A systematic approach to recycling organics for horticulture: comparing emerging and conventional technologies

Recycled organics: how best to use this resource? A three-year study took the first steps towards an answer by exploring emerging (biochar from pyrolysis) versus conventional (composting) processing technologies for their ability to convert recycled organics - city green waste and farm trash - into usable products that enhance horticultural productivity, with attendant carbon sequestration and environmental benefits. In this study, we compared organic products prepared from one common feedstock using four different technologies: windrow composting; a small mobile pyrolyser for on-farm processing; a medium pyrolyser for community or small business undertakings; and a large pyrolyser for high through-put requirements. The project then determined whether organic products enhance plant performance, are useable for horticulture and outperform or complement composting. This paper summarises some key outcomes from i) physical and chemical characterisation of organic products and ii) annual vegetable (tomato 'Rebel') and perennial fruit (blueberry 'Opi') field trials, thus providing the first step towards an understanding of the system from feedstock source to the farm.