New Zealand Journal of Agricultural Research abstracts
Agronomical and physiological responses of white clover (Trifolium
repens) and perennial ryegrass (Lolium perenne) to nitrogen fertiliser
applied in autumn and winter
M. L. Castle*
J. S. Rowarth†
I. S. Cornforth†
Soil, Plant and Ecological Sciences Division
P.O. Box 84
Lincoln University
Canterbury, New Zealand
email: maria.castle@agresearch.co.nz
*Present address: Plant Breeding and Genomics, AgResearch, Private Bag
3123, Hamilton, New Zealand.
† Present address: UNITEC, Private Bag 92 025, Auckland, New Zealand.
J. R. Sedcole
Applied Management and Computing Division
P.O. Box 84
Lincoln University
Canterbury, New Zealand
Abstract Mixed pastures of white clover and ryegrass
are profitable and widely used. However, loss of clover is common with time
due to N fertiliser applications in late winter. The factors that cause this
loss have yet to be determined. This work investigated reasons for the competitive
disadvantage suffered by white clover relative to ryegrass in autumn and
winter. White clover (Trifolium repens cv. ‘Grasslands Huia’) and
ryegrass (Lolium perenne cv. ‘Grasslands Nui’) were sown in March
in Canterbury, New Zealand, and grown as single plants in silica sand. Nitrogen
(N; 0.5 mol m-3 N); was applied daily simulating an unfertilised
soil; solution N concentration was increased to 5.0 mol m-3 N
for treatments in autumn (May) or winter (August), simulating fertiliser
treatment. Net photosynthesis was measured before each harvest and over a
diurnal period at 123 days after sowing. Plants were destructively harvested
six times (33-185 days after sowing) and plant dry weight and N concentration
(%) measured. White clover had a significantly (P < 0.05) lower dry weight
than ryegrass. Extra N applied from May significantly increased (P < 0.05)
dry weight of ryegrass. No significant changes in shoot N concentration were
found. Except at the last harvest, net photosynthesis was significantly lower
(P < 0.05) in white clover than in ryegrass; this was also apparent for
diurnal net photosynthetic rates 123 days after sowing. Results indicated
that white clover growth was limited by temperature, whereas ryegrass growth
was limited by N supply.
Keywords apparent nitrogenase activity; Lolium perenne;
nitrate; nitrogen fertiliser; perennial ryegrass; photosynthesis; Trifolium
repens; white clover
A01030 Received 2 October 2001; accepted 21 August 2002; published 9 December
2002
New Zealand Journal of Agricultural Research, 2002, Vol. 45: 283-293
0028-8233/02/4504-0283 $7.00/0 © The Royal Society of New Zealand
2002
PDF file of entire paper: Print-quality (295K) |
screen-quality (105K)
This year's abstracts |
Journal home page |
All abstracts |
Publishing home page
