Fact Sheet 13
July 2004
Farmtalk is a product of the Mallee
Sustainable Farming Inc. Tri-State
Research and Extension team
Seeding System Considerations
for Stony Soils
Dr. Jack Desbiolles
Agricultural Machinery Research & Design Centre – University of South Australia
The issue
Stony soil conditions represent a significant
farming area in the Mallee. The success
of seeding in stony soils depends on the
ability of the seeding system to maintain
sowing depth uniformity under high tripping
frequency and intensity.
Therefore, using the right seeding system for
prevailing soil conditions can optimise crop
establishment and lead to increased yield
response in these traditionally lower yielding
areas (Figure 1).
amount of tillage below the seed zone, due
to dry topsoil conditions at sowing. Deep
tillage benefits are unlikely to occur under
favourable soil moisture conditions.
• Overall, higher tripping intensity, obtained
through deeper tillage depth or lower
break-out rating, worsened seeding depth
uniformity and reduced crop establishment.
The key to maintaining seed placement
uniformity in stony soils is to ensure the
working position of the seed boot is
maintained at all times within the furrow; for
instance, by matching adequate break-out
rating to tillage depth requirements.
• Following a decile 7 growing season,
10-30% yield responses (0.23-0.69t/ha) to deep
tillage (90mm) were measured. Independently
mounted seed boots yielded 10-11% (0.25t/
ha) better than rigid seed boot systems.
The treatments, which established poorest,
also achieved the lowest yields.
Figure 1. Up to 30% (0.69t/ha) grain yield response to seeding
technology was measured in Mallee trials
The key points to consider are:
• Optimising seeding depth;
• Minimising paddock roughness;
• Point wear and durability issues; and
• Flexibility with contour following seed boots.
What we know
Stony trial results in the Mallee
Trials conducted in the Victorian Mallee
showed that the technology of seeding
systems can significantly affect the uniformity
of seeding depth obtained under intense
tripping activity, as well as the resulting crop
establishment and yield performance.
• Frame wheat established significantly
better with seeding systems involving some
Optimising seeding depth
The following guidelines can improve seeding
depth uniformity in stony soils:
• If moisture conditions allow, match a
shallower tillage depth with enough tine
break-out rating.
• Sow at tillage depth (i.e. cancelling
requirements for furrow backfilling).
•With deep tillage, prefer seeding on a ledge
as in side banding or paired row sowing.
• With deep tillage plus centre row sowing,
furrow backfilling at depth in stony soils is
variable. To improve performance, seed boot
outlets should face rearward, away from the
vertical direction.
• Use high rake angle – narrow point openers
to minimise interactions with, and lifting
of stones.
• Adjust individual seed boots to compensate
for ridging effects on relevant rows.
visit our website www.msfp.org.au
Minimising paddock roughness
Strategies for minimising stone lifting and exposure
to the soil surface (not always consistent with those
for seed placement uniformity) include:
• using disc openers rather than points;
• targeting shallower tillage depths;
• using lower break-out rating trip systems; and
• selecting narrower width and higher rake angle points.
Point wear and durability issues
A practical approach to managing the life span of
ground openers should integrate the following practices.
• Optimise the balance in impact resistance (toughness)
and hard wearing (hardness) properties of point
material and protection.
• Minimise stresses and impact loadings, by adopting
lower travelling speeds, shallower operating depths and
slow recoil hydraulic trip systems. (NB: high capacity
hydraulic accumulators and hose line designs are also
required to minimise dynamic pressure peaks).
• Wear-in new tungsten carbide protected points in easy
soil conditions long enough to at least round off their
sharp edges. This increases their life span in tougher
soil conditions.
Flexibility with contour-following
seed boots
When stump-jumping occurs, a seed delivery system
solidly fitted to the tillage unit partially loses its
performance, especially with ‘double shoot’ systems.
The contour following ability of some seed boot designs
can be used to vary the depth of tillage in adverse
(stony) soil conditions to manage stump-jumping
intensity, while mostly retaining seed placement
accuracy (e.g. Figure 2).
Particular contour following designs, listed below,
are also able to minimise or even cancel the penalising
effects of stump jumping on seeding depth.
• Flexible seed boots (e.g. Agmor UV Boot™)
Self-tracking within the furrow, their length and spring
characteristics allow limited contour-following ability
and may compensate for minor tripping actions.
• Seed boots mounted on a pivoting arm
(e.g. Conserva-Pak™)
Adequate contour followers, these systems become
unaffected by tripping actions from the tillage unit
when attached independently onto a tool bar.
(e.g. Knuckeys™ Sow and Press assembly)
• Parallel displacement seed boots (e.g. Ausplow DBS™)
Good contour followers, they however remain sensitive
to tripping actions from the tillage unit, as all current
commercial designs are attached to tine shanks.
Additional systems combine both the tillage unit plus
seed boot on a contour following device, (e.g. Janke™
parallelogramme planter). Seed boots fitted on such
units remain sensitive to tripping actions, with few
designs able to minimise adverse effects on
seed placement.
Where to from here?
The recommended approach for optimising crop
establishment in stony soils integrates issues of:
• opener selection;
• seed boot configuration and contour following ability;
• break-away system characteristics; and
• operational settings (depth, speed).
Further information is available at:
www.msfp.org.au
(under seeding systems research).
Technical contact
Dr. Jack Desbiolles - AMRDC at UniSA
Telephone (08) 8302 3946
Email [email protected]
Figure 2. Contour following seed boots allow the tillage depth to vary without
affecting seed placement.
Hydraulic break-out designs best reduce impact loads on the implement
when hydraulic pressure peaks in the circuit are also minimised.