Based on farm trials and observations, a management system is recommended that covers three criteria: (a) an above-average stocking rate; (b) high per head performance; (c) very low cost. The main features of the system are: (a) rotational grazing all year on grass; (b) ewes and hoggets. have separate rotations for most of the year; (c) rotation lengths are designed to achieve maximum available feed at times of high animal intake; (d) supplementary feeding is minimal. The major advantages, cost savings, and limitations are described. Future research needs to optimize this system are discussed.
At a high country sheep station in Central Canterbury a study was made of the grazing behaviour of sheep. For three summers, between approximately late October and early April, the distribution of an average of 250 dry sheep grazing 590 ha of a 6200 ha summer range was recorded. During the third season, levels of dry matter and water contents of available inter-tussock vegetation were measured, the visual abundance of plant species in cut samples assessed, and diet determined using faecal cuticle analysis. Digestibilities of some available dry matter samples and selected plant species were also measured. Sheep activities were monitored.
The contribution of perennial ryegrass to pasture production is dependent on the stage of development of the pasture, climate and pasture management. Although variability in the percentage of ryegrass in improved pastures is less than in developing pastures, changes in the ryegrass component in response to different managemcnts can be marked. Tiller counts demonstrated a lower population of ryegrass tillers under rotational grazing by cattle than under sheep. This was increased by changing either from cattle to sheep grazing or by hard set stocking with sheep during spring. Grazing to 3 cm produced more dense ryegrass pasture than grazing to 6 cm. Severity of grazing appeared to be particularly important in dry conditions when grazing below 3 cm is likely to reduce tiller density. A range of management options is therefore available to encourage the perennial ryegrass component, and thus total dry matter production, of improved pasture.
The effect of two stocking rates (16 and 32 ewes/ha) and three initial levels of pasture reserves (1730, 2240 and 2720 kg DM/ha) on animal and pasture production was studied from June to December 1977. Total amount of pasture grown was unaffected by either stocking rate or pasture reserve. At 32 ewes/ha, 96.9% of net pasture production was eaten and no surplus conserved. At 16 ewes/ ha, 50.4% was eaten and 1120 kg DM/ha conserved. Increasing initial pasture reserves gave increased ewe liveweight at weaning at 32 ewes/ha, but no response at 16 ewes/ha. There were no treatment effects on single lamb birthweights or weaning weights. The relationship between ewe intake and pasture allowance at different physiological states is discussed.
A description is given of the farm, soil type, stock numbers, etc., together with an account of the management policy followed. The various methods available for providing feed for periods of insufficient growth, and the reasons for a change from the traditional methods to an all-grass system for wintering ewes, are stated. An analysis is given of the advantages and disadvantages of such a system, together with the methods of easing its planning and adoption. Reasons are given for a small area of swedes or choumoellier still being grown for wintering the ewe hoggets, rather than the complete adoption of an all-grass wintering for all stock. Reference is made to peat swamp development and the use of Roundup (glyphosate) in cutty-grass control.
IN September 1964, the New Zealand Grassland Association sponsored the establishment of the Grassland Memorial Trust to commemorate the lives of men who had made outstanding contributions to fostering progress in the science and practice of grassland farming. The men first commemorated in this way were the late Dr Peter D. Sears of New Zealand and the late Sir R. George Stapledon of the United Kingdom.
A grazing study was conducted on irrigated Wairau lucerne (Medicago sativa L.) ‘during summer and autumn using mixed-aged ewes. Two treatments were imposed: grazing durations of 3 and 12 days, with similar spells to the early flower stage of growth between successive grazings. This was carried out over two grazing and regrowth cycles.
Mature perennial ryegrass plants in pastures persist through the asexual reproduction of the tiller. Leaves are initiated from the flanks of the tiller stem apex. Generally, two leaves arc growing on a tiller at any one time. New tiller buds may arise from the axils of mature leaves depending on environmental conditions. Flowering results from a physiological change at the stem apex, which then produces a seed head but no further leaves, eventually resulting in the tiller dying. This phenomenon and other environmental changes result in marked seasonal trends in ryegrass tiller .densities. Leaf, tiller, and root production rates are sensitive to light and temperature where nutritional factors are not limiting. Tillering rates also change with stage of regrowth after defoliation. These factors are discussed with reference to their role in determining seasonal trends.
Dry matter accumulation patterns in pastures are the net result of two processes: the growth of new herbage and the death, and disappearance of old herbage. The relative importance of these two processes in influencing regrowth is discussed and illustrated with data from two markedly different pasture types. In a Nui ryegrass/ white clover pasture and a pure Maku lotus sward, defoliation intensity and season markedly influence the accumulation of dead material, its subsequent disappearance, and hence net dry matter production. The effect of new growth on dry matter accumulation was greatly diminished by within-canopy dry matter losses. The implications of herbage death and disappearance are discussed with reference to the adequacy of certain experimental techniques in estimating herbage dry matter production.
‘GRASSLANDS TAMA’ Westerwolds ryegrass (Lolium multiflorum Lam.) is a tetraploid cultivar of an extreme annual form of Italian ryegrass, bred in New Zealand and released into certification in 1967 (Barclay and Vartha, 1966) . Tama has been used mainly as a greenfeed crop to provide high quality production feed for use in late pregnancy and early lactation and should not be confused with winter maintenance feed crops such as swedes and turnips. Seed sales of Tama on the domestic market have declined in recent years, no doubt caused in part by the high cost of seed and by poor performance from sowings in dry autumns. To ensure reliability of Tama feed supply in late winter-early spring, correct husbandry in the previous months is required. It is the purpose of this paper to review this husbandry in the light of recent research findings.
An experiment comparing two self-contained grazing systems is described in which a high stocking rate of ewes (23/ha) is compared with a moderate rate (19/ha) which had an induced high lambing percentage. Yields of animal products and pasture utilization patterns are presented and demonstrate the advantage of fitting animal requirements as closely as possible to pasture production. This advantage is emphasized in winter feeding patterns. Some conclusions on management as it affects the technique of “all grass wintering” in Southland are discussed.
Field experiments have been conducted for 6 years at Hunua in North Canterbury to compare a range of grass and legume cultivars for sunny aspects of dry hill country. The most suitable legumes were Woogenellup subterranean clover and College Glutinosa lucerne. White, red and alsike clovers, Lotus corniculatus and L. pedunculatus did not survive summer droughts, while Trifolium ambiguum was low producing. Of the grasses, Grasslands K1950 cocksfoot showed promise, being drought resistant, coal season active and easily established from ovcrsowing. Perennial ryegrasses, Grasslands Apanui cocksfoot and Grasslands 4710 tall fescue did not tolerate severe droughts. Recommendations are given for establishment and management of the most promising species for this environment.
IN THIS PAPER I want to deal with how stock management and pasture management are fitted to the benefit of performance of both. These two aspects are not always easy to separate, hence both managements tend to be welded together with some degree of compromise for the maximizing of the end product-meat and wool. I have found perennial ryegrass associated with white clover to be the one grass able to fit these demanding requirements, under fairly heavy stocking rates.
I FARM 145 ha in partnership with my father at Brydone, which is 21 km south of Gore. The farm is flat and is on three levels. One-third of the area, containing Edendale soils, is situated on a terrace 20 m above the flood plain of the Mataura River. The remaining area below the terrace consists of Mataura soils, apart from some 12 ha of sands and gravels. The fertility of this small area has been built up by heavy winter stocking to enable pasture and lucerne to be established successfully. The Edendale soil, which is developed on deep deposits of windborne material, is the heavier of the two soils, with 18 to 20 cm of topsoil. Gravels occur at about 4 m. The Mataura soils, developed on alluvium, are of variable texture, and gravels may occur at a shallow depth. Both soils are free-draining, but during a dry period, as experienced last summer, the superior moisture-retention properties of the Edendale soils are apparent. Annual rainfall approximates 960 mm and is usually well distributed. Frosts to -10”~ can be expected between May and September. I consider winter to last 90 to 100 days. The property is subdivided into 20 paddocks ranging in size from 1.5 to 8 ha. Stock in each paddock has access to water, and the wholle farm is reticulated with a wire from a mains electric fence controller. The 8-ha paddocks are tm large for maximum pasture utilization unless they are stocked with all the ewe flock, and although it is planned to subdivide them permanently, a temporary electric fence is used at present.
In the period 1973-77, 71% of pasture grasses certified in New Zealand were perennial ryegrasses. Data from one of the major seed merchants showed that during 1977-8 Ruanui comprised over 70% of the retail sales of perennial ryegrass cultivars, while Nui (17%) and Ariki (10%) were also important. Comparative production data between the New Zealand bred cultivars, some overseas cultivars and some uncertified local populations are presented. Overseas cultivars are generally inferior to New Zealand cultivars but some local populations are very promising in a number of environments. The newer cultivars Nui and Ariki often show a greater yield response to longer intervals between defoliations and increased nitrogen supply than Ruanui.
Eighty-two white clover lines from overseas and 13 hill country collections from within New Zealand have been examined on a hill country site for their persistence and production potential under sheep grazing on infertile soils. By the third year of the trial only seven lines were equal to or better than Huia. These included only two overseas lines (one cultivar from France (‘Crau’) and a line from New Hampshire, U.S.A.) and five of the 13 collections from New Zealand hill country. This is considered to be a strong argument for the use of New Zealand material in breeding white clover for New Zealand hill country conditions.
ONE OF THE reasons for poor lambing performances in South Otago has been the light weight of two-tooth ewes at mating. From weighings done on a number of farms it appears that to achieve satisfactory two-tooth weights it is a prerequisite that a certain liveweight has to be achieved at the lamb stage, before the first winter. This target is well above the weight being achieved on most farms.
The build-up in general soil fertility and productivity in eastern Southland and West Otago are discussed, with references to indices such as sheep numbers, grassland fertilized and fertilizer sown. Annual and seasonal dry matter production figures from browntop dominant and ryegrass dominant swards are compared. Reference is made to the decreasing importance of winter fodder crops in the region as soil fertility has built up and as pasture growth has been extended. Wintering systems for ewes, hoggets and cattle using grass, hay and grain are discussed. The implications of a rotational grazing system with ewes and lambs in early spring are reviewed, and topics for future research to try and harvest the spring-summer flush of growth are suggested.
A series of experiments investigating the response of several pasture grasses direct drilled into existing swards is reported. The technique has relevance to pasture renovation, improvement of winter forage production, and more rapid introduction into farming of improved pasture cultivars. Improvements in coulter design and use of pasture desiccants were coupled with direct drilling to assist plant establishment. It appeared that aggress,ive cultivars such as Nui and Tama ryegrasses were best suited to establishment by these techniques, and that lower seeding rates than those normally recommended were very successful. Methods of improving winter herbage production by using winter-active ryegrass cultivars without the need to resow to pasture in the following spring are discussed.
The seasonal pattern of nitrogen mineralization is described and compared with the potential demand for nitrogen by grasses. Peak mineralization rates occur in spring but are quite inadequate for expression of potential grass growth. Nitrogen fixation by clovers provides a significant input into the system over a short period. Consideration of the fate of fixed nitrogen shows that losses largely o&et this input unless it is maintained at a high level. The role of pasture management and fertilizer practice in this maintenance is stressed. Seasonal differences in nitrogen transformations and their influences on nitrogen losses are discussed.
A current review of some general aspects of herbage quality and its evaluation is presented. It is concluded that the two-stage in vitro digestion procedure is a reliable predictor of in viva digestibility, and that the more time-consuming chemical analyses can be used to indicate changes in the herbage which may explain observed digestibility changes.
The nature of net soil nitrogen mineralization and its implications in Soil under fallow and wheat were investigated in field and pot experiments.
The pattern of production from permanent pastures on two major soil groups in Southland and some factors affecting production are discussed. Production was shown to be lower on the summer droughtprone YGE/YBE intergrade soils compared with the wetter southern YBE. The major proportion (80%) of the production occurred in spring and summer. Grasses contributed two-thirds and white clover one-third of the annual production. Inadequate mineral nitrogen levels in soils over the spring result in seasonal responses to nitrogen fertilizers. The use of high rates of nitrogen fertilizer at regular intervals throughout the year increased total pasture production by about 25%. The clover cyst nematode was shown to reduce white clover establishment and production in field trials.
Three methods of sheep diet determination were compared at Brooksdale Station during one time of the year under conditions of declining herbage availability.
This thesis reviews the development over the past 30 years of an area of light land in Mid Canterbury, New Zealand. The aim is to examine the effect that irrigation has had on this development. Development is defined in terms of increased production, greater flexibility, or more intensive land use. Both archival research and a survey of a 30% random sample of farmers is used to gather base data from an irrigated and adjacent dryland zone. These zones have similar cultural and physical characteristics.
In a trial conducted at Ruakura over 5 years, mixed-age flocks of Coopworth, Perendale, High Fertility Romney and Control Romney ewes were run on separate farmlets stocked at 26, 21 or 16 ewes/ha. At any given pasture allowance the Coopworth ate more pasture than the other breeds. Lambing performance, weight of lamb weaned and fleece weight were curvilinearly related to allowance. Lamb production per ewe tended to level out at a DM allowance of 4 kg/ewe/day for the Perendale and about 5 kg/ewe/day for the other breeds. Pasture allowance accounted for an appreciable amount of variation in animal production between years and stocking rates; litter size, 38 to 90%; lambs weaned/ewes mated. 29 to 71’%; weight of lamb weaned/ewe mated, 26 to 62%; and fleece weight, 25 to 49%. Pasture allowance accounted for the least variation in all variables in the Perendale compared with the other breeds.
This study evaluates the influence of climate in the development of agricultural water supplies in Canterbury. A discussion of the historical and spatial occurrence is presented, as well as a description of the suitability of the region to such development.
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