Degree Type

Dissertation

Date of Award

1984

Degree Name

Doctor of Philosophy

Department

Agronomy

Abstract

Field studies of the effects of different N fertilizers on emission of N(,2)O from three Iowa soils showed that the N(,2)O emissions induced by application of 180 kg ha('-1) of fertilizer N as anhydrous ammonia greatly exceeded those induced by application of the same amount of fertilizer N as aqueous ammonia or urea. On the average, the emission of N(,2)O-N induced by anhydrous ammonia was more than 13 times that induced by aqueous ammonia or urea and represented 1.2% of the anhydrous ammonia N applied. This confirms indications from previous work that anhydrous ammonia has a much greater effect on emission of N(,2)O from soils than do other commonly used fertilizers. Laboratory studies of the effect of different amounts of NH(,4)OH on emission of N(,2)O from Webster soil indicated that the exceptionally large emissions of N(,2)O induced by fertilization of soil with anhydrous ammonia are due, at least in part, to the fact that the customary method of applying this fertilizer by injection into soil produces highly alkaline soil zones of high ammonium-N concentration;Field experiments to determine the effects of rate and depth of fertilizer application on emission of N(,2)O from soil fertilized with anhydrous ammonia showed that the fertilizer-induced emission of N(,2)O-N in 116 days increased from 1.22 to 4.09 kg N(,2)O-N ha('-1) as the rate of anhydrous ammonia application increased from 75 to 450 kg N ha('-1), and that a 100% increase in the rate of anhydrous ammonia application led to a 60% increase in the emission of N(,2)O. These experiments also showed that the emission of N(,2)O-N induced by injection of anhydrous ammonia at a depth of 30 cm was greater than that induced by injection of the same amount of anhydrous ammonia N at a depth of 10 or 20 cm;Field studies showed that the N(,2)O emissions induced by fall or spring fertilization of soil with anhydrous ammonia (180 kg N ha('-1)) were markedly reduced by addition of a nitrification inhibitor (nitrapyrin) at the rate of 0.56 kg ha('-1) and indicated that nitrapyrin (N-Serve) has potential value for reduction of the N(,2)O emissions induced by N fertilization of soils and the possible adverse effects of these emissions on our climate.

DOI

https://doi.org/10.31274/rtd-180813-5382

Publisher

Digital Repository @ Iowa State University, http://lib.dr.iastate.edu/

Copyright Owner

Gary A. Breitenbeck

Language

en

Proquest ID

AAI8423694

File Format

application/pdf

File Size

69 pages

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