1. Zero tillage: Weed management in lentil
Fact Sheet -Weed Control
Zero-till (ZT) planting can reduce production cost and increase yields – provided weeds are controlled. This fact sheet describes weed management for ZT lentil (masoor).
Lentil is infested by many weed species; especially broadleaf weeds like Chenopodium album (bathuwa), Vicia sativa (akta), and Lathyrus (ban matri). These weeds produce large quantities of seeds – for which they ‘steal’ large quantities of nutrients and water from lentil. Volunteer lentil plants are also a problem in some fields. They compete with crop plants during critical periods (e.g. flowering) but do not provide yield, because they shed seeds before the regular crop matures.
Tips for weed management
Plant in a clean field: knock down germinating or established weeds and volunteer lentils with total killer e.g. glyphosate.
Use a vigorous variety that can compete with weeds. A healthy crop has fewer weeds than a weak crop.
Timely planting, so that crop plants are well established when weeds are still small. This reduces competition.
Retain crop residue: presence of residues reduces sunlight to germinating weeds, and also improves crop growth through better moisture retention. This reduces weed density and weed competition.
Use correct dose of herbicide: over-dosing means extra cost with
no extra benefit. Under-dosing results in weed resistance to herbicides.
Use herbicide with full package: use recommended herbicide in the recommended way, along with good crop management.
Crop rotation, herbicide rotation. Crop rotation prevents build-up of weeds, pests and diseases. Herbicide rotation (whenever possible) prevents herbicide resistance and improves weed control efficiency.
3 -nozzle boom for herbicide application
Spray techniques
Use pressure regulators and flat fan nozzles fitted in spray booms.
First dilute required herbicide in a little water. Then add more water to make final spray solution.
Multiple nozzle boom gives more uniform coverage than single nozzle.
Always give 30% overlap, to ensure that no areas are missed.
Use clean water for spray solution.
Always wear protective clothing while spraying.
Calibration of sprayer
Calibration will ensure that herbicide is properly applied, with correct dosage.
To calibrate the sprayer:, mark distance of 25 meters. Spray the whole distance with “swathe” of 1.5 m with a nozzle boom. Measure how much spray volume has been used. Calculate spray volume needed for field, adjust sprayer settings accordingly,
  Walking speed: if nozzle capacity is high, walk faster to maintain correct dose per square meter.
Spray pressure: increasing pressure by 4 times will increase output by 2 times.
Low volume sprayer leads to drift and poor coverage. Use high volume sprayer with l/ha.
Which herbicide to use?
Only a few herbicides are available for legumes.
Pendimethalin and alachlore: pre-emergence herbicides
Quizalafop: post-emergence herbicide
Glyphosate: pre-planting herbicide, recommended if field is infested with germinating or established weeds at planting time e.g. Cynodon dactylon (doob) or Cyperus rotundus (motha). Add ammonium sulphate 2% to improve efficiency.
Herbicide
Dose (g.ai/ha)
Dose (l/ha)
Stage
Target weeds
Glyphosate
1000
2.5
Pre plant
Perennial weeds
Pendimethalin
3.3
2-3 DAS
Gr, some BL
Pendimethalin CS
750
2.2
Alachlore
1250
Quizalfop/ 60
1.2
4-5 leaf Gr
DAS: days after sowing, CS: capsulated suspension, Gr: Grasses, BL: broadleaf weeds
4 m wide 8 nozzle boom for better coverage and weed control efficiency