scholarly journals Effect of Soil Layer and Plant–Soil Interaction on Soil Microbial Diversity and Function after Canopy Gap Disturbance

Forests ◽  
2018 ◽  
Vol 9 (11) ◽  
pp. 680 ◽  
Author(s):  
Xuan Yu ◽  
Lin Yang ◽  
Shixuan Fei ◽  
Zitong Ma ◽  
Ruqian Hao ◽  
...  

Gaps by thinning can have different microclimatic environments compared to surrounding areas, depending on the size of the gap. In addition, gaps can play important roles in biological dynamics, nutrient cycling, and seedling regeneration. The impacts of gap size on soil microbial communities and enzyme activities in different soil layers in Chinese pine plantations are not well understood. Here, we created gaps of 45 m2 (small, G1), 100 m2 (medium, G2), and 190 m2 (large, G3) by thinning unhealthy trees in an aged (i.e., 50 years old) monoculture Chinese pine plantation in 2010. Soil samples were collected in 2015. The total, bacterial, Gram-positive (G+), and Gram-negative (G−) phospholipid fatty acid (PLFA) profiles were highest in medium gaps in both the organic and mineral layers. These indicesdecreased sharply as gap size increased to 190 m2, and each of the detected enzyme activities demonstrated the same trend. Under all the gap size managements, abundances of microbial PLFAs and enzyme activities in the organic layers were higher than in the mineral layers. The soil layer was found to have a stronger influence on soil microbial communities than gap size. Redundancy analysis (RDA) based on the three systems with different gap sizes showed that undergrowth coverage, diversity, soil total nitrogen (TN), total organic carbon (TOC), and available phosphorus (AT) significantly affected soil microbial communities. Our findings highlighted that the effect of gap size on soil microenvironment is valuable information for assessing soil fertility. Medium gaps (i.e., 100 m2) have higher microbial PLFAs, enzyme activity, and soil nutrient availability. These medium gaps are considered favorable for soil microbial communities and fertility studied in a Chinese pine plantation managed on the Loess Plateau.

2018 ◽  
Vol 15 (4) ◽  
pp. 1217-1228 ◽  
Author(s):  
Zhiwei Xu ◽  
Guirui Yu ◽  
Xinyu Zhang ◽  
Nianpeng He ◽  
Qiufeng Wang ◽  
...  

Abstract. Soil microorganisms play an important role in regulating nutrient cycling in terrestrial ecosystems. Most of the studies conducted thus far have been confined to a single forest biome or have focused on one or two controlling factors, and few have dealt with the integrated effects of climate, vegetation, and soil substrate availability on soil microbial communities and functions among different forests. In this study, we used phospholipid-derived fatty acid (PLFA) analysis to investigate soil microbial community structure and extracellular enzymatic activities to evaluate the functional potential of soil microbes of different types of forests in three different climatic zones along the north–south transect in eastern China (NSTEC). Both climate and forest type had significant effects on soil enzyme activities and microbial communities with considerable interactive effects. Except for soil acid phosphatase (AP), the other three enzyme activities were much higher in the warm temperate zone than in the temperate and the subtropical climate zones. The soil total PLFAs and bacteria were much higher in the temperate zone than in the warm temperate and the subtropical zones. The soil β-glucosidase (BG) and N-acetylglucosaminidase (NAG) activities were highest in the coniferous forest. Except for the soil fungi and fungi–bacteria (F/B), the different groups of microbial PLFAs were much higher in the conifer broad-leaved mixed forests than in the coniferous forests and the broad-leaved forests. In general, soil enzyme activities and microbial PLFAs were higher in primary forests than in secondary forests in temperate and warm temperate regions. In the subtropical region, soil enzyme activities were lower in the primary forests than in the secondary forests and microbial PLFAs did not differ significantly between primary and secondary forests. Different compositions of the tree species may cause variations in soil microbial communities and enzyme activities. Our results showed that the main controls on soil microbes and functions vary in different climatic zones and that the effects of soil moisture content, soil temperature, clay content, and the soil N ∕ P ratio were considerable. This information will add value to the modeling of microbial processes and will contribute to carbon cycling in large-scale carbon models.


2017 ◽  
Author(s):  
Zhiwei Xu ◽  
Guirui Yu ◽  
Xinyu Zhang ◽  
Nianpeng He ◽  
Qiufeng Wang ◽  
...  

Abstract. Soil microorganisms play an important role in regulating nutrient cycling in terrestrial ecosystems. Most of the studies conducted thus far have been confined to a single forest biome or have focused on one or two controlling factors, and few have dealt with the integrated effects of climate, vegetation, and soil substrate availability on soil microbial communities and functions among different forests. In this study, we used phospholipid-derived fatty acid (PLFA) analysis to investigate soil microbial community structure, and extracellular enzymatic activities to evaluate the functional potential of soil microbes of different types of forests in three different climatic zones along the North-South transect in eastern China (NSTEC). In general, soil enzyme activities and microbial PLFAs were higher in primary forests than in secondary forests in temperate and warm temperate regions. In the subtropical region, soil enzyme activities were lower in the primary forests than in the secondary forests and microbial PLFAs did not differ significantly between primary and secondary forests. The microbial PLFAs and enzyme activities differed considerably between broadleaved and coniferous forests. Different species of coniferous trees may cause variations in soil microbial PLFAs and enzyme activities. Both climate and forest type had significant effects on soil enzyme activities and microbial communities with a considerable interactive effect. Litter nutrients made an important contribution to variations in the soil microbial communities and enzyme activities in temperate zones, while soil micro-climate and nutrients were the main controls on the soil microbial community structure and enzymatic activities in warm temperate and subtropical zones. Our results indicate that the main controls on soil microbes and functions vary across forest ecosystems in different climatic zones, and that the effects of soil moisture content, soil temperature, and the soil N/P ratio were considerable. This information will add value to modeling of microbial processes and will contribute to carbon cycling in large-scale carbon models.


2015 ◽  
Vol 12 (13) ◽  
pp. 10359-10387 ◽  
Author(s):  
W. Y. Dong ◽  
X. Y. Zhang ◽  
X. Y. Liu ◽  
X. L. Fu ◽  
F. S. Chen ◽  
...  

Abstract. Nitrogen (N) and phosphorus (P) additions to forest ecosystems are known to influence various above-ground properties, such as plant productivity and composition, and below-ground properties, such as soil nutrient cycling. However, our understanding of how soil microbial communities and their functions respond to nutrient additions in subtropical plantations is still not complete. In this study, we added N and P to Chinese fir plantations in subtropical China to examine how nutrient additions influenced soil microbial community composition and enzyme activities. The results showed that most soil microbial properties were responsive to N and/or P additions, but responses often varied depending on the nutrient added and the quantity added. For instance, there were more than 30 % greater increases in the activities of β-Glucosidase (βG) and N-acetyl-β-D-glucosaminidase (NAG) in the treatments that received nutrient additions compared to the control plot, whereas acid phosphatase (aP) activity was always higher (57 and 71 %, respectively) in the P treatment. N and P additions greatly enhanced the PLFA abundanceespecially in the N2P treatment, the bacterial PLFAs (bacPLFAs), fungal PLFAs (funPLFAs) and actinomycic PLFAs (actPLFAs) were about 2.5, 3 and 4 times higher, respectively, than in the CK. Soil enzyme activities were noticeably higher in November than in July, mainly due to seasonal differences in soil moisture content (SMC). βG or NAG activities were significantly and positively correlated with microbial PLFAs. There were also significant relationships between gram-positive (G+) bacteria and all three soil enzymes. These findings indicate that G+ bacteria is the most important microbial community in C, N, and P transformations in Chinese fir plantations, and that βG and NAG would be useful tools for assessing the biogeochemical transformation and metabolic activity of soil microbes. We recommend combined additions of N and P fertilizer to promote soil fertility and microbial activity in this kind of plantation.


2019 ◽  
Vol 85 (6) ◽  
Author(s):  
Shuo Jiao ◽  
Weimin Chen ◽  
Gehong Wei

ABSTRACT A lack of knowledge of the microbial responses to environmental change at the species and functional levels hinders our ability to understand the intrinsic mechanisms underlying the maintenance of microbial ecosystems. Here, we present results from temporal microcosms that introduced inorganic and organic contaminants into agro-soils for 90 days, with three common legume plants. Temporal dynamics and assemblage of soil microbial communities and functions in response to contamination under the influence of growth of different plants were explored via sequencing of the 16S rRNA amplicon and by shotgun metagenomics. Soil microbial alpha diversity and structure at the taxonomic and functional levels exhibited resilience patterns. Functional profiles showed greater resilience than did taxonomic ones. Different legume plants imposed stronger selection on taxonomic profiles than on functional ones. Network and random forest analyses revealed that the functional potential of soil microbial communities was fostered by various taxonomic groups. Betaproteobacteria were important predictors of key functional traits such as amino acid metabolism, nucleic acid metabolism, and hydrocarbon degradation. Our study reveals the strong resilience of the soil microbiome to chemical contamination and sensitive responses of taxonomic rather than functional profiles to selection processes induced by different legume plants. This is pivotal to develop approaches and policies for the protection of soil microbial diversity and functions in agro-ecosystems with different response strategies from global environmental drivers, such as soil contamination and plant invasion. IMPORTANCE Exploring the microbial responses to environmental disturbances is a central issue in microbial ecology. Understanding the dynamic responses of soil microbial communities to chemical contamination and the microbe-soil-plant interactions is essential for forecasting the long-term changes in soil ecosystems. Nevertheless, few studies have applied multi-omics approaches to assess the microbial responses to soil contamination and the microbe-soil-plant interactions at the taxonomic and functional levels simultaneously. Our study reveals clear succession and resilience patterns of soil microbial diversity and structure in response to chemical contamination. Different legume plants exerted stronger selection processes on taxonomic than on functional profiles in contaminated soils, which could benefit plant growth and fitness as well as foster the potential abilities of hydrocarbon degradation and metal tolerance. These results provide new insight into the resilience and assemblage of soil microbiome in response to environmental disturbances in agro-ecosystems at the species and functional levels.


Chemosphere ◽  
2016 ◽  
Vol 142 ◽  
pp. 145-152 ◽  
Author(s):  
Khalid A. Elzobair ◽  
Mary E. Stromberger ◽  
James A. Ippolito ◽  
Rodrick D. Lentz

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