Two replicated field trials were established on the Eyre Peninsula in 2017. One on a red sandy loam, representative of typical Mallee environments in SE Australia (Minnipa Agricultural Centre Airport) and the other on a grey highly calcareous sandy soil (Brent Cronin’s property at Piednippie).

The 2017 medic trials were dry sown with inoculated Herald strand medic at 10 kg/ha, on 6 June (Minnipa) & 7 June (Piednippie). The GSR at Minnipa was only 155 mm, with most of that rain falling in July and August. All nutrition treatments (Table 1) were applied at sowing. Treatments to simulate herbicide residues were imposed immediately after sowing.

The early post emergent herbicide treatments were applied when the medic plants reached their third trifoliate leaf stage on 21 August (Minnipa) & 24 August (Piednippie). Due to the lack of early season rainfall and poor seasonal conditions this was much later on the cal

• 10 kg/ha Phosphorus (Phosphoric acid)
• 10 kg/ha Phosphorus + 100 ml/ha Tigrex (Phosphoric acid + 570 g/L MCPA as the ethylhexyl ester; 25 g/L Diflufenican) + 200 ml wetter
• 10 kg/ha Phosphorus + 250 ml/ha LVE Agritone (Phosphoric acid + 570 g/L MCPA as the 2-ethylhexyl ester) + 200 ml wetter
• 10 kg/ha Phosphorus + 200 ml/ha Agritone 750 Late (Phosphoric acid + 750 g/L MCPA as dimethylamine salt) 
• 2 kg/ha Zinc (Zinc Sulphate)

Residues

• 45 ml/ha Intervix (33 g/L Imazamox; 15 g/L Imazapyr)
• 1.75 g/ha Logran (750 g/kg Triasulfuron)
• 7.5 ml/ha Intervix (300 g/L Clopyralid as triisopropanolamine salt)

Post Emergent

• 100 ml/ha Tigrex Early (250 g/L MCPA as the ethylhexyl ester; 25 g/L Diflufenican) + 200 ml BS1000 wetter
• 100 ml/ha Tigrex Late (250 g/L MCPA as the ethylhexyl ester; 25 g/L Diflufenican) + 200 ml BS1000 wetter
• 250 ml/ha LVE Agritone Early (570 g/L MCPA as the 2-ethylhexyl ester) + 200 ml BS1000 wetter
• 250 ml/ha LVE Agritone Late (570 g/L MCPA as the 2-ethylhexyl ester) + 200 ml BS1000 wetter
• 200 ml/ha Agritone 750 Early (750 g/L MCPA as the dimethylamine salt)
• 200 ml/ha Agritone 750 Late (750 g/L MCPA as the dimethylamine salt)