HOW TO USE THE RBM SYSTEM FOR FARMING
DAVID McGrath does not have a farming background but he has certainly made the agricultural world sit up and take notice of his leading-edge cultivation technology.
Mr. McGrath is the principal of Sustainable Agricultural Machinery (SAM) in Wodonga and first rose to prominence in the farming world when he took out The Land newspaper Inventor of the Year Award in 1990 with his Raised Bed Management System.
He is vitally interested in farms becoming sustainable and has been a proponent of the raised bed management system for a number of years.
He is frustrated at the slow uptake of this system among conventional broadacre farmers, who could overcome waterlogging problems and improve crop yields and soil structure.
But the reaction among horticultural farmers has been positive with many recognizing the benefits almost immediately.
SAM has sold to carrot producers in New Zealand, ti-tree growers at Lismore, potato and onion growers in South Australia, lettuce, broccoli and carrot growers at Bairnsdale.
In seven years of business in Wodonga, David now has 47 designs all based around sustainability and the conversion of old equipment to new.
One of his designs, the RBM concept, is the only one of its type in the world and forms raised beds in one pass.
Deep rippers can be added to the bedformer or fertilizer bins added for urea placement.
Originally, a friend involved with organic farming got McGrath thinking about the concept as equipment of this type was unavailable on the Australian market.
Mr. McGrath said the bedformer was designed not to be a soil destroyer and could work at 2-3 acres/hour with deep rippers attached.
Under broadacre applications, the triple bed former can work at 11.9 acres/hour including deep ripping the bed surface and compacting the beds.
The compaction rates are designed to suit the individual soil type.
“Rotary harrows and power harrows really chop up the soil and that is not what we are trying to achieve,” Mr. McGrath said.
“It is designed with no moving parts and can be adapted for horticulture right through to broadacre applications. Once the bed is formed in the paddock, you then require guidance to sow the seed or transplant the speedlings.”
A second machine, a Bedlocker, is the guidance system for all subsequent operations on these beds.
It places the seed in relation to the bed side.
It also sets the scene for the Power Weeder, which is the heart of the raised bed management system.
“The concept of raised bed management is just starting to catch on now, especially in the horticultural industry where farmers are diversifying into Asian vegetables and other alternative crops like mint, flowers and pharmaceutical herbs,” Mr. McGrath said.
All of the SAM equipment has been designed and manufactured locally.
Bedlocking is the second phase of raised bed management concept, giving guidance from the compacted beds which act like rails or tram lines for accurate sowing-planting.
The Bedlocker is a universal tool bar that fits between the tractor and implement.
The front of the tool bar locks on to the bed and through universal three point linkage mounting can accommodate any width or widget, and fit any three point linkage configured unit.
“Once you have locked the implement on, a set of skis at the rear will guide it off the bed with an accuracy of plus or minus 5mm,” Mr. McGrath said.
“Farmers can go into the paddock with a tolerance of plus or minus 5mm and know the plant will be there from one end to the other.”
The heart of the RBM system is the Power Weeder, which has been designed to eliminate most of the labor associated with weed control and the use of expensive chemicals.
Mr. McGrath said the Power Weeder was designed to work in all soil conditions, from sand to heavy clay, and is width and height adjustable.
“The front has two Teflon-coated skis that lock on to the bed shape. On the rear of the outer frame are two rebuilders which lift the soil out of the base of the furrow and reform the size of the bed to its original shape.
“The inner deck of the Power Weeder has constant depth control via two skis which follow the contour of the bed top, also setting the scene for the depth of the knives.
“The PTO-driven weeder has two oscillating tool bars which knife blades are clamped to. This oscillating movement allows the knives to be self-cleaning, self-sharpening and as the weeder passes, the farmer is left with uncultivated strips on the bed surface.”
The machine fits to the rear of the tractor with the sway chains loose, hence the weeder is guided by itself and not by the tractor operator.
It comes standard for three rows of crop on its bed surface but any number of rows of crop can be accommodated.
There are many optional components that have been designed for the system, including inter plough frame, a bed renovator toolbar, deep rippers and adjustable clamps through to two variations of foliage guards.
Mr. McGrath has worked with Maffra vegetable grower Bill Taylor to trial the machines on lettuce, broccoli and carrot.
The SAM bedformer is also being used in Agriculture Victoria trials on nine sites under a project called Southern Farming Systems.
The former is being compared with a rotary hoe, power harrows with bed shapers.
The bed shaper is also being compared with conventional flat country growing.
Mr. McGrath said raised beds proved their worth last year at Thoona, where a large swampy paddock produced a high yielding canola crop under the RBM system.
He said the system offered the farmer an opportunity to grow crops which would otherwise die of wet feet.