NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
Terrestrial nitrogen cycles: Some unanswered questionsNitrogen is generally considered to be the element which most often limits the growth of plants in both natural and agricultural ecosystems. It regulates plant growth because photosynthetic rates are strongly dependent on the concentration of nitrogen in leaves, and because relatively large mounts of protein are required for cell division and growth. Yet nitrogen is abundant in the biosphere - the well-mixed pool in the atmosphere is considered inexhaustible compared to biotic demand, and the amount of already fixed organic nitrogen in soils far exceeds annual plant uptake in terrestrial ecosystems. In regions where natural vegetation is not nitrogen limited, continuous cultivation induces nitrogen deficiency. Nitrogen loss from cultivated lands is more rapid than that of other elements, and nitrogen fertilization is generally required to maintain crop yield under any continuous system. The pervasiveness of nitrogen deficiency in many natural and most managed sites is discussed.
Document ID
19850005883
Acquisition Source
Legacy CDMS
Document Type
Other
Authors
Vitousek, P.
(Stanford Univ. CA, United States)
Date Acquired
August 12, 2013
Publication Date
January 15, 1984
Publication Information
Publication: JPL The interaction of Global Biochemical Cycles
Subject Category
Environment Pollution
Accession Number
85N14192
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

Available Downloads

There are no available downloads for this record.
No Preview Available