Research findings: allotments have good food yields without sacrificing soil quality

Fruit growing on Hall Green allotment
Fruit growing on Hall Green allotment

There are around 330,000 allotment plots in the UK, covering more than 8000 hectares and demand is growing, with more than 90,000 people currently on allotment waiting lists in the UK. 

Findings of a study published in the Journal of Applied Ecology

  • Soils under Britain’s allotments are significantly healthier than intensively farmed soils.
  • By growing on a small-scale in urban areas, it is possible to produce food sustainably without damaging the soil.

Science Daily reports that ecologist Dr Jill Edmondson from the University of Sheffield took soil samples from 27 plots on 15 allotment sites, local parks, gardens across the city of Leicester and surrounding agricultural land. She measured a range of soil properties, including soil organic carbon levels, total nitrogen, and the ratio between carbon and nitrogen (all directly related to the amount and quality of organic matter in the soil) as well as soil bulk density, an indicator of soil compaction.

Intensive farming often results in significant declines in soil organic carbon stocks, as well as reducing the ability of soils to store water and nutrients, and damaging soil structure, on which food production — and other services such as carbon storage, flood mitigation and locking up pollutants — depends.

Compared with local arable fields, the allotment soil was significantly healthier: allotment soil had 32% more organic carbon, 36% higher carbon to nitrogen ratios, 25% higher nitrogen, and was significantly less compacted. Dr Edmondson says:

University of Reading study
University of Reading study

“We found remarkable differences in soil quality between allotments and arable fields. Our study shows how effectively own-growers manage soils, and it demonstrates how much modern agricultural practices damage soils.

“Allotment holders are able to produce good food yields without sacrificing soil quality because they use sustainable management techniques. 95% of allotment holders compost their allotment waste, so they recycle nutrients and carbon back to their soil more effectively.

“An estimated 800 million city dwellers across the world participate in urban food production, which makes a vital contribution to food security. Our results suggest that in order to protect our soils, planning and policy making should promote urban own-growing rather than further intensification of conventional agriculture as a more sustainable way of meeting increasing food demand.

Vegetables growing on Hall Green allotment
Vegetables growing on Hall Green allotment

“Using urban land, including domestic gardens, allotments and community gardens for own-growing is an important and often overlooked way of increasing productivity whilst also reconnecting urban dwellers with food production.

“As well as improving food security, studies show that own-growing has direct physical and mental health benefits, and can provide access to sustainably produced fruit and vegetable crops without the associated food miles.”

As a result of the findings, the authors say that planners and policy makers should increase the number of allotments available.


Jill L. Edmondson, Zoe G. Davies, Kevin J. Gaston, Jonathan R. Leake. Urban cultivation in allotments maintains soil qualities adversely affected by conventional agriculture. Journal of Applied Ecology, 2014; DOI: 10.1111/1365-2664.12254 – gives link to pdf.

 

The University of Reading studies of soil erosion on farmland: see picture above left and http://www.ecifm.rdg.ac.uk/erosion.htm