Farmers Review Africa Nov-Dec 2018 Farmers Review November-December 2018-6 | Page 20

FEATURE
Sorting above the standard:
when optical sorting is the last resort
T
he future of seed and grain
sorting is a bright light. Is it?
Indeed, advanced optical sorting
systems with divergent optics and
illumination techniques are a booming
trend. The range of optical sorting
systems is increasing and more and
more vendors are on the market.
Sometimes, general promises such as
steady sorting accuracy levels of > 99%
are proclaimed. Theoretically it is possible.
Often it is also practically possible.
But as nature is highly variable and
never constant, accuracy levels for all
lots or sorting tasks of 99% are not
realistic. But fact is, that optical sorting
can rescue production and prevent
tremendous revenue loss.
In certified oat seed production in
Europe, there is a zero tolerance for
wild oat. A Spanish oat seed producer
faced the issue of having 5714 kernels
of wild oat in 1 t of mechanically
cleaned oat seed (0.02%). The official
certificate would have been labelled
with “not certified”, as his own 5.5
kg sample analysis with 31 wild oat
kernels indicated. Ten hectares of seed
production most probably lost and to
be sold as commodity.
With an average oat yield of 2 t/ha and
a commodity price on the CBoT stock
exchange with € 250 /t, the difference
in revenue between commodity oat and
seed oat would have been € 5,600;
excluding the higher price of the field
production. With a yield of 5 t/ha, the
difference would be € 14,000.
The sample was sent to the ROEBER
Institut GmbH, a member of the
PETKUS Group, in Wutha-Farnroda
(Thuringia/Germany) where it was
analysed before and after optical
sorting with the OS 901 with one re-
sort cycle. Wild oat could be completely
separated by the OS 901. The “accept”
fraction showed a purity level of > 99%.
There were no kernels of wild oat left in
the sample after sorting.
©PETKUS GROUP
The brand-new PETKUS/ROEBER OS f-class was presented at the “Seed meets Technology” fair in Zwaagdijk/Netherlands in 2018 (source: PETKUS Group).
18 |November - December 2018