Application of biochar in estrogen hormone-contaminated and manure-affected soils: Impact on soil respiration, microbial community and enzyme activity

Authors: WEI, ZHUO - LSU Agcenter; WANG, JIM - LSU Agcenter; FULTZ, LISA - LSU Agcenter; White, Paul; JEONG, CHANGYOON - LSU Agcenter

Submitted to: Chemosphere
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/10/2020
Publication Date: 5/10/2021
Publication URL: https://handle.nal.usda.gov/10113/7148730
Citation: Wei, Z., Wang, J.J., Fultz, L.M., White Jr, P.M., Jeong, C. 2021. Application of biochar in estrogen hormone-contaminated and manure-affected soils: Impact on soil respiration, microbial community and enzyme activity. Chemosphere. 270. Article 128625. https://doi.org/10.1016/j.chemosphere.2020.128625.
DOI: https://doi.org/10.1016/j.chemosphere.2020.128625

Interpretive Summary: Biochar is a type of charcoal than can be added to soil to improve soil health or clean “dirty,” or “contaminated” soils. Hormones are chemicals that regulate, or control, important cells or tissues in plants and animals. Some of these hormones are used in livestock production to treat reproductive disorders. This study investigated what happens when biochar is added to soil that contains hormones due to the presence of animal manures. The biochar was produced from sugarcane leaves. The activity of soil microorganisms was determined during lab-scale experiments by measuring specific enzymes; microbial respiration was measured as well as identifying microorganisms based on their fatty acid profiles. Hormones stimulated microbial growth and respiration, but had little impact on microbial enzyme activity. Biochar acturally decreased microbial growth, respiration, and enzyme activity. Based on these results, biochar may decrease microbial activity and slow clean-up of hormones found in manure-impacted soils.

Technical Abstract: Biochar as a soil amendment has been proposed for enhancing carbon sequestration and manure-borne hormone contaminant remediation. However, little is known about the ecological risk of biochar application in the soil with hormone contamination. This study investigated the influence of biochar in three manure-impacted soils contaminated with estrogen hormones, natural estrogen 17ß-estradiol and synthesized estrogen 17a-ethinylestradiol in a microcosm experiment. Specifically, microbial respiration was periodically determined during microcosm incubation while microbial community phospholipid fatty acids and activities of nutrient (C, N, P, S) cycling related enzymes (glucosaminidase, urease, phosphodiesterase, arylsulphatase) were characterized after the incubation. Results showed that the manure-impacted soils with high SOC generally had greater total microbial biomass, ratios of fungi/bacteria and Gram-positive bacteria/Gram-negative bacteria, and phosphodiesterase activity, but lower urease activity. Additionally, hormones stimulated microbial respiration and biomass, while had little impact on activity of the enzymes. On the other hand, biochar showed negative priming effect by significantly decreasing total microbial biomass by 8.7%-26.4%, CO2 production by 16.6%-33.5%, and glucosaminidase activity by 27.1%-41.0% in the three soils. Biochar significantly increased the activity of phosphodiesterase, showed no impact on arylsulphatase, while decreased the activity of urease. Overall, the study suggests that when used in hormone remediation in manure-impact soils, biochar could improve phosphodiesterase and arylsulphatase, but may decrease soil microbial activity and the activity of soil glucosaminidase and urease.