Labor-saving Weed Management Tools for Lowland Rice:
Comparing the Use of a Pre-emergence
Herbicide, Rotary Weeders and Ha...
Introduction
• Weeds: important yield reducing factor in
rice in sub-Saharan Africa (SSA)
• Total annual production losses...
Materials & Methods
•
•
•
•

Bagamoyo, Tanzania
RCBD, 4 replicates, 2 seasons
Plot size: 6
8 m
Treatments:
1. Hand weeding...
Results
Twisted-spike weeder

2012

Straight-spike weeder

2013

PE herbicide
Hand weeding
0

100

200

Time (seconds m-2 ...
Results
2012, 21 DAT

Twisted-spike weeder

2012, 42 DAT

Straight-spike weeder

2013, 21 DAT

PE herbicide

2013, 42 DAT
...
Discussion
• Significant time savings with PE herbicide
and rotary weeders on 48 m2 plots
o implications for larger areas ...
Conclusions
• Correct use of herbicides can reduce
farmers’ time for weed management
• Rotary weeders: more time- and manp...
Way forward
• Agronomy
o studying yield advantages, long-term effects
o participatory on-farm rotary weeder tests in
11 co...
DVD
Farmer-to-Farmer Instruction Videos
on Effective and Labor-Saving Weed
Management in Lowland Rice
• 4 multi-language v...
Thank you - Merci - Na som djita
Hartelijk dank
-ご静聴ありがとうございました
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Th2_Labor-saving Weed Management Tools for Lowland Rice: Comparing the Use of a Pre-emergence Herbicide, Rotary Weeders and Hand Weeding

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3rd Africa Rice Congress
Theme 2: Intensification and diversification
Mini symposium: Enhancing productivity through improved water and weed management
Author: Rodenburg

Published in: Technology, Education
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Th2_Labor-saving Weed Management Tools for Lowland Rice: Comparing the Use of a Pre-emergence Herbicide, Rotary Weeders and Hand Weeding

  1. 1. Labor-saving Weed Management Tools for Lowland Rice: Comparing the Use of a Pre-emergence Herbicide, Rotary Weeders and Hand Weeding Jonne Rodenburg Kazuki Saito Runyambo Irakiza Derek W. Makokha Kalimuthu Senthilkumar Africa Rice Center
  2. 2. Introduction • Weeds: important yield reducing factor in rice in sub-Saharan Africa (SSA) • Total annual production losses: 2.2 Mt • Annual economic impact: 1.5 billion USD • Hand weeding: 30-70% (250–780 man hour ha-1) of total labor demand • Weeding 1 ha: walking 10 km head down • Labor-saving weed management technologies are a necessity • Rotary weeders and herbicides • Time gains never comparatively quantified
  3. 3. Materials & Methods • • • • Bagamoyo, Tanzania RCBD, 4 replicates, 2 seasons Plot size: 6 8 m Treatments: 1. Hand weeding at 21, 42 DAT 2. Straight spike floating weeder (A) at 21, 42 DAT A 3. Twisted spike floating weeder (B) at 21, 42 DAT 4. Pre-emergence herbicide (Oxadiazon: Ronstar) at 4 DAT, hand weeding at 42 DAT • Rotary weeding between rows followed by hand weeding in rows • Data: Weed management time, weed biomass and rice yields B
  4. 4. Results Twisted-spike weeder 2012 Straight-spike weeder 2013 PE herbicide Hand weeding 0 100 200 Time (seconds m-2 person-1) • Significant (P<0.001) time reductions observed with the rotary weeders and herbicide application compared to hand weeding Time savings compared to hand weeding (%) 2012 2013 Twisted-spike weeder 40 56 Straight-spike weeder 32 49 PE herbicide 88 97 • Time savings: 3256% (weeders),8897% (herbicide)
  5. 5. Results 2012, 21 DAT Twisted-spike weeder 2012, 42 DAT Straight-spike weeder 2013, 21 DAT PE herbicide 2013, 42 DAT Hand weeding • Weed biomass dw: o lower (P<0.05) in PE herbicide plots at 21 (both years) and 42 DAT (2013) 0 6 12 18 Weed dry weight (g m-2) • Rice grain yields: Twisted-spike weeder 2012 o 2012: no differences Straight-spike weeder 2013 o 2013 > 2012 PE herbicide Hand weeding 0 5 Yield (t ha-1) 10 o 2013: PE herbicide significant (P<0.05) higher than any other treatment
  6. 6. Discussion • Significant time savings with PE herbicide and rotary weeders on 48 m2 plots o implications for larger areas still unknown • Herbicide application: o yield and weed control advantage o knowledge intensive, market dependent, expensive; health/environmental risks • Rotary weeders: o no yield or weed control advantage, availability of weeders, row planting, manpower requires o relatively cheap and easy, compatible with IWM, GAP
  7. 7. Conclusions • Correct use of herbicides can reduce farmers’ time for weed management • Rotary weeders: more time- and manpowerdemanding than herbicides, but reduce weeding time by at least a third compared to hand weeding • Differences between weeders, hence they should be locally adapted • In the long run rotary weeders are more cost-effective, environmentally benign than herbicides • Suitable component technology for resource-poor rice farmers in SSA
  8. 8. Way forward • Agronomy o studying yield advantages, long-term effects o participatory on-farm rotary weeder tests in 11 countries • Mechanization o local adjustments o motorized rotary weeder o (more) blacksmith training workshops • Social science o impact on gender relations • Economics o economic analyses of weed management options • Phytopathology o effects of on disease spread
  9. 9. DVD Farmer-to-Farmer Instruction Videos on Effective and Labor-Saving Weed Management in Lowland Rice • 4 multi-language videos: o Effective weed management o Rice transplanting o Safe and correct use of herbicides o Using the rotary weeder in lowland rice • Technical drawings of rotary weeders and line-makers • Farmer training modules on Integrated Rice Management (PLAR-IRM) Copies available at the AfricaRice booth (this conference)
  10. 10. Thank you - Merci - Na som djita Hartelijk dank -ご静聴ありがとうございました

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