Danish Institute of Agricultural Sciences

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Danish Institute of Agricultural Sciences
Micro spraying weed seedlings
By I Lund H T Søgaard Dept. of Agricultural
Engineering E Graglia Dept. of Crop Protection
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Aim

• To reduce the herbicide consumption
• To reduce the contamination of the environment
• Spray drift
• Soil surface losses

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Why micro spraying?
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100 weed plants per ha.
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Potential for herbicide savings

• Surface coverage at 100 weed plants per ha. is
  less than 10 of the total soil surface

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How to deposit a few µl?

• Plant species
• Wax layer
• Leave angle
• Spray formation
• Droplet size/velocity
• Spray mixture
• Surface tension
• Viscosity

Foto Rhodia http//physicsweb.org
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Hypodermic tubes
Small Parts, inc.
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Droplets on a solid surface
Water
Waterpolyethyleneoxide
Photo http//physicsweb.org
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Deposit on a artificial surface
Water
Water PEO
Water PEO Silwet (surfactant)
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Micro drift at 50 mm distance
Water
Water Surfactant
Water Surfactant PEO
ASAE-Paper Number 031154
Photo Ken Giles,UCDavis
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Single droplets and biological efficacy

• Black Nightshade (Solanum nigrum)
• Glyphosate in range 0.125 1.0 µg

Enrico Graglia
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Applying with pipettes
Photo Enrico Graglia
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Photo Enrico Graglia
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Biological efficacy
Enrico Graglia
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Effects of glyphosate on Black Night Shade

• Doses 0,8 1 µg Glyphosate per plant
• Treatment efficacy 95
• In field situation with 100 plants per m2
  1 g Glyphosate per ha.

Enrico Graglia
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Micro spray system

• Micro-spray system (UC Davis)
• Apply herbicides at individual weed plants
• Computer vision
• Discrimination between crop, weed and background
  (soil)
• Autonomous robot
• Robotic vehicle that navigates autonomously

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The Autonomous Robot
RTK-GPS antenna
Micro-spray boom
Web camera
Photo Henning T Søgaard
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The Micro Spray System and Camera
Web camera
Micro-spray boom
Photo Henning T Søgaard
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Micro Spray Boom
Solenoid valve
Inner diameter of needles 0.51 mm
Henning T Søgaard
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Micro Spray Boom
Henning T Søgaard
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Test Course

0.4 m
0.3 m
6 m
Henning T Søgaard
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Image Processing and Spraying

• Identify circles (by size/shape)
• Determine cells to be sprayed

Henning T Søgaard
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Sprayed circles
Test course traversed 3 times
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Accuracy Measure
Travel Direction
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Results
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Results
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Relative Frequency ()
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0
0
1
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10
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Distance (mm)
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Precision of Micro Spray System

• Sub-centimetre accuracy under indoor conditions
• Higher accuracy achievable by increasing the
  ground resolution

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Spray Map
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New prototype of Micro Sprayer
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Thank you for your attention