Field Measurements of Denitrification From Fertilizer Applied to Turfgrass

Denitrification and mass balance measurements of fertilizer N applied to turf was studied under field and greenhouse conditions. Highly enriched 15N-labeled KNO3 or urea was applied to replicated plots on a Flanagan silt loam soil under Kentucky bluegrass (Poa pratensis L.) or creeping bentrgrass (Agrostis palustris Huds). Atmospheric samples were collected daily (data extrapolated to a 24-h period) for the duration of each experiment and analyzed by mass spectrometric procedures. Data reported indicate that labeled fertilizer N losses from Kentucky bluegrass turf ranged from 3.3 to 21.3% for N2 and from 0.3 to 5.9% for N2O; that large N2 and N2O fluxes occurred after heavy rainfall events; and that more N2 was evolved than N2O; Bare soil plots consistently led to smaller emission rates of N2 or N2O when compared to turf. Evolution of total N and labeled fertilizer N was greater for KNO3 than for urea through the first three wk of an experiment comparing effects of fertilizer source on atmospheric emission of N2 and N2O from creeping bentgrass, and emission was greater for urea during the last two wk of the experiment. Upon completion of the Kentucky bluegrass experiments, sampling cylinders were removed, and the plant, soil, and leachate samples were analyzed for 15N by mass spectrometry. Recovery of labeled fertilizer N ranged from 57.4 to 73.2% for turf and averaged 84.2% for bare soil. Complete recovery was observed from bare soil, 100.2 +/- 1.9%, and for turf, 98.7 +/- 9.6%, during an experiment to verify the methods employed could completely recover labeled fertilizer N within 24 h after the fertilizer application.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Horticulture

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2015

Author dc:creator

• Horgan, Brian Patrick

Contributors dc:contributor

• Branham, Bruce E.
• Mulvaney, Richard L.

• Agriculture, Agronomy

Language dc:language

eng

Identifier

(MiAaPQ)AAI3017104

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/87822