Pasture legumes and grasses for saline land in Western Australia

Page last updated: Friday, 15 May 2020 - 9:30am

The productivity of saline and waterlogged land can be markedly increased by using salt tolerant legumes and grasses, in mixtures. The mix is particularly important for increasing the productivity and profitability of saltbush-based pastures. The information is relevant to the south-west agricultural region of Western Australia.

The Department of Primary Industries and Regional Development provides this information on the tolerance and establishment of salt tolerant legumes and grasses to improve the productivity and profitability of saline land.

How salinity affects legumes and grasses

Salinity in the top 10 centimetres (cm) varies throughout the season – lowest in July to September, and highest in January to March (. Rainfall in winter flushes salt from the surface, down the soil profile, and evaporation in spring and summer causes salt to cncentrate on the surface. Soil salinity tends to stay more constant below a depth of about 25cm.

Consequences for annual plants

Annual plants on saline soils have a shorter growing season than those on adjacent non-saline soils. High salinities at the start of the growing season delay germination and can kill germinating seedlings of susceptible species. Plants adapted to saltland must either have a high tolerance to salinity during germination or ways to defer germination until later, when surface soil salinities are lower. In spring, high salinities can kill plants prematurely and reduce the time available for seed set.

Consequences for perennial plants

Saline soils increase the stress on perennial plants of summer drought. On saltland, perennial plants must either have mechanisms to cope with high salinity, or have some form of salinity avoidance mechanism, such as summer dormancy (e.g. puccinellia).

In general, plants use the freshest water available to them. Perennials, with their deeper root systems, can extract water from more of the soil profile than annuals. Tall wheatgrass, for example, avoids high surface salinity in summer by accessing less saline water from depth and then uses relatively fresh water closer to the surface during winter.

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Know your site

To select the best species for a particular paddock, you need to know:

  • your rainfall zone
  • EC1:5 measured across the site, at the relevant time and soil depth (see below)
  • potential for winter waterlogging
  • soil pH
  • soil texture.

See Measuring soil salinity for soil salinity classes.

Measuring soil salinity for annual pastures

High salinity on the soil surface during germination stresses self-regenerating annuals in the second and subsequent seasons. We recommend measuring the EC1:5 of the top 10cm over summer–autumn – the period of highest surface salinity – to find suitable soils for annual pastures. This may give an over-estimate of the salinity levels experienced by germinating seeds, but is a much better estimate than measurements taken in winter or early spring.

Measuring soil salinity for perennial pastures

Subsoil salinity in summer is the greatest stress to perennial plants on saltland. Measure soil samples from 25–50cm below the soil surface. This can be done in summer, or whenever the surface is dry.

Assessing waterlogging

Soils of high risk will be sodden for much of the winter, often with prolonged periods of surface water. Soils of moderate risk will remain sodden for up to two weeks after heavy rain, often with surface water visible. Soils of low risk will be free draining.

See Diagnosing waterlogging for more information.

Species selection for saltland

Do not attempt to plant pasture species on extremely saline land (EC1:5 range for loams >295mS/m). Fence these areas and allow natural regeneration of non-pasture species.

There are few salt tolerant legume options for low rainfall regions.

For soils classed as severely saline, messina is the only commercially available legume, and puccinellia and distichlis are the only available grasses.

Use mixtures of species

We recommend using a mixture of appropriate species, to cover the variability of salinity and waterlogging over short distances within paddocks. The best adapted species will colonise those parts of the landscape to which they are suited.

Tables of legume and grass tolerances

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Establishing salt tolerant pastures

Sowing and fertiliser rates, seeding depth, post-emergent weed and insect control and grazing management will be the same for these species as for establishment on non-saline land. The aim in the year of sowing should be to maximise the seed set of annuals and the ground cover of perennials to set up a long-term pasture.

To improve survival of seedlings on saline sites:

  • Control weeds and seed set in the year before establishment.
  • Cultivate hard surface soils to increase salt leaching.
  • Sow all species, apart from the sub-tropical grasses, soon after early season rains have flushed salt from the soil surface.
  • Sow sub-tropical grasses in late-winter or early spring, while the soil surface is still moist and temperatures are beginning to rise.
  • Control red legged earth mite.

Inoculate pasture legumes

For effective nodulation of legumes, inoculate seed with the strain of Rhizobium appropriate for the species, just before sowing. This is particularly important on saltland, as background rhizobia levels are likely to be very low or nonexistent, and rhizobia differ in their tolerance to saline conditions.

Weed control

Ideally, weeds should be controlled in the year prior to sowing to prevent seed set. In the planting season, there is often benefit from two knockdown herbicide applications (rotate herbicide groups): the first following an initial weed germination, and the second just prior to sowing. Many weeds (e.g. sea barley grass and ice plant) will have a delayed germination on saline sites (the delay will be longer on more highly affected sites).

Annual legume options (Table 1)

Table 1 Annual legume options (registered cultivars) for different categories of salinity, waterlogging, soil texture, soil pH and rainfall. Key: 1Other proprietary cultivars may be available that have not been tested. Note acronym: millimetres (mm)
Annual rainfall (mm) Salinity Waterlogging risk Texture pH (CaCl2) Suitable species Suitable species - cultivars1 Comments
275–325 Moderate–high Low Sandy loams–clay loams 5.2–8.5 Burr medic
(Medicago polymorpha)
Serena Less salt tolerant than Scimitar
275–350 Moderate Low Loams–clays 5.8–9.0 Barrel medic
(Medicago truncatula)
Caliph  
300–425 Moderate–high Low Sandy loams–clay loams 5.2–8.5 Burr medic
(Medicago polymorpha)
Scimitar, Santiago Scimitar is the best performing burr medic on saltland
325–500 Moderate Low Loams–clays 5.8–9.0 Snail medic
(Medicago scutellata)
Sava, Silver, Essex Seed may be hard to find
>350 Moderate-severe High Sandy loams-clays 5.5-9.0 Messina
(Melilotus siculus)
Neptune Needs salt-tolerant rhizobium
350–550 Moderate–high Low Sandy loams–clay loams 5.2–8.5 Burr medic
(Medicago polymorpha)
Cavalier  
350–550 Moderate Low Sandy loams–clays 4.8–8.0 Sphere medic
(Medicago sphaerocarpos)
Orion Little or no commercial seed
350–550 Low–moderate High Sandy loams–loams 4.5–8.0 Balansa clover
(Trifolium michelianum)
Frontier  
425–650 Low–moderate High Loams–clays 5.0–8.0 Persian clover
(Trifolium resupinatum)
Prolific, Nitro Plus  
450–700 Low–moderate High Sandy loams–loams 4.5–8.0 Balansa clover
(Trifolium michelianum)
Paradana  
>550 Moderate–high Low Loams–clays 4.5–8.0 Bokhara clover / White sweetclover
(Melilotus albus)
Jota High coumarin levels can cause haemorrhaging of stock if fed mouldy hay
>600 Low–moderate High Sandy loams–loams 4.5–8.0 Balansa clover
(Trifolium michelianum)
Bolta  
>650 Low–moderate High Loams–clays 5.0–8.0 Persian clover
(Trifolium resupinatum)
Kyambro  
>700 Low–moderate High Loams–clays 5.0–8.0

Persian clover / Shaftal clover
(Trifolium resupinatum)

Many cultivars One year fodder types

Temperate annual grass options (Table 2)

Table 2 Temperate annual grass options for different categories of salinity, waterlogging, soil texture, soil pH and rainfall. Note: 1Other proprietary cultivars may be available that have not been tested
Annual rainfall (mm) Salinity (see Table 1) Waterlogging risk Texture pH (CaCl2) Suitable species Suitable species - cultivars1 Comments
275–650 Low–moderate Low Sands–clays 5.0–8.0 Annual ryegrass
(Lolium rigidum)
Wimmera, Safeguard Safeguard has resistance to annual ryegrass toxicity
>550 Low–moderate Low Loams–clays 5.0–8.0 Italian ryegrass
(Lolium multiflorum)
Many cultivars  

Perennial legume options (Table 3)

Table 3 Perennial legume options for different categories of salinity, waterlogging, soil texture, soil pH and rainfall. Key: 1Other proprietary cultivars may be available that have not been tested
Annual rainfall (mm) Salinity (see Table 1) Waterlogging risk Texture pH (CaCl2) Suitable species - common name Suitable species - cultivars1 Comments
>400 Moderate Low Sands–clay loams 5.6–9.0 Lucerne
(Medicago sativa)
Many cultivars Winter active and highly winter-active cultivars perform best in WA
>550 Low–moderate High Sandy loams–clays 5.6–9.0 Strawberry clover
(Trifolium fragiferum)
O’Connors, Palestine  

Temperate perennial grass options (Table 4)

Table 4 Temperate perennial grass options for different categories of salinity, waterlogging, soil texture, soil pH and rainfall. Key: 1Other proprietary cultivars may be available that have not been tested
Annual rainfall (mm) Salinity (see Table 1) Waterlogging risk Texture pH (CaCl2) Suitable species - common name Suitable species - cultivars1 Comments
>400 High–severe High Sands–clays 5.5–9.0 Puccinellia
(Pucinellia ciliata)
Menemen Best suited to waterlogged, saline soils, dormant over summer
>400 High Moderate Sandy loams–clays 4.5–9.0 Tall wheat grass
Thinopyrum ponticum
Dundas, Tyrell Tolerates ECe levels >16 dS/m if it can access fresh water at depth, has weed potential in Victoria
>500 Low–moderate Moderate Sands–clays 4.3–8.5 Tall fescue
Festuca arundinaceae
Many cultivars Summer dormant cultivars perform best in WA
>550 Low–moderate Moderate Loams–clays 4.5–8.0 Phalaris
Phalaris tuberosa
Many cultivars Winter active cultivars perform best in WA

Sub-tropical perennial grass options (Table 5)

Table 5 Sub-tropical perennial grasses for different categories of salinity, waterlogging, soil texture, soil pH and rainfall. Key: 1Other proprietary cultivars may be available that have not been tested
Annual rainfall (mm) Salinity (see Table 1) Waterlogging risk Texture pH (CaCl2) Suitable species Suitable species - cultivars1 Comments
>350 High-severe High Sands–clays 5.5–8.0 Distichilis
Distichilis spicata
NyPa forage Only propagated by cuttings
>400 Low–moderate Low Sands–loams 5.5–8.0 Rhodes grass
Chloris gayana
Many cultivars Low frost tolerance, suited to northern and south coastal districts
>400 Moderate Moderate–high Sands–clays 3.7–7.0 Kikuyu
Pennisetum clandestinum
Whittet Performs poorly north of Perth

Contact information

Ed Barrett-Lennard
+61 (0)8 9368 3798