By guest contributor Christine McCullum-Gomez, PhD, RD, LD
Healthy food can only be produced if our soils are healthy. This is because soil health and fertility have a direct influence on the nutrient content of food crops (FAO, 2015).1 Despite its importance, an estimated 33% of the planet’s soil is degraded by physical, chemical, or biological causes.2,3 To highlight this problem, the United Nations (UN) declared 2015 as the International Year of Soils.4
The UN Food and Agriculture Organization (FAO) identified 6 key messages about healthy soils for a healthy life. These include:
- healthy soils are the basis for healthy food production
- soils are the foundation for vegetation, which is cultivated or managed for feed, fiber, fuel, and medicinal products
- soil supports our planet’s biodiversity and they host a quarter of the total
- soils help to adapt to climate change by playing a key role in the carbon cycle
- soils store and filter water, improving our resilience* to floods and droughts
- soil is a non-renewable resource; its preservation is essential for food security and our sustainable future.5
If soils are important to humanity, why aren’t we doing a better job of protecting this nonrenewable resource?
Healthy Soils Are the Basis for Healthy Food Production
Soil is one of nature’s most complex ecosystems;6 a single gram of healthy soil contains millions of organisms.2 Collectively referred to as soil biodiversity, algae, bacteria, fungi, insects, and other soil organisms are interdependent in a complex food web, which is essential for food security and nutrition.7 With a global population that is projected to exceed 9 billion by 2050, compounded by competition for land and water resources and the impact of climate change, our current and future food security depends on our ability to increase yields and food quality using a shrinking land base available for agriculture.1 Furthermore, it is estimated that 28% of the world’s agricultural land grows crops that are wasted, which contributes to wasting water and increasing our carbon footprint.2
In some countries, intensive crop production has depleted the soil, jeopardizing our future ability to continue growing food in these areas. Agricultural soils in intensive farming systems where a limited variety of crops are grown may be less resilient8 and more vulnerable to such changes than soils in natural ecosystems** where the diversity of the soil micro-organism community may allow more rapid adaptation.8,9 Our planet’s severe loss of soil biodiversity has been driven by homogenization of agricultural systems, the spread of monoculture crop production, inappropriate use of agrochemicals, and excessive soil disturbance caused by continuous tillage.8
In contrast to destructive farming practices, diverse farming approaches that promote the sustainable management of soils include agroecology, organic farming, conservation agriculture, agroforestry, and zero tillage. Sustainable soil management practices could lead to average crop yield increases of 58% without the use of synthetic chemical inputs or genetically engineered food crops (referred to in the marketplace as GMOs).1,2 For more information on sustainable soil management practices, see the UN FAO’s infographic, Healthy Soils Are the Basis for Healthy Food Production.1
A comprehensive study of organic and conventional strawberry ecosystems** suggested that organic production methods resulted in both higher quality soil and higher quality strawberries. The organically farmed soils were higher in carbon and nitrogen and had greater microbial biomass and activity as well as greater functional gene abundance and biodiversity. Greater functional gene diversity in organically managed soils suggests that organic systems may support more stable or resilient ecosystem functioning.10 The study authors suggest that the large differences in soil microbial biodiversity between the conventional and organic systems are likely due to:
- Fumigation of the conventional fields with methyl bromide, which severely limits or eliminates soil life (good and bad) in the conventional system.
- Not spraying synthetic pesticides on the organic fields allows microbes to thrive.
- Applying double the amount of compost to the organic fields discourages disease-causing microbes while promoting diversity of beneficial microbes.10
Organic agriculture supports biodiversity. It is fundamentally different from conventional agriculture because its guiding land management paradigm is based on a systems view. The systems view recognizes the importance of functional relationships and interconnections between biodiversity (plants, soil organisms, insects, fungi, and animals) in an agroecosystem*** and the environment.7
In organic systems, land management practices that promote soil biodiversity and soil quality are emphasized and the goal is to maintain a sustainable agricultural system.7 Within an organic soil stewardship paradigm, “Soil and soil management is the foundation of organic production. Organic growing systems are soil-based, they care for the soil and surrounding ecosystems and provide support for a diversity of species while encouraging nutrient cycling and mitigating soils and nutrient losses.”11
The Healthy Soil Solution – Key to Climate Mitigation and Adaptation
According to UN FAO, “given the enormous amount of carbon stored in the world’s soils, microorganisms are extremely significant to efforts to mitigate climate change.”
Because micro-organisms are capable of breaking down a wide range of organic substances, they have great potential for use in removing contaminants and returning soil to a state in which it can be used safely for agriculture. Farming practices that increase soil microorganism biodiversity include crop rotation, “green fertilizer” (cover crops) and organic manure fertilizer, no-till agriculture, water-conserving irrigation practices, and “biological control agents,” or the natural enemies of pests.8 These strategies have great potential in adapting agriculture to the effects of climate change. Microorganisms such as mycorrhizal fungi and rhizobia that contribute to plant nutrition increase plant productivity without the greenhouse gas emissions associated with the production, transport and application of synthetic fertilizers.8
As part of the Center for Food Safety’s involvement in The United Nations Framework on Climate Change (UNFCC) events in Paris, France (from November 30 through December 11, 2015), the organization will launch a new program called Soil Solutions to provide additional information on soil carbon and actions people can take to help rebuild soil health and stabilize the climate. Here, their presentations to policy makers will center on Healthy Soil – Key to Climate Mitigation and Adaption Strategies.12 You can also read the Center for Food Safety’s 2015 report titled Soil & Carbon: Soil Solutions to Climate Problems.13
Do your part to support healthy soils—continue reading for helpful resources to get you started.
About the author: Dr. McCullum-Gomez, PhD, RD, LD is a consultant, speaker and writer with areas of expertise in community food security, public health nutrition and sustainable food systems. You can learn more about her work at www.sustainablerdn.com.
*Resilience is defined as the ability of an ecosystem** to recover from or resist disturbances and perturbation, so that the key components and processes of the system remain the same.7
**An ecosystem is a dynamic complex of plant, animal, and microorganism communities and the non-living physical environment interacting as a functional unit. Ecosystems include physical and chemical components such as soils, waters, and nutrients that support the organisms living within them and interactions among all organisms in a given habitat. The health and well-being of human populations depend upon the services provided by ecosystems and their components—including organisms, soil, water, and nutrients.7 Agriculture lands and coasts managed sustainably as ecosystems contribute to wider functions such as maintenance of water quality, water infiltration, erosion control, carbon sequestration, and pollination.6
***An agro-ecosystem is an ecosystem designed and managed by humans to produce agricultural goods.7
Food and Agriculture Organization of the United Nations (FAO). Healthy soils are the basis for healthy food production (Infographic). Rome, Italy: FAO, March 26th Available at: http://www.fao.org/resources/infographics/infographics-details/en/c/281883/
United Nations Food and Agriculture Organization (UN FAO). 2015 – International Year of Soils. Healthy soils for a healthy life. How much do you know about soils? Available at: http://www.fao.org/soils-2015/news/news-detail/en/c/317128/
Jarroud M. The soil, silent ally against hunger in Latin America. Tierramerica – Environment and Development. Santiago, Chile. December 14th Available at: http://www.ipsnews.net/2014/12/the-soil-silent-ally-against-hunger-in-latin-america/
United Nations Food and Agriculture Organization (UN FAO). 2015 – International Year of Soils. Healthy soils for a healthy life. Available at: http://www.fao.org/soils-2015/en/
United Nations Food and Agriculture Organization (UN FAO). Healthy soils for a healthy life. Key messages. Available at: http://www.fao.org/soils-2015/about/key-messages/en/
Food and Agriculture Organization of the United Nations (FAO). Agricultural Biodiversity in FAO. Rome, Italy: FAO; 2008. Available at: ftp://ftp.fao.org/docrep/fao/010/i0112e/i0112e.pdf
Underwood T, McCullum-Gomez, C, Harmon, A, et al. Organic agriculture supports biodiversity and sustainable food production. Journal of Hunger & Environmental Nutrition;2011:6(4):398-423. DOI: http://dx.doi.org/10.1080/19320248.2011.627301
Food and Agriculture Organization of the United Nations (FAO). Coping with Climate Change – The Role of Genetic Resources for Food and Agriculture. Rome, Italy: FAO; 2015. Available at: http://www.fao.org/3/a-i3866e.pdf
Mocali, S., Paffetti, D., Emiliani, G., Benedetti, A. & Fani, R. Diversity of heterotrophic aerobic cultivable microbial communities of soils treated with fumigants and dynamics of metabolic, microbial and mineralization quotients. Biology and Fertility of Soils;2008:44:557–569.
Reganold JP, Andrews PK, Reeve, JR, et al. Fruit and soil quality of organic and conventional strawberry agroecosystems. PLoS ONE;2010:5(9): doi:10.1371/journal.pone.0012346
Wander M. Organic soil stewardship. In: USDA – Science & Technology Training Library, Webinar Portal for Conservation of Natural Resources. Environmental Benefits of Organic Agriculture: Soil. August 27th 2015 (webinar). Available at: http://www.conservationwebinars.net/webinars/environmental-benefits-of-organic-agriculture-soil
Donlon D. Center for Food Safety heads to Paris for UN’s Historic Climate Summit. Food for Thought. The Center for Food Safety (blog). October 30th Available at: http://www.centerforfoodsafety.org/blog/4109/center-for-food-safety-heads-to-paris-for-uns-historic-climate-summit
Donlon D, Riggs P. Soil & Carbon: Soil Solutions to Climate Problems. Washington DC: Center for Food Safety;2015. Available at: http://www.centerforfoodsafety.org/files/soil-carbon-pamphlet_finalv2_88688.pdf
Nichols K. The Year of Soil. Rodale’s Organic Life. May/June 2015, p. 44. Available at: https://www.nextissue.com/magazines-issues-summaries/rodales-organic-life-magazine-may-june-2015-edition/