Biowaste versus fossil sourced auxiliaries for plant cultivation: The Lantana case study

Soluble bio-based substances (SBS) were isolated from the anaerobic digestate of the organic humid fraction of urban waste and from the compost obtained from a mix of digestate, gardening residues and sewage sludge. These were compared with a commercial Leonardite-based product for their effects on the growth and productivity of two Lantana species. The SBS were found more powerful than the Leonardite-based product in enhancing plant photosynthesis, growth and aesthetic effect, improving flower quality, and optimizing water use efficiency. Enhancement factors of plant performance indicators by SBS ranged from 1.2 to 3.3 relatively to the control plants, and from 1.3 to 2.4 relatively to plants treated with the commercial Leonardite product at equal applied dose. The results are in line with findings published for other case studies performed with horticultural and ornamental plants. They confirm that municipal biowaste is a viable feedstock to obtain specialty chemicals that can efficiently replace fossil sourced products in agriculture. Options for further development work are discussed.