A rainbow of soils feeds the world

Soil has taken billions of years to form, but with misuse can be destroyed in just a decade or two. As we celebrate World Soil Day, Adama takes a closer look at this precious resource

Along with water and the sun, soil is the third key ingredient for growing a crop. The UN FAO’s says healthy soil has the the capacity to function as a living system, that sustains plant and animal productivity, maintains or enhances water and air quality, and promotes plant and animal health. Caring for the soil and using targeted applications of fertilizer and crop protection products allow farmers to produce the food the world needs, while protecting the environment and preserving resources for future generations. Soils also have a role in locking away carbon that could form into damaging greenhouse gases. Some studies¹ & ² suggest that there are 1,500 billion tonnes of carbon locked in soil to a depth of one metre, which is more than the combined total in vegetation and the atmosphere.

Global soils have been classified by the US Department of Agriculture into a rainbow of types each with its own colour. There are 12 types in all. Only around 30% of the world’s land area is made up of soils that can successfully support crop production. Strikingly, the world’s most fertile soils are not in the regions of the world where the greatest amount of population growth is expected to take place over the next 30 years. That will mean that in regions of peak population growth, soils that can produce food will need to be nurtured and protected, while soils in other regions will increasingly have to feed global consumers as well as local ones.

Soil improvement case studies

The Hummingbird Project works across six Indian states and since 2011 has helped more than 2,500 farmers improve their soil management including funding irrigation, water harvesting and compost systems. It is called the Hummingbird project after a traditional story that sees a hummingbird going back and forth to a river to collect water that eventually puts out a fire. For more see: Link.

In Northern Ghana, Deco Deco is social business project that has established a farmer-owned cooperative that produces organic fertilizer that has helped some growers double crop yields, improving local food security and incomes. See link.

LEAF (Linking Environment And Farming) is a UK-based charity encouraging farmers to produce more sustainably by using Integrated Farm Management techniques. Operating in more than 35 countries, soil management is a key focus for the organisation and it has published a 36-page guide, which can be found here: Link.

¹Batjes, Niels H. (June 1996). "Total carbon and nitrogen in the soils of the world". European Journal of Soil Science. 47 (2): 151–163. doi:10.1111/j.1365-2389.1996.tb01386.x. and Smith, Pete (2007). 

²"Soil Organic Carbon Dynamics and Land-Use Change". In Braimoh, Ademola K.; Vlek, Paul L. G. Land Use and Soil Resources. Stockholm, Sweden: Springer. ISBN 978-1-4020-6777-8. LCCN 2007941782.

For more on soil classification see the USDA’s National Conservation Service: https://www.nrcs.usda.gov/wps/portal/nrcs/main/soils/survey/class/

The UN FAO soil portal is here: http://www.fao.org/soils-portal/en/

Source: USDA
Source: USDA
Source: USDA