Retaining soil water in farming systems using strip/disc machinery 2023

SA Drought Hub – Minnipa Node: Retaining soil water in farming systems using strip/disc machinery DN1_23_02

AIR EP, Buckleboo Farm Improvement Group and SARDI Minnipa Agricultural Centre 

Demonstration sites were established in low rainfall farming systems to determine:  

1. Can we measure increased stored soil water in strip/disc vs conventional no-till knife point systems? 
2. Are there other measurable benefits to the farming system such as soil cover, nutrition, weeds, disease, yield, soil health measures? 

2023 Demonstrations  

In 2023 three grower demonstration sites were set up with two different stubble systems, a stripper front stubble system using grower machinery and conventional harvest stubble implemented with the SARDI small plot harvester. The dates of the conventional stubble implementation were Cleve - Bammann 28 March, Buckleboo - Vandeleur 29 March and Minnipa - Oswald 6 April. Ideally the stubbles would have been set up at harvest in 2022, so that any differences in soil water and other measures over summer could have been quantified at the start of the 2023 growing season. 

Stubble cuts and stubble height were taken after the stubble treatments were implemented. Soil moisture measurements to 90 cm depth were taken pre-seeding. Spray cards to determine herbicide efficacy and spray coverage in different stubble systems were collected at seeding at Cleve and Buckleboo.  

The Cleve site at Bammann’s was sown on 18 April with a NDF SA650 single shoot low disturbance disc system with 24.1 cm row spacing. The paddock with different stubble systems was sown to Hurricane lentils and the stubble was then either rolled or unrolled.  

The Buckleboo site at Vandeleur’s was sown on the 4 May with Ballista wheat @ 60 kg/ha with MAP (monoammonium phosphate) @ 60 kg/ha using a 60 foot John Deere 1890 ProSeries Opener disc seeding system with 19 cm spacing, and the MAC conventional 25.5 cm Harrington point seeding system.  

Due to the later and dry seeding conditions (Decile 2) at Minnipa, Oswald’s decided not to sow the stripper and conventional stubble demonstration site with a cereal and instead the paddock become a self-regenerating medic pasture. Those project partners decided information relevant to low rainfall farming systems could still be collected with different stubble systems in the medic-based pasture. Half of the medic demonstration area has been fenced off to compare grazed and non-grazed stubble systems. 

Average stubble measurements in 2023 

Buckleboo (Vandeleur) plant emergence counts (average plants/m2) on 20 June 2023 

Stripper Disc Seeding System: 88.1 plants/m2

Conventional Seeding System: 94.2 plants/m2 

Minnipa (Oswald) medic plant emergence counts 10 July 2023  

 The spray cards to determine herbicide efficacy and spray coverage in different stubble systems were collected at seeding at Cleve and Buckleboo, but the spray coverage percentages still need to be processed as does the plant establishment data collected from Cleve (Bammann’s).