compete with soybean for light, space, water and nutrients. Soybean plants
are quickly overgrown. If weeds are not controlled on time, soybean yield
will be very low.
can be controlled mechanically by pulling out, harrowing, or tillage. Some
serious weeds can be chemically controlled. Be careful, some chemicals can only
be sprayed before soybean germinates.
kills any plant, also soybean. Thus, spray before sowing, or after sowing but before
soybean germination. Trade names: Cycat,
Round up, Muscle up, Springbok, Scat,
Erase, and others. It is of WHO toxicity class III, thus slightly toxic to
kills broad leaf weeds. Apply according to the label for not killing the beans.
Spry when soybean and weeds have
emerged, but before weeds exceed 5 cm. Trade names: Classic or Bean weed killer. It is of WHO class III, thus slightly toxic to
you. Pre-harvest interval 45 days.
only kills grassy weeds including kapinga. Trade names Pantera or Quizate. It is
of WHO class II thus moderately toxic. If a field has grassy and broad
leaf weeds, you can mix chlorimuron and quizalofop in one sprayer or drum.
For spraying glyphosate
a small hole fan-jet nozzle (orange), that makes a fine spray.
700 ml or 500gm in a 16-litre sprayer. The usual rate is 4 litres product /
hectare. But double-check label as the products differ.
spraying, the soil may be dry or moist; weed leaves should be young and fresh
but not wet. Spray at dry weather or at
least 4 hours before rains. Do not enter the field for ½ a day at least.
spray when soybean has emerged, because it kills beans.
For spraying chlorimuron or quizalofop
a blue fan-jet nozzle which has a bigger hole.
3.5gm chlorimuron sachet in a 16-litre sprayer; or 300gm sachet in a 200-litre drum of water
mix 130ml quizalofop in a 16-litre backpack sprayer; or 1.5 litres in 200 litre drum of water per
ha. But double-check label.
When spraying, weeds should be fresh but not
wet, soil can be dry or wet.
spraying hold the nozzle 1/2m high from the ground along planting lines walking
50 meters in 45 seconds. Do not enter the field after spray for ½ a day at
When using a pesticide, always wear protective clothing and follow the instructions on the product label, such as dosage, timing of application, and pre-harvest interval.