It is estimated that humans have doubled the rate of nitrogen input into the nitrogen cycle, mostly since 1975.

Production techniques (e.g., irrigation management, recommended nitrogen inputs)

They note that this nitrogen input in the Gulf of Maine is "more than the input of all rivers combined", some 23,000 metric tons each year.

Nitrogen balance is the measure of nitrogen input with the nitrogen output subtracted from it.

Now, after a half-century of accelerated nitrogen input (much of it from direct atmospheric deposition), the lake is phosphorus-limited.

Agricultural and industrial nitrogen (N) inputs to the environment currently exceed inputs from natural N fixation.

This relationship appears to be mutualistic, with the plant providing shelter for the bats and in return receiving additional nitrogen input in the form of faeces.

Anthropogenic nitrogen inputs account for about 80% of all nitrogen fluxes in ecosystems.

The genus has also been utilized as a nitrogen input into low input or organic cropping systems.

Other studies were done to show excessive nitrogen input from discharges of the Pearl River Delta into the harbour for decades.