The Importance of Diversity

The Importance of Diversity

Industrial systems are characterized by the homogenization of above and below ground diversity, otherwise known as “monocultures”.  The homogenization of agriculture is a global phenomenon.  According to Rural Advancement Foundation International, since 1900, approximately seventy-five percent of the world’s genetic diversity of agricultural crops have been eliminated, and replaced by the select varieties grown in monocultural operations—sugar cane, maize, rice, wheat, potatoes, soybeans, oil-palm fruit, sugar beet, and cassava—accounting for approximately seventy percent of global agricultural land-use. 

Monocultures pose a number of challenges to the environment and food and farming systems.  Compared to polycultures, monocultures are shown to be less productive and less resilient, and require tremendous amounts of time, energy, and resources to operate.   Lacking the compensatory functions of various ecosystem services, their homogeneity makes them more susceptible to disease, infestation, and ultimately collapse.  In contrast, Reiss and Drinkwater explain, “A high-functioning community is often a more productive one, where all available resources are utilized by the diverse set of individuals present…resulting in more complete resource utilization.” 

Investigators now are beginning to demonstrate a link between above and below ground diversity and greater crop performance and resilience.  Where at once when experts put forth the view that the human application of chemical fertilizers, produced healthy plants, recent research has demonstrated the opposite: Among others, it was Dr. Elaine Ingham who has most famously been accredited with demonstrating that the chemical and physical properties of the soil are determined by the quality of microbial life in the soil.  In her 1985 paper entitled “Interactions of bacteria, fungi, and their nematode grazers: effects on nutrient cycling and plant growth”, Ingham demonstrated the positive effects microbivours nematodes have on “microbial growth, nutrient cycling, plant growth, and nutrient uptake”, thereby inaugurating an explosion of interest in the roles these trophic levels play in well balanced soils.  A considerable concentration of these transactions have been focused within the rhizosphere, as elucidated by professor James F. White from Rutgers University through hiss research on the “rhizophagic cycle”, a term referring to “the mechanism for the transfer of nutrients from symbiotic microbes (bacteria and fungi) to host plants”.

Fungi have been estimated to appear 3.5 billion years ago.  Through long and nimble hairs, mycorrhizae (Greek for “fungus-root”) are able to access nutrient otherwise out of reach of plant roots, capable of even penetrating rock.  Through the production of certain acids, fungi are able to break down inorganic and mineral materials and can unlock and transport chemically-stored nutrient back to the host plant.   Additionally, fungi play a crucial role in bioremediation through the detoxification of contaminated soils and waters.  Scholars have even demonstrated the capability of pleurotus ostreatus and white-rot fungi to degrade other soil pollutants such as polycyclic aromatic hydrocarbons (PAH’s) as well as assist in the detoxification of crude oil.


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