Raised beds exemplify on-farm adaptation
GroundCover™ Issue: 117 | Author: Clarisa Collis
Australia famously rode to prosperity on the sheep’s back, but it was the decline in wool as the nation’s main rural export that led to more profitable, risk-averse farming systems in the high-rainfall zone (HRZ).
One consequence was major expansion in high-rainfall cropping about 20 years ago, aided by water-management innovations such as raised beds.
Raised-bed cropping pioneer Bruce Wilson says the land-forming tactic to help overcome waterlogging on heavy clay soils during the long, cool growing season was pivotal to the HRZ grains expansion.
Bruce, whose family farms at Winchelsea, 115 kilometres south-west of Melbourne, says the transition to two-metre-wide raised beds on their property in 1997 lifted grain yields by up to 50 per cent. This allowed them to progressively expand their mixed farming operation from 1000 to 5000 hectares.
Parallel to this growth in the Wilson farm business, raised-bed cropping across Victoria’s south-west increased from 3000ha in 1997 to about 35,000ha in 2003.
Further expansion was interrupted by dry conditions at the start of the millennium, but a return to wetter seasons in recent years has seen a resurgence in new 2 and 3m raised beds and the renovation of old beds.
The Wilsons are a case study in adaptability – moving in and out of raised-bed cropping as seasonal and soil-quality needs dictate.
“In 2014, we created raised beds on another 100ha, mostly to improve soil structure,” Bruce says, adding that raised beds now cover about 1500ha of their 3000ha grains program.
He says another benefit of the raised-bed revolution on their grey vertisol soils, and in the HRZ generally, is that it has lent itself to new best-practice farming methods. For the Wilsons, these include controlled-traffic farming (CTF), minimum tillage and stubble retention.
Bruce says such beneficial strategies linked to the implementation of raised beds have posed new challenges that have also driven adaptation and innovation in farm machinery design. For example, 2m raised beds encourage the principles of CTF across the family’s paddocks because machinery wheels are confined to the furrows separating the beds.
The result is reduced soil compaction that improves soil properties. In addition to increasing yield potential, better soil has resulted in faster vegetative growth that leads to heavy stubble loads.
Bruce says sowing into large stubble loads with discs is not an option on their grey clay soils, so in the past they resorted to burning despite their preference for stubble retention.
Now an ingenious advance in on-farm machinery development has helped the Wilsons to overcome not only the problem of high stubble loads, but also raised-bed renovation, slug control and subsoil manuring.
This development is a custom-made K-Line Agriculture machine featuring discs to cut the stubble and work the soil, furrowers to form the beds and a roller that flattens the raised bed surface and crushes slugs.
“Hydraulics on the furrowers mean they can be disengaged and lifted out of the way, so the machine can be used to incorporate stubble and our mix of pig manure, lime and gypsum as well,” Bruce says. “Plus it can be used on our bedless canola country.”
Investing about $140,000 in the machine, Bruce thinks they might recoup this expenditure in less than two years.
This projection is based on his estimate that its multi-functioning benefits have the potential to lift the profitability of their grain crops by about $100/ha.
More information:Bruce Wilson,
0417 587 387, 03 5267 2381,