Soil Science Seminar on Wednesday, 31 October, 2018 will be presented by Qing Xia, Soil Science PhD Student, Crop & Soil Science Department, NCSU.

Title: “Effects of Soil Texture on Microbial Assemblages and Interactions”

Pre-seminar refreshments are served at 3:15 pm in the McKimmon Room (2223 WMS). Seminar begins at 3:40 pm in Williams Hall Auditorium (2215 WMS). Everyone is welcome to attend.

Abstract

Soil texture is known to affect soil pore size distribution, water network connectivity, and nutrient availability, and yet few have studied its impacts on the soil microbial community. This work aimed to examine how soil texture shaped the diversity, composition, and function of the soil microbial community. Soil cores (5 cm in diameter and 10 cm depth) were taken from 12 bermudagrass golf courses across North Carolina. The soil textures covered by the sites included loamy sand, sandy loam, loam, sandy clay loam, sandy clay, clay loam, and clay. For interpretation purpose, soils were separated into three groups according to sand percentage: clayey (30-53%), loamy (54-71%), and sandy group (71.3-83%). After incubation of soil cores at different moisture contents (control, air-dried, and saturated), we had both bacterial and fungal DNA sequenced and measured soil physical biochemical properties. Our data showed that soil texture did affect the soil microbial community composition, but the effect was moderate. Both bacterial and fungal community composition tended to cluster within texture groups. Influences of soil properties on microbial communities varied with texture groups. Soil organic C and N accounting for <10%, 12%, and 27% of total variation in bacterial communities in sandy, loamy, and clayey groups respectively, indicating an increasing importance of soil organic matter in shaping microbial communities in clayey soils. Relative abundance of major bacterial and fungal taxonomic groups could be characterized by increasing, decreasing, or curvilinear trend lines in relation to soil sand percentage. Genetic diagnose for N cycling showed that texture also affected soil N processes, where a higher sand percentage resulted in increasing potential in denitrification and N fixation. This work may provide better guidance in texture-based bacterial and fungal mapping and soil management.