The fossil fuel-intensive Haber-Bosch process, developed in the early 1900s by Fritz Haber and later modified for commercial production by Carl Bosch, uses natural gas to turn atmospheric nitrogen into ammonia to make nitrogen (N) fertilizers. Industrial agriculture uses N fertilizers to grow crops without manure from livestock, a process that has adversely affected food chains globally. During the past century, the use of synthetic N fertilizers has increased 20-fold while the nutrient content of produce in supermarkets has dropped by 10-50%. Research in New Zealand shows that an excess of 45 kg N-unit/ha adversely impacts the return/cost/quality ratio of crop and feed production. Applications of 200 kg N unit /ha are common in the U.S. Midwest and many other industrial countries. 

Contrary to the popular belief that the green revolution increased human health, wealth and populations, the increased yields from synthetic fertilizers in agriculture have caused many problems, which took time to manifest and accept. Use of synthetic N fertilizers has a major negative impact on the sustainability of soil, air, and water and the health of livestock and humans. The inability to use groundwater in some agricultural areas is mostly (approx. 70%) due to nitrates from synthetic N fertilizers. Ground water pollution by nitrates, and excessive nitrates in lettuce, are the tip of the iceberg. The chernozem soils of the Midwest U.S. lost 40% of their organic matter, which volatilized into GHG. Overuse of N fertilizers is a major concern for GHG: nitrous oxide (N₂O) has a GWP 273 times that of CO₂ for a 100-year timescale. Nitrogen fertilizer production uses large amounts of natural gas and some coal and can account for more than 50% of total energy use in commercial agriculture. Human health, especially in the U.S., is also affected. Record high yields of crops, only possible with synthetic N fertilizers, reduce nutrient content of grains:  80-90% of calories in the fast-food chains are provided by corn and soy. Most of the feed for livestock is also corn and soy. Low nutrient content in grain causes livestock and humans to overingest foods in a futile attempt to meet needs for nutrients in low concentrations.

Currently, in the United States only 4% of beef calves spend their entire lives eating phytochemically rich mixes of plants on pastures and rangelands where they were born and raised. The other 96% of calves are weaned, sold, and fattened in feedlots, under conditions that violate freedoms of animal welfare. They are moved from familiar to unfamiliar locations, which causes fear and distress. They dislike any food eaten too often or in excess, yet they are fed daily the same ration so high in grain they experience nausea which causes food aversions, stress, and distress. Though individuals differ in preferences, they can’t self-select their diets, which violates their freedom to express normal behavior and avert distress and disease. These practices cause livestock to suffer various maladies, including chronic acidosis, oxidative and physiological stress, and other metabolic diseases not unlike people with metabolic syndrome, which is characterized by muscle mitochondrial dysfunction, oxidative stress, and elevated levels of cortisol, blood glucose, and insulin. Livestock and people are sustained by the medical and pharmaceutical industries to counter horrific diets, lack of exercise, and stress. 

Conversely, due to their phytochemically rich diets and higher levels of physical activity, animals born, raised, and finished on farmlands and rangelands with diverse mixes of plant species have improved metabolic health. Their meat has higher levels of compounds that improve the health of livestock and humans, including polyphenols, tocopherols, carotene, and omega-3 fatty acids to name but a few.

Introducing livestock back into farming would eliminate the need for synthetic fertilizers, recreate a healthy nitrogen cycle, and reduce pollution from concentrated livestock feeding operations. These practices in the U.S. use 80% of antibiotics (70% medically important). Europe’s use of antibiotics for livestock is about half that in the U.S.  By consuming animal products (meat/dairy) that have been under regular prophylactic antibiotic treatment, as well as the increase of resistance of bacteria to antibiotics in livestock, and thus humans, the efficiency of antibiotics for human medical treatment is reduced.  Incorporating livestock into farming practices, and reducing N fertilizers, would improve the health of livestock, humans, and the environment; provide more nutrient-dense foods; regenerate agricultural soils; and reduce water contamination from nitrates.