Nitrogen Tracers in Nitrogen Cycle Studies—Past Use and Future Needs1
- Roland D. Hauck2
Nitrogen research is directed toward two main objectives, food and fiber production and environmental control. To achieve N balance in productive ecosystems, better quantitative estimates of N transformation rates are needed. Nitrogen tracers are indispensable for making many of these estimates. Either 15N-depleted or 15N-enriched materials can be used. The use of 15N-depleted materials is limited to studies where dilution form other N is less than 2,000-fold, but these materials are potentially available in ton amounts.
Use of variation in natural 15N abundance may be useful in observing qualitative relationships among N cycle processes over large areas or extremely long time periods. Such use is questionable for obtaining quantitative information for short-term N transformation processes.
Obvious information gaps are quantitative data on atmospheric N2 fixation and denitrification in cropped field soils and N transformation data for many other ecosystems. A program for computer data retrieval and correlation is outlined.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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