Protecting Soil Biodiversity

The films Symphony of Soil and Dirt! aim to highlight the rare and intricate nature of the soil found on our planet.  As Dirt! points out, out of the endless expanse of space and matter materialized by the big bang, Earth is the only planet that we know of to possess the “living, breathing skin” of soil, which supports life and in turn is strengthened by the decaying matter upon it (Dirt! 0:30). Soil is the reason life is even possible on Earth, and is so filled to the brim with living organisms that it could be considered a living thing itself. However, this intricate living layer is often exploited and mistreated by human activities such as unsustainable agriculture practices and the depletion of natural capital to meet consumption demands. In order to preserve the soil which is so crucial to our existence and the well being of the planet, we must adopt more sustainable practices which work in harmony with natural processes. 

 A major concept emphasized by both films is the ancient and recycled nature of soil. Dirt! beautifully highlights that the elements in soil are “made from stars very different from our star, very far away, and has probably been recycled through dozens of stars before it got to us” (Dirt! 1:08). Soil is made of billions of years-old substances, and has culminated to a matter which is rare, complex, and life-giving. Through systems such as the carbon and phosphorus cycles, nutrients are recycled throughout these materials to perpetuate and nurture life. Then, as soil ages and more life grows, decays, and interacts upon it, the soil becomes richer, more complex. I think this fact is fascinating, as it conceptualized the ancient nature of the ground beneath my feet. As the textbook described in chapter 2, the carbon atoms in my skin could once have been part of an “oak leaf, a dinosaur’s skin, or a layer of limestone rock,” and the Nitrogen I am breathing could be the same atoms that someone inhaled hundreds or thousands of years ago (Miller, 55).

 Soil also is, itself, incredibly alive. Dirt! emphasizes that “with the amount of species that live in a teaspoon of dirt… it’s very obvious dirt may be more alive than we are” (Dirt! 1:47).  The pores which make up 50% of the soil under our feet are filled with air, water, and water vapor, and are where living things (like microorganisms) are able to flourish (Garcia 17:45). These countless organic beings drive the ability for soil to be productive and function efficiently, and therefore enable the ecosystem to thrive. So, essentially, these small beings and their relationships with the soil are responsible for the possibility of existence for entire ecosystems. These microorganisms are fed by the carbon absorbed by plants through photosynthesis, and the plant in turn receives the nutrient balance and equilibrium it needs to survive via those microorganisms. The plant exudates simple sugars, carbohydrates, and proteins so bacteria and fungi can grow and protect the roots of that plant. There are a “million organisms per teaspoon of soil” near a plant (Garcia 21:30). Fungi, which grow at the roots of plants, often produce a fruit body, which we refer to as a mushroom. Additionally, nitrogen (though it makes up the largest percentage of air in the atmosphere) is unavailable to us and to the chemistry/cycles of life except for by the important process of nitrogen fixation, which is undertaken by specific bacteria in the soil. If plants did not exudate “food” for bacteria and fungi to grow, nitrogen would not be available for us and other living beings to interact with. This is just one example of how intricate, complex, and intentional soil/plant processes are. 

Fig. 1, Functions of soil biodiversity.

Fig. 2, Soil Biodiversity

However, there are many unsustainable practices which deplete the nutrients of land and threaten the biodiversity and delicate balance of soil ecosystems. Dirt! asserts that “the demand for natural resources has completely changed our relationship with dirt” (Dirt! 25:35). Globally, we consider certain natural materials to be more fiscally valuable, and we destroy landscapes to acquire these resources. For example, mountaintop removal is a strategy people use to mine coal. Using this method, which Dirt! calls “strip mining with a vengeance,” companies “literally cut and level mountaintops” “in the name of cheap electricity” (Dirt! 25:55). Mountaintop removal and other mining practices occur on an enormous scale, and destroy all of the natural capital in their path. Insufficiently managed consumption such as this leads to the destruction of intricate ecosystems, and makes it very difficult for soil to recover to its former state. The biodiversity  accumulated over thousands or even millions of years is depleted so that humans can obtain things which they deem valuable.

Fig. 3, Mountaintop removal mining.

Agriculture is another realm in which the treatment of soil is concerned. In agriculture, nitrogen fertilizers can introduce an oversaturated amount of nitrogen and chemicals into an ecosystem and can deplete the soil. The overuse of fertilizers also leads to demands in high pesticide use and excessive use of water and fossil fuels (Garcia 37:16). Another unsustainable practice is plow-based agriculture on hillsides, and the repetitive growing and harvesting of the same crops on a single piece of land. Additionally, “70% of our freshwater resources on this planet now are used just for agriculture irrigation” (Garcia 53:39). Because of this, we are depleting our freshwater resources at an unsustainable rate. This is an issue because it could lead to water shortages for humans, for animals in the wild, and can disrupt freshwater and its dependent ecosystems around the globe. Aquifers in particular are being depleted, which is extremely problematic. The resulting salinization and erosion of soil also drastically affects the productivity or that soil to be used in  agriculture.

However, agriculture isn’t inherently destructive, and can be neutral or even beneficial to the soil “depending on how you treat it” (Garcia 40:10).  A solution to excess irrigation is no-drip lines, which when introduced to farmland, use “vastly less water and less electricity to bring water to your field crops” (Garcia 55:19). Farmers can also use varying crops to cover more soil surface area in order to decrease evaporation from the soil. The soil therefore retains more water and there is less need for continuous and excessive irrigation. This demonstrates that innovation can be used to alleviate issues like irrigation. Additionally, regarding the depletion of soil nutrients  Dr. Fred Kirschenmann asserts in Symphony of Soil that, “The most important thing we can do right now is to take seriously… the Law of Return. What he meant by that was: the best way to retain the living capacity of the soil and its capacity for self-renewal is to return to the soil all of those things that we use to get from the soil” (Garcia 47:22). This can be seen done in a sustainable manner in the film’s depiction of a farm in Punjab which reintroduces carbon and nitrogen by composting straw, green matter, dung, and raw phosphate on recently harvested or depleted land. Compost can be used to help “grow” topsoil that is suitable for growing crops, and can help solve plant disease problems. This shows that innovative thinking about sustainable agriculture can help solve environmental issues regarding the food industry, as well as produce better, healthier crops. 

Symphony of Soil describes agriculture as a “dance with nature” (31:20). On a farm, farmers must act in harmony with the land, while also acting decisively with the goal of creating a surplus of product. The film described that we should attempt to mimic natural systems in agriculture in order to produce crop yields that are in harmony with nature, don’t harm the soil, and can get us the food we need. Treatment of soil that mimics the natural occurrences of crops in nature without pesticides or inorganic fertilizers are significantly better for the environment in which farmers decide to plant the crops for harvest. Additionally, yields are more successful when crops are planted in a way that mimics their natural environment. 

In conclusion, soil is an intricate and crucial aspect on Earth which practically grants us our lives, so we must adopt more sustainable practices if we want a healthy and biodiverse world  in the years to come. We must learn to respect and appreciate our soils as a life-giving foundation and treat it as such. As Symphony of Soil asserts, “Only rarely have we stood back and celebrated our soils as something beautiful, and perhaps even mysterious” (Garcia 0:05). It is time we acknowledge the beauty, delicacy, and power of a healthy soil ecosystem, and take the time to learn how to nurture it. 

Word Count: 1432

Question: What are some ways people who are not connected to the agriculture industry in any way encourage sustainable agriculture practices?


Burns, Paulette. “International Year of Soils 2015.” UK Centre for Ecology & Hydrology, November 17, 2017. 

Dirt!. Directed by Gene Rosow and Bill Benenson. 2009. Common Ground Media. 

Garcia, Deborah K. “Symphony of Soil.” YouTube. YouTube, November 23, 2018. 

Miller, G. Tyler, and Scott Spoolman. Living in the Environment. Stamford, CT: Cengage

Learning, 2018.

“What Is Mountaintop Removal Mining?” Earthjustice, September 17, 2015. 

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