining popularity. The global market for organic grapes, grape products, and wine is growing. Biostimulant and biocontrol products are often applied in organic vineyards and can reduce the synthetic fertilizer, pesticide, and fungicide requirements of a vineyard. Plant growth promotion following application is also observed under a variety of challenging conditions associated with global warming. This paper reviews different groups of biostimulants and their effects on viticulture, including microorganisms, protein hydrolysates, humic acids, pyrogenic materials, and seaweed extracts. Of special interest are biostimulants with utility in protecting plants against the effects of climate change, including drought and heat stress. While many beneficial effects have been reported following the application of these materials, most studies lack a mechanistic explanation, and important parameters are often undefined (e.g., soil characteristics and nutrient availability). We recommend an increased study of the underlying mechanisms of these products to enable the selection of proper biostimulants, application methods, and dosage in viticulture. A detailed understanding of processes dictating beneficial effects in vineyards following application may allow for biostimulants with increased efficacy, uptake, and sustainability.

Recycling pyrolyzed organic waste from plant nurseries, rice production and shrimp industry as peat substitute in potting substrates.

Organic waste from greens of tomato plants, gardening substrate, rice husks and shrimp-derived chitin were pyrolyzed at 400 °C and 500 °C for 3 h, with the aim to elucidate the feasibility of using such products as replacement of peat in soilless gardening substrates. Characterization of the carbonized organic matter (COM) and the gardening substrate indicated that neither the peat nor the COMs provided the recommended levels of nutrients for the cultivation of tomato plants, although improvements could be obtained using COM/substrate mixtures. The toxicity thresholds for Zn were exceeded significantly by the COMs of the tomato greens and high boron levels were found for all the COMs except for those derived from chitin. In a 40-days pot experiment, germination and development of tomato seeds and plants (Solanum lycopersicum L.) were tested on COM/peat mixtures at 30%, 60% and 100% COM substitution rate. The lack of seed germination on the mixtures with COM from tomato greens is best explained with the high salinity of the COM. Best plant growth was obtained with COM from chitin at 60%, most likely because its high N content satisfied best the N-needs of the growing tomato plants without increasing the pH of the growing media. Moreover, an increase of water retention was evidenced for COM/substrate mixtures. Although the use of COM from chitin and rice husks showed promising results, the proposed recycling of organic waste from agriculture or fishery as soilless gardening substrate requires the development of formulations of COM/peat/and added nutrients with ready-to-use characteristics to increase its feasibility.

Activity of Trichoderma asperellum Strain ICC 012 and Trichoderma gamsii Strain ICC 080 Toward Diseases of Esca Complex and Associated Pathogens.

Grapevine trunk diseases are widespread in all grape-growing countries. The diseases included in the Esca complex of diseases are particularly common in European vineyards. Their distinctive foliar symptoms are well known to be associated not only with losses in quantity, as with all grapevine wood diseases, but also with losses in the quality of the crop. Protection of pruning wounds is known to reduce infections in artificial inoculations and, to some extent, reduce the external leaf symptoms. The application of biological control agents in the field is typically started at the first appearance of symptoms. In this article, the two strains belonging to two different species, Trichoderma asperellum ICC 012 and T. gamsii ICC 080, which are present in a commercial formulation, were tested in vitro, in vivo in artificial inoculation, and in the field in long-term experiments where the wounds on four young asymptomatic vineyards were protected since 1 or 2 years after planting. The in vitro trials highlighted the different temperature requirements of the two strains, the direct mycoparasitizing activity of T. asperellum, and the indirect activity shown by both Trichoderma strains. The in vivo trials confirmed the ability of the two strains to reduce the colonization following artificial inoculations with the high, unnatural concentration of spores used in artificial infections, even if with variable efficacy, and with long persistence as they could be reisolated 7 months post-application. The preventive applications carried out over 9 years showed a very high reduction in symptom development in the treated vines, on annual and cumulated incidence and on the death of vines, with disease reduction varying from 66 to almost 90%. Early and annual application of protection to the pruning wounds appears to be the best method for reducing damages caused by grapevine leaf stripe disease (a disease of the Esca complex of diseases). Trichoderma appears to offer an efficient, environmentally friendly, and long-lasting protection in the presence of a natural inoculum concentration.