Twin sowing is a promising new technique of establishing self-sustaining crop-pasture rotations in a single pass operation, which eliminates competition for moisture between the crop and pasture.

A range of annual pasture legumes have the potential to be used in twin sowing systems for the establishment of self-sustaining crop-pasture rotations.

“A recent survey of 300 farmers highlighted many producers were dissatisfied with the performance and lack of flexibility of their current pasture system,” said NSW DPI research agronomist, Belinda Hackney.

With increasing farm input costs they wanted lower pasture establishment costs, more robust pasture legumes, alternative sources of nitrogen for cropping systems and greater options for fodder conservation.

Mrs Hackney says under climate change predictions these needs will only increase.

Twin sowing overcomes some of the limitations of cover cropping.

The system was developed in Western Australia by Angelo Loi and Brad Nutt and is currently under evaluation in NSW as part of a Pastures Australia funded project.

Unscarified hard seed (or in the case of serradellas, seed encased in pod) is sown with a crop.

“The seed of annual legumes is very hard and therefore does not germinate in the year of sowing,” Mrs Hackney said.

“Because there is little legume germination in year one, there is no need to cut back on the normal crop sowing rate.”

The legume seed softens in year one and then germinates and emerges in year two, which is a pasture year.

The pasture grows, fixes nitrogen and sets seed in year two.

As seed set by the annual legumes is almost all hard, it is essential to crop again in year three to allow the legume seed to soften.

The crop grown in year three uses the nitrogen fixed by the legume in year two and therefore reduces the need for fertiliser nitrogen.

This type of crop-pasture rotation can then continue with pasture followed by crop without the cost of re-establishing pasture.

NSW DPI will be establishing small plots trials and larger farmer scale sowings to evaluate twin sowing over the next few years.

Contact Belinda Hackney, (02) 6938 1999, or Nigel Phillips, 0427 102 707.