Excess cation concentrations in shoots and roots of pasture species of importance in south-eastern Australia

Abstract

Excess cation concentrations (total cations – total inorganic anions) are reported for roots and shoots of 16 plant species of importance in pastures in south-eastern Australia. This information is required for the calculation of acidification in grazed pasture systems. The excess cation concentrations for shoots at flowering were [cmol(+)/kg]: perennial grasses — Lolium perenne (perennial ryegrass) 50, Phalaris aquatic (phalaris) 51, Danthonia richardsonii (wallaby grass) 30, Dactylus glomerata (cocksfoot) 62, Holcus lanatus (Fog grass) 60; annual grasses — Lolium rigidum 29, Vulpia bromoides (vulpia) 40, Hordeum leporinum (barley grass) 46, Bromus mollis (soft brome) 59; perennial legumes — Medicago sativa (lucerne) 115, Trifolium repens (white clover) 147; annual legumes — Trifolium subterraneum (subterranean clover) 142, Medicago truncatula (barrel medic) 114, Ornithopus sativus (serradella) 137; weeds — Arctotheca calendula (cape weed) 165, Echium plantagineum (Paterson’s curse) 169. Values for roots were in the same order as shoots in vulpia and wallaby grass but lower for the other species, varying between 26 and 62% of the shoot value in grasses and 29 and 49% in legumes. For a subset of 4 legumes and 3 grasses, the excess cation concentrations in shoots were measured over the main production period in spring. Excess cation concentrations generally declined during the season, with the change being relatively larger in grasses than legumes.