Dear Colleagues. I am conducting a scoping study on the advantages and disadvantages of using anhydrous ammonia as a soil-applied source of nitrogen for vegetable and other crop plants. I would be extremely grateful for any comments, experiences or references that anyone may care to share. I will be conducting a literature search and survey, but one aspect I hope to bring into this discussion is the practical experience ("anecdotal evidence?) of people who have used this material. As someone keenly interested in the interrelationship of the three soil properties: physical; chemical and especially biological, my inclination to date has been to dismiss any possibility of using this material. I am now looking to reassess this view. I would like to thank The Reader, and anyone kind enough to respond in advance. With warmest and best wishes. Andrew Krajewski Ph.D. Albany, Western Australia.
Dear Andrew,
Anhydrous NH3 contains 82% N. the highest amount of any N fertilizer. In some respects NH3 behaves like water, since they both have solid, liquid, and gaseous states. Anhydrous ammonia is an efficient and widely used source of nitrogen fertilizer. Anhydrous ammonia has several advantages, including its relatively easy application and ready availability. effectiveness as nitrogen fertilizer source: Most research shows that nitrogen supplied as NH3 is used by crops as effectively as nitrogen from any other source.
However, there are also disadvantages and potential dangers involved in handling anhydrous ammonia. It must be stored and handled under high pressure, requiring specially designed and well-maintained equipment. In addition, to ensure their safety, workers must be adequately educated about the procedures and personal protective equipment required to safely handle this product. If the NH3 tank is pulled behind the air tank of an air seeder, the main delivery hose must have safety break-away couplers at both the rear of the air tank and the rear of the seed drill. Safety chains must also be in place to prevent the loss of control in the event of hitch pin loss.
NH3 Safety Issues
NH3 is a hazardous substance. Personal contact with NH3 is dangerous at any concentration.
Safety protection and first aid
1. Always wear safety apparel including eye protection when working on or around NH3 equipment. The eyes are the part of the body most sensitive to NH3damage. Eyes have few blood vessels for cooling and very little water, and they do not grow new tissue readily.
2. You can smell NH3 at a concentration of 50 parts per million (ppm). It has sharp, pungent odour. It is safe up to 100 ppm for several hours. At 400 ppm, the eyes are irritated and exposure should be avoided.
3. Contact with liquid NH3 is the most common accident. The liquid causes a caustic burn from its chemical makeup and a freeze burn as it absorbs water from the skin (the word "anhydrous" means it seeks water).
4. Flooding the exposed parts with water is the most immediate need and, in fact, the only first aid needed until full medical attention is received.
5. If liquid is spilled, do not remove clothing until flooded with water. The frozen cloth may tear away the flesh.
Safe operation of NH3 systems
1. Ensure the NH3 system is correctly designed, assembled and regularly maintained
2. Always use a pressure tank tested to 250 psig to hold NH3, not an LPG tank!
3. Turn the equipment and stay upwind if a leak occurs.
4. Any coupling between air drills, air tanks and the nurse tank needs to be protected by safety chains, locking draw pins and safety break-away fittings.
5. Do not bend hoses, tighten fittings or separate connectors when under pressure.
6. Drain all hoses and lines, including the line at the ground opener, before working on any part of the NH3 system. Make sure they are empty. If a plugged NH3 line is removed from the opener, it can spit out liquid NH3
7. Know the correct sequence to open and close valves to purge the system of NH3. Rate controllers have special purge controls.
8. Remember that NH3 vapour is combustible if it is 16 to 25 per cent by volume in air and has an ignition source.
9. Take a course - and include your helpers - on safe handling of NH3.
Regards,
Prem Baboo
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