Developing robust ground cover to enable resilience in low rainfall mixed farms

ABOUT THE PROJECT

We all know how beneficial groundcover is for improving rainfall infiltration, reducing runoff and lowering erosion risk. Retaining groundcover during drought means paddocks quickly regain production potential when the drought breaks and need less remediation than those that suffered erosion.

Ofcourse, maintaining drought resilient groundcover in low rainfall environments is always a challenge. In drier years there is simply less biomass to become protective stubble. More legumes in rotations have had many agronomic benefits such as building soil nitrogen and disease control, but means limited stubble after harvest.

It’s tough, but there are more options on the horizon to help farmers keep groundcover in dry periods.

Since 2021, six projects have been underway that explore practices and technologies to maximise groundcover in the system year- round. Supported through $2.5 million in funding from the Australian Government Future Drought Fund, the projects cover a range of strategies that improve crop establishment and reduce stubble disturbance and degradation at multiple points throughout the season:

These projects were chosen because the technology is either already in use in other regions (and needs assessing and adapting to suit low rainfall environments) or is close to market.

RESOURCES

SEED PRIMING

Seed priming – soaking the seed before sowing – aims to initiate the early stages of germination. The process reduces the amount of moisture needed to complete germination, meaning that seeds: can germinate faster and more uniformly once sown can germinate in lower soil moisture than normal and show greater vigour might establish better in non-wetting soil. On the sandy, non-wetting soils, seed priming could help establish more vigorous groundcover in drier seasons and provide an increased yield potential.

LONG COLEOPTILE WHEAT

Long coleoptile wheat varieties could give growers an opportunity to establish a crop when the weather isn’t cooperating. Wheat varieties with long coleoptiles can germinate from deeper in the soil than their conventional counterparts. By sowing deeper into residual summer moisture, crops can access water immediately. In dry years with limited autumn rain, this could mean the difference between having a crop or not. Other benefits include: sowing beneath a non-wetting soil layer (see ‘Grower experience’ at the end of this article) better crop emergence when seeding depth is harder to control, such as after mechanical soil amelioration seeding deeper to avoid pre-emergent herbicides ensuring timely establishment regardless of the seasonal break by accessing subsurface moisture, such that growers are confident that their wheat crops will hit their environment’s optimal flowering period and maximise yield.

STRIP AND DISC SYSTEMS

‘Strip and disc’ systems – a stripper front harvester and disc seeder - are already used successfully in higher rainfall regions. The system is favoured as a way to conserve stubble. The stripper front harvester ‘picks’ the heads off the wheat, leaving tall standing stubble. Because it is not in contact with the soil the stubble lasts longer, providing better erosion control, shading and cooling the soil surface, and making conditions more favourable for the emerging crop. However, because of the long stubble, disc seeders rather than conventional tyned seeders are required to sow through the stubble.

VIRTUAL FENCING

Growers are looking forward to the opportunity to move fences without leaving the house. Virtual fencing has been in development for over a decade and more recently paddock trials on crop-livestock mixed farms have been underway in South Australia, New South Wales and Victoria. Many farmers see the technology as a potential game changer for paddock grazing and groundcover management. Growers can easily move virtual fences around paddocks using the software on their computer or phone to: ensure no one area becomes too heavily grazed (or undergrazed) keep cattle off vulnerable soil types and erodible or waterlogged areas better control grazing pressure to maintain optimal groundcover

SOIL AMELIORATION OPTIONS

Strip amelioration is a concept that allows growers to ameliorate paddocks in stages while maintaining functional groundcover. Strip amelioration works a portion of the paddock by leaving alternating strips of ameliorated soil and undisturbed standing stubble. The machines are modified to work in narrow strips, which keeps the ameliorated soil better protected by close surrounding standing stubble. With lower erosion risk, the amelioration window can be wider, giving growers more flexibility in fitting soil amelioration into the calendar. The project is also evaluating simultaneous strip-sowing (sowing the ameliorated strips only), which aims to not disturb the standing stubble strips, leaving better protection than uprooted or knocked down stubble by blanket sowing.