Key points

• Precision planting improved the uniformity of winter crop stands and often allowed reductions in plant density without loss of yield
• Although yield gains from precision planting have been variable, potential benefits will be greatest in crops with high seed input costs
• Growers should consider the most cost-effective way in which to transition to more precise sowing equipment

In an effort to reduce the cost of hybrid canola seed – but also to maximise productivity in other winter crops – precision planting technology is gaining interest in the southern and western regions.

Particular interest is focusing on seed singulation technology, which is the ability to precisely locate a single seed in the seeding row. By placing seed at consistent depth and distance apart, uniform emergence can be achieved, reducing plant competition and maximising growth and yield per plant.

In 2018 and 2019 GRDC invested in a multi-pronged project, managed by the University of Adelaide, to survey crops in the southern and western regions to assess variation in seedling emergence and seedling depth and to examine what factors contribute to this variation.

The team also undertook a series of small-scale and large-scale trials comparing conventional sowing – either a cone seeder or an airseeder – with precision planting, and carried out a qualitative survey of users of precision planters for winter grain crops (see breakout box for growers’ tips).

Paddock survey findings

The survey highlighted the variation in crop establishment that occurs within a paddock and between paddocks. Crop establishment in canola and lentil crops was found to be variable and improvements were foreseen in many cases which could improve establishment and reduce seed costs. Establishment was lower and more sensitive to sowing conditions in canola than lentils and provided greater scope for improvement.

The survey highlighted that the age and make of a seeder was less important than knowing a seeder and the factors that affect establishment, such as seeder set-up, calibration, sowing speed and depth.

A consistent feature among growers who achieved good rates of crop establishment was their attention to detail in setting up the seeder, making adjustments according to sowing conditions and monitoring performance during seeding.

The survey found that establishment of canola and lentils is influenced by different factors. While some factors are outside grower control, there were simple changes that could maximise establishment.

Establishment in canola was lower with early (April to early May) sowing, which was associated with many crops being dry-sown or with low soil moisture during the dry autumn in 2019. Establishment in lentils, however, was not affected by time of sowing.

Establishment was greater with hybrid canola varieties than with open-pollinated varieties and also tended to be better when seed and fertiliser were separated during seeding.

Maintaining good surface structure to minimise crusting was found to assist seedling emergence and this could be achieved, for example, through stubble retention or management of sodicity.

Trial results

A series of small plot trials were conducted between 2018 and 2020 in South Australia and Victoria using a purpose-built six-row seeder that could sow seeds as a conventional cone seeder or as a precision planter.

The precision planting units were commercial row units supplied by Spot on Ag, in Boort, Victoria. A trial at Merredin in 2019 used a small plot seeder operated by the Western Australian Department of Primary Industries and Regional Development with the capacity for singulation as well as conventional sowing.

Both plot seeders used disc seeding systems, except in 2018 when cone seeding could only be done with a tyned seeding system.

Large-scale trials were also conducted with canola and faba beans near Skipton in western Victoria using a Väderstad airseeder (Seed Hawk model in 2018; Rapid model in 2019) and a Väderstad precision planter (Tempo). Each trial compared the responses to row spacing (25 centimetres versus 50cm) and sowing rate (recommended versus half-recommended) and were sown in plots 150 metres long.

In most of the plot trials there was no significant difference in the yields between the two seeders, with significant differences being measured in two of the nine trials; in both cases precision planting improved yields.

Crop establishment in the pulses was generally higher than in canola, but for both plant species there was no consistent effect of precision planting on establishment, while crop uniformity was improved substantially with precision planting. When there were differences in yield, precision planting improved grain yield by 18 per cent and 22 per cent for faba beans, 10 per cent for lupins and 14 per cent for lentils. In a number of cases, precision planting achieved equivalent yields to conventional planting but with a lower plant population.

The results for canola and pulses indicated that despite variable effects on establishment, precision planting resulted in yields equivalent to or higher than those achieved with conventional sowing and sometimes at lower plant populations.

The potential economic benefit of this is the saving on seed costs from producing the same yield with fewer plants per square metre. However, the responses to precision planting varied among experiments and the factors influencing the yield benefits from precision planting are still unclear.

Sourcing precision equipment

Precise and smart seeding technology is evolving rapidly, with airseeder-based transitional options becoming available that could allow a more practical and cost-effective pathway to greater planting precision.

A list of suppliers and support for precision planting technologies is given in the table.

* This is an extensive list to the best of the author’s knowledge; please consult your local retailer for more information.

Checklist for adopting and operating precision planters:

• Precision planting = precision placement first and seed singulation second (the benefits of seed singulation are not realised unless accurate seed placement can be delivered, through technology features, settings and operation, and including low paddock roughness).
• Plan the shift to precision planting, and address soil constraints, paddock preparation, seed grading/cleaning/quality, residue, weed management and logistics.
• Do some homework; research, talk to users and manufacturers, and look internationally for up‐to‐date information.
• Ensure technical support is available with the choice of technology or be ready to struggle.
• Be confident in your choice of planter or delay selection until you are confident.
• Hi‐tech planters might not imply higher cost‐effectiveness.
• Use clean seeds, graded and of high quality.
• Keep an eye on performance, monitor regularly, be conscious of speed.
• Precision planting of larger seeds is less challenging when starting.

More information: Glenn McDonald, 08 8313 7358, glenn.mcdonald@adelaide.edu.au