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Beneath the Surface: Investigating soil microbial communities and enzyme activities in a Canfield silt loam under various tillage and fertilizer management systems

Applied Research

Heather Neikirk
Extension Educator
Ohio State University Extension
Massillon

Abstract

With increasing costs of inputs, many small farmers are focusing more on soil health to maintain yields and profitability while decreasing inputs. Part of a healthy soil is a diverse and active soil microbial community.  In 2021, soil biological measurements were assessed in the Stark Sustainable Soil Initiative through funding from the Paul C. and Edna H. Warner Endowment Fund for Sustainable Agriculture provided through The Ohio State University Agro-Ecosystems Program.  Soil microbial community analysis was determined through the fatty-acid methyl ester (FAME) method and potential soil enzyme activity was determined through assessment of three enzymes: N-acetyl-glucosaminidase (NAGase), a carbon and nitrogen cycling enzyme, acid phosphastase (Acid_P), a phosphorus cycling enzyme, and β-glucosidase (B_Glucos), a carbon cycling enzyme. These measurements were taken across eleven farms in Stark County (Northeastern), Ohio, with the same soil type but varying management techniques (i.e. tillage, fertilizer, etc.) at the 0-15 cm (6 inches) depth. Results revealed that hay fields had greater measurable soil health indicators than all cultivated fields, but there was no difference among tillage methods in cultivated fields [No-till (NT), Disc-chisel (DC), Mold-board plow (MP)].   In total microbial abundance, the Hayfields averaged 297 nmol g-1 while the cultivated fields averaged 158 nmol g-1, a 61% difference. There was a 57% greater NAGase activity and 65% greater Acid_P activity in Hayfields compared to cultivated fields but no difference in B_Glucos activity. However, while potential soil enzyme activity increased with increasing microbial population, there was a strong correlation between enzymes and substrates. Correlation analysis revealed a strong positive relationship between organic matter (LOI) and NAGase (r=0.66) and LOI and B_Glucos (r=0.37). These results suggest that increasing soil organic matter may reduce synthetic fertilizer inputs by providing soil microorganisms the substrates needed for enzyme activity and increased release of plant available nutrients.

Poster has NOT been presented at any previous NACAA AM/PIC

This poster is being submitted only for display at AM/PIC. Poster is not to be judged, but the abstract will be published in the proceedings.

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Authors: Heather A. Neikirk, Dr. Kathleen M. Bridges, Dr. Rattan Lal
  1. Neikirk, H. Extension Educator, Agriculture and Natural Resources, Ohio State University Extension Stark County, Ohio, 44646
  2. Bridges, D. Postdoctoral Scholar, Rattan Lal Carbon Management and Sequestration Center (CMASC), The Ohio State University, Ohio, 44646
  3. Lal, D. Distinguished Professor of Soil Science and Director, Rattan Lal Carbon Management and Sequestration Center, The Ohio State University, Ohio, 43210