Relationships Between Soil Microorganisms, Plant Communities, and Soil Characteristics in Chinese Subtropical Forests

Abstract

We analyzed the influence of above-and belowground factors on the soil microbial community in a Chinese subtropical forest, one of the most diverse biomes in the northern hemisphere. Soil samples were taken at different depths from four replicate comparative study plots in each of three forest age classes (young 10-40 years, medium 40-80 years, old ‡80 years). Microbial biomass and community structure were then determined using phospholipid fatty acid (PLFA) analysis, and basal respiration and microbial biomass carbon (C mic ) were determined by substrate-induced respiration.These data were then related to plant community and soil variables using non-metric multidimensional scaling analysis and post-hoc permutational correlations. We found that microbial lipid composition and abundance were not related to forest age class. Instead, microbial lipid composition and abundance were related to factors reflecting primary production, i.e., percent litter cover, percent dead wood cover, and percent tree layer cover. Specifically, the relative abundance (mol fraction) of indicators for arbuscular mycorrhizal fungi, Gram-positive and Gram-negative bacteria were positively significantly correlated with percent litter cover. We also found that the biomass of all microbial groups and total PLFA were negatively significantly related to percent deadwood cover. In addition, pH H 2 O was the only soil parameter that was correlated significantly to microbial biomass. Our results indicate that overarching ecological factors such as plant productivity and soil pH are important factors influencing the soil microbial community, both in terms of biomass and of community composition in this subtropical ecosystem.

Post-Fire Spatial Patterns of Soil Nitrogen Mineralization and Microbial Abundance

“…In this study, the fungi-to-bacteria ratio was negatively related to net N mineralization rates, which may simply indicate the importance of total bacterial abundance [53] in governing N cycling activity, although differences in C:N between fungi and bacteria and their relative dominance cannot be discounted [55]. Other factors such as pH and charcoal are generally considered important for influencing post-fire N cycling [41], [56], [57]. Soil pH ranged from 4.58 to 5.44 (average 4.9±0.2 (±1 SE)), not significantly different than that in mature stands in the GYE (5.1, [41]) indicating that fire resulted in few differences in soil pH at the plot level two years following fire.…”

The rhizospheric microbial community structure and diversity of deciduous and evergreen forests in Taihu Lake area, China

“…All of the homogenized soil samples were immediately sieved (2 mm mesh) in the field to remove stones and roots, and then transferred to sterile iceboxes, stored at -20°C until molecular analysis. The soil characteristics were determined from the residual soil samples after molecular analysis by referring to the methods of Wu et al (2012) [37]. …”

Seasonal differences in tree species' influence on soil microbial communities

“…Litterfall in autumn provides large amounts of nutrients and energy for soil microorganisms in the topsoil, and the abundance of these microorganisms is strongly related to the amount of litter input (Prevost-Boure et al, 2011;Wu et al, 2012). In autumn 2005, the total amount of fallen litter (g DM m À2 ) on our study plots was quite similar for DL 2 and DL 3 (391 AE 37.1 and 393 AE 59.4) and only slightly lower in DL 1 (324 AE 21.6) (Jacob et al, 2010a).…”

“…Additionally, both the quantity and quality of litter affect both the predators and the decomposer macrofauna (Weland, 2009). Studies that have investigated the relationships between plant species diversity and soil microbial communities using PLFA profiles in grasslands (Habekost et al, 2008;Breulmann et al, 2012) and in forests (Hackl et al, 2005;Merilä et al, 2010;Brockett et al, 2012;Wu et al, 2012;Myers et al, 2001) have underlined the importance of the quantity and quality of organic resources as well as abiotic factors such as soil pH, soil texture and soil moisture for the soil microbial community.…”