Grain sorghum is direct harvested for silage when grain in the middle of the head is in the dough stage.

Three broad groups of sorghums can be made into silage.

NSW Department of Primary Industries (DPI) district agronomist at Tocal, and NSW TopFodder Silage Coordinator, Neil Griffiths, said forage sorghums were best for grazing but could also be used for pit or baled silage.

"These hybrids must be grazed or harvested when young - for example, one metre tall - to achieve useful feed quality," he said.

"If allowed to bulk up and mature they will produce large yields of low quality forage.

"If made into silage, this low quality forage would be useful roughage in a drought, but would not support high levels of production."

Mr Griffiths said when making silage, these forage sorghums required a fast, effective wilt and good compaction to aid fermentation.

The next group are sweet sorghums, which can be direct harvested for chopped silage due to relatively high sugar content. Trial results show that they can produce very high yields per hectare, but again feed quality will be a limitation on potential animal production.

Grain sorghums are the third group to be trialled. Grain sorghums may be an alternative to maize for silage where conditions are unsuitable for maize.

"Grain sorghums are cheaper to sow and do not need the specialist machinery required for maize," Mr Griffiths said.

"They are quicker to mature, more tolerant of moisture stress and do not need the same high soil fertility."

As an example of the potential of grain sorghum in 2005/06, a trial of 28 grain sorghum hybrids at Tamworth had an average grain yield of 6.52 tonnes per hectare with the highest yield 7.16t/ha.

This same trial averaged 10.39 tonnes dry matter per hectare forage for silage with a top yield of 13.57tDM/ha.

Mr Griffiths said the top yielding hybrid had very good energy of 10.5 megajoules of metabolisable energy/kgDM, slightly below the trial average of 10.7 MJME/kgDM, which was as good as some maize silages.

For further information refer to www.topfodder.com.au or Topfodder Successful Silage book and DVD from the NSW DPI bookstore, on 1800 028 374.

Contact Neil Griffiths, Tocal, (02) 4939 8948, neil.griffiths@dpi.nsw.gov.au