Soil microbial biomass and composition from urban landscapes in a semiarid climate

Authors: SAPKOTA, MANISH - Texas Tech University; YOUNG, JOSEPH - Texas Tech University; SLAUGHTER, LINDSEY - Texas Tech University; Acosta-Martinez, Veronica; COLDREN, CADE - Texas Tech University

Submitted to: Applied Soil Ecology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/19/2020
Publication Date: 2/1/2021
Citation: Sapkota, M., Young, J., Slaughter, L., Acosta Martinez, V., Coldren, C. 2021. Soil microbial biomass and composition from urban landscapes in a semiarid climate. Applied Soil Ecology. 158. https://doi.org/10.1016/j.apsoil.2020.103810.
DOI: https://doi.org/10.1016/j.apsoil.2020.103810

Interpretive Summary: Soil microbes are important indicators of soil health and are related to soil water conservation. However, little is known about the microbes under turfgrass in semiarid regions. Turfgrass will become more important as more homeowners and cities become water limited due climate variability and competition with other uses. Researchers from Texas Tech University and USDA-ARS in Lubbock TX evaluated soil microbes in yards of homes of different age. The study found more soil microbes in older homes with greater soil bacteria populations but little change in soil fungi populations. Differences in how the turfgrass were managed (fertilizer, amount of water) did not affect soil microbes. The study indicates that turfgrass sustain microbes and their essential functions in soil even low input of water and chemicals.

Technical Abstract: Soil microbial communities have been used as indicators of changes in soil health agroecosystems. However, few studies have evaluated soil health under turfgrass systems especially in semiarid climates. Our study determined whether microbial biomass and composition in residential soils were controlled by home age along a turfgrass chronosequence and evaluated effects of turfgrass management in structuring soil microbial communities. Soil samples were obtained from nine locations within each home age category: oldest (1950–1970), middle (1971–1990), newer (1991–2010), and newest (2011–present) in summer 2018 and 2019. Soil microbial biomass and composition were assessed using chloroform fumigation extraction method (CFEM) and ester-linked fatty acid methyl ester (EL-FAME) analysis. Soil microbial biomass carbon (MBC) and nitrogen (MBN) were 46–52% and 65–75% higher in oldest homes when compared to newest homes, respectively. Neither total FAMEs nor fungal FAME abundance differed for home age categories, but bacterial FAME abundance increased with home age. Non-parametric analysis determined no microbial abundance differences with management practices or turfgrass species. Pearson correlations indicated soil organic matter and silt content most consistently altered the microbial community. Soil microbial communities within semiarid, urban environments shifted from high fungal to bacterial dominated as landscapes matured, potentially due to long-term effects of irrigation, fertilization, and pesticide use. Our results indicate time after establishment was more important to development of soil microbial communities in semiarid, perennial turfgrass systems than subtle differences in management, suggesting soil health and resource conservation goals in this setting may be achievable with relatively low levels of management over time.