Biological soil crusts and conservation agriculture soils

Authors: PETERMANN, BILLI - Texas Tech University; LEWIS, KATIE - Texas Agrilife; Acosta-Martinez, Veronica; SLAUGHTER, LINDSEY - Texas Tech University

Submitted to: ASA-CSSA-SSSA Annual Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 7/12/2021
Publication Date: 11/8/2021
Citation: Petermann, B., Lewis, K., Acosta Martinez, V., Slaughter, L. 2021. Biological soil crusts and conservation agriculture soils [abstract]. ASA-CSSA-SSSA Annual Meeting Abstracts.

Interpretive Summary:

Technical Abstract: Soil microbial communities drive many of the processes that influence nutrient cycling, improve soil structure and subsequent water dynamics. Biological soil crusts (BSC) are a conglomerate of cyanobacteria, micro-fungi, lichens, and moss that intertwines with the soil surface providing soil stabilization and important ecosystems services in regions with sparse vegetation such as semi-arid Texas Southern High Plains (SHP). Conventional row-crop production practices in this semi-arid region leave a large area of bare soil that increases susceptibility to wind and water erosion and could benefit from increased water-holding dynamics and structural stability provided by biocrust formation, yet these communities would be continually disturbed by tillage practices. Conservation practices such as no-tillage may potentially allow biocrust-forming microbial communities to become established. This study investigated the presence and activities of BSC-forming communities in two established long term (>7 years) agricultural production sites in the Texas SHP (Halfway and Lamesa) under conservation management. Surface scrapes (1 cm depth) were collected from bare areas between plants within each cropping system. BSC samples were collected from an undisturbed rangeland area in Muleshoe, Texas to determine the dominant microbial composition and utilized as the baseline for analysis. We analyzed the samples using ester-linked fatty-acid methyl esters (EL-FAMES), 16S and ITS sequencing to measure soil microbial biomass and community structure between treatments via non-metric multidimensional scaling (NMS) ordinations. Changes in microbial C, N and P-cycling activities were assessed using high-throughput fluorometric assays of extracellular enzymes, including ß-1, 4, glucosidase (BG), ß-1, 4, N-acetylglucosaminidase (NAG), leucine amino peptidase (LAP), and acid phosphatase (PHOS). We see similarities in some of the enzymatic activities, and 16S community structure, however the fungal communities that dominate each system (BSC, Ag soils) strongly separates these communities suggesting that even minimal disturbance with conservation agriculture is still enough to hinder the colonization of BSC-forming organisms.