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SOLUTION 6

Puccinellia based pastures

 

6.5  Establishment & management of puccinellia based pastures

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Choosing the right species and varieties

The major decision for a puccinellia pasture is whether to make puccinellia the only species, whether to include a legume with the puccinellia, or whether to sow puccinellia as one component of a shot-gun mix. Oversowing puccinellia with a legume such as balansa clover or burr medic has been shown to be very successful in SGSL research in SA and has been copied by a few producers in the region but persistence of the clover is a real limitation. 

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Weed and pest control

Weeds

Weed control is the most critical factor underpinning successful establishment of puccinellia based pastures. Sea barleygrass is a major indicator species for where puccinellia will grow well and can tolerate the high levels of waterlogging often associated with ‘puccinellia suitable’ sites. Where puccinellia is established on sites where sea barley grass is present, it is essential that this weed be controlled, otherwise it will out-compete the small and relatively slow-growing puccinellia seedlings.

For controlling aggressive weeds such as sea barley grass, it is recommended that weeds are hit twice. A spray-top in the spring prior to the year of seeding is essential to reduce the weed seedbank in the autumn when puccinellia will be sown. In addition, a knockdown herbicide at the break of the season to remove the first germination of sea barleygrass (and any other weeds) will assist in reducing the competition faced by the emerging puccinellia. Other weed control options include burning and cultivation, or a combination of chemical and mechanical methods. The bottom line is that without thorough weed control, successful establishment of a puccinellia pasture is unlikely.

Once the puccinellia based pasture has been established, ensuring adequate phosphorus levels and periodic applications of nitrogen will also increase the competitive ability of the puccinellia pasture sward against invasion by sea barleygrass.

Sea barleygrass is very difficult to control in established puccinellia stands. Trials into the herbicide control of sea barleygrass in established puccinellia pastures have shown that the sea barleygrass can be removed, but the vacant spaces left after spray-topping the sea barleygrass were often filled by the less productive salt-tolerant weed, curly ryegrass, which itself is hard to get rid of. This highlights the importance of good weed control prior to the establishment of puccinellia based pastures.

Pests

Red legged earth mite (RLEM) can severely damage puccinellia seedlings, so monitoring and control of RLEM during establishment is important. The Timerite® program is an excellent tool for managing RLEM in the season prior to sowing.

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Site preparation

Pre-preparation

Grazing control is essential because newly established puccinellia plants are highly palatable so they are selectively grazed and are easily pulled out by sheep. Fencing also prevents sheep camping on the cooler salt-affected ground in summer. In some instances permanent fencing may not be appropriate (eg. if saltland occurs in small areas and/or is managed as part of a larger paddock). Temporary electric fencing may be an option. Alternatively it may be convenient to renovate or crop the higher ground in that paddock in the same year with stock excluded from the larger paddock.

If waterlogging is a problem that is likely to prevent effective access for pasture establishment (there is no problem with waterlogging once the puccinellia is established), shallow drains can be used to remove excess water. Diversion banks will reduce the movement of runoff water onto the area. Legal consideration and the disposal of any drainage water (and impacts to downstream biodiversity and landholders) should be considered prior to any drainage action.

Cultivation

Cultivate in early autumn (February/March, excepting sandy soils in low rainfall areas which should not be cultivated until after the break of season due to the risk of wind erosion), leaving a ridged or rough seedbed. A rough seedbed is particularly important for heavier soils or high salinities because:

  • it allows opening rains to leach accumulated salts out of the soil surface;   
  • it prevents opening rains flattening the soil surface and creating a surface seal which impedes plant emergence;    
  • it reduces the incidence of sand blasting which can destroy young establishing puccinellia plants;   
  • the slightly higher ground also provides a buffer against waterlogging and salt;  
  • it creates a range of niches in which surface seed can lodge.

On sandier or moderately saline ground a high level of ridging or roughness is less crucial, although it can be of benefit on non-wetting sands where seed and water accumulate in the depressions.

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Sowing

Sowing

The information in this website should be supplemented with local knowledge as this will be invaluable in getting the best results.

Seed should be dropped onto the soil surface, or sown at a very shallow depth. This can be done with a small seeds box or the seed can be mixed with superphosphate (up to 100kg/ha of superphosphate) just before seeding and sown through the fertiliser box.

Avoid harrowing, particularly on heavy soils or high salinity sites. Trial work has shown up to a threefold depression in dry matter production in the first year of establishment if the seed is covered using trailing harrows.

On clayey soils – leave rough to assist in leaching of salt.

On sandier soils – a light rolling post-seeding is beneficial for germination and establishment, through better seed-soil contact and moisture retention, but should be avoided where prolonged waterlogging is likely.

Again, seek local advice to see what has worked in your area.

Seeding rate

Sow at 4 to 10kg/ha. Use the higher rate when sown alone, particularly where salinity is more severe, or where the influx of weeds is likely to be an issue. As a general rule, denser pastures will yield higher productivity and so the higher seeding rates can produce a stronger stand. When sown in a pasture mix, 4kg/ha is a more usual rate.

From seed germination tests a small but significant percentage of seed may not germinate but can still be viable. This is classified as ‘fresh ungerminated seed’ and requires a period of extended flooding to germinate. Anecdotally, landholders in the Upper South East of SA consider fresh ungerminated seed an essential and valuable component of the seed bank because of its survival qualities. This seed survives through false breaks and can germinate after long flooding events.

Fertiliser at establishment

Soil phosphorus levels should be tested to determine baseline levels. Puccinellia will benefit from phosphorus applications if phosphorus levels are below the critical level of 12mg/kg (Colwell P). Soil extractable phosphorus levels above this are adequate for puccinellia. Phosphorus requirements will be higher (> 20mg/kg Colwell P) if there is an intention to sow balansa clover on the site. If balansa clover is sown and the Colwell P is below 20 the pasture will require regular P applications to maintain persistence and productivity.

Consideration should be given to the inclusion of companion legumes wherever site conditions (salinity and waterlogging) allow, to reduce the requirement for subsequent nitrogen fertilizer application.

Nitrogen can be applied at seeding time but higher applications may largely dissipate before the nitrogen can be used by the slow-germinating puccinellia. Plant emergence can take as long as 2 months on bare saline scalds. However, on more fertile sites nitrogen can boost growth and provide the advantage of earlier grazing.

Whenever nitrogen is applied, the timing and risk of waterlogging are critical to success. Nitrogen may be lost through the bacterially-mediated process of denitrification if waterlogging occurs soon after application. The use of MAP or DAP at seeding can be considered as a means of applying both nitrogen and phosphorus concurrently.

Economic analysis on small plots with high fertiliser prices during the SGSL program showed the nitrogen fertiliser was only marginally economic when applied to puccinellia based pastures. However, trials in the Upper South East showed that 25 kgN/ha applied as urea soon after the autumn break of the season increased puccinellia growth from 800 kgDM/ha to 1200 kgDM/ha, measured 4 weeks after application. At this time of the year feed production is at a premium.

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Timing of sowing:

General advice is to sow in autumn as soon as possible after the opening rains have stimulated the first germination of weed seeds at the site.

In addition, the opening rains will usually leach some of the accumulated salt out of the soil surface making the site more suitable for puccinellia seedlings. Where sea barleygrass is likely to be present, it is essential to wait for germination of the weed seeds then spray and sow the puccinellia. Timeliness is critical and can make a big difference to the success of pasture establishment.

If the site is likely to quickly become untrafficable after opening rains, dry sowing may need to be considered but in this situation, any weeds will emerge at the same time (or more quickly) than the puccinellia and out-compete the pasture. The general recommendation is for spray topping in the spring before sowing, but success with dry sowing can be improved by preventing weed seed set in the previous two springs so as to minimise the number of weed seeds available to germinate with the opening rains.

In higher rainfall areas (above 475 mm) sowing in late winter to early spring has given promising results but relies on good or extended subsequent spring rainfall to allow the germinating puccinellia sufficient time to reach sufficient size to survive the hostile summer conditions. In areas of lower rainfall, if opening rains have not come by early June, delay sowing until the next year. In most years, puccinellia sown after this time does not successfully establish.

Establishment downtime

Puccinellia seedlings are small, relatively slow-growing, highly palatable and susceptible to being pulled out by sheep. Therefore, it is best not set stock until the end of the second growth season after establishment (about 18 months) to allow plants to properly establish, particularly if a lower seeding rate has been used. While it is preferable not to graze during this establishment phase, careful strategic grazing may be possible. Seedlings of puccinellia look very fine and small, but stands will thicken in subsequent years if allowed to set further seed over the first summer. Where soil fertility is high and where higher seeding rates are used and/or pastures thicken up (and natural reseeding in the second year is less critical), early light grazing may be an option.

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Benefits from fertilisers and companion legumes

The application of fertiliser to puccinellia pastures is one of the key management strategies to increase productivity.

However, at moderate salinities, where legumes can be maintained, puccinellia will be receiving indirect nitrogen inputs from nitrogen fixing clovers or medics. In this case superphosphate is the appropriate fertiliser and is used to maintain clover nutrition. In situations where there is a strong stand of clover in conjunction with puccinellia, the nutritive value of both the green and dry feed is significantly boosted to the extent that the dry feed can support liveweight gain. However, there are currently no legumes that can withstand both high salinity and waterlogging so there is little opportunity for pasture legumes to contribute nitrogen to these systems.

If a saline site will support legumes (for example, balansa clover can tolerate significant waterlogging but only moderate salinity), or has nitrogen applied, the pasture and livestock benefits are significant, including:

  •  increased productivity from the puccinellia through the promotion of tillering and improved growth per tiller.
     
  • improved long term survival of puccinellia - the plants are stronger, more vigorous and able to tolerate higher levels of salt, flooding or waterlogging.
     
  • increased development of dormant tiller buds. These become tillers in the following year and this ‘sets’ the plant up for higher productivity.
     
  • increased feed quality. Digestibility is often increased but there is little effect on protein unless nitrogen has been applied above the growth demand of the plant.
     
  • increased seed production. This is a major consideration if the pasture it to be harvested for seed, or if thickening of the sward is needed.

Economic analyses from SGSL research indicates that nitrogen should be used strategically to fill feed gaps (e.g. early winter), rather than routinely as this is rarely economic. This is especially true in wool enterprises where the extra pasture and animal production do not always warrant the cost of nitrogen fertiliser and its application. The long term profitable productivity of puccinellia in these systems is dependent on there being some legume in the pasture to fix nitrogen to meet the nutritional demands of the grass.

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Timing of fertiliser application

Where legumes won’t persist, puccinellia dominant pastures will generally respond to nitrogen fertiliser, although the response will be limited if there are inadequate phosphorus levels in the soil. Puccinellia will benefit from phosphorus applications if extractable phosphorus is below the critical level of 12mg/kg (Colwell P). Requirements will be slightly higher if the site is capable of supporting clovers. In practice, few puccinellia stands have significant clover content and so many farmers now use N-P fertiliser blends annually on established puccinellia stands.

Fertiliser applications should be flexible and opportunistic. In established stands, nitrogen fertiliser can be applied at the break of season to boost autumn-early winter growth, while spring applications are undertaken to boost seed production or dry feed over summer-autumn. Whenever nitrogen is applied, the timing and risk of waterlogging are critical to success. In waterlogged soils, bacteria cause soil nitrogen to be converted back to atmospheric nitrogen through a process called denitrification. Therefore, nitrogen losses can be very high if waterlogging occurs soon after application.

The best rate and timing of nitrogen fertiliser application depends on annual rainfall, and seasonal feed requirements. There are a number of strategies that can be used.

  1. Late autumn – early winter (May to early June).
    Fertiliser is applied at the time of the opening rains (within a week or so). Being a perennial, puccinellia can shoot away rapidly following the opening rains and will respond rapidly to applied nitrogen while temperatures are still relatively warm and can support rapid plant growth.

    This is a very useful strategy to provide early feed or more grazing in winter and it allows other, annual pastures on non-saline land to ‘get away’ while the puccinellia is grazed. The risk with this strategy is that heavy follow up rain may lead to waterlogging and the loss of the applied nitrogen.

    From previous work in the upper south east of SA, application of nitrogen fertiliser in the late autumn – early winter period appears to give the best response economically, particularly for early winter feed. In a trial at Clover Ridge in the Upper South East, 25kg N/ha (50kg urea/ha) applied after the break of season (while conditions were still relatively warm) gave an additional 200kgDM/ha in 2 weeks and 400 kgDM/ha in 4 weeks. This was a 50% increase in pasture production over the period.
     
  2. Mid winter (July to early August).
    This is the most appropriate strategy for drier areas (< 400mm) that are unlikely to become excessively waterlogged over winter therefore risk heavy losses of nitrogen. In colder/wetter areas, this late application is rarely effective because soil temperatures are too low.
     
  3. Late winter – early spring (August to early September).
    This is a sound strategy to promote rapid growth in spring following grazing in winter, and to provide adequate ground cover or dry feed over summer-autumn. It is also an effective way to increase seed yield for harvesting.
     
  4. Split application in autumn and late winter.
    SGSL research has confirmed that this is the best option for maximal productivity, while anecdotal evidence suggests that seed production is also highly suited to this regime. The extra cost and time required to apply the fertiliser limits the widespread adoption of this strategy.

    If the economics of a livestock system do not justify a boost of fertiliser on an annual basis, timely nitrogen fertiliser applications could still be used to advantage every 2 to 4 years to enhance sward density and survival.
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Rates of nitrogen application

Optimal rates are related to rainfall and intended use of the pasture (Table 1). Higher rates are economical if the pasture is used for seed production.

Table 1. Suggested rates of nitrogen fertiliser for puccinellia pastures.

Rainfall (mm) 

350 

400 

450 

500 

Nitrogen (kg/ha) 

15 - 25 

20 - 30 

25 - 40 

30 - 50 

Urea (kg/ha) 

30 - 50 

40 - 60 

50 - 80 

60 - 100 

This table should be used as a guide only, as site and seasonal conditions influence fertiliser responses and make it difficult to provide generalised advice.

Fertiliser trials (in the Coorong districts and upper south east) indicated the most cost effective rate for early winter nitrogen application (a strategy to provide valuable early winter feed) was 25 kg N/ha (50 kg urea/ha). Previous work also found the most cost-effective rate for early spring applications, when nitrogen provides a boost to overall plant health and vigour (also helping stands compete better against sea barleygrass) was 12 kg N/ha (25 kg urea/ha). In contrast, SGSL trials at Mt Charles between 2003-2005 showed no significant responses in pasture growth below application rates of 25 kg N/ha.

The form of nitrogen applied (urea, ammonium nitrate, sulphate of ammonia, piggery effluent, MAP or DAP) appears to have little effect on overall response. Therefore the cheapest form, urea, is recommended. To avoid losses by volatilisation, urea should be applied to damp soil or just prior to rain. If this is not practical, apply urea late in the afternoon.

Rising fertiliser costs should also be factored in when making assessments of cost effective application rates.

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Grazing

Do not set stock until the end of the second growing season after establishment (about 18 months) to allow plants to properly establish, particularly if a lower seeding rate has been used. While it is preferable not to graze during this establishment phase, careful strategic grazing may be possible. Puccinellia seedlings are very fine and small but will thicken in subsequent years if allowed to set seed over the first summer. Where soil fertility is high and where higher seeding rates are used and/or pastures thicken up (and natural reseeding in the second year is less critical), early light grazing may be an option.

Puccinellia can be grazed in a number of ways depending on the characteristics of each site and pasture system, seasonal conditions and other feed available on the farm.

The greatest economic benefit is usually gained if puccinellia is used to fill the late summer-autumn feed gap reducing the reliance on expensive supplementary feeding. There is an additional benefit from carrying over the standing dry feed to be grazed dry in late summer-early autumn as it shades the soil, preventing the further build up of salinity through evaporation.

While feed quality declines as the plant goes to seed and hays off over the summer period, it still compares favourably with other dry pasture feeds through the summer-autumn period when feed is scarce. This standing dry feed is much more palatable than annual grasses or saltland alternatives such as tall wheat grass. However, some supplementation with hay may be required if weight loss needs to be avoided.

Puccinellia plants shoot vigorously following the opening rains, and provide the best feed quality through winter to late spring – often the time when it is most difficult to graze waterlogged paddocks where puccinellia is likely to thrive. Therefore, grazing puccinellia (as with other saltland pastures) requires management flexibility, particularly where the degree of waterlogging and/or inundation can be unpredictable.

Where winter inundation or flooding is likely, it might seem prudent to graze heavily before that time to maximise pasture utilisation while grazing is possible. However, puccinellia is able to survive inundation much better and for longer if the plant shoots are tall enough to remain above water. During this winter flooding, stock need to be able to graze higher ground, before moving back to the puccinellia pasture during the following summer-autumn period.

Puccinellia stands commonly support 5 dse/ha when averaged over the year. With appropriate management and fertilizer application, dry matter yields can be nearly doubled and stocking rates of 6-8 dse/ha supported. At these stocking rates liveweight gains of over 120 kg/ha and clean fleece weights of over 20 kg/ha can be produced.

Established puccinellia will tolerate hard grazing, but to maintain a vigorous stand, plants should be allowed to set seed at least once every two to three years – in many grazing systems this occurs every year with heavy grazing applied to the standing dry feed during the summer/autumn. Nitrogen applied at the break of season (or in spring, following winter grazing) also adds considerable vigour to puccinellia stands.

Unlike some saltland grasses (eg sea barleygrass), puccinellia seed is not damaging to animals and does not embed itself in wool, so puccinellia paddocks can be used as a weed-seed free zone during the ‘grass seed season’ for sheep meat and wool production. This strategy relies on the puccinellia pasture being well maintained and therefore sufficiently vigorous to prevent weed (especially sea barleygrass) invasion.

For more information, see Grazing balansa clover and puccinellia mixed pastures on saline land.

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Mixed pastures

Where companion legumes (such as balansa and strawberry clover or burr medic) can be established, puccinellia pastures will benefit from the nitrogen fixation, reducing the need for applying nitrogen fertiliser, as well as increasing the nutritive value for livestock.

Sowing pure puccinellia pastures (or puccinellia with companion legumes) is rare outside of the upper south east of SA. In most other regions, puccinellia is more likely to be part of a shotgun mix with tall wheatgrass, other less salt tolerant grasses (such as phalaris and tall fescue) and legumes (such as balansa and strawberry clovers and lucerne).

Saltland areas are often extremely variable and sowing a shotgun mixture allows the various species to colonise those areas most suitable. For example, typically puccinellia grows at the centre of the saltland area where salinity and waterlogging are highest; the zone for tall wheatgrass would be slightly less saline and less waterlogged (see photo in Section 6.2d), and the other species in the mix would establish best in the least saline, least waterlogged zones on the periphery of the saltland patch as well as on the surrounding, non-saline areas.

Grazing management of these mixed pastures can be problematic – for example puccinellia is best left standing during the heat of summer to protect the soil from evaporation and then grazed in late summer and autumn. If tall wheatgrass (a summer growing species) is managed in this way it will tend to become rank or clumpy and almost totally unpalatable. Slashing to avoid this unwanted growth in tall wheatgrass may be an option but is an added expense.

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Animal nutrition issues

Feed supplementation

The grazing value of puccinellia depends on its stage of growth. Green leaves in winter and spring have high protein content (15-25%) and high digestibility (60-75%), however this declines as the plant flowers and matures. It remains palatable in late summer and early autumn despite relatively low nutritive value (crude protein less than 5%, digestibility less than 50%). However, anecdotal evidence indicates that protein content in autumn is improved by longer durations of winter-spring flooding. This is conditional on plants not being fully submerged and water not stagnating during the extended flooding. Mineral analysis has shown that several important nutrients (particularly phosphorus) and trace elements (particularly copper) also decline sharply over the summer-autumn period. Hence feed supplementation with hay, lupins or grain, or grazing nearby lucerne, is often recommended to meet this seasonal shortfall in feed quality. Direct mineral supplementation can also be considered.

The best form of supplementation will depend on the particular feed value at the time of grazing and the type of stock. Lactating or growing animals require higher levels of metabolisable energy than other stock. During summer-autumn when puccinellia is low in protein and low in energy, lupins may be used to provide high protein and high energy. Extra hay may be sufficient for normal stock but usually won’t provide enough energy for growing or lactating stock. Supplementary feed options and particular stock requirements need to be assessed on a case by case basis.

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Integration into a farming system

The particular soil/climate situations that suit puccinellia based pastures best – moderately to highly saline and waterlogged – ensure that it is unlikely that puccinellia based pastures will be set stocked throughout the year. The most common times for heavy grazing of puccinellia based pastures are late autumn/early winter after the opening rains but before other, annual pastures have established sufficiently for grazing, and in late summer/early autumn when the dry, standing feed is grazed off.

The fact that livestock have to be moved on and off puccinellia pastures in this way means that integration of the puccinellia with the other feed resources on the farm is essential. There are both economic and practical considerations.

In How do the dollars stack up? whole farm economic modelling showed that it is much easier to incorporate puccinellia based pastures into a whole farm system if they contain a companion legume. In that case, whole farm profit per hectare of saltland pasture increased with each additional hectare. Without a companion legume, whole farm profit per hectare of saltland pasture declined with each additional hectare as it became more difficult to integrate the lower quality feed into the farm production system. Given that most puccinellia based pastures do not contain a significant legume component, the feeding options are more limited, and the need for supplementation is greater.

On the other hand, farmers report significant gains from integrating puccinellia based pastures into their farming systems, for example:

  • James Darling at ‘Duck Island’ in the Upper South East of South Australia runs a beef cattle breeding and fattening operation in a 450-500 mm rainfall zone. James says that the most important single factor in saltland agriculture is keeping a cover on saltland over the heat of the summer. After the 1981 floods, there could be no illusions about salt. The failure of all pasture species except areas of puccinellia underlined the urgency to use the plant to its best ability. ‘Duck Island’ would not have survived as a farming enterprise without puccinellia as it lengthens the season, providing predictable and quality cattle feed especially during the hardest season of autumn. Two thirds of ‘Duck Island’ becomes flooded in an average wet year so management has to be flexible and opportunistic. Not having a salt-tolerant legume to complement the puccinellia, James has also found a spring application of urea at 50 kg/ha useful, particularly for seed production. Properly managed, James expects to get 15 years from a puccinellia pasture before it needs renovation.
     
  • Gordon, Neville and Brian Stopp run a mixed enterprise (cropping, lucerne seed, wool and prime lamb) farm also in the Upper South East of SA. Despite the real management challenges, their 400 ha of saltland now fits very nicely into the whole farm system. ‘McNamara’ is chiefly a grazing block, with a combination of flats and hills where for much of the year the Stopps run their 3200 merino ewes with lambs and 1200 hoggets. Much of the higher country has been sown to lucerne, with primrose and veldt grass also used on the higher sand dunes, while puccinellia based pastures have been established on the saline flats. The Stopps are increasing the area under lucerne each year, as the plant is seen as highly valuable in stabilising sandy rises, reducing recharge and increasing productivity. The salty flats have been sown to puccinellia and the larger areas fenced off so that they can be managed separately. “Puccinellia has proved to be an excellent pasture for our sheep,” they are keen to point out. “It provides a nutritious seed-free environment for weaners before shearing in November and quality dry feed in autumn to extend the paddock rotation rest period when the lucerne is becoming less active.”
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Weed control

Weeds, particularly sea barleygrass and curly ryegrass, may become an issue in established stands of puccinellia. A farmer-initiated SGSL trial in the Coorong districts achieved some success in controlling sea barleygrass and curly ryegrass through spray-topping.

From the products tested, the best performing spray-top herbicides were found to be:

  • Paraquat (135 g/L) and Diquat (115 g/L) [Spray Seed ®] at 600 mL/ha, and
  • Paraquat (250 g/L) [Gramoxone ® /Nuquat ®] at *400 mL/ha, and *600 mL/ha.

*Results indicated a trade-off between the rate (which in turn relates to cost) and the duration of effective weed control, for these top performing herbicides.

In this trial, herbicides were applied from the early tillering to head formation and at the median soft dough stage for sea barleygrass.

While spray-topping of these weeds has proven successful, there is also a risk of curly ryegrass taking over the spaces left if the puccinellia pasture is not sufficiently robust to fill in the gaps. Curly ryegrass is a highly salt-tolerant plant that is very competitive on saline sites but it is even less productive than sea barleygrass. Ensuring adequate phosphorus levels and periodic applications of nitrogen are useful tools to promote the competitive ability of the puccinellia against these weeds, particularly when used in conjunction with chemical control.

Renovation

Established pastures that have large bare areas can be roughly cultivated using an implement such as a cultivator with every second tine removed. This will provide suitable areas to trap seed and allow germination, without killing the existing stand. Cultivate only where significant bare areas are present.

A single-tined ripper can also be used, especially along the edge of existing stands. Early autumn or late spring is the best time to undertake this operation.

Letting the puccinellia seed and mature, so that the seed drops, is another way to let the stand thicken up.

The prospects for puccinellia based pastures would be materially enhanced if a reliable saltland legume were to be developed, thus reducing the need for nitrogen fertiliser which is an increasingly expensive input, while at the same time significantly improving the nutritive value of the pasture. In fact, the prospects for almost all saltland pasture options would be similarly enhanced by the development of a more salt-tolerant legume for inclusion in saltland pasture mixtures. However the phosphorus requirement of legume species is higher than that of puccinellia so that regular inputs of P fertiliser will be rquired to maintain production and persistence of the legume component of the pasture.

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