System for preparing and applying15N-labeled anhydrous ammonia in field plot research

K. L. Griesheim, R. L. Mulvaney, T. J. Smith

Research output: Contribution to journalArticlepeer-review


Although direct application of anhydrous ammonia (NH3) is a common practice for Midwestern corn (Zea mays L.) production in the USA, field studies utilizing 15N to quantify nitrogen (N) uptake efficiency have long been impeded by the difficulties and safety hazards inherent to a liquified gas that must be handled and applied under pressure. A manifold system is described for transferring known quantities of NH3 from labeled and unlabeled sources to obtain a desired 15N enrichment, and for collecting the mixture cryogenically in a tank specifically configured for knifed applications using a tractor-mounted tool bar. Enrichments of 1.2 to 1.5 atom% 15N were obtained for 3 kg of NH3 prepared within a normal working day by a 15-fold dilution with 10 atom% 15N as the starting label. A collection capacity of such magnitude represents a 3000% upscaling over systems previously described for this purpose, providing an essential prerequisite for field plot research to realistically assess the fate and fertilizer value of anhydrous NH3

Original languageEnglish (US)
Pages (from-to)475-482
Number of pages8
JournalSoil Science Society of America Journal
Issue number2
StatePublished - Apr 4 2019

ASJC Scopus subject areas

  • Soil Science


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