Adaptation of Trifolium repens × T. uniflorum hybrid clovers to
drought stress
KEITH WIDDUP, SHIRLEY NICHOLS, WARREN WILLIAMS, ISABELLE VERRY and BEN HARVEY
view more
Abstract
White clover (Trifolium repens L.) is valued for its
contribution to pasture quality and utilisation by
animals, compatibility with grass, and fixation of
nitrogen. However, it is limited by poor adaptation to
drought. Hybridisation with Trifolium uniflorum L.
may have potential to improve the drought resistance
of white clover. An experiment in a rain shelter facility
with contrasting moisture treatments, and a field
evaluation under dryland conditions, were used to
compare the agronomic potential of these interspecific
hybrids (ISH) with white clover in moisture limited
conditions. In the rain shelter experiment, there were
smaller effects of water stress on shoot dry weight
(DW), leaf area, internode length and senescence of
first backcross generation hybrids compared with
white clover and second backcross generation hybrids.
Differences in photosynthetic responses were possibly
influenced by the effect of root DW allocation on water
uptake. In the field evaluation, growth scores of a wider
range of hybrid families during summer moisture stress
concurred with the results under water stress in the rain
shelter. Growth of some ISH families outperformed
the best white clover cultivars, particularly in the
third and most stressful summer and this result was a
key performance indicator of the value of the hybrids
for drought prone areas. These findings using early,
unselected, hybrid populations indicate the potential
for further selection of elite, adapted cultivars from ISH
breeding strategies.
Keywords: Interspecific clover hybrid, drought
resistance, rain shelter, field evaluation
Agronomic assessment of gibberellic acid and cytokinin plant
growth regulators with nitrogen fertiliser application for increasing
dry matter production and reducing the environmental footprint
A. GHANI, S. LEDGARD, J. WYATT, W. CATTO
view more
Abstract
Plant growth regulators (PGRs) are increasingly being
used in agriculture for a variety of purposes. In pasture
systems, the use of PGRs is relatively new and the effects
of its application on plant productivity and physiology
are poorly understood. A mowing trial was established
in Waikato in early spring 2012. Key objectives from
this study were: to determine effects of gibberellic
acid (GA3) and cytokinin (CPPU) application with and
without nitrogen (N) fertiliser application on pasture
production, N concentration (%N), root biomass and
potential reduction in N leaching from grazed pastures.
Treatments (with five replicates) were: control, urea
(40 kg N/ha), GA3 at two rates +/- urea, and CPPU at
three rates +/- urea. Implications for grazed pasture
and N leaching were modelled for a case study dairy
farm. Application of GA3 alone showed a significant
(P<0.05) rapid increase in dry matter (DM) production
compared with the control between 5 and 29 days
after application. The DM yields from GA3 alone were
similar to those with urea-N alone and the effects of
applying GA3 and urea-N together were additive.
Application of CPPU showed no significant effect on
pasture production. There were no treatment effects
from either PGR on root biomass. The %N in herbage
was significantly lower in the GA3 treated plots than the
control, which would reduce urinary-N excretion under
grazing. Preliminary modelling of data for a grazed
pasture showed a potential reduction in annual urine-N
leaching of 4–29%.
Keywords: Gibberellic acid (GA3), cytokinin (CPPU),
dry matter yield, total N, root biomass
An evaluation of lucerne for persistence under grazing in
New Zealand
B.M. HARVEY, K.H. WIDDUP and B.A. BARRETT
view more
Abstract
The on-farm use of lucerne (Medicago sativa) for
grazing and conserved feed has increased in New
Zealand over recent years, with new cultivars coming
onto the market, including more winter-active ones.
The extent to which the winter active types contribute to
annual feed production, and the relationship to critical
traits like persistence, has not been systematically
tested. Two concurrent trials over a 4-year period were
used to evaluate a range of lucerne cultivars and elite
experimental populations ranging in dormancy from 2
(highly dormant) to 10 (non-dormant) under contrasting
grazing regimes near Lincoln, New Zealand. More
winter-active cultivars in the higher fall dormancy
(FD) classes had similar growth to lower FD classes in
all seasons except autumn, where they exhibited 18%
greater yield than the lowest FD entry. However, these
higher FD populations do not persist as well under
heavy grazing, with a reduction in ground cover of up
to 90% after four years, compared with only a 25% loss
in lower FD classes. There was a negative correlation
between FD and persistence measured as plant survival
over 4 years (R2=0.73). However, one high FD entry
showed increased survival under grazing, suggesting
there is scope for selection of types with improved cool
season growth and grazing tolerance. The concurrent
lucerne trial subjected to a low-frequency grazing/
cutting regime showed faster recovery from defoliation
than the adjacent hard grazed regime, suggesting
stored underground reserves were more available for
regrowth. We concluded that lucerne cultivars with FD
ratings in the 3 to 5 range are most suitable for yield and
persistence under grazing in these conditions. There is
also scope for breeding to improve plant survival and
dry matter yield within FD class.
Keywords: Lucerne (Medicago sativa), grazing
tolerance, persistence, fall dormancy
Caucasian clover responses to fertiliser, lime and rhizobia
inoculation at Lake Heron Station, Canterbury
A.D. BLACK, A.J. HARVEY, J.L. MOIR and D.J. MOOT
view more
Abstract
The agronomic performance of Caucasian clover
in high country grasslands was the subject of two
experiments at Lake Heron Station, Canterbury. In the
first experiment, Caucasian clover was direct drilled into
an undeveloped pasture (soil pH = 5.5; Olsen P = 7 mg/
litre) with fertilisers containing similar P and S but ± 20
kg/ha of N, in December 2011. After 11 months, shoots
of Caucasian clover were small (3 mg), indicating an
inoculation failure, and effects of fertilisers were not
biologically meaningful. Therefore, the influence of
rhizobia inoculant, superphosphate and lime on early
growth of Caucasian clover was assessed using the
same soil in a glasshouse. Un-inoculated plants were
13–24% the size of inoculated plants and this lack of
vigour was not overcome by fertilisers. In the second
field experiment, an established Caucasian clover/
browntop pasture (soil pH = 5.5; Olsen P = 5 mg/litre)
received 0, 100, 200 and 400 kg/ha of superphosphate
with 0 or 5 t/ha of lime in February 2012. Despite the
high inputs, spring pasture yields 9 and 21 months after
fertiliser application were low (1260–2400 kg DM/
ha), but the contribution of Caucasian clover was high
(66–76%).
Keywords: high country, nitrogen, phosphorus,
Trifolium ambiguum
Central Otago – Built on gold, growing on grass.
BARRIE J WILLS
view more
A warm welcome to our “World of Difference” to all
delegates attending this conference – we hope your stay
is enjoyable and that you will leave Central Otago with
an enhanced appreciation of the diversity of land use
and the resilient and growing economic potential that
this region has to offer.
Without regional wellbeing the national economy
will struggle to grow, something Central Government
finally seems to be realising, and the Central Otago
District Council Long Term Plan 2012–2022 (LTP)
signals the importance of establishing a productive
economy for the local community which will aid in
the economic growth of the district and seeks to create
a thriving economy that will be attractive to business
and residents alike. Two key principles that underpin
the LTP are sustainability and affordability, with the
definition of sustainability being “… development that
meets the needs of the present without compromising
the ability of future generations to meet their own
needs.”
Challenges facing the farmers of Central Otago
D.R. STEVENS and J.P. GARDEN
view more
The Central Otago region, with its cold winters and
hot summers, and valley floors with uplift mountains
is definitely “a world of difference”. At the NZGA
conference in Alexandra in 1966 John Hercus stated
“Central Otago has a lure which sets it apart from the
rest of New Zealand. Its characteristics of geology,
topography and climate, its history of occupation and
exploitation, its scenery at once forbidding and yet
strangely fascinating – these features combine to cast a
spell which few who have been exposed, can ever fully
escape” (Hercus 1966). The region and its high country
have an iconic status epitomised by the “Southern Man”
stereotype. This places Central Otago deep in the psyche
of the nation. With this goes a unique and significant set
of conditions under which farming must take place. Not
only does the region have the biophysical challenges of
soils, water and climate to contend with, but a wider set
of values, often imposed from elsewhere.
Fifty years after that first conference we remain
challenged. What are the opportunities in front of us
and how should we best accommodate the challenge of
maintaining a viable enterprise and at the same time,
respecting the intense public and customer interest in
our use of land and livestock?
Central Otago and the associated high country of the
Lakes district and McKenzie basin can be divided into
three farming types. These are the valley floor irrigable
type, the flat and downland dryland regions, and the
high country. Each of these has challenges that are at
times unique, but often overlap with problems faced in
other regions.
Deriving pasture growth patterns for Land Use Capability Classes
in different regions of New Zealand
R. CICHOTA, I. VOGELER, F.Y. LI and J. BEAUTRAIS
view more
Abstract
Farm system models are increasingly being used to
assess the implications of land use and practice changes
on profitability and environmental impacts. Exploring
implications beyond individual farms requires the
linkage of such models to land resource information,
which for pastoral systems includes forage supply.
The New Zealand Land Resource Inventory (LRI)
and associated Land Use Capability (LUC) database
includes estimates of the potential stock carrying
capacity across the country, which can be used to derive
annual, but not seasonal, patterns of pasture growth.
The Agricultural Production Systems Simulator
(APSIM) was used, with generic soil profiles based on
descriptions of LUC classes, to generate pasture growth
curves (PGCs) in three regions of the country. The
simulated pasture yields were similar to the estimates
in the LRI spatial database, and varied with LUC Class
within and across regions. The simulated PGCs also
agreed well with measured data. The approach can be
used to obtain spatially discrete estimates of seasonal
pasture growth patterns across New Zealand, enabling
investigation of land use and management changes at
regional scales.
Key words: APSIM modelling, pasture growth curve
(PGC), year to year variability, farm system analysis
Dry matter intake and body condition score change of dairy cows
grazing fodder beet, kale and kale-oat forage systems in winter
G.R. EDWARDS, J. M. de RUITER, D. E. DALLEY, J.B. PINXTERHUIS, K.C. CAMERON,
R.H. BRYANT, H.J. DI; B.J. MALCOLM and D.F CHAPMAN
view more
Abstract
Crop dry matter (DM) yield, DM utilisation and body
condition score (BCS) of dairy cows were measured
over two winters on an irrigated stony, free-draining
Balmoral soil for three crop grazing systems: fodder
beet (FB); early-sown kale (EK); and late-sown kale
with oats grown in sequence (LK). There were two
replicates of each treatment, with 35–58 cows per
treatment group. Allocations of crop and supplements
(kg DM/cow/day) were: FB, 8 kg fodder beet + 6 kg
grass baleage; EK, 14 kg kale + 3 kg barley straw; LK,
11 kg kale + 5 kg green chop oat baleage. Pre-grazing
crop DM yield (t DM/ha) was higher in FB (20.1) than
EK (14.6) and LK (12.9). DM utilisation was high in all
treatments averaging 99.6%, 90.5% and 87.1% for FB,
EK and LK, respectively. Body condition score change
over the 8-week winter-feeding period was similar
for cows offered FB (+0.76), EK (+0.66) and LK
(+0.76). Allocation of feed quantity is more important
in determining BCS gain than the type of crop and
supplement fed.
Keywords: Brassica oleracea L., Beta vulgaris L.,
metabolisable energy
Early performance of oversown pasture mixtures on non-cultivable
hill country at four geo-climatically different sites
K.N. TOZER, G.B. DOUGLAS, R.A. MOSS, G.M. RENNIE, T.L. KNIGHT, T.J. FRASER,
C.A. CAMERON and P.D. MUIR
view more
Abstract
A trial was conducted on non-cultivable hill country
(>20o slope) at four sites to determine the effect of seed
mixture (grass+legume+herb vs legume) and sowing
time (spring vs autumn) on plant establishment. Sites
were in Canterbury (1 site), Hawke’s Bay (2) and
Waikato (1) on north and south aspects and differed
predominantly in climate. In the first spring after
sowing (12 months after spring sowing; 6 months
after autumn sowing), sown legume and total sown
species contributions (% of total dry matter (DM))
were: greater in the grass+legume+herb than legume
mixtures; greater when sown in spring than autumn (15
vs 7% for sown legumes and 41 vs 21% for total sown
species); and similar on north and south aspects. Sown
grass contribution was greater from autumn than spring
sowing (79 vs 65%) while sown herb contribution was
greater from spring than autumn sowing (15 vs 1%),
but both were similar across aspects. The contribution
of unsown species was high, averaging 59% in springsown
swards and 78% in autumn-sown swards. There
was no effect of seed mixture or sowing time on DM
production in spring (September–November; averaging
2660 kg DM/ha in Canterbury and 5080 kg DM/ha
at a Hawke’s Bay summer-moist site). However, DM
production was greater in spring- than autumn-sown
swards in summer at both sites (December–February;
Canterbury: 1980 vs 1520 kg DM/ha; Hawke’s Bay:
3980 vs 2670 kg DM/ha). In a wet year, broadcasting
seed during spring rather than autumn is likely to result
in the highest early DM production and contribution
of sown species (sown grasses, legumes and herbs)
in the sward. The high unsown species contribution
emphasises the importance of dealing with the seed
bank before establishment, especially when sowing in
autumn.
Keywords: seed mixture; pasture establishment;
botanical composition; unsown species ingress; pasture
improvement.
Effect of timing of harvest on nutritive value of four cultivars of
kale (Brassica oleracea L. var. acephala)
C.T. WESTWOOD, M.K. CUTTS, R.J. RUSSELL and K.M. O’BRIEN
view more
Abstract
A single site, single year replicated study in Canterbury
investigated change in nutritive value and dry matter
(DM) yield of four kale cultivars harvested monthly
between May and September.
The proportion of leaf relative to stem was
significantly higher for an intermediate kale (‘Regal’)
and short marrow-stem kale (‘Kestrel’) compared with
two giant kales ‘Gruner’ and ‘Rawera’. Late winter loss
of leaf was greater for ‘Gruner’ and ‘Rawera’ compared
with ‘Regal’ or ‘Kestrel’. Whole plant DM% remained
stable through winter (average 11.9%). Lower stem
contained more DM than top stem or leaf. The DM% of
‘Gruner’ was significantly higher than other cultivars.
‘Kestrel’ contained significantly more megajoules of
metabolisable energy than other kales. Energy content
of leaf and top sections of stem averaged 2.5 MJME/kg
DM more than lower stem.
Dry matter yield peaked in June then declined monthly
thereafter for giant kales ‘Gruner’ and ‘Rawera’, but
not ‘Regal’ or ‘Kestrel’. The use of intermediate and
short marrow-stem kales ‘Regal’ and ‘Kestrel’ is one
management option to improve the leafiness and whole
plant energy content of late winter feed crops.
Keywords: Forage brassica, kale, nutritive value,
winter feed, yield
Effects of fertiliser nitrogen management on nitrate leaching risk
from grazed dairy pasture
IRIS VOGELER1, MARK SHEPHERD2 and GINA LUCCI2
view more
Abstract
Dairy farms are under pressure to increase productivity
while reducing environmental impacts. Effective
fertiliser management practices are critical to achieve
this. We investigated the effects of N fertiliser
management on pasture production and modelled
N losses, either via direct leaching of fertiliser N, or
indirectly through N uptake and subsequent excretion
via dairy cow grazing. The Agricultural Production
Systems Simulator (APSIM) was first tested with
experimental data from fertiliser response experiments
conducted on a well-drained soil in the Waikato region
of New Zealand. The model was then used in a 20-
year simulation to investigate the effect of fertiliser
management on pasture response and the impacts on
potential leaching losses. The risk of direct leaching
from applied fertiliser was generally low, but at an
annual rate of 220 kg N/ha exceeded that from urine
patches in one out of 10 years. The main effect of N
fertiliser on leaching risk was indirect via the urine
patch by providing higher pasture yields and N
concentrations.
Best management practices could include
identification of high risk periods based on
environmental conditions (e.g. soil moisture, plant
growth), avoidance of fertiliser applications in these
periods and the use of duration controlled grazing
(DCG) to prevent excreta deposition onto the grazing
area during critical times.
Keywords: Modelling, APSIM, N fertilisation rates, N
fertilisation timing, direct and indirect leaching, urine
patches
Elevated atmospheric CO2 alters heading date of perennial ryegrass
B.R. MAW, C.S. JONES, P.C.D. NEWTON and J.-H.B. HATIER
view more
Abstract
Carbon dioxide (CO2) levels are increasing globally
and affect plant growth and development. Time to
flowering, commonly referred to as heading date, has
been identified as a key indicator of the quality and
nutritional value of ryegrass. Recent research on annual
grasses indicates that elevated CO2 levels can delay
heading date, however significant data for perennial
ryegrass is lacking. We exposed currently available
ryegrass cultivars to the CO2 concentration expected in
2050 (500 ppm) and found significant changes in heading
date with delays and advances of up to 10 days. Over
all the cultivars the breadth of heading date was more
than doubled, offering potentially new possibilities for
cultivar choice for specific environments and systems.
Keywords: Lolium perenne, climate change, plant
phenology, phosphorus, nitrogen
Identification and effectiveness of rhizobial strains that nodulate
Lupinus polyphyllus
T.P. RYAN-SALTER, A.D. BLACK, M. ANDREWS and D.J. MOOT
view more
Abstract
Lupinus polyphyllus plants were heavily nodulated at 10
field sites sampled across the South Island. Twenty-two
bacterial isolates from these nodules formed functional
nodules on L. polyphyllus indicating that rhizobia that
nodulate L. polyphyllus were present across a wide
range of sites in the South Island. Gene sequences
identified all 22 isolates and the Group G commercial
inoculant as Bradyrhizobium. Eleven isolates and the
Group G inoculant were tested for their effectiveness
on growth of L. polyphyllus plants in a high country
soil in a glasshouse. All plants nodulated regardless
of inoculum treatment but there was variability in
effectiveness. This suggests that it may be beneficial
to use a rhizobial inoculant for high country soils, but
further work is required before a recommendation can
be made.
Keywords: nitrogen fixation, perennial lupin, Lupinus
polyphyllus
Improving summer and autumn feed quality in New Zealand hill
country
G.M. RENNIE, W.McG. KING, T.L. KNIGHT, B. DEVANTIER and C.J.HOOGENDOORN
view more
Abstract
Management of late spring surpluses to restrict
reproductive growth can increase the quality of hillcountry
pastures during summer and autumn. This
occurs through a reduction in accumulated stem
and dead material and an increase in clover content.
However, there is little information on the magnitude
and longevity of these effects. This trial investigated
the effects of four late spring defoliation intensities on
herbage quality, measured at the end of spring and during
summer. Treatments were applied through regular
cutting of hill pastures in areas of medium fertility and
slope on two aspects in each of four geo-climatically
different hill-farming regions over two years. Pasture
herbage quality at the end of spring followed expected
trends: defoliation to low residual pasture height led
to higher quality herbage. The maximum difference
in quality between the lowest cutting height and nil
cutting at this time was nearly 2 MJME/kg DM. With
a change to uniform cutting height across all plots in
early summer, these pasture quality differences reduced
and disappeared.
Keywords: Pasture quality, hill country, grazing
management
Integrating lucerne (Medicago sativa L.) into a high country
merino system
D. ANDERSON1, L. ANDERSON1, D.J. MOOT2 and G.I. OGLE3
view more
Abstract
Farm systems in the dry sub-humid region of the Upper
Waitaki predominantly graze merino ewes on extensive
oversown and topdressed hill and high country. Smaller
areas of flatter land are used to conserve winter forage
crops, and grow supplementary feed and high quality
pastures. The slow growth rate of merino lambs means
they are traditionally retained on these improved
pastures to finish in the following spring. In this system
livestock demand peaks in the driest month of January
and continues to be high through winter. Bog Roy is a
farm that has changed this system and has established
200 ha of lucerne with the goal of fully feeding ewes
during lactation. Pre-weaning lamb growth rate has
increased from 205 to 235 g/head/day, opening the
opportunity to sell heavier lambs in early January. Ewe
lamb replacements are reaching heavier pre-winter live
weights (38 kg versus 35 kg) and the flow-on effect
is higher two-tooth scanning (129% versus 111%)
and weaning (100% versus 84%). Lucerne has also
improved the feeding of mixed age ewes from lambing
to weaning, and lamb mortality has reduced from 30%
to 21%, increasing weaning from 115% to 130%. The
store production system also means livestock demand
is kept low during the dry period and remains low
through winter. Conserved feed is now only required
for 50 days compared with 100 days in the traditional
system. This has reduced supplementary feed costs
from $10.33/stock unit (SU) to $4.82/SU. Shifting ewes
to rotationally graze lucerne in large mobs early in the
growing season has decreased the stocking rate on hill
country. This has allowed cover to build during each
spring with promising responses from legume species.
Is nitrogen fertiliser an economic option in tussock hill country?
D.R. STEVENS, B.R. THOMPSON, W.D. CATTO, and K.D. TRAINOR
view more
Abstract
Tussock hill and high country is a finite resource.
Farmers are developing these areas to increase
production but often at the expense of tussock which
provides shelter for stock, increases biodiversity and
captures moisture in dry environments. An experiment
at a single hill country site near Roxburgh, Otago was
established on oversown tussock with soil of low pH
(5.1) and high soluble aluminium (15 ppm) to compare
the use of capital lime (0–5 t/ha), annual and capital
superphosphate (0–1000 kg/ha) and annual nitrogen
(N) fertiliser inputs (0–150 kg/ha) over 4 years to
investigate the potential of different fertiliser strategies
to increase economic returns. Annual yield of the
Control without fertiliser was approximately 3200
kg DM/ha/annum, which may support an estimated
stocking rate of 6 ewes/ha during the growing season.
Using lime did not increase the pasture production or
stocking rate, though even small amounts increased
pasture quality. Use of phosphate and sulphur increased
the stocking rate to approximately 9 ewes/ha, while
adding N fertiliser increased potential stocking rate
to approximately 12 ewes/ha. These increases were
a combination of increased pasture production and
increased pasture quality. A combination of phosphate,
sulphur, lime and nitrogen provided a potential net
increase in gross margin of $200/ha. This cost benefit
analysis suggests that regular use of N fertiliser along
with other known fertiliser requirements may be a very
cost effective way of increasing hill country production
without resorting to full scale tussock development.
Keywords: gross margin, hill country, fertiliser, quality,
sheep stocking rate, yield.
Looking back and looking forward - Levy Oration 2013
R.J.M. HAY
view more
Thank you for your kind introduction. What I will
present to you is a perspective of New Zealand Science,
and research funding, from a governance viewpoint, as
well my own take on some of the issues the pastoral
sector is facing. Most emphatically, these are definitely
my views and do not represent those of the Minister or
the Ministry.
Medium-term soil pH and exchangeable aluminium response to
liming at three high country locations
J.L. MOIR and D.J. MOOT
view more
Acid soil conditions and associated aluminium
(Al) toxicity pose a serious impediment to legume
establishment, persistence and productivity in high
country. However, data that report soil exchangeable
Al concentrations in response to lime applications are
scarce. Three historical (3–8-year-old) lime trial soils
were sampled for soil pH and exchangeable aluminium
(Al). Soil pH ranged from 4.8 to 7.5, with exchangeable
Al concentrations (CaCl2 extraction) of 0.2 to 24 mg Al/
kg. Soil pH and exchangeable Al changed significantly
when lime was applied, but the shape of the response
differed between the three site locations. The soil pH
changes (0–7.5 cm horizon) were 0.16, 0.10 and 0.20
pH units/t lime applied. Critical research needs to
be conducted to investigate the key soil factors and
mechanisms that result in Al toxicity in high country
soils to enable development of mitigation strategies.
On-farm decisions on lime rates and legume species
suitability need to be based on soil pH and Al testing
from individual farm blocks rather than using “rule of
thumb” approaches.
Keywords: soil pH, soil exchangeable aluminium,
lime, pasture legumes
Novel approaches to improving growth of pasture legumes
at low phosphorus levels
S.N. NICHOLS and J.R. CRUSH
view more
Abstract
Strategies to reduce the economic and environmental
costs of phosphate (P) fertiliser use in mixed pastures
through plant breeding are focussed on inefficiencies
in the legume component. One approach is breeding
within white clover for root systems with improved
P acquisition properties. Selection for root length per
unit root weight (specific root length, SRL) showed
that higher SRL plants could retain more biomass in the
above ground fraction with decreasing soil P, whereas
plants with lower SRL diverted more biomass to roots.
Back cross 1 (BC1) generation interspecific hybrids
between white clover and a wild relative, Trifolium
uniflorum L., may possess additional root traits
influencing P acquisition. In glasshouse experiments,
some T. repens × T. uniflorum hybrids, back-crossed
to white clover, also exhibited higher shoot dry weight
than their white clover cultivar parents at low nutrient
supply levels and low to intermediate soil Olsen P.
This, combined with low internal P concentrations,
suggests some BC1 hybrids may be more tolerant of
low soil P than white clover. Differences in both P
acquisition ability and internal P use efficiency may
contribute to the observed yield differences. There are
good prospects for delivery of new-generation clover
cultivars with improved phosphate use efficiency to
New Zealand farmers.
Keywords: phosphorus, white clover, Trifolium
uniflorum, interspecific
Nutrient requirements for irrigated lucerne in Central Otago
L.C. SMITH, K.D. TRAINOR and J.D. MORTON
view more
Abstract
Two field trials were commenced in September 2000
on newly sown irrigated lucerne near Tarras in Central
Otago. The first trial measured the effects of phosphorus
(P) (0, 30, 60, 120 kg P/ha) and potassium (K) (0, 50,
100, 200 kg K/ha) fertiliser applications while the
second trial determined nitrogen (N) requirements for
lucerne establishment. Initial soil test levels (0–75
mm) were pH 5.6, Olsen P 15 μg/ml; quicktest (QT)
K 6 and sodium tetra-phenol-boron extractable K
(TBK) 3.1. Lucerne production averaged 9.5 t dry
matter (DM)/ha in the establishment year, 15.6 t DM/
ha in Year 2 and 14.8 t DM/ha in Year 3. There were
no annual DM responses to any of the three fertilisers
applied regardless of the rate of application. Despite
the control mean annual herbage P concentrations
being within the optimum range of 0.20–0.25% the
application of P fertiliser significantly increased the P
concentrations (P<0.001) in Years 1 and 2. The herbage
K concentrations were above required concentrations
(1.5–1.8%) for all harvests, and were only affected
by K fertiliser application in Year 3. The lucerne crop
removed between 300 and 600 kg N/ha/year, 230 to
300 kg K/ha/year and 25 to 40 kg P/ha/year. Biological
N fixation appears to be replacing the N removed as
the lucerne did not respond to applied N and the soil
N levels were maintained throughout the 3 years. The
removal of nutrients such as P and K, to a greater
level than fertiliser applied, under a hay regime has
implications for the longevity of the stand. This is
highlighted for P on the 0P plots with the soil Olsen
P levels dropping to <8 μg/ml for the 0–75 mm soil
layer and <5 μg/ml for the 0–150 mm soil layer by the
third year. Potassium reserves in the soil also declined,
highlighting slow depletion under hay cropping. It
would appear that 0–75 mm Olsen P levels of at least
12–15 μg/ml and 0–150 mm Olsen P levels of 10–12
μg/ml are required for optimum production (95% of
maximum) at this site. Regular monitoring of soil and
plant nutrient levels is recommended to ensure fertiliser
inputs are sufficient to maintain maximum production.
Key words: lucerne, irrigation, nutrient requirements,
phosphorus fertiliser, potassium fertiliser, nitrogen
fertiliser.
Opportunities to improve grazing management
S. McCARTHY, C. HIRST, D. DONAGHY, D. GRAY and B. WOOD
view more
Abstract
Improved efficiency in growing and converting pasture
into product is required to maintain New Zealand’s
competitive advantage in dairying. This study focused
on two areas of grazing management, the first an
assessment of the indicators leaf stage, pre-grazing yield
and grazing residual. In summary, 49% of measured
paddocks were grazed too soon based on leaf stage,
62% were grazed outside the recommended pre-grazing
yield, and 48% of measured paddocks were not grazed
to a desirable height. The second part of the study
provided an insight into farmer decision making at an
operational level of grazing management with three key
components identified. These were: 1) The recruitment
of paddocks into a grazing plan; 2) The shuffling of the
paddock grazing sequence within the grazing plan; and
3) The management of individual grazing events before,
during and after the event. An improved understanding
by rural professionals of grazing management decision
making would result in extension strategies which
generate increased farmer engagement, adoption of
grazing management technologies and improved onfarm
productivity.
Keywords: dairy, grazing management
Perennial lupin establishment and yield when sown at five
different rates at Glenmore Station, Lake Tekapo.
D.J. MOOT and K.M. POLLOCK
view more
Abstract
The potential for perennial lupins to underpin grass/
legume pastures was the subject of a research
programme for merino farmers in areas where more
conventional legumes struggle to thrive. A previously
uncultivated pasture on an acidic soil, (pH 5.0; Al =
5 mg/kg), and dominated by browntop, sweet vernal
and Kentucky bluegrass, was sprayed with herbicide,
burnt and top-dressed with 3 t/ha lime on half the area
in the autumn prior to direct drilling on 12 Dec 2012.
A blue perennial lupin and a multi-coloured (Russell)
lupin were sown at 2, 4, 8, 12, 16 and 32 kg/ha and
cocksfoot at 2 kg/ha. Yield at four months after sowing
had increased with the lupin sowing rate; up to 5.5 t dry
matter (DM)/ha at 32 kg seed/ha. The annual yield for
the following growth season was greater than 10 t DM/
ha with little response above 8 kg lupin seed/ha. There
was a small but inconsistent response to the lime by the
Russell lupin. Overall, lupin contributed 79% of annual
yield and >90% of the spring yield at sowing rates >8
kg/ha. The sown cocksfoot and resident grasses showed
a positive lime response at the lower lupin sowing rates.
Key words: Lupinus perennis, L. polyphyllus
Performance of fodder beet cultivars in the South Island
G.
G.D.MILNE, C. DIREEN, E.KITSON, P. EVANS, R.G.CLELAND and D. TREDER
view more
Abstract
More than 11 cultivars of fodder beet are marketed to
farmers, but with little refereed data on differences in
potential yield. Trials were established in spring 2012
to evaluate the yield, dry matter content of bulbs, and
proportion out of the ground of 13 beet cultivars, at
four sites in the South Island. There were differences
between cultivars for yield, field emergence, dry matter
percentage (DM%) of the bulb, and percentage of
the bulb out of the ground. The cultivars ‘Enermax’
(19.37 t dry matter/ha), ‘Magnum’ (18.98), ‘Bangor’
(17.83), ‘Troya’ (17.54) and ‘Kyros’ (17.39) were more
productive than ‘Brigadier’ (14.00), which was similar
to ‘Feldherr’ (15.15). There were no interactions
between cultivar performance and site. These trials
prove that the selection of cultivar has a large effect on
the yield and profitability of fodder beet crops.
Keywords: Fodder beet, Beta vulgaris, yield, dry
matter, cultivars, fertiliser, disease.
Potassium requirements of pasture on pumice soils
J. MORTON, A. STAFFORD and M. HAWKE
view more
Abstract
On pumice soils at Mamaku near Rotorua (initial quick
test (QT) K 4) and Pouakani near Whakamaru (initial
QT K 2), pasture yield responses to applications of
0, 75, 150, 300 and 600 kg K/ha/yr (all as three equal
split applications) plus 300 kg K/ha/yr applied once
in the spring were measured for 3 years. There was a
significant total pasture dry matter (DM) response to up
to 150 kg K/ha/yr at Mamaku in two and to 75 kg K/
ha/yr in one of the first three years, but no significant
difference (P<0.05) between 300 kg K/ha/yr applied
once or as split applications. The contribution of clover
to DM yield was increased significantly by up to 75 kg
K/ha/yr in the second year and 150 kg K/ha/yr in the
third year. In the fourth year when a common rate of
130 kg K/ha was applied to all of the K plots, there
was a significant pasture and clover DM contribution
response up to the previous 300 kg K/ha/yr at Mamaku.
At Pouakani there was a significant pasture yield
response to up to 300 kg K/ha/yr in the second and
up to 75 kg K/ha/yr in the third year. There was no
significant difference in pasture yield between a single
spring application and three split applications of 300 kg
K/ha/yr. Clover contribution to DM yield was increased
significantly by up to 300 kg K/ha/yr in all of the first
three years. In the fourth year, there was no significant
difference in pasture DM yield between previous K
treatments, but a carryover effect on clover contribution
to pasture DM yield. Pasture relative yield (RY) was
lower than the average derived from other trials on
pumice soils at the same soil QT K levels and nearmaximum
pasture yield (97% RY) was achieved at a
lower soil QT K level (3–4) for these sites than for the
overall average (5) . It was concluded that at these low
QT K levels, high rates of K are required for maximum
pasture production on pumice soils but these may not be
economic. These higher rates of K increased soil QT K
levels above the target range for near-maximum pasture
production (7–10) at the end of the growth season, only
for it to drop to below this range by the next spring
because of high winter leaching rates. Therefore on
those pumice soils where it is difficult to achieve the
target range for soil QT K, it is recommended that K be
applied at least three times in a growth season to ensure
an adequate supply from fertiliser.
Potassium requirements of pasture on pumice soils
J. MORTON1, A. STAFFORD2 and M. HAWKE3
1 Ballance Agri-Nutrients, PB 2290, Hastings
2 Ballance Agri-Nutrients, PB 12503, Tauranga
3 MFH Consultancy, RD 4, Rotorua
jmorton@ballance.co.nz
Keywords: pasture yield response, potassium, soil
quick test potassium, pumice soils
Productivity and seedling recruitment of naturalised
annual clovers versus sown clovers Trifolium repens and
Trifolium subterraneum
T.M.R. MAXWELL, J.L. MOIR and G.R. EDWARDS
view more
Abstract
Naturalised annual clover (NAC) species (suckling
clover, cluster clover, striated clover, and haresfoot
clover) are commonly present to locally abundant in
summer dry hill and high country areas where white
and subterranean (sub) clover abundance is limited.
This field trial investigated NAC species dry matter
production and seedling regeneration compared to
white and sub clover. Autumn seedling recruitment was
measured in response to low (75 kg/ha) or high (200 kg/
ha) superphosphate (SP) application. Over two growing
seasons, NAC species contributed >90% to pasture
legume content while white and sub clover contributed
<10%. Striated, suckling, and cluster clovers showed
greater recruitment under low SP with 996, 978, and
227 seedlings/m2 respectively compared to high SP
with 635, 466, and 123 seedlings/m2 respectively.
Collectively, NAC species were superior to white and
sub clover on north-facing slopes. Spreading NAC
species seed via livestock dung dispersal and aerial
broadcasting would further increase their contribution
to total pasture DM and nitrogen input.
Keywords: annual legumes, striated clover, Trifolium
striatum, cluster clover, T. glomeratum, suckling
clover, T. dubium, white clover, subterranean clover,
superphosphate, phosphorus, sulphur, seedling
recruitment, hill and high country.
Rising plate meters and a capacitance probe estimate the biomass
of chicory and plantain monocultures with similar accuracy as for
ryegrass-based pasture
J. HAULTAIN, K. WIGLEY and J.M. LEE
view more
Abstract
It is useful to gain an estimate of herbage biomass when
feed budgeting. However, none of the tools that are
available to estimate biomass (e.g., the rising plate meter
(RPM) or capacitance probe (CP)) have been tested on
popular forage herbs, such as chicory or plantain. We
tested the hypothesis that RPM and CP could be used to
estimate biomass of first year pure chicory and plantain
swards with accuracy at least as great as for ryegrassbased
pasture. In two summer experiments at different
locations in the Waikato, RPM, CP and uncompressed
sward height (SH) readings were taken throughout
regrowth within 0.2 m² quadrats in chicory and plantain
swards, and ryegrass-based pasture. The herbage was
then cut to ground level and oven-dried to estimate
biomass. Linear equations relating biomass to mean
readings were generated for each method, both within
each experiment and as pooled datasets. In ryegrassbased
pasture, the correlation coefficients (R²) were
0.73, 0.43 and 0.51 for RPM, CP and SH, respectively.
For chicory swards, the pooled correlation coefficients
(R²) were 0.73, 0.73 and 0.81 for RPM, CP and SH,
respectively, while for plantain swards the R2 were
0.70, 0.59 and 0.68 for RPM, CP and SH, respectively.
This led to the conclusion that the RPM was a suitable
tool for the estimation of biomass in pure chicory or
plantain swards as it had similar accuracy to calibration
equations for ryegrass-based pasture.
Farmers, at least in the Waikato, can estimate first
year chicory or plantain biomass through the summer
and autumn period using the following equations:
Chicory biomass (kg DM/ha) = 86 × RPM reading +
235, or = 0.64 × CP reading + 437, or = 94 × SH - 190.
Plantain biomass (kg DM/ha) = 94 × RPM reading
+ 455.
Keywords: rising plate meter (RPM), capacitance
probe (CP), chicory, plantain
Sheep performance on perennial lupins over three years at
Sawdon Station, Lake Tekapo
A.D. BLACK, G. LOXTON, T.P. RYAN-SALTER and D.J. MOOT
view more
A three-year trial compared the performance of Merino
ewes grazing on a perennial lupin pasture with a control
flock run predominantly on lucerne pastures at Sawdon
Station, Lake Tekapo. At tailing in December, lambing
averaged 111% and ewes averaged 58 kg for the lupin
pasture, and 105% and 62 kg for the control flock,
while lambs averaged 19 kg for both mobs. At weaning
in February, ewes and lambs on the lupins averaged 58
kg and 28 kg compared with 63 kg and 31 kg for the
control flock, and ewes gained 3.8 kg compared with
5.5 kg from March to mating in May. In September,
wool averaged 4.62 kg/ewe for the lupin mob and 4.92
kg/ewe for the control flock, with a mean fibre diameter
of 18.5 μm. The average herbage mass on the lupin
pasture was 3.0 t dry matter (DM)/ha at the start of
lambing in October, reached 7.8 t DM/ha in December
and decreased to 3.5 t DM/ha in May. Results support
the use of perennial lupins where lucerne fails to thrive
on high country farms.
Keywords: high country, liveweight gain, Lupinus
polyphyllus, Merino
The chemical composition of high-sugar and control ryegrasses in
grazed pastures at different latitudes throughout New Zealand
G.P. COSGROVE, N.R. MAPP, P.S. TAYLOR, B.M. HARVEY and K.J. KNOWLER
view more
Abstract
Extrapolating from single-site animal studies of the
effects of water soluble carbohydrate (WSC) on
methane and nitrogen emissions requires knowledge of
geographical and temporal variation in plant chemical
constituents. To provide this, samples of grazed pasture
were collected from experiments at four different
latitudes over one year. At each site, one high-sugar
perennial ryegrass (HSG) and two control cultivars of
perennial ryegrass, were sampled at each grazing during
a 12-month period and analysed for concentrations of
WSC, crude protein (CP) and fibre (NDF). Compared
with the controls the HSG was higher in WSC (overall
mean 299 vs 260 g WSC/kg DM; P<0.01 at each site),
lower in NDF (426 vs 460 g NDF/kg DM; P<0.01 at
each site) but did not differ in CP. There were significant
differences among sites (P<0.001) with highest
concentrations of WSC in Canterbury followed by
Southland, Waikato and Manawatu (295, 278, 266 and
254 g WSC/kg DM, respectively). Concentrations of
WSC were highest in spring and approximately double
those in autumn. Animal responses to cultivars with a
higher concentration of WSC will be tempered by these
large natural variations, which must be accounted for
when extrapolating or scaling-up to regional or national
outcomes.
Keywords: water soluble carbohydrate, perennial
ryegrass, protein, fibre, latitude, variation
The economics of transformation toward sustainable hill country
land use: Whatawhata case study
M.B. DODD, W. CARLSON and P. SILCOCK
view more
Abstract
The Whatawhata integrated catchment management
project generated a substantial amount of data on the
biophysical impacts of land use and management
change – livestock enterprise performance, terrestrial
biodiversity, water quality etc. The question has been
posed: What was the impact of the changes on the
financial viability of the catchment farm system? Farm
operating budgets before and after land use changes,
enterprise gross margins, costs associated with tree
planting, and farm system modelling with FarmaxPro®
have been integrated to give a whole-system view of
farm business viability over the long term (1995–2030).
This information compared the existing system (1990s)
with the new system implemented in 2000. Annual
operating profit for the 296 ha breeding ewe and
breeding cow system in the late 1990s was between $25
000–$30 000 reflecting the size and land use capability
distribution of the block. Changes to the livestock
enterprises improved farm surplus from ca. $100/ha to
ca. $330/ha in the first 3 years, but on a reduced pastoral
land area (150 ha). This gave an annual operating profit
(EFS) of ca. $50 000. Much of this difference reflected
product price movements. The cost of land use change
was approximately $969 000 over the first 10 years.
Selective intensification of hill lands can improve per
ha profitability in the short-medium term. Two key
financial issues, the transformation cost and medium
term viability, need to be addressed in implementing
land use change to move toward hill land sustainability.
Keywords: integrated catchment management, land
use change, sustainable hill country
The production and water extraction of lucerne and ryegrass under
different irrigation frequencies on a shallow soil.
A.J. MICHEL, H.E. BROWN, E.I. TEIXEIRA, E.D. MEENKEN, S. MALEY, M.J. GEORGE and R.N. GILLESPIE
view more
Abstract
A field experiment was conducted on a shallow
soil (low plant available water holding capacity) at
Lincoln (Canterbury, New Zealand) to compare the
biomass production of lucerne (Medicago sativa L.)
and perennial ryegrass (Lolium perenne) under four
different irrigation frequencies: (T1) replacing water use
(WU) twice a week (replicating centre pivot rewetting
frequencies); (T2) replacing WU fortnightly (replicating
travelling irrigator); (T3) replacing WU every 3 weeks
(replicating border dyke); (T4) nil irrigation (rain fed
only). Soil water content was measured hourly at 0–30
cm depth and fortnightly at 0–150 cm depth. Plots were
sown in March 2011 and defoliated on eight (ryegrass)
and five to six (lucerne) occasions each season between
September 2011 and May 2014. Annual biomass
production during the first year was highest for ryegrass
under each treatment because the lucerne crops were
still establishing. During the second and third year of
experimentation ryegrass yielded higher or similar to
lucerne under the irrigated treatments (T1, T2 and T3).
This was attributed to a decline in lucerne stands due to
weed pressure. It is important to note that the ryegrass
crop has received 250–700 kg N/ha per year depending
on the irrigation treatment. Under dry conditions (T4)
ryegrass yielded more than lucerne in both year 2 and
3. This result contrasts the literature and is attributed
to the greater capacity of ryegrass to grow in cooler
season and the stony sub-soil meaning lucerne received
no summer yield advantage from its deep tap root.
Key words: Medicago sativa L., Lolium perenne,
biomass, water extraction, irrigation frequency
The rise to dominance over two decades of Lupinus polyphyllus
among pasture mixtures in tussock grassland trials
D. SCOTT
view more
Abstract
In two trials near Lake Tekapo, one started from
sown binary mixtures of 14 different legumes, of
which Lupinus polyphyllus was one, was cross sown
with 16 different grasses, while in the other trial L.
polyphyllus and Trifolium hybridum were over-drilled
across established swards of previous 25 different grass
and legume species. In both L. polyphyllus persisted,
increased and spread by seeding in the presence of
repeated mob grazing by sheep to become the dominant
species over two decades.
Keywords: New Zealand, rangeland pasture development,
Lupinus polyphyllus, Bromus inermis.
The rise to dominance over two decades of Lupinus polyphyllus
among pasture mixtures in tussock grassland trials
D. SCOTT
view more
Abstract
In two trials near Lake Tekapo, one started from
sown binary mixtures of 14 different legumes, of
which Lupinus polyphyllus was one, was cross sown
with 16 different grasses, while in the other trial L.
polyphyllus and Trifolium hybridum were over-drilled
across established swards of previous 25 different grass
and legume species. In both L. polyphyllus persisted,
increased and spread by seeding in the presence of
repeated mob grazing by sheep to become the dominant
species over two decades.
Keywords: New Zealand, rangeland pasture development,
Lupinus polyphyllus, Bromus inermis.
Variation in the reproductive development of perennial ryegrass
(Lolium perenne L.) cultivars
C.M. WIMS, J.M. LEE, L. ROSSI and D.F. CHAPMAN
view more
Abstract
Plant breeding has manipulated the flowering
behaviour of perennial ryegrass (Lolium perenne L.)
by developing later-heading cultivars. However, the
impacts of breeding on the intensity and temporal
distribution of flowering are not known. This study
compared the reproductive development of 23
perennial ryegrass cultivar/endophyte combinations. In
the Waikato and Canterbury, two replicate plots were
closed from grazing and tillers were collected every
two weeks over a 10-week period during late spring and
early summer. Plant development stage was determined
for each tiller using a quantitative scale, which was then
used to calculate the mean stage count of each cultivar.
The rate and timing of reproductive development
differed among cultivars. Mid-maturing cultivars
matured earlier at both sites compared with late- and
very late-maturing cultivars. While the intensity of
flowering was similar between maturity groups, the
temporal distribution of flowering varied: the late- and
very late-maturing cultivars had lower proportions of
reproductive tillers early in the season.
Keywords: Lolium perenne L., reproductive
development, flowering behaviour
Variation in the reproductive development of perennial ryegrass
(Lolium perenne L.) cultivars
C.M. WIMS, J.M. LEE, L. ROSSI and D.F. CHAPMAN
view more
Abstract
Plant breeding has manipulated the flowering
behaviour of perennial ryegrass (Lolium perenne L.)
by developing later-heading cultivars. However, the
impacts of breeding on the intensity and temporal
distribution of flowering are not known. This study
compared the reproductive development of 23
perennial ryegrass cultivar/endophyte combinations. In
the Waikato and Canterbury, two replicate plots were
closed from grazing and tillers were collected every
two weeks over a 10-week period during late spring and
early summer. Plant development stage was determined
for each tiller using a quantitative scale, which was then
used to calculate the mean stage count of each cultivar.
The rate and timing of reproductive development
differed among cultivars. Mid-maturing cultivars
matured earlier at both sites compared with late- and
very late-maturing cultivars. While the intensity of
flowering was similar between maturity groups, the
temporal distribution of flowering varied: the late- and
very late-maturing cultivars had lower proportions of
reproductive tillers early in the season.
Keywords: Lolium perenne L., reproductive
development, flowering behaviour
Water use efficiency of fodder beet crops
E. CHAKWIZIRA, J.M. DE RUITER, S. MALEY, S.J. DELLOW, M.J. GEORGE and A.J. MICHEL
view more
Abstract
In New Zealand, summer rainfall is unpredictable and
usually insufficient to meet crop water requirements.
The impact of water availability on yield potential of
fodder beet (Beta vulgaris L.) is unknown. A single year,
single site replicated field experiment investigating
biomass production, water use (WU) and water use
efficiency (WUE) was carried out on a deep Templeton
silt loam soil at Lincoln in 2013. The experiment had
four water treatments: 1: Rain fed control, 2: Full
potential evapotranspiration (ETo) replaced weekly, 3:
50% of ETo replaced every 3 weeks and 4: 50% of ETo
replaced weekly. Final dry matter (DM) yield differed
with treatments, increasing from an average of 24 t/ha
for the rain fed crops and those receiving 50% of ETo
weekly to 28 t/ha for the full ETo replacement crops and
those receiving 50% of ETo once every 3 weeks. Water
use more than doubled with full irrigation compared
with the rain fed crops (774 vs 316 mm). The WU for
the intermediate crops was 483 mm. However, DM
yield was higher for the treatment with 50% of ETo
replaced every 3 weeks rather than weekly. Water use
was related to DM yield and accounted for the observed
variation (R2=0.75) in final yield. The WUE decreased
with water supply, from 80 kg DM/ha/mm for the
rain fed crops to 46 kg DM/ha/mm for the full ETo
replacement treatments, and 64 and 57 kg DM/ha/mm
for the 50% of ETo replaced weekly and every 3 weeks,
respectively. Similar DM yield and marginal WUE for
the full ETo treatments and those receiving 50% of ETo
replaced every 3 weeks, meant that the most economic
WUE was 57 kg DM/ha/mm. Although these results
are from a single and site, they suggest that full ETo
replacement was uneconomic in this type of soil and
therefore partial irrigation to 50% of ETo replaced every
3 weeks may be the optimum for this type of soil. It
is recommended to investigate similar treatments on
shallow and stony soils.
Keywords: Beta vulgaris L., evapotranspiration, water
use, water use efficiency, water extraction pattern,
water extraction depth.
Yield and composition of lucerne stands in Central Otago after
different winter grazing and weed control treatments
M. ROUX, S.K. LEASK and D.J. MOOT
view more
Abstract
The effect of grazing date and time of spraying with a
glyphosate/atrazine herbicide combination on a threeyear-
old lucerne stand was studied on-farm in Central
Otago. Total annual dry matter (DM) yield was highest
in the weedy unsprayed control (14.8 t DM/ha) and
lowest in the crop sprayed on 18 September (10.1 t DM/
ha). However, lucerne DM yield was highest from the 3
July and 22 August spray treatments (11.4 ± 0.39 t DM/
ha) and lowest in the unsprayed control at 7.7 t DM/ha.
Phytotoxicity symptoms of glyphosate on the lucerne
tended to be limited to crops sprayed on 18 September.
To maximise yield, a winter clean-up grazing (June)
followed by a winter herbicide application (July/August)
when lucerne was approximately 3 cm high and with
<100 kg DM/ha was required. After this, grazing earlier
than October should be avoided as a September grazing
resulted in a lucerne yield of about 1.0 t DM/ha less
than grazing in October and November. Spring lucerne
production was delayed by spraying in September.
None of the spray treatments killed the crop, but they all
reduced weed content from about 40% to <1%.
Keywords: alfalfa, atrazine, glyphosate, lucerne,
Medicago sativa L., phytotoxicity, weed control, winter
grazing, yield.
Download
(451 KB)
