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action and to obtain more knowledge about weeds as not all the her-
bicides within a particular chemical group or mode of action controls
the same spectrum of weeds.
There are also major differences in weed types found in different
climate zones, districts and even between fields on the same farm.
The importance of water quality for better
weed control
Dr Brian de Villiers (product manager: Villa Crop Protection) has over
many years conducted ground-breaking research on water quality
and its influence on the efficiency of herbicides and has also become
a specialist on the efficiency of additives. He discussed the basic
aspects of effective weed control, such as nozzles, spray speed and
the role of wind as well as water volume which also plays a large role
in the effective application of herbicides.
Dr De Villiers underlined the importance of water quality and
water pH when using herbicides. Water containing high dissolved
salts (brackish water) will cause poor herbicide efficacy especially
in glyphosate use. Water with low dissolved salts or “soft water”
causes high foaming of chemicals and incompatible spray mixtures
as it cannot maintain the pH at a specific point. In high pH water
pesticides are degraded and less effective. He encouraged pro-
ducers to have a water analysis done and to use the correct adjuvant
to solve the specific problem on their farm.
A soybean producer’s viewpoint
Weed control affects all soybean producers. Mr Cobus van Coller
(Grain SA member of the Executive) has had to overcome many
challenges in effective weed control, with soybeans being a
relatively new crop on the sandy soils of the Viljoenskroon district
where he farms.
Van Coller started planting soya on a larger scale in 2010 and shared
his perspective on how a producer can deal with weed control in
practice. He mentioned that where net profit per hectare is con-
cerned, soya comes out on top as far as financial advantages are
concerned.
He shared a few essentials with other producers:
Crop rotation gives you an excellent opportunity to use a variety
of chemicals.
September 2015
82
FOCUS
Integrated pest control
Special
Effective weed control beneϐits
soybean plantations
4: Stefan Maree (producer from Odendaalsrus), Fires van Vuuren
(agent: Laeveld Agrochem, Kroonstad) and Whitey van Pletzen
(production manager: Agricol, Potchefstroom).
5: Discussing the information shared during the first two sessions of
the symposium, are Mpuana Ralesekele (producer from Japie Farm,
Ventersburg area), Patrick Mokoena (technician: ARC-GCI) and Edson
Ncube (pathologist: ARC-GCI).
3: Gawie de Beer (contractor: PRF), Johan Bothma (business develop-
ment manager: Dow AgroSciences), Dr Jan Dreyer (previously from the
ARC-Grain Crops Institute) and Lood Büchner (South African agri grain
manager: Free State Maize) enjoying the winter sunshine on a cold day.
4
The most important key in soya cultivation is inoculation.
Have water quality tested regularly for pH and salts to ensure
that the correct adjuvants are added.
Test nozzles and sprayers on a weekly basis to ensure even
spraying.
Poor proper planning leads to pathetic poor performance.
5
3
“
The projection of reaching
the 2 million ton mark by
2020 is well in reach of South
African producers...
“