EFFECT OF SALINE WATER COMBINED WITH RESTRICTED IRRIGATION ON PEACH-TREE GROWTH AND WATER-USE

The effect of four levels of saline irrigation (EC(i) of 0.1 dS m-1, 0.25 dS m-1, 0-5 dS m-1 and 1.0 dS m-1) in conjunction with restricted irrigation volumes was studied in drainage lysimeters over 2 years on peach trees (Prunus persica, L. Batsch), 3-years-old in Year 1. Strong negative linear responses to saline irrigation were measured for growth and final fruit size in Year 2. Leaf chloride increased over time and with treatment levels, reaching a maximum of 3.0% for the 1.0 dS m-1 treatment at harvest in Year 2. Root weighted soil Na and Cl levels increased with increasing irrigation salinity. Both Na and Cl levels in fruit and wood were increased by saline irrigation. Photosynthesis was reduced at the high EC(i) level consistent with decreased conductance and likely Cl toxicity. Saline irrigation reduced tree water use (TWU). Leaf chloride was determined to be a good indicator of salinity level and expected yield reduction. The need for leaching and modification of current Regulated Deficit Irrigation (RDI) management is proposed.