Thesis
The critical period of weed control in chickpea and lentil
Washington State University
Master of Science (MS), Washington State University
2010
Handle:
https://hdl.handle.net/2376/100852
Abstract
Four studies were conducted near Pullman, WA in 2008 and 2009 to determine the critical period of weed control (CPWC) in chickpea and lentil. Field trials were kept free of weeds for periods of 0, 14, 25, 35, 45, 60, 75, or ~90 days after emergence (DAE), or weeds were allowed to grow before removal for periods of 0, 14, 25, 35, 45, 60, 75, or ~90 DAE. Averaged across two varieties, weedy control treatments of lentil had 29.5% and 32% less seed yield than weed-free treatments during 2008 and 2009, respectively. When measured at crop maturity, 5.68 g/m2 of dry weed biomass resulted in 1% loss in lentil seed yield. Based on a 5% yield loss threshold, the CPWC for lentil was estimated to be 270 to 999 growing degree days (GDD) (base 1.5ºC, max 30ºC), 22 to 57 DAE, and crop growth stage V7 to the early pod stage during 2008. In 2009, a very short CPWC (624 to 650 GDD) was observed. Weed populations were composed mainly of mayweed chamomile, prickly lettuce, and spiny sowthistle. Spiny sowthistle emerged and competed with the lentil crop up to 2 weeks later than mayweed chamomile, indicating that mayweed chamomile may be an earlier and stronger competitor than spiny sowthistle. Full season weed interference with 'Sierra' chickpea caused yield reductions of 45%. A 1% reduction in chickpea seed yield was caused for every 3.16 g/m2 of dry weed biomass. Crop yield, crop biomass, pod number, and 100 seed weight for 'Sierra' chickpeas were significantly different between years, but there was no year by treatment interaction. Therefore, data were combined over years. Based on a 5% yield loss threshold, the CPWC for the 'Sierra' chickpea was 16 to 26 DAE. Alternatively, the CPWC could be expressed as 162 to 256 GDD or the 9 to 13 node stage in terms of crop development. Crop yield, crop biomass, and 100 seed weight declined with an increasing duration of weed competition.
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Details
- Title
- The critical period of weed control in chickpea and lentil
- Creators
- Jamin A. Smitchger
- Contributors
- Ian Cristofer Burke (Degree Supervisor)Joseph P. Yenish (Degree Supervisor)
- Awarding Institution
- Washington State University
- Academic Unit
- Crop and Soil Sciences, Department of
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University; [Pullman, Washington] :
- Identifiers
- 99900525154101842
- Language
- English
- Resource Type
- Thesis