Journal articles on the topic 'Microbial biomass carbon (MBC)'
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1
Horwath, William R., Eldor A. Paul, David Harris, Jeannette Norton, Leslie Jagger, and Kenneth A. Horton. "Defining a realistic control for the chloroform fumigation-incubation method using microscopic counting and 14C-substrates." Canadian Journal of Soil Science 76, no. 4 (November 1, 1996): 459–67. http://dx.doi.org/10.4141/cjss96-057.
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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
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Zhang, Cheng Hu, Ting Ting Song, Ju Liu, Hui Juan Xia, and Jian Zhu Wang. "Microbial Activity in Soils of Vegetation-Growing Concrete Slopes." Advanced Materials Research 599 (November 2012): 124–27. http://dx.doi.org/10.4028/www.scientific.net/amr.599.124.
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Natural restoration slope and vegetation-growing concrete slope were selected as plots. Soil water content (SWC), pH, and soil organic matter, total nitrogen content (TN), total organic carbon (TOC), microbial biomass carbon (MBC), microbial biomass nitrogen (MBN), basal respiration, microbial quotient and metabolic quotient (qCO2) were analyzed. The main results show that: Soil organic matter, TN and MBC of 0-10 cm soil in the natural restoration slope are significantly lower than that in the vegetation-growing concrete slopes at 0.05 level. Both MBC and MBN show a highly significant positive correlation with soil organic matter and TN. Microbial quotient shows a highly significant negative correlation with TOC and MBN, and shows a significant negative correlation with MBC. The qCO2 shows a highly significant negative correlation with pH, and a significant negative correlation with MBC. The vegetation-growing concrete technology can improve the soil ecosystem in the impaired slope.
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Wang, Yong, Xiongsheng Liu, Fengfan Chen, Ronglin Huang, Xiaojun Deng, and Yi Jiang. "Seasonal dynamics of soil microbial biomass C and N of Keteleeria fortunei var. cyclolepis forests with different ages." Journal of Forestry Research 31, no. 6 (October 23, 2019): 2377–84. http://dx.doi.org/10.1007/s11676-019-01058-w.
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Abstract Soil microbial biomass is an important indicator to measure the dynamic changes of soil carbon pool. It is of great significance to understand the dynamics of soil microbial biomass in plantation for rational management and cultivation of plantation. In order to explore the temporal dynamics and influencing factors of soil microbial biomass of Keteleeria fortunei var. cyclolepis at different stand ages, the plantation of different ages (young forest, 5 years; middle-aged forest, 22 years; mature forest, 40 years) at the Guangxi Daguishan forest station of China were studied to examine the seasonal variation of their microbial biomass carbon (MBC) and microbial biomass nitrogen (MBN) by chloroform fumigation extraction method. It was found that among the forests of different age, MBC and MBN differed significantly in the 0–10 cm soil layer, and MBN differed significantly in the 10–20 cm soil layer, but there was no significant difference in MBC for the 10–20 cm soil layer or in either MBC or MBN for the 20–40 cm soil layer. With increasing maturity of the forest, MBC gradually decreased in the 0–10 cm soil layer and increased firstly and then decreased in the 10–20 cm and 20–40 cm soil layers, and MBN increased firstly and then decreased in all three soil layers. As the soil depth increased, both MBC and MBN gradually decreased for all three forests. The MBC and MBN basically had the same seasonal variation in all three soil layers of all three forests, i.e., high in the summer and low in the winter. Correlation analysis showed that MBC was significantly positively correlated with soil organic matter, total nitrogen, and soil moisture, whereas MBN was significantly positively correlated with soil total nitrogen. It showed that soil moisture content was the main factor determining the variation of soil microbial biomass by Redundancy analysis. The results showed that the soil properties changed continuously as the young forest grew into the middle-aged forest, which increased soil microbial biomass and enriched the soil nutrients. However, the soil microbial biomass declined as the middle-age forest continued to grow, and the soil nutrients were reduced in the mature forest.
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Mendoza, Benito, Jaime Béjar, Daniel Luna, Miguel Osorio, Mauro Jimenez, and Jesus R. Melendez. "Differences in the ratio of soil microbial biomass carbon (MBC) and soil organic carbon (SOC) at various altitudes of Hyperalic Alisol in the Amazon region of Ecuador." F1000Research 9 (May 26, 2020): 443. http://dx.doi.org/10.12688/f1000research.22922.1.
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Protecting soil fertility represents a fundamental effort of sustainable development. In this study we investigate how different altitudes affect soil microbial biomass carbon (MBC) and soil organic carbon (SOC), and their ratio, MBC/SOC in Hyperalic Alisol. MBC and SOC are well established and widely accepted microbial quotients in soil science. Our work hypothesis was that a decrease in MBC and SOC should be observed at higher altitudes. This initial assumption has been verified by our measurements, being attributed to the increase in MBC and SOC at low altitudes. Our approach should contribute to the better understanding of MBC and SOC distribution in soil and changes in MBC/SOC at various altitudes in the region.
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Wang, J. J., X. Y. Li, A. N. Zhu, X. K. Zhang, H. W. Zhang, and W. J. Liang. " Effects of tillage and residue management on soil microbial communities in North China." Plant, Soil and Environment 58, No. 1 (January 16, 2012): 28–33. http://dx.doi.org/10.17221/416/2011-pse.
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The impacts of tillage system (conventional tillage and no-tillage) and residue management (0, 50, and 100%) on soil properties and soil microbial community structure were determined in the Fengqiu State Key Agro-Ecological Experimental Station, North China. The microbial community structure was investigated by phospholipid fatty acid (PLFA) profiles. The results showed that tillage had significant effects on soil properties and soil microbial communities. In no-tillage (NT), microbial biomass carbon (MBC), total N, microbial biomass carbon/soil organic carbon (MBC/SOC), total microbes, and arbuscular mycorrhiza fungi increased, while actinomycetes, G<sup>+</sup>/G<sup>–</sup> bacteria ratio and monounsaturated fatty acids/saturated fatty acids (MUFA/STFA) decreased, compared with those in conventional tillage (CT). Residue had a significant positive effect on C/N ratio and MUFA/STFA. Canonical correspondence analysis indicated that tillage explained 76.1%, and residue management explained 0.6% of the variations in soil microbial communities, respectively. Soil microbial communities were significantly correlated with MBC, total N, C/N ratio and MBC/SOC. Among the six treatments, NT with 100% residue application obviously improved soil microbiological properties, and could be a proper management practice in the Huang-Huai-Hai Plain of China.
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Filep, T., and T. Szili-Kovács. "Effect of liming on microbial biomass carbon of acidic arenosols in pot experiments." Plant, Soil and Environment 56, No. 6 (June 3, 2010): 268–73. http://dx.doi.org/10.17221/174/2009-pse.
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In the paper we investigate the effect of liming on the microbial biomass carbon (MBC) in pot experiments during two vegetation periods. There was also another goal to get better understanding of the role of dissolved organic matter (DOM) and its quality on microbial processes. Pot experiments were carried out on two acidic soils. Liming material treatment was 0, 1, 2, 3 g CaCO<sub>3</sub> /kg soil (corresponding with 0, 1.4, 2.8, 4.1 t CaCO<sub>3</sub> /ha, respectively). On both soils, 3-3 soil samples were taken for two growing periods and the substrate-induced respiration (SIR), dissolved organic carbon and nitrogen (DOC and DON), and soil pH were determined from the soil samples. The SIR can be used to characterize the active biomass within the total microbial biomass. Liming was found to increase soil respiration and consequently MBC in the first year of the experiment, but at the maximum lime rate these values stagnated or declined in many cases on each soil. In the second year, the effects of treatments were much lower both on Kisvárda and on Nyírlugos soils. Under the given experimental conditions, when the DOC/DON ratio rose to above 30–40, disturbances appeared in N supplies to microorganisms. The N content of the easily mineralisable organic matter in the soil became so low that it inhibited the reproduction of the microorganisms.
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Jiang, Xinyu, Lixiang Cao, and Renduo Zhang. "Effects of addition of nitrogen on soil fungal and bacterial biomass and carbon utilisation efficiency in a city lawn soil." Soil Research 52, no. 1 (2014): 97. http://dx.doi.org/10.1071/sr13210.
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The aim of this study was to investigate the effects of nitrogen (N) addition on soil microbial (fungal and bacterial) biomass and carbon utilisation efficiency (CUE) in a city lawn soil. A field experiment was conducted with three N treatments (kg N ha–1 year–1): the control (0), low-N (100), and high-N (200). Soil biogeochemical properties including pH, C : N, CUE, microbial biomass C (MBC), fungal and bacterial biomass, microbial C uptake rates, and soil respiration (SR) rates were determined during a 500-day experiment. The low- and high-N treatments significantly decreased soil pH, MBC, and CUE. Available N and soil acidification caused a decline in soil MBC. Soil acidification was not beneficial for microbial biomass growth, especially for bacteria. The treatments with N changed soil biomass from bacterial-dominant to fungal-dominant. The results also showed that the CUE of bacterial-dominant soil was higher than that of fungal-dominant soil, which is contrary to previous studies. However, SR did not increase with decreased CUE under N treatments, because the addition of N limited soil microbial C uptake rates and significantly decreased soil microbial biomass. The CUE showed a negative correlation with soil temperature for the control treatment but not for the N treatments, which suggested that added N played a more important role in CUE than did soil temperature. Our results showed that addition of further N significantly alters soil biogeochemical properties, alters the ratio of bacteria to fungi, and decreases microbial carbon utilisation, which should provide important information for model-based prediction of soil C-cycling.
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Wu, Zhen Ru, Guo Mei Jia, Li Na Cao, and Fang Qing Chen. "Dynamics of Soil Microbial Properties of Substrate in Vegetation Restoration of Rock Slope." Advanced Materials Research 347-353 (October 2011): 237–40. http://dx.doi.org/10.4028/www.scientific.net/amr.347-353.237.
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Soil microbial properties have been proved to be powerful indicators of soil quality. This study analyzed the changes in soil moisture content, soil bulk density and porosity, soil organic carbon, total nitrogen, and microbial biomass of Substrate in vegetation restoration of Rock Slope. The results showed that soil moisture, soil porosity, organic carbon (OC), total nitrogen (TN) and microbial biomass carbon (MBC), microbial biomass nitrogen (MBN) and C/N increased significantly, and soil bulk density decreased gradually compared with bare rock Slope. Therefore, the results suggested that the vegetation restoration of Rock Slope could improve soil quality.
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Prasad, Mukesh, H. B. Vasistha, and P. B. Kothiyal. "Assessment of Health of Reclaimed Limestone Mine Spoil using Microbial Biomass Carbon as Biological Indicator." Indian Journal of Forestry 38, no. 3 (September 1, 2015): 223–26. http://dx.doi.org/10.54207/bsmps1000-2015-0wkd4a.
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The mining and quarrying in hill ranges of Mussoorie and Dehradun was the glaring example of deforestation and damages of forest resources at 70s and 80s. Mussoorie, the queen of hill station and Doon valley had been stripped off its green cover during this period. This reckless and unscientific exploitation of limestone deposits occurred without any thought for consequential environmental effects. The ecological restoration of these mined areas started almost more than two decades (around 80s) earlier by different agencies through applying mechanical, physical and biological measures. The microbial biomass consists mostly of bacteria and fungi which decompose plant, animal residues and soil organic matter to release carbon dioxide and plant available nutrients such as nitrogen (N), into the soil that are available for plant uptake. It is also an early indicator of changes in total Soil Organic Carbon (SOC). Unlike Total Organic Carbon (TOC), Microbial Biomass Carbon (MBC) responds quickly to soil changes. About half of the microbial biomass is located in the surface 10 cm of a soil profile. It is commonly affected by factors such as water, carbon content of soil, soil types, climate and management practices. The study was under taken to assess the role of rehabilitation/restoration of limestone mined area of Mussoorie hill on improving the health of soil using Microbial Biomass Carbon (MBC) as biological indicator. The study demonstrated the soil health status of reclaimed lime stone mine site which was dominated by Cupressus torulosa. Besides that Microbial Biomass Carbon (MBC) was also estimated under the natural forest of Quercus leucotrichophora as a control. It was estimated by Chloroform Fumigation method. It has been observed that the MBC of soil under reclaimed mined soil dominated by Cupressus torulosa ranges from 200 µg/gm to 600 µg/gm and in natural forest of Quercus leucotrichophora (Banj Oak) it ranges from 600 – 800 µg/gm which is higher than the reclaimed site. Though the MBC in reclaimed site is lower than the natural forest, however it indicating the improvement of soil quality of reclaimed mined spoil due to rehabilitation efforts carried out in these mined areas. The substratum of soil and nutrient limitation for microbial communities can affect the central role in the soil nutrient cycling which facilitate the microbial biomass. It can be concluded that reclaimed limestone mine site improving with time and it may take some more time to improve the spoil to reach the nutrient level up to natural forest.
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Banu, Nargis A., Balwant Singh, and Les Copeland. "Microbial biomass and microbial biodiversity in some soils from New South Wales, Australia." Soil Research 42, no. 7 (2004): 777. http://dx.doi.org/10.1071/sr03132.
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Eight surface soils (0–15 cm) including 1 Ferrosol, 2 Tenosols, 2 Kurosols, 1 Sodosol, 1 Chromosol, and 1 Kandosol were collected from mainly pasture sites in New South Wales. The soils had different physico-chemical properties and there were some differences between the sites in climatic conditions. Soil microbial biomass carbon (MBC) was estimated by the chloroform-fumigation extraction method, and substrate utilisation patterns determined by the Biolog method were used to assess the amount, functional diversity, substrate richness and evenness, and community structure of the microorganisms in these soils. The amount of MBC (585 µg C/g) and the microbial diversity (H´ = 3.24) were high in soils that had high clay (33%), organic C (5.96%), total N (0.45%), free iron (7.06%), moisture content (50%), and cation exchange capacitiy (133.5 mmolc/kg). These soil properties, e.g. soil moisture (r2 = 0.72), organic C (r2 = 0.58), total N (r2 = 0.63), free iron (r2 = 0.44), and EC (r2 = 0.53), were positively correlated with MBC and microbial diversity index, whereas pH and sand and silt content showed negative correlations. The climatic factors (temperature and rainfall) had no significant influence on either MBC or diversity.
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IJ, Oijagbe, Abubakar BY, Edogbanya PRO, Suleiman MO, and Olorunmola JB. "Effects of heavy metals on soil microbial biomass carbon." MOJ Biology and Medicine 4, no. 1 (2019): 30–32. http://dx.doi.org/10.15406/mojbm.2019.04.00109.
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This study was aimed at evaluating the effect of heavy metals on soil microbial processes. The effects of Lead (Pb) and Cadmium (Cd) at different concentrations were investigated over a period of eight weeks. Chloride salts of Pb and Cd were added singly and in combination to soil samples at room temperature (270C) in different polythene bags. Samples were taken from the bags at two weeks interval and measurements were taken of the microbial biomass carbon (MBC). The results showed that there was a significant decrease in the microbial biomass carbon for all treated soils from the second week to the sixth week. But there was an observed increase in microbial biomass carbon on the eight week. At the sixth week, 2000mgkg-1Pb and 40mgkg-1Cd gave the most significant decrease (P < 0.05) in microbial biomass carbon of 98%.
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Naushi, Anis, and Ajay Kumar Arya. "The effects of Heavy Metals on Microbial Biomass of Forest Soil from Tropical Deciduous Forest of Central Ganga Plain." Research Journal of Chemistry and Environment 25, no. 11 (October 25, 2021): 34–37. http://dx.doi.org/10.25303/2511rjce3437.
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This investigation was aimed toward assessing the impact of heavy metals on soil microbial cycles. The impacts of lead (Pb) and cadmium (Cd) at various concentrations were researched over a time of about two months. Chloride salts of Pb and Cd were added independently and in blend to soil samples at room temperature (27ºC) in various polythene packs. Samples were taken from the sacks at about fourteen days span and estimations were taken of the microbial biomass carbon (MBC). The outcomes showed that there was a significant reduction in the microbial biomass carbon for all treated soils from the second week to the 6th week. However, on 8th week, increase in microbial biomass carbon was observed. At the 6th week, 2000mgkg-1Pb and 40mgkg-1Cd gave the main reduction (P < 0.05) in microbial biomass carbon of 98%. A critical decrease in biomass carbon in metal contaminated soil demonstrated that this parameter is a decent marker of toxicity of metals on soil microflora.
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Wu, Zhou, Wen, Zhu, You, Qin, Li, et al. "Coniferous-Broadleaf Mixture Increases Soil Microbial Biomass and Functions Accompanied by Improved Stand Biomass and Litter Production in Subtropical China." Forests 10, no. 10 (October 6, 2019): 879. http://dx.doi.org/10.3390/f10100879.
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Although the advantages of multi-species plantations over single-species plantations have been widely recognized, the mechanisms driving these advantages remain unclear. In this study, we compared stand biomass, litter production and quality, soil properties, soil microbial community, and functions in a Pinus massoniana Lamb. and Castanopsis hystrix Miq. mixed plantation and their corresponding mono-specific plantations after 34 years afforestation in subtropical China. The results have shown that a coniferous-broadleaf mixture created significantly positive effects on stand biomass, litter production, soil microbial biomass, and activities. Firstly, the tree, shrub and herb biomass, and litter production were significantly higher in the coniferous-broadleaf mixed plantation. Secondly, although the concentrations of soil organic carbon (SOC) and total nitrogen (TN) were lower in the mixed stand, the concentrations of soil microbial biomass carbon (MBC), and nitrogen (MBN), along with MBC-to-SOC and MBN-to-TN ratio, were significantly higher in mixed stands with markedly positive admixing effects. We also found higher carbon source utilization ability and β−1, 4−N−acetylglucosaminidase, urease and acid phosphatase activities in mixed stands compared with the mono-species stands. Our results highlight that establishment of coniferous-broadleaf mixed forests may be a good management practice as coniferous-broadleaf mixture could accumulate higher stand biomass and return more litter, resulting in increasing soil microbial biomass and related functions for the long term in subtropical China.
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Liddle, Kaylin, Terence McGonigle, and Alexander Koiter. "Microbe Biomass in Relation to Organic Carbon and Clay in Soil." Soil Systems 4, no. 3 (July 8, 2020): 41. http://dx.doi.org/10.3390/soilsystems4030041.
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Soil microbes are key to nutrient cycling and soil formation, yet the impact of soil properties on microbe biomass remains unclear. Using 240 soil cores of 0–15 cm depth, taken at random points across six cattle-grazed pastures on an undulating landscape, we evaluated the biomass of microbes in soil as affected by naturally occurring variation in soil organic carbon (SOC), clay content, and local topography. The study pastures varied in historic land-use for crops or forage seeding. SOC was found to be greater in topographically low areas. In contrast, clay content was not related to topography, and clay deposition possibly varies with glaciation legacy. Microbial biomass carbon (MBC) was correlated positively with SOC, increasing from 700 mg kg−1 MBC at 25 g kg−1 SOC to 2240 mg kg−1 MBC at 90 g kg−1 SOC. Most likely, SOC promotes MBC through the release of water-soluble organic carbon. However, the response of MBC to clay content was negative, decreasing from 1340 mg kg−1 MBC at 5% clay to 880 mg kg−1 MBC at 30% clay. Small voids in association with clay particles likely restrict the access of microbes to SOC. The relationship between SOC and MBC illustrates the important role of SOC for soil function, in terms of nutrient availability and development of soil structure via the contribution of microbes. Lastly, there was considerable spatial variability in MBC across the 65 ha site, highlighting the importance of land-use histories and gradients in environmental variables, to determine the biomass of microbes in soil.
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Wu, Weifeng, Haiping Lin, Weijun Fu, Petri Penttinen, Yongfu Li, Jin Jin, Keli Zhao, and Jiasen Wu. "Soil Organic Carbon Content and Microbial Functional Diversity Were Lower in Monospecific Chinese Hickory Stands than in Natural Chinese Hickory–Broad-Leaved Mixed Forests." Forests 10, no. 4 (April 25, 2019): 357. http://dx.doi.org/10.3390/f10040357.
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To assess the effects of long-term intensive management on soil carbon cycle and microbial functional diversity, we sampled soil in Chinese hickory (Carya cathayensis Sarg.) stands managed intensively for 5, 10, 15, and 20 years, and in reference Chinese hickory–broad-leaved mixed forest (NMF) stands. We analyzed soil total organic carbon (TOC), microbial biomass carbon (MBC), and water-soluble organic carbon (WSOC) contents, applied 13C-nuclear magnetic resonance analysis for structural analysis, and determined microbial carbon source usage. TOC, MBC, and WSOC contents and the MBC to TOC ratios were lower in the intensively managed stands than in the NMF stands. The organic carbon pool in the stands managed intensively for twenty years was more stable, indicating that the easily degraded compounds had been decomposed. Diversity and evenness in carbon source usage by the microbial communities were lower in the stands managed intensively for 15 and 20 years. Based on carbon source usage, the longer the management time, the less similar the samples from the monospecific Chinese hickory stands were with the NMF samples, indicating that the microbial community compositions became more different with increased management time. The results call for changes in the management of the hickory stands to increase the soil carbon content and restore microbial diversity.
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Yao, Zengwang, Xudong Zhang, Xu Wang, Qi Shu, Xinmiao Liu, Hailong Wu, and Shenghua Gao. "Functional Diversity of Soil Microorganisms and Influencing Factors in Three Typical Water−Conservation Forests in Danjiangkou Reservoir Area." Forests 14, no. 1 (December 29, 2022): 67. http://dx.doi.org/10.3390/f14010067.
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As a key part of the forest ecosystem, soil microorganisms play extremely important roles in maintaining the ecological environment and the security of water quality in reservoir areas. However, it is not clear whether there are differences in the functional diversity of soil microorganisms in different types of water−conservation forests in reservoir areas, and which factors affect the functional diversity of soil microorganisms. In our study, the Biolog−Eco microplate technique was used to analyze the carbon source metabolic characteristics of soil microbial communities in three typical water−conservation forests and a non−forest land: Pinus massoniana−Quercus variabilis mixed forest (MF), Pinus massoniana forest (PF), Quercus variabilis forest (QF) and non−forest land (CK). The results showed that the average well color development (AWCD), the Shannon diversity index (SDI) and the richness index (S) of the three forest lands was significantly greater than that of the non−forest land (p < 0.05). The mean values of AWCD, SDI and S of the three forests had the same order (QF > PF > MF), but there was no significant difference among different types of forests. The microbial biomass carbon (MBC) and microbial biomass nitrogen (MBN) of QF and PF were higher than those of MF and CK, but the microbial biomass C/N ratio (MBC/MBN) was lower. The variance partitioning analysis (VPA) showed that 86.4% of the variation was explained by plant (community) diversity, soil physical and chemical properties and soil microbial biomass, which independently explained 10.0%, 28.9%, and 14.9% of the variation, respectively. The redundancy analysis (RDA) showed that total phosphorus (TP), microbial biomass carbon (MBC), total nitrogen (TN), number of plant species (Num) and alkali-hydro nitrogen (Wn) were the key factors affecting the functional diversity of soil microorganisms. This study confirmed that forest ecosystem is better than non−forest land in maintaining soil microbial function diversity. Moreover, Quercus variabilis forest may be a better stand type in maintaining the diversity of soil microbial functions in the study area.
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Muniz, Luciano Cavalcante, Beata Emöke Madari, José Benedito de Freitas Trovo, Ilka South de Lima Cantanhêde, Pedro Luiz Oliveira de Almeida Machado, Tarcísio Cobucci, and Aldi Fernandes de Souza França. "Soil biological attributes in pastures of different ages in a crop-livestock integrated system." Pesquisa Agropecuária Brasileira 46, no. 10 (October 2011): 1262–68. http://dx.doi.org/10.1590/s0100-204x2011001000021.
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The objective of this work was to evaluate the effect of the pasture (Urochloa brizantha) component age on soil biological properties, in a crop-livestock integrated system. The experiment was carried out in a Brazilian savannah (Cerrado) area with 92 ha, divided into six pens of approximately 15 ha. Each pen represented a different stage of the pasture component: formation, P0; one year, P1; two years, P2; three years, P3; and final with 3.5 years, Pf. Samples were taken in the 0-10 cm soil depth. The soil biological parameters - microbial biomass carbon (MBC), microbial biomass respiration (C-CO2), metabolic quotient (qCO2), microbial quotient (q mic), and total organic carbon (TOC) - were evaluated and compared among different stages of the pasture, and between an adjacent area under native Cerrado and another area under degraded pasture (PCD). The MBC, q mic and TOC increased and qCO2 reduced under the different pasture stages. Compared to PCD, the pasture stages had higher MBC, q mic and TOC, and lower qCO2. The crop-livestock integrated system improved soil microbiological parameters and immobilized carbon in the soil in comparison to the degraded pasture.
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Lu, Yan, and Hongwen Xu. "Distribution Characteristic of Soil Organic Carbon Fraction in Different Types of Wetland in Hongze Lake of China." Scientific World Journal 2014 (2014): 1–5. http://dx.doi.org/10.1155/2014/487961.
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Soil organic carbon fractions included microbial biomass carbon (MBC), dissolved organic carbon (DOC), and labile organic carbon (LOC), which was investigated over a 0–20 cm depth profile in three types of wetland in Hongze Lake of China. Their ecoenvironmental effect and the relationships with soil organic carbon (SOC) were analyzed in present experiment. The results showed that both active and SOC contents were in order reduced by estuarine wetland, flood plain, and out-of-lake wetland. Pearson correlative analysis indicated that MBC and DOC were positively related to SOC. The lowest ratios of MBC and DOC to SOC in the estuarine wetland suggested that the turnover rate of microbial active carbon pool was fairly low in this kind of wetland. Our results showed that estuarine wetland had a strong carbon sink function, which played important role in reducing greenhouse gas emissions; besides, changes of water condition might affect the accumulation and decomposition of organic carbon in the wetland soils.
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Liu, Bing Ru. "Relationship between Reaumuria soongorica Community Structure and Soil Quality of the Semiarid Loess Plateau, NW of China." Advanced Materials Research 183-185 (January 2011): 310–13. http://dx.doi.org/10.4028/www.scientific.net/amr.183-185.310.
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Reaumuria soongorica is the main dominant and constructive species of the desert shrub vegetation in the northwestern of China. The informations about changes in soil quality and vegetation structure togethor are available, which can provide valuable insights into the development of sustainable ecological systems that optimize production and maintain high environmental quality, but the variety of the plant community structure associate with dynamics of soil nutrient and microbial biomass are little known. In this study, five coverage levels of R. soongorica community were determined, while soil nutrients and microbial biomass were investigated. The results showed that the trends of plant species diversity (species richness) are ‘humped-back model’, soil organic carbon (SOC), total nitrogen (TN), soil microbial biomass C (MBC) and N (MBN) slightly increased with plant cover but not with plant species richness. MBC and MBN were positively correlated with SOC and TN (P<0.05), and plant cover showed positively correlated with soil nutrients and soil microbial biomass. It was concluded that vegetation restoration improved soil nutrient status and indirectly affected soil microbial biomass. However, the unilateral increase of vegetation cover will have less effect to soil quality.
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Yadav, Richi, Mridula Negi, and H. Vasistha. "Effect of fire on physicochemical and biological properties of soil under different plantations of rock phosphate mined area in Doon valley, India." Indian Journal of Forestry 34, no. 4 (December 1, 2011): 403–8. http://dx.doi.org/10.54207/bsmps1000-2011-675hn7.
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Soil physicochemical and biological properties of restored rock phosphate mined area of Maldeota in Doon valley were studied to evaluate the impact of fire. The soil texture of Maldeota varies from sandy loam to loamy sand. Soil organic carbon and soil microbial biomass was studied in a natural forest area and in a restored mined area at Maldeota. Soils samples were collected from both fire affected and unaffected sites. The objective of the present study was to evince the changes in soil properties after fire. Microbial biomass carbon in the burnt restored area found to be greater as compared to that of natural area. Soil moisture content and soil microbial quotient reveals that natural forest has good soil quality whereas the rest of the sites are devoid of good microbial quotient and moisture content. The Microbial Biomass Carbon (MBC) and soil organic carbon together can be considered more effective in estimating the reclamation efforts.
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Wang, Yong-Sheng, Shu-Lan Cheng, Gui-Rui Yu, Hua-Jun Fang, Jiang-Ming Mo, Min-Jie Xu, and Wen-Long Gao. "Response of carbon utilization and enzymatic activities to nitrogen deposition in three forests of subtropical China." Canadian Journal of Forest Research 45, no. 4 (April 2015): 394–401. http://dx.doi.org/10.1139/cjfr-2014-0445.
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Nitrogen (N) deposition has been shown to affect soil carbon (C) and N cycling in subtropical forests; however, the underlying microbial mechanisms are poorly understood. We used patterns of community-level physiological profiles and enzyme activities to assess the relative effects of the addition of four N levels (0, 50, 100, and 150 kg·ha−1·year−1) on the soil microbial community in three forest stands (pine, mixed, and broadleaf forests) in southern China, where the forests have been experimentally manipulated for over 8 years. In pine forests, N50 addition significantly increased microbial biomass carbon (MBC) concentration but decreased soil pH levels. N100 addition significantly increased soil peroxidase activity but decreased soil β-1,4-glucosidase activity. In broadleaf forests, N addition increased soil dissolved organic carbon (DOC) concentration and polyphenol oxidase activity but decreased soil MBC concentration and soil pH levels. N addition also significantly increased soil microbial metabolism activity (expressed as average well color development) in pine forest and broadleaf forest soils. However, the mixed forests responded slowly to N additions and exhibited no significant response of C-utilization profiles and soil enzyme activities. Principal component analysis of C-utilization data separated microbial communities with respect to N addition and forest successional stage. In addition, microbial C utilization was driven by soil pH levels. Although enzyme activities were correlated with soil MBC and microbial biomass nitrogen concentrations, stepwise regression results indicated that soil total carbon contents that were integrated with soil pH levels were key integrators of soil enzyme activities. Our results suggest that soil acidification due to N addition increased soil bacterial C utilization and enzyme activities.
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A. Martin, Jr, Artemio. "EFFECTS OF COVER CROPPPING ON NITROGEN DIOXIDE, CARBON DIOXIDE AND METHANE FLUXES AND SOIL ENZYME ACTIVITIES IN CORN-SOYBEAN ROTATION SYSTEM." Journal of BIMP-EAGA Regional Development 3, no. 2 (December 16, 2017): 40–52. http://dx.doi.org/10.51200/jbimpeagard.v3i2.1040.
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The effect of cover crops (ryegrass, hairy vetch, and oilseed radish) in terms of microbial biomass carbon (MBC), C and N mineralization, and enzymatic activities in a corn-wheat-soybean cropping systems under a Mollisol was evaluated. The distributions of total organic C (TOC), total Kjeldahl N (TKN), microbial biomass C (MBC), readily mineralizable C and N, and five enzyme activities (β-glucosidase, β-glucosaminidase, acid phosphatase, arylamidase, and fluorescein diacetate hydrolysis) involved in the cycling of C, N, P and S were studied in three soil depths (0-5. 5-10, 10-20 cm) while soil surface fluxes of carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) were estimated. Ryegrass showed higher activity in acid phosphatase, β-glucosidase and β-glucosaminidase. Ryegrass and hairy vetch significantly increased organic C and N, and MBC. Level of mineralized C and N were the same in ryegrass and hairy vetch. There was no clear variation in CO2, N2O and CH4 fluxes from the cover crop treatments. N2O fluxes increased with an increase in soil moisture. The negative CH4 fluxes manifest the soil as CH4 sink. No significant differences among cover crop treatments in terms of CO2-C, N2O-N and CH4-C emissions, a reflection that their emissions are highly variable. Empirical data on carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) fluxes are important in management systems to evaluate mitigation strategies, while microbial biomass and enzyme activities can be used as sensitive indicators of ecological stability.
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Mavi, Manpreet S., and Petra Marschner. "Salinity affects the response of soil microbial activity and biomass to addition of carbon and nitrogen." Soil Research 51, no. 1 (2013): 68. http://dx.doi.org/10.1071/sr12191.
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Addition of carbon (C) and nitrogen (N) to soil can enhance microbial tolerance to salinity, but it is not known if salinity changes the response of microbial activity and biomass to addition of C and N, or how nutrient addition affects microbial tolerance to salinity. We prepared salinity treatments of non-saline soil [electrical conductivity (EC1 : 5) 0.1 dS m–1] without salt addition or adjusted to four salinity levels (2.5, 5.0, 7.5, 10 dS m–1) using a combination of CaCl2 and NaCl. The soils were amended with 2.5 mg C g–1 as glucose or as mature wheat straw (C/N ratio 47 : 1), with NH4Cl added to glucose to achieve a C/N ratio similar to that of wheat straw, or with NH4Cl added to glucose or wheat straw to achieve a C/N ratio of 20. Soil respiration was measured over 30 days. Microbial biomass C and N (MBC, MBN), dissolved organic C (DOC), and total dissolved N (TDN) were measured on day 30. Cumulative respiration and MBC concentration decreased with increasing EC, less so with glucose than with wheat straw. The MBC concentration was more sensitive to EC than was cumulative respiration, irrespective of C source. Addition of N to glucose and wheat straw to bring the C/N ratio to 20 significantly decreased cumulative respiration and MBC concentration at a given EC. This study showed that in the short term, addition of a readily available and easily decomposable source of energy improves the ability of microbes to tolerate salinity. The results also suggest that in saline soils, irrespective of the C substrate, N addition has no impact, or a negative impact, on microbial activity and growth.
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Chen, Hao, Lu Lai, Xiaorong Zhao, Guitong Li, and Qimei Lin. "Soil microbial biomass carbon and phosphorus as affected by frequent drying–rewetting." Soil Research 54, no. 3 (2016): 321. http://dx.doi.org/10.1071/sr14299.
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Drying and rewetting (DRW) events are very common in arable land. However, it is not clear how the frequency of DRW stress history influences soil carbon (C) and phosphorus (P) dynamics under field conditions. In this study, an arable loam calcareous soil was treated with simulated farming practices that included wheat straw and nitrogen incorporation and three DRW cycles at intervals of 14 days during a 90-day experimental period of incubation at 25°C. The DRW events significantly increased cumulative CO2-C evolution, but the increase rate of cumulative CO2-C evolution declined with increasing DRW cycles. Microbial biomass C (MBC) and P (MBP) decreased by 9–55% and 9–29%, respectively, following each DRW event, but recovered to the level before DRW treatment within 7 days. Frequent drying and rewetting caused significant increases in both extractable organic C and NaHCO3-extractable P, by 10–112% and 10–18%, respectively. The fluctuation of the tested parameters became less with increasing frequency of DRW cycles. Changes in microbial biomass, either MBC or MBP, were poorly correlated with those of extractable organic C and NaHCO3-extractable P. Overall, frequent DRW cycles had much stronger and longer lasting impact on soil biomass P dynamics than biomass C. These findings may imply certain links among soil moisture, microbial activity and nutrient bioavailability that are important in water and nutrient management.
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Zhang, T. Q., C. F. Drury, and B. D. Kay. "Soil dissolved organic carbon: Influences of water-filled pore space and red clover addition and relationships with microbial biomass carbon." Canadian Journal of Soil Science 84, no. 2 (May 1, 2004): 151–58. http://dx.doi.org/10.4141/s02-030.
Full textAbstract:
Soil dissolved organic carbon (SDOC) plays an important role in organic C cycling and translocation of nutrients and pollutants in the soil profile. Soil microbial biomass C (MBC) has been used as an indicator of soil quality. Both SDOC and MBC may be affected by management practices and indigenous soil properties, which however are not fully understood. Using a laboratory incubation technique, we determined the effects of red clover (Trifolium pratense L.) addition and soil water saturation as expressed in water-filled pore space (WFPS, 20-95%) on soil SDOC and MBC in three soils from Ontario. The levels of SDOC were the greatest at 20% WFPS, and decreased with increase s in WFPS up to 95%. In comparison with the control, addition of red clover increased SDOC by up to 72% at 20% WFPS, but the effect was minimal or insignificant at WFPS above 50%. Reduction of SDOC with increases of WFPS both with and without red clover was attributed to the increased mineralization of labile organic C, as indicated by CO2 production. Regardless of the legume amendment, soil available N (e.g., mineral N), labile organic C (e.g. initial level of SDOC) or the variable derived from these two measurements, available C:N ratio, were the factors predominately affecting dynamics of SDOC at WPFS from 20 to 50% after 1-mo incubation and at WFPS from 20 to 65% with extended incubation to 3-mo. Soil factors affecting SDOC at WFPS above 85% were total N and pH without red clover, but changed to organic C and soil labile organic C with red clover. High levels of MBC were found to occur mostly with the high WFPS, and were enhanced by red clover addition only in the Perth silt loam. Soil dissolved organic C was significantly related to MBC with WFPS from 20 to 65% without red clover. No relationships between SDOC and MBC were found at WFPS above 65% without red clover and at WFPS from 20 to 95% with red clover. Soil factors affecting SDOC and the availabili ty of SDOC to microbial activity are WFPS dependent and related to soil legume amendment. Key words: Red clover, water-filled pore space, dissolved organic C, microbial biomass C, CO2 emission
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Mátyás, Bence, Judit Horváth, and János Kátai. "Comparative analysis of certain soil microbiological characteristics of the carbon cycle." Acta Agraria Debreceniensis, no. 69 (March 23, 2016): 137–41. http://dx.doi.org/10.34101/actaagrar/69/1802.
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In our researches, we examine the soil microbial parameters related to the carbon cycle. In this study, we compare the changes of microbial biomass carbon (MBC) and the soil CO2 production in soil samples which were taken in spring and autumn. The 30 years old long-term experiment of Debrecen-Látókép is continued in our experiments. The long-term fertilization experiment was set in 1983, and our sample was taken in spring 2014. The examinations of soil respiration processes and factors that influence soil respiration are required in optimal management. In our study, we interested to know how the growing levels of fertilization influence the soil respiration and microbial biomass carbon under non-irrigated and irrigated conditions in maize mono, bi, and triculture.
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Wang, Ruzhen, Linyou Lü, Courtney A. Creamer, Feike A. Dijkstra, Heyong Liu, Xue Feng, Guoqing Yu, Xingguo Han, and Yong Jiang. "Alteration of soil carbon and nitrogen pools and enzyme activities as affected by increased soil coarseness." Biogeosciences 14, no. 8 (April 27, 2017): 2155–66. http://dx.doi.org/10.5194/bg-14-2155-2017.
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Abstract. Soil coarseness decreases ecosystem productivity, ecosystem carbon (C) and nitrogen (N) stocks, and soil nutrient contents in sandy grasslands subjected to desertification. To gain insight into changes in soil C and N pools, microbial biomass, and enzyme activities in response to soil coarseness, a field experiment was conducted by mixing native soil with river sand in different mass proportions: 0, 10, 30, 50, and 70 % sand addition. Four years after establishing plots and 2 years after transplanting, soil organic C and total N concentrations decreased with increased soil coarseness down to 32.2 and 53.7 % of concentrations in control plots, respectively. Soil microbial biomass C (MBC) and N (MBN) declined with soil coarseness down to 44.1 and 51.9 %, respectively, while microbial biomass phosphorus (MBP) increased by as much as 73.9 %. Soil coarseness significantly decreased the enzyme activities of β-glucosidase, N-acetyl-glucosaminidase, and acid phosphomonoesterase by 20.2–57.5 %, 24.5–53.0 %, and 22.2–88.7 %, used for C, N and P cycling, respectively. However, observed values of soil organic C, dissolved organic C, total dissolved N, available P, MBC, MBN, and MBP were often significantly higher than would be predicted from dilution effects caused by the sand addition. Soil coarseness enhanced microbial C and N limitation relative to P, as indicated by the ratios of β-glucosidase and N-acetyl-glucosaminidase to acid phosphomonoesterase (and MBC : MBP and MBN : MBP ratios). Enhanced microbial recycling of P might alleviate plant P limitation in nutrient-poor grassland ecosystems that are affected by soil coarseness. Soil coarseness is a critical parameter affecting soil C and N storage and increases in soil coarseness can enhance microbial C and N limitation relative to P, potentially posing a threat to plant productivity in sandy grasslands suffering from desertification.
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Soretire, Adeniyi, Olalekan Sakariyawo, Oyinkansola Yewande, John Adesodun, Aderonke Akintokun, Paul Soremi, and Sunday Aderibigbe. "Changes in microbial biomass and grain yield of rice varieties in response to the alternate wet and dry water regime in the inland valley of derived savanna." Journal of Agricultural Sciences, Belgrade 64, no. 3 (2019): 239–53. http://dx.doi.org/10.2298/jas1903239s.
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This investigation tested the hypothesis that the alternate wet and dry (AWD) water regime would increase soil microbial biomass carbon (MBC), microbial biomass nitrogen (MBN) and microbial count. Variations in MBC, MBN and grain yield could be due to varietal differences in a derived savanna. Experiments (both pot and field ones) were conducted at the Federal University of Agriculture, Abeokuta (Latitude 7? 12? to 7? 20? N and Longitude 3? 20? to 3? 28? E), Nigeria in 2015. In both trials, the treatments consisted of water regimes (continuous flooding [control] and AWD imposed on lowland rice varieties [NERICA?L-19])and Ofada [local check] at the vegetative growth stage in three cycles. The design in both trials was a completely randomised and randomised complete block design for the pot and field experiments respectively, with three replicates. In the screen house, MBC and MBN were significantly higher in AWD than in continuously flooded soil, especially at the beginning of the AWD cycles. This could have caused nutrient pulses to sustain the improved performance of lowland rice under AWD. A converse pattern was observed in the field in the third cycle. Ofada rice had a significantly higher microbial count and MBC (cycle 1) than NERICA L-19, however, a converse pattern was observed in MBC (cycles 2 and 3) and MBN (cycle 1). Composition of their rhizodeposition and timing of cycles could explain the observed varietal differences in MBC and MBN.
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Wan, Zhong Mei. "Vertical Dynamics of Soil Enzyme Activities and Active Organic Carbon in a Freshwater Marsh in Sanjiang Plain, Northeast China." Advanced Materials Research 998-999 (July 2014): 1504–7. http://dx.doi.org/10.4028/www.scientific.net/amr.998-999.1504.
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To understand the influence of vertical dynamics of soil enzyme activities on the active carbon pool in Calamagrostis angustifolia wetland, the vertical distribution in 0-30cm depth of soil cellulase and amylase activities and active organic carbon fractions (microbial biomass carbon /MBC, easily oxidizable carbon/EOC) were measured and the relationship between soil enzyme activities and active organic carbon were analyzed. The results show that the enzyme activities and EOC and MBC contents in topsoil are the greatest. The soil cellulase and amylase activities and EOC and MBC contents show descending trends from surface layer to 30cm. The soil enzyme activities are significantly positive related to EOC and MBC contents. Therefore, with the increase of soil depth, the activities of cellulase and amylase obviously affect the soil active carbon pool. Furthermore, the cellulase activity of marsh soil has the strongest influence on soil active carbon pool.
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Xie, Wen Hao, Guo Mei Jia, and Fang Qing Chen. "The Soil Labile Organic Carbon Fractions at the Different Ages of Tea in Three Gorges Reservoir Area." Advanced Materials Research 864-867 (December 2013): 2645–48. http://dx.doi.org/10.4028/www.scientific.net/amr.864-867.2645.
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Soil total organic carbon (TOC), readily oxidizable C (ROC), and microbial biomass C (MBC) were determined at the different ages of tea in Three Gorges Reservoir area, China. The results showed that soil TOC and ROC in the 0-20cm decreased gradually with age of tea garden, whereas MBC had no significant difference among sites. OC, ROC, and MBC decreased readily with depth. Soil total organic C only showed a significantly positive relationship with readily oxidizable C. The age of tea showed a significantly negative relationship with TOC and ROC.
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Hossain, Mohammad Zaber, Md Rezaul Karim, Bina Rani Majumder, and Falguni Akter. "Microbial and enzymatic activity as influenced by existing cropping pattern in the soils of Ganges floodplain." Plant Science Today 6, no. 3 (July 18, 2019): 309–14. http://dx.doi.org/10.14719/pst.2019.6.3.545.
Full textAbstract:
Effect of multi cropping (Potato-Jute-Sweetgourd-T.Aman, Sweet gourd-Brinjal-Jute, Cauliflower-Radish-Lentil-Basil, Jute-Lentil-Mustard-Wheat and Sweetgourd-Turnip, designated as P-J-S-T, S-B-J, C-R-L-B, J-L-M-W and S-T, respectively) and mono cropping systems (orchard of Lychee, Teak, Turmeric and Banana) on microbial and enzymatic activity of Ganges floodplain soil was investigated. Organic carbon, microbial biomass carbon (MBC), microbial biomass nitrogen (MBN), soil respiration, total nitrogen and urease activity (UA) of the soils were examined. Upon examination it was observed that soils under mono cropping pattern (Lychee, Teak, and Banana) showed significantly (p?0.05) higher MBC, MBN and UA than those under multi cropping pattern. Highest values of MBC and UA found in teak plant were 95.44 milligram/kilogram (mgkg-1) and 6.51µg N released g-1day-1 respectively while for multi cropping pattern the respective values were 37.52 mgkg-1 and 2.23 µg N released g-1day-1 found in S-T and J-L-M-W cropping pattern. The highest MBN (12.70 mgkg-1) was obtained in soil where lychee was practiced. Multi cropping soil showed significantly (p?0.05) higher respiration rate than mono cropping soil and the highest rate was found 508.75 mg CO2 g-1day-1 in J-M-L-W cropping pattern. Turmeric showed the lowest respiration rate (120.75 mg CO2 g-1day-1) among the cropping pattern studied. Both MBC and UA showed positively significant relation with soil organic carbon, and total N at 0.01 % level. High microbial and enzymatic activity of mono cropping soil represent combined effect of vegetation and low tillage practices in soil.
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Barsotti, Joy L., Upendra M. Sainju, Andrew W. Lenssen, Zach J. Miller, and Patrick G. Hatfield. "Sheep Grazing Enhances Coarse Relative to Microbial Organic Carbon in Dryland Cropping Systems." Sustainable Agriculture Research 5, no. 2 (April 5, 2016): 1. http://dx.doi.org/10.5539/sar.v5n2p1.
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Sheep (<em>Ovis aries </em>L<em>.</em>) grazing, a cost-effective method of weed control compared with herbicide application and tillage, may influence soil C fractions by consuming crop residue and weeds and returning C through feces and urine to the soil. We examined the effect of three weed management practices (sheep grazing, herbicide application, and tillage) and two cropping sequences (continuous spring wheat [<em>Triticum aestivum </em>L.] [CSW] and spring wheat-pea [<em>Pisum sativum </em>L.]/barley [<em>Hordeum vulgare </em>L.] mixture hay-fallow [W-P/B-F]) on soil microbial biomass C (MBC), potential C mineralization (PCM), and particulate organic C (POC) in relation to soil organic C (SOC) at the 0- to 30-cm depth from 2009 to 2011 in southwestern Montana. The MBC at 0 to 5 cm was greater with tillage on CSW than tillage on W-P/B-F in 2009 and 2011, but was greater with herbicide application on CSW than tillage on CSW in 2010. The POC at 0 to 5 cm and 15 to 30 cm was greater with sheep grazing than herbicide application on CSW and W-P/B-F, but at 5 to 15 cm was greater with grazing on CSW. The MBC, PCM, and POC at all depths decreased from 2009 to 2011. Crop residue incorporation into the soil increased MBC with tillage on CSW. Lower proportions of labile than nonlabile organic matter through feces and urine probably reduced MBC at the soil surface, but increased POC with sheep grazing compared with herbicide application on CSW and W-P/B-F. Sheep grazing may increase coarse soil organic matter compared with microbial biomass in dryland cropping systems.
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Silva, Andréa Scaramal da, Arnaldo Colozzi Filho, André Shigueyoshi Nakatani, Sérgio José Alves, Diva de Souza Andrade, and Maria de Fátima Guimarães. "MICROBIAL CHARACTERISTICS OF SOILS UNDER AN INTEGRATED CROP-LIVESTOCK SYSTEM." Revista Brasileira de Ciência do Solo 39, no. 1 (February 2015): 40–48. http://dx.doi.org/10.1590/01000683rbcs20150185.
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Integrated crop-livestock systems (ICLs) are a viable strategy for the recovery and maintenance of soil characteristics. In the present study, an ICL experiment was conducted by the Instituto Agronômico do Paraná in the municipality of Xambre, Parana (PR), Brazil, to evaluate the effects of various grazing intensities. The objective of the present study was to quantify the levels of microbial biomass carbon (MBC) and soil enzymatic activity in an ICL of soybean (summer) and Brachiaria ruziziensis (winter), with B. ruziziensis subjected to various grazing intensities. Treatments consisted of varying pasture heights and grazing intensities (GI): 10, 20, 30, and 40 cm (GI-10, GI-20, GI-30, and GI-40, respectively) and a no grazing (NG) control. The microbial characteristics analysed were MBC, microbial respiration (MR), metabolic quotient (qCO2), the activities of acid phosphatase, β-glucosidase, arylsuphatase, and cellulase, and fluorescein diacetate (FDA) hydrolysis. Following the second grazing cycle, the GI-20 treatment (20-cm - moderate) grazing intensity) contained the highest MBC concentrations and lowest qCO2 concentrations. Following the second soybean cycle, the treatment with the highest grazing intensity (GI-10) contained the lowest MBC concentration. Soil MBC concentrations in the pasture were favoured by the introduction of animals to the system. High grazing intensity (10-cm pasture height) during the pasture cycle may cause a decrease in soil MBC and have a negative effect on the microbial biomass during the succeeding crop. Of all the enzymes analyzed, only arylsuphatase and cellulase activities were altered by ICL management, with differences between the moderate grazing intensity (GI-20) and no grazing (NG) treatments.
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Saraiva, Talyta Carine da Silva, Sabrina Hermelindo Ventura, Eudemio Sousa Brito Junior, Sandra Mara Barbosa Rocha, Romario Martins Costa, Arthur Prudencio de Araujo Pereira, Ricardo Silva De Sousa, Jay Prakash Verma, Paul J. Van den Brink, and Ademir Sergio Ferreira Araujo. "Temporal Stability of Soil Microbial Properties in Responses to Long-Term Application of Compost Obtained from Tannery Sludge." Sustainability 14, no. 24 (December 14, 2022): 16736. http://dx.doi.org/10.3390/su142416736.
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Successive applications of compost obtained from tannery sludge affected the soil microbial biomass and activity. However, the effect of this practice on the temporal stability of soil microbial properties is not known. This study evaluated the temporal stability of microbial biomass, respiration, and enzymes activities in soil with successive applications of compost obtained from tannery sludge. Soil samples (0–10 cm depth) were collected from sites with successive application of compost at the lowest (2.5 ton/ha) and highest (20 ton/ha) rates, including the control (0 ton/ha). Soil microbial biomass carbon (MBC) and nitrogen (MBN), respiration, dehydrogenase, and urease activities were evaluated at 0, 30-, 60-, 90-, and 150-days post-application. The soil microbial properties varied as per treatments and sampling time. The principal response curve showed higher variation of soil microbial properties in the treatment having highest rate of compost. This analysis showed dehydrogenase, urease, and MBC as the most responsive parameters. The temporal stability of soil microbial parameters showed highest values at the lowest rate of compost. This study showed that the successive application of compost contributed to a decrease in variation and increase in temporal stability of soil microbial properties at the lowest rate.
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Zhou, Hua, Wan Tai Yu, and Ying Zhao. "Total and Labile Carbon in Alfisol Soil Amended with Plant Residual and Livestock Manure." Advanced Materials Research 988 (July 2014): 411–15. http://dx.doi.org/10.4028/www.scientific.net/amr.988.411.
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In a situ buried-bag experiment, the seasonal dynamics of soil total organic carbon (TOC) and labile organic carbon in soil amended with maize stalk (MS), chicken manure (CM), pig manure (PM) and mixture of them (MI) were studied in one year. MS with a low N content and high C/N ratio decomposed a little faster than other materials with low C/N ratios. Labile carbon pool – microbial biomass carbon (MBC) and light fraction of organic carbon (LFOC) exhibited an absolute difference in the 365-day incubation period: MS in MBC showed a gentle ascendant tendency; however, CM and PM displayed a rapid decrease. The concentrations of LFOC in all the treatments decreased coincidently nevertheless. MBC was more sensitive to organic material addition than other labile pools, despite of its low level.
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Sharma, Sandeep, Jatinder Kaur, H. S. Thind, Yadvinder Singh, Neha Sharma, and Kirandip Kirandip. "A framework for refining soil microbial indices as bioindicators during decomposition of various organic residues in a sandy loam soil." Journal of Applied and Natural Science 7, no. 2 (December 1, 2015): 700–708. http://dx.doi.org/10.31018/jans.v7i2.669.
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Assessment of soil quality is an invaluable tool in determining the sustainability and environmental impact of agricultural ecosystems. Soil microbial indices like microbial biomass and microbial activity are important criteria for the determination of soil quality. Laboratory incubation study was undertaken to examine the influence of eight crop residues widely varying in biochemical composition on the periodic changes in important soil microbial indices {(microbial (Cmic: Corg), metabolic (qCO2), carbon mineralization (qC) and microbial biomass change rate (qM) quotients)} at 28 days and 63 days after incubation (DAI) in a sandy loam soil. A. sativa amended soil showed maximum soil respiration rate (14.23 mg CO2-C g-1 soil day-1) whereas T. aestivum amended soil showed maximum microbial biomass C (790 µg/g). The metabolic quotient among different crop residues ranged from 11.1 to 19.8 μg CO2-C μg-biomass-C-1 h-1 at 63 DAI. The results indicate that incorporation of different crop residues has positive effect on microbial flora and their activity. Microbial quotient (Cmic:Corg) was significantly positively correlated with microbial biomass carbon (MBC), qC and qM. The study suggests that the biochemical composition of different crop residues seems to be of better option for long term sustainable crop production with maintenance of soil quality in a sandy loam soil.
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Zhang, Yang, Pedro N. Carvalho, Tao Lv, Carlos Arias, Hans Brix, and Zhanghe Chen. "Microbial density and diversity in constructed wetland systems and the relation to pollutant removal efficiency." Water Science and Technology 73, no. 3 (October 21, 2015): 679–86. http://dx.doi.org/10.2166/wst.2015.542.
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Microbes are believed to be at the core of the wastewater treatment processes in constructed wetlands (CWs). The aim of this study was to assess the microbial biomass carbon (MBC) and Shannon's diversity index (SDI) in the substrate of CWs planted with Phragmites australis, Hymenocallis littoralis, Canna indica and Cyperus flabelliformis, and to relate MBC and SDI to the pollutant removal in the systems. Significant higher MBC was observed in CWs with H. littoralis and C. indica than in CWs with P. australis, and the MBC differed with season and substrate depth. The microbial community in the wetlands included four phyla: Cyanobacteria, Proteobacteria, Chloroflexi, and Acidobacteria, with a more diverse community structure in wetlands with C. flabelliformis. The MBC in the substrate and the SDI of the 15–20 cm depth correlated with the removal of biochemical oxygen demand, NH4-N and NO3-N. Our results indicate that substrate SDI and MBC can both be regarded as bioindicators of the pollutant removal ability in CWs.
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He, Huan, Yixuan Liu, Yue Hu, Mengqi Zhang, Guodong Wang, and Weibo Shen. "Soil Microbial Community and Its Interaction with Soil Carbon Dynamics Following a Wetland Drying Process in Mu Us Sandy Land." International Journal of Environmental Research and Public Health 17, no. 12 (June 12, 2020): 4199. http://dx.doi.org/10.3390/ijerph17124199.
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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.
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Kaur, Joginder, O. P. Choudhary, and Bijay-Singh. "Microbial biomass carbon and some soil properties as influenced by long-term sodic-water irrigation, gypsum, and organic amendments." Soil Research 46, no. 2 (2008): 141. http://dx.doi.org/10.1071/sr07108.
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Long-term sodic-water irrigation may adversely affect the quality of soil organic carbon along with some soil properties. The extent to which the adverse effects can be ameliorated through the use of gypsum and amendments needs to be known. Soil properties and microbial biomass carbon (MBC) were studied after 14 years of sodic water (SW) irrigation and application of different levels of gypsum, farmyard manure (FYM), green manure (GM), and wheat straw (WS) to a sandy loam soil. Irrigation with SW increased pH, electrical conductivity, sodium adsorption ratio, exchangeable sodium percentage (ESP), and bulk density, and decreased final infiltration rate of soil. Application of gypsum and organic amendments reversed these trends. Decrease in MBC due to SW irrigation was from 132.5 to 44.6 mg/kg soil in the 0–75 mm soil layer and from 49.0 to 17.3 mg/kg soil in the 75–150 mm soil layer. Application of gypsum and organic amendments significantly increased MBC; GM and FYM were more effective than WS. Changes in soil ESP explained 85 and 75% variation in MBC in the unamended and organically amended SW treatments, respectively. Soil pH as additional variable improved the predictability of MBC to 96% and 77%. Irrigation with SW reduced yield of rice plus wheat by 5 t/ha. Application of gypsum and organic amendments significantly increased the rice and wheat yield; it was significantly correlated with MBC (r = 0.56**, n = 60). It confirms that MBC rather than organic C is a more sensitive indicator of environmental stresses in soils caused by long-term sodic water irrigation.
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Vahedi, Roghayeh, MirHassan Rasouli-Sadaghiani, Mohsen Barin, and Ramesh Raju Vetukuri. "Interactions between Biochar and Compost Treatment and Mycorrhizal Fungi to Improve the Qualitative Properties of a Calcareous Soil under Rhizobox Conditions." Agriculture 11, no. 10 (October 13, 2021): 993. http://dx.doi.org/10.3390/agriculture11100993.
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Most calcareous soils have relatively low levels of organic matter. To evaluate the effect of pruning waste biochar (PWB) and pruning waste compost (PWC) combined with arbuscular mycorrhizal fungi (AMF) on the biological indices, a rhizobox study on wheat using a completely randomized design was conducted under greenhouse conditions. The studied factors included the source of organic material (PWB, PWC, and control), the microbial inoculation (+AMF or −AMF), and the zone (rhizosphere and non-rhizosphere soil). At the end of the plant growth period, organic carbon (OC), microbial biomass carbon (MBC), microbial biomass phosphorous (MBP), microbial respiration (BR), substrate-induced respiration (SIR), and alkaline (ALP) and acid (ACP) phosphatase enzyme activities in the rhizosphere and non-rhizosphere soils were determined. Simultaneous application of a source of organic matter and AMF inoculation significantly increased the OC and biological indices of soil relative to those observed when applying organic matter without AMF inoculation. Additionally, MBC, MBP, ACP, and ALP enzymes activities in the rhizosphere zone were significantly higher than in the non-rhizosphere. AMF increased BR and SIR levels in the rhizosphere by 13.06% and 7.95% compared to those in the non-rhizosphere, respectively. It can be concluded that PWC and PWB can improve soil biological properties by increasing microbial activity.
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Selvaraj*, Mohan, and Mathieu Ngouajio. "Effects of Cover Crops on Soil Microbial Biomass in Vegetable Cropping Systems." HortScience 39, no. 4 (July 2004): 871A—871. http://dx.doi.org/10.21273/hortsci.39.4.871a.
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The inclusion of cover crops into cropping systems may influence soil microbial activity which is crucial to sustained crop production. A study was conducted to measure short term effects of summer and winter cover crops on soil microbial biomass carbon (MBC) in a cucumber-tomato rotation system. The experiment was established in Summer 2002 as a factorial of summer cover crops (planted either as fallow or after harvest of cucumbers) and winter cover crops (planted in September). The design was a split-block with four replications. The main plot factor was summer cover crop and consisted of five treatments; sorghum sudangrass fallow (SGF), cowpea fallow (CPF), sorghum sudangrass after cucumber (SGC), cowpea after cucumber (CPC) and bareground fallow (BGF). The sub-plot factor was winter cover crop and consisted of three treatments including cereal rye (CR), hairy vetch (HV) and bareground (BG). In spring of 2003, soil samples were collected in each treatment at 30 days before (30 DBI), 2 days after (2 DAI) and 30 days after (30 DAI) cover crop incorporation. MBC was measured using the chloroform fumigation-incubation method. Both summer and winter cover crops affected soil microbial activity. MBC in the summer cover crop treatments at 30 DBI was 47.7, 51.4, 49.2, 43.7 and 42.5 μg·g-1 soil for SGF, CPF, SGC, CPC and BGF, respectively. At 30 DAI, 113.1, 88.9, 138.5, 105.6, and 109.3 μg·g-1 soil was obtained in SGF, CPF, SGC, CPC, and BGF plots, respectively. Soil MBC was similar at 2 DAI in the summer cover crop treatments. Among winter treatments MBC was similar at 30 DBI and 30 DAI, but significant at 2 DAI with values of 62.8, 53.3, 59.3 μg·g-1 soil for CR, BG, and HV, respectively.
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Pereira, David Gabriel Campos, Mickaelly Jordanya Guimarães Silva, Maickon Wilhian Pereira Meira, Helena Souza Nascimento Santos, José Augusto dos Santos Neto, Marcio Mahmoud Megda, and Michele Xavier Vieira Megda. "Microbial activity and carbon rates the soil in response to the application of potassium sources." Acta Scientiarum. Biological Sciences 44 (May 13, 2022): e58248. http://dx.doi.org/10.4025/actascibiolsci.v44i1.58248.
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The continuous use of KCl may not be sustainable in the long term in agricultural systems. High doses used in crops accumulate in the soil and plants, hindering the metabolic processes of soil organisms. This study assessed the soil microbial activity in response to the application of K sources in banana crop and effects on microbial C. The experimental design was completely randomized with four K sources: potassium nitrate (KNO3), potassium chloride (KCl), potassium sulfate (K2SO4), and monopotassium phosphate (KH2PO4) at 200 mg kg-1 of K2O, besides the control (without K) and combinations KCl:K2SO4. KCl application increased microbial activity 7 days after incubation, with gradual reduction over time. The isolated application of K2SO4 and the combination KCl: K2SO4 at the ratio 60: 40% increased total CO2 released by the microbiota. K2SO4 source had the highest microbial biomass C (MBC), as well as the 60: 40 combinations. Isolated application of K sources, especially with high chloride concentration, reduces the soil microbial activity and MBC.
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Edenborn, S. L., A. J. Sexstone, Y. Sutanto, and J. A. Chapman. "Relationships among Contrasting Measurements of Microbial Dynamics in Pasture and Organic Farm Soils." Applied and Environmental Soil Science 2011 (2011): 1–10. http://dx.doi.org/10.1155/2011/537459.
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Soil bacteria exhibit short-term variations in community structure, providing an indication of anthropogenic disturbances. In this study, microbial biomass carbon (MBC), potentially mineralizable nitrogen (PMN), community level physiological profiling (CLPP), and culture-dependent DGGE (CD DGGE) fingerprinting of the 16S rRNA gene were used to compare microbial communities in organic farm and pasture soils subjected to differing agronomic treatments. Correlation analyses revealed significant relationships between MBC, PMN, and data derived from microbial community analyses. All measures separated soil types but varied in their ability to distinguish among treatments within a soil type. Overall, MBC, PMN, and CLPP were most responsive to compost and manure amendments, while CD DGGE resolved differences in legume cropping and inorganic fertilization. The results support the hypothesis that culturable soil bacteria are a responsive fraction of the total microbial community, sensitive to agronomic perturbations and amenable to further studies aimed at linking community structure with soil functions.
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Lu, Rui, Xiao Ying Peng, and Ming Quan Yu. "Soil Carbon Mineralization and Microbial Biomass Carbon of In Situ and Exchange-Location Incubation in Forest along Urban-Rural Gradient." Applied Mechanics and Materials 707 (December 2014): 237–42. http://dx.doi.org/10.4028/www.scientific.net/amm.707.237.
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Urbanization in high-speed nowadays is changing soil carbon dynamic. Soil carbon mineralization (Cm) and microbial biomass carbon (MBC) of in situ and exchange-location incubation was characterized along urban-rural gradient in Nanchang, China. As a result, soil Cm and MBC of in situ incubation were higher in urban than in suburban, which were significantly higher than those in rural area (P<0.05), at the same time, urban soils incubating in rural area mineralized about 1.8 times the amount of carbon than rural soils incubating in rural area; MBC in soils of exchange-location incubation exhibited a significant decrease tendency with area farther away from urban as well (P<0.05), while there was no significant difference observed in Cm of soils from the same origin incubating in different area between urban, suburban and rural (P>0.05). The result indicated that urban soils have potential for higher losses of carbon than rural soils.
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de Lima, Sebastião Ferreira, Vinicius Andrade Secco, Cátia Aparecida Simon, Antônio Marcos Miranda Silva, Eduardo Pradi Vendruscolo, Maria Gabriela de Oliveira Andrade, Lucymara Merquides Contardi, Ana Paula Leite de Lima, Meire Aparecida Silvestrini Cordeiro, and Mariele Silva Abreu. "Microbiological Attributes and Performance of the Bacterial Community in Brazilian Cerrado Soil with Different Cover Crops." Sustainability 13, no. 15 (July 26, 2021): 8318. http://dx.doi.org/10.3390/su13158318.
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Soil microbiological indicators are essential tools to understand how the management with cover crops interferes in the activity and the soil microbial community. Thus, the objective of the study was to evaluate microbiological attributes and performance of the bacterial community in the soil of the Brazilian Cerrado with different cover crops. The experiment was performed in a randomized block design, evaluating seven cover crops, Sorghum bicolor, Crotalaria ochroleuca, Pennisetum americanum, Panicum miliaceum, Raphanus sativus, Urochloa brizantha, Urochloa ruziziensis, and a fallow area. Cover aerial biomass dry weight (CB), microbial biomass carbon (MBC), basal soil respiration (BR), metabolic quotient (qCO2), and abundance and structure of bacterial community based on the rrs 16S rRNA gene were evaluated. In the soil cultivated with S. bicolor there was the highest CB and MBC at the same time as there was less microbial activity (lower BR and qCO2). The structure of the bacterial community was more differentiated in soils cultivated with S. bicolor, P. americanum, and C. ochroleuca. The MBC was more associated with cover crops of the Urochloa genus, while BR was positively correlated with S. bicolor. Bacterial abundance was positively correlated with P. miliaceum.
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Oliveira, Willian Roberson Duarte de, Maria Lucrecia Gerosa Ramos, Arminda Moreira de Carvalho, Thais Rodrigues Coser, Antônio Marcos Miranda Silva, Manuel Messias Lacerda, Kleberson Worslley Souza, Robélio Leandro Marchão, Lourival Vilela, and Karina Pulrolnik. "Dynamics of soil microbiological attributes under integrated production systems, continuous pasture, and native cerrado." Pesquisa Agropecuária Brasileira 51, no. 9 (September 2016): 1501–10. http://dx.doi.org/10.1590/s0100-204x2016000900049.
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Abstract The objective of this work was to evaluate the dynamics of soil microbiological attributes under integrated production systems, continuous pasture, and native cerrado. The study was conducted in a transition area from crop to livestock. Four areas with different land uses were evaluated: an integrated crop-livestock-forestry system (ICLFS), cultivated with Eucalyptus urograndis alley cropping, spaced 2x2 m between plants and 22 m between alleys; an integrated crop-livestock system (ICLS); besides two adjacent areas of native cerrado and continuous pasture, used as a reference. For the assessment of microbiological attributes, soil samples were taken in the 0.00-0.10, 0.10-0.20, and 0.20-0.30-m layers, in February 2012 and February 2014 (rainy season), and in July 2012 and September 2013 (dry season). In general, soil under native cerrado had the highest microbial biomass carbon (MBC) levels, while under the ICLFS it had the lowest ones. The ICLS increased MBC and microbial coefficient in the deeper soil layers, after two years of establishment. Basal respiration, microbial biomass nitrogen, and MBC are the soil microbiological attributes better able to differentiate the evaluated systems.
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Morales, Diana, Mónica Machado Vargas, Michele Pottes de Oliveira, Bruna Lunarde Taffe, Jucinei Comin, Claudio Roberto Soares, and Paulo Lovato. "Response of soil microbiota to nine-year application of swine manure and urea." Ciência Rural 46, no. 2 (November 3, 2015): 260–66. http://dx.doi.org/10.1590/0103-8478cr20140565.
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ABSTRACT: Manure fertilization is a common practice, but little is known about its impacts on soil microbial activity and organic matter. Aiming to evaluate soil microbial response to nine years of successive applications of swine manure, organic carbon (TOC), total nitrogen (TN), pH, microbial biomass carbon (MBC), basal respiration (BR), metabolic quotient (qCO2), and enzyme (ß-glucosidase, phosphatase, arylsulphatase, and FDA) activities were measured in the 0-10cm soil layer, in a no-tillage system. Treatments were: control soil without fertilization (C), and application of two doses (104 and 209kg of N ha-1year-1) of urea (U1 and U2), pig slurry (PS1 and PS2) and deep litter (DL1 and DL2). TOC, TN, soil pH, MBC, and BR increased in soil fertilized with DL, and were lower in U treatments. Soils with U and DL application had higher qCO2, related to different sources of stressors like nutrient imbalance. Phosphatase and ß-glucosidase activities were not affected by treatments, increased with time, and had a strong correlation with MBC. We conclude that long-term swine manure applications increase microbial activity and soil organic matter, mainly in DL form; while urea applications have negative impacts on these indicators.
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Chantigny, Martin H., Denis A. Angers, and Chantal J. Beauchamp. "Active carbon pools and enzyme activities in soils amended with de-inking paper sludge." Canadian Journal of Soil Science 80, no. 1 (February 1, 2000): 99–105. http://dx.doi.org/10.4141/s99-050.
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Application of paper mill wastes generally improves soil organic matter content, biological activity and physical properties. However, the impact of large application rates (>50 Mg ha−1) on soil microflora and their activity has not been assessed. A field study was undertaken on a well-drained clay loam and a poorly drained silty clay loam amended with de-inking paper sludge (DPS) at rates of 0 (control), 50 or 100 Mg ha−1. K2SO4-extractable C (Cext), soil water content (SWC), microbial biomass C (MBC) and different enzyme activity rates were periodically measured in soil during 1075 d following DPS incorporation. Compared with control soils, Cext content increased by 100 to 200%, and soil water content increased by 35% following incorporation of DPS at 100 Mg ha−1. Those differences decreased in time as DPS decomposed. Soil MBC increased proportionally with the rate of DPS amendment and was about twice the amount in soils amended with 100 Mg ha−1 compared with the control. Microbial quotient (ratio of MBC to total soil organic C) was greater in DPS-amended than in control soils until day 370, reflecting the input of labile C from DPS. Compared with the control, fluorescein diacetate hydrolysis and alkaline phosphatase activity rates increased by 40 to 100% when adding 50 Mg DPS ha−1. However, the rates were similar for 50 and 100 Mg DPS ha−1. We concluded that DPS promoted microbial growth and activity in the soil by improving C and water availability. However, levelling off of enzyme activity at a DPS loading rate above 50 Mg ha−1 could reflect changes in soil microbial community, or some kinetic interference or nutrient deficiency induced by excessive C input. Key words: Microbial biomass, active carbon, soil enzyme, paper sludge
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Wang, Jingjing, Jun Cui, Zhen Teng, Wei Fan, Mengran Guan, Xiaoya Zhao, and Xiaoniu Xu. "Effects of simulated nitrogen deposition on soil microbial biomass and community function in subtropical evergreen broad-leaved forest." Forest Systems 28, no. 3 (November 12, 2019): e018. http://dx.doi.org/10.5424/fs/2019283-15404.
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Aim of the study: The aim of this study was to examine the effects of a 5-year simulated nitrogen (N) deposition on soil microbial biomass carbon (MBC), nitrogen (MBN), microbial community activity and diversity in subtropical old-growth forest ecosystems.Area of study: The study was conducted in forest located at subtropical forest in Anhui, east China.Material and methods: Three blocks with three fully randomized plots of 20 m × 20 m with similar forest community and soil conditions were established. The site applied ammonium nitrate (NH4NO3) to simulate N deposition (50 and 100 kg N ha−1 year −1). From three depths (0–10, 10–20 and 20–30 cm), were collected over four seasons (December, March, June and September), and then measured by community-level physiological profiles (CLPPs).Main results: N addition had no significant effect on MBC and MBN. The spatiotemporal variations in MBC and MBN were controlled by seasonality and soil depth. Soil microbial activities and diversity in the growing season (June and September) were apparently higher than the dormant season (March and December), there were significantly lower diversity indices found following N addition in September. However, N addition enhanced microbial activities and increased diversity indices in the dormant season. Redundancy analysis showed that pH, soil moisture, NO3--N and total phosphorus were the most important factors controlling the spatial pattern of microbial metabolic activity.Research highlights: These results suggest that soil microbial community function is more easily influenced than microbial biomass. The site has a trend of P-limited or near-N saturation, and will threaten the whole forest ecosystem with the increasing duration of N addition.Keywords: Nitrogen deposition; Seasonality; Soil microbial biomass; Microbial community; Subtropical old-growth forest.
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Wang, Qiuju, Xin Liu, Jingyang Li, Xiaoyu Yang, and Zhenhua Guo. "Straw application and soil organic carbon change: A meta-analysis." Soil and Water Research 16, No. 2 (April 9, 2021): 112–20. http://dx.doi.org/10.17221/155/2020-swr.
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Straw return is considered an effective way to improve the soil organic carbon (SOC) content of farmland. Most studies have suggested that a straw application increases the SOC content; however, some suggest that a straw application reduces the SOC content when used in combination with mineral fertilisation. Therefore, a meta-analysis of the effect of a straw application on the SOC change is needed. This study comprises a meta-analysis of 115 observations from 65 research articles worldwide. Straw applications can significantly increase the proportion of the SOC in the soil. Straw applications caused a significant microbial biomass carbon (MBC) increase in tropical and warm climatic zones. The MBC increase was higher than the SOC increase. For agriculture, the most important soil functions are the maintenance of the crop productivity, the nutrient and water transformation, the biological flora and activity, and the maintenance of the microbial abundance and activity. These functions should be prioritised in order to maintain the SOC function and services. Straw applications should not be excessive, especially when combined with mineral fertilisation, in order to avoid the loss of carbon from the straw in the form of greenhouse gases. A large amount of unused fertiliser also leads to a series of environmental problems.