Masters Theses

Date of Award

8-2025

Degree Type

Thesis

Degree Name

Master of Science

Major

Environmental and Soil Sciences

Major Professor

Sean M. Schaeffer

Committee Members

Daniel Yoder, Jie Zhuang, Ashlee Dere

Abstract

Investigating the impact intensively managed landscapes have on biotic-abiotic interfaces in the root zone is critical for understanding how intensive management affects microbial communities across the soil profile. The root zone comprises the soil-root-microbe system and is a hotspot of biogeochemical transformations. This critical interface regulates sub-surface biogeochemical environments as well as dynamics in the soil surface that are primarily influenced by management activities, such as artificial ditches, fertilizer applications, and tile drains. The soil’s “active root zone” is in reference to six depths: 0-10cm, 10-20cm, 20-30cm (upper active root zone), 55-65cm (lower active zone), and 105-115cm, 175-185cm (below the active root zone) within soil profiles from intensively managed systems and restored prairies in both Illinois and Nebraska. Hydrolytic enzyme activity is a technique used in microbial community studies to illustrate microbial community function while phospholipid fatty acid analysis is commonly used to identify the microbial community. Incorporating both together in addition to other abiotic and abiotic factors in the soil such as % sand, % clay, soil temperature, water content, AL2O3, nitrate, microbial biomass carbon (MBC), permanganate oxidizable carbon (POXC), and soil pH can assist in illustrating a more complete depiction of what is occurring across the active root zone between systems heavily impacted by anthropogenic activities and systems that are not. Results showed that restored prairies have overall higher microbial activity compared to intensively managed systems (p< 0.01). The management effects on enzyme activity were inconclusive for every enzyme except N-acetyl-β-glucosaminidase which was consistently higher in prairies. This suggests nutrient cycling differences between intensively managed systems and prairies, as demonstrated by enzymatic activity results. This suggests that intensive agriculture affects nutrient dynamics and carbon cycling which is reflected by the microbial community and their functionality.

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