Cities are utterly dependent on nature’s services, including provisioning of food and fibres from healthy soil. Healthy soil is one of six essential bio-geophysical conditions in the IES. “Soils within the city and soils associated with the city’s economy, function and operations should meet their ranges of healthy eco- system functions as appropriate to their types and environments” (www.ecocitystandards.org). This means that ecocities and their residents work to ensure that fertility of soil is maintained or improved both within cities and in the rural areas all around the world from which cities draw sustenance.
Lester Brown, founder of the Worldwatch Institute and the Earth Policy Institute, identifies soil erosion as one of the major contributors to the collapse of urban civilizations. Modern technologies, including the use of petroleum- based fertilizers, have artificially raised the productive capacity of agricultural land. However, this practice is not sustainable. Approximately one-third of global agricultural land is losing top soil faster than it is being replaced (Brown 2009). Drought and agricultural practices that include intensive tillage result in soil erosion and are anticipated to worsen due to climate change (Brown 2009). It takes approximately 500 years for one inch of top soil to regenerate in the temperate, wheat growing areas of North America (National Geographic 2010). In the future, a different approach to regenerating healthy soil is needed.
An important question for those interested in ecocities is: what can be done to support healthy soils in rural areas? Cities occupy two percent of the earth’s surface, but account for 75% of global resource demand (Giradet 2004). Therefore, while a focus on urban agriculture is important, a focus on the sustainability of rural agriculture is essential. Permaculture (Mollison 1997), the practice of permanent culture, includes an emphasis on building soil fertility and is a promising start. Permaculture initiatives are springing up within cities and small rural land-holdings. But how can urban residents engage in advancing sustainable agriculture at large scales? Purchasing fair-trade and organically produced food creates a market signal that stewardship of the land is of value. But is there more that the residents of an ecocity could do?
Answers include engaging in local community planning initiatives and working with local government officials in efforts to shift development toward existing centres of social and economic vitality while strategically removing deteriorating buildings and opening landscapes for gardening and composting to build healthy soils. Tools include “willing seller” deals and transfer of development rights (Pruetz, 1997)
Brown, Lester. 2009. Plan B 4.0. Mobilizing to Save Civilization. New York: W.W.
Giradet, Hebert. 2004. Cities, People, Planet: Livable Cities for a Sustainable World.
Mollison, Bill. 1997. Permaculture: A Designers’ Manual. (original 1988) Tyalgum NSW:
National Geographic. 2010. Collapse: Based on the Book by Jared Diamond (documentary film). Universal City, CA: Vivendi Entertainment.
Pruetz, Rick. 1997. Saved by Development. Burbank Ca: ARJE.
A variety of factors are important:
1. need to consider total quantity, quality and distribution across city
2. need to consider availability of (buildings, parks, agriculture)
3. definition of soil health depends on soil type/location
May be useful to divide indices based on classifications of soil use: agriculture soils per capita, recreational use, building soil.