FutureDairy Project Leader Dr Yani Garcia said intercropping involved growing two crops in the same paddock at the same time.

“This could be an option for irrigated paddocks in regions where maize is harvested for silage in January and it is too early (too hot) to sow annual ryegrass,” he said.

“A cheap corn variety or old hybrid seed could be drilled immediately after harvesting the silage crop.

“Forage rape seed could be broadcast with fertiliser a few weeks later, when new maize is already up, to provide some protection for the brassica seed.”

The FutureDairy trials, conducted by research fellow, Dr Rafiq Islam, were sown in late February.

Maize intercropped with brassica in February can be grazed first in March when the maize is over 1.2m high; the maize will not re-grow but the forage rape continues growing during the whole autumn and winter period.

“Our trial yielded 15t dry matter/ha using just 1.5mgL of irrigation water, making it a very water efficient crop,” Dr Garcia said.

“We get better water use efficiency at that time of the year partly because evaporation is lower in the cooler months and partly because we had higher natural rainfall in winter.”

Maize and brassica out yielded other intercropping combinations such as maize/ryegrass and maize/Persian clover.

* Details: Associate Professor, Yani Garcia 02 93511621 or sgarcia@usyd.edu.au