Soil organic matter and geochemical characteristics shape microbial community composition and structure across different land uses in an Australian wet tropical catchment

Abstract

Soil characteristics vary across land uses, and soil microbial communities are likely to respond to such variations. However, such responses are not well understood. In this study, we examined how specific changes in soil organic matter (SOM) and geochemical characteristics influenced the bacterial and fungal community composition and structure across land uses. Soil samples were collected from grazing, sugarcane, forest and banana land uses in the Johnstone River catchment (wet tropics), northeastern Australia. High-throughput sequencing of 16S rRNA gene and ITS amplicons were employed to characterise soil bacterial and fungal communities, respectively. Bacterial and fungal α-diversity did not differ across land uses, whereas strong shifts in their community composition and structure were evident. Patterns in microbial community composition were strongly (p < 0.01) associated with changes in soil total organic carbon and nitrogen (TOC and TN), TOC:TN ratio, hot-water extractable organic carbon (HWEOC) and soil geochemical characteristics (e.g., pH, Co, Mn, K, Mg and P contents). Distinct bacterial community composition was observed in forest soils, while fungal communities were similar in banana and forest soils compared with sugarcane and grazing. Overall, our results showed that SOM characteristics were the major driver on structuring soil microbial communities across land uses, while soil bacterial communities were more sensitive to variations in SOM and geochemical characteristics compared with fungi. Results from this study have implications for developing more targeted management practices across different land uses to improve soil health and ecosystem function in a wet tropical area.

Plant types shape soil microbial composition, diversity, function, and co‐occurrence patterns in cultivated land of a karst area

“…Maize soil had the highest content of OM (Figure 1a and Table S3), which might be due to the following aspects: (1) Plant types of roots, root exudates, plant residues, and litter in the soil. The soil organic matter is introduced mainly due to the decomposition of roots, root exudates, litter, and plant residues in the soil (Bahadori et al, 2022; Schmidt et al, 2011). Although maize (C 4 ) has greater carbon sequestration capacity than cabbage and cocozelle (C 3 ) (Vadez et al, 2021), maize litter and plant residues contain more carbon.…”

The origin of suspended particulate matter in the Great Barrier Reef

“…4a ). The biological component of SPM represented by microbial diversity and community structure (MDCS), consisting of bacterial and fungal richness (BactRich and FunRich), diversity (Shannon Index - BactShann and FunShann) and community structure (BactNMDS and FunNMDS) 33 , 34 . Our results showed that the shift in MDCS was highly correlated with the variation in environmental factors (Env2) and organic carbon characteristics (OCC) of the SPM across habitat types (Fig.…”

Enhancing phosphorus bioavailability in lateritic red soil: Combining Bacillus subtilis inoculated microbial organic fertilizer with reduced chemical input

“…The main differences among the three (bio) organic fertilizers were that NBW was inoculated with B. subtilis , and HLJ organic fertilizer had a higher organic matter content than CM. According to a previous report, SOM characteristics were the major drivers of soil microbial community structure, while soil bacterial communities were more sensitive to variations in SOM content than fungal communities (Bahadori et al., 2022). The variance partitioning analysis (VPA) suggest that microbial biological factors mainly promoted the transformation of P forms.…”