AGR 3102 (1) Principles of Weed Science Herbicide

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AGR 3102 (1)Principles of Weed
ScienceHerbicide

• Muhammad Saiful Ahmad Hamdani

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Week 12 Topics Covered

• Critical Factors Influenced Spraying
• Herbicide Calculations

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• Critical Factors Influenced Spraying Process
• Product label spray condition recommendation
  (MANDATORY)
• Wind speed and wind direction
• Temperature relative humidity (both soil and
  air)
• Sprayer height speed (depending on spray
  quality)
• Local weather condition

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• If you cant measure the conditions at the site
  of application, you cant make an informed
  decision about when to change setup or when to
  stop
• Monitor and record conditions at least every
  load.
• More often at night ...if the wind stops, STOP
  spraying

Photograph by Graham Betts
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What are suitable wind speeds?

• The maximum wind speed should not be above 20
  km/h and preferably around 15 km/h.
• Higher wind speed can be managed when we have a
  canopy to catch the droplets.

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Herbicide Calculations
Products/formulations active ingredient (a.i.)
a series of inert ingredients. Spray
recommendations come as either product/area or as
a.i. per area.
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Pure form
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Herbicide Calculations cont

• Some herbicides, trade name is followed by a
  number and letter designation.
• The number indicates how many g of a.i. are in a
  L (for liquid formulations) or g (for dry
  formulations) of the formulated product.
• Examples

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First Thing To Do Before Calculating Herbicide
Amount Required For An Area
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Herbicide Calculations cont

• a.i. Calculation
• - a.i. is always identified on the herbicide
  label.
• - often expressed as either a or in g/L.
• - calculations based on dry or liquid
  formulation.

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• Several calculations to determine the amount of
  a.i. applied. One of the easiest calculations
• g a.i. applied per ha
• kg or L of product applied per ha X g active
  ingredient per L or kg of product
• Product/tank (L or kg) product recommended
  rate/ha X tank size (L)
• application rate (L/ha)
• Example calculation of dry formulation
• - Herbicide Plantgard with 30 2,4-D (note 30
  w/w in trade
• formulation 30g a.i. in 100g product or 300g
  a.i. in 1kg product)
• - Spray recommendation 2.5kg product / ha
• - How much is the 2,4-D in the product when we
  apply
• 2.5kg of Plantgard per ha???

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• g a.i. applied per ha
• kg or L of product applied per ha X g active
  ingredient per L or kg of product
• g a.i. applied per ha
• 2.5kg Plantgard/ha X 300g a.i. 2,4-D/kg
• Answer 750g a.i. 2,4-D per ha applied when
  spray at recommended rate of 2.5kg
  Plantgard per ha

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• Example calculation of liquid formulation
• - Herbicide Gramoxone with 35 paraquat (note
  35 w/v in
• trade formulation 35g a.i. in 100mL product or
  350g a.i. in 1L product)
• - Spray recommendation 3kg a.i. paraquat / ha
• - How much is the Gramoxone required when we
  apply
• 3kg a.i. paraquat per ha???
• g a.i. applied per ha
• kg or L of product applied per ha X g active
  ingredient per L or kg of product
• 3000g paraquat per ha ?L Gramoxone/ha X
  350g a.i. paraquat/L
• Answer 8.57L Gramoxone is required for 1ha when
  spray
• with 3kg a.i. paraquat per ha

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Exercise 1 Refer to your herbicide label

• Calculate how much is the a.i. actually applied
  per ha when the product is sprayed at the rate as
  recommended?
• How much is the product required for a knapsack
  sprayer with spray capacity of 20 L
• The number of spray needed to spray 1 ha area
  when use a 20 L knapsack sprayer

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• Exercise 2
• Lasso 500EC (a.i. alachlor) recommends to spray
  30mL Lasso for every 5L water.
• 1ha area required 450L water.
• Calculate
• a. How much Lasso is required per ha?
• b. How much g a.i. alachlor is applied when
  spray at recommended rate per ha?

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• a. Lasso required per ha
• Recommended rate 30mL Lasso 5L water (1 ha
  required 450L water)
• ?mL Lasso 450L water (1ha)
• 30mL Lasso X 450L water
• 5L water
• Answer 2700mL (2.7L) Lasso is required per ha
  for a recommended rate
• b. g a.i. alachlor applied per ha when spray at
  recommended rate
• kg or L of product applied per ha X g active
  ingredient per kg or L product
• 2.7L Lasso/ha X 500g a.i. alachlor/L
• Answer 1350g a.i. alachlor per ha applied when
  spray at recommended
• rate of 2.7L Lasso per ha

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Exercise 3

• Herbicide KillDaWeed contains butachlor granules
  (15 a.i.) with the application rate of 2 kg
  a.i./ha. How much (kg) is the KillDaWeed required
  to treat a 50m2 with rate as recommended by the
  label?
• Herbicide Cleansweep contains glyphosate (36
  a.i.). How much glyphosate is required to treat a
  2000m2 plot at the rate of 3.0 L Cleansweep/ha?

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THANK YOU!!!!!