Effect of hydro-compacting organic mulch on weed control and crop performance in the cultivation of three container-grown ornamental shrubs: Old solutions meet new insights

Abstract

Weed control is necessary for successful and high-quality nursery production since weeds negatively affect produce yield and quality, especially when plants are grown in pot where the competition for nutrients and water is high. However, this agronomic practice represents an issue due to the high cost for weed removal and the environmental implications related to the use of herbicides. In the above cultivation systems, eco-friendly control of weeds is indeed difficult because the application of physical treatments, as for example those applied in open field, are often not possible. Alternative-to-chemical organic products have been proposed, including coconut disks, biodegradable plastics and various organic fibres derived from the woody industry and agricultural waste, although their durability in the pot and cost are considered constraints in their operational application. A hydro-compacting organic mulch composed of organic fibres and biodegradable glue, which makes the product adhesive and persistent on the substrate surface, is presented, together with other organic mulching products, in this work. Three different shrub species (camellia, cupressus and photinia), typically grown in containerized nursery production, were used to form a heterogeneous cultivation of different species in the same area to be representative of a real (commercial) nursery. The effects of the organic mulches were compared to untreated and chemical controls to assess their performances in terms of weed control, plant ecophysiological response, and crop yield and quality parameters. The organic mulches reduced the presence of weed by roughly 70% on average, sometimes performing at the same statistical level of the chemical control, while had no negative influence or even enhanced the other plant performance indicators (e.g., +11% dry weight in camellia, +72% net photosynthesis in water-stressed photinia, on average). The three species exhibited different capability in contrasting weed presence allowing the collection of useful information for the design of control strategies potentially exploitable at operational level.