New Zealand Journal of Agricultural Research abstracts
Short communication
Grassland soil microbial respiration responses to urea and litter
applications
F. M. Kelliher1
J. R. Sedcole2
I. Emery3
L. M. Condron2
1Manaaki Whenua - Landcare Research
PO Box 40
Lincoln 7640, New Zealand
kelliherf@landcareresearch.co.nz
2Agriculture and Life Sciences
PO Box 84
Lincoln University
Canterbury 8150, New Zealand
3University of Washington
School of Medicine
Box 357710, Seattle
WA 98195-7710, USA
Abstract Ground ryegrass (Lolium perenne
L., 5300 kg C ha–1, 12 g C kg–1 (soil))
and urea were applied to a grassland soil with the same dose of
nitrogen (N), 500 kg N ha–1, 1.1 g N kg–1 soil,
and microbial respiration responses measured in the laboratory.
Microbial respiration rate in control, ryegrass- and urea-amended soil
averaged 2.1 ± 0.2, 25.0 ± 1.7 and 10.6 ± 0.7
µg
CO2 kg–1 soil s–1, 1.5 h after
treatment applications. Microbial respiration rates in ryegrass- and
urea-amended soil were significantly greater than the controls for 17
and 6 days, respectively (P = 0.05), after treatment
application. Integrated over the 24-day-long study, microbial
respiration in ryegrass- and urea-amended soil increased 9.9 and 0.2 g
CO2 kg–1 soil over the controls, excluding CO2
production by carbonate hydrolysis. After ryegrass application, a
multi-component, time-response model fitted the data well including
rapid and, 2 days later, delayed, up-regulation responses of the
microbial community followed by a protracted asymptote.
Keywords nitrogen; ryegrass; soil respiration;
urea fertiliser application
A06050; Online publication date 3 July 2007; Received 9 September
2006; accepted 28 March 2007
New Zealand Journal of Agricultural Research, 2007, Vol. 50:
321–326
0028–8233/07/5003–0321 © The Royal Society of New Zealand 2007
PDF file of entire paper: Print-quality
(784K) | screen-quality (485K)
This year's abstracts |
Journal home page |
All abstracts |
Publishing home page
