Fixing Nitrogen: Why Synthetic Fertilizer Isn’t Necessary
Tomorrow it will be March and that means, in many parts of the country, the call will go out: Ready . . . Set . . . Fertilize. Whether we’re planning tomatoes or a lush green lawn, our nature is to help Mother Nature by adding a bunch of stuff to the soil that we’ve been led to believe we need.
Have you ever considered the radical idea that fertilizer isn’t needed? At least not much anyway? And never, ever, synthetic fertilizer? One of my recent posts talked about the origin of synthetic nitrogen fertilizer (http://www.safelawns.org/blog/index.php/2010/02/high-irony-afghan-war-seen-as-boon-to-organics/) and how dangerous and wasteful it can be.
Our here in Los Angeles for today’s premiere of A Chemical Reaction I’m staying at a home where the lawn hasn’t had fertilizer applied in years, but it’s still lush and green. How is that possible? It’s easy, really, because the lawn has an ample amount of clover, which is a nitrogen-fixing plant. That means this lawn is making its own fertilizer.
I’m not saying fertilizer is NEVER needed. Some annual plants like tomatoes are heavy feeders and will benefit from frequent feedings or organic fertilizers if the soil isn’t really, really rich to begin with. Likewise, a lawn may need some food to help it become thick and lush. The difference between synthetic chemical fertilizer and organic fertilizer is that the synthetic stuff feeds the plants directly, yet tests show that much of the material is wasted through run-off and vaporizing. With organic fertilizers, you’re actually applying materials that feed the soil organisms. When the soil organisms consumer the organic foods, they digest and excrete the foods to create natural fertilization.
Here’s an excerpt from my book, The Organic Lawn Care Manual, that explains the process:
All living things need the element known as nitrogen. An atom of nitrogen lies at the heart of all amino acids and DNA in animals and all photosynthesis in plants. Since nitrogen gas comprises about 78 percent of the Earth’s atmosphere, you might think we should have plenty of nitrogen anytime we need it. Much of that atmospheric nitrogen, however, is inactive or “inert.” How we convert that nitrogen into a form available to grow our grass plants is one of the primary differences between synthetic and natural lawn care.
Nitrogen fixing is defined as any natural or industrial process that causes nitrogen gas to combine with other elements to form useful nitrogen compounds — typically known as ammonia, nitrates, or nitrites.
Early in the last century, two scientists named Fritz Haber and Carl Bosch blended two emerging technologies to spawn the modern synthetic fertilizer industry. By combining nitrogen with hydrogen under extremely high pressures and temperatures, the result was nitrogen compounds that could be used as fertilizers. Creating these temperatures and pressures requires the burning of large amounts of fossil fuels, usually natural gas, to achieve the 750 to 1,200 degrees Fahrenheit required for the nitrogen conversion. Though the Haber-Bosch process is still considered to be the most commercially economical for the fixation of synthetic nitrogen, some scientists have pointed to the “hidden” cost of burning all that fossil fuel in the process.
Dr. David Pimentel
of Cornell University estimated it takes about 33,000 cubic feet of natural gas to create one ton of nitrogen, enough for about 150 of those 40-pound bags of 32-10-18 fertilizer. That’s enough natural gas to heat the average American home for half a year. That’s why every time home fuel prices increase, fertilizer prices typically follow suit.
Nature, of course, has its own methods of fixing nitrogen. One, interestingly, is through the occurrence of lightening. If you have ever been close to a lightening strike and smelled ammonia afterward, you were actually getting a whiff of nitrogen fixation. The other more prevalent method of fixing nitrogen is through special microorganisms that live in soil and water. These invisible creatures ingest nitrogen sources in the soil and this, in turn, allows the nitrogen to be used by the plants.
Many plants, known as legumes, are said to feed this nitrogen fixation process. By taking nitrogen from the atmosphere and attaching it to their roots in bag-like nodules, plants such as peas, beans, clovers and vetches become nitrogen warehouses for the soil. When the bacteria eat this stored nitrogen, the other plants’ roots can then have access to the nitrogen. The term for this is nitrogen cycling; every time you add compost to the soil, or apply a natural fertilizer to the soil — rather than a synthetic fertilizer for the plants — you’re supporting nitrogen cycling. Synthetic fertilizers not only bypass these amazing processes, they often harm them by killing the many of the microorganisms involved.