"не нашла в гугле" ?
если поместить в строку поиска - "Environmental Impact" "P and N control"
получаем сразу же ссылку на документ -Managing Phosphorus for Agriculture and the Environment ...
extension.psu.edu/.../managing-phosphorus-for-agriculture-... в котором -
"....Phosphorus (P) is an essential element for plant and animal growth ........ Nitrogen (N) and P both affect eutrophication, but P is the critical element in most fresh waters. Where water salinity increases, as in estuaries, N generally controls aquatic plant growth.....
| 