scholarly journals Responses of CO2 Emissions and Soil Microbial Community Structures to Organic Amendment in Two Contrasting Soils in Zambia

2021 ◽  
Author(s):  
Toru Hamamoto ◽  
Nhamo Nhamo ◽  
David Chikoye ◽  
Ikabongo Mukumbuta ◽  
Yoshitaka Uchida
Keyword(s):  
Microbial Community ◽  
Soil Carbon ◽  
Soil Microbial Community ◽  
Field Experiments ◽  
Organic Amendments ◽  
Sub Saharan Africa ◽  
Community Structures ◽  
Soil Microbial Community Structure ◽  
Soil C ◽  
Soil Microbial

Abstract In sub-Saharan Africa, efforts have been made to increase soil carbon (C) content in agricultural ecosystems, due to severe soil degradation. The use of organic materials is one of the realistic methods to recover soil C. However, the impacts of organic amendments on soil microbial community and C cycles under limited soil C conditions are still unknown. We conducted field experiments using organic amendments in two sites with contrasting C content in Zambia. At both sites, temporal changes of soil carbon dioxide (CO2) emissions, bacterial and archaeal community structures were monitored during crop growing season (126 days). The organic amendments increased CO2 emissions with increased bacterial and archaeal abundance in the Kabwe site, while no impacts were shown in the Lusaka site. We also observed larger temporal variability in soil microbial community structure in Kabwe than in Lusaka. These contrasting results between the two soils might be due to the gap in microbial community stability. However, organic amendments have a significant potential to enhance microbial abundance and consequently sequester soil C in the Kabwe site. Site-specific strategies are needed to deal with the issues of soil C depletion in drylands.

scholarly journals Soil Microbial Community and Its Interaction with Soil Carbon Dynamics Following a Wetland Drying Process in Mu Us Sandy Land

2020 ◽  
Vol 17 (12) ◽  
pp. 4199
Author(s):  
Huan He ◽  
Yixuan Liu ◽  
Yue Hu ◽  
Mengqi Zhang ◽  
Guodong Wang ◽  
...  
Keyword(s):  
Microbial Community ◽  
Microbial Biomass ◽  
Soil Carbon ◽  
Soil Microbial Community ◽  
Microbial Respiration ◽  
Clay Content ◽  
Soil Conditions ◽  
Drying Process ◽  
Soil Microbial Community Structure ◽  
Soil Microbial

Increasing drought globally is a severe threat to fragile desert wetland ecosystem. It is of significance to study the effects of wetland drying on microbial regulation of soil carbon (C) in the desert. In this study, we examined the impacts of wetland drying on microbial biomass, microbial community (bacteria, fungi) and microbial activity [basal microbial respiration, microbial metabolic quotient (qCO2)]. Relationships of microbial properties with biotic factors [litter, soil organic carbon (SOC), total nitrogen (TN), total phosphorus (TP)], abiotic factors (soil moisture, pH and clay content) and biological processes (basal microbial respiration, qCO2) were also developed. Results showed that the drying of wetland led to a decrease of soil microbial biomass carbon (MBC) content, microbial biomass nitrogen (MBN) content and fungi and bacterial abundance, and an increase of the fungi:bacteria ratio. Wetland drying also led to increased soil basal respiration and increased qCO2, which was attributed to lower soil clay content and litter N concentration. The MBC:SOC ratios were higher under drier soil conditions than under virgin wetland, which was attributed to stronger C conserve ability of fungi than bacteria. The wetland drying process exacerbated soil C loss by strengthening heterotrophic respiration; however, the exact effects of soil microbial community structure on microbial C mineralization were not clear in this study and need further research.

scholarly journals Small-Scale Variability in the Soil Microbial Community Structure in a Semideveloped Farm in Zambia

2018 ◽  
Vol 2018 ◽  
pp. 1-6 ◽  
Author(s):  
Toru Hamamoto ◽  
Meki Chirwa ◽  
Imasiku Nyambe ◽  
Yoshitaka Uchida
Keyword(s):  
Land Use ◽  
Community Structure ◽  
Microbial Community ◽  
Microbial Community Structure ◽  
Soil Microbial Community ◽  
Sub Saharan Africa ◽  
Small Scale ◽  
Soil Microbial Community Structure ◽  
Soil Microbial ◽  
Sub Saharan

The conversion of natural lands into agricultural lands can lead to changes in the soil microbial community structure which, in turn, can affect soil functions. However, few studies have examined the effect of land use changes on the soil microbial community structure in sub-Saharan Africa. Therefore, the aim of this research was to investigate the relationships among soil characteristics and microbial communities in natural and agricultural ecosystems in a semideveloped lowland farm in the central region of Zambia, within which small-scale wetlands had been partly developed as watermelon (Citrullus lanatus) and/or maize (Zea mays) farms. We sampled soils from four different land use types within this farm: “native forest,” “grassland,” “watermelon farm,” and “maize farm.” We found that the land use type had a significant effect on the soil bacterial community structure at the class level, with the class Bacilli having significantly higher relative abundances in the forest sites and Gammaproteobacteria having significantly higher relative abundances in the maize sites than in the other land use types. These findings indicate that these bacterial classes may be sensitive to changes in soil ecosystems, and so further studies are required to investigate microbial indicators for the sustainable development of wetlands in sub-Saharan Africa.

scholarly journals The influence of soil microbial community structure on carbon and nitrogen partitioning in plant/soil ecosystems

2017 ◽  
Author(s):  
David C. Johnson
Keyword(s):  
Microbial Community ◽  
Soil Respiration ◽  
Soil Microbial Community ◽  
Cost Effective ◽  
Total Carbon ◽  
N Fixation ◽  
Soil Microbial Community Structure ◽  
Soil C ◽  
Soil Microbial ◽  
Initial Soil

A greenhouse study was conducted to evaluate the influence of increasing soil fungal-to-bacterial ratios (F:B) on the allocation of plant-photosynthate carbon into the carbon (C) and nitrogen (N) partitions (g) of plant components (root, shoot and fruit), New-Soil C and N, and Soil-Respiration C (CO2). Six (6) experimental treatment soils were formulated to provide linearly increasing: initial-soil C% (0.14% – 5.3%); initial-soil N% (0.01% - 0.40%); and soil microbial community (SMC) populations progressing from bacterial dominant (F:B=0.04) to fungal dominant (F:B=3.68) while still maintaining significant SMC population homogeneity. In an 86-day greenhouse experiment, growing chile plants (Capsicum annuum) in treatment soils with increasing F:B (0.4-3.68), the following was observed: a) a continuous linear increase (3% up to 56%) in the partitioning of total plant-photosynthate C into plant biomass (root, shoot and fruit) when regressed to initial F:B (m=0.13; r2=0.96); b) approximately 93% of the flow of plant-photosynthate C was partitioned into New-Soil C in Treatment 0 (F:B = 0.04), to a minimum of 47% in Treatment 5 (F:B = 3.68) demonstrating a negative linear correlation to treatment Initial-Soil C mass (m= -0.12; r2 = 0.97); c) conditional and coordinated flow of system C resources into nitrogen (N) fixation (est. C cost for N fixation at 6:1), with 1.21 g C partitioned to N fixation in Treatment 0 (F:B=0.04), peaking at 6.92 g C in Treatment 2 (F:B=1.6), and final C partitioning to N fixation of 2.91 g C in Treatment 5 (F:B=3.68), following a 3rd order polynomial trendline (r2=0.99) when correlated with initial treatment soil C mass; d) decreases in soil respiration, from 44% of Initial-Soil C substrate respired in bacterial-dominant low-C (0.14%) soils (F:B = 0.04) to 11% in fungal dominant (F:B = 3.68), high-C percent (5.30% C) soils (y = -0.108ln(x)+ 0.4987; r2= 0.95). Increasing the F:B in the soils of agroecosystems may provide more efficient accumulation and partitioning of photosynthate C into plant and soil biomass, improved N fixation and beneficial increases in total carbon use efficiencies. Collectively, these benefits could provide a practical and cost-effective path towards: improving crop production, reducing N-fertilizer inputs, promoting a more sustainable agricultural system, while providing a cost-effective approach for capturing and storing atmospheric carbon (CO2) in soils of agroecosystems.

scholarly journals Responses of the Soil Microbial Community to Salinity Stress in Maize Fields

Biology ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 1114
Author(s):  
Yaling Hou ◽  
Wenzhi Zeng ◽  
Menglu Hou ◽  
Zhao Wang ◽  
Ying Luo ◽  
...  
Keyword(s):  
Microbial Community ◽  
Salinity Stress ◽  
Soil Microbial Community ◽  
Bulk Soil ◽  
Available Phosphorus ◽  
Saline Soils ◽  
Community Structures ◽  
Soil Microbial Community Structure ◽  
Soil Microbial ◽  
Positive Correlations

To investigate the diversity and structure of soil bacterial and fungal communities in saline soils, soil samples with three increasing salinity levels (S1, S2 and S3) were collected from a maize field in Yanqi, Xinjiang Province, China. The results showed that the K+, Na+, Ca2+ and Mg2+ values in the bulk soil were higher than those in the rhizosphere soil, with significant differences in S2 and S3 (p < 0.05). The enzyme activities of alkaline phosphatase (ALP), invertase, urease and catalase (CAT) were lower in the bulk soil than those in the rhizosphere. Principal coordinate analysis (PCoA) demonstrated that the soil microbial community structure exhibited significant differences between different salinized soils (p < 0.001). Data implied that the fungi were more susceptible to salinity stress than the bacteria based on the Shannon and Chao1 indexes. Mantel tests identified Ca2+, available phosphorus (AP), saturated electrical conductivity (ECe) and available kalium (AK) as the dominant environmental factors correlated with bacterial community structures (p < 0.001); and AP, urease, Ca2+ and ECe as the dominant factors correlated with fungal community structures (p < 0.001). The relative abundances of Firmicutes and Bacteroidetes showed positive correlations with the salinity gradient. Our findings regarding the bacteria having positive correlations with the level of salinization might be a useful biological indicator of microorganisms in saline soils.

scholarly journals Microbial regulation of soil carbon properties under nitrogen addition and plant inputs removal

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e7343
Author(s):  
Ran Wu ◽  
Xiaoqin Cheng ◽  
Wensong Zhou ◽  
Hairong Han
Keyword(s):  
Community Structure ◽  
Microbial Community ◽  
Microbial Biomass ◽  
Soil Carbon ◽  
Microbial Community Structure ◽  
Soil Microbial Community ◽  
Soil Microbial Communities ◽  
Nitrogen Addition ◽  
Soil Microbial Community Structure ◽  
Soil Microbial

Background Soil microbial communities and their associated enzyme activities play key roles in carbon cycling in terrestrial ecosystems. Soil microbial communities are sensitive to resource availability, but the mechanisms of microbial regulation have not been thoroughly investigated. Here, we tested the mechanistic relationships between microbial responses and multiple interacting resources. Methods We examined soil carbon properties, soil microbial community structure and carbon-related functions under nitrogen addition and plant inputs removal (litter removal (NL), root trench and litter removal (NRL)) in a pure Larix principis-rupprechtii plantation in northern China. Results We found that nitrogen addition affected the soil microbial community structure, and that microbial biomass increased significantly once 100 kg ha−1 a−1 of nitrogen was added. The interactions between nitrogen addition and plant inputs removal significantly affected soil bacteria and their enzymatic activities (oxidases). The NL treatment enhanced soil microbial biomass under nitrogen addition. We also found that the biomass of gram-negative bacteria and saprotrophic fungi directly affected the soil microbial functions related to carbon turnover. The biomass of gram-negative bacteria and peroxidase activity were key factors controlling soil carbon dynamics. The interactions between nitrogen addition and plant inputs removal strengthened the correlation between the hydrolases and soil carbon. Conclusions This study showed that nitrogen addition and plant inputs removal could alter soil enzyme activities and further affect soil carbon turnover via microbial regulation. The increase in soil microbial biomass and the microbial regulation of soil carbon both need to be considered when developing effective sustainable forest management practices for northern China. Moreover, further studies are also needed to exactly understand how the complex interaction between the plant and below-ground processes affects the soil microbial community structure.

scholarly journals The influence of soil microbial community structure on carbon and nitrogen partitioning in plant/soil ecosystems

2017 ◽  
Author(s):  
David C. Johnson
Keyword(s):  
Microbial Community ◽  
Soil Respiration ◽  
Soil Microbial Community ◽  
Cost Effective ◽  
Total Carbon ◽  
N Fixation ◽  
Soil Microbial Community Structure ◽  
Soil C ◽  
Soil Microbial ◽  
Initial Soil

A greenhouse study was conducted to evaluate the influence of increasing soil fungal-to-bacterial ratios (F:B) on the allocation of plant-photosynthate carbon into the carbon (C) and nitrogen (N) partitions (g) of plant components (root, shoot and fruit), New-Soil C and N, and Soil-Respiration C (CO2). Six (6) experimental treatment soils were formulated to provide linearly increasing: initial-soil C% (0.14% – 5.3%); initial-soil N% (0.01% - 0.40%); and soil microbial community (SMC) populations progressing from bacterial dominant (F:B=0.04) to fungal dominant (F:B=3.68) while still maintaining significant SMC population homogeneity. In an 86-day greenhouse experiment, growing chile plants (Capsicum annuum) in treatment soils with increasing F:B (0.4-3.68), the following was observed: a) a continuous linear increase (3% up to 56%) in the partitioning of total plant-photosynthate C into plant biomass (root, shoot and fruit) when regressed to initial F:B (m=0.13; r2=0.96); b) approximately 93% of the flow of plant-photosynthate C was partitioned into New-Soil C in Treatment 0 (F:B = 0.04), to a minimum of 47% in Treatment 5 (F:B = 3.68) demonstrating a negative linear correlation to treatment Initial-Soil C mass (m= -0.12; r2 = 0.97); c) conditional and coordinated flow of system C resources into nitrogen (N) fixation (est. C cost for N fixation at 6:1), with 1.21 g C partitioned to N fixation in Treatment 0 (F:B=0.04), peaking at 6.92 g C in Treatment 2 (F:B=1.6), and final C partitioning to N fixation of 2.91 g C in Treatment 5 (F:B=3.68), following a 3rd order polynomial trendline (r2=0.99) when correlated with initial treatment soil C mass; d) decreases in soil respiration, from 44% of Initial-Soil C substrate respired in bacterial-dominant low-C (0.14%) soils (F:B = 0.04) to 11% in fungal dominant (F:B = 3.68), high-C percent (5.30% C) soils (y = -0.108ln(x)+ 0.4987; r2= 0.95). Increasing the F:B in the soils of agroecosystems may provide more efficient accumulation and partitioning of photosynthate C into plant and soil biomass, improved N fixation and beneficial increases in total carbon use efficiencies. Collectively, these benefits could provide a practical and cost-effective path towards: improving crop production, reducing N-fertilizer inputs, promoting a more sustainable agricultural system, while providing a cost-effective approach for capturing and storing atmospheric carbon (CO2) in soils of agroecosystems.

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