I was thinking about other approaches to wards supply of nitrogen to the plant other then using urea, so what form of nitrogen will be best for plants?

And also if we just pass the atmospheric N2 (of course along with other gases which being present in the atmosphere) in to the soil by mean of some mechanism be any help?

1 Answer 1


The best form of nitrogen for plants is compost. It's among the least concentrated forms of "nitrogen as fertilizer" and that's a good thing, as concentrated nitrogen is not a normal thing in healthy soils, and it is bad for the complex life that makes up a healthy soil, which results in healthy plants.

Where "some means" of passing nitrogen into the soil is to plant legumes inoculated with nitrogen-fixing bacteria it works out well. Article from nature communications

Nitrogen gas is not biologically available to plants, so putting it in the soil (which already has it, as air fills the pore spaces of soils) does not do anything useful.

The direction that urea-using folks tend to go when looking for "more" is injecting anhydrous ammonia (NH3) which is biologically available to plants, but both are also toxic to much of the microbiota in the soil, and they can also be toxic to plants. The former effect tends to mean that soils fertilized this way once will need to be fertilized this way ever after unless some time can be taken to repair them, as their natural productivity from the healthy microbiome is severely damaged and takes at least several years to recover, during which productivity is low.

  • I call those chemically managed fields 'in ground hydroponics'.
    – MackM
    Commented Apr 11 at 21:31
  • Concentrated form of nitrogen is found in nature. Some plant can cope with it, but often it is not what we want. Sorry to use such words, but sheet, piss, and corpses will kill some vegetable, but overgrowth others. I do not recommend the first two in gardens ;-) -- And you miss the usual it depends. Each plant is different. Some orchids may not use roots to get N, carnivorous plants also may have different preferences (and so this comments will be flagged because of keywords ;-) ). Commented Apr 15 at 13:31

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