Improving the value & sustainability of Esperance port zone grain growers.

Gavin and Elaine Egan

Amelioration program thwarted by rain requires innovative seeding techniques

When Gavin and Elaine Egan decided to cut their annual January beach holiday short to return to their Scaddan farm and go delving, they thought they were making a sensible and rational decision.

The plan had been to increase the rooting depth of their crops and reduce the severity of the non-wetting topsoil by breaking up the clay layer beneath and bringing chunks of clay up to the surface. From there a spader would be used to mix the clay through the top soil creating a better seeding bed and further assisting with stubble incorporation.

What they hadn’t planned on was that by April, more than 250mm of rain would leave the delved paddocks un-trafficable and they would be unable to incorporate the clay over summer.

Not only were their paddocks un-trafficable following the delving, but as they dried out again, hard crusts had formed in the areas where the largest chunks of clay had been brought to the surface. Across their paddocks the soils are highly variable and range in terms of the depth to clay and the type of clay in the B horizon. These differences greatly altered how the soil was left and what the best approach would be moving forward.

Fortunately the Egans have been using Variable Rate Technology (VRT) (for phosphorus, nitrogen, gypsum, lime and potash applications) for a number of years and this meant that the paddocks had already been soundly soil tested and mapped into different soil zones. The zones allowed them to tackle their latest predicament in a logical way. For some areas it was possible to still spade the soils and then conventionally seed but for others a more innovative approach was required. A spader with an air seeder perched on the front allowed the trickier regions to be spaded and aerially seeded in one pass.

Bucket loads of innovation and patience has been needed to get them through their prolonged seeding program. They joke that a giant 20m snatch strap from Farm and General has been one of their most worthwhile investments so far this year. However once finished Gavin is hopeful that the efforts of ameliorating these soils will in the future provide the 25% plus yield increase he has experienced in earlier programs.

With good seasons and higher yields, stubble and trash management have required a bit more thought. How do you retain the biological benefits from trash without the headaches at seeding? Gavin has sought to incorporate high stubble loads using strategic tillage. This in combination with gypsum and lime on selected soil types has seen a proliferation of biological activity in the form of earthworms (and yes one or two snails). Although lime is not recommended on alkaline soils, Gavin is adamant that the combination of lime and gypsum has further benefitted productivity.

Through several years of development the Egans have optimized this soil management approach for their shallow duplex soils and through the knowledge gained they have been able to adapt this system to work despite the a-typical rain event experienced by Esperance farmers this summer. However Gavin believes there is still much more he wants to learn about soil management. In order to continue to optimise his system he is interested to further investigate: which soils can be delved; how nutrition requirements may change post delving; and how best to improve the soil biology.

DAFWA’s David Hall and Tom Edwards plan to further investigate these issues in coming years through their GRDC funded soil constraints programs. Working with farmers like Gavin and Elaine, David and Tom hope to better understand what farmers are finding is working and then help them to validate their new systems.
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Photo: Elaine and Gavin Egan with the Delver used to break clay and bring it to the surface on their Scaddan property.

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