Halophyte residue decomposition and microbial community structure in coastal soil

Abstract

AbstractSaltmarshes are known for higher primary productivity and play a crucial role in carbon‐sequestration, nutrient‐cycling, and ecological services; however, scarce information are available on halophyte residue mineralization and microbial community structure during decomposition. Soil microcosms with residues (1% w/w) of three dominant halophytes (Aeluropus lagopoides, Arthrocnemum indicum, and Suaeda nudiflora) and one control were incubated under laboratory conditions and sampled at 1, 5, 10, 20, 40, and 90 days to link the microbial community structure and residues decomposition in degraded coastal soil. Samples were subjected to identification of active microbial groups and residue mineralization using fatty acid methyl ester (FAME) and CO2 evolution methods, respectively. Biochemical composition of residues was also analyzed. Cumulative CO2 evolution was elevated in residue‐amended soils compared with control, and it was highest in Arthrocnemum followed by Suaeda, Aeluropus, and control soil. The Aeluropus residue decomposed slower than others due to its high C/N ratio and low protein content. The contents of total FAME and biomarker FAMEs of microbial groups (bacterial, fungal, and actinomycetes) responded positively to the residue amendments compared with control, which indicate the improvement in soil microbial biomass. Soils amended with Suaeda had the highest amount of total (76.8 nmol/g) and fungal FAMEs (6.7 nmol/g), and bacterial (28.6 nmol/g) and actinomycete (3.0 nmol/g) FAMEs were elevated in Arthrocnemum amended soil. At the same time, soils amended with Suaeda (6.2%), Arthrocnemum (28.4%), and control (15.4%) had the greatest abundance of fungal, Gram‐negative and Gram‐positive FAME biomarkers, respectively. The present study suggests that residue of halophyte species affected the abundance of fungal and bacterial biomarkers, and the microbial community structure.