Perennial pasture production after irrigation with saline ground water in the Goulburn Valley, Victoria

Abstract

Irrigation water with nominal salinities of 100,300,700,1500 or 3000 mg/litre and superimposed yearly gypsum treatment (5 t/ha) were applied for 2 years on established white clover, ryegrass and paspalum pasture grown on a red-brown earth soil type, and for another 6 years after the pasture was sod-seeded with strawberry clover. Initially pasture dry matter production was reduced at all salinities above the control, predominantly because of a decline in white clover growth. However, after strawberry clover was added to the sward, pasture yield was not significantly affected by water with salinities up to 700 mg/litre in any one year and only reduced by about 25 and 50% at 1500 and 3000 mg/litre respectively. Soil salinities had largely reached equilibrium after 4 years and relative pasture yields remained relatively stable from then to the end of the experiment and it is not expected to change greatly in the longer term. Pasture mineral composition was within the recommended range for animal diet requirements.