Introduction

At the heart of the DBS is the patented precision seeding DBS Three Slot System.  Each slot has its own environmental characteristics, which assists plant development.  The first slot breaks through hardpans to create moisture and air pathways, the second slot sees the seed placed at a precise depth in disturbed but stabilised soil, while the third slot is more commonly described as the water harvesting trench. 

Over the past ten years, DBS owners, who have embraced this pioneering concept in conjunction with a “systems approach” to sustainable farming, have witnessed improved soil structure and fertility through increased organic carbon levels.  The consequences for them have been higher yielding crops and more productive pastures.  In tight finishing years characterised by high screenings, DBS owners have also reported crops ‘hanging on’ better and producing less screenings at harvest with higher hectolitre weights.

The DBS system consists of a high breakout hydraulic tine with deep digging blade attached and a parallelogram precision seeding mechanism comprised of  a press wheel and closing tool, each having a specific function to perform.  The positive seed depth control of each individual DBS unit combined with effective under seed cultivation at depth are two of the key factors that make the DBS system so successful.
 
Horsepower Requirements

Horsepower requirements range from 3.7 kW to 7 kW (5 to 9 hp) per tine at operating depths of 5 to 9 inches.  Thus, a 40 ft machine on 10" spacings (48 tines) requires approximately 284 kW (384 hp) using 7" blades. These ratings obviously depend on soil types, moisture levels and tine spacings.  As a general rule of thumb hovever, a tine will require one horsepower per inch of blade used.  ie, a 5" blade uses 5hp per tine and an 8" blade uses 8hp per tine. 

Customers who are faced with the prospect of upgrading both their bar and tractor in one season can often ’split’ the purchase of bar and tractor by using shorter blades in the first season, and then upgrading the tractor at a later date.  In any case, the parallelogram seeding system ensures regardless of digging depth, seeding depth accuracy is maintained. 
 
Recoil Oil Circuit System

A large 20-litre nitrogen gas accumulator (pre-charged) is used to provide high force at the digging point and is also used as a gas cushion. When a tine encounters an obstruction below the soil surface, oil is discharged from the jump cylinder, which acts against the accumulator’s gas cushion, allowing the tine to jump freely.  Restricted return flow valves are fitted to the jump cylinders, eliminating the possibility of oil bypassing the accumulator and flowing quickly to a returning jump cylinder when many jump cylinders operate simultaneously. This ensures a soft, positive return to digging position for each individual tine assembly.

Though it is usually not necessary, it is possible to alter the digging pressure by varying the oil circuit pressure, or in specific situations the accumulator gas pressure can be adjusted by Ausplow service personnel.   Those machines that have more than 40 tines and are operating in extremely rocky conditions can be fitted with a second accumulator to avoid higher internal hydraulic pressures when the majority of tines on a machine ‘trip’ at the same time.

Tine Mechanism

Tines are manufactured from forged, heat treated 90mm x 20mm spring steel.  Mounting is edge-on for maximum digging strength while providing ample side flexing. All holes and mountings are drilled using CNC machining for accuracy and interchangeability.  All pivot pins are hardened steel and greasable with replacement bushes.
 
Machines are factory set to provide a digging force of 340kg (750lbs) at the blade point, with lower or higher settings also possible.  The 63.5 mm (2 1/2”) diameter hydraulic jump cylinder has the unique feature of an internal seal-wiping system with no working surfaces subjected to damage or corrosion. 
 
DBA Digging Blades

Genuine Ausplow blades are forged from spring steel for strength and durability and heat treated for hardness and wear resistance. They are available in five standard lengths to suit varying soil conditions and operating depths.  A digging tungsten tile is fused to the bottom of the blade and protective tiles are fused above this digging zone to protect the blade face up to 130mm to maintain proper digging action. The top protective tile has a rounded face to decrease pressure at the soil surface, therefore reducing the amount of soil throw.
 
An important feature of Ausplow blades is the rounded smooth head shape and rear angled attachment. This shape allows root material and surface trash to freely move away from the blade-shank zone reducing furrowing and allowing the slot system to function correctly.  Another important feature of the rounded blade shape is it’s ability to throw a small quantity of soil onto the inter-row which covers and retains residual herbicides used for low cost effective weed control.
  
Parallelogram

The parallelogram linkages are produced from rolled spring steel which is heat treated for strength.  The thin section reduces weight and adds flexibility while turning. The in-line design has no side forces and is not damaged when jumping or returning to the digging position by soil obstructions and frame interference.  Fixing the press wheel in line also prevents the press wheel ‘jumping’ out of the seed trench, eliminating associated depth control issues.

The parallelogram has a vertical travel of 250mm (10”).  Bearings are hardened, pre-lubricated and sealed.  An adjustable tension spring provides downwards pressure on the closing tool and press wheel, and this tension effect maintains a live ground following action. This is important for precision seed placement. Double pressure springs can also be fitted when operating in heavy clay conditions.

Fertiliser Pipe

The shaped and powdercoated steel pipe is attached to the rear of the tine and has a 33mm inside diameter, allowing it to accept a 32mm diameter polythene hose directly from the airseeder. Optimum fertiliser placement can be adjusted for either banding or profiling by fitting or removing optional fertiliser boots.  

Seed Tube

The seed tube comprises of a steel pipe for conveying seed and / or seed and fertiliser onto the seedbed. A rib assembly is welded to this pipe for strength and contains rear linkage bearings, press wheel, adjustable seed bed forming tool and wheel scraper.  The seed tube also accepts 32 mm outside diameter poly hose from the airseeder.  A rubber seed boot is attached to the bottom of the seed tube to further control seed placement and reduce dry soil flow onto seed bed.
 
Closing Tool

This tool is specifically shaped to close the digging blade slot, providing a wiping action which produces a firm, even seed bed.  The curved bottom stops the surface of the seed bed tearing and the rear edge of this tool is faced with a tungsten tile, giving long life and ensuring an even closing action throughout it’s operating life in both sand and clay soils.  Raising or lowering the closing tool alters seed depth. Closing tool positions are in 8mm (1/4") increments.

Press Wheel

The press wheel has three unique functions.  It acts as a gauge wheel, covers the seed with soil and presses the soil in a firming action to obtain optimum soil - seed contact.  A flexible, self-cleaning 50, 70 or 90mm wide flat faced rubber tyre is used to create a wave action causing the soil to flow inwards and cover seed. The wheel sides have a curved shape which increases sidewall pressure, maintaining trench shape until seeds germinate.  All tyres are self cleaning and have wire moulded into the beads which eliminates tyre roll off.
 
For heavy clay soils, the narrower 50mm tyre is the optimum choice. It has a smaller footprint giving it a higher surface packing pressure.  It also allows greater clearance on side arms during wet conditions to shed mud build-up.  The 70mm press wheel is the most common press wheel used, suitable for heavy loams through to sandy soils.  Finally, Ausplow offers a 90mm press wheel for deep sandy conditions where the side walls of the seed trench may be prone to collapsing.  

Auseeder Frame

The DBS Auseeder frame is constructed from 100mm x 100mm x 9mm  heavy duty steel wall section.  To add additional strength, the frame is fully trussed to eliminate any frame twisting when working in difficult conditions.  A fully trussed 200mm x 100mm fixed drawbar is also used which offers exceptional strength and frame stability too.

Why we don’t have a floating drawbar?  Firstly, a floating drawbar requires castor wheels to be fitted in front of the bar.  This removes the bar’s lateral stability and causes the frame to work in a similar manner to a shopping trolley.  With the current demands of controlled traffic and tram line farming,  optimum lateral frame stability, a well recognised attribute of Auseeder frames, is essential.

Secondly, our competitors rely on the frame being positioned at a set distance above the ground to achieve depth control.  The DBS parallelogram on the other hand gives the industries best seeding depth control due to  the combined action of the closing tool and press wheel.  As long as the digging depth is greater than the seeding depth, the DBS will always seed at the set depth required.  The Auseeder frame is fitted with large diameter tractor lug type tyres including dual centre frame wheels which provide excellent floatation in the wettest seeding conditions. 

All models can also be fitted with optional 18" coulters if required.  Two types of coulters are available.  Single coulters offer higher cutting pressures whereas double coulters are more desirable in wet, clay conditions. 

DBS Auseeder Shines in Wet Year

The 2005 seeding’s wet weather was an excellent learning experience for Ausplow because it showed the benefits of the DBS Auseeder in sowing in either wet or dry conditions.  DBS-tilled paddocks created better drainage and because of the nil inter-row disturbance, it was easier to get spraying rigs onto paddocks which with conventional cultivation would have developed boggy patches and ponding.