The effect of NaCl on the establishment and growth of balansa clover (Trifolium michelianum Savi var. balansae Boiss.)

Abstract

The effect of NaCl on the germination, seedling emergence and growth of established plants of balansa clover, Trifolium michelianum Savi var. balansae Bois. cv. Paradana was studied and compared with plants of subterranean clover T: subterraneum L. cv. Clare. Balansa and subterranean clover had similar salt tolerances at germination and seedling emergence. However balansa clover suffered from poor seedling vigour even under non-saline conditions, and this resulted in a low number of emerged seedlings over all NaCl concentrations compared with subterranean clover. Established plants of balansa clover, despite a lower initial seedling yield, were significantly more salt tolerant (P < 0.001) and had a greater survival rate over a four month period at concentrations greater than 75 mol m-3 NaCl. Shoot concentrations of chloride and sodium increased with increasing salinity in both species, however concentrations were lower in balansa clover especially at higher NaCl concentrations (75 and 100 mol m-3 NaCl). It is concluded that whilst established stands of balansa clover may be able to withstand high concentrations of NaCl, the major limitation to its establishment and production in saline irrigation areas is its poor seedling emergence and vigour.