Thesis
Improving the yields of late-planted winter wheat with seeding rate and phosphorus fertility
Washington State University
Master of Science (MS), Washington State University
2009
Handle:
https://hdl.handle.net/2376/102540
Abstract
Dryland wheat producers in the low rainfall zone (<450 mm annual precipitation) of eastern Washington commonly utilize winter wheat-tillage fallow rotations. Annual cropping or chemical fallow reduces wind erosion in this susceptible area. However, late seeding is required in these situations due to a lack of seed zone moisture at normal planting times. The objective of this study was to determine if phosphorus (P) fertility and/or seeding rates can be altered to improve late seeded recrop or chemical fallow winter wheat yields. Winter wheat was grown at five locations in eastern Washington in 2004-05 and three locations in 2005-06. One site was in chemical fallow and the others recropped into standing winter wheat stubble. In the first year two sites were abandoned due to pest invasions while in the second year one site was abandoned due to volunteer wheat contamination. Seeding rates were 45 and 78 kg ha-1. Phosphorus rates were 0, 22, 45, 67, and 90 kg ha-1 P2O5 in 2004-05, and 0, 11, 22, 45, and 67 kg ha-1 P2O5 in 2005-06. The chemical fallow site had both early and late seeding dates while the recrop sites had only late seeding dates. Measurements included stand density, dry matter accumulation and partitioning, grain yield, yield components, and total P uptake. Averaged across seeding rates, grain yield at recrop sites increased linearly with P rate (0.7 and 1.6 kg grain kg-1 P2O5 applied in 2004-05; 3.9 kg grain kg-1 P2O5 applied in 2005-06). The yield response to P at the chemical fallow site was quadratic in 2004-05, compared to a linear response with the 45 kg ha-1 seed rate and no response to P with the 78 kg ha-1 seed rate in 2005-06. At the chemical fallow site, yield for the early seeding date was 289 kg ha-1 (9.8%) higher than the late seeding date in 2004-05, and 865 kg ha-1 (30.6%) lower than late seeding in 2005-06 due to unfavorable seed zone moisture at early planting. Phosphorus increased yields of recrop and chemical fallow winter wheat; however, seeding date and rate showed variable responses depending on year.
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Details
- Title
- Improving the yields of late-planted winter wheat with seeding rate and phosphorus fertility
- Creators
- Eric D. Harwood
- Contributors
- Richard T. Koenig (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
- 99900525089001842
- Language
- English
- Resource Type
- Thesis