MadSci Network: Agricultural Sciences |
Nitrogen gas surrounds us all, yet we barely notice this benign compound exists (78% of the atmosphere is composed of nitrogen gas, N2). However, when combined with other elements, nitrogen can have a very schizophrenic personality. Nitrogen compounds can be used to feed, or kill, with equal ease. This ironic nature of nitrogen was tragically demonstrated in the Oklahoma City Bombing when fertilizer was used as an explosive, killing hundreds All living things require nitrogen to live (it is the "amino" in "amino acids", a major component in DNA, RNA, and proteins) however few creatures can make direct use of the sea of nitrogen surrounding us all. This is because the two nitrogen atoms that make up a nitrogen molecule are held firmly together by a triple bond which is exceedingly difficult to break. Because of this bond, nitrogen gas simply does not participate in any reactions at room temperature (or even at the higher temperatures found in small fires), and is therefore described as inert. Only at extremely high temperatures (such as those found near a lightning bolt or in an automobile's engine), or through the magic of "nitrogen fixing" bacteria (who work their trick with a complex set of enzymes instead of heat), can this triple bond energy be overcome, making nitrogen gas momentarily reactive while in an excited state. If this excited nitrogen molecule is combined with oxygen (which incidentally composes the rest of the atmosphere) nitrogen oxide (NO) is produced. This readily oxidizes to nitrogen dioxide (NO2), which provides the brownish haze seen in smog (as all Los Angeles residents are well aware). If, on the other hand, the excited nitrogen gas combines with hydrogen, it forms ammonia (NH3). And ammonia, unlike smog, is a very useful compound indeed. It can be used to make fertilizers, high explosives, nitric acid, and household cleaning agents. Converting nitrogen gas into more reactive (and useful) nitrogen compounds, such as ammonia, encompasses the first stage in the "nitrogen cycle". Once converted from its gaseous form, fixed nitrogen compounds allow plants to grow large and healthy. Animals gain access to this nitrogen by eating the plants, and deposit excess nitrogen in their feces. Fixed nitrogen is also returned to the soil when plants and animals die. Bacteria then decompose this organic matter first into ammonia, then into nitrites (like potassium nitrite: KNO2), and finally into nitrates (like potassium nitrate: KNO3), which are again used by plants. Additional bacteria return some of the fixed nitrogen back to the atmosphere (in the form of nitrogen gas), thereby regulating the whole cycle Now that I backgrounded you to death...Nitrogen is obtained commercially primarily by membrane separaters. This is not something one could easily or more importantly..cheaply do at home. Even if you did get your Nitrogen gas then you would as explained above convert it to a form that can be utilized by plants which entails many other processes. Its just a lot cheaper and easier to contact a local stable and tell them you would like to remove their manure. You will get free fertilizer and make a friend too......Mark
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