Between 1970 and 1991,53 ha of Pinus radiata plantations were established and managed in an agroforestry system on a 245 ha farm at Roydon Downs in the eastern Bay of Plenty. Plantations on a further 30 haareplanned. This paperoutlines the experience gained, and uses recently developed agroforestry modelling systems to evaluate the current and projected physical yields, cash flow and profitability of several agroforestry options when applied to a typical Bay of Plenty sheep and beef farm, The increasing availability of genetically improved tree stocks, together with developments in silvicultural techniques, have resulted in a low cost, easily managed tree crop, using mainly family labour. The objective is to produce high quality domestic or export sawlogs and peeler logs. Planting the least productive third of the farm is predicted to more than double the total farm surplus. For farming to provide an equivalent economic return from the same land, gross margins would have to increase from $29 to $60/livestock unit (LSU). or livestock carrying capacity would have to increase from 8 to 16 LSU/ha. Options involving 135 stems/ha and 225 stems/ha gave a similar economic return. However, concerns about the quality of the final product indicate that cash flow constraints should be met by varying the size and rate of planting, rather than by reducing final crop stocking. A method of financing initial costs based on sharing final revenues with investors is presented. Keywords agroforestry, Pinus radiata, estate model, profitability
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(246 KB)An analysis of 10 years’ production records of a group of farms indicated that for all the improved management techniques employed, production had not increased. Kilograms of milkfat per hectare did notgiveameasureofresourceuseorthemanagement ability of the farmer. Farmers were surveyed. The following data were collected for the years 1978/79 to 1987/88: Keywords index, management performance, goal, objective.
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(59 KB)Facial eczema (FE) is a disease of grazing ruminants caused by ingesting spores of the fungus Pithomyces chartarum. The spores contain a toxic compound, sporidesmin, which causes liver injury, sensitivity to sunlight and reduced performance in susceptible dairy cattle. The extent of production losses is summarised. Research at Ruakura has demonstrated that the resistance of animals to FE is inherited, with a heritability estimate of 0.31 in dairy cattle. Genetic progress in dairy cattle could bc achieved by progeny testing young bulls, and selecting for use as sires those with the most resistant progeny. However, work over the last decade in sheep at Ruakura has demonstrated the success of selection based on performance testing (i.e. dosing potential sires themselves and using those that are most resistant to the challenge). In January 1990 we began to develop a performance test for use in the preliminary screening of young dairy bulls for FE resistance. The details of these tests are described. Keywords facial eczema, dairy cattle, performance testing, production loss
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(80 KB)Recent results from field trials comparing the agronomic effectiveness of water soluble fertilisers (single superphosphate (SSP), triple superphosphate (TSP)) and fertilisers of low water solubility (‘slow release’, reactivephosphaterock (RPR) fertilisers) are reviewed. It is shown that the pasture production data from the ‘National Series’ of trials are consistent with, and can be described by, a model for the dissolution of RPR in soil. Applying both the pasture production data and the dissolution model the term ‘lag time’ associated with ‘slow release’ RPR is defined and quantified for New Zealand conditions. Results show that on average the rate of release of P from RPR is about 30% within the year of application, 23% in year 2 and progressively less in subsequent years. It follows that when RPR is applied annually, the amount of Preleased annually, from the current application and from the residues of previous annual applications, is 30,53,70,82, 9 1,96% as a fraction of the total P applied annually. Consequently about 3.5 times the amount of RPRP is required to achieve the same yield as soluble P in year 1, about 2 times in year 2 and 1.5 in year 3. The lag time is defined as the time required to accumulate sufficient RPR residues in the soil from applications such that the annual amount of P dissolved from RPR each year is equal to or greater than 90% of the amount of total RPR-P applied annually. The lag time associated with RPR use is about 4-6 years depending on the site. The agronomic performance of RPR based on the National Series data was not associated with soil pH (5.1 to 6.3), annual rainfall (700 to 1800 mm) or soil phosphate retention (13-98%). This probably reflects the narrow range and confounding effects of the soil and climate factors. The experimental basis for the current soil pH and rainfall boundary conditions are briefly discussed. Available evidence suggests that the P dissolved from RPR has the same agronomic effectiveness as P from soluble fertiliscrs. The agronomic implications of these results on P fertilisers of intermediate solubility (i.e. PAPR and Longlife) are discussed in relation to field results. Keywords agronomy, comparison, dissolution, fertilisers, Longlife, PAPR,phosphorus, RPR, slow release, soluble P, single superphosphate, triple superphosphate
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(227 KB)This paper compares a herbal ley (of particular interest to farmers involved in the ‘organic’ branch of agriculture) with a conventional pasture (ryegrass-white clover) and a more intensive system (pure ryegrass receiving 400 kg fertiliser N/ha/yr) in a study lasting 2 years. The herbal ley seeds mixture was prepared following the pioneering ideas of Robert Elliot in his “Clifton ~~ ~~~~~Park”mixture,-whichbasically-included~a-group of ‘non-aggressive’ grasses, forage legumes and herbs. Pasture production (average of 2 years) from Herbal ley was 15 t DM/ha/yr, representing approximately 90% of the yield from the intensively managed pure ryegrass pasture receiving 400 kg N/ ha&r and some 2530% more than from ryegrassclover. A major feature of the herbal ley was substantialproductionduringlate.springandsummer, when chicory (the most dominant herb), and red clover and white clover made a major contribution to herbage yield. In winter the total yield was similar tothatI?omthegrass-cloverpasture.L.egumecontent was 23 and 3 1% (averaged over the year) for Grassclover and Herbal ley pastures respectively. In spite of this difference, symbiotic N fixation was similar. So fixation efficiency on a legume yield basis was 50.3 and 3 1.6 kg N fixed/t legume DM harvested, respectively. These results could reflect a different pattern of utilisation of soil N, as a consequence of the different botanical composition of the swards. In summary, the performance of the herbal ley offers the promise of an alternative, ‘specialist’ pasture and would be highly beneficial if quality feed is required in summer. Keywords herbal ley, biological fertility, nitrogen, symbiotic nitrogen fixation, pasture mixtures
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(184 KB)Establishment of grasses and legumes drilled in spring with a prototype strip seeder drill or a conventional tripledisc drill werecomparedon two sites in the presence and absence of paraquat. On theE%rnscleughsite,plantestablishmentinautumn, as a percentage of viable seed sown, was higher with the prototype drill than with the triple disc drill in the absence of paraquat. The application of paraquat increased establishment with the triple disc drill and differences between the drills were not consistent over species. Paraquat had no discernible effect on the competing vegetation or establishment at Ohau Downs. Establishment of birdsfoot trefoil, cocksfoot and tall fescue, but not alsike clover, was significantly higher in autumn in the prototype drill treatment. Treatment effects on standing herbage mass on both sites followed a similar trend to establishment although paraquat increased herbage mass in the prototype drill treatments on Eamscleugh, in contrast to the nonsignificant effect on establishment. The present results indicate the potential of the prototype strip seeder drill for cost effective establishment of improved pasture species in difficult environments. Keywords direct drilling, establishment, strip seeder, luceme, tall fescue, birdsfoot trefoil, upland brome,alsike clover,cocksfoot,paraquat, herbicide
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(85 KB)Changes in soil mineral nitrogen(N) were monitored during regrowth of pasture between consecutive grazings in two contrasting grassland systems; Grass-clover (the norm in NZ) and a more intensive system, Grass+N400 (pure grass + 400 kg fertiliser N/ha/year). The experiment was carried out during autumn at DSIR Grasslands.Palmerston North. Net mineralisation of N under field conditions was estimate_d- i~n- an ancillary experiment, using soil samples from undisturbed soil cores contained in PVC tubes. The dynamics of mineral N in soil were dominated by a ‘pulse’ of ammonium, observable soon after grazing. Nitrification proceeded rapidly thereafter. Mineral N in soil then progressively declined, much of it going into organic combination presumably through uptake by plants. Since nitrate formation in the soil is minimised by maximising the residence time of N in plant (organic) form, differentmanagementoptions(varyinginfrequency and intensity of defoliation) may have important influences, not only on pasture utilisation and production, but also on the management of mineral N in the soil-plant-animal complex. Tubes embedded in soil and incubated in the field have provided some additional, useful perspectives. There was only limitedevidence for significant net mineralisation of organic N throughout the period of regrowth. Analyses of individual soil cores demonstrated a sharp contrast between the pasture at large and the 10 - 15% of total area influenced by urine from the previous grazing, in terms of mineral N content. ‘Averaging’ these by bulking numerous cores into a composite sample can provide an accurate quantitative estimate of mineral N, which can be related to herbage uptake of N over the whole area. But if losses of N (by leaching or volatilisation) are disproportionate to the concentration of mineral N in affected and unaffected volumes of soil, then bulking samples and averaging will not be the most appropriate way to estimate these losses. The results of this study point to the importance of the urine of grazing ruminants as a N substrate for pasture regrowth in the absence of fertiliser N. At the same time, urine patches provide the main avenue for Nescape to the wider environment from developed pastures. Keywords mineral N, N in pastures, N cycling by animals
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(167 KB)Plugs of sheep-grazed, ryegrass-dominant pasture were transplanted to a glasshouse, in order to make detailed studies of tiller appearance from the base of flowering tillers in late spring-early summer. In 2 experiments, cutting treatments which reduced the opportunity for transport of assimilate from parent flowering tillers to daughter tillers markedly reduced both numbers of daughter tillers formed and their size. In one of the studies, proportion of radioactive carbon dioxide fed to flowering tillers, but recovered from daughter tillers, was 7.0%, and this transported radiocarbon appeared to be delivered preferentially to leaf elongation zones of young tillers. There appear to be fundamental differences in tillerbehaviour between ‘Grasslands Ruanui’ ryegrass and ‘Ellett’ ryegrass. The implications for farm practice are briefly discussed. Keywords ryegrass, tiller dynamics, radiocarbon, summer pasture production, pasture persistence
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(108 KB)An integrated management system involving cattle, ewes and lambs developed to minimise levels of parasitic nematode contamination of pasture was evaluated in a 2-year (1989-1991) study. Four experimental farmlets were managed as self-containcd units over a May-May year. Over the two years, stocking rate averaged 15 su/ha and cattle:sheep ratio 35:65. Three treatments (lambs regularly drenched, ewes drenched post-lambing/ lambs undrenchedand undrenchedewes andlambs) were similarly managed (set-stocked, lambing to weaning, 7-day shifts post-weaning, a 77-day interval between consecutive lamb grazings and a strict rotation of lambs followed by ewes with cattle midway between the ewe and subsequent lamb grazing). A fourth treatment differed in each year: in year 1, lambs were set stocked over summer and in year 2 cattle followed lambs, and ewes were positioned mid-way in the rotation between lambs and cattle, In both years, the management system developed to minimise nematode parasitism in lambs mamtained low levels of infective larvae on pasture (~80 L3 larvae/kg pasture), and a faecal egg count in lambs of less than 1500 epg; clinical parasitism was not observed. However, regular anthelmintic drenching of lambs significantly (P~0.01) increased liveweight gain of lambs from weaning in November to May by an average 35% over the 2 years. In year two, grazing ewes ahead of lambs significantly increased (PcO.01) pasture larvae levels and lamb faecal egg counts and decreased liveweight gain compared with grazing cattle ahead. Drenching ewes to minimise effects of the post-parturient rise in faecal egg count had no influence on nematode levels in lambs or on lamb performance. Keywords parasitic nematodes, grazing management, lamb growth
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(123 KB)Arad reactive phosphate rock (RPR) and single superphosphate(SSP) were compared as phosphate fertilisers in a sheep farmlet grazing trial and in two mowing trials over 3 years. The trials were on a volcanic ash soil at the MAF Te Kuiti Research Area on a site with limited fertiliser addition in the previous 2 years (Olsen P soil test averaged 10 in the grazing trial). Soil sulphur levels were high and there was no requirement for added sulphur over the -3 years of the trial. Pasture and animal measurements showed responses to SSP in all years, with RPR being initially less effective than SSP. By year 3, responses from RPR were near those from SSP. Economicassessmentof thegrazing trial corresponded with production data, except in year 1 when there was little benefit from either fertiliser. SSP was more cost-effective than RPR in year2 whereas they were similarin year 3. Over the 3 years, both fertilisers were profitable and there was an apparent cumulative net benefit from SSP over RPR. It was estimated that by year 4 the cumulative net benefit would be similar for both fertilisers or would be reversed in favour of RPR. Keywords reactive phosphate rock, hill country, grazing trial, superphosphate, mowing trials
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(124 KB)Seasonal and annual DM production of direct drilled dryland species ‘Grasslands Maru’ phalaris (Phalaris aquatica L.) and ‘Grasslands Roa’ tall fescue (Festucuurundinuceu Schreb.) and perennial ryegrass (Loliumperenne L.) cultivars ‘Grasslands Pacific’, ‘Droughtmaster’ and ‘Yatsyn-1’ was compared with that of established pasture in an environment prone to summer dry spells. Two methods of establishment using only Yatsyn-1 were examined: either the elimination of existing pasture with glyphosate and drilling, or drilling without spraying (undersowing). Average annual DM production (over 3 years) of Yatsyn-1 drilled into pasture previously sprayed with glyphosate was 12% more productive than established pasture. Maru phalaris, Droughtmaster and Pacific had similar annual DM production to established pasture, and Roa tall fescue produced 25% less. Yatsyn-1 undersown intopastures without previous spraying with glyphosate produced 9% less than Y atsyn- 1 established by the spray and drill technique. Phalaris established well but after 3 years the content of phalaris had declined markedly, suggesting poor persistency. Tall fescue was slow establishing but had good persistency, as did all ryegrass cultivars. Yatsyn-1 direct drilled into pastures eliminated with glyphosate before drilling is recommended for an environment prone to summer dryness to increase annual DM production. Keywords pasture production,established pasture, ryegrass cultivars, phalaris, tall fescue, establishment techniques, summer droughts
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(129 KB)Four white clover (Trifolium repens L.) cultivars, 4 pre-release cultivars and 24 breeding lines were evaluated in small plots in mixed species swards under rotational cattle and sheep grazing for 2 years. There was no significant stock class x line interaction for proportion of clover in the sward. There was no evidence that medium- and smallleaved types yielded better under sheep grazing while larger-leaved types yielded better under cattle grazing. Lines with the highest clover content tended to be large leaved and upright irrespective of stock class. They also had moderate to high stolon growing point densities. Breeding programmes have developed lines with high stolon growing point densities, ensuring vegetative persistence, while still maintaining a high proportion of clover in the sward. These pre-release cultivars and breeding lines gave significantly better clover contents than existing cultivars. Keywords cultivars, selections, plant habit, cyanogenesis, stolon growing point density, clover content, cattle grazing, sheep grazing
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(116 KB)The fungal endophyte Acremonium lolii, in association with its ryegrass host, produces both peramine, a feeding deterrent to Argentine stem weevil,andlolitrem B,a neurotoxin causing ryegrass staggers. Endophyte strains vary in the ratio of production of these alkaloids in the ryegrass. In field evaluations of several endophyte/ryegrass - combinations, ‘Endosafe’, a zero lolitrem B, high peramine strain protected its host against Argentine stem weevil attack and did not cause ryegrass staggers in lambs grazing three of four ryegrass cultivars. Lambs on the endophyte-free and Endosafe combinations had the highest liveweight gains and while endophyte-free ryegrass did not cause ryegrass staggers it suffered significant stem weevil damage. Ryegrasses with their ‘wild-type’ endophyte and a high lolitrem B strain ‘Waiau’, had only minor stem weevil damage but caused severe ryegrass staggers and weight loss in lambs. Ryegrass with the no lolitrem B, low peramine strain, ‘IOOA’, suffered some stem weevil damage and although not causing ryegrass staggers, did cause weight loss in lambs. Ryegrass/endophyte metabolites in addition to lolitrem B may have affected animal performance on endophyte-infected ryegrass. Keywords endophytc, Endosafe, perennial ryegrass,ryegrass staggers, Argentine stem weevil, liveweight gains, peramine, lolitrem B
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(128 KB)Deferred grazing is the practice of holding over pasture in situ that has been considered surplus to animal requirements in spring, to be grazed at a later date when a shortage of pasture occurs, usually in summer/autumn. This non-mechanical method of pasture conservation was developedandpractised from 1986-1989 at the Taranaki Agricultural Research Station as part of a low cost dairy system. At the low stocking rate (3.7 cows/ha) 13% of the farm area was conserved as deferred grazing and allowed to naturally reseed before grazing. The reseeding doubled the tiller density of perennial ryegrass, increasing pasture growth by 15 19% the following season. This, combined with the nil cost associated with conserving supplements, made this system more profitable than the traditional haysilage system. For the natural reseeding to be successful, the deferred grazed pasture should be removed from thegrazingrotationduringtheryegrassreproductive phase (mid-October to mid-November) and not grazed until after the ryegrass seed is mature (mid- January). The method developed to Wise deferred grazed pasture has been to strip graze between the morning and night milkings. Cows are offered a pasture allowance of 10 kg DM/cow/day or one, two hundred and fiftieth of the farm per day, to achieve a utilisation of around 50%. Cows graze selectively leavingaresidualofabout4000kg DM/ haofpredominantly dead material. Mowing before grazing increased utilisation, but there was no advantage in milk solids production. No benefits were observed when tall fescue or phalaris pastures were allowed to naturally reseed. Deferred grazing had no effect on grass grub or porina populations if grazed before April. No detrimental animal health effects have been measured with deferred grazing. To reduce farm operating costs and increase pasture growth, it is recommended that 10% of the farm is deferred and allowed to naturally reseed on an annual basis. Keywords deferred grazing, pasture conservation, naturalreseeding, tiller density,pasture growth, dairy production
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(98 KB)A Fertiliser index is described which consists of summing total superphosphate applied to a site after using an annual discount to past applications. This index is related to relative pasture yield for 3 major New Zealand super-phosphate withholding trials using a Mitscherlich function. A discount factor of 0.15 was chosen. Accuracy of relative pasture yield prediction was at least as good as for an Olsen P predictor and better where sulphur responses were implicated in the response to super-phosphate (r-$0.77 to 0.93). The effect on relative pasture yield predictions of measurement errors in Olsen P and Fertiliser index were similar using the Whatawhata site for comparison. A 20% error in predictor resulted in a 3 unit error in relative pasture yield estimation. Measurement errors in the Fertiliser index are minimal if the last 10 years’ fertiliser history are known. Where this knowledge is not available, 5 years of known fertiliser history and use of national average fertiliser statistics beyond that may give acceptable estimates of relative yield. The advantage of the model for onfarm use is that intended fertiliser use directly affects the index and hence prediction of relative pasture yield. This facilitates economic analysis of options. An analysis using the model to investigate production consequences of fertiliser use at the industrylevelshowscontinuationofcurrentfertiliser levels on hill country farms will result in a drop in farm output of 13% in the next 10 years. Keywords super-phosphate, discount, Olsen P, policy, regional production, pasture yield, fertiliser strategy
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(118 KB)Capital fertiliser dressings and intensified grazing management (to fully utilise available pasture) are shown to be essential components of hill country pasture improvement options when they were analysed by a computer simulation model. For calculations to be profitable, animal performance needed to exceed specified minima throughout the period of development. For traditional mixed livestock policies, these minima were that finishing cattle reach 300 kg carcass weights and breeding ewes achieve more than 100% lambing. Keywords pasture improvement, gross margin, reseeding
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(97 KB)Group farm monitoring is a team approach to technology transfer involving farmers, consultants and researchers. Biological and financial components of farm production are monitored to provide data for decision making and a knowledge of the farm which is shared among the group.Scientists from the Whatawhata Research Centre (WRC) provide comparative information and relevant technology. Production gains on the monitor farms have been achieved within 3 years and further gains are possible. Group farmers benefit from renewed enthusiasm in farming and an increased interest in new technology. Key success factors are group ownership of decisions and outcomes and the credibility of consultants and scientists who are seen to stand by the technology delivered. MAF Technology consultants initiated farm monitoring in the Northland area and have benefited as have farmers through the WRC contact, which provides a broad spectrum of information from a multi-disciplined research group. Based on the Northland success, group farm monitoring has been accepted as a model for technology transfer throughout New Zealand. Keywords group farm monitoring, information, decision making, technology transfer
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(72 KB)Three large glasshouse experiments were conducted to identify white clover (Trifolium repens L.) genotypes, and develop experimental seed lines, with increased tolerance of low-phosphorus (P) soils. The first compared the P response of 119 white clovercultivars; the second, the P response of 110 white clover genotypes from 11 selected cultivars; and the third the P response of progeny from crosses between genotypes selected for differences in response to added P. There were significant differences among cultivars and genotypes for shoot dry weight response to added P. Evaluation of progeny showed that high P response was dominant over low P response, the general combining abilities of all high P response genotypes were greater than that of the low P response genotypes, and that narrow sense heritabilities for P response were moderate (~0.4). The chances of manipulating differences in P response by breeding, application of the results to dateandfuturedirectionsofthisworkarediscussed. Keywords white clover, Trifolium repens, phosphorus response, low-phosphorus tolerance, heritability, breeding, combining ability
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(190 KB)Low ewe liveweights and general performance on Bay of Plenty sheep farms is a common problem aggravated by farmers keeping lambs through late autumn in an attempt to improve returns. Ewe liveweights of 50 kg or less result in low lambing percentages and wool production of around 4.4 kg/ sheep stock unit. This paper outlines one farmer’s identification of the problem and the introduction of ‘Grasslands Puna’ chicory to help solve this problem. A pure sward was very well established using the spraydrill technique at relatively low cost, despite a late sowing date. Several options now present themselves to increase profitability and flexibility on the property. Keywords chicory, lamb growth, Bay of Plenty
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(44 KB)A prototype strip seeder was developed to establish grasses and legumes in the semi-arid and montane environments of the Mackenzie Basin and Central Otago. Specifications of the strip-seeder required for cost-effective performance were identified on the basis of previous direct drilling investigations in this environment, and included: (a) removal of a strip of existing vegetation to reduce competition; (b) creation of seed bed tilth; (c) controlled and separate placement of seed and fertiliser; and (d) compaction of the drilled seed bed to enhance contact between seed and soil. The prototype strip seeder was built around a modified Duncan 730 multi-seeder chassis, and was used to install spring and autumn trials at Eamscleugh in Central Otago and at Ohau Downs in the Mackenzie Basin. Mechanical improvements were made as the trials progressed. The experience gained, and results from the trials, confirm the suitability of the prototype strip seeder concept for successfully introducing grasses and legumes into this terrain. Keywords direct drilling, strip seeder, seed placement, seed depth, sowing depth
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(70 KB)The Maori land resource in the Bay of Plenty district is variously defined as to area and undefined as to land use. A general resumé of Maoti land title and tenure is given and procedures on succession commented on. Two statutory avenues which may assist utilisation, the establishment of trusts under section 438 of the Maori Affairs Act, and the establishment of Maori Incorporations, are discussed. Lending for development on the security of Maori land was largely the preserve of the now defunct Maori Affairs Department. No commercial organisation has emerged to undertake this role and development of Maori land on any appreciable scale is now likely to cease. Keywords Maori land, legislation, succession, utilisation, mortgages.
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(148 KB)The effects of applying nitrogen (N) fertiliser at 100 kgN/ha as a split application (40 kgN/ha in July/ early August and 60 kgN/ha in October) and of earlier calving (16 July vs 2 August) on milk solids production and farm profitability were evaluated at the Waimate West Demonstration Farm in South Taranaki. Two systems were comparedover 3 years: calving on 2 August with no N (LC) and calving on 16 July with N (ECN). In the second and third year calving on 16 July with no N (EC) was also evaluated. All herds were stocked at 4.0 cows/ ha. Early calving without N (EC) increased the average lactation length/cow by only 2 days because poorer cow condition andless winter supplements required earlier drying off. Milkfat increased by only 13 kg/ha and protein by 1 kg/ha. Early calving with N (ECN) increased the average lactation length/cow by 16 days, milkfat by 57 kg/ha and protein by 27 kg/ha. Nitrogen applied in October was more effective (kg milk solids/kg N) at increasing milk solids production (1.08 kg milk solids/kg N) than N applied in late winter (0.56kg milk solids/kg N). At 4.0 cows/ha and calving on 16 July, the break-even milkfat price for N use was $3.OO/kg fat. Keywords milk solids, production, nitrogen fertiliser, calving date.
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(128 KB)Natural reseeding of 5 grass species was monitored over 2-3 years in summer dry hill country in central Wairarapa and Taupo. Measurements included numbers of seedheads and seedlings appearing, survival andgrowth of tagged seedlings and their contribution to sward tiller populations. Effects of fertiliser (high, low) and summer grazing managements (continuously summer grazed, spelled from grazing during summer) were examined. All seedlings appeared in autumn/early winter. No seedlings of phalaris and few tall fescue and cocksfoot seedlings were found, and all failed to survive the first summer. Reseeding of prairie grass was significant, failure of which corresponded with a general decline in persistence of prairie grass swards. With summer spelling in central Wairarapa, prairie grass had relatively high seedling numbers (144/m?), seedling survival (10%) and contribution (11%) to prairie grass tillers in the sward. Reseeding was most prolific for perennial ryegrass (Nui and resident ryegrass) (283 seedlings appeared/m2). Summer spelling gave high ryegrass seedling numbers in central Wairarapa but lower numbers at Taupo, compared with summer grazing. At both sites, however, summer grazing increasedryegrass seedling survival and seedling contribution to the total sward (11% of total tillers), despite inherently dense, competitive swards. Effects of fertiliser were generally minor. Variation between sites and years was considerable. Reseeding had little effect on numbers of new plants in the sward, but may be significant when considered cumulativley over a number of years. Keywords natural reseeding, summer dry hill country, summer grazing managements, fertiliser, prairie grass, ryegrass, phalaris, cocksfoot, tall fescue
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(198 KB)Nitrogen fertiliser was applied in June 1990 to early-August lambing systems and production was compared with traditional September lambing. Nitrogen (30 kg N/ha) increased pasture growth rates by 3-4 kg DM/ha/day and increased production by 210 kg DM/ha during July-September inclusive, Nitrogen responses were greatest in southfacing paddocks; least on easy contoured paddocks; and did not differ between “resident” pastures and “improved” pastures that had been oversown with new pasture cultivars 5 years before. Compared with traditional September lambing, early-August lambing (plus N) resulted in20% fewer lambs at weaning; 2.4 kg heavier lamb weaning weights; similar ewe weaning weights; and similar bull live weights in January. While N applications to earlier lambing systems reduced the differences in ewe and bull weights previously recorded between the lambing date treatments, it was not a profitable strategy. Assessment of pasture response to N (30 kg N/ha) was repeated in 1991. Nitrogen increased production by 260 kg DM/ha and responses were similar for all paddock and pasture types. Keywords nitrogen fertiliser, early lambing, hill country
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(131 KB)The effect of a pastoral fallow (the ‘spelling’ of a pasture from early spring (September) to autumn (April/May)), with or without added fertiliser, on pasture and legume growth rates, total pasture biomass accumulation, nitrogen fixation, and on soil carbon and nitrogen cycling in the year of the fallow, and in the year after thef allow, wa sevaluated on 55ha of moderate to steep~low fertility, summermoist hill country at Ballantrae, DSIR Grasslands Hill Country Research Station. The major effect was to open the sward, increase individual plant size, vigour and rooting depth, increase the presence and vigour of white clover by creating new niches for growth, and improve N fixation by legumes in the year after the fallow only. The data on soil C and N dynamics are consistent with the concept of fallowing adding a pool of potentially available N to the soil. The benefits of a fallow for moist hill country and other pastoral farming systems are discussed. Keywords pastoral fallow, hill pastures, nitrogen, legume growth
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(153 KB)Ryegrass monocultures and mixtures containing at least one or two other grass species were compared on three sites over 3-6 years. At Atiamuri, under intensive dairying, a tall fescue-cocksfoot pasture yielded 3.7 t/ha/yr, and 14 kg/ha/day in spring and 17 kg in summer, more than the mdnocuiture. Under dairying at Opiki, a phalaris-ryegrass mixture yielded 1.8 t/ha/yr, and 5 kg/ha/day in winter and 7 kg in autumn, more than the monoculture. At Castlepoint Station, a cocksfoot-tall fescue pasture yielded 1.4 t/ha/yr, and 11 kg/ha/day in summer, more than the monoculture. These pastures would more closely meet (or exceed) animal feed demands, so increasing gross farm income through increased animal performance and carrying capacity. Keywords Grasslands Kara cocksfoot, Grasslands Maru phalaris, Grasslands Puna chicory, Grasslands Roa tall fescue, ryegrass monoculture, dry matter yield, animal demand
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(153 KB)Dairy conversion units are as individual as the persons operating them. The need for flexibility in planning is easily demonstrable. Less than 6 months after purchasing a second-year conversion property near Edgecumbe the owners discovered a need to review fully the goals and objectives encompassed in their management plan. Such a move had been “forced” upon them for several reasons, primarily: (i) an announcement that milk solid (fat and protein) returns could be up to 25-30% lower than initially anticipated and (ii) the prompt recognition that pasture performance reflected much greater variation than earlier thought. Short- and medium-term goals were reviewed, resulting ina shift in priority from pasture renovation and increased stocking rate to additional drainage and fertiliser. The confidence to make such changes was provided through a decision-making process classed as “whole-farm technology transfer”. Decisions that affect one component of the dairy production system are not made in isolation from the effects on another. Decision-making on this property is a stepwise, consultative process based on objective rather than subjective means and focuses on the ‘wider vision’ of the property owners. Keywords decision-making. goals and objectives, dairy conversion, whole farm technology transfer, management support
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(83 KB)A 5-year experiment at Ruakura Agricultural Centre measured the effects of blanket application of glyphosate herbicideand direct drilling ofperennial ryegrass and white clover on seasonal pasture composition and production. Plots were sprayed in autumn 1985 with 6,4,2 and 0 l/ha of glyphosate before direct drilling with a mixture of ‘Ellett’ ryegrass and ‘Grasslands Kopu’ white clover. These treatments werecompared with plots of the original paspalum pasture which was not sprayed or drilled. Plots were arranged at random in 6 replicate blocks that were rotationally grazed by dairy cows. Applying high rates (4-6 l/ha) of glyphosate completely eliminated paspalum from the pasture and subsequently, treatment differences between the 6 and 4 l/ha treatments for most variables were small. Differences in winter/spring herbage accumulation between the 4 l/ha treatment and the control plots were highest in the first year and declined with time, representing 1.9,0.8,0.8.0.6 and 0.4 t DM/ha, respectively, over the S years of the trial. The declining growth response was paralleled by an increasing level of paspalum in the previously sprayed plots, which exceeded 30% of DM by the fourth summer. Over the same period, their summer ryegrass contents had declined by more than half (46-20% of DM). These results suggest that for this site further renovation using glyphosate (at 4 l/ha) would be beneficial after 4 years to recapture the immediate superior growth responses, and since the costs of renovation could be met within 2 years. Keywords Paspalum dilitatum, Lolium perenne, seasonal herbage accumulation, renovation methods, glyphosate herbicide, dairy pastures, volunteer paspalum invasion, pasture botanical composition stability
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(484 KB)The attributes of 1800 ryegrass plants removed from North Island hill country aredescribed and the implications for oversowing discussed. Morphology was varied but the mean of the population was prostrate and densely tillered, resulting in dense pastures under intensive grazing. Although morphology was not related to the site of plant origin, agronomic response to low nitrogen and moisture stress was. Plants from north-facing steep areas responded least to application of nitrogen or water indicating a low relative growth rate. A probable survival mechanism for moisture-stressed plants is reduced vegetative growth and increased seed set. Response to moisture stress was found to be heritable. In moderate-high fertility steep sites total ryegrass production has not increased after oversowing new cultivars. It is assumed that this is a reflection of the number of niches available for ryegrass exploitation. Our studies show that the strength of existing ryegrass is its genetic diversity and its ability to exploit the various niches present in hill country. The growth and expansion of these ryegfass populations should be actively encouraged. In niches below the optimum for rycgrass growth new species should be introduced. Keywords hill country, perennial ryegrass, morphology, stress, genetics, oversowing, management
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(108 KB)Patterns of pasture growth were measured on 3 farms in the Bay of Plenty (BOP) and at No2 Dairy (Ruakura Agricultural Centre) in the Waikato from 1989 to 199 1. A standardised trim technique with cages and 4-weekly cutting under grazing was used. Long-term seasonal growth patterns, using a predictive pasture model, were also simulated. Simulated pasture growth from long-term climatic data shows that pasture growth rates are higher in winter, early spring and late autumn in the BOP than the Waikato. However, the actual measurements over the 2 years show that pasture growth over the latter periods is lower at the BOP sites than at the Waikato site. In the BOP the spring peak is much later than in the Waikato while an early summer peak, with higher growth rates than in the Waikato, occurred in the BOP. No such summer peak was evident in the Waikato. The difference between the two regions is caused by the large contribution of subtropical grasses to sward production in summer and autumn, The prolific summer growth of subtropical grasses may explain the low ryegrass content and low pasture production in winter. The lower than expected autumn, winter, spring production may also becaused by low clover content, possibly a result of competition from subtropical grasses and a sulphur deficiency. The apparent low amount of nitrogen fixed by clover may explain the low rates of pasture production over the cooler season. Applications of nitrogen fertiliser may substantially increase dry matter production from April to September. Keywords pasture,simulation,subtropical grasses, Paspalum, Digitaria sanguinalis, growth rates
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(149 KB)The process of setting targets and intensively monitoring performance on an Opotiki dairy farm improved milkfat production over one season by 6% when compared to surrounding farms. By comparing actual results with performance targets a number of constraints to improved milk production were identified. The constraint given highest priorty was the extended calving spread. Management was implemented to overcome this constraint with the result of a mean calving date 19 days earlier. This improvement was the major reason for the 6% production increase. Keywords: Comparative Farm Programme, targets, monitoring, constraints, pasture growth, utilised pasture
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(98 KB)The soil nutrient status of sheep and beef, and dairy farms in the Bay of Plenty region was examined using results from over 4700 soil samples analysed by MAF between 1988 and 1991. The proportion of farms in various soil test categories was determined and related (using known relationships) to the potential responsiveness of pastures to fertiliser nutrient additions. About 70% of farms had soil phosphorus (P) tests below optimum values, indicating that pasture production would be increased by addition of P fertiliser on these farms. Similarly,about 50% of farms hadbelow-optimum levels of sulphur (S) and potassium (K). Pasture production on most farms was limited by more than one nutrient and a relatively high proportion of pumice soils had low levels of P, S and K. Pumice soils are prone to large leaching losses of added sulphate S and field experimental results indicated that elemental S (in sulphur superphosphate) was more efficient at increasing pasture production on these soils than sulphate S (in superphosphate). Soil test data was also used to indicate that about onethird of sheep and beef, andone-half of dairy farms were suitable for use of slow-release reactive phosphate rock (RPR) as a source of P, as indicated by soil pH56.0 and MAF fertiliser P requirements at or above maintenance levels. Keywords soil test, fertiliser requirement, phosphorus, sulphur, potassium, slow-release fertiliser
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(128 KB)Seeds mixtures for New Zealand pastures developed from British practices with sowing of multi-species seeds mixtures during early years of settlement. Breeding and seed production of ryegrasses and clovers in the 1930s led to use of simple mixtures, still the most commonly used. Since the mid 197Os, new species have been released, and are now becoming more popular. Advantages and some potential problems of species mixtures are outlined, and simple concepts of compiling seeds mixtures are explained, with particular reference to seeding rate and sowing time. Keywords species, seeds mixtures, pasture renewal, sowing rates, seedling establishment, competition
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(95 KB)A computer program called Stockpol is described. It is a biological model designed for decision support applications on pastoral farms. Individual farm scenarios are defined in terms of component subfiles which define stock (numbers and performance), land (area, pasture growth rates and land use), prices and constants. Physical and financial reports are available for individual scenarios, and for comparisons among scenarios. Once defined, scenarios are tested for biological feasibility by calculating if there is enough pasture cover on the farm at all times to meet animal requirements for targetperformance levels. Policies for biologically unfeasible farms can be automatically modified if necessary. Stockpol can be used to analyse long-term policy changes or short-term feed budgets, but it is not suitabIe for paddock-level feed budgeting. Keywords sheep, beef, pasture growth, pasture cover, feed budget, biological feasibility, prices, profits, computer model
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(75 KB)A spreadsheet model has been developed to allow a comparison of policies for beef breeding cows. The criterion for comparison is the kg of calf weaned per kg of winterfeed required i.e. efficiency. The model allows adjustment in number of animals wintered so that all policies have the same winter feed requirement. Policies which favour higher efficiencies include: timing mean calving date at the end of the winter, using breeds of bull with high growth rate and high survival rate progeny, older rather than younger herd age structures. and wintering only pregnant heifers and cows after pregnancy diagnosis. The most scope for improving efficiency is in herd age structure while the least scope is in calving date. The analysis demonstrates that that the most efficient options are a combination of policies. The best combination is about 26% more efficient than the worst combination. National beef herd statistics are required to assess the likely impact of changes on the industry. Keywords: beef cows, weaning weight, herd age structure, pregnancy diagnosis, feed requirements, time of calving, terminal sires
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(73 KB)Detailed studies of plant growth processes are important in understanding the performance and persistence of species in pastures, particularly in response to uncharacteristic environmental stress. The morphology of perennial ryegrass plants in mixed sheep grazed pastures was determined in self contained farmlets undercontrasting managements of rotational grazing, set stocking or a combination of both. Average size was 90 mg total DW, with 4- 5 tillers and 12-13 leaves, little different to white clover. Ryegrass exhibits strong clonal growth, with extension at the apex and death of the basal stem releasing branches to form new plants at regular intervals, maintaining a stable population structure of small plants all year. The normally short internodes on ryegrass stems can elongate to form stolon and elevate the apex to a more favourable position if survival is threatened. On average only 2530% of plants contained stolon at any one time. Because of high plant density the quantities of ryegrass stem present was often in excess of that produced by white clover in the same swards. Grazing management did not affect plant structure (numbers of tillers, leaves etc) only their size (dry weight), but had marked effects on pasture structure and subsequent survival of plants under stress. Keywords perennial ryegrass, plant morphology, grazing management, seasonal variation, plant survival, stolon formation
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(332 KB)Oversowing Lotus uliginosus cv. ‘Grasslands Maku’ offers considerable scope for improvement of understorey forage production in New Zealand’s plantation forests. In a grazing trial in Kaingaroa Forest annual forage yields of predominantly Maku lotus were 3000-5000 kg/ha dry matter (DM) from tree age 4-7 years but declined to 1000-3000 kg DM/ha by age 11 years. Forage yields available for grazing under different tree stockings (100,200 and400 stems/ha) were (up to treeage 11) approximately the same, in spiteof the percentage area covered with slash being significantly affected by tree stocking. Forage species composition since time of oversowing has changed from initial stands of almost pure lotus to a mixture of lotus and lower fertility grasses, particularly Yorkshire fog, and flat weeds. By tree age 11 years (8 years after oversowing) lotus comprises 20-30% of understorey ground cover, both with and without cattle grazing. Keywords Maku lotus, forest understorey, forest grazing, oversowing, forage yields
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(161 KB)The ability of the beef cow to buffer herself against pasture variability by losing liveweight at certain periods in the production cycle is reviewed. The point is made that this attribute of the beef cow can be used to buffer other enterprises on the farm less able to cope with variability in pasture feed supply. It is suggested that a farm livestock policy should include livestock classes like the beef cow which, because of their ability to buffer against variability in pasture feed supply,canresultinamoreefficient, and more economic use of pasture on the farm. Keywords Beef cow, nutrition, pasture variability, flexibility, buffering capacity, risk management
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(99 KB)This paper describes the research method adopted to identify the constraints to biological (chemical-free) sheep and beef production and to develop management systems that overcome these constraints. The method adopted to meet these objectives has three distinct phases; I A farmlet study, II Component research, and III Farmer survey and on farm testing. The objective of the farmlet study was to establish two farmlets, initially as similar as possible in terms of stock numbers and management practices. The only constraint imposed on the biological and not the conventional farmlet, is that the management practices must comply with the production standards of the New Zealand Biological Producers Council. The conventional farmlet acts as a baseline against which the performance of the biological farmlet can be compared, and to identify constraints to biological hill country sheep and beef production. Component research is used to investigate alternative methods of overcoming these constraints. The third phase of the programme is to survey practising biological producers, which number 50 at present, to identify their major constraints to production and to describe the management practices of successful biological producers. The information from this survey could then be used to further develop the biological farmlet and component research programme. Progress to date in the farmlet study and the information system used to manage and evaluate the performanceof the conventional and biological farmlet is also detailed. Keywords: biological, chemical-free, alternative farming, hill country, research method
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(93 KB)Pastures in the northern North Island contain a complex of nationally distributed insects and insects associated with warmer climatic conditions. Argentine stem weevil (Listronotus bonariensis (Kuschel)) is the most important insect pest in New Zealand. Progress toward the development of sustainable control of Argentine stem weevil is basedon a thorough understanding of the population ecology of the pest.The population size of Argentine stem weevil depends on the number of Acremonium lolii-free ryegrass tillers in the sward. Identification of A. lolii-free ryegrasses that are tolerant/resistant to Argentine stem weevil may improve ryegrass production and persistence without endangering animal health. The release of a South American parasite and the utilisation of naturally occurring pathogenic fungi together with tolerant/resistant ryegrasses has the potential to provide long term sustainable control of Argentine stem weevil in pastures . Keywords: endophyte, plant resistance,pathogens, biological control
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(351 KB)Estimates of the wastes produced in the Bay of Plenty region indicate that 22 million m’ (tonnes) is produced annually. The main contributors to waste production are the dairy industry (shed, factory),municipal sewage, pig, poultry, meatworks, kiwifruit, fishing and pulp and paper industries. In fertiliser terms these wastes are valued at $7.7 million. In addition the timber industry produces > 1 million tonnes of timber residues (sawdust, bark, woodchips) approximately 20% of which is currently dumped. Wastes, when recycled back on to the land, offer a potential source of nutrients to enhance pasture and crop production. In addition organic wastes provide a source of organic matter which may have beneficial effects on the physical properties of soils. Research results indicate that pumice soils are well suited to the application of wastes. Some general recommendations are given for the use of wastes in dairying, orcharding and cropping situations. Three factors are considered important for the successful utilisation of wastes (a) application rates need to be balanced to the nutrient needs of the soil-plant system (b) safeguards in the form of regular chemical monitoring of the effluent, soil, plant and animal need to be implemented, and(c) the economics of using the waste materials must be favourable to the farmer and orchardist. The principle of the producer of the waste paying for its safe disposal or utilisation needs to be adopted in New Zealand as it has in many overseas countries. Keywords nutrients, organic matter, waste recycling, pumice soils, fertiliser value
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