The GRDC project ‘Maintaining profitable farming systems with retained stubble - upper Eyre Peninsula’ aims to produce sustainable management guidelines to control pests, weeds and diseases while retaining stubble to maintain or improve soil health, and reduce exposure to wind erosion. The major outcome to be achieved is increased knowledge and skills allowing farmers and advisers to improve farm profitability while retaining stubble in farming systems on upper Eyre Peninsula (EP).

The Minnipa Agricultural Centre S3S pasture trial was established in 2013 to assess barley grass weed management with a two year medic pasture break. The trial had different grass weed management and tillage treatments imposed in 2013 and in 2014. The trial was then sown with wheat in 2015.

Following two years of grass free medic pasture soil mineral nitrogen levels averaged 158 kg N/ha and all disease inoculum levels were low.

Cutting the medic pasture for hay lowered dry matter production and medic pod set in the following season.

An early light tickle resulted in higher weed germination and lower powdery mildew damage in spring.

Full cut tillage following two years of grass free medic resulted in the highest wheat yields while a discing prior to seeding resulted in the lowest yield.

Working medic residues in the year prior reduced the following wheat yield but grain protein was higher.

Cutting a medic pasture for hay in 2013 reduced medic productivity in 2014 and lowered wheat grain protein in 2015.