scholarly journals Microbial characteristics, carbon and nitrogen content in cambisols and luvisols

2011 ◽  
Vol 50 (No. 5) ◽  
pp. 196-204 ◽  
Author(s):  
L. Růžek ◽  
K. Voříšek ◽  
S. Strnadová ◽  
M. Nováková ◽  
W. Barabasz

Tested soils (1991&ndash;2002) were defined by chemical, textural and microbial characteristics. From the tests which describe cambisols, the following parameters have to be stressed. The higher level of C<sub>org</sub> (1.20&ndash;1.76%), which resulted in quite high microbial biomass carbon content (396&ndash;625 &micro;g/g dry soil), high control respiration (0.45&ndash;0.80 mg CO<sub>2</sub>/h/100 g dry soil) and potential nitrification with (NH<sub>4</sub>)<sub>2</sub>SO<sub>4</sub> (6.7&ndash;18.4 mg N-NO<sub>3</sub>/8 days/100 g dry soil). Studied luvisols reached typical levels: C<sub>org</sub> (0.97&ndash;1.22%), C<sub>MB</sub> (398&ndash;503 &micro;g/g dry soil), control respiration (0.46&ndash;0.57 mg CO<sub>2</sub>/h/100 g dry soil), potential nitrification with (NH<sub>4</sub>)<sub>2</sub>SO<sub>4</sub> (3.2&ndash;9.9 mg N-NO<sub>3</sub>/8 days/100 g dry soil). Lower levels of organic carbon and a medium level of microbial biomass raised in higher ratio C<sub>MB</sub>/C<sub>org </sub>(average 4.0%). Highly significant differences (p &lt; 0.01) between cambisols and luvisols were determined for C<sub>org</sub>, N<sub>t</sub>, pH(KCl), C<sub>MB</sub>, C<sub>MB</sub>/C<sub>org</sub>, C<sub>E</sub>, control respiration and potential nitrification, while the difference in potential ammonification with peptone was at level p &lt; 0.05. With the exemption of ratio C<sub>MB</sub>/C<sub>org</sub> all cambisol characteristics were higher than luvisol ones. Studied soils were evaluated by six biological criteria (C<sub>MB</sub>; ratios: C<sub>MB</sub>/C<sub>org</sub>, C<sub>E</sub>/C<sub>MB</sub>, potential/control respiration, potential/control ammonification, potential/control nitrification). These criteria distinguished tested soils into three groups. The first one includes two localities in the mountain region (Červen&aacute; Voda 809, 810; altitude 565&ndash;590 m) defined as stagnic cambisols with higher content of C<sub>org</sub> (1.40, respective 1.76%) and simultaneously with the highest biomass of micro-organisms from all tested soils (C<sub>MB</sub>,625, respective 621 &micro;g/g dry soil). It is not surprising that microbial activities (respiration, nitrification) at these localities were also high. The majority of the studied localities (one eutric cambisol and four luvisols) belongs to the medium group. The third group includes two localities (Neumětely &ndash; haplic luvisol, Čist&aacute; u Rakovn&iacute;ka &ndash; eutric cambisol) where biological criteria was mostly the worst. In the period 1993&ndash;2002 microbial biomass carbon was for both sites in the range of 357&ndash;458 &micro;g/g dry soil which are not so bad values, but in comparison with localities in mountain wet region they are low. This status was issued in the lower ratio C<sub>MB</sub>/C<sub>org</sub> (2.71&ndash;3.77%).

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Mara Regina Moitinho ◽  
Daniel De Bortoli Teixeira ◽  
Elton da Silva Bicalho ◽  
Alan Rodrigo Panosso ◽  
Antonio Sergio Ferraudo ◽  
...  

AbstractThe spatial structure of soil CO2 emission (FCO2) and soil attributes are affected by different factors in a highly complex way. In this context, this study aimed to characterize the spatial variability patterns of FCO2 and soil physical, chemical, and microbiological attributes in a sugarcane field area after reform activities. The study was conducted in an Oxisol with the measurement of FCO2, soil temperature (Ts), and soil moisture (Ms) in a regular 90 × 90-m grid with 100 sampling points. Soil samples were collected at each sampling point at a depth of 0–0.20 m to determine soil physical (density, macroporosity, and microporosity), particle size (sand, silt, and clay), and chemical attributes (soil organic matter, pH, P, K, Ca, Mg, Al, H + Al, cation exchange capacity, and base saturation). Geostatistical analyses were performed to assess the spatial variability and map soil attributes. Two regions (R1 and R2) with contrasting emission values were identified after mapping FCO2. The abundance of bacterial 16S rRNA, pmoA, and nifH genes, determined by real-time quantitative PCR (qPCR), enzymatic activity (dehydrogenase, urease, cellulase, and amylase), and microbial biomass carbon were determined in R1 and R2. The mean values of FCO2 (2.91 µmol m−2 s−1), Ts (22.6 °C), and Ms (16.9%) over the 28-day period were similar to those observed in studies also conducted under Oxisols in sugarcane areas and conventional soil tillage. The spatial pattern of FCO2 was similar to that of macropores, air-filled pore space, silt content, soil organic matter, and soil carbon decay constant. No significant difference was observed between R1 and R2 for the copy number of bacterial 16S rRNA and nifH genes, but the results of qPCR for the pmoA gene presented differences (p < 0.01) between regions. The region R1, with the highest FCO2 (2.9 to 4.2 µmol m−2 s−1), showed higher enzymatic activity of dehydrogenase (33.02 µg TPF g−1 dry soil 24 h−1), urease (41.15 µg NH4–N g−1 dry soil 3 h−1), amylase (73.84 µg glucose g−1 dry soil 24 h−1), and microbial biomass carbon (41.35 µg C g−1 soil) than R2, which had the lowest emission (1.9 to 2.7 µmol m−2 s−1). In addition, the soil C/N ratio was higher in R2 (15.43) than in R1 (12.18). The spatial pattern of FCO2 in R1 and R2 may not be directly related to the total amount of the microbial community (bacterial 16S rRNA) in the soil but to the specific function that these microorganisms play regarding soil carbon degradation (pmoA).


Forests ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 684
Author(s):  
Mengke Cai ◽  
Shiping Xing ◽  
Xiaoqing Cheng ◽  
Li Liu ◽  
Xinhao Peng ◽  
...  

The stoichiometric ratios of elements in microorganisms play an important role in biogeochemical cycling and evaluating the nutritional limits of microbial growth, but the effects of thinning treatment on the stoichiometric ratio of carbon, nitrogen, and phosphorus in microorganisms remain unclear. We conducted research in a Larix principis-rupprechtti Mayr. plantation to determine the main factors driving microbial carbon (C): nitrogen (N): phosphorus (P) stoichiometry following thinning and the underlying mechanisms of these effects. The plantation study varied in thinning intensity from 0% tree removal (control), 15% tree reduction (high density plantation, HDP), 35% tree reduction (medium density plantation, MDP), and 50% tree reduction (low density plantation, LDP). Our results indicated that medium density plantation significantly increased litter layer biomass, soil temperature, and other soil properties (e.g., soil moisture and nutrient contents). Understory vegetation diversity (i.e., shrub layer and herb layer) was highest in the medium density plantation. Meanwhile, thinning had a great influence on the biomass of microbial communities. For example, the concentration of phospholipid fatty acids (PLFA) for bacteria and fungi in the medium density plantation (MDP) was significantly higher than in other thinning treatments. Combining Pearson correlation analysis, regression modeling, and stepwise regression demonstrated that the alteration of the microbial biomass carbon: nitrogen was primarily related to gram-positive bacteria, gram-negative bacteria, soil temperature, and soil available phosphorus. Variation in bacteria, actinomycetes, gram-positive bacteria, gram–negative bacteria, and soil total phosphorus was primarily associated with shifts in microbial biomass carbon: phosphorus. Moreover, changes in microbial biomass nitrogen: phosphorus were regulated by actinomycetes, gram-negative bacteria, and soil temperature. In conclusion, our research indicates that the stoichiometric ratios of elements in microorganisms could be influenced by thinning management, and emphasizes the importance of soil factors and microbial communities in driving soil microbial stoichiometry.


Forests ◽  
2018 ◽  
Vol 9 (9) ◽  
pp. 508 ◽  
Author(s):  
Zhiwei Ge ◽  
Shuiyuan Fang ◽  
Han Chen ◽  
Rongwei Zhu ◽  
Sili Peng ◽  
...  

Soil resident water-stable macroaggregates (diameter (Ø) > 0.25 mm) play a critical role in organic carbon conservation and fertility. However, limited studies have investigated the direct effects of stand development on soil aggregation and its associated mechanisms. Here, we examined the dynamics of soil organic carbon, water-stable macroaggregates, litterfall production, fine-root (Ø < 1 mm) biomass, and soil microbial biomass carbon with stand development in poplar plantations (Populus deltoides L. ‘35’) in Eastern Coastal China, using an age sequence (i.e., five, nine, and 16 years since plantation establishment). We found that the quantity of water-stable macroaggregates and organic carbon content in topsoil (0–10 cm depth) increased significantly with stand age. With increasing stand age, annual aboveground litterfall production did not differ, while fine-root biomass sampled in June, August, and October increased. Further, microbial biomass carbon in the soil increased in June but decreased when sampled in October. Ridge regression analysis revealed that the weighted percentage of small (0.25 mm ≤ Ø < 2 mm) increased with soil microbial biomass carbon, while that of large aggregates (Ø ≥ 2 mm) increased with fine-root biomass as well as microbial biomass carbon. Our results reveal that soil microbial biomass carbon plays a critical role in the formation of both small and large aggregates, while fine roots enhance the formation of large aggregates.


1996 ◽  
Vol 76 (4) ◽  
pp. 459-467 ◽  
Author(s):  
William R. Horwath ◽  
Eldor A. Paul ◽  
David Harris ◽  
Jeannette Norton ◽  
Leslie Jagger ◽  
...  

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


2015 ◽  
Vol 12 (22) ◽  
pp. 6751-6760 ◽  
Author(s):  
Z. H. Zhou ◽  
C. K. Wang

Abstract. Microbial metabolism plays a key role in regulating the biogeochemical cycle of forest ecosystems, but the mechanisms driving microbial growth are not well understood. Here, we synthesized 689 measurements on soil microbial biomass carbon (Cmic) and nitrogen (Nmic) and related parameters from 207 independent studies published up to November 2014 across China's forest ecosystems. Our objectives were to (1) examine patterns in Cmic, Nmic, and microbial quotient (i.e., Cmic / Csoil and Nmic / Nsoil rates) by climate zones and management regimes for these forests; and (2) identify the factors driving the variability in the Cmic, Nmic, and microbial quotient. There was a large variability in Cmic (390.2 mg kg−1), Nmic (60.1 mg kg−1, Cmic : Nmic ratio (8.25), Cmic / Csoil rate (1.92 %), and Nmic / Nsoil rate (3.43 %) across China's forests. The natural forests had significantly greater Cmic (514.1 mg kg−1 vs. 281.8 mg kg−1) and Nmic (82.6 mg kg−1 vs. 39.0 mg kg−1) than the planted forests, but had less Cmic : Nmic ratio (7.3 vs. 9.2) and Cmic / Csoil rate (1.7 % vs. 2.1 %). Soil resources and climate together explained 24.4–40.7 % of these variations. The Cmic : Nmic ratio declined slightly with Csoil : Nsoil ratio, and changed with latitude, mean annual temperature and precipitation, suggesting a plasticity of microbial carbon-nitrogen stoichiometry. The Cmic / Csoil rate decreased with Csoil : Nsoil ratio, whereas the Nmic / Nsoil rate increased with Csoil : Nsoil ratio; the former was influenced more by soil resources than by climate, whereas the latter was influenced more by climate. These results suggest that soil microbial assimilation of carbon and nitrogen are jointly driven by soil resources and climate, but may be regulated by different mechanisms.


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