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The science of seed treatment

on soya beans

By Jaco van Zyl, Bayer Crop Science

eed treatment has been professional attention in terms of Soya bean seeds are vulnerable to
around for many decades and successful planning and implementation. splitting during handling and require
is becoming an important equipment designed to limit splitting.
part of integrated pest Efficacy of seed treatments
S management. The main Soya bean is a growing crop in South Application of biologicals
objective of seed treatment is to increase Africa, and it is therefore important to Applying biological- and chemical-based
the yield potential of a carefully chosen understand and learn about the value products together can be challenging, as
seed (adapted to specific growing areas) of seed treatment as a key component their physical characteristics vary quite
and to protect it against certain seed- in the production process. Soya bean significantly. This compatibility challenge
and soil-borne insects and diseases. seed can be particularly tricky to treat, therefore requires separate applications
Seed treatment is not only essential firstly due to the physical characteristics in the same treatment process and can
for successful crop establishment, but of the seed surface, and secondly due be achieved when mixing these products
also acts as a ‘vehicle’ to apply other to the integrity of the seed structure. together, if the mixture can be kept in
key components such as Rhizobium Soya bean seed can be damaged suspension by means of agitation.
(inoculants) for nitrogen fixation in quite easily, especially when incorrect Applying biologicals such as Rhizobium
the case of soya beans. It is therefore seed treatment processes are followed are particularly challenging, as the
a convenient application method, as or when using seed treatment organism does not survive on the seed for
you can load the required products equipment not suited to the task. very long (normally limited to 30 days).
on the seed to be available from the Pre-season treatment is therefore limited,
start of the plant’s life; it is thus target Physical characteristics in many cases forcing the industry to treat
specific in terms of area of application Soya bean seeds have a smooth surface that seed non-professionally, literally just before
where protection is required. complicates the drying process as well as planting. Soya bean seed is therefore
However, seed treatment is in many adhesion of the seed treatment. In order to typically sold without an inoculation
respects a much wider field than simply ensure maximum efficacy of the products and only treated with a fungicide.
putting product on the seed. A holistic being used, the correct equipment, Stewardship risks emerge when
approach is taken when treating seed calibration and recipe of products added re-treating seed, which can cause a loss
and it normally comprises products, together is key. The seed treatment mixture of the initial treatment. In such a case
equipment, stewardship and the should first be registered and tested ‘in-furrow’ application of the Rhizobium
individuals who treat the seed. The before use, to ensure a favourable return should rather be considered to avoid losses
treatment process therefore requires on investment and limited relevant risks and be considerate of the environment,
(including compatibility). the safety of the operators and the
Without accurate loading sustainability of the molecules available.
of the products on the
seed, poor efficacy can be The role of people
expected, leaving the seed People play an integral role in successful
less protected and open to seed treatment as precise skills and
resistance risks against the methods are required. In a professional
products applied. Products seed treatment environment, operators
such as fungicides (assuming undergo regular training on general
the correct loading is fully personal safety, safe use of the
available) can significantly products, as well as how to master the
improve the plant population equipment that is used to ensure a
and stimulate vigour due properly cleaned and treated seed.
As soya bean seeds are vulnerable to splitting during handling,
equipment specifically designed to limit the splitting of the seed to the overall healthier It is important to have seed
must be used. seedling at germination. professionally treated where

16 June 2020