Thesis
FLUID LIME TRANSPORT IN NO-TILL SYSTEMS: EFFECTS ON SOIL pH, MICROBIAL ACTIVITY, AND CROP PERFORMANCE
Master of Science (MS), Washington State University
2026
Abstract
Stratified soil acidity caused by repeated applications of ammonium-based fertilizers is a persistent constraint in no-till cropping systems of the inland Pacific Northwest. This study evaluated the effects of subsurface fluid lime on soil pH, carbonate-derived carbon, root-associated microbial communities, and crop performance during a three-year crop rotation consisting of Austrian winter pea (Pisum sativum), spring canola (Brassica napus), and winter wheat (Triticum aestivum). Soil responses were evaluated using depth-resolved pH measurements, δ¹³C as a tracer of carbonate-derived carbon, and phospholipid fatty acid (PLFA) analysis, while crop performance was assessed through grain yield and quality measurements. Subsurface fluid lime increased soil pH, with the largest responses occurring within the upper 10 cm of the soil profile. Changes in δ¹³C indicated the presence of carbonate-derived carbon within the sampled profile, although its distribution varied among landscape positions. Microbial responses were more evident for arbuscular mycorrhizal fungi than for total fungal biomass. Crop responses varied among species and years. Significant treatment effects were observed for canola oil concentration and wheat grain protein concentration, whereas pea yield, pea protein concentration, canola yield, and wheat yield showed no consistent response to liming. Landscape position consistently influenced microbial biomass and crop performance across the study. Overall, subsurface fluid lime effectively increased soil pH under no-till management, but biological and agronomic responses varied with landscape position and did not consistently translate into improved crop performance during the three-year study.
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Details
- Title
- FLUID LIME TRANSPORT IN NO-TILL SYSTEMS: EFFECTS ON SOIL pH, MICROBIAL ACTIVITY, AND CROP PERFORMANCE
- Creators
- Leah Amazing Brown Chidziwe
- Contributors
- Joao A Antonangelo (Advisor)Joaquin J Casanova (Committee Member)Claire L Phillips (Committee Member)Richard T Koenig (Committee Member)
- Awarding Institution
- Washington State University
- Academic Unit
- Department of Crop and Soil Sciences
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Number of pages
- 153
- Identifiers
- 99901417206401842
- Language
- English
- Resource Type
- Thesis