New Zealand Journal of Agricultural Research abstracts
Effect of lime and form of superphosphate on productivity of
dryland pastures
J. D. MORTON
New Zealand Pastoral Agriculture
Research Institute
Invermay Research Centre
Private Bag 50034
Mosgiel, New Zealand
D. M. WHEELER
New Zealand Pastoral Agriculture
Research Institute
Ruakura Research Centre
Private Bag 3123
Hamilton, New Zealand
N. S. SMITH
New Zealand Pastoral Agriculture
Research Institute
Poukawa Research Centre
P. O. Box 8144
Havelock North, New Zealand
Abstract The effect of initial high lime (7500 kg
ha-1), annual low lime (200 kg ha-1 yr-1), and
no lime (all with 200 kg ha-1 yr-1 superphosphate) and
dicalcic superphosphate (400 kg ha-1 yr-1) was compared
over six years under sheep grazing and mowing on a low rainfall (800 mm), low
pH (5.4), phosphorus (P) responsive (Olsen P 5) Matapiro yellow-grey earth
(Duric palic) soil near Hastings, Hawke's Bay, New Zealand. High lime
significantly increased pasture dry matter yield compared with other treatments
in the first three years of the trial under both grazing and mowing. There were
no differences in annual yield between the other treatments. The response to
high lime in relation to no lime in the first 3 years was greater under grazing
(21%) than mowing (12%). There was a greater number of legume plants per
m2 under mowing than grazing. The increase in pasture yield from
high lime in the grazing trial was because of an increase in grass rather than
legume yield. Legume yield averaged over all years was similar for the other
treatments. There was no significant difference in the P concentration of
grasses between treatments. Compared with low lime, high lime resulted in an
initial increase of 0.9 pH units. Low lime and dicalcic superphosphate
maintained the initial soil pH. The initial low Olsen P levels were only
slightly increased by the low rates of P fertiliser used.
After six years, P applications ceased on the dicalcic and low lime
treatments, and the high lime plots were split into no P and P (20 kg
ha-1 yr-1) applied. During the residual effect phase
(Year 7-17), there was no difference in annual yield between no lime and high
lime when P applications continued. For all treatments, where P was withheld,
annual yield was lower than where P was maintained.
Application of high initial rates of lime in this environment resulted in a
short-lived (3 year) response in pasture yield despite a large increase in soil
pH. At equivalent rates of P there was no difference in the effectiveness of
single and dicalcic superphosphate. The liming effect of dicalcic was matched
by applying the equivalent low rate of lime as a dry mix in addition to
superphosphate.
Keywords dicalcic; superphosphate; lime; pasture production;
legume; soil pH; Olsen P; grazing; mowing
New Zealand Journal of Agricultural Research, 1998, Vol. 41: 65-74
0028-8233/98/4101-0065 $7.00/0 (c) The Royal Society of New Zealand
1998
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