A comparison of nutrient losses to waters following pasture
renewal by cultivation or direct-drilling
L.C. SMITH, R.W. McDOWELL and G.P. COSGROVE
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Agricultural soils enriched in phosphorus (P) have
been linked to increases in P losses and declining water
quality. Cultivation of pastures near sensitive waterways
lowers surface soil P and therefore the concentration of P
in surface runoff. However, such a practise can increase
the mineralisation of organic nitrogen (N), negating this
as a mitigation option for N sensitive catchments. A field
trial was set up to compare pasture renewal using either
direct-drilling or cultivation (which mixed the plough
layer to 150 mm) on hydraulically-isolated runoff plots
at Tussock Creek near Invercargill, Southland. The trial
ran from March to December 2015. Soil P concentrations
(0-150 mm depth) decreased in the cultivated plots by
about 20%, 8 months after cultivation. Concentrations of
nitrate-N in surface runoff and shallow drainage, and P in
shallow drainage only, were not different between directdrilling
and cultivation treatments. Cultivation reduced
filterable reactive P (FRP) losses in surface runoff by
69% (P=0.047) compared to direct-drilled plots. This
study showed that mixing P within the plough layer
decreased P loss over the 10 months of measurement.
Conventional tillage that inverts the plough layer may
result in even larger decreases in soil P concentrations.
Tillage can therefore be used as a strategy to decrease
P loss in small areas where surface runoff is likely, with
little risk of increasing catchment-scale N loss. This
includes near stream areas, but care must be taken to
leave an adequate buffer strip to prevent sediment (and
P) loss via erosion of bare soil.
Keywords: phosphorus-enriched soil, cultivation,
direct-drilling, runoff, drainage
A farmer’s view on the current environmental conversation
M.H. ADAMS
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The brief for this paper was: “A farmer’s view on
protecting the soil, water and environment.” However,
I have headed in a slightly different direction and would
like to focus on some of the tensions that exist within
this brief. To help me do this, I will tell my family
story starting with my grandfather James Adams. He
sold both his 100 ha farm and agricultural contracting
business in Duntroon, North Otago, to purchase an 890
ha farm in the Fairlie basin. In September 1950, at 42
years of age, my grandfather with his wife and eight
children made the move north. Over the next 33 years he
was able to acquire the neighbouring farms, effectively
doubling the land area before two of his sons joined
the business. Like many men from an era that included
two world wars and a severe depression, James was a
conservative man. He was prepared to borrow money to
buy land, but not to develop it. Development had to be
done out of income.
A protocol for sampling pastures in hill country
K.J. HUTCHINSON, D.R. SCOBIE, J. BEAUTRAIS, A.D. MACKAY,
G.M. RENNIE, R.A. MOSS and R.A. DYNES
view more
To develop a protocol to guide pasture sampling for
estimation of paddock pasture mass in hill country,
a range of pasture sampling strategies, including
random sampling, transects and stratification based
on slope and aspect, were evaluated using simulations
in a Geographical Information Systems computer
environment. The accuracy and efficiency of each
strategy was tested by sampling data obtained from
intensive field measurements across several farms,
regions and seasons. The number of measurements
required to obtain an accurate estimate was related
to the overall pasture mass and the topographic
complexity of a paddock, with more variable paddocks
requiring more samples. Random sampling from
average slopes provided the best balance between
simplicity and reliability. A draft protocol was
developed from the simulations, in the form of a
decision support tool, where visual determination of
the topographic complexity of the paddock, along with
the required accuracy, were used to guide the number
of measurements recommended. The protocol was field
tested and evaluated by groups of users for efficacy and
ease of use. This sampling protocol will offer farmers,
consultants and researchers an efficient, reliable and
simple way to determine pasture mass in New Zealand
hill country settings.
Keywords: hill country, feed budgeting, protocol
pasture mass, slope
An overview of the South Canterbury region
D.G. McFARLANE
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Welcome to South Canterbury – a region of diversity,
innovation and opportunity. I aim to provide you with
an overview of the region’s strengths and its potential
along with the challenges to be faced. This will not be
as a geographer - “Mr Google” could do that job better
than I; this will be my personal view as a practical
farmer who has been involved in a number of regional
developments.
Calculating “Hydrothermal time” to quantify seed germination of
tall fescue
S. SHARIFIAMINA, D.J. MOOT and M. BLOOMBERG
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The objective of this study was to quantify the combined
effects of temperature and moisture on germination of
tall fescue seed. Seeds were incubated for up to 50
days at a range of constant temperatures (5-35ºC) and
germinated at five water potentials (0, -0.18, -0.37,
-0.63 and -0.95 MPa). The maximum final germination
percentages were 94 to 98 at 15-30ºC when water
was not limited (0 MPa). Germination rate increased
linearly from 5 to 27.5ºC, and then decreased linearly
from 27.5 to 32.5ºC. Extrapolation of the sub-optimal
temperatures identified a base temperature of 3.5 ±
0.5ºC and an optimum temperature of 27.5ºC. More
negative water potential indicative of drier conditions,
delayed germination and reduced germination rate. The
average base water potential was -0.95 MPa at the suboptimal
range of temperatures. An optimum range of
germination (80-100%) occurred when temperatures
were between 10 and 30ºC and water potential was
between 0 to -0.37 MPa (moderate stress). These results
provide a matrix of soil temperature and moisture
conditions that are expected to result in successful
germination and therefore provide the maximum
opportunity for emergence of tall fescue seedlings.
Keywords: Festuca arundinacea, ‘Finesse Q’,
hydrothermal time
Clover root weevil tolerance of clover cultivars
C.M. FERGUSON, D.M. BARTON and B.A. PHILIP
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Clover root weevil arrived in New Zealand about
20 years ago causing major loss of productivity as
it progressively spread across the whole country. It
is now largely controlled by an introduced parasitic
wasp biocontrol agent Microctonus aethiopoides (Irish
ecotype). However, management of insect pests should
not rely on a single mechanism and clovers resistant or
tolerant to this weevil would be a useful augmentation
for farmers to have. This investigation reports on the
suitability of 22 clover cultivars to attack from the
weevil. Results have shown that contrary to popular
belief, red clovers are not universally less favourable to
the weevil than white clovers and usefully, within both
species cultivar differences point to the possibility of
resistance to this pest.
Keywords: Clover root weevil, Sitona obseletus,
clover cultivars
Conditions for co-existence of genetic modification in a pasture
based system – a farmer perspective
W.B.R. ROLLESTON
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Blue Cliffs Station in South Canterbury was taken
up by Henry Poingdestre in 1856, 5 years after my
great-grandfather, George Rhodes and his brother
Robert drove a flock of sheep from Banks Peninsula
to The Levels Station to establish the first run in
South Canterbury. It was from George that McKenzie
famously stole 1000 sheep in 1855 and was caught in
the now named Mackenzie Pass, only to escape again
into the mist the same night.
Dry matter yield, nutritive value and tiller density of tall fescue
and perennial ryegrass swards under grazing
S.J. HENDRIKS, D.J. DONAGHY, C. MATTHEW, M.R. BRETHERTON,
N.W. SNEDDON, G.P. COSGROVE, C.L. CHRISTENSEN, S. KAUFONONGA,
J. HOWES, M.A. OSBORNE, P.S. TAYLOR and M.J. HEDLEY
view more
Alternative pasture species with the potential to supply
quality forage during summer feed shortages, such as tall
fescue (TF), are of interest to dairy farmers. A paddockscale
study was undertaken to compare performance of
TF managed on a shorter rotation similar to perennial
ryegrass (RG) (TF-RG) with TF managed on a longer
rotation more consistent with its morphology of 4
live leaves/tiller (TF-TF), and with RG (RG-RG).
Accumulated dry matter (DM) yields were similar
for the three treatments. Patch grazing was observed
during the first spring, with more long patches in TFTF
than in either TF-RG or RG-RG. Sown-species leaf
area index (LAI) was greater in TF-TF compared with
TF-RG and RG-RG (2.25, 1.56 and 0.90, respectively;
P<0.05). The proportions of grass weeds were higher in
the TF-RG (P<0.05) compared with TF-TF and RG-RG
treatments (302, 207 and 164 g/kg DM, respectively).
A soil fertility gradient with distance along the paddock
away from the farm race was recorded, with Olsen P
declining at 0.130 mg/kg/m with distance from the farm
race. Tiller density, LAI and yield of sown species and
total yield sampled were all positively correlated with
Olsen P. Overall, this study highlights the importance of
managing TF pastures according to its specific growth
habits. However, attaining longer grazing rotations
under field conditions whilst trying to maintain cow
intakes, is likely to continue to prove elusive.
Keywords: perennial ryegrass (Lolium perenne), tall
fescue (Festuca arundinacea), grazing management
Earthworms stimulate pasture production in sheep and beef
systems: their economic value
N.L. SCHON, R.A. GRAY and A.D. MACKAY
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Earthworms have long been recognised to promote plant
growth but their contribution to pasture production in
managed pastures may be undervalued. At three field
sites pasture production was measured in an area where
surface active communities were found compared to a
more diverse area where the additional deep burrowing
earthworm Aporrectodea longa had been introduced.
Caution is needed when interpreting the results, as
all data are from paired areas and not replicates. The
influence of earthworms on pasture production was
positively correlated with the difference in abundance
of the topsoil species Aporrectodea caliginosa, with
this species being more abundant in the presence of
A. longa at two sites. Overall, the value of diverse
earthworm communities to pasture production was
estimated to be $365-$440/ha annually. In managed
pasture systems there is need to recognise the value of
maintaining and enhancing earthworm populations.
Keywords: pasture production, earthworm functional
diversity
Evaluation of perennial lupin/cocksfoot pasture relative to lucerne
pasture under summer dry conditions
A.D. BLACK and T.P. RYAN-SALTER
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The productivity of a perennial lupin/cocksfoot
mix was compared to that of lucerne in summer dry
conditions at Lincoln University, Canterbury, New
Zealand. The pastures were planted in December
2013 and rotationally grazed by ewe lambs in autumn
2014 (Year 1), and by ewe hoggets in spring-summer
and ewe lambs in autumn of 2014/2015 (Year 2) and
2015/2016 (Year 3). For lupin/cocksfoot relative to
lucerne in Years 1 to 3, sheep liveweight gains were
54% of 107 kg/ha, 68% of 1134 kg/ha and 50% of 1347
kg/ha; herbage dry matter yields were 122% of 3520
kg/ha, 64% of 10 230 kg/ha and 59% of 9680 kg/ha;
and in Years 2 and 3, the water use efficiency of sheep
liveweight gain was 76% of 2.0 kg/ha/mm and 49% of
2.7 kg/ha/mm, respectively. The lupin content in the
pre-grazing herbage in Years 1 to 3 averaged 42, 22
and 12%, whereas the lucerne content averaged 78, 95
and 98%, respectively. This showed that perennial lupin
was not persistent at this lowland site.
Keywords: Lupinus polyphyllus, Dactylis glomerata,
Medicago sativa, dryland, sheep liveweight gain, water
use
Genetic gain in perennial ryegrass forage yield in Australia and
New Zealand
M. HARMER, A.V. STEWART and D.R. WOODFIELD
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Genetic gain of forage yield in pasture species underpins
long-term productivity improvements in pastoral
agriculture. The value of proprietary seed sales in
Australia and New Zealand has resulted in more public
and private investment in perennial ryegrass breeding
than other forage species, but this is still much less
than for major row crops. Historic estimates of genetic
gain in total annual dry matter (DM) yield for perennial
ryegrass cultivars have ranged from 0.25 to 0.73% per
year, but ongoing questions from farmers and industrygood
organisations has prompted further assessment
of recent genetic gains. Analysis of 46 Australian and
New Zealand trials identified two distinct periods of
genetic gain: (a) before 1990, where genetic gain for
total annual DM yield was limited, and (b) after 1990
where consistent genetic gains of approximately 0.76%
per year or 105 kg DM/ha/year have occurred, with
rates higher than this especially in winter, summer
and autumn. Investigations to better understand the
key scientific and economic factors responsible for the
observed changes in rates of genetic gain are warranted,
as this may help inform policies and investment aimed
at further increasing rates of genetic gain in all forage
species.
Keywords: germplasm origin, endophyte, Lolium
perenne L., plant intellectual property rights, cultivar
evaluation
Gorse is a ‘facultative’ N2 fixer
W.Y.Y. LIU, M. PREMARATNE, R. CRESSWELL, D. DASH, D. JACK and M. ANDREWS
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Many legumes reduce their atmospheric N2 fixation per
unit biomass in response to increased soil N availability
but there are reports that some maintain a constant rate
of N2 fixation per unit biomass regardless of soil N
levels. These different responses to soil N availability
have been described, respectively, as ‘facultative’ and
‘obligate’ N2 fixation strategies. Views in the literature
differ if gorse is a facultative or obligate N2 fixer. Here,
firstly, the proportion of N derived from the atmosphere
(%Ndfa) was assessed for mature gorse plants mainly
in hedges bordering intensive agricultural land at
different sites in the Selwyn district, Canterbury, New
Zealand using the 15N natural abundance technique.
Secondly, the effect of nitrate (NO3
-) supply on %Ndfa
was determined for gorse seedlings under glasshouse
conditions using 15NO3
-. Under field conditions, values
ranged from 14.7-88.0 %Ndfa. In the glasshouse,
%Ndfa values decreased from 97 when no N was
supplied to 24 %Ndfa when N supply was increased to
the equivalent of 200 kg N/ha. It is concluded that gorse
shows a facultative N2 fixation strategy.
Keywords: legume, nitrate, 15N natural abundance,
nitrate reductase activity, gorse, Ulex europaeus
Impact of autumn (fall) dormancy rating on growth and
development of seedling lucerne
H.T. TA, E.I. TEIXEIRA and D.J. MOOT
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To quantify the influence of autumn (fall) dormancy
(FD) on DM production and phenological development
during the seedling phase, three lucerne genotypes with
contrasting ratings were grown at Lincoln University,
New Zealand. A dormant (FD2), a semi-dormant
(FD5), and a winter-active (FD10) genotype were
inoculated and sown at a rate of 290 plants/m2 on 8
October 2014. By the end of the seedling phase (15
January 2015) the FD10 genotype had produced 20%
higher shoot yield and 17% higher root yield than the
other two genotypes. The percentage of total biomass
partitioned to roots (Proot) was 50% for all genotypes.
Total plant biomass (root + shoot yields) was 6.55 t
DM/ha for FD10 compared with 5.57 t DM/ha for FD
2 and FD5. Plant height at the open-flower stage was
39.5 cm for FD10 compared with 34.5 cm for FD5 and
33.5 cm for FD2. Maximum leaf area index was similar
amongst genotypes at 2.5. However, individual leaf
area was 142, 119 and 111 cm2/stem for FD10, FD5
and FD2, respectively. The phyllochron was 52oCd per
primary leaf (base temperature of 1oC) and consistent
amongst genotypes. The number of primary leaves and
branches were also conservative at 17 and 14/shoot,
respectively. Therefore, differences in shoot yield
among these lucerne genotypes during the seedling
stage were mainly due to differences in plant height
and individual leaf area expansion per plant. This led
to greater light interception and therefore higher total
biomass accumulation for FD10 than for the other two
genotypes.
Keywords: alfalfa, autumn, Medicago sativa L.,
phyllochron
Innovative capital resources – South Canterbury
B.J.M. LOVE
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South Canterbury has a history of innovative capital
investment in agriculture, as a rural region of New
Zealand. Henry Sewell, an early Canterbury politician,
said in 1956 that “Timaru is a miserable apology for
a shipping place without wood or water. Nothing will
ever spring up there but a public-house, a store and a
woolshed”. Luckily, with innovative use of capital
resources that predication has been proven wrong.
Insect populations of six dryland pastures grown in Canterbury
N.J. MORRIS, M.C. SMITH, A.M. MILLS, M.R. McNEILL and D.J. MOOT
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The 9 year ‘MaxClover’ experiment at Lincoln
University concluded that ryegrass and white clover
pastures were less persistent than cocksfoot and lucerne
under dryland conditions in Canterbury. Measurements
of insect pests commenced in Year 5 in response to a
measured decline in sown ryegrass and white clover.
The aim was to determine if there were differences in
insect pressure among the different pastures. Insect
pest pressure was present in all pastures from when
measurements commenced until the experiment
finished in Year 9. Grass grub larvae were the main
pest that contributed to the decline in sown species,
particularly in ryegrass/white clover, and they were
found in all grass-based pasture treatments. Larval
populations reached 156/m2 in August 2008 in the
cocksfoot/balansa clover and cocksfoot/white clover
pastures. Argentine stem weevil overwintering adult
populations reached 63/m2 in July 2010 and were
highest in cocksfoot/Subterranean clover pastures.
These may have contributed to the slow decline in
cocksfoot. Low populations (<5/m2) of adult clover root
weevil were found in all treatments in winter 2010, with
dissection finding reproductively mature adults with no
indication of parasitism by Microctonus aethiopoides.
Lucerne was the only host of Sitona discoideus. Results
suggest insect pressure did not differ among the grassbased
pastures over the duration of measurements but
white clover appears to have been the main host for
grass grub.
Keywords: ‘MaxClover’, botanical composition,
Listronotus bonariensis (Kuschel), Sitona obsoletus,
Sitona discoideus, Costelytra zealandica, Aphodius
tasmaniae, Wiseana cervinata
Key pasture and milksolids production indicators from two Waikato
farmlets differing in inputs, stocking rate, pasture allowance and
nitrate leaching
C.G. ROACH, C.B. GLASSEY and K.A. MACDONALD
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Two DairyNZ farmlets, differing in nitrogen fertiliser
inputs, cow genetic merit and autumn/winter grazing
management, with stocking rates of 2.6 (‘Future’) and
3.2 (‘Current’) cows/ha, were compared for pasture
residual and quality over 4 years. Target intakes
for lactating cows were 18 and 16 kg DM/cow/day,
respectively, with target grazing residuals of 3.5-4 cm
(1500 kg DM/ha in late winter/spring, 7-8 clicks on
the rising plate meter) for both herds. Measurement
of grazing residuals, pasture quality and botanical
composition identified small differences between
farmlets. Grazing residuals on the Future farmlet
averaged 0.2 cm (0.4 clicks on rising plate meter, RPM)
(P<0.01) higher than on the Current farmlet with the
difference being 0.35 cm in late spring (P<0.01), 0.2
cm in summer (P<0.05), 0.3 cm in autumn (P<0.05) and
not significantly different in winter and early spring.
The metabolisable energy (ME) content of the pasture
on the Future farmlet was on average 0.2 MJ ME/kg
DM (P=0.06) lower than the Current farmlet over the
4 years (11.6 and 11.8 MJ ME/kg DM, respectively),
with the difference being significant (P<0.05) in early
spring. Despite lower annual pasture production,
pasture allowance per cow was higher on the Future
farmlet which resulted in higher pasture intakes
and milksolids production per cow, though lower
production per hectare. The results showed that grazing
residuals and pasture quality did not decline markedly
with increasing pasture allowance.
Keywords: pasture, grazing residual, pasture
allowance, pasture quality, milksolids
Levy oration – 2015
C.W. HOLMES
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New Zealand dairy farming has lost its competitive edge
Liveweight production of ewes and lambs grazing a dryland
lucerne monoculture with or without barley grain supplementation
D.J. MOOT, A.M. MILLS, M.M. ROUX and M.C. SMITH
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In 2013/2014 (Year 1) and 2014/2015 (Year 2) at Ashley
Dene, Canterbury, New Zealand, sheep grazing dryland
lucerne monocultures were supplemented with barley
grain. In neither year did barley grain supplementation
improve lamb growth rates. In 2013/2014 total
liveweight (LWt) production of lambs was 782 ± 11.5 kg
LWt/ha between 3/9/2014 and 3/2/2015 when pastures
were destocked. However, ewes with continuous access
to barley grain gained 12.4 kg LWt/ha over the lactation
period compared with those without access to grain that
lost 14.0 kg LWt/ha. In 2014/2015 (Year 2), liveweight
production of lambs totalled 408 ± 1.0 kg LWt/ha from
those with no access to grain and 382 ± 1.0 kg LWt/
ha from those with grain supplementation. Upon restocking
with weaned lambs, each lamb with access to
grain gained 154 ± 9.8 g/d which was less than those
without grain access (188 ± 9.7 g/d). Sheep ingested
25-83 g/d of grain with ad lib feeding. These results
support previous literature that suggests liveweight
responses from grain supplementation of sheep are
inconsistent.
Keywords: alfalfa, Medicago sativa, Hordeum vulgare,
feed conversion efficiency
Looking to the future of land evaluation and farm planning
E. J. DOMINATI, A.D. MACKAY, J.M. RENDEL and P. N. SMALE
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Land evaluation has a long
history of describing and
quantifying the sustainable
productive capacity of land.
There is a global recognition
of the need for this discipline
to start recognising the services
beyond food production
provided by landscapes, as well
as the impacts land uses have
on receiving environments.
An ecosystems approach was
used to extend land evaluation
to include additional outcomes
and was paired with farm
system optimisation to explore
farm system design. The
approach was tested on a sheep
and beef farm to explore the
added benefits of steep land
retirement for flood mitigation and soil conservation
and potential trade-offs with farm productivity. The
approach showed successfully that it is possible to aim
for multiple benefits ranging from increased profit to
decreased environmental footprints. Such capability to
define and include ecological boundaries within which
resources should be managed is a feature that analytical
farm system frameworks will require into the future.
Keywords: multi-functional land evaluation, ecosystem
services, farm system, optimisation
Measurement techniques and yield estimates of fodder beet in
Canterbury and Southland
H.G. JUDSON, S. McKENZIE, S. ROBINSON, A. NICHOLLS and A.J.E. MOORHEAD
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A survey of commercial fodder beet crops across
Canterbury and Southland was undertaken to determine
average yields and to provide some basic information
on commercial crops. Commercial yields were
approximately 19 t DM/ha but higher yields (34 t
DM/ha) were achievable. Dry matter content (DM%)
of bulbs was higher for lighter than for heavier bulbs.
Variation in DM% between bulbs was greater than
the variation between parts (inner and outer fractions)
of the bulb suggesting a rapid method of sampling
multiple bulbs may lead to increases in accuracy of
DM% assessment. A rapid coring method was tested.
Keywords: fodder beet, yield, survey, dry matter yield
Moving from exploring on-farm opportunities with a single to a
multi-year focus: Implications for decision making
J.M. RENDEL, A.D. MACKAY, P.N. SMALE and I.VOGELER
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In pastoral grazing farm systems there is growing
awareness of the importance of including year to
year variation in pasture grown when analysing and
designing appropriate and more profitable systems.
Few authors have clarified how an optimal farm system
incorporates inter-temporal variability. This paper
shows for a Whanganui hill country sheep and beef
farm, that inclusion of inter-annual variation in pasture
growth rate results in a more dynamic farm system
than when only average pasture production data are
used in a new, multi-year farm optimisation model.
The variation in stock numbers, sale dates and pasture
covers were quantified, as was the variation in farm
profitability (measured as Earnings Before Interest,
Tax, Depreciation and Amortisation, EBITDA).
Interestingly, there was only a small difference in Net
Present Value between the two approaches over 10
year’s simulation.
Keywords: farm systems, variability, INFORM, multiyear
National and regional maize grain and silage strip trial yields
N.J. MORRIS, T.D. HURLEY and R.J. DENSLEY
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Maize (Zea mays) grain yield in New Zealand has
increased linearly, on average by 104 kg/ha/year
(R2=0.51) while maize silage yield has increased linearly
on average by 166 kg DM/ha/year (R2=0.47), based on
strip trial data (1991-2015 for grain, and 1996-2015 for
silage). Over the same periods, grain yields (based on
14% moisture content) have increased on average in the
lower North Island (LNI) by 175 kg/ha/year (R2=0.45)
while average silage yields have increased in the
Waikato by 212 kg DM/ha/year (R2=0.48), in the LNI
by 177 kg DM/ha/year (R2=0.31) and the South Island
by 155 kg DM/ha/year (R2=0.30). Annual variations in
yield can be attributed to changes in trial locations and
trial co-operators over time. However, overall trends
towards increasing yield are due to improvements in
hybrid genetics, maize agronomy and management
practises. Growing and harvesting costs for producing
maize silage on an average soil fertility property in the
Waikato have increased 3 c/kg DM over 13 years.
Keywords: maize silage, maize grain, Zea mays, corn,
yield
NZGA PRESIDENT’S ADDRESS 2015
W. LISSAMAN
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Agricultural science, Government policy and the farmer
Optimal grazing management to achieve high yields and utilisation
of dryland lucerne
D.J. MOOT, S.M. BENNETT, A.M. MILLS and M.C. SMITH
view more
The pre- and post-grazing dry matter yields from
six individual paddocks in a grazed lucerne rotation
were compared at Ashley Dene, Lincoln University,
over 5 years. The mean annual yield was ~12 000 kg
DM/ha and unaffected by the rotation order in which
paddocks were first grazed in spring. On an annual
basis the post-graze residual was about 1000 kg
DM/ha lower from Paddock 1 than Paddock 6. First
grazing usually occurred with ewes and lambs in the
third week of September when the pre-grazing height
was 15-25 cm. Rapid spring growth of lucerne meant
Paddock 6 was sometimes over 40 cm tall with a pregrazing
mass of 4000 kg DM/ha upon first entry 4-5
weeks later. The grazing interval between the first and
second rotation in spring was between 29 and 36 days.
There was an average 1800 kg DM/ha more on offer
in Paddock 6 than Paddock 1 in the first rotation. On
average, the ewes and lambs consumed ~2100 kg DM/
ha at ~75% utilisation from each paddock in the first
rotation. Weaned lambs offered similar pre-grazing
yields consumed less herbage (~1700 kg DM/ha) at
~60% utilisation. A lower pre-graze target for lambs
(2000-2500 kg DM/ha) is therefore recommended,
particularly if there is no other class of stock available
to consume the residual. This may require a quicker
rotation with weaned lambs than the 34 days averaged
in this study. For ewes and lambs the target of ~3000
kg DM/ha (~30-35 cm pre-grazing height) used for this
study seemed appropriate rather than a fixed number of
days or particular phenological stage.
Keywords: alfalfa, lucerne, Medicago sativa L.,
rotational grazing, stock class, utilisation
Pasture renewal practices, experiences and attitudes:
a comparison over time
K. RIJSWIJK and R. BRAZENDALE
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In 2010, Waikato and Bay of Plenty dairy farmers
were surveyed by the Pasture Improvement Leadership
Group (PILG) to better understand their attitudes,
confidence and ability to make informed decisions
on their pasture renewal practices. To assess changes
in farmer behaviour towards pasture renewal and to
measure the impact of the PILG, the survey was repeated
in 2015. In comparison to 2010, the 2015 survey results
were more positive. Farmers’ confidence, attitude and
satisfaction with their ability to successfully renew
pasture, and to improve pasture performance have
increased. However, some scepticism remains about
time investment and the financial return from pasture
renewal. These results suggest that the PILG aim of
ensuring that consistent messages relating to pasture
renewal are provided to farmers, appears to have been
met. Farmers indicated in the 2015 survey that not only
is there now better information available in comparison
to 2010, the messages are also more consistent across
the industry.
Keywords: pasture renewal, pasture performance,
farmer confidence, farmer attitude, communication
Pathways ahead for New Zealand hill country farming
F.G. SCRIMGEOUR
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This paper provides a stocktake of the status of hill
country farming in New Zealand and addresses the
challenges which will determine its future state
and performance. It arises out of the Hill Country
Symposium, held in Rotorua, New Zealand, 12-13
April 2016. This paper surveys people, policy, business
and change, farming systems for hill country, soil
nutrients and the environment, plants for hill country,
animals, animal feeding and productivity, and strategies
for achieving sustainable outcomes in the hill country.
This paper concludes by identifying approaches to:
support current and future hill country farmers and
service providers, to effectively and efficiently deal
with change; link hill farming businesses to effective
value chains and new markets to achieve sufficient
and stable profitability; reward farmers for the careful
management of natural resources on their farm; ensure
that new technologies which improve the efficient use
of input resources are developed; and strategies to
achieve vibrant rural communities which strengthen hill
country farming businesses and their service providers.
Keywords: farming systems, hill country, people,
policy, productivity, profitability, sustainability
Premature mammary development in ewe lambs exposed to an
oestrogenic lucerne pasture
R.L. FIELDS, G.K. BARRELL and D.J. MOOT
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A report of mammary development in 6-month-old
ewe lambs grazing lucerne on a commercial farm in
North Otago provided an opportunity to investigate
the possibility to use this as a tool to detect oestrogenic
lucerne pastures. Of the 36 ewe lambs grazing lucerne
at this farm, protruding mammary glands were visible in
19. In contrast, none of the 22 ewe lambs grazing grass
had protruding mammary glands. The lucerne-fed ewe
lambs also had larger mean teat width than the grassfed
ewe lambs (17.9 ± 0.53 mm versus 13.4 ± 0.78 mm
respectively. The lucerne-fed animals were returned to
grass pasture 4 weeks before the introduction of rams.
There was no effect of the earlier 16 weeks of lucerne
grazing on the number of fetuses present in ewes near
mid-gestation compared with ewes on grass throughout
this period. These findings from a commercial farm
suggest that oestrogenic lucerne may be detected by
monitoring ewe lambs for mammary development. This
would enable farmers to manage pre-mating grazing of
ewes with minimal risk of lowered ovulation rates.
Keywords: sheep, coumestrol, oestrogen, fecundity,
Medicago sativa, alfalfa
Productivity and composition of perennial lupin pastures in
response to six sowing rates, lime application and lupin type at
Glenmore Station, Lake Tekapo
K.M. POLLOCK and D.J. MOOT
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This study aims to identify the sowing rate necessary to
produce lupin dominant and productive pastures in the
New Zealand high country under low-moderate fertility,
and a regime of late spring/early summer grazing. Blue
and Russell lupin were sown on 12 December 2012 at
rates of 2, 4, 8, 12, 16 and 32 kg/ha with cocksfoot at
2 kg/ha, and ± 3 t/ha lime. Low lupin sowing rates (<8
kg/ha) produced an open canopy with lupin density <4
plants/m2, suitable for cocksfoot but also prone to reinvasion
by resident species. The blue lupin population
was ~5 plants/m2 for sowing rates ≥8 kg/ha. The Russell
lupin population was <4 plants/m2 at sowing rates ≤16
kg/ha. Cocksfoot population was 1.3 and 1.9 plants/m2
with blue and Russell lupin, respectively. Dry matter
(DM) yield (excluding dead material) was 4.9 t/ha for
spring 2014 and 2.1 t/ha for spring 2015, a difference
attributed to the low spring rainfall in 2015. Blue lupin
contributed more to the total DM yield than did Russell
lupin as sowing rates increased. Cocksfoot dominated
the remainder of production in spring 2014 but was on
a par with resident species production in spring 2015.
Summer and autumn regrowth to March 2015 was
limited to ~1 kg DM/ha. There was no appreciable
regrowth during December 2015 - March 2016. A
lupin sowing rate of 8 kg/ha was adequate. Blue lupin
population was greater than Russell lupin.
Keywords: Lupinus perennis L. polyphyllus, plant
density
Relationships between dry matter yield and height of rotationally
grazed dryland lucerne
A.M. MILLS, M.C. SMITH and D.J. MOOT
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Between 2009/2010 and 2014/2015 a total of 711
destructive paired samples of total dry matter yield (kg
DM/ha) and lucerne height were taken from a grazed
dryland lucerne monoculture experiment at Ashley
Dene, Canterbury, New Zealand. These were used to
develop relationships suitable for on-farm estimates of
lucerne. For pre-graze yields, the variation accounted
for increased from 59%, based on lucerne height alone,
to 84% for the 14 Year/Season combinations. For postgrazing
residual DM yields, inclusion of Year as a factor
increased the R2 from 0.39 to 0.65. Pre-graze data were
also grouped into spring, summer and autumn. These
relationships accounted for 54-60% of the observed
variation in dryland lucerne. In spring the multiplier
was ~95 kg DM/cm and this dropped to ~75 kg DM/
cm for heights measured in the summer. In autumn the
multiplier was ~55 kg DM/cm. Lack of stability in the
relationships over time could reflect environmental
conditions and changes in stand density which height
measurements alone cannot account for.
Keywords: alfalfa, dry matter yield estimates, height,
Medicago sativa L., regression analysis
Response to clover root weevil outbreaks in South Canterbury,
Otago and Southland; the agricultural sector and government
working together
S. HARDWICK, C.M. FERGUSON, P. McCAULEY, W. NICHOL, R. KYTE,
D.M. BARTON, M.R. McNEILL, B.A. PHILIP and C.B. PHILLIPS
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Clover root weevil was first discovered in the northern
South Island in 2006, and an introduced biocontrol
agent the parasitoid wasp Microctonus aethiopoides,
was immediately released there in response. As the
weevil spread southwards, ongoing releases and
natural parasitoid dispersal generally supressed it to
economically tolerable levels. However, mild winters
in the southern South Island during 2013 and 2014
allowed weevil populations to grow and spread quicker
than the parasitoid. This severely impacted white clover
production and farm profitability in parts of South
Canterbury, Otago and Southland, thus, scientists and
industry conducted 18 months of intensive parasitoid
releases of ca. 1.1 million parasitised weevils at 6000
sites. The parasitoid rapidly established at all 50
monitored release sites and dispersed from them. The
biocontrol agent now occurs at all locations in South
Canterbury, Otago, Southland, and elsewhere in New
Zealand, where clover root weevil is present.
Keywords: biological control, pest spread, parasitic
wasp, Sitona obsoletus, Microctonus aethiopoides,
South Canterbury, Southland, Otago
Towards the integrated assessment of New Zealand pastoral farm
systems
M.B. DODD and D.R. STEVENS
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Land use and management change is a feature of New
Zealand farm systems, driven by a range of factors
including volatile markets and exchange rates, variable
weather and climate patterns, continuous policy
evolution and the inherent innovation of New Zealand
farmers. Yet the common indicators used to evaluate
the impact of change appear to be limited to the link
between productivity (of land/labour/capital) and
profitability. However, if farm system “owners” seek
truly sustainable systems they should consider a wider
set of indicators to guide investment. Sustainability is
considered in terms of the ability of the pastoral farm
system to fulfil its primary purpose in the long-term,
i.e. “to derive value from the natural capital of a land
and water resource that is sufficient to support the
objectives of the resource owner” and fulfil secondary
objectives considered important by other stakeholders
(e.g., product and environmental quality). The objective
of this study was to develop an integrated assessment
framework for sustainability indicators that was useful
for guiding change decisions at the farm system scale,
a key determinant of regional economic, environmental
and social outcomes. The approach is based on the
fundamental properties of a complex adaptive system:
existence, effectiveness, freedom of action, security,
adaptability and coexistence, applied to six key system
drivers (financial, environmental, social, cultural,
technological and regulatory). This framework could
support decision-making in terms of the investment
of human, natural and financial capital at the farm
system scale and contribute to larger scale information
imperatives (e.g., value chains, catchments).
Keywords: integrated assessment, pastoral farm
systems, sustainability, systems properties
Urinary nitrogen concentration from dairy heifers grazing kale
supplemented with either plantain or perennial ryegrass baleage
in winter
H.G. JUDSON and G.R. EDWARDS
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The effect of feeding two different supplements
(perennial ryegrass or plantain baleage) on urinary
nitrogen (N) excretion from dairy heifers (8 months old,
180 kg liveweight (LW)) grazing kale was examined in
two successive winters. Heifers (n=90 and 80 in Years
1 and 2, respectively) were offered 2.5 kg DM kale/100
kg LW/day and approximately 3 kg DM/heifer/day of
either perennial ryegrass or plantain baleage. Urine
samples were collected 2-4 times throughout winter,
acidified and frozen before N analysis. Despite similar
apparent N-intake, urinary N concentration from
heifers supplemented with plantain baleage (0.36%
N) was lower (P<0.05) than those supplemented with
perennial ryegrass baleage (0.53% N). Creatinine
concentrations in urine and observations of urination
frequency suggest some of the decrease in urinary-N
concentration may be due to increases in urine volume
when heifers were fed plantain baleage. Liveweight
gain (g/heifer/day) was similar (P>0.05) for heifers
fed either supplement. The results indicate that feeding
plantain baleage to dairy heifers grazing kale in winter
may be a useful approach to decrease the N loading
in urine patches with subsequent reductions in nitrate
leaching.
Keywords: dairy heifer, kale, plantain, urinary nitrogen
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