Dissolved air flotation (DAF) separates phosphorus (P)-rich fine solids from anaerobically digested dairy manure, creating opportunities to export surplus P to the marketplace as a bagged plant food product. Seedlings of tomato and marigold were amended at various volume per volume (v/v) ratios with plant foods consisting of fine solids upcycled (i.e., transformed into a higher quality product) by drying and blending with other organic residuals. A plate competition assay was conducted to assess the fine solids’ potential to suppress the plant pathogen Rhizoctonia solani. Plant foods were comprised of 2.0–2.1% N, 0.8–0.9% P and 0.6–0.8% K. Extractions indicated that plant foods contained a mixture of plant-available and slow-release P. At 6% v/v plant food, dry biomass of marigold and tomato were six-times greater than the unamended control and not significantly different from a market alternative treatment. Fine solids exhibited negligible potential to suppress R. solani. This study indicates that DAF-separated fine solids could be used to support horticulture, providing information for design of a circular economy approach to dairy manure nutrient management. Life cycle assessment and business model development for this nutrient recovery strategy are necessary next steps to further guide sustainability efforts.

Automatic self-attaching collars, immobilising drugs, pen traps, and salt-lick lures were assessed as aids to marking feral goats in mountain country. Salt licks were ignored. Pen traps were prone to damage or could deter goats from using the area. Automatic collars required about 0.6 man-days work per collar taken, but wind-throw and disturbance by deer and trampers reduced their effectiveness. Darts shot from a Paxarm gun were used to inject non-lethal immobilising drugs. Fentanylazaperone was preferred to Rompun because recovery from it was accelerated with the antidote Lethidrone. Drug absorption was not materially hastened with hyaluronidase enzyme. Goats caught at a rate of 1/1.3 man-days were aged, sexed, and marked with a steel eartag, a chainlink collar, and an epoxy resin colour-coded horn cone. Coded cones were readable up to 150-200 m with x 9 binoculars.

The authors would like to make the following correction for the published paper [...]

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