Healthy soil, healthful food
by Maura Rendes
This article was originally published in March 2015
A nation that destroys its soil destroys itself.
— Franklin D. Roosevelt
Roosevelt’s words might bring to mind images of pavement or resource extraction, yet our most common agriculture practices also are destroying our soil.
Modern industrial agricultural practices have been impacting our once-rich below-ground ecosystem since the early 20th century and we’re just beginning to understand how it’s affecting our health.
When compared with the nutrient value of the foods our grandparents ate, what we consume today has substantially lower nutritional value. According to the Journal of the American College of Nutrition, today’s foods typically are lower in protein, calcium, phosphorus, iron, riboflavin (vitamin B-2) and vitamin C. It’s now possible to buy an orange that contains zero vitamin C.
Why is this happening? One potential cause is changes in plant varieties. If breeders are focused on other factors besides nutritional value (yield, disease resistance, etc.), then the new varieties may decline in nutrient concentrations. Depleted soil may be another reason.
“Historic farm management practices have degraded soil organic matter, reducing the inherent fertility of the soil,” says Chad Kruger, Director of the Washington State University Center for Sustaining Agriculture and Natural Resources. “The conventional thinking was that we could replace that lost fertility by using artificial fertilizer. However, there’s now a growing realization that managing for soil and food quality requires more than just replacing the big three nutrients — nitrogen, potassium and phosphorus (NPK) — with synthetic fertilizers.”
Kruger says the most commonly attributed cause for reduced nutrition in foods is the “dilution effect” from increasing yields. The logic goes: modern industrial agriculture has increased yields through improved genetics, mechanization and use of NPK fertilizers. At the same time, management for nutrients in soils hasn’t kept up, so we’re producing more output (food) per acre without increasing the amount of nutrients.
For instance, adding nitrogen fertilizer may double the yield of oranges, but if there’s no focus on the micronutrients associated with vitamin C, increasing yield of oranges depletes the micronutrients — and vitamin C levels are reduced in an orange. Kruger says scientists are working to understand whether improving soil management in both conventional and organic systems can help mitigate this dilution effect.
New research affirms that “a healthy and diverse soil microbiome can foster a more diverse and protective human microbiome,” says author and physician Dr. Daphne Miller.
According to the Journal of Allergy and Clinical Immunology, our decreased access to a diverse soil microbiome may be linked to the rise in asthma and allergies in Western societies.
Even our mental health reportedly is linked to healthy soil. (See the Discover Magazine article, “Is dirt the new Prozac?“)
Humans are responsible for the degradation of 40 percent of the world’s agricultural land, according to a report from the United Nations Environment Programme. That’s why sustainable farming practices, together with conscientious consumers, can help advance restorative agricultural practices that produce the healthiest food possible.
PCC Farmland Trust works with producers to ensure sustainable practices and improvement of natural resources – air, water, soil and habitat. There are many others working for these goals, around the globe and in our backyard.
Washington State University’s Puyallup Research and Extension Center, for instance, is a pioneer in soil science, developing tools and resources to help farmers manage soil effectively. “The results of our research provide farmers with guidance on using organic amendments and cover crops as sources of organic matter and nutrients for profitable crop production while improving soils,” says WSU’s Craig Cogger. “Our latest research is focused on reducing tillage in organic farming systems, which can lead to further long-term benefits to the soil.”
The Farmland Trust’s latest conservation project, Helsing Junction Farm in Rochester, Washington, has had great success in re-mineralizing soil with the help of the Natural Resources Conservation Service (NRCS). By applying micronutrients such as sea minerals, farmers Annie Salafsky and Susan Ujcic have seen “increased yield, improved soil tilth and microflora, better drought tolerance, improved disease and insect resistance, better keeping qualities, and increased nutrient density, which we experience as better flavor.”
With resources such as WSU and NRCS, farmers in Puget Sound are well-situated to incorporate soil-based farm practices, or transition toward these practices over time.
Maura Rendes is the marketing and community engagement manager for PCC Farmland Trust.