Lucerne could return to star as the dominant pasture crop in the Great Southern farming area of W A as graingrowers look for new ways to overcome waterlogging problems and declining protein levels.
According to University of Western Australia researcher Lisa Blacklow, deep-rooted perennial lucerne offers graingrowers major benefits in reducing waterlogging and erosion. These benefits are not available with annual species such as subclover.
"Rain falling outside the growing season is a major cause of waterlogging and salinity in W A and our trials are showing that lucerne can help use out-of-season rain before it seeps into the subsoil," she said. She cited the experience of growers in southern N SW who have added lucerne to their cropping rotations and are reaping the benefits of less waterlogging and added nitrogen for following crops. Trials on Geoff Bee's Jerramungup property have shown rapidly falling water tables under paddocks sown to lucerne. Further trials are being conducted on Bronte Rundle's farm near Katanning.
Miss Blacklow acknowledged that W A growers have been reluctant to plant lucerne since the widespread devastation in the 1970s when pastures were wiped out by lucerne fleas and blue green aphids.
However, new insect-tolerant varieties have changed the situation. Common pasture insects can still attack lucerne stands and growers must control these throughout the season, she said.
Early results show:
- lucerne establishes well with shallow sowing (1 cm)
- lucerne grows best without competition from a cover crop
- addition of nitrogen fertiliser gives no advantage.