CRUCIAL: Closing the rural-urban nutrient cycle - Long-term field site with urban fertilizers and organic amendments

It is generally recognised that the urban areas are practically dissociated from the rural areas when looking at recycling of nutrients and organic matter from the food and waste stream of modern society. Investigations of the effects of various urban waste products on soil nutrient turnover, fertiliser value, crop quality and environmental impacts are therefore needed, both for agronomic and human + ecosystem health reasons.

This project forms part of a coherent effort to re-invent urban management with the view to close the rural urban nutrient cycle. It will ensure the establishment of a field-scale facility for assessing the feasibility of improved recycling of nutrients from urban areas to both conventional and organic farms, in the form of a long-term field trial. It serves as a field monitoring programme on soil quality changes wrought about by using urban fertilisers in the long-term and as such attempts to take eventual unforeseen ill effects of increased re-circulation into account.

The field trial comprises the following permanent treatments:

Urban Fertiliser treatments:

  • Human Urine (from urine separating toilets)
  • Composted organic household waste (normal or 3 x accelerated application rates)
  • Degassed Sewage Sludge (normal or 3 x accelerated application rates)

Reference treatments:

  • Cattle Slurry
  • Deep Litter (normal or 3 x accelerated application rates) 
  • Mineral NPK fertilizer at recommended rates 
  • No application of fertiliser (soil nutrient mining / extractive strategy).

Period: The trial was initiated in 2001, but the current design implemented in 2003.

Project head: Jakob Magid

Other partners: CREAM, DAAS and BGORJ.

Funding: FØJO (initially), other partners in later years.

Danish website: https://plen.ku.dk/om/pfv/forsoegsgaarde/omfsg/arealer/vaerksted/crucial/