Soil microbial response to long-term management practices in cotton systems of the texas southern high plains

Authors: PETERMANN, B - Texas Tech University; LEWIS, K - Texas Tech University; Acosta-Martinez, Veronica; SHARMA, J - Texas Tech University; STEFFAN, J - Dickinson State University; SLAUGHTER, L - Texas Tech University

Submitted to: ASA-CSSA-SSSA Annual Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 8/21/2019
Publication Date: 11/12/2019
Citation: Petermann, B.J., Lewis, K., Acosta Martinez, V., Sharma, J., Steffan, J.J., Slaughter, L.C. 2019. Soil microbial response to long-term management practices in cotton systems of the texas southern high plains. ASA-CSSA-SSSA Annual Meeting Abstracts. 1.

Interpretive Summary:

Technical Abstract: Agricultural producers in semi-arid regions such as the Texas Southern High Plains (SHP) face many challenges while attempting to increase soil health and profitability, particularly including severe water and nutrient scarcity. Cotton production in the semi-arid Texas SHP has historically relied on continuous cropping, tillage, and irrigation to sustain productivity, yet declining water resources have prompted a greater focus on conservation management practices such as cover crops, crop rotations, and no-tillage to improve soil health and water storage. Because soil microbial biomass and community structure drive many of the processes that influence plant productivity, such as nutrient cycling and improvement of soil structure and subsequent water dynamics, microbial structure and function are important indicators that can be used to assess soil health improvements. We investigated soil and rhizosphere microbial community structure and function at two sites in the Texas SHP (Halfway and Lamesa) under three long-term (> 7 years) established cotton production management strategies: 1) Continuous mono-crop with conventional tillage, 2) no-till with winter rye cover crop, and 3) no-till with a cotton/winter wheat rotation. Bulk soil samples from two depth increments (0-5 cm and 5-10 cm) and from rhizosphere samples were analyzed using ester-linked fatty-acid methyl esters (EL-FAMES) to measure soil microbial biomass, and selected lipid biomarkers were used to characterize microbial community structure between treatments and depths via non-metric multidimensional scaling (NMS) ordinations. Changes in microbial C and N-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). Our results revealed management-induced differences in biological soil health indicators and associated soil properties such as organic matter, suggesting that conservation management practices including no-till and diversified planting may improve soil health in semi-arid agricultural regions such as the Texas SHP.