Divergent vertical distributions of microbial biomass with soil depth among groups and land uses

2021 ◽  
Vol 292 ◽  
pp. 112755
Author(s):  
Tingting Sun ◽  
Yugang Wang ◽  
Manuel Esteban Lucas-Borja ◽  
Xin Jing ◽  
Wenting Feng
Keyword(s):  
Microbial Biomass ◽  
Soil Depth ◽  
Land Uses ◽  
Vertical Distributions

A multi-decade assessment of the impact of large fire events on sediment redistribution using LAPSUS - the Águeda catchment, north-central Portugal

2021 ◽  
Author(s):  
Dante Föllmi ◽  
Jantiene Baartman ◽  
João Pedro Nunes ◽  
Akli Benali
Keyword(s):  
Soil Depth ◽  
Spatial Scales ◽  
Fire Severity ◽  
Sediment Dynamics ◽  
Land Uses ◽  
Erosion Rates ◽  
Erosion Processes ◽  
Sediment Redistribution ◽  
Central Portugal ◽  
The Impact

<p><strong>Abstract</strong></p><p>Wildfires have become an increasing threat for Mediterranean ecosystems, due to increasing climate change induced wildfire activity and changing land management practices. Apart from the initial risk, fire can alter the soil in various ways depending on different fire severities and thus post-fire erosion processes are an important component in assessing wildfires’ negative effects. Recent post-fire erosion (modelling) studies often focus on a short time window and lack the attention for sediment dynamics at larger spatial scales. Yet, these large spatial and temporal scales are fundamental for a better understanding of catchment sediment dynamics and long-term destructive effects of multiple fires on post-fire erosion processes. In this study the landscape evolution model LAPSUS was used to simulate erosion and deposition in the 404 km<sup>2</sup> Águeda catchment in northern-central Portugal over a 41 year (1979-2020) timespan. To include variation in fire severity and its impact on the soil four burnt severity classes, represented by the difference Normalized Burn Ratio (dNBR), were parameterized. Although model calibration was difficult due to lack of spatial and temporal measured data, the results show that average post-fire net erosion rates were significantly higher in the wildfire scenarios (5.95 ton ha<sup>-1</sup> yr<sup>-1</sup>) compared to those of a non-wildfire scenario (0.58 ton ha<sup>-1</sup> yr<sup>-1</sup>). Furthermore, erosion values increased with a higher level of burnt severity and multiple fires increased the overall sediment build-up in the catchment, fostering an increase in background sediment yield. Simulated erosion patterns showed great spatial variability with large deposition and erosion rates inside streams. Due to this variability, it was difficult to identify land uses that were most sensitive for post-fire erosion, because some land-uses were located in more erosion-sensitive areas (e.g. streams, gullies) or were more affected by high burnt severity levels than others. Despite these limitations, LAPSUS performed well on addressing spatial sediment processes and has the ability to contribute to pre-fire management strategies. For instance, the percentage soil loss map (i.e. comparison of erosion and soil depth maps) could identify locations at risk.</p>

scholarly journals Perennial herbaceous legumes as live soil mulches and their effects on C, N and P of the microbial biomass

2003 ◽  
Vol 60 (1) ◽  
pp. 139-147 ◽  
Author(s):  
Gustavo Pereira Duda ◽  
José Guilherme Marinho Guerra ◽  
Marcela Teixeira Monteiro ◽  
Helvécio De-Polli ◽  
Marcelo Grandi Teixeira
Keyword(s):  
Microbial Biomass ◽  
Soil Depth ◽  
Vegetation Management ◽  
Pueraria Phaseoloides ◽  
Organic C ◽  
Arachis Pintoi ◽  
Factorial Combination ◽  
C And N ◽  
Microbial C ◽  
Macroptilium Atropurpureum

The use of living mulch with legumes is increasing but the impact of this management technique on the soil microbial pool is not well known. In this work, the effect of different live mulches was evaluated in relation to the C, N and P pools of the microbial biomass, in a Typic Alfisol of Seropédica, RJ, Brazil. The field experiment was divided in two parts: the first, consisted of treatments set in a 2 x 2 x 4 factorial combination of the following factors: live mulch species (Arachis pintoi and Macroptilium atropurpureum), vegetation management after cutting (leaving residue as a mulch or residue remotion from the plots) and four soil depths. The second part had treatments set in a 4 x 2 x 2 factorial combination of the following factors: absence of live mulch, A. pintoi, Pueraria phaseoloides, and M. atropurpureum, P levels (0 and 88 kg ha-1) and vegetation management after cutting. Variation of microbial C was not observed in relation to soil depth. However, the amount of microbial P and N, water soluble C, available C, and mineralizable C decreased with soil depth. Among the tested legumes, Arachis pintoi promoted an increase of microbial C and available C content of the soil, when compared to the other legume species (Pueraria phaseoloides and Macroptilium atropurpureum). Keeping the shoot as a mulch promoted an increase on soil content of microbial C and N, total organic C and N, and organic C fractions, indicating the importance of this practice to improve soil fertility.

scholarly journals Defining a realistic control for the chloroform fumigation-incubation method using microscopic counting and 14C-substrates

1996 ◽  
Vol 76 (4) ◽  
pp. 459-467 ◽  
Author(s):  
William R. Horwath ◽  
Eldor A. Paul ◽  
David Harris ◽  
Jeannette Norton ◽  
Leslie Jagger ◽  
...  
Keyword(s):  
Microbial Biomass ◽  
Soil Microbial Biomass ◽  
Microbial Biomass Carbon ◽  
Soil Depth ◽  
Temporal Trends ◽  
Biomass Carbon ◽  
Soil Microbial ◽  
Microbial C ◽  
Parameter Values ◽  
Chloroform Fumigation

Chloroform fumigation-incubation (CFI) has made possible the extensive characterization of soil microbial biomass carbon (C) (MBC). Defining the non-microbial C mineralized in soils following fumigation remains the major limitation of CFI. The mineralization of non-microbial C during CFI was examined by adding 14C-maize to soil before incubation. The decomposition of the 14C-maize during a 10-d incubation after fumigation was 22.5% that in non-fumigated control soils. Re-inoculation of the fumigated soil raised 14C-maize decomposition to 77% that of the unfumigated control. A method was developed which varies the proportion of mineralized C from the unfumigated soil (UFC) that is subtracted in calculating CFI biomasss C. The proportion subtracted (P) varies according to a linear function of the ratio of C mineralized in the fumigated (FC) and unfumigated samples (FC/UFC) with two parameters K1 and K2 (P = K1FC/UFC) + K2). These parameters were estimated by regression of CFI biomass C, calculated according to the equation MBC = (FC − PUFC)/0.41, against that derived by direct microscopy in a series of California soils. Parameter values which gave the best estimate of microscopic biomass from the fumigation data were K1 = 0.29 and K2 = 0.23 (R2 = 0.87). Substituting these parameter values, the equation can be simplified to MBC = 1.73FC − 0.56UFC. The equation was applied to other CFI data to determine its effect on the measurement of MBC. The use of this approach corrected data that were previously difficult to interpret and helped to reveal temporal trends and changes in MBC associated with soil depth. Key words: Chloroform fumigation-incubation, soil microbial biomass, microscopically estimated biomass, carbon, control, 14C

scholarly journals Microbial Utilisation of Aboveground Litter-Derived Organic Carbon Within a Sandy Dystric Cambisol Profile

2021 ◽  
Vol 1 ◽  
Author(s):  
Sebastian Preusser ◽  
Patrick Liebmann ◽  
Andres Stucke ◽  
Johannes Wirsching ◽  
Karolin Müller ◽  
...  
Keyword(s):  
Microbial Biomass ◽  
Organic Carbon ◽  
Soil Depth ◽  
Sampling Period ◽  
Beech Forest ◽  
Stable Isotope Labelling ◽  
C Stocks ◽  
Microbial Groups ◽  
Aboveground Litter ◽  
Over Time

Litter-derived dissolved organic carbon (DOC) is considered to be a major source of stabilised C in soil. Here we investigated the microbial utilisation of litter-derived DOC within an entire soil profile using a stable isotope labelling experiment in a temperate beech forest. The natural litter layer of a Dystric Cambisol was replaced by 13C enriched litter within three areas of each 6.57 m−2 for 22 months and then replaced again by natural litter (switching-off the 13C input). Samples were taken continuously from 0 to 180 cm depths directly after the replacement of the labelled litter, and 6 and 18 months thereafter. We followed the pulse of 13C derived from aboveground litter into soil microorganisms through depth and over time by analysing 13C incorporation into microbial biomass and phospholipid fatty acids. Throughout the sampling period, most of the litter-derived microbial C was found in the top cm of the profile and only minor quantities were translocated to deeper soil. The microbial 13C stocks below 30 cm soil depth at the different samplings accounted constantly for only 6–12% of the respective microbial 13C stocks of the entire profile. The peak in proportional enrichment of 13C in subsoil microorganisms moved from upper (≤ 80 cm soil depth) to lower subsoil (80–160 cm soil depth) within a period of 6 months after switch-off, and nearly disappeared in microbial biomass after 18 months (< 1%), indicating little long-term utilisation of litter-derived C by subsoil microorganisms. Among the different microbial groups, a higher maximum proportion of litter-derived C was found in fungi (up to 6%) than in bacteria (2%), indicating greater fungal than bacterial dependency on litter-derived C in subsoil. However, in contrast to topsoil, fungi in subsoil had only a temporarily restricted increase in litter C incorporation, while in the Gram-positive bacteria, the C incorporation in subsoil raised moderately over time increasingly contributing to the group-specific C stock of the entire profile (up to 9%). Overall, this study demonstrated that microorganisms in topsoil of a Dystric Cambisol process most of the recently deposited aboveground litter C, while microbial litter-derived C assimilation in subsoil is low.

scholarly journals Soil Microbial Biomass and Community Composition Relates to Poplar Genotypes and Environmental Conditions

Forests ◽  
2020 ◽  
Vol 11 (3) ◽  
pp. 262 ◽  
Author(s):  
Leszek Karliński ◽  
Sabine Ravnskov ◽  
Maria Rudawska
Keyword(s):  
Microbial Biomass ◽  
Microbial Communities ◽  
Community Composition ◽  
Soil Depth ◽  
Abiotic Factors ◽  
Soil Conditions ◽  
Main Role ◽  
Site Factors ◽  
Host Genotype ◽  
The Impact

Poplars, known for their diversity, are trees that can develop symbiotic relationships with several groups of microorganisms. The genetic diversity of poplars and different abiotic factors influence the properties of the soil and may shape microbial communities. Our study aimed to analyse the impact of poplar genotype on the biomass and community composition of the microbiome of four poplar genotypes grown under different soil conditions and soil depths. Of the three study sites, established in the mid-1990s, one was near a copper smelter, whereas the two others were situated in unpolluted regions, but were differentiated according to the physicochemical traits of the soil. The whole-cell fatty acid analysis was used to determine the biomass and proportions of gram-positive, gram-negative and actinobacteria, arbuscular fungi (AMF), other soil fungi, and protozoa in the whole microbial community in the soil. The results showed that the biomass of microorganisms and their contributions to the community of organisms in the soil close to poplar roots were determined by both factors: the tree-host genotype and the soil environment. However, each group of microorganisms was influenced by these factors to a different degree. In general, the site effect played the main role in shaping the microbial biomass (excluding actinobacteria), whereas tree genotype determined the proportions of the fungal and bacterial groups in the microbial communities and the proportion of AMF in the fungal community. Bacterial biomass was influenced more by site factors, whereas fungal biomass more by tree genotype. With increasing soil depth, a decrease in the biomass of all microorganisms was observed; however, the proportions of the different microorganisms within the soil profile were the result of interactions between the host genotype and soil conditions. Despite the predominant impact of soil conditions, our results showed the important role of poplar genotype in shaping microorganism communities in the soil.

scholarly journals Land–Use Changes Influencing C Sequestration and Quality in Topsoil and Subsoil

Agronomy ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 520 ◽  
Author(s):  
Benjapon Kunlanit ◽  
Somchai Butnan ◽  
Patma Vityakon
Keyword(s):  
Land Use ◽  
Humic Acid ◽  
Humic Acids ◽  
Soil Depth ◽  
Land Use Changes ◽  
Rice Paddy ◽  
C Sequestration ◽  
Land Uses ◽  
Intergovernmental Panel ◽  
Soc Stocks

Soil capacity as a major carbon (C) sink is influenced by land use. Estimates of soil organic carbon (SOC) sequestration have mostly focused on topsoils [0–30 cm official Intergovernmental Panel on Climate Change (IPCC) soil depth]. We investigated SOC stocks and their quality as influenced by land-use changes. Soil samples were collected from five soil depths down to 100 cm of three adjacent fields each representing a different land use—forest, cassava, and rice paddy—in Northeast Thailand. Sequestration of SOC in topsoils under all land uses was higher, as indicated by SOC stocks (59.0–82.0 Mg ha−1) than subsoils (30–100 cm) (27.0–33.0 Mg ha−1). The soil profile (0–100 cm) of the forest had higher stocks of SOC and humic acid (115.0 and 6.8 Mg ha−1, respectively) than those of cultivated land uses [paddy (100.0 and 4.8 Mg ha−1, respectively) and cassava (87.0 and 2.3 Mg ha−1, respectively)], which accounted for an average 30% increase in SOC sequestration over those with only topsoil. Topsoils of the forest had higher humic acid content but narrower E4:E6 ratio [the ratio of absorbances at 465 nm (E4) and at 665 nm (E6)] of humic acids (2.8), indicating a higher degree of humification and stabilization than the cultivated soils (3.2–3.6). Subsoil C was higher quality, as indicated by the lower E4:E6 ratio of humic acids than topsoils in all land uses.

scholarly journals Vertical distributions of soil microbial biomass carbon: a global dataset

Data in Brief ◽  
2020 ◽  
Vol 32 ◽  
pp. 106147
Author(s):  
Tingting Sun ◽  
Yugang Wang ◽  
Dafeng Hui ◽  
Xin Jing ◽  
Wenting Feng
Keyword(s):  
Microbial Biomass ◽  
Soil Microbial Biomass ◽  
Microbial Biomass Carbon ◽  
Biomass Carbon ◽  
Soil Microbial ◽  
Soil Microbial Biomass Carbon ◽  
Vertical Distributions

scholarly journals Land Use Changes Affecting Soil Organic Matter Accumulation in Topsoil and Subsoil in Northeast Thailand

2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Benjapon Kunlanit ◽  
Laksanara Khwanchum ◽  
Patma Vityakon
Keyword(s):  
Land Use ◽  
Organic Matter ◽  
Soil Organic Matter ◽  
Agricultural Land ◽  
Soil Depth ◽  
General Pattern ◽  
Clay Fraction ◽  
High Rate ◽  
Soil Profiles ◽  
Land Uses

The objectives of this study were to investigate effects of land use on accumulation of soil organic matter (SOM) in the soil profile (0–100 cm) and to determine pattern of SOM stock distribution in soil profiles. Soil samples were collected from five soil depths at 20 cm intervals from 0 to 100 cm under four adjacent land uses including forest, cassava, sugarcane, and paddy lands located in six districts of Maha Sarakham province in the Northeast of Thailand. When considering SOM stock among different land uses in all locations, forest soils had significantly higher total SOM stocks in 0–100 cm (193 Mg·C·ha−1) than those in cassava, sugarcane, and paddy soils in all locations. Leaf litter and remaining rice stover on soil surfaces resulted in a higher amount of SOM stocks in topsoil (0–20 cm) than subsoil (20–100 cm) in some forest and paddy land uses. General pattern of SOM stock distribution in soil profiles was such that the SOM stock declined with soil depth. Although SOM stocks decreased with depth, the subsoil stock contributes to longer term storage of C than topsoils as they are more stabilized through adsorption onto clay fraction in finer textured subsoil than those of the topsoils. Agricultural practices, notably applications of organic materials, such as cattle manure, could increase subsoil SOM stock as found in some agricultural land uses (cassava and sugarcane) in some location in our study. Upland agricultural land uses, notably cassava, caused high rate of soil degradation. To restore soil fertility of these agricultural lands, appropriate agronomic practices including application of organic soil amendments, return of crop residues, and reduction of soil disturbance to increase and maintain SOM stock, should be practiced.

scholarly journals Comparative Study on Soil Microbial Biomass in Tarai and Hill Sal (Shorearobusta Gaertn.) Forests of Tropical Region in Eastern Nepal

2020 ◽  
Vol 19 (1) ◽  
pp. 16-25
Author(s):  
Krishna Prasad Bhattarai ◽  
Tej Narayan Mandal
Keyword(s):  
Microbial Biomass ◽  
Comparative Study ◽  
Rainy Season ◽  
Turnover Rate ◽  
Soil Microbial Biomass ◽  
Soil Depth ◽  
Soil Samples ◽  
Tropical Region ◽  
Soil Microbial ◽  
Sal Forest

A comparative study was conducted to investigate the effect of altitudinal variation and seasonality on soil microbial biomass carbon (MB-C), nitrogen (MB-N), and phosphorus (MB-P) between Tarai Sal forest (TSF) and Hill Sal forest (HSF) of the tropical region in eastern Nepal. Soil microbial biomass was estimated by chloroform fumigation - extraction method in summer, rainy and winter seasons in the upper (0-15 cm) soil depth in both forests. Pre-conditioned soil samples were saturated with purified liquid chloroform, represented fumigated sample. Another set of soil samples without using chloroform, represented unfumigated samples and soil biomass was estimated from these samples. MB-C, MB-N, and MB-P were higher by 66%, 31%, and 9%, respectively, in HSF than TSF. Distinct seasonality was observed in soil microbial biomass. It was maximum in summer and minimum in rainy season in both the forest stands. The value decreased from summer to rainy season by 46 to 67% in HSF and by 32 to 80% in TSF. Higher soil microbial biomass in the summer season may be due to its accumulation in soil when the plant growth and nutrient demand are minimal. Analysis of variance suggested that MB-C, MB-N, and MB-P were significantly different for both sites and seasons (P < 0.001). Soil organic carbon, TN, and TP were positively correlated with MB-C, MB-N, and MB-P in both the forests. In conclusion, the higher value of soil microbial biomass in HSF may be due to the higher concentration of soil organic matter and decreasing turnover rate of microbial biomass due to higher altitude. On the other hand, the lower value of microbial biomass at TSF may indicate its fast turnover rate due to lowland tropics to enhance the nutrient cycling process.

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