New Zealand - part 3
The description of dominant farm classes within a specified Agro-Ecological environment was presented above in section 4.
Development of the pasture resource
Pre 1850 settlement
Post 1890 settlement by Europeans
From 1920 onwards innovation in science and technology allowed intensification of farming systems. Improvements included mechanisation, amelioration of soil fertility through improved understanding of nutrient requirements for plants and animals, advances in plant and animal breeding and health issues. More recently diversification and improvements in the quality of products produced has dominated. These improvements have been made while maintaining or improving agricultural efficiency to allow production to remain competitive in international markets.
Initially, new pastures were developed from forest by felling of timber which was then left to dry. It was then burnt and pasture seed was broadcast by hand over the ash. Multiple species seed mixes (containing up to 10 different grass and legume species) were recommended for ‘bush burn’ pasture establishment into the 1950s at total seed rates of 20-40 kg/ha. Once established, pasture and regenerating native seedlings were grazed by sheep and cattle and pastures were fully stocked within 12 months of initial tree felling. Later any large tree trunks, which remained after felling, would be hauled out and burnt. This removal of tree stumps may not occur for up to 20 years after the initial tree felling.
Post clearing “Bush sickness” after forest clearing
Development through improved soil fertility
Because of the large proportion of pastures on land with slopes >16° much research was conducted to determine the effects of slope and aspect on pasture production. Important aspects of this work included the effects of stock behaviour in nutrient transfer, seasonality of production (see below) and differences in aerial fertilizer distribution patterns. This information has been used since the 1970s to develop on-farm grazing management systems, aid subdivision decisions and stratify fertilizer applications. Superphosphate applications totalled 794 000 t in 1981 and increased to 1 270 000 t in 2007 while lime applications were 1 355 000 t in 1981, decreased to 561 000 t in 1987 following agricultural reforms, but have increased to 1 487 000 t in 2007.
Hill country development
Nitrogen use for pasture production
Dairy farms account for 235 000 ha of the total irrigated land and 111 000 ha of pastoral land used for sheep farming can be irrigated. About 62 000 ha of irrigated land occurs in cropping and mixed cropping systems and a further 51 000 ha on cattle or mixed sheep and cattle farms.
Pasture growth patterns
Temperature effects on production in summer moist regions
Production in summer dry regions
Seasonal variation in mean daily growth rates
Effects of topographyBecause a large proportion of intensive pastoral production is conducted on hill country in
Aspect and slope
Botanical composition of pastures on and near stock camps is strongly influenced by increased N and P fertility and the degree of soil moisture deficit at different sites. At Ballantrae in the Manawatu, annual DM yield production of unimproved pasture was 2.8 on the north aspect, 3.0 on the west, 9.7 on the east and 3.6 t DM/ha on south facing aspects (Lambert and Roberts, 1978). Botanical composition was dominated by native Notodanthonia grass species on the north aspect; perennial ryegrass and mouse-eared chickweed (Cerastium glomeratum) on the south; Yorkshire fog on the east and south and Nertera setulosa in the west and south aspects. Browntop and sweet vernal had similar cover at all sites probably due to their wider tolerance of soil fertility and environmental conditions.
Grass endophytesPerennial ryegrass endophytes
Endophyte (Neotyphodium lolii) was first identified in perennial ryegrass in
The presence of endophyte is vital to maintaining long-term productivity and persistence of ryegrass based pasture due to the protection it offers against pests. The presence of wild type endophyte has been shown to deter black beetle (Heteronychus arator), cutworm (Graphania mutans), root aphid (Aploneura lentisci), porina (Wiseana cervinata) and pasture mealy bug (Balanacoccus poae) (Easton, 1999). Another major pest affected by endophyte is Argentine stem weevil which has been estimated to cost the pastoral industry NZ$ 46-200 M annually through pasture damage (Prestidge et al., 1991).
To maintain protection from insects and minimise livestock health issues novel strains of endophytes, such as AR1 and NEA2, have been developed. These endophytes are non-existent in the neurotoxic lolitrem and ergovaline but contain high levels of peramine, an alkaloid to which Argentine stem weevil is very sensitive.
However, peramine is not a broad spectrum pesticide and consequently
further development of novel strains continues. The recently released
AR37 endophyte does not produce peramine, lolitrem or ergovaline alkaloids.
It does produce epoxy-janthitrem compounds which confer pest deterrence
to a wider range of invertebrate pests than the AR1 endophyte. Some
staggers may still occur in livestock grazing AR37 infected ryegrass.
Farmers in the warmer areas of
Tall fescue endophytes
Research is continuing to develop novel endophytes. The aim is to ensure pasture yield and persistence from ryegrass and tall fescue based pastures is maintained at levels comparable to wild type endophyte infected pastures but avoidance of adverse effects on livestock.
The development of new pasture and forage cultivars is ongoing and commercial companies often work in association with Government owned Crown Research Institutes during breeding, selection and development. Locally bred, pest and disease resistant cultivars which are suitable for grazing or conservation are most widely sown but some cultivars bred in Europe, North America, Argentina or Australia are also sown. These cultivars may have cool season activity or may tolerate more frequent grazing.
Cultivars of browntop, Yorkshire fog, Caucasian clover (T. ambiguum),
Lotus pedunculatus, L. corniculatus, alsike clover (T.
hybridum) and sulla (Hedysarum coronarium) have been developed
for use in
Use of alternative pasture species, which have definite advantages
in specific environments, is often restricted due to difficulty in establishment,
perceived high cost of new species and widespread promotion of ryegrass/white
clover pasture technologies. For example, Caucasian and strawberry (T.
fragiferum) clovers are perennial legumes suitable for some
Selection of the appropriate pasture species depends on the environment where it is to be sown. Table 12 shows that ryegrasses are highly suitable for inclusion in moist lowland environments (Farm Class 5, Section 4) but are less suitable for South Island High Country properties (Farm Class 1, Section 4). In moist hill country (Farm Class 4, Section 4) recommended grasses include ryegrass, cocksfoot and grazing bromes (Bromus stamineus and B. valdivianus) while lotus, white and red clovers are the most suitable legumes. Species suitable for use in farming systems which experience periodic water stress (“dryland”) include; cocksfoot, bromes, tall fescue, lucerne and subterranean clover.
Pastures for warm, summer moist regions
Subtropical C4 grasses such as paspalum (Paspalum dilatatum) and Kikuyu (Pennisetum clandestinum) may dominate pastures in moist northern areas of the North Island when perennial ryegrass has lost vigour after stress periods (insect damage, summer drought, winter pugging). These aggressive C4 grasses are vigorous in the warm summer and autumn but have lower production in winter and spring when temperatures are outside their optimum ranges. Their quality is inferior to perennial ryegrass. Frequent pasture renovation is often required to control Kikuyu particularly in the Northland region. Glyphosate is used to control C4 grasses prior to overdrilling perennial ryegrass. Insect damage in the warmer North Island regions is more severe than farther south and suitable novel endophytes (see above) in ryegrass and tall fescue cultivars are therefore recommended.
Cool, summer moist regions
Dryland pasture options
These environments develop summer soil moisture deficits because of combinations of low annual or seasonal rainfall (<700 mm/yr), high warm season evapotranspiration, and shallow, stony soils with low waterholding capacity. Cocksfoot is the second most commonly sown grass in New Zealand and is used for these regions. It is less affected by drought than perennial ryegrass and persists and recovers leaf area and growth more rapidly than perennial ryegrass.
White clover performs poorly in these dry environments especially after the loss of its taproot 12-18 months after sowing. Subterranean clover cultivars imported from Australia are recommended as the main companion legume in cocksfoot based pastures. The annual life cycle of subterranean clover means that it produces high quality spring feed before and during flowering and it then buries its seed burrs in November/December to complete its life cycle. This nullifies competition for scarce water between the grass and legume in summer months. At “Tempello”, a dryland hill country farm in Marlborough, pre-weaning lamb growth rates on a dryland subterranean clover dominant hill country property have increased with improved subterranean clover management from 227 g/hd/d in 2001 to 328-402 g/hd/d (Grigg et al., 2008). Meat produced from the 2 800 ha of effective land (4 800 ha total area) has increased from 60 to 76 t liveweight/year despite a 12% drop in total ewe numbers. Lamb weaning weights have increased from 27 kg LW/hd (2001) to 32.5 kg LW/hd in 2006.
In years with moist summers, volunteer white clover may be a valuable component of dryland pastures. Other annual clovers are currently being tested on dryland farms and several adventive clovers, medics and lotus species are common in lower fertility dryland pastures.
The area in lucerne is rapidly expanding with recent demonstrations of high productivity and profitability. For example, in Marlborough at “Bonaveree” farm with a mean annual rainfall of 530 mm, the area in lucerne has more than doubled from 120 to 300 ha between 2003 and 2009. This lucerne was direct grazed with only true surplus herbage conserved. The economic farm surplus has increased from NZ$ 30/ha to almost NZ$ 140/ha even though annual rainfall decreased over the same period. In 2006/07, lambs averaged 396 g/hd/d from birth to weaning and over 80% of lambs were finished and sent for slaughter by mid December at 13-14 weeks of age (Avery et al., 2008).
Increasingly, where water is scarce for growth, this deep rooting, high quality species is sown on the deepest soils to extract moisture from depths that are inaccessible for grasses. Yields vary throughout the country which reflects differences in environment, soils and management. Annually yields can range from <3.0 to >28.0 t DM/ha.
The quality, particularly crude protein and metabolisable energy, of lucerne herbage is strongly affected by regrowth duration because of changes in the leaf:stem ratio (Brown and Moot, 2004). Recent changes in lucerne grazing management have been critical for maintaining stand production and persistence (Moot et al., 2003). Failure to allow adequate partitioning of carbohydrates to roots by allowing adequate regrowth duration (>5 weeks) between grazing events and preventing flowering in late summer or autumn reduces potential production in the following year (Teixeira et al., 2008). In New Zealand lucerne is rarely sown in mixtures because of its need to be rotationally grazed throughout the year. However, some farmers may sow lucerne in mixes with prairie grass to produce cool season feed while in cool dry areas cocksfoot is useful to combat wind erosion.
Alternative pasture grasses
Bromus species provide greater cool season production than perennial ryegrass but tend to be vulnerable to insect pests and perform poorly on acid soils or poorly drained sites. Timothy has very small seed (~0.4 g/1 000 seeds) compared with perennial ryegrass (2.0 g/1 000 seeds), thus establishment can be compromised when sown too deep. Furthermore, field emergence is slow for timothy (230°Cd) compared with 160°Cd for ryegrass so timothy seedlings are out-competed at establishment (Moot et al., 2000). Timothy is a late flowering grass which retains nutritive quality later into the season, and is less competitive with companion legumes, than ryegrass. It is frequently used in hay crops. Phalaris is valued as a minor component of multiple species pasture mixes as it tolerates root attack by grass grub (Costelytra zealandica) but is rarely used as the primary grass species because it may cause irreversible staggers in livestock.
Low fertility pastures are frequently browntop dominant. This mat forming perennial tends to exclude more desirable species through its ability to compete for water and nutrients, predominantly scarce phosphorus. In moist hill country it may be suppressed by mob stocking at high rates in winter. Heavy trampling then tends to favour ryegrass/white clover. Other introduced grasses which may invade improved pastures over time include: sweet vernal, crested dogstail and Yorkshire fog.
Annual weed grasses are Poa annua, barley grass and Vulpia spp. In addition, C4 annuals such as barnyard grass (Echinochloa crus-galli) and summer grass (Digitaria sanguinalis) are common in warmer, summer dry regions (northern North Island). Annual ripgut brome (Bromus diandrus) and the perennial Chilean needle grass (Nassella neesiana) are major grass weeds in hill country which are capable of creating serious livestock health issues and contamination of wool, skins and carcasses which may be rejected during processing.
Pasture renewal (see below) is required as pasture productivity and quality declines. Species such as Poa annua, shepherd’s purse (Capsella bursa-pastoris), chickweed (Stellaria media), fathen (Chenopodium album), nightshade (Solanum nigrum and S. physalifolium) speedwell (Veronica persica), twin cress (Coronopus didymus), cleavers (Galium aparine), mallow (Malva spp.), horehound (Marrubium vulgare), hawksbeard (Crepis capillaris), hawkbit (Leontodon taraxacoides), catsear (Hypochaeris radicata), dandelion, thistles (scotch, nodding, Californian), Hieracium spp., gorse and broom (Cytisus scoparius) are all common pasture weeds. The woody weed species such as gorse, broom and sweet brier are particularly expensive to control while horehound may present significant problems in lucerne stands. In dairy pastures giant buttercup and ragwort are major weeds in some districts.
In most cases, crop rotations, fallow periods, cultivation and grazing management are the most common methods of weed control. Use of pest and disease resistant cultivars and timing farming operations to minimise potential for pest attack or disease are also common practice. Use of chemical control for weeds, pests and diseases is common in susceptible arable and horticultural crops and, when necessary, in establishing pastures and forage crops.
In established pasture chemical control methods are only triggered when failure to control the degradation caused to the pasture will result in an economic loss. For example, annual dicotyledonous weeds may be tolerated in established pastures but ingress of perennial rhizomatous weeds such as Californian thistle triggers a combination of control methods. In spring and summer, thistles are permitted to form seedheads but these are topped before the seed matures. This depletes reserves in rhizomes. In autumn, as the plant begins allocating carbohydrate below ground, a systemic herbicide is applied which is also translocated throughout the root system. Herbicide selection depends on whether the thistle has invaded a monoculture or mixed species pasture. A broad spectrum broadleaf herbicide is applied to grass or cereal monocultures. In a mixed species pasture containing grass and legumes the broadleaf herbicide should be selective so legumes are not killed.
Several successes have been achieved with biological control of pest insects. Notable examples include the introduction of the parasitoid wasp (Microctonus hyperodae) to control Argentine stem weevil and Microctonus aethiopoides as a parasitoid for Sitona discoideus a weevil which caused serious damage to lucerne.
Pasture renewal programs
In any pasture renewal program it is undesirable to replace the existing run-out pasture directly with new pasture, because such a sequence fails to address why the vigour of the existing pasture declined. It is recommended that 10% of a farm undergoes renewal every year although this may vary from 5-20% depending on the farming system.
Maize in pasture rotations
As a C4 species, maize is commonly grown in the warmer North
Island areas of
With both conventional cultivation and direct drilling the first herbicide is applied about one month prior to sowing maize and the pasture is grazed about 10 days later. The paddock is then cultivated and maize is sown. If necessary, the area is given a second herbicide application prior to direct drilling. Where problem grass species such as browntop, Kikuyu and summer grass are present these may be sprayed out the previous autumn and the paddock sown in Italian type ryegrass for feeding in situ over winter and early spring.
For successful pasture establishment it is desirable to harvest the maize for silage in mid March (autumn) rather than for grain that may not mature until May or June. Following harvest the paddocks are then sown back into pasture using either conventional cultivation or direct drilling. In some cases two or more maize crops may be grown prior to establishing a new perennial pasture. Cereal crops for grazing in situ may be sown in the period between the maize crops.
Brassicas in pasture rotations
If a brassica crop fails to establish then a winter greenfeed cereal, such as oats or barley, can be oversown into the paddock in April to minimise yield losses. Cereals are established at a rate of 80-120 kg/ha and can produce 2-4 t DM/ha of winter feed depending on soil fertility and time of sowing. Break-grazing using back fencing is essential if regrowth is required.
In most North Island Hill country properties (Farm Classes 3 and 4; Section 4) about 5-10% of the farm area can be cultivated. This area can be used to incorporate forages into the farming system. The rotations employed depend on financial considerations and the identification of expected periods of feed deficit. Where high quality summer feed is required for lamb and beef finishing (Farm Classes 5, 6 and 8, Section 4) a leaf turnip such as ‘Pasja’ is used. Kale, sown in late spring, allows transfer of feed from summer to winter months. The area available for summer grazing is reduced by establishing kale in spring but the bulk of dry matter produced by the crop is available as standing feed to meet stock demand in winter months.
When kale is used rotations are usually:
old grass pasture → kale (1-2 crops) →spring sown new pasture.
In environments with over 800 mm rainfall/yr kale can be sown in November (late spring) and can, with appropriate management, accumulate >20.0 t DM/ha by the following winter. However, yields can be highly variable (Table 13) depending on nutrient availability, environmental conditions and establishment and management practices. For example, in Canterbury, kale yields were 23.0 t DM/ha from an October sowing (8 months after sowing) and 17.0 t DM/ha for the December sowing (6 months) (Brown et al., 2007) and grew at a rate of 8 kg DM/ha/°Cd above a base temperature of 0°C. Kale is grazed ‘in situ’ and break fenced so stock are allocated a daily feed allowance. If two successive kale crops are grown in the rotation, yields from the second crop are generally lower than the first.
Pasture renewal programs in different farm systems
old grass pasture → Italian ryegrass for winter greenfeed → leaf turnip or rape for summer feed→autumn sown pasture.
This would ensure successful pasture establishment after autumn break rains, because spring establishment is unreliable.
South Island Finishing/Breeding properties (Farm Class 6; Section 4) employ rotations to ensure adequate feed is produced to meet livestock demand. This is because these systems experience cold winters and summer drought which limits pasture feed production (Moot et al., 2007). Crop rotations provide maintenance feed in winter months and green feeds are used to meet late winter/early spring feed demand which increases during lambing/calving and lactation. Annual greenfeed crops have the added benefit of depleting soil nitrogen following lucerne stands. Old lucerne stands, which are identified for renewal when plant population declines and perennial weed species begin invasion, are cultivated in early spring and left fallow until autumn when a greenfeed Italian ryegrass or cereal is sown. This is fed to stock in late winter/early spring and then cultivated by late October. The paddock is fallowed to accumulate soil moisture, and allow appropriate chemical weed control, until late January when turnips are sown to grow aided by the conserved soil moisture. Turnips are grazed in winter (July) allowing seedbed preparation in early spring before sowing another lucerne stand. If the paddock is being sown to pasture a second summer fallow is used to conserve moisture before the pasture is autumn sown.
Intensive South Island finishing systems (Farm Class 7; Section 4) are generally in summer safe environments. Their main period of feed deficit occurs in winter when temperature limits production from conventional temperate pasture species. There are two main pasture renewal practices (Moot et al., 2007). In the first, the old grass pasture is sown into swedes which are winter (June/July) grazed and then new pasture is sown in spring. Alternatively, a cereal crop is sown in October after the swedes and prior to establishment of the new pasture. These cereal crops are either used as whole crop silage or harvested for grain prior to autumn establishment of the new pasture.
|6. OPPORTUNITIES FOR IMPROVEMENT
OF PASTURE RESOURCES
New Zealand’s pastoral resource and integrated agricultural systems rely almost entirely on improved pastures developed by human activity. Prior to settlement the country was forested (see section 1 and Figure 2) and even the high country tussock grasslands, with their low stock carrying capacity (Farm Class 1, Section 4), would not exist without the repeated burning events that occurred for hunting. Thus, most of the opportunities for the future focus entirely on improved pasture species and their management.
Because the New Zealand economy is dominated by the success or failure of its pastoral industries it is important to initially discuss physiological limitations to pasture yield within its pastoral systems. Increases in pastoral production will come from intensification of land which is currently in pasture. The land area devoted to pastoral production has declined over the last decade and, given the country’s topographic constraints, it is unlikely that any new areas will be converted to pastoral agriculture. Intensification is on-going with increasing areas under irrigation, the conversion of sheep and beef farms to dairy production and the more intensive use of easier hill country.
Improved on-farm management
In the sheep and beef sector there are moves towards more stratification within the industry. This would ensure that the pasture resource is used more efficiently with store lambs and young cattle from hill country farms (Farm Classes 1-4; Section 4) being supplied to lowland intensive finishing farms (Farm Classes 5-8; Section 4) on contract. This closer integration between farm classes results in more secure returns for the breeding farms and a guaranteed supply of quality livestock for the finishing enterprises. This would also by-pass the fickle nature of store stock auctions. These developments are being accelerated by the increasing influence of large company owned farms which have a range of properties in both wet and dry regions. They are then ideally situated to use their complementary pasture resources by trucking livestock to graze high quality pasture at their various properties. It often makes greater business sense to move animals than buy conserved forages or to grow large areas of winter feed in a self contained family farm.
Management improvements on-farm over the next decade are likely to focus on increasing production efficiencies (e.g. per ha, per mm of water, per unit of P, S or N applied, per labour unit, etc). This will occur in parallel with attempts to decrease environmental impacts of intensive pastoralism. Amongst others, mitigation or reductions are required to 1) reduce methane and nitrous oxide gas outputs from ruminants and grazed pastures and 2) reduce nitrate leaching from winter forages grazed in situ and from urine patches. These two areas are current subjects of intensive research where some progress is being achieved.
Management technologies which will achieve greater resource use efficiencies and which are currently being demonstrated and promoted to farmers include:
The need to at least maintain production per unit area, given that there is no more land available for pastoralism, while facing the requirement that farmers must reduce the environmental impacts of intensive ruminant grazing, is the greatest challenge facing New Zealand agriculture.
The trend towards fewer larger farms, both corporate and family owned, will generate some economies of scale with bulk purchasing of inputs such as fertilizer and more importantly larger flocks and herds that will allow selection from a wider gene pool to breed animals which can more efficiently convert forage into milk and meat. However, the trend to larger paddocks on large farms may lead to less precise use of land where soils and topography may vary considerably over small areas.
Opportunities to overcome topographical limitations (also see section 5)
Over 60% of New Zealand’s pastoral land is on slopes steeper than 15° and pasture production is unlikely to reach the theoretical yield limits. Some of the physical limitations for hill country pastoralists include:
Interactions between topography, plant biology and climate, in most cases, cannot be altered. Hill country farmers must understand the negative effects these interactions can have on productivity and seek to minimise their potential effects. For example, nutrients will continue to be transferred from steeper slopes to high points and less steep areas of un-subdivided paddocks. More intensive subdivision of hill pastures and strategic placement of water and salt supplies (Gillespie et al., 2006) may moderate animal movement and grazing intensity of steep slopes. However, it seems that there is little that can be done to change the camping behaviour of free grazing livestock. Fencing dry warmer north and west slopes from cooler, later maturing east and south slopes is on-going current practice, as is the separation of higher producing rolling country from steeper mid altitude from cooler higher country, undeveloped shrub vegetation from productive pasture. As environmental imperatives become more urgent rivers, streams and steep eroding gullies will be fenced to exclude livestock.
Advances are being made using GPS technologies to more precisely spread fertilizer from fixed wing aircraft but helicopters, which are more expensive, would be required to achieve ideal placement over much of the finely dissected hill country of New Zealand.
Opportunities under dryland conditions
Nitrogen and legume use
The maximum yield which can be achieved from perennial temperate pasture species is about 28 t DM/ha/yr when N and water are non-limiting (Peri et al., 2002a) but high rates of N (>600 kg N/ha/yr) are required for C3 grasses to reach this maximum yield (Mills et al., 2006) and these are unlikely to be economically viable or environmentally sustainable for ruminant production systems. This rate also exceeds the arbitrary 200 kg N/ha/yr maximum N fertilizer rate set by environmental agencies. In contrast, nodulated legumes with N self sufficiency and efficient light capturing leaf canopies, such as lucerne, also have a potential yield of 28 t DM/ha/yr (Brown et al., 2005). Clovers with less efficient leaf canopies may have a yield limit of about 18 t DM/ha/yr as monocultures. This is at least 1.5 times the yield expected from typical perennial grass clover pastures where the clover content is normally only about 10% of total annual production. Such pastures are invariably N deficient because of low N inputs from the clover which struggles to compete with grasses.
While grass dominant pastures, which do not receive N fertilizer, may have the “optimum” crude protein levels for ruminants, such pastures generally have low grazing preference. Thus, voluntary intakes are low and animal production per head is about half that of animals on a high legume diet. Furthermore, animal production per hectare for grass dominant pasture with about 16% CP will be unsatisfactory because the pasture yield will only be about half that produced by a pasture where the grass has a CP of 25%. This is because temperate grasses require >4.0% N in their leaf DM for maximum photosynthesis (Peri et al., 2002b) and grass leaf with a CP of 16% contains only 2.6% N (16% CP/6.25). Such swards display obvious N deficiency with yellow/green leaves and low vigour. There is no obvious solution to this dilemma. Perennial grasses and herbs with reduced critical leaf N content (e.g. =3% N rather than >4%) may be developed in future. In the mean time high sugar grasses will not solve the problem. High energy supplements may help to balance ruminant diets but their cost is unlikely to be economically viable for unsubsidised meat production.
New Zealand pastoral farming must therefore get back to basics. It must ensure the lime, superphosphate, rain (+ irrigation) and sunlight reaching the land is used with maximum efficiency for carbon fixation (photosynthesis) and nitrogen fixation by legumes. The high rate of N fertilizer required to achieve maximum productivity from grass dominant pastures is unlikely to be affordable for a sustainable, unsubsidised pastoral industry.
Problems associated with intensification
Eutrophication of waterways has lead to nutrient application caps in some regions. The use of riparian buffers and adequate fencing to prevent animals accessing waterways is essential. There is potential for multiple species riparian vegetation buffers which allow plantings of strips of ungrazed deep rooted pastoral plants (e.g. lucerne) surrounding waterways to capture excess N at depth. This forage may then be cut, conserved and fed elsewhere. Trees closer to the waterways improve the habitat for aquatic life and create wildlife corridors. Furthermore, >30% of New Zealand’s total greenhouse gas emissions are N2O, predominately from urine patches, and recent work has shown that nitrification inhibitors can reduce total N2O emissions from urine patches by about 70% (Di et al., 2007).
Most of the following mitigation strategies are currently employed but much more general adoption of these will be essential if significant progress is to be achieved. Examples of these strategies are cutting and carrying of winter forages to reduce soil compaction on sensitive land. Animals may be housed in winter and/or feeding out may occur on less fertile paddocks rather than where feed was sourced. This increases costs but provides opportunities for more efficient distribution of the nutrients in effluent across specific targeted areas of the farm.
Farm nutrient budgets
Adjustment of legislation
Legislation to protect New Zealand’s "Clean green image" is likely to be strengthened and laws relating to environmental pollution issues are likely to be enforced more vigorously in the future. This is likely to result in more stringent controls on the use of nitrogen fertilizers, the spreading of effluent, and encouragement to plant riparian strips within fenced off waterways, particularly in dairying regions. Tree planting within steep erodible hill pastures may become obligatory and stocking rate limits on intensive dairy pastures may need to be introduced but as yet none of these measures have been publicly debated.
Farmers are impatiently waiting (2009) for definite legislation which will allow them to participate in the "Carbon Market". With about half of New Zealand's greenhouse gases calculated to come from livestock emissions pastoral farmers require strong market certainty regarding various mitigation measures which they may employ. Carbon sequestration by forest tree planting on less productive farmland is an obvious opportunity which is delayed pending legislative guidance. Current legislation will implement an emissions trading scheme in 2010 but agriculture is currently exempt until 2015.
Pasture plant improvement
Animal breeding programmes aiming to increase the rate of conversion of pasture into saleable animal products are making progress. For example, the recent increases in New Zealand lamb production from significantly reduced ewe numbers is partly attributable to advances in animal breeding, with an emphasis on fecundity and meat production.
New Zealand farmers are familiar with current perennial ryegrass cultivars, their wild and novel endophyte options and the range of white clover cultivars available. The use of this plant material for future plant breeding of these dominant pastoral species, through either conventional and/or genetic technologies may be limited by the lack of genetic variability in highly developed lines (e.g. perennial ryegrass). Market resistance to genetic technologies (both trans- and cisgenic applications) in the food chain is strong in New Zealand and in some high value export markets. This presents a dilemma for science policy and research fund allocation. On one hand New Zealand does not wish to neglect new genetic technologies but there is a risk that these products may never be accepted for inclusion in the food chain by the end consumer. Furthermore, there may be a large opportunity cost in funding genetic technologies rather than concentrating on plant and animal improvement using traditional techniques.
The introduction of pasture species, which show improved production and persistence to the industry standard perennial ryegrass/white clover mix in some environments, can fail to be exploited by rural industry in New Zealand despite the well developed information extension structure. A current example is Caucasian clover which has shown promise for long term production and persistence in montane and lowland pastoral systems. However, it has slow establishment caused by higher thermal time requirements for leaf development in its seedlings compared with white clover (Black et al., 2006). This has meant the species was often suppressed by vigorous perennial ryegrass seedlings when mixtures were established. It is now recommended that Caucasian clover is established as a monoculture or with a low sowing rate of a forage cover crop such as rape. It can then establish and develop its taproot and rhizome system without competition from a companion grass. Once the Caucasian clover is established perennial grass can be oversown. However, now the establishment is understood and recommendations can be made with confidence, the seed is difficult to obtain.
The success of fast establishing perennial ryegrass/white clover pastures means farmers can be impatient with such new species that may establish more slowly. The need to manage speciality pastures with more care can make changes required from the standard ryegrass/white clover management frustrating. Also, the dominant use of pasture seeds premixed by seed companies has led to almost universal use of high seeding rates of ryegrass (>20 kg/ha) which tend to suppress most other species including weeds but do not help the promotion of alternative herbage species. A lack of explanation of the growth habits, peak production periods, management requirements for optimum production and persistence, changes in quality between vegetative and reproductive growth etc. can hinder uptake of other species which may be better adapted for specific purposes than perennial ryegrass and white clover.
Clearly, opportunities exist for new pasture species to fill specific niches but current structures in rural industries require modification before successful adoption is likely.
High sugar grasses
Seed production in New Zealand
Most of the lucerne and annual clover seed (e.g. subterranean, balansa) is imported from Australia. In recent years seed supply of some annual clover seed has been compromised by Australian droughts and the reliability of seed supply for NZ farmers has been questioned. However, local production of seed from these species is problematic. For example, the technology for harvesting subterranean clover seed from burrs which mature below the soil surface needs further investigation. Strict import and biosecurity regulations mean new species introduction will only be permitted if it can be proved the species will not become invasive.
Initiating a New Zealand cultivar evaluation scheme to evaluate all new cultivars (both imported and locally bred) to test their suitability for local environments would be beneficial to the agricultural industry. Sociability of grasses with legumes and their persistence in grazed pastures should be essential for such a scheme.
Better integration of forages into farming systems
Improvements in seedbed preparation and establishment practices used by farmers and their contractors are likely to have the biggest impact on improving integration of forage crops into pastoral systems. Farmers who experience crop failures (see section 5) whether forage crops or alternative pasture species, are unlikely to invest capital into those species again as they are then perceived to be difficult to establish and have increased likelihood of failure.
New Zealand has well developed technologies for grazing lucerne with sheep and, to a lesser extent, cattle. The best advice for dryland farmers is that they should grow lucerne wherever conditions allow and should plant it on the best soils on their properties. Australia leads the world in annual clover research and there is opportunity for New Zealand farmers to adapt Australian technology to their local conditions. Improved management to increase the production of resident (>50 year old) cultivars of subterranean clover is currently being promoted. This in combination with the introduction of the best adapted modern cultivars and adoption of appropriate management strategies should enable dryland livestock farmers to at least maintain their current productivity if soil moisture regimes become more adverse.
The special feature of annual legumes over perennial legumes is their much faster growth rates in the cool season. Dryland farmers can exploit this annual legume productivity in late winter/spring (August to November) for ewe lactation. Twin lambs suckling from ewes grazing a pasture with 50% legume on offer can grow at 350-400 g/head/d before weaning at 90-100 days of age. Ideally all lambs should be sold from drought prone farms by the end of December. The basic technology for dryland pastoral farming is being applied by leading farmers and increasing drought experiences may hasten adoption rates of current best practice. Further advances are anticipated through the introduction of top flowering annual legumes from Australia to complement subterranean clover.
Current work in New Zealand with balansa and arrowleaf clovers suggests they may have a place in dryland pastoral systems. Gland clover (Trifolium glanduliferum) is an early flowering recent introduction which may also complement subterranean clover on sites with <500 mm effective rainfall (e.g. sunny north and northwest hill faces where evapotranspiration is extreme). Gland clover is one of the few annual legumes which is resistant to red legged earth mite (Halotydeus destructor). This major pest of annual legumes is likely to become more troublesome as conditions become warmer and drier.
Climate change predictions for a general increase in temperature will result in higher temperatures in high country regions and extend the perceived altitudinal limit to pastoral development. This limit is currently considered to be 900 m but improved pastures at higher altitudes may be viable in future. Perennial legumes such as Caucasian clover may have a role in such environments.
In conclusion, some of the issues and mitigation strategies discussed in this section are already standard practice for New Zealand’s “top” farmers. Nationally, the biggest shift in future productivity is likely to be achieved by uptake of existing “best practice” strategies by other farmers. This will require the advice and support of the entire agriculture industry (including research organizations, education providers, contractors, commercial field officers and extension staff) to transfer current knowledge onto farms. These practices will then be integrated into existing systems to maintain and enhance efficiency and ecologically sustainable pastoral agriculture.
|7. RESEARCH AND DEVELOPMENT ORGANIZATIONS
There are several Government and University based pastoral research programmes in New Zealand. The dominant crown research institute is AgResearch. In addition, Massey University in the North Island and Lincoln University in the South Island provide degree-based agricultural teaching and research.
Summary. AgResearch is a crown-owned research institute of approximately 1 000 staff, 650 of whom are research and development staff. Annual revenue is over NZ$ 150 M.
Their mission is focused around three complementary objectives:
Staff are mainly located on one of four campuses (Hamilton, Palmerston North, Lincoln and Invermay).
Summary of activities relevant to the dairy sector. The Dairy sector in New Zealand is served by several key research providers, including Fonterra’s own research units, DairyNZ, LIC and some universities. AgResearch seeks to complement these other institutes, not compete in most cases. Almost all activity within AgResearch is relevant to the dairy sector to some extent. A brief summary by section is shown in Table 14. In addition to these R&D capabilities, AgResearch has one dairy farm in the Waikato (at Ruakura), with another under development (at Tokanui) and one dairy farm in the Manawatu (at Flock House).
Strategic intent. AgResearch has developed a comprehensive strategic plan for improving the pastoral sector of New Zealand through research and development, called 2020 Science. The Dairy sector has a significant place in the strategic direction of AgResearch. Their current plans for research for the dairy industry are encapsulated in Goal 1 of the 2020 science implementation plans. The objective of Goal 1 is:
“by 2020, the net economic/export value of the NZ dairy sector will be doubled while halving (reducing) adverse environmental impacts (to acceptable international standards), through achieving productivity gains, sustainable intensification, reducing emissions to air and water, developing new, high-value products and enabling technologies and services (all compared to 2005 levels)”.
Partner organizations. AgResearch sections work with DairyNZ (in the areas of farm systems, forage and the environment), Fonterra (environment, forage development through its subsidiary Vialactia Biosciences), Massey University, LIC and many dairy processors (including Fonterra) in the development of processed dairy products. Investors include Pastoral21, FRST, DairyNZ and dairy companies.
DairyNZ Ltd, Hamilton
DairyNZ is the single dairy industry-good body owned by and operated on behalf of all of New Zealand’s dairy farmers. The organization is based at Newstead with two adjacent research farms. Other research staff are based in Northland, Taranaki and Canterbury, also with access to major research farm facilities.
The Science Programme is managed by;
Chief Scientist – Eric Hillerton (Email: Eric.firstname.lastname@example.org)
Leader of Animals Research - John Roche
Leader of Feed/Farm Systems Research - Dave Clark
The whole research team comprises 25 post-doctoral scientists and 75 technical, support and farm staff. More than 55 research projects are commissioned but the major effort is in 6 key areas. These are in;
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[The profile was drafted in the period March to September 2009 and edited by J.M. Suttie and S.G. Reynolds in October 2009].