Though not recognized as such at the time, the crisis began with the first agricultural Green Revolution in the late 1950’s and throughout the 1960’s. Because planners were concerned about human population outpacing food production, plant breeders started developing new, high-yielding varieties of cereal grains, particularly wheat and rice. The newly developed crops were high-yielding because they managed to pull more nutrients (e.g., nitrogen, phosphorus, and potassium) out of the soil as compared to older varieties.
In addition to new crop varieties, science developed pesticides and farmers applied them to their fields in earnest, especially in the late 1950’s and early 1960’s. Tons of DDT were dumped onto fields, thus controlling plant-eating insects. Food production began to rise.
Apparently, few people were concerned about any potential impact of poisons on soil microbes, worms, fungi, and other life forms necessary for soil health.
At the same time, the petrochemical industry developed artificial (synthetic) fertilizers. By about the early 1970’s, worldwide food production began to increase at an unprecedented rate. Such was the start of the second Green Revolution. Due to massive application of both synthetic fertilizers and irrigation water, it lasted to about 1985 or so. Annual grain production increased by 160%.
When the Green Revolution began, the start of a long period of soil degradation also began. For quite awhile, it was unrecognized. The widespread use of DDT on crops (and thus, on soil as well) began not long after WWII, well before the Green Revolution. It was banned in the USA in 1972. The primary reason for the ban was the harm it caused populations of raptors, or birds of prey. The harm to soil generally was unknown at the time. In agriculture, other poisons took the place of dichlorodiphenyltrichloroethane (DDT). Herbicides also contributed to the ongoing degradation of soil. So, too, did the massive use of synthetic fertilizers. To understand WHY and HOW petrochemicals (in this case, synthetic fertilizers and synthetic pesticides) cause the degradation of a most valuable resource, let’s look at soil in a bit more detail.
Like all others, soil is a highly complex natural ecosystem. Most ecologists would agree that a healthy, natural ecosystem is more complex than anything ever built by humans. Anything. So, the first thing to keep in mind is: soil is a living system with more complexity than any machine or system made by us. That complex, living system is the basis of our food supply. Almost all our plant and animal food products ultimately come from the soil. Instead of essentially poisoning it with artificial petrochemicals, we should be revering it and treating it with the utmost care. [See Pal, R. 2006 in References.]
Fifty or more years ago, a good topsoil consisted of 25% air, 25% water, 45% minerals, and 5% humus. The last item, humus, is partially decayed organic matter. It’s derived primarily from dead plants, plant parts (such as fallen leaves, twigs broken off, tree bark, etc.), dead animals and microbes, and animal wastes. Humus is crucial to soil fertility. It provides not only macronutrients such as Nitrogen (N), Phosphorus (P), & Potassium (K), and the secondary nutrients Calcium (Ca), Magnesium (Mg), and Sulfur (S), but also the micronutrients Zinc (Zn), Manganese (Mn), Iron (Fe), Chloride (a form of Chlorine, Cl), Copper (Cu), Molybdenum (Mo), and Boron (B). When industrial farmers use the main synthetic fertilizer made from petroleum, all the soil gets is macronutients. Over time, the soil slowly is degraded. Today’s soil contains humus hovering around 1%, and that’s only a part of what makes up the Soil Crisis.
Other Aspects of Soil Important to Humans
About 25% of the world’s land biodiversity is found in soil. One result of that: biodiverse soil bacteria provide us with new antibiotics. Also, biodiversity overall makes a soil ecosystem healthier and more resistant to environmental stresses such as disease in soil plants and animals, drought, and other damage to soil food webs.
Soil filters water. For the most part, large groundwater aquifers are located inside “solid” rock. Rock has many tiny crevices, cracks, and microscopic pores which allow water molecules to enter. They accumulate there over thousands and thousands of years. Before ever getting to underlying bedrock, soil filters the water as it travels downward. That’s why water from a drilled well generally is “pure”.
Soil is an important carbon sink. It sequesters carbon dioxide, thus keeping excess CO2 out of our atmosphere.
The mineral portion of soil is composed of various combinations of sand, silt, and clay. Individual clay particles are so tiny they can be seen only with a high-powered microscope. As such, they exist in what’s known as a colloid, or in colloidal form. In that state, they have a net negative electrical charge. This means they attract positively charged mineral nutrients such as calcium, magnesium, iron, potassium, etc. The nutrients thus are prevented from leaching down into the lower depths of the subsoil, out of reach of many plant roots.
Humus also exists in colloidal form. It, too, holds nutrients in the topsoil where they can be absorbed by plant roots. The colloids making up both inorganic clay and organic humus are the most chemically active parts of any soil. They are crucial to soil fertility. Humus is a great source of nutrition for plants, and by releasing the nutrients slowly during decomposition, the plant roots are not “burned” when the nutrients are absorbed. The petrochemical fertilizer, ammonium nitrate, sometimes does damage to plant roots by quickly overwhelming and “burning” them.
Green land plants get most of their water and nutrients (other than glucose, which they make themselves) from soil. Such plants not only are the basis of our food web, but also a significant source of the oxygen we require to live.
Petrochemicals, a major cause of soil degradation, damage or destroy soil biodiversity by killing many different types of microbes which are necessary to soil health. [See Pal, R. 2006 and Goudie, Andrew S. 2019 in References.] Bacteria, the most numerous of the soil microbes, work to decompose plant and animal matter. Thus they promote nutrient cycling. So do fungi and actinomycetes. Some bacteria can pull nitrogen out of the air and “fix” it into certain plants known as legumes (e.g., alfalfa, clover, and beans). Actinomycetes resemble both bacteria and fungi, and they aid in decomposition of organic matter, thus also contributing to the cycling of nutrients in the soil ecosystem. In addition to decomposition, fungi help bind soil particles into aggregates, and so aid in resistance to wind and water erosion.
Mycorrhizal fungi in soil are especially important to green plants. “Mycorrhizal” refers to a plant’s root system. These fungi live on the roots of plants in a mostly symbiotic (mutually beneficial) manner. Their hyphae – fungal feeding tubes – allow the host plant’s roots to take in more water and nutrients than they otherwise could. The practices of industrial farming – with their use of synthetic fertilizers and herbicides – are destroying these valuable fungi. Thus, over time, crop yields ultimately will be reduced because of soil degradation.
Factory farming also exacerbates wind and water erosion of soil, thus contributing even more to soil degradation.
