Nitrogen,a major limitation in the productivity of natural communities,crops and pastures in the pacific area

Various aspects of the nitrogen cycle are reviewed as a background for discussion of nitrogen balance and economy in plant communities. Even though fixation of atmospheric nitrogen generally exceeds losses of nitrogen from the biosphere it is pointed out that plants extract nitrogen from the soil faster than it can be mineralized from organic forms. This difference in rates leads to a nitrogen deficiency in plants, particularly in high yielding crop plants, and subsequently a protein deficiency in animals.Some facets of legume bacteriology are discussed also. In particular the introduction of legumes to new areas and the need for inoculation of seed with specific Rhizobium strains, importance of strain selection, testing and supply, legume inoculant quality and seed inoculation and pelleting.