EFFECTS OF SALINE IRRIGATION WATER ON SOYBEAN YIELD AND SOIL-SALINITYIN THE MURRUMBIDGEE VALLEY

The effect of saline irrigation water on soybean (Glycine max cv. Chaf fey) growth and yield is not known for southern Australia. Soybeans we re grown on hills, on a transitional red-brown earth, with moderately saline irrigation water (0.25, 0.5, 1.0, 1.5, 2.0 dS/m) for 2 seasons. Grain yield was significantly reduced when soybeans were irrigated us ing water with salinity >0.25 dS/m in the first year and >1.5 dS/m in the second year. The salinity of the upper 75 cm of the soil profile i ncreased with increasing salinity of applied treatments. Salinity leve ls at depth indicate increased flow beyond the root-zone with increasi ng salinity of applied water. The use of water >0.5 dS/m is not recomm ended for soybean cv. Chaffey on sites where soybeans have not previou sly been grown.