Abstract:
The introduction of watertable control by groundwater pumping on a salt-affected dairy farm in the Goulburn Valley resulted in large increases in butter fat production. Since intensive pumping started, in 1981, watertable levels showed an overall downward trend but were still subject to major fluctuations caused by irrigation and rainfall. During this period butterfat production increased from about 300 to 390 kg/ha (of productive land) and yearly pasture production rose from about 560 to 650 t/ha DM. These productivity increases are attributed to both a reduction in average soil salinity in the top 60 cm of the profile from 2400 to 1200 mg total dissolved salts per kg dry soil and an increase in irrigation water use from less than 10 M litre/ha before to nearly 12 M litre/ha after pumping started.