Water-Deficit Stress and Soil Type Effects on Spring Onion Growth

ABSTRACT Soil type and management practices can affect Allium growth and quality. This study investigated the effects of water-deficit stress and soil type on tissue water content, plant growth and dry-matter production of spring onion (Allium cepa L.) cv. White Lisbon. Seedlings were grown in a glasshouse in pots containing clay (Alluvial Gley) or sandy loam (Brown Earth). Irrigation treatments were watering to near field capacity (−0.01 MPa), or re-watering to near field capacity when the available soil moisture level was depleted to either ≤ 50% (−0.80 MPa) or ≤ 25% (−1.19 MPa). Watering to field capacity significantly (P < 0.05) increased relative water content and water potential of leaf tissue. Periodic water-deficit stress increased leaf number, but reduced leaf length. At −0.01 MPa, plant fresh weight and dry-matter content were increased, especially for plants grown on clay as compared with the −0.80 or −1.19 MPa treatments. Irrigation to near field capacity improved growth and dry-matter product...