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Date of Award
Department or Program Affiliation
Master of Arts (MA)
Bach, Andrew J.
LaHue, Deirdre Griffin
I sampled Skagit silt loam soils from a field trial at the WSU NWREC where biochar and compost were added to potato crops in late spring pre-planting. Soil mesofauna were sampled at mid and late-summer, while soil microbes were sampled at late summer exclusively. Soil treatments included mixed biochar and compost, compost-only, and an unamended control. Mesofauna were extracted with Berlese funnels and sorted to functional groups. F:B ratios and total microbial C were determined using microbiometer test kits. To test whether biochar and compost induced changes to soil mesofauna communities, I used permutational ANOVA. Differences in F:B ratios and total microbial C were tested using a linear mixed effects model with ANOVA. Mesofauna communities differed markedly between mid and late-summer sampling (p=0.001) with a shift from Rhyzoglyphus, and Collembola dominance to a more even mix of functional groups including Formicidae, Psocodea, Symphyla, Apocrita, and Diptera with a diminished overall population. However, neither compost nor biochar treatments had a significant effect on soil mesofauna communities (p=0.291) nor did they alter F:B ratios and total microbial C (p=0.246 and 0.787 respectively). The microbial community favored bacterial dominance with an average F:B ratio of 0.60±0.21 across treatments and total microbial C was 272.50 µg C/g±115.82. The decrease in mesofauna abundance between mid and late summer likely reflects seasonal changes in mesofauna activity due to differences in soil temperature and moisture levels. The F:B ratio favoring bacterial dominance is indicative of chemical fertilizer use and heavy tillage which favors fast growing bacterial groups.
Biochar, compost, microbes, mesofauna, Skagit, F:B ratio, mites
Western Washington University
Subject – LCSH
Silt loam--Skagit River Valley (B.C. and Wash.); Soil invertebrates--Skagit River Valley (B.C. and Wash.); Biochar--Skagit River Valley (B.C. and Wash.); Compost--Skagit River Valley (B.C. and Wash.)
Skagit River Valley (B.C. and Wash.)
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Goff, Jameson, "Soil Mesofauna and Microbial Community Response to Mixed Biochar and Compost Application in a Skagit Silt Loam" (2022). WWU Graduate School Collection. 1138.