California Farms Are a Silent but Sizable Source of Air Pollution

I want to start off this blog post by giving an overview of my agricultural/gardening background since it has contributed to the holistic view I have and how I interpreted the article and the original research. I also will link to other articles and documentaries (most in Scientific American) I have read over the past 14 years that have formed my current perspective of this many-faceted topic. 

I grew up in a community that still had enough peripheral land being farmed that many of my classmates from junior high on up were children of farmers. Gardening has been a part of my life since before I can remember, which was probably when I was a toddler and would pick raspberries or peas out of my family’s garden. As I grew older, I was involved in other areas of the family garden (which I despised at the time), but I became a backyard gardener, by choice, 13 years ago after my husband and I were married and had a garden area in our first rental and I realized how therapeutic it was for me to be out in the soil during the growing season. Over the years, my personal knowledge of gardening techniques has expanded as I have studied and applied various organic gardening and sustainable ways to grow food. 

About 7 years ago, I was introduced to a gardening method designed by Jacob Mittleider from his experiments in his nursery near Loma Linda University to determine what made a plant healthy or not healthy and that is, a plant needs sixteen essential minerals and nutrients. Three are found in the atmosphere and water (carbon, oxygen, and hydrogen), but the other thirteen need to come from the soil: nitrogen, phosphorous, potassium, calcium, chlorine, magnesium, manganese, sulfur, copper, zinc, iron, boron and molybedenum.

Modern agricultural practices routinely apply only 3 of these 13 essential soil-nutrients in the form of the fertilizer NPK (nitrogen, phosphorous, and potassium). The problem with this is that for the plant to be able to pull up the nutrients it needs from the soil, it needs all 13 soil-based nutrients to be in the correct ratios, which gets out of balance when only NPK or one or two other soil amendments are applied to the soil.

However, when a plant has all 13 of the soil-based nutrients it needs, then not only is the plant healthier and more resistant to pests and disease, but the food it grows has a higher nutritional content - and there is a direct correlation between the decline of food nutrient and mineral density and the increased use of modern agricultural practices.

So when I saw the review article in Scientific American, California Farms Are a Silent, but Sizable Source of Air Pollution, I was intrigued. Deidre Lockwood reviews the study that had been published a week earlier in the journal, Science Advances, on 31 January 2018, Agriculture is a major source of NOx pollution in California in which researchers determined that agricultural LAND, not gasoline or diesel fueled vehicles used in agriculture, were a major contributor to the ozone gas, nitrogen oxide (NOx) in California's atmosphere. I will be honest, this article certainly confirmed my existing bias that the method in which our produce is begin grown in the US and other nations is not sustainable for our bodies OR the environment, especially when it creates a paradox that agricultural land is actually contributing to ozone gases rather than decreasing it by the plants taking in carbon dioxide through photosynthesis. 

NOx emissions from on-road vehicles in California had already been established to be between 29-36% of total NOx emissions for the state, but this study determined that 20-32% of the state's NOx emissions came from cropland, a statistically significant increase from the California Air Resources Board (CARB)'s previous estimate that only 4% of the state's NOx emissions came from agricultural land. 

So how is agriculture such a culprit on NOx emissions? It isn't the emissions from the motorized farm equipment - it is the fertilizer! California's temperate climate leads to a year-round growing season in the Central Valley. As such, nitrogen rich fertilizer is applied multiple times a year for different crops grown in the crop rotation. However, as I already established, plants only take up so much of the fertilizer, and as this article and study cite, it has been estimated that with the current farming methods, only half of the nitrogen in the fertilizer is actually being taken up by the plants' root systems. That leaves the other half of the nitrogen in the soil. The other half is either digested by soil microbes and released as nitrogen oxide, NOx as cited in the article, or as this article demonstrates, the excess nitrogen makes its way as runoff to bodies of freshwater, wreaking havoc on the ecology of that body of water and coastline. When the soil microbes release NOx, it combines with light and other organic substances in the air to form ozone, which leads to global warming,. 

I think this is finding of fertilizer's contribution to NOx emissions is very important since it has also been repeated in the Midwest, America's "Bread Basket", where cropland there has been found to produce up to 40% of the Midwest's NOx during the summer months. This is a significant amount of ozone being produced by cropland.

In my mind, the fix is simple - farmers need to decrease the amount of NPK they apply to their acres of farmland and instead make sure the soil only receives the minerals it is already deficient in. This will reduce the toxic overload excess NPK has on the biology diversity of soil, to the formation of toxic algae blooms in freshwater lakes and ponds downstream of agricultural lands, and to the formation of ozone gases AND at the same time, it will increase the mineral and nutrient density of our food supply, which will improve our overall health and wellness.  

I think the biggest paradox of all is that the argument behind using copious amounts of fertilizer is that it helps farmers grow larger amounts of crops they can sell so that it can "feed more people" and yet the agricultural industry is also one of the largest contributors to throwing away excess food that wasn't able to be sold to the food processing plants, to the local markets, or donated to local food banks - and we still have hungry people living in our own communities, (for a review of this concept, I suggest watching the documentary Just Eat It). It's not really "feeding more people" to use copious amounts of fertilizer, it's just accelerating the destruction of our soil, water, and air, which in turn negatively affects our health and the health of the ecosystems we live in.

C.Yvonne Russell