Ground Cover North : Ground Cover 051 August-September 2004 - North
Research and development for growing grain crops on beds, whether raised or flat, began in 1996 with a drainage demonstration site established by Southern Farming Systems (SFS) at Gnarwarre near Geelong. The aim of this farmer-led group was to improve drainage and at the same time enhance soil structure. The narrow (1.5 metre) raised beds showed an instant drainage benefit (60 percent yield increase with canola) and after only two crops, significant soil structure improvements were measured. Soil structure parameters that improved included slaking, dispersion, water infiltration and bulk density. In 1997, SFS commercially trialled raised beds and controlled traffic over 300 hectares on eight properties. Due to the desire to fit in with existing equipment owned by the volunteer farmers, bed widths ranged from 1.7m to 2.16m. Only two of the eight paddocks experienced waterlogging rain. However yields increased in both wet and dry paddocks, prompting a large number of farmers to give the concept a try. Geelong machinery manufacturer Rex Watson and Toowoomba machinery manufacturer Gessner developed a robust bedding machine able to handle rocky and heavy clay volcanic soils. Raised bed farming then began in earnest. In 1998 about 7000 hectares were installed and high yields were achieved even though conditions were generally dry again. However, isolated wet conditions did occur and the benefits of the raised beds in alleviating waterlogging were clearly demonstrated. The concept has continued to gain acceptance at a steady pace and today there are about 35,000 hectares in Victoria. Reasons for this quick adoption are varied but include: n SFS's low research and development budget necessitated the development of practical, cheap solutions to bed management; n machinery manufacturers, dealers and contractors enthusiastically hopped on board; n positive peer group sentiment; n SFS provided up-to-date research and development; n continued positive response whenever waterlogging conditions occurred; and n farmers developed the technique themselves in partnership with researchers. To tackle the many unknowns about large areas of raised beds, SFS established two concept farms, each covering about 200 hectares. The land was cleared of rocks, deeply cultivated and beds installed over the whole area. An alley tree-farming enterprise, buffer catchment dams, permanently vegetated waterways and water run-off monitoring were incorporated into the farms' design. A scientific run-off trial, funded by GRDC, comparing raised beds, flat shallow cultivation, flat deep cultivation and pasture has been carried out on one concept farm for the past five years by Tim Johnston from the Victorian DPI. Dr Renick Peries, SFS Southern Farming Systems soil scientist, was appointed in 1998 to study all aspects of structure on the cropping soils of south-west Victoria. He has shown that there is a significantly improved soil structure under raised beds, even to a depth of 40 centimetres. His latest work is looking at subsoil constraints, and the effect of deep ripping and soil slotting below raised beds. Since 1996 there has also been rapid development of specialised machinery. Many improvements have been made to the original bedding machines and modern deep rippers are now commonly used to loosen soil before bedding. Combines, drills and air seeders are all still used to sow raised beds. They have been found to be excellent if good quality beds exist. However, on difficult soils with undulations and rocks, beds are quite often not made even enough. Many farmers now use press wheel depth control for seeding. Three machinery manufacturers in Geelong have joined forces to manufacture what they believe is the ideal machine for raised beds. Their machine has been designed to install the beds, renovate the beds and sow both raised bed areas as well as flat areas. Lightness and strength has been paramount in their design. GRDC RESEARCH CODE SFS 00007, program 4 For more information: Bruce Wightman, 03 5226 4667, bruce. email@example.com. gov.au, Dr Renick Peries, 03 5226 4827, firstname.lastname@example.org. gov.au, Col Hacking, 03 5229 0566, email@example.com FEATURE 14 AUGUST 2004 RAISED BED SYSTEMS On the move: (from left) Harry Green, Rex Watson and John Knuckey. PADDOCK DESIGN n Raised bed paddocks are, in effect, a network of surface drains. Collector drains at the end of the beds can carry a large volume of water and, unless they are properly designed and sloped, puddles remain after rain. Paddock traffic can easily bog these areas. n Recent developments have seen the inclusion of an underground drainage system placed under these collector drains and backfilled with coarse gravel. So far this seems to work and it keeps dry the headlands used for vehicle turning. Bruce Wightman, an agronomist with the Department of Primary Industries, Victoria, outlines the development of 'bed farming' in high-rainfall cropping zones, and the innovations that are making this one of the grains' sectors fastest-growing new systems. When local business rivals come together to combine their expertise to design and build a superior piece of farm machinery, something clearly is on the move. In the case of farm machinery manufacturers Rex Watson, John Knuckey and Harry Green, who run separate businesses in south-west Victoria, the 'something', is a machine to sow raised beds. The three manufacturers had all been making various components for air-seeders, but became convinced that an assembly of add-ons was unlikely to be as good as if they got together and customised their components for a single machine. Mr Watson, who runs Watsons Farm Machinery in Geelong, was manufacturing frames, Mr Knuckey, from Knuckeys Winchelsea, was making press wheels and sowing tubes, and Mr Green, from P.J. Green Engineering, also in Geelong, was making seed boxes and seed distribution components. The issue confronting growers, and which was passed on to the manufacturers by local agronomist Bruce Wightman, was the need for more accurate sowing depth. The manufacturers all had plenty of ideas, but no common platform, explains Mr Green. The three manufacturers decided the best way to achieve improved accuracy was to incorporate the air seeding and tillage into the design of a Watsons bar. The trio agreed on designing for two-metre beds, and also on hydraulic and straight-backed tynes to reduce soil throw. Mr Watson says the three manufacturers shared the growing enthusiasm for high rainfall cropping and that it was probably the first time local farm machinery rivals had come together to keep machinery design in step with grower experience. Changes observed in GRDC- supported studies of raised- bed soils include: n prevention of waterlogging which appears to have led to an increase in depth of aggregates, thought to be due to better wetting and drying of the root zone; n improved friability creating a better environment for root growth, plus improved seed- soil contact, uniform crop establishment, and improved workability. Research has also shown that tactical grazing can minimise damage to soil structure caused by wet weather. It has been shown that a crop can be sown direct onto beds, following grazed pastures, without the need to reform beds. Victorian Department of Primary Industries research scientist Dr Renick Peries says that after three years of raised bed cropping, both the black cracking clay and grey-yellow duplex soils studied tolerated higher water content before they started losing friability or causing machinery slippage. He says this should give farmers a greater window of opportunity for sowing and other operations compared with flat cropping. Dr Peries says that during the 2002 drought, raised bed farmers reported the lowest yield declines, and many still achieved average to above average yields despite low rainfall -- because of improved soil structure. Growers hop into beds of promise Rivals combine to get the best result Growing trend: wheat in raised beds in southern Victoria.
Ground Cover 052 October-November 2004 - North
Ground Cover 050 June-July 2004 - North