The financial profitability of these sheep is dependant on the extra money obtained from the much bigger and more numerous lambs, because the dams clip about 32kg, or $5 worth of wool less than a longwool fleece. Compared with NZ’s average Romney producing 4.5kg wool and 1 lamb, the Border Dorsets have produced 3.2kg wool and 1.33 lambs and each carcase weight is 2kg heavier.
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(43 KB)Clover cyst nematode (Heterodera trifolii Goffart, 1932) and root knot nematode (Meloidogyne spp.) were found throughout summer-dry hill country in the North Island. Clover cyst nematode was found at 50% of sites in the corresponding South Island hill country regions sampled but no root knot nematode was found at South Island sites. The implication for white clover breeding programmes is discussed. Keywords: Pasture, dry hill country, clover cyst nematode, root knot nematode, Heterodera trifolii, Meloidogyne sp., white clover, Trifolium repens.
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(96 KB)Temperate grasses were introduced mto kikuyu-based dairy pastures to Improve poor winter and spring growth rates. Methods of suppressing resident pasture growth before sowmy included, forage harvesting, hard grazmg and paraquat spraying (0.44 kg al/ha). Seed was either broadcast sown or direct drilled. ‘Grasslands’ cultwars Tama and Nui ryegrass and Matua prairie grass were used. Tiller densities, dry matter production and pasture cornposItIon were measured at 3 to 8 week Intervals in three trials rangmg from 8 to 24 months duration. Hard grazing or forage harvesting did not differentially affect subsequent pasture productlo” Establishment of Tama was best after paraquat spraying and then direct drilling. Sprln~ dally growth rates rose from 25 kg DM/ha in ktkuyu pasture to 56 kg DM/ha in pasture direct dnlled wth Tama after paraquat spraying. but pasture growth rates were similar in early summer once Tama died. Early autumn sowing of Tama is likely to give poor establishment if kikuyu IS not severely suppressed, and late autumn sowing will contribute llttle to winter productjon. In another trial Matua increased annual productlon through better autumn, wmter and sprmg growth. Nui and Tama both improved growth rates rn wrnter and sprmg, but only Nui increased annual productjon also. Keywords: Kikuyu, Nui, Matua, Tama, establishment, paraquat, herbage production, direct drilling.
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(95 KB)Increasing material, processing, and distribution costs have raised superphosphate prices to a point where many farms cannot support the costs of meeting maintenance phosphate requires men& Alternatives to superphosphate, particularly those that have lower processing costs and contain more P, may offer a solution to the problem provided they are agronomically as effective. Phosphate rock may indeed be such an alternative. Preliminary results from a series of five trials in Northland show that on soils of moderate P fertility, with low phosphate retention (PR) and high pH (5.9.6.0), initial pasture growth responses to rock phosphates are smaller than those from single or triple superphosphate. On one soil of higher PR and lower pH, the differences in yield between the rock-phosphates and the super. phosphates were smaller. Of the rock phosphates tested, Sechura and North Carolina (unground and ungranulated) tended to be more effective than ground and granulated Chatham Rise phosphorite. The effect on production of applying fertilisers once every three years, as opposed to annual applications is being investigated using triple superphosphate and Sechura phosphate rock. After two years, production levels appear largely unaffected by differences in application frequency. A comparison of locally-produced superphosphate with a reference standard showed that both performed similarly, indicating that the local product was of satisfactory quality.
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(64 KB)Fertilisers based on or enriched by reactive phosphate rock (RPR) compare favourably in price with superphosphate under certain conditions. The ultimate choice of fertiliser depends on three factors:- the agronomic effectiveness of phosphorus in RPR in different soils; the sulphur requirements of pasture and the effect of this on price; and the effect of high proportions of potassium chloride on the physical properties of fertilisers. The rate of dissolution of RPR is reduced by high pH and high P and Ca concentrations in the ambient solution. The so-called gumland soils, recognisable by their bleached subsoIls, have higher P and Ca concentrations in the soils solution than other soils in Northland, pH and P status being equal. They also tend to lose more sulphate by leaching than other soils, so maintenance of requirements of their pastures for sulphur are very high. In addition many of the gumland soils need low rates of phosphorus but relatively high rates of potash. Pending further field evidence, therefore, RPR based or :einforced fertilisers at present are recommended for hill country and for soils derived from basic or semi-basic volcanic materials, provided the latter soils do not require a very high proportion of potassium chloride for pasture maintenance. Keywords: Soil pH, calcium, phosphorus, pasture, organic matter, sulphur, potassium, superphosphate, phosphate rocks.
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(130 KB)Interest in high analysis sulphur (S) fertilisers is centred on elemental S which is generally mixed with other materials for safety reasons and to improve effectiveness. Central to the effectiveness of S fertilisers is the rate of oxidation to sulphate-S (SO4S)) for plant uptake. Oxidation rates increase as particle fineness increases. The distribution of S particle sizes in mixtures therefore affects the effectiveness of the fertiliser in any environment. Rates of oxidation vary between environments and thus different S particle size distributions suit different environments. Currently the choice of alternative commercial available S fertilisers is restricted to screened ‘agricultural’s” and mixtures of S” with superphosphate. Of these, molten mixed S superphosphate is the most suitable material for most environments but especially where S oxidation is slow. Commercial production of alternative S” fertiliser mixtures in New Zealand is imminent. Mixtures of S and sodium bentonite offer the possibility of preparing fertilisers to suit different environments. Granulated ground S” mixed with bentonite clay can be expected to release SO4-S more slowly but this has advantages where leaching of sulphate is likely. Production of SO4-S from two improved Canadian S/bentonite materials is expected to be similar to or slower than that from granulated ground S. Two other imported products, S impregnated urea (20% S, 36%N) and ‘Thiovit’ (85%S) contain finely divided and ultra finely divided S” respectively. They are raptdly and very rapidly oxidised to sulphate and may have specialised uses in cropping and horticultural enterprises. Keywords: Sulphur fertilisers, elemental sulphur, sulphur/sodium bentonite, plant sulphate, oxidation rates
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(209 KB)Tall fescue is the most important cool-season pasture species in the transition zone of the southeastern U.S.A., occupying more than 10 million hectares. Forage quality indices such as crude protein, in uitro digestibility etc. Indicate that tall fescue should be capable of stimulating high animal performance. Nevertheless since its widespread introduction in the early 1950’s, tall fescue has been associated with a myriad of animal production problems. Recently researchers have been able to associate poor animal performance with an endophytic fungus present in the plant tissue of tall fescue. The history and current situation in the U.S. with respect to the endophyte of tall fescue and its influence on economic animal production are discussed. Keywords: Tall fescue toxicity, endophyte, Summer Syndrome, ocremonium coenophialum.
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(90 KB)Progress in the development of autumn and winter lambing systems in Northland is described. Both involve split flock lambing in which 30 or 15% of ewes lamb in autumn or winter respectivelv, the remainder in spring. Using progesterone priming, a high ram to ewe ratio (10%) and ram management, 80.90% of ewes joined lamb over 2 cycles. Winter lambing using cull ewes is simple and does not require a breeding programme. Ewes and their lambs can be sent to the meat works from September. For low cost lamb production with present breeds, autumn lambing requires a breeding programme to develop spring mating ability. Heavyweight(18kg)carcasses can be produced early in the killing season. Autumn born replacement ewe lambs consistently averaged 40kg before their first summer. Both systems offer more flexibility in sheep production on farms and in processing and marketing. Keywords: Autumn lambing, winter lambing, split lambing, management options, extending killing season, heavyweight lambs production
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(105 KB)Low summer production in Northern Northland can be largely overcome by the use of ‘Grasslands Pawera’ red clover. Daily dry matter production of 100+ kg/ha/day over the penod late October to early March, have been recorded over two years. Yearly production of 22,OOOkg DM/ha in the first year, and 17,500 to 21,000 in the second year, have been recorded from pure stands of Pawera. This growth is of very high quality occurring at a tlmc when growth and quality of existing Rye or Kikuyu based pastures, are low. Potential problems from the use of Pawera are discussed. Keywords: Pawera red clover, quality, Northland, problems.
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(86 KB)Despite the use of molybdenum on New Zealand pastures for 30 years the diagnosis of molybdenum deficiency is not easy nor is it clearly understood. In this paper we show how a knowledge of the function of molybdenum and factors that affect the molybdenum concentration in plants can be used to make a confident assessment of pasture molybdenum status. The MAF recommended rate of application of molybdenum has been reduced to 50 g/ha sodium molybdate every four years and the basis for this change is discussed. Keywords: molybdenum, trace elements, nitrogen fixation, pastures, clover, topdressing.
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(186 KB)Land use change has been commonplace in Northland during the 1970s and early 1980s. The region illustrates better than any other both the adjustments to pastoral farming and the diversification of land use that are observable in many parts of New Zealand. Most of the changes in land use are well known. The expansion of exotic forestry is visible and controversial, horticultural diversification has received considerable publicity, and the commercial potential of goat farming has also attracted attention in the region. The emergence of specialised beef farms, often in conjunction with part-time farming, has received less attention. Although the changes in land use are recognised, their extent and the processes by which they have come about are less well understood. This paper establishes the dimensions of the land use changes in Northland and identifies aspects of the decision making of the individuals and corporations involved in the changes. Much of the data on which this discussion is based are derived from a series of theses and research reports completedin the Department of Geography, University of Auckland, (Kearns 1982; Wheeler 1982; Anderson and Moran 1983; Kearns and Moran 1984; Hardy 1985; Revington 1984; Wheeler and Moran 1985; Maunier, Moran and Anderson 1985).
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(91 KB)Earthworm populations were measured in hill pastures, near Woodville, which were rotationally
grazed or set stocked by sheep, or rotationally grazed by cattle. For each grazing
management there were two fertiliser treatments: high and low superphosphate application, and
sampling sites were located within each of three slope and three aspect classes. Earthworm
weight was greater in sheep-grazed than in cattle-grazed areas (91 vs 45 s/r+), was higher in
high than in low fertiliser areas (93 vs 75 g/mz), and declined with increasing slope of measurement
site. There was also a greater number of earthworms in sheep~grazed compared with
cattle~grazed areas (645 vs 270/n+), earthworm numbers declined with slope, and aspect
influenced earthworm numbers (SW Effects of late-May/early June application of fertiliser nitrogen (N) on pasture and animal
performance from hill pastures, were measured durmg 1982.1984 on four 10 ha farmlets at
Ballantrae Research Area near Woodville. Two farmlets had a history of high superphosphate
(375 kg/ha/year) application and were stocked at 16.1 ewes/ha and two farmlets that received
less superphosphate (125 kg/ha/year) were stocked at 12 ewes/ha. Urea was applied at rates
equivalent to 3kg N/ewe, or 50 and 37kg N/ha/year respectively on one high fertiliser and one
low fertiliser farmlet. Pasture production responses were large and reliable (range of 17 to 34,
average of 28kg DM/kg N), and extended through winter into spring. Average legume content
of pastures was depressed from 12 to 8% by N applicahon. Ewes were heavier in winter and
spring where N was applied, but not at mating in April/May. Lambing performance was similar
across farmlets, but weaned lamb liveweight was 14% higher where N was applied. Nitrogen use
resulted in 6% greater ewe wool production and 12% greater lamb wool production. Profitability
of N use would have been enhanced if utilisatlon of N-boosted pasture had been greater, more
responsive stock classes used, or application of superphosphate reduced temporarily.
Keywords: Hill country, North Island, hill pastures, urea, fertiliser nitrogen, sheep production.
wool production, lamb produchon, profItabIlity. SolI from subsurface wormcasts and from the lining of earthworm burrows had more water
soluble phosphate than the surrounding soil at all soil depths sampled down to 250mm. The
absolute effect of earthworm presence on water soluble phosphate concentration decreased
markedly with depth.
While earthworms increase soluble phosphate concentration down the soil profile, the
availability of the redistributed phosphate is somewhat attenuated with depth, probably
through its being resited in soil of greater phosphate absorbing power than that of the surface.
Keywords: Earthworms, avatlable phosphate, phosphate distribution A flock of 370 Dorset x Romney ewes with up to 96% autumn lambtng was developed without
the aid of hormones. Data from flock and experimental records were used to compare the
performance of autumn- and spring-born lambs and their dams. Preliminary findings for three
seasons show that ewes lambed in autumn had a greater spread of lambing, lower litter size and
fewer perinatal lamb deaths. Growth of suckling lambs was similar in winter and spring. After
weaning, autumn-born lambs grew faster than spring~born lambs of the same age (104 v 34
g/hd/day). The proportion of lambs reaching killable weights by January was 90% and 10% for
autumn and spring lambs respectively.
Keywords: Lambing time, autumn, spring, lambing performance, lamb liveweight gain. Advisory Services Division has promoted and co-ordinated a problem solving approach to
facial eczema. Results from the workshop provide a good example of the achievements
possible when experience skills and knowledge are pooled.
The support enthusiasm and action of the workshop participants has resulted in a strategic
plan to arrive at a clearly defined goal. Objectives have now been selected to substantially
reduce losses for the Regions most serious animal disease.
Keywords: Facial eczema, damage, attitudes. control strategies, problems Facial eczema is the most important mycotoxin affecting New Zealand lIvestock. It is a
partrcular problem in the lower lying warmer and morster areas of the northern North Island
where conditions are favourable to rapid fungal growth and sporulation during autumn. In
severe years animal deaths and depressed production can lead to losses exceeding $60 mlllion,
average losses are estimated to exceed $20 million anually. Production losses. especially
despressions in ewe fertility, can occur in the absence of clinical symptoms so most farmers
grossly underestimate the financial losses Inflicted by this disease. Research has led to a
number of control methods includmg the identification and awldance of toxic pastures,
fungicides, zinc dosing and selection for more resistant stock. However these are not widely
accepted by the farming industry because of costs, high labour requirements and a disinclination
to disturb normal management practices.
Keywords: facial eczema, control, productlon losses, resistance, zinc, fungicides. The fungal saprophytes, Pithomyces chartorum and Fusorium culmorum, have similar
distribution patterns in grazed-pasture ecosystems. Spore loads (and toxin levels) of each are
highest at the base of pastures and rapidly decline up the profile. But variation is considerable
from site to site within a pasture, with the highest levels associated with high N (viz: urine-patch)
sites.
In vegetative tillers of ryegrass the fungal endophyte, Acremonium lolii, has a similar vertical
distribution pattern to the above-mentioned saprophytes, the greatest concentration being in
the leaf sheath component in the pasture base. It also develops better within ryegrass at high N
sites.
Grazed-pastures are not uniformly defoliated by livestock during summer and autumn -
urine-patch sites are grazed more frequently and intensively and dung-patch sites less frequently
and intensively than the remainder of a pasture, especially when set-stocked. The close grazing
which occurs at urine-patch sites, especially in grass-dominant pastures can, therefore, contribute
disproportionately to the acquisition of fungal toxins by livestock.
Observations of field outbreaks and results of grazing experiments show that the risk of
outbreaks of ryegrass staggers in sheep is greater under set-stocking and during the latter stages
of defoliation of a pasture in a rotational system. When necessary defoliation, especially at urinepatch
sites, and hence acquisition of fungal contaminants (and toxins), can be controlled
adequately by a rapid rotation in which stock are moved daily. Moving stock less frequently does
not control defoliation or the development of dietary-dependent disorders.
Keywords: Pasture fungi, saprophytes, ryegrass endophyte, distribution patterns, feeding
behaviour, toxin acquisition, dietary-dependent disorders, facial eczema, ryegrass staggers,
ill-thrift, infertility, grazing management and control. G18 white clover (trifolium repens L.), a larger leaved, more upright growing clover than
‘Grasslands Hula’and’Grasslands Pitau’, has been bred for intensive lowland farming, particularly
dairy farms. It originated from crosses between ‘Grasslands Pitau’ and Ladino plants,
selected in soil infested with stem nematode (Ditylenchus dipasci (Kuhn) Filipjev).
G18 has produced more than both Pitau and Huia in trials in Northland and Manawatu Total
pasture production has often been similar for the three cultivars, but clover DM has increased
25.84% over four years compared with a Huia pasture in Northland, the superiority being
greatest under laxer rotational grazing. G18 has persisted well, even after more than 3 1/2 years of continuous sheep grazing, with some spells for yield cuts.
Keywords: white clover, Trifolium repens L., G18, Ladino, Pitau, stem nematode, production,
persistence. Dairying, sheep and beef farming have financed the regional growth and
development of Northland this century. There are now well over a million dairy and
beef cattle grazed in the nine counties of the North Auckland peninsula, and with sheep
approaching 3 million, total farm gate sales from pastoral industries, last year, were
close to $400m. Dairying continues as the predominant revenue earner, contributing
two thirds of this total. Endophyte infection is widespread in grasses and in many instances is associated with insecf
resistance. This resistance appears to be due to chemical components produced in the infected
grasses. Ryegrass, infected with Acremonium folioe endophyte contains peramine, a feeding
deterrent to stem weevil, Listronotus bonariensis. Other examples of endophyte-associated
insect resistance are discussed and the mechanisms of this insect resistance are briefly
compared with those mechanisms implicated in producing animal toxicity problems.
Keywords: endophyte, insect resistance, ryegrass, tall fescue, insect feeding deterrents,
animal toxins, alkaloids. Download
(76 KB)
EFFECTS OF LATE-AUTUMN NITROGEN
APPLICATION ON HILL COUNTRY PASTURES
AND SHEEP PRODUCTION
M.G. LAMBERT and D.A. CLARKview more
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(91 KB)
ENHANCEMENT OF SOLUBLE PHOSPHATE
IN THE SOIL PROFILE BY EARTHWORMS
M.C.H. MOUAT and R.G. KEOGHview more
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(112 KB)
EWE PERFORMANCE AND LAMB LIVEWEIGHT
GAINS COMPARED FOLLOWING AUTUMN
AND SPRING LAMBING
I.P.M. McQUEENview more
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(69 KB)
FACIAL ECZEMA - A STRATEGIC APPROACH
R.D. THOMSONview more
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(49 KB)
FACIAL ECZEMA - PROBLEMS AND
SUCCESSES IN CONTROL
N.R. TOWERSview more
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(92 KB)
FUNGAL DISTRIBUTION AND LIVESTOCK
DEFOLIATION PATTERNS IN PASTURE
ECOSYSTEMS, AND THE DEVELOPMENT AND
CONTROL OF DIETARY-DEPENDENT
DISORDERS
R. G. KEOGHview more
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(229 KB)
G18 WHITE CLOVER - A NEW CULTIVAR
FOR LOWLAND PASTURES
J. VAN DEN BOSCH, J.A. LANCASHIRE,
B. M. COOPER, T. B. LYONS,
W. M. WILLIAMSview more
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(75 KB)
GRASSLAND FARMING IN NORTHLAND
J.D. CURRIEview more
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(118 KB)
INSECT RESISTANCE, ANIMAL TOXICITY AND
ENDOPHYTE-INFECTED GRASS
D.L. GAYNOR and D.D. ROWANview more
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(115 KB)
Some effects of lolium endophyte (Acremonium lolioe) on sheep production were evaluated using pure swards of high (SO%>) and low (< 5%) endophyte Nui and Ariki ryegrass. The proportion of infected tillers in high endophyte treatments increased by 19% in 15 months. Ryegrass staggers occurred on both high endophyte ryegrasses - being slightly worse on Nui. The peak ryegrass staggers outbreak did not coincide with peak endophyte mycelium concentration in ryegrass plants. Hoggets grazing the low endophyte ryegrasses had a 1.6 kg advantage in liveweight gain in spring, when allowances were equal, but fewer sheep grazing days. In summer and autumn sward damage by Argentine stem weevil, drought and over-grazing eliminated low endophyte Ariki treatments and reduced herbage production from low Nui to 70% of high endophyte Nui. Tiller densities in low endophyte treatments were 28% of those in high endophyte treatments. High endophyte Ariki had the highest overall production: 7.8 t/ha of herbage and 15 kg/head liveweight gain compared with 6.9 t/ha and 12.5 kg/head for high endophyte Nui and 4.7 t/ha and 9 kg/head for low endophyte Nui. Differences in production due to endophyte highlight the need for caution in interpreting results from trials when endophyte status of ryegrass is unknown. Keywords: Lolium endophyte, Acremonium loliae, ryegrass staggers, Lol~m perenne, live weight gain, pasture production, Ariki, Nui
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(291 KB)Pasture dry matter (DM) estimates are used by dairy farmers and their advisers for feed planmng principally during April to September. The three primary estimates required are: average farm cover, pre-grazing herbage on offer, and post-grazing residue. Average farm cover can be approximated by averaging paddocks with the highest and lowest DM. Various ‘short-cut’ methods (pasture height, weighted disc, pasture ‘probe’) were evaluated during 1984 and have provided calibration equations for ‘feed budgeting’ of pre-calving feed. Such equations could be used for day-to-day feeding calculations during autumn to spring provided their limitabons are recognised.
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(68 KB)Agroforests and woodlots offer Northland hill country farmers investment and diversification opportunities. Agroforests have less effect on the ”whole farm” financial position than woodlots, especially where a progressive planting regime is adopted and where no further borrowing is required. Establishment and tending costs for agro-forests are lower, and returns come much sooner. The proven opportunity for continued grazing under trees established in this manner, apart from a short post-planting period, further enhances the agroforesty option. Even where there is reluctance on a farmer’s part to plant trees on high fertility land, the expected financial returns from agroforests on low and medium fertility land will increase the overall long-term profitability and flexibility of the whole farming operation. Woodlots may be more appropriate on low fertility areas where weed reversion is likely. Joint ventures may be worth considering where farm finances are a limited factor. Keywords: On-farm forestry development, Northland hill country, agroforestry, woodlots, diversification, joint ventures, progressive planting regimes, grazing availability.
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(68 KB)The roles of inoculation, pelleting and fertiliser were examined when white clover was oversown into recently cleared North Island hill country with a low resident white clover rhizobia population. Inoculation aided establishment at some sites. Recovery of inoculant strain from plants and soil was generally low, initial nodulation by the inoculant strain being replaced by expanding resident rhizobial populations. Pelleting was necessary to ensure inoculant survival on seed and inoculant establishment. Fertiliser application at oversowing consistently increased seedling and later plant size. Grazing managements (pre and post-oversowing), treading and chemical sward suppression effects were assessed on paddock scale oversowings of white clover into unimproved hill pastures. Pre-oversowing grazing to 900 kg DM/ha or less, and frequent post-oversowing grazings, were necessary to control competition from the resident sward. The use of paraquat: diquat at a low rate was required to maximise establishment. Reducing the water rate with herbicide from 200 to 60 litres/ha maintained high establishment on steep slopes and attained 80% of potential on easy slopes. Additional treading was a practical method of increasing establishment. Keywords: White clover, Trifolium repens, oversowing, establishment, rhizobia, competition, fertiliser, inoculation, pelleting, paraquat, diquat, treading, hill country.
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(148 KB)The Agricultural Machinery Research Centre, Massey University, undertook pasture renovation with a prototype direct drill at several North Island sites. Banded herbicide application was found to provide an effective medium term (two years) means of introducing ryegrass and clover species into browntop dominant pastures being intensively grazed. Specialist pasture species were introduced into Northland dairy pastures by band spraying and direct drilling. Wana cocksfoot and Pawera red clover were slower to establish than Nui and Ellett ryegrass. All species contributed to greater herbage dry matter production of the sward than the control and appeared to be persisting competitively. Keywords: Direct drilling, overdrilling, band spraying, winged opener, inverted T slot, pasture renewal, pasture renovation, prototype direct drill, Northland, Taranaki, Manawatu, no-tillage.
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(93 KB)At this stage the new grass paddocks are providing more grass after three years than other equivalent paddocks on the farm. The benefit will, I hope, continue for longer than this. At this stage I will continue to renovate two paddocks each year as finance permits. The basic seed mix will continue to be Ellett ryegrass and Pitau white clover but I will try other species such as Pawera red clover which I wanted to use this last autumn but no seed was available. In the district generally I have noted an interest in pasture renovation over the last two seasons and I can see that the Dairy Board will continue to be embarassed with the increase in production from the Northland area.
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(46 KB)Nine subterranean clover cultivars and 10 white clover varieties, differing in characters such as morphology and flowering date (sub clover), or growth habit and seeding ability (white clover), where evaluated for persistence and production at 8 summer-dry hill country sites. Results for the first 3-4 years suggest the sub clovers on the New Zealand Acceptable Herbage Cultivars List (Mt Barker, Tallarook, Woogenellup, Glare) should be revised. Regeneration of Woogenellup and Glare was consistently poor, while Tallarook performed well at most sites. The current unavailability of Tallarook seed means Mt Barker is the only effechve option for grasslands in most of New Zealand. Cultivars of the sub clover subspecies yanmnicum (Larisa, Trikkala) showed promise for winter~wet, summer dry environments, as did Nangeela in winter-cold environments. A late-flowering, prostrate, low oestrogenic sub clover similar to Tallarook would be well suited to large areas of summer-dry hill country. There is a clear need for a white clover cultivar adapted to summer-dry hill country as none of the varieties tested survived severe moisture stress at 2 sites (Hawke’s Bay, North Canterbury), and none performed consistently well at the other sites. New Zealand vaneties (Hula, Pitau, G18 and a hill country selection) showed best persistence and production. The overseas cultivars Haifa, Tamar, Louisiana and Clarence Valley, which are all adapted to dry conditions in their country of origin, were consistently poor. Firm selection criteria for dry hill country were not identified, though stolen density and seeding ability should be incorporated and the strong influence of management and soil fertility on genotype performance must be recognised. Keywords: subterranean clover (Trifolium subterraneum L.), white clover (Trifolium repens L.), hill country, dryland, cultivars, persistence, genotype-environmental interaction.
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(119 KB)The growth in horticultural and some industrial development in selected areas of Northland has led to a need for more specific and careful planning and control of limited resources in a number of major catchments. The potential irrigation demands for horhculture comprise over 60% of Northland’s potential water requirements. By contrast, farm water supply needs are only 11% of these needs. Because of their importance to the Northland economy, and in the legislation these needs are given a high priority in water resource management planning. Land uses, including pastoral farming, require careful operation to reduce diffuse sources of pollution.
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(152 KB)Changes in management practices will automatically alter the equilibrium between organisms making up the pasture ecosystem with results not necessarily beneficial to the economic production of the system. Indications of these interactions were observed and monitored in pasture management pasture species trials at Palmerston North. Grass grub attack developed more rapidly, and populations reached higher levels under rotational grazing than set stocking. Porina caterpillar populations tended to show the reverse with higher populations under set stocking than rotational grazing. Earthworm populations were higher under set stocking with a greater proportion of burrowing types, compared to rotational grazing which favoured more of the surface feeding species. These changes are discussed in terms of differences in pasture structure and defoliation patterns affecting microclimate and food supplies for the survival of these organisms. Keywords: Pasture management, rotational grazing, set stocktng, grass grub, porina, earthworms, pasture structure, pasture biomass.
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(96 KB)Herbage production of several ryegrass cultivars was measured over two years at Wairakei and Rukuhia, under conditions of either Argentine stem weevil infestation or insecticide protection. Argentine stem weevil infestations Were similar at both sites and were negatively correlated with incidence of Acremonium loliae infection in ryegrass host plants. Ryegrass yields and tiller densities during periods of larval infestation in spring and summer were greatly increased by insecticide applications at Rukuhia but not at Wairakei. The weak nature of yield responses at Wairakei, despite high larval numbers, appeared related to drought conditions. Plant persistence was improved at Wairakei by these insecticide applications. Surveys of commercial sowings confirmed the correlations between incidence of Acremonium and Argentine stem weevil numbers and damage over a range of solI and management conditions. Between farm differences occurred, however, in the level of tiller damage These results are discussed in relation to strategies for control of Argentine stem weevll uhlising resistant ryegrass cultivars and insecticides. Keywords: Argentine stem weevil, Listronotus bonariensis, lollurn endophyte, ryegrass, tiller survival, drought, control strategies.
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(343 KB)Subdivision is one of the widest used and least researched inputs on livestock farms in New Zealand. Benefits accruing from subdivision in the pasture development stages can be high, however once pastures are developed gams from additional levels may be small. Costs of subdivision have been calculated and are influenced by the size of the property, the number of paddocks and the type of fencing chosen. Keywords: subdivision, pasture development, fencing costs
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(56 KB)Dry summer conditions in Northland have been cited as a significant limiting factor for high levels of milkfat production. For example: “Droughts of significant economic impact on the agricultural economy occur on average once in every three years” (Male 1978). “Dairy farming is a major part of Northland agriculture but the climate is not very suitable for dairy production . and droughts from January/February to April are not uncommon” (M.A.F. 1980). At other times though, Northland has been described quite differently, du Faur (1962) wrote: “Some districts such as South Auckland, parts of the Waikato, Manawatu, Wairarapa ___ will benefit from the provision of (summer) supplementary feed in a majority of seasons. Other areas such as Bay of Plenty, North Auckland . rarely need summer supplementary feeding”. So it woud seem that Northland has a real Jekyll and Hyde character. Despite the different views, over 2000 farmers find dairy farming to be the most economic land use. Northland produces around 13% of New Zealand’s annual dairy export earnings. It is in fact, a larger dairy production area than either the Bay of Plenty, Manawatu/- Wairarapa or the South Island. Today the industry in Northland is stronger than ever. This paper examines the “summer drought” view of Northland by comparing production trends with the South Auckland (Waikato) region - the “Mecca” of New Zealand’s dairy industry.
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(77 KB)The growth end st~rv~val of ryegrass plants Introduced 111 autumn/winter into dairy pasture contammg paspalum, were momtared in a series of field experiments from 1978 until 1982. In each expermwnt plant losses were highest (30-40X of total) in the summer iollowmg their mtroductlon resultmg in only small short term improvements (<500 kg DM/ha) in seasonal productIon About 208 of total losses were directly related to damage caused by cow grazing (severe yrazing,“pulllng”, dung and wine deposition, trampling). The mechamsms accountmy ior the other 80% were less easy to quantify but apparently Involved factors llke competition for light, water and nutrients, climatic stresses and subtle ammal damage to plant growth pomts, leaves and roots. Large plants (20-30) tillers had a higher probablllty of survwny summer than did small plants :< 10 tillers) A number of modifymg factors were used in an attempt to Improve the size and therefore survwal of introduced ryegrass plants. These mcluded additions of mtrogen fertiliser m late winter/spring, Irrigation during summer/autumn and contmuous severe clipping of resident herbage surroundmg introduced ryegrass plants. Only the clipping treatment sigmficantly improduced ryegrass survival. A short (14 d) grazing interval over summer was also detrimental to ryegrass survival, compared to a long interval (28 d). The presence of summer growing paspalum as the main resident competitor reduced ryegrass survival compared to other resident species, and the effect was most noticeable if the plants were further stressed by grazing at a short interval over summer. Practical methods 01 reducmg competitlon between established species and establishing ryegrass seedlings are discussed. Keywords: pasture renovation, ryegrass persistence, ryegrass survival, Paspolum dilatotum, Lolium pewnne, seasonal pasture production, grazing damage, competition control, nitrogen, irrigation, grazing interval.
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(151 KB)A survey was made of 64 dairy herds, grazing pastures containing naturalised tall fescue in the North Auckland peninsula, to demonstrate an assooation of endophyte fungus in tall fescue with IBH. Of these, 40 farms had cattle with IBH and 24 had no IBH. Endophyte fungus was identtfied in tall fescue samples from all survey farms. Acremonium coenophiolum was demonstrated in samples from almost all farms and a high proportion of these also showed a Phiafophora-like endophyte. No correlation could be shown between the presence of endophyte or any farm management practices such as topdressing etc and IBH. Breed susceptibility was observed in Friesian breeds whilst Jersey cattle were less susceptible. IBH first appeared in November and December with a peak m January. Most affected herds had a hlstory of IBH for many years. Keywords: Dairy cattle, tall fescue toxicity, endophyte fungus, idiopathic bovine hyperthermia, IBH. heat-stress, hyperthermia.
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(116 KB)Percentage germination and germination rate (days to 75% germination) of 14 ‘Grasslands’ cultivars from 9 grass species were assessed at constant temperatures of 5,10,15,20,25,3O”C and a fluctuating temperature of S/lO”C. Ryegrass germination did not differ significantly within the range of temperatures used. Germination of Kahu timothy and Maru phalaris was reduced at or below 10°C and at 30°C. Raki paspalum failed to germinate below 15°C. The germination of Apanui and Wana cocksfoot and Matua prairie grass was reduced at 30°C. Germination rates for all species slowed as temperature moved away from the optimum, as did the number of days to the start of germination. Germination rate was greatest for the ryegrasses at all temperatures; for all other species the order was timothy, tall fescue> phalaris prairie grass and cocksfoot at lO”C, and timothy > phalaris, prairie grass>cocksfoot >tall fescue at 5°C. The implications of these results for pasture establishment are discussed. Keywords: germination, germination rate, temperature, temperate grasses, pasture establishment.
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(139 KB)Wild Tall Fescue can be eliminated from Northland dairy pastures. In this paper the principles and methods for eliminating wild tall fescue are discussed. These are based on observations made to US by dairy farmers, farm adtisors and earlier experiences described in farmtng publications. Emphasis is placed on a methodical approach, preparation and having an intensive follow-up programme. Reasons for failure of control programmes are discussed. Keywords: Wild Tall Fescue, elimination of, cultlvatlon, mowing, herbicides, seed viability, re-Infestation.
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(52 KB)Black beetle (Heteronychus arator) and black field cricket (Teleogryllus commodus) may attack pastures in Northland, particularly in dry years. No appreciable pasture production responses to controlling black beetle with insecticides have been measured. In contrast, significant production increases have been obtained from controlling crickets. Crickets can be readily assessed using a simple flushing technique. Effective and economx control can be achieved using maldison grain baits. Drought or black beetle have been wrongly blamed for cricket damage. It is therefore important to correctly identify pest problems so that control measures can be successfully carried out. Keywords: black beetle, black field cricket, damage, control.
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(123 KB)The association between subdivision and other management resource inputs and levels of hill country sheep productive performance are reported in this paper. An analysis of computer simulated grazing systems and practices adopted by a sample of thirty farmers in North-East Wairarapa indicates that high levels of production were achieved with variable levels of subdivision. Appropriate grazing systems were often limited by poor planning and implementation rather than inadequate permanent fencing. Although subdivision was associated with higher autumn sheep liveweights on the survey farms, similar or larger increases could be achieved by refinmg existing management systems. Further increases in subdivision therefore may not lead to increases in productivity on many hill country farms. Keywords: Subdivision, hill country, management, computer simulation, survey, grazing systems.
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(80 KB)A simple version of the model validated by Bricham et of (1985) was used to illustrate the factors affecting average daily intake of animals under different grazing conditions. The model accounts for differences in pre-grazing pasture mass and grazing pressure in describing pasture disappearance through time under grazing. Analyses based on the model showed the interdependencies between intake and pre-and post-grazing pasture mass and grazing pressure. In ewes grazing to a common residual (400 kg GDM/ha) intake varied between 1.32 and 0.75 kg GDM/h/day where pre-graze mass varied between 2500 and 1000 kg GDM/ha. It was concluded that where the objective of grazing management is to control animal intake at any level, attention must be paid to pre-grazing pasture mass in setting target residuals. Appropriate residuals and grazing pressures to achieve target intakes can readily be assessed for any pre-graze mass using the model presented. Keywords: Pasture mass, animal intake, pre-graze mass, residual, grazing pressure, stocking density, model, feed budget.
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(111 KB)The MAF Fertiliser Advisory Service provides fertiliser and lime recommendations for pastures, lucerne and cereal crops. It does this by combining farm details with an understanding of the behaviour of nutrients in soils, plants and animals derived from many years of soil fertility research. Recommendations are for individual farms or blocks of land. Balance models are used in which fertiliser requirements are calculated to replace nutrients lost from cycling pools via animals and within the soil. Soil tests assess the influence of previously applied fertilisers and are used to modify recommendations. A technical report showingfertiliser options is prepared for advisers while short and long term recommendations are given in a more basic report addressed to the farmer. Keywords: Fertiliser recommendations, soil testing, pastures, cereals, lucerne.
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(81 KB)Considerable effort is expended measuring pasture parameters that relate to animal perform mance. Traditionally farmers have used visual impact and experience as their method of pasture assessment to make management decisions. The simplest measurement collected by researchers, pasture height, is developed to the point where it can be used as a guide to predict pasture mass and animal performance. This paper presents relationships between height and mass for improved pastures in summer dry North Island hill country. A pasture 5cm tall will give hogget growth of 60 gjday in summer, 90 in autumn, 100 in winter and 200 in spring. Similarly 5cm will be 2250 kg DM/ha in summer, 1900 in autumn, 1520 in winter, 1640 in spring and 2200 in late spring. Keywords: Height, mass, predictor, grazing, quality, animal performance, feed levels, parameters, pasture.
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