New Zealand Journal of Agricultural Research abstracts
Base temperature and thermal time requirements for germination and emergence of
temperate pasture species
D. J. MOOT
W. R. SCOTT
A. M. ROY
A. C. NICHOLLS
Field Service Centre
P.O. Box 84
Lincoln University
Canterbury, New Zealand
Abstract The base temperature (Tb) and thermal time (Tt)
requirements for germination and emergence of temperate herbage species were
defined using a linear model of development rate against temperature. A Tb of
<= 4deg.C was found for all species. The Tt requirement for germination was
lower for legume than grass species and generally lowest for small seeded
species. The poor relationship (R2 = 0.42) between Tt
requirements for germination and 50% field emergence indicated that germination
results could not be extrapolated to predict the rate of field emergence. The
Tt for 50% field emergence was highest for the small-seeded grass species
cocksfoot (220deg.Cd) and timothy (200deg.Cd). The times (days and Tt) for
emergence of white clover and perennial ryegrass were similar from five autumn
sowing dates but 57 days after sowing on 21 March 1996 ryegrass seedlings were
12 times heavier. The implication of these results for establishment of pasture
mixtures is discussed together with the need for accurate measurement of soil
temperatures to assist the prediction of field emergence.
Keywords base temperatures; chicory; cocksfoot; emergence;
germination; Italian ryegrass; lucerne; pasture establishment; perennial
ryegrass; phalaris; prairie grass; red clover; subterranean clover; tall
fescue; temperatures; thermal time; timothy; white clover
New Zealand Journal of Agricultural Research, 2000, Vol. 43: 15-25
0028-8233/00/4301-0015 $7.00/0 (c) The Royal Society of New Zealand
2000
PDF file of entire paper: medium quality (780K); (scanned from paper original: notes about this process)
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