Purpose: The objective of this study was to determine physical and/or microbial factors affecting the survival of Lm in different soil types.
Methods: The survival of two Lm strains in three soils under different management practice, (i.e., conventional agriculture (F1), fallowed for five years (F2), and uncultivated grassland (F3)), was monitored through daily spread plating on PALCAM agar. Soils were sampled from the soil surface (0-15 cm depth) and analyzed for a suite of physical and chemical properties. Microbial biodiversity analysis was conducted using high throughput sequencing (HTS) of 16s rDNA extracted from each soil sample.
Results: Area under the curve analysis revealed greater survival capacity for both Lm strains in F3 compared to F1 and F2 (Fisher’s LSD, P < 0.05). Moisture content was found to be significantly different (Fisher’s LSD, P = 0.001) between all three soils at 7.2%, 8.9%, and 10.2% for F1, F2, and F3, respectively, and F3 was significantly higher (Fisher’s LSD, P < 0.001) in nitrogen at 25.3% compared to 13.5% and 21.2% for F1 and F2, respectively. Based on HTS data analysis, total reads were found to be higher in F1 compared to both F2 and F3 (Fisher’s LSD, P = 0.021); however, at the phylum level, F3 was found to have a higher proportion of Proteobacteria (28.7%; Fisher’s LSD, P = 0.003) and a lower proportion of Acidobacteria (8.7%; Fisher’s LSD, P< 0.001) compared to both F1 (24.3% and 21.9%, respectively) and F2 (24.2% and 19.9%, respectively).
Significance: These results add to the current understanding of factors that may affect the risk of Lm occurrence and survival in soil environments.