Wednesday, February 29, 2012

The Nitrogen Cycle and You (and the garden, of course)

Nitrogen is the building block for proteins, and proteins are the building blocks for you. They are what make the muscles and tendons in your body. The surprising part about this is that a large portion of the nitrogen in your body was created in a factory somewhere.

At these factories, nitrogen is pulled out of the atmosphere and turned into a biologically useful form for one main reason: fertilizer. Normally, nitrogen is slowly pulled from the atmosphere by bacterial communities in the soil. Since, bacteria do not do this very quickly so nitrogen is the most common deficiency in agricultural soil. Therefore, in most fields, you can spray anhydrous ammonia (pure nitrogen fertilizer) into the soil and suddenly your plants are bigger, much much bigger. So when you look at the fertilizers used on most farms, the backbone is anhydrous ammonia. When I went to college in Iowa, tanks of anhydrous ammonia were everywhere.
Most researchers conclude that this fertilizer causes enough of a boost in agricultural crops that this technology alone is supporting around one third of the population of the Earth. In fact, just before the year 2000, a group of scientists sat down to determine the most important invention of the last 100 years. Their pick for this award was the poorly known Haber-Bosch Process. This is the method that is used to create anhydrous ammonia.

Impressive, right? As with most amazing, world-changing technologies, this one has it's costs as well. Approximately 2% of the worlds energy goes to the process that makes anhydrous ammonia. At this point you might be thinking, "2% is a lot of energy, but it seems like a fair trade seeing as 33% of the world's populations is alive because of it." Quite true, however, there is another drawback to this fertilizer. It is so potent that it is being overused. If you are a farmer, it makes sense that you might want to add just a little extra in case your math is a little off. After all, it is just one farmer adding just a little bit extra. Right? The problem with this is when most farmers in the US decide to do this:

Above is a picture of the Gulf of Mexico near the Louisiana coast where the Mississippi goes out to sea. Notice all of the green near the coasts? Unfortunately, that is what happens when a little bit extra fertilizer from each farm in the Midwest washes downstream. Once this stream of nitrogen loaded water hits the warm waters in the gulf, it causes massive algae blooms. The algae blooms overwhelm the existing ecosystem, causing a massive drop in productivity for fish. These have been nicknamed "dead zones" and are increasingly common around the world.

So it seems that all of this crucial nitrogen fertilizer is costly to create and costly to dispose of. Therefore, we at the garden have attempted to do our part by looking to other places to get our nitrogen boost. We do this by recycling.
The word recycling probably brings to mind the tin cans and plastic bottles that you separate from your garbage every day. At the garden, we use the same concept. The only difference is that instead of reusing plastics and metals that are costly to create, we reuse nitrogen that has been costly to create. It seems like a waste to ignore all the nitrogen that society throws away. How do we do this?

As a society, we throw away this fertility through food waste. Up to a third of food in the United States is tossed out. This could be everything from your orange peel to the lasagna that was hiding in the back corner of your fridge (eww). Although these are everyday examples, a large percentage is also lost before it reaches the consumer. Imagine the warehouse worker who forgot that pallet of lasagna in the corner of the warehouse (big eww).
That is where we come in. Whenever food gets a little funky at the food bank, we take it off their hands and save Tempe Community Action Agency the work of having it hauled away. (Also, if you have any food scraps around the neighborhood, feel free to bring them in.)
At the garden we have a nice little ecosystem based on these food scraps. Mostly, we let bacteria and soil organisms like worms turn the food back to soil (composting). However, we recently have added a new level of productivity. Since the microbes don't really give us anything in exchange for the free food we are giving them, we bought some chickens. These ladies chow down on all of the vegetables they can get their beaks into, and in exchange have started laying eggs for us. Also, being birds, chickens have manure that is highly concentrated in nitrogen, which means less shoveling for us to get our nitrogen fertilizer to our plants.
It is not going to fix the dead zone, but we decided the chickens are much more entertaining than keeping a tank of ammonia around the garden.

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