Green technology for Mandurah roadside rehabilitation Seedballs are being spread on degraded soils to rehabilitate roadside verges in the centre of Mandurah. While this is technology dating from ancient Egypt it was rediscovered by Japanese natural farming pioneer Masanobu Fukuoka in the early 1940’s. He was looking to increase food production from rocky hillsides which were not suitable for traditional farming.
The original idea is to mix seed and soil together in a barely moist state and then roll into a ball shape, by hand. When dried the ball has a crust around the outside that protects the seeds. Ancient Egyptian farmers are thought to have made up seed filled balls to repair and replant farms after the annual Nile floods had inundated their growing fields.
John Barton senior scientist with C-Wise a locally based organic soil fertility company has developed the seed ball idea to incorporate a suite of local area native plants for the Main Roads Department. John developed a mechanical means of forming the balls which makes these more economic than the original hand made ones. A high humus mature compost together with a binding agent is incorporated into the ball so when the plant is ready to grow it is sitting in intimate contact with its own seed bed thats ready to supply food, biology and a moisture holding medium.
The first batch was delivered in April for the revegetation of a section of the Mandurah Entrance Road near the Gordon Road crossing. This area had been cleared for new underground services and needed to be replanted. Compared to direct seeding this technique has a number of advantages. The seed ball is designed to break down after sufficient rainfall has created a store of water in the soil to support the new seedling. Light rain can be a problem with direct seeding as it get germination started but then fails to deliver sufficient moisture to establish the plant. This means that with seed balls the timing of sowing is not as critical whereas direct seeding has to be done just before good rains for the best result.
Seeds in the ball are protected from seed eating insects and animals such as mice. You can mix various species together to get a more natural looking selection of plants. Sowing seed balls requires less horticultural skill. Its often possible to sow seed balls onto unprepared soil so this can result in lower costs of revegetation.
Another advantage is that seedballs can be thrown or blown into inaccessible areas. Their uneven surfaces help them stay where they land. This can reduce damage to slopes compared to standard sowing or planting methods. Main Roads are hoping that using seed balls will reduce planting costs and, more importantly improve success rates and the visual amenity of roadside verges. Of course this could have implications for rehabilitation techniques in other degraded areas on farms, in the bush and on mine sites. Steep slopes along the road verge were also included in this trial with the idea that plants offer the promise of natural erosion control as they spread out their roots to hold the soil.
Approximately a quarter of a hectare of land has been sown using seed balls. A range of low spreading shrubs and ground covers were used including native running postman, sheoak, wattle and native flag iris.
This is the first time seedballs have been used by Main Roads so all eyes will be on the experimental area to see if results are as good as hoped.
Hannah Gulliver setting up trial near Mandurah
Seed ball on soil
