Likely situations for temperate perennial grasses

 

1.     Salinity and waterlogging
Phalaris seems to be slightly more salt-tolerant than tall fescue but there is not a big difference – neither will be productive if soil salinity (ECe) exceeds about 6-8 dS/m and both are better suited to soils with salinity levels of about 4 dS/m. As a general rule, waterlogging and salinity have additive effects on plant growth, so as the waterlogging at a particular site increases, the salinity levels that phalaris and tall fescue can tolerate will decline.

As salinity and/or waterlogging at a site increases, the suitability of phalaris and tall fescue quickly diminishes, and tall wheatgrass and puccinellia become more productive and persistent options.

Most likely situations for the temperate perennial grasses phalaris and tall fescue

Subsoil salinity/ depth to watertable matrix

 Winter

Summer 

 

 

Drivers of plant zonation

  • Non-halophytes so very limited salinity tolerance;
  • Some tolerance to waterlogging in winter
  • Summer growth assisted if access to low salinity groundwater
  • 400mm during the growing season

 


Key to symbols

red dot

This is the zone most preferred by saltbush and where it is highly recommended;

Small Dot

Saltbush is one of the possible options for this zone but it is outside its preferred conditions;


2.     Climate and soils
The suitable range for phalaris is areas receiving more than 300 mm of effective rain between April and October. Tall fescue is less drought-tolerant than phalaris, so in general, better soil moisture conditions are needed – either from better soils, higher rainfall, or higher altitudes where evaporative demand is lower.

Phalaris and tall fescue can adapt to a wide range of soils, however, they grow best on deep, heavy textured soils with good water holding capacity and high fertility. Fertile soils will promote good clover growth which will meet their high nitrogen requirements. Performance at soil pH levels less than 4.5 (in CaCl2) will be poor.

3.     Indicator species
The ‘classical’ indicator species for saline land (such as sea barleygrass, marine couch or saltwater couch, water buttons etc) all tend to indicate levels of salinity and/or waterlogging that will exceed the tolerance of the temperate grasses - though land suitable for phalaris or tall fescue may be in abundance towards the edges of the saline site and surrounding it.

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