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System for Preparing and Applying 15 N‐Labeled Anhydrous Ammonia in Field Plot Research
Author(s) -
Griesheim K.L.,
Mulvaney R.L.,
Smith T.J.
Publication year - 2019
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj2018.10.0366
Subject(s) - anhydrous , ammonia , chemistry , nitrogen , dilution , fertilizer , analytical chemistry (journal) , chromatography , organic chemistry , physics , thermodynamics
Core Ideas A manifold is described for preparing kilogram quantities of 15 NH 3 . The 15 NH 3 is condensed into a collection tank that allows the use of a nitrification inhibitor. The collection tank connects to a tractor‐mounted toolbar for knifed applications to field plots. Although direct application of anhydrous ammonia (NH 3 ) is a common practice for Midwestern corn ( Zea mays L.) production in the USA, field studies utilizing 15 N 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 NH 3 from labeled and unlabeled sources to obtain a desired 15 N 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% 15 N were obtained for 3 kg of NH 3 prepared within a normal working day by a 15‐fold dilution with 10 atom% 15 N 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 NH 3 .