Effects of saline irrigation water on soybean yield and soil salinity in the Murrumbidgee Valley

Abstract

The effect of saline irrigation water on soybean (Glycine max cv. Chaffey) growth and yield is not known for southern Australia. Soybeans were 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 using 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 increased with increasing salinity of applied treatments. Salinity levels at depth indicate increased flow beyond the rootzone with increasing salinity of applied water. The use of water >0.5 dS/m is not recommended for soybean cv. Chaffey on sites where soybeans have not previously been grown.