A field study was conducted at Mandan, North Dakota to provide information on the fate of fertilizer nitrogen (N) in a Northern Great Plains rangeland ecosystem. Mixed prairie grasses were fertilized with up to 540 kg N/ha applied (a) all in one year, (b) divided equally among 3 years, or (c) divided equally among 6 years. Up to 200 kg fertilizer N/ha was immobilized the first year in grass roots, soil organic matter, and fixed ammonium combined, plus gaseous losses (no leaching occurred). Immobilization and losses increased to about 350 kg fertilizer N/ha after 3 to 4 years, and remained rather constant thereafter. About half the immobilized N was found in the grass roots at the termination of the experiment. Collectively these results indicate that addition of high N rates to grasslands results in saturating the capacity of the soil-plant system to immobilize N. The system can then be maintained in an N-saturated condition if annual fertilizer additions plus mineralization equals immobilization plus irreversible losses. Thus, N can be eliminated as a growth-limiting factor, providing maximum grass production from the available water supply. This material was digitized as part of a cooperative project between the Society for Range Management and the University of Arizona Libraries. The Journal of Range Management archives are made available by the Society for Range Management and the University of Arizona Libraries. Contact lbry-journals@email.arizona.edu for further information. Migrated from OJS platform August 2020
Scholarly peer-reviewed articles published by the Society for Range Management. Access articles on a rolling-window basis from vol. 1, 1948 up to 5 years from the current year. Formerly Journal of Range Management (JRM). More recent content is available by subscription from SRM.