[dennis]

Edward, to be a stickler for details, I'm not sure if that statement is quite right. NO3 is NO3 regardless of organic or inorganic. The plants would have to expend the same amount of energy to get the N from either kind. In this hobby, I think people get confused as to what is N and what is NO3 (not saying you are Edward). As far as I know, a test kit will measure N and if it is made to "measure" NO3 then the chart or code will automatically have converted to the proper level of NO3 by multiplying by the correct proportionality factor. Same goes for NO2. This is not entirely true if you get very expensive and technical, but most hobby grade kits will not have the technology associated to measure NO3 as a specific ion but will measure N and convert.

Now as far as the source of N is concerned, organic N will most likely be harder for the plant to get because the N will be bound to more complex organic forms like acids, etc. For examlpe, put KNO3 in water and you get K+ and NO3-. The NO3- ion is more available the a NO3 ion that was created organically and may be bound to (for example) H, as in nitrous acid- HNO3. The plants will have to work harder to strip the N from that molecule than they would to strip the N from NO3inorganic.

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