There is no doubt that nitrogen boosts plant growth and of course growth is nothing more than cell production. As new cells form, they look for calcium to help with cell structure and if they cannot find it they take up water instead.
This is why grass generated by heavy applications of urea has no strength and is watery, producing watery excrement. Crops will be the same and drying them out will show this as their size shrinks more than it should.
As a result animals and humans need to eat more of this kind of growth to get the same levels of goodness contained in non-N boosted plants.
Urea is also notoriously short acting and by the end of a week, it has gone from the soil and what plants could not take up has been lost to the waterways and atmosphere. Nitrogen, along with potassium, is water soluble and easily washed out of the soil.
In addition to polluting waterways, farm emissions of nitrous oxide – a greenhouse gas much more potent that carbon dioxide – account for about a sixth of national emissions, twice as much as produced by all the gas and coal burned in power stations. Agricultural gases, which are about two-thirds methane and one-third nitrous oxide, are just under half New Zealand’s emissions.
Perhaps the most dramatic impact of humic acid is on urea because it will hold and slow release the nitrogen, leading to much higher (greater than 40%) dry matter and MORE volume. You can either reduce the amount of urea you apply or get more production from your current application.