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Nitrogen fertilizer

Story at-a-glance -

  • Applying an abundance of synthetic nitrogen fertilizer, year after year, to farmland is creating untold amounts of environmental damage
  • Marine dead zones (when oxygen concentrations fall below the level necessary to sustain most animal life) are one common consequence
  • Synthetic fertilizers destroy natural nitrogen found in the soil, which means farmers must use increasing amounts of the fertilizers each year just to sustain their yields
  • Synthetic fertilizers lead to the devastating destruction of organic matter in the soil

The New Nitrogen Bomb Is About to Blow

October 14, 2015 | 40,422 views

By Dr. Mercola

Plants need nitrogen to grow, and each year as crops are harvested, those ears of corn and apples pull nitrogen (and other nutrients) from the soil, leaving it depleted. In order to grow crops on the land again, nutrients, including nitrogen, must be added back into the soil.

Nitrogen is a bit of a conundrum because while it makes up 80 percent of the air around us, atmospheric nitrogen is unusable by plants. The form of nitrogen that plants use to grow is called nitrate, and, as Mother Jones reported, traditional agriculture techniques naturally help cycle usable nitrogen back into the soil:1

"… [F]or most of agriculture's 10,000-year-old history, the main challenge was figuring out how to cycle usable nitrogen back into the soil. Farmers of yore might not have known the chemistry, but they knew that composting crop waste, animal manure, and even human waste led to better harvests."

Then, in 1909, German chemist Fritz Haber developed a process to synthesize nitrate from the air. First nitrate was primarily used by the munitions industry during World War II (nitrate is explosive and was used to make nitrogen bombs).

In the post-war era, the use of nitrate shifted from munitions to fertilizer. The availability of synthetic fertilizer was instrumental in the shift from traditional to industrial farming, including the cultivation of new strains of corn that were reportedly "dependent on higher fertilizer applications."2 Mother Jones continued:

"Today, the United States remains a massive nitrogen-fertilizer user; with just 5 percent of the world's population, we consume about 12 percent of global nitrogen-fertilizer production. And corn — which according to the USDA 'requires the most nitrogen per acre' of any crop — remains at the center of our agriculture, covering 30 percent of farmland each year.

While our reliance on cheap nitrogen fertilizer occasionally (though quite rarely) results in attention-grabbing explosions, the real problems are more subtle and long-term."

The Environmental Toll of Synthetic Nitrogen Fertilizer Is Steep

Applying an abundance of synthetic nitrogen fertilizer, year after year, to our farmland is creating untold amounts of environmental damage. Marine dead zones (when oxygen concentrations fall below the level necessary to sustain most animal life) are one common consequence.

As fertilizer runs off of farms in major farming states (like Minnesota, Iowa, Illinois, Wisconsin, Missouri, and others), it enters the Mississippi River, leading to an overabundance of nutrients, including nitrogen and phosphorus, in the water. This, in turn, leads to the development of algal blooms, which alter the food chain and deplete oxygen, leading to dead zones.

One of the largest dead zones worldwide can be found in the Gulf of Mexico, beginning at the Mississippi River delta.3 Fisheries in the Gulf of Mexico have been destroyed as a result.

Then there is the nitrous oxide, a gas said to be 300 times more potent than carbon dioxide as a greenhouse gas and labeled "the world's most significant ozone-depleting substance."4

You can view the pervasiveness of nitrogen pollution in the Mississippi River Basin via this Ceres map. According to the non-profit organization GRAIN:5

"The [Intergovernmental] Panel on Climate Change (IPCC) estimates that for every 100 kg of nitrogen fertilizer applied to the soil, one kg ends up in the atmosphere as nitrous oxide (N2O)…

In 2014, this was equivalent to the average annual emissions of 72 million cars driven in the US
about a third of the US fleet of cars and trucks.

New research, however, shows that these alarming numbers are at least three to five times too low. The use of chemical fertilizers this year [2015] will likely generate more GHG [greenhouse gas] emissions than the total emissions from all of the cars and trucks driven in the US."

And here's another factor to consider: synthetic fertilizers destroy natural nitrogen found in the soil, which means farmers must use increasing amounts of the fertilizers each year just to sustain their yields.

It's estimated that in the last four decades, nitrogen fertilizer efficiency has decreased by two-thirds while their use per hectare of land has increased by seven times.6

Nitrogen application also pollutes water supplies. As noted by Christine Jones, PhD: "The USDA estimates that the cost of removing nitrate from U.S. drinking water is more than $4.8 billion per year…"7

Synthetic Nitrogen Fertilizer Leads to the Destruction of Organic Matter in Soil

Carbon is the main component of organic matter in soil, which is why organic matter is often referred to as a "carbon sink" (as opposed to a carbon source). It's estimated that one-third of the surplus carbon dioxide in the atmosphere stems from poor land-management processes that contribute to the loss of carbon, as carbon dioxide, from farmlands.8

Altering our agricultural practices in such a way as to return and confine organic matter and carbon in the soil, on the other hand, would help:

Regenerate the soilLimit agricultural water usage with no till and crop covers
Increase crop yieldsReduce the need for agricultural chemicals and additives, if not eliminate such need entirely in time
Reduce atmospheric carbon dioxide levelsReduce air and water pollution by lessening the need for herbicides, pesticides, and synthetic fertilizers

Unfortunately, in order to achieve these benefits, the use of synthetic nitrogen fertilizers would need to be drastically reduced, as they're one of the greatest threats to organic matter in the soil. GRAIN reported:9

"Despite industry propaganda to the contrary, recent studies demonstrate that chemical fertilizers are responsible for much of the massive loss of organic matter that has occurred in the world's soils since the pre-industrial era.

'In numerous publications spanning more than 100 years and a wide variety of cropping and tillage practices, we found consistent evidence of an organic carbon decline for fertilized soils throughout the world,' says University of Illinois soils scientist Charlie Boast.

Soils around the world have lost, on average, at least 1 to 2 percentage points of organic matter in the top 30 cm since chemical fertilizers began to be used.

This amounts to some 150,000 to 205,000 million tons of organic matter, which has resulted in 220,000 to 330,000 million tons of CO2 emitted into the air or 30 percent of the current excess CO2 in the atmosphere!"

As if this wasn't enough, the US fertilizer industry also relies heavily on natural gas extracted by hydrofracturing, or fracking – "the controversial process of extracting gas from rock formations by bombarding them with water spiked with toxic chemicals."10

"If Big Ag becomes hooked on cheap fracked gas to meet its fertilizer needs," Tom Philpott wrote in Mother Jones, "then the fossil fuel industry will have gained a powerful ally in its effort to pposition to fracking projects." 11

Fertilizer Overuse Boosts the Emissions of Microbes

Soil microbes convert nitrogen fertilizers into nitrous oxide, however it was long believed the nitrous oxide emissions would rise on a linear scale (for instance, doubling the fertilizer would double the emissions).

However, this linear model doesn't always hold up to real-world numbers, and research suggests the overuse of synthetic fertilizers may make emissions rise "exponentially."

When researchers analyzed more than 200 studies looking into the nitrous oxide emissions caused by multiple levels of fertilizer, excess fertilizer was found to boost the emissions of microbes significantly.12 Aside from its impact on soil microbes, the application of excess synthetic fertilizers alters the inter-dependency between natural nitrogen, carbon, and aggregation produced by soil fungi.

Mycorrhizal fungi use carbon to form soil aggregates, which is how soil structure is built. (More specifically, soil aggregates are produced by arbuscular mycorrhizal fungi.) Soil aggregates are like clusters of tiny particles that do not fit together, resulting in porous spaces in the soil. This alleviates compaction and allows for water retention.

As explained by Dr. Jones, if soils are not actively aggregating (due to a lack of mycorrhizal fungi), it will not fix significant amounts of atmospheric nitrogen, nor will it sequester stable forms of carbon.

The mycorrhizal fungi responsible for aggregation can be significantly harmed by agricultural chemicals and disruptive methods like tilling, both of which are cornerstones of our modern chemical-based agriculture. The use of diverse ground cover plants is also important for mycorrhizal fungi proliferation, and this is rarely done in conventional farming. She writes, in part:13

"When soil is bare there is no photosynthesis and very little biological activity. Bare soils lose carbon and nitrogen, nutrient cycles become dysfunctional, aggregates deteriorate, structure declines, and water-holding capacity is reduced.

Bare fallows, designed to store moisture and retain nutrients, become self-defeating. The maintenance of bare fallows - or the use of high rates of inorganic N [nitrogen] in crops or pastures — or worse, both — results in the uncoupling of the nitrogen and carbon cycles that have functioned synergistically for millennia."

Nitrogen Fertilizer as a Meth Magnet

Synthetic fertilizer is dangerous in ways you might not expect. Ammonium nitrate, for instance, is an explosive chemical. In 2013, a fire at a fertilizer plant in West, Texas killed 15 people and injured more than 160 others. But aside form the risk of explosion comes the risk of being targeted by those involved in the illegal manufacturing of methamphetamine (meth). Anhydrous ammonia, which is another type of nitrogen fertilizer, is a major ingredient in meth. The white tanks it's stored in dot farm fields across the US, making them prime targets.

Once siphoned from a holding tank, the liquid gas can be mixed with ephedrine and other ingredients to make the drug. Such thefts have leveled off now that ephedrine is not as readily available over-the-counter in pharmacies (as it was in the early '90s, when anhydrous theft peaked), but farmers still fear one day the thieves will forget to shut off a valve, allowing volatile anhydrous ammonia to seep out. As noted by Modern Farmer:14

"The fertilizer is loved as an efficient and cost-effective way to implant nitrogen into the soil, but it's loathed for being one of the nastiest treatments on the farm. Chemically, it's the same ammonia used in cleaners around the house, minus the water (thus, it is 'anhydrous'). The vapor is corrosive to human skin and aggressively seeks out water wherever it can find it, which means that anhydrous leaks can result in horrific injuries to the eyes, throat, sinuses, and lungs."

A Return to Biological Farming Is Urgently Needed

The use of synthetic fertilizers is clearly the next "nitrogen bomb" waiting to drop. Meanwhile, biological farming helps keep the planet healthy by naturally sequestering carbon in the soil and reducing, or eliminating, the need for chemical fertilizers. This includes such methods as cover cropping and ensuring nitrogen-fixing bacteria and other microbes are alive and well in the soil. National Geographic reported on one farm in west Iowa that's doing farming the "right" way:15

"Here 90 cattle graze on green pasture, and a few hundred pigs root about in beds of straw, surrounded by fields of alfalfa, corn, soybeans, oats, and barley. Ron and Maria Rosmann spread no nitrogen fertilizer on these fields, at least not the kind that comes from factories.

Instead, it's added biologically, by nitrogen-fixing bacteria that live in nodules on the roots of legume crops like soybeans, alfalfa, and a cover crop of clover that Ron Rosmann plants in the fall, only to till it back into the soil before he plants corn in the spring. Some of that nitrogen is captured in the corn, which he feeds to the pigs.

Most of that ends up in manure, which goes back onto his fields, and the cycle starts all over again. Rosmann, unlike many other organic farmers, doesn't buy manure from neighbors. 'One of our goals has been to maintain a closed system,' he says.

'We are a model for what organic farming should be like.'
We wade into one cornfield. The stalks tower over our heads. 'Look at this corn,' Rosmann exults. 'We could have 200-bushel corn right here. A lot of naysayers will say, You organic guys can't feed the world. I say, That's not true. Look at this crop!'"

National Geographic also described a research project in Michigan that has been ongoing for the past two decades. The project is part of Michigan State University's Kellogg Biological Station, near Kalamazoo. Here, fields that are exactly one hectare (about 2 1/2 acres) in size provide side-by-side comparisons of four different farming methods, ranging from conventional to organic. Everything that is added to or removed from each field is carefully measured, including rainfall, fertilizer, nitrous oxide, water that leaches into groundwater, and the harvest itself. According to the article:16

"Each field planted according to standard plowing and fertilizer recommendations released 610 pounds of nitrogen per acre into Michigan's shallow groundwater over the past 11 years... The organic fields in Robertson's experiment, which received no commercial fertilizer or manure, lost only a third as much — but those fields also produced 20 percent less grain.

Intriguingly, the 'low input' fields, which received small amounts of fertilizer but were also planted with winter cover crops, offered the best of both worlds: Average yields were about as high as those from the conventional fields, but nitrogen leaching was much reduced, almost to the level of the organic fields.

If America's farmers could cut their nitrogen losses to something close to this level... restored wetlands and revived small streams could clean up the rest… though, many farmers find it hard to change. When a family's livelihood is at stake, it may seem safer to apply too much fertilizer rather than too little."

'Agroecology' Is Common Sense

Last year, ecological farming — agricultural practices that protect, sustain, and regenerate the Earth's ecology — increased in popularity. Increasing numbers of farmers are indeed starting to recognize the value, if not necessity, for such modifications. Eco-farmers have also started getting increasing support from international organizations — the United Nations in particular. As noted by Olivier De Schutter, United Nations Special Rapporteur on the right to food:

"We cannot continue in this impasse of an oil dependent food production system. … Agroecology is really common sense. It means understanding how nature works, to replicate the natural workings of nature on farms in order to reduce dependency on external inputs."

The UN Food and Agriculture Organization (FAO) Director-General, José Graziano da Silva, has also said: "Agroecology continues to grow, both in science and in policies. It is an approach that will help to address the challenge of ending hunger and malnutrition in all its forms, in the context of the climate change adaptation needed."

At present, most governments around the world are subsidizing and/or promoting a food production system that is unsustainable. Moreover, it's done at the cost of both human and environmental health. Yet, research suggests a switch to sustainable agriculture could easily be done. According to GRAIN:17

"The elimination of chemical fertilizers is one of the easiest and most effective places to start. Cutting out chemical fertilizers could reduce annual global greenhouse emissions by as much as 10 percent… Additionally, the shift from chemical fertilizers to agroecological practices would allow farmers to rebuild organic matter in the world's soils, and thus capture a possible two-thirds of the current excess CO2 in the atmosphere within 50 years.

There are also the added benefits of improved livelihoods for farmers, more nutritious foods, protection of the ozone layer, and safe water systems. No technical hurdles stand in the way. Fertilizer companies may claim that if we stopped using their products we would have to plough up the earth's remaining forests in order to meet global food needs, but there are plenty of studies showing that farmers using simple agroecological practices can produce as much food without chemical fertilizers on the same amount of land."

Many organic farmers will tell you they are growing soil, not food — as properly cared for soil will take care of growing your food. As was expressed in the film, "Symphony of the Soil," all you need to do is "feed your soil compost and seeds." This is actually a key factor to look for when purchasing food. Seek to only purchase food grown by local farmers who are using natural methods and soil-regenerative techniques, such as no till, cover crops, composting, and livestock integration. This will naturally help you to eat better too, since typically only real whole foods are grown this way (while most processed foods are the product of destructive industrial agriculture).

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