Journal articles on the topic 'Soil microbial biomass'
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1
Pan, Yunlong, Fei Fang, and Haiping Tang. "Patterns and Internal Stability of Carbon, Nitrogen, and Phosphorus in Soils and Soil Microbial Biomass in Terrestrial Ecosystems in China: A Data Synthesis." Forests 12, no. 11 (November 9, 2021): 1544. http://dx.doi.org/10.3390/f12111544.
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Inspired by the strict constraint ratio (relatively low variability) between carbon (C), nitrogen (N), and phosphorus (P) in global soils and soil microbial biomass, our study explores the biogeographic distribution of C:N:P stoichiometric ratios in soils and soil microbial biomass in China and seeks to identify areas with similar ratios. Our study also attempts to determine the impacts of soil and soil microbial biomass C:N:P in China and the factors determining the ratio. The element concentrations may vary in each phylogenetic group of soils and soil microbial communities in China’s terrestrial ecosystems, as they do in global terrestrial ecosystems. However, on average, the C:N:P ratios for soil (66:5:1) and soil microbial biomass (22:2:1) are highly constrained within China. Soil microbial biomass C, N, and P concentrations have relatively weak internal stability, while soil microbial biomass C:N, C:P, and N:P ratios do not have internal stability at the national scale and in different terrestrial ecosystems of China. Unlike plant N:P, which can be used as the basis for evaluations of nutrient restrictions, the use of soil or soil microbial biomass N:P to evaluate soil nutrients is not universal. Latitude is the main factor influencing the patterns of soil C, N, and P. Longitude is the main factor determining the patterns of soil microbial biomass C, N, and P. pH is the main nonzonal factor affecting the patterns of soil and soil microbial biomass C, N, and P. The findings of this study are helpful in understanding the spatial pattern of soils and soil microbial biomass and their influencing factors in regions with complex ecosystems.
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Jenkinson, D. "Measuring soil microbial biomass." Soil Biology and Biochemistry 36, no. 1 (January 2004): 5–7. http://dx.doi.org/10.1016/j.soilbio.2003.10.002.
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Murphy, D. V., G. P. Sparling, and I. R. P. Fillery. "Stratification of microbial biomass C and N and gross N mineralisation with soil depth in two contrasting Western Australian agricultural soils." Soil Research 36, no. 1 (1998): 45. http://dx.doi.org/10.1071/s97045.
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The distribution of microbial biomass C and N and the decline in gross N mineralisation and NH4+ consumption with soil depth was investigated in 2 soils with different soil texture and land use. Soils were from an annual pasture on a loamy sand and from a sandy clay loam previously cropped with wheat. Intact soil cores were collected from the surface 0–10 cm in steel tubes and were sampled in 2·5 cm layers. Disturbed soil down to 50 cm was collected in 10 cm sections using a sand auger. Microbial biomass was estimated by chloroform fumigation and 0·5 M K2SO4 extraction. Microbial biomass C was determined from the flush in ninhydrin-positive compounds, and microbial biomass N from the flush in total soluble N after K2S2O8 oxidation. Gross N mineralisation and NH4+ consumption were estimated by 15N isotopic dilution using 15NH3 gas injection to label the soil 14NH4+ pool with 15N. The pattern of distribution of the microbial biomass and the rate of N transformations were similar for both soils. There was a rapid decline in microbial biomass C and N and gross N mineralisation with soil depth. Approximately 55% of the microbial biomass, 70–88% of gross N mineralisation, and 46–57% of NH4+ consumption was in the surface 0–10 cm in both soils. There was also a stratification of microbial biomass and gross N mineralisation within the 0–10 cm layer of intact soil cores. It was estimated that one-quarter of the total microbial biomass and at least one-half of the total gross N mineralisation within the soil profiles (0–50 cm) was located in the surface 2·5 cm layer. These results demonstrate the importance of the surface soil layer as a major source of microbial activity and inorganic N production. There was a strong correlation between the distribution of microbial biomass and the gross rate of mineralisation of soil organic N within the soil profile.
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Carpio, María José, Carlos García-Delgado, Jesús María Marín-Benito, María Jesús Sánchez-Martín, and María Sonia Rodríguez-Cruz. "Soil Microbial Community Changes in a Field Treatment with Chlorotoluron, Flufenacet and Diflufenican and Two Organic Amendments." Agronomy 10, no. 8 (August 8, 2020): 1166. http://dx.doi.org/10.3390/agronomy10081166.
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The soil microbial activity, biomass and structure were evaluated in an unamended (S) and organically amended soil treated with two commercial formulations of the herbicides chlorotoluron (Erturon®) and flufenacet plus diflufenican (Herold®) under field conditions. Soils were amended with spent mushroom substrate (SMS) or green compost (GC). Soil microbial dehydrogenase activity (DHA), biomass and structure determined by the phospholipid fatty acid (PLFA) profiles were recorded at 0, 45, 145, 229 and 339 days after herbicide treatment. The soil DHA values steadily decreased over time in the unamended soil treated with the herbicides, while microbial activity was constant in the amended soils. The amended soils recorded higher values of concentrations of PLFAs. Total soil microbial biomass decreased over time regardless of the organic amendment or the herbicide. Herbicide application sharply decreased the microbial population, with a significant modification of the microbial structure in the unamended soil. In contrast, no significant differences in microbial biomass and structure were detected in S + SMS and S + GC, untreated or treated with herbicides. The application of SMS and GC led to a significant shift in the soil microbial community regardless of the herbicides. The use of SMS and GC as organic amendments had a certain buffer effect on soil DHA and microbial biomass and structure after herbicide application due to the higher adsorption capacity of herbicides by the amended soils.
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Mühlbachová, G. "Potential of the soil microbial biomass C to tolerate and degrade persistent organic pollutants." Soil and Water Research 3, No. 1 (March 21, 2008): 12–20. http://dx.doi.org/10.17221/2096-swr.
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A 12-day incubation experiment with the addition of glucose to soils contaminated with persistent organic pollutants (POPs) was carried out in order to estimate the potential microbial activities and the potential of the soil microbial biomass C to degrade 1,1,1-trichloro-2,2-bis(p-chlorophenyl) ethane (DDT), polychlorinated biphenyls (PCB) and polycyclic aromatic hydrocarbons (PAHs). The microbial activities were affected in different ways depending on the type of pollutant. The soil organic matter also played an important role. The microbial activities were affected particularly by high concentrations of PAHs in the soils. Soil microorganisms in the PAHs contaminated soil used the added glucose to a lesser extent than in the non-contaminated soil, which in the contaminated soil resulted in a higher microbial biomass content during the first day of incubation. DDT, DDD and DDE, and PCB affected the soil microbial activities differently and, in comparison with control soils, decreased the microbial biomass C during the incubation. The increased microbial activities led to a significant decrease of PAH up to 44.6% in the soil long-term contaminated with PAHs, and up to 14% in the control soil after 12 days of incubation. No decrease of PAHs concentrations was observed in the soil which was previously amended with sewage sludges containing PAHs and had more organic matter from the sewage sludges. DDT and its derivates DDD and DDE decreased by about 10%, whereas the PCB contents were not affected at all by microbial activities. Studies on the microbial degradation of POPs could be useful for the development of methods focused on the remediation of the contaminated sites. An increase of soil microbial activities caused by addition of organic substrates can contribute to the degradation of pollutants in some soils. However, in situ biodegradation may be limited because of a complex set of environmental conditions, particularly of the soil organic matter. The degradability and availability of POPs for the soil microorganisms has to be estimated individually for each contaminated site.
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Arora, Sanjay, and Divya Sahni. "Pesticides effect on soil microbial ecology and enzyme activity- An overview." Journal of Applied and Natural Science 8, no. 2 (June 1, 2016): 1126–32. http://dx.doi.org/10.31018/jans.v8i2.929.
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In modern agriculture, chemical pesticides are frequently used in agricultural fields to increase crop production. Besides combating insect pests, these insecticides also affect the activity and population of beneficial soil microbial communities. Chemical pesticides upset the activities of soil microbes and thus may affect the nutritional quality of soils. This results in serious ecological consequences. Soil microbes had different response to different pesticides. Soil microbial biomass that plays an important role in the soil ecosystem where they have crucial role in nutrient cycling. It has been reported that field application of glyphosate increased microbial biomass carbon by 17% and microbial biomass nitrogen by 76% in nine soils at 14 days after treatment. The soil microbial biomass C increased significantly upto 30 days in chlorpyrifos as well as cartap hydrochloride treated soil, but thereafter decreased progressively with time. Soil nematodes, earthworms and protozoa are affected by field application rates of the fungicide fenpropimorph and other herbicides. Thus, there is need to assess the effect of indiscriminate use of pesticides on soil microorganisms, affecting microbial activity and soil fertility.
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Hasebe, Akira, Shinjiro Kanaza Wa, and Yasuo Takai. "Microbial Biomass in Paddy Soil." Soil Science and Plant Nutrition 31, no. 3 (September 1985): 349–59. http://dx.doi.org/10.1080/00380768.1985.10557442.
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Rosinger, Christoph, and Michael Bonkowski. "Soil age and soil organic carbon content shape biochemical responses to multiple freeze–thaw events in soils along a postmining agricultural chronosequence." Biogeochemistry 155, no. 1 (June 7, 2021): 113–25. http://dx.doi.org/10.1007/s10533-021-00816-5.
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AbstractFreeze–thaw (FT) events exert a great physiological stress on the soil microbial community and thus significantly impact soil biogeochemical processes. Studies often show ambiguous and contradicting results, because a multitude of environmental factors affect biogeochemical responses to FT. Thus, a better understanding of the factors driving and regulating microbial responses to FT events is required. Soil chronosequences allow more focused comparisons among soils with initially similar start conditions. We therefore exposed four soils with contrasting organic carbon contents and opposing soil age (i.e., years after restoration) from a postmining agricultural chronosequence to three consecutive FT events and evaluated soil biochgeoemical responses after thawing. The major microbial biomass carbon losses occurred after the first FT event, while microbial biomass N decreased more steadily with subsequent FT cycles. This led to an immediate and lasting decoupling of microbial biomass carbon:nitrogen stoichiometry. After the first FT event, basal respiration and the metabolic quotient (i.e., respiration per microbial biomass unit) were above pre-freezing values and thereafter decreased with subsequent FT cycles, demonstrating initially high dissimilatory carbon losses and less and less microbial metabolic activity with each iterative FT cycle. As a consequence, dissolved organic carbon and total dissolved nitrogen increased in soil solution after the first FT event, while a substantial part of the liberated nitrogen was likely lost through gaseous emissions. Overall, high-carbon soils were more vulnerable to microbial biomass losses than low-carbon soils. Surprisingly, soil age explained more variation in soil chemical and microbial responses than soil organic carbon content. Further studies are needed to dissect the factors associated with soil age and its influence on soil biochemical responses to FT events.
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Mühlbachová, G. "Microbial biomass dynamics after addition of EDTA into heavy metal contaminated soils." Plant, Soil and Environment 55, No. 12 (December 28, 2009): 544–50. http://dx.doi.org/10.17221/124/2009-pse.
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An incubation experiment with addition of EDTA and alfalfa into soils contaminated with heavy metal over 200 years was carried out in order to evaluate the EDTA effects on microbial properties. Alfalfa was added to soils together with EDTA to examine its abilities to improve microbial activities affected by EDTA. The obtained results showed that the addition of EDTA led to a significant decrease of microbial biomass C during the first 24 days of incubation. At the end of the experiment the microbial biomass C significantly increased quite close to the original level. The EDTA amendment caused, probably due to the toxic effects, a significant increase in respiratory activities and of the metabolic quotient <i>q</i>CO<sub>2</sub>. An addition of alfalfa significantly improved the microbial biomass C contents in arable soils treated together with EDTA. Both, respiratory activities and <i>q</i>CO<sub>2</sub> significantly increased after the soil treatment with EDTA together with alfalfa. EDTA alone decreased the microbial biomass, alfalfa alone as organic substrate was mineralised and utilised by soil microorganisms for their metabolism.
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Ma, L., C. Guo, X. Lü, S. Yuan, and R. Wang. "Soil moisture and land use are major determinants of soil microbial community composition and biomass at a regional scale in northeastern China." Biogeosciences 12, no. 8 (April 30, 2015): 2585–96. http://dx.doi.org/10.5194/bg-12-2585-2015.
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Abstract. Global environmental factors impact soil microbial communities and further affect organic matter decomposition, nutrient cycling and vegetation dynamic. However, little is known about the relative contributions of climate factors, soil properties, vegetation types, land management practices and spatial structure (which serves as a proxy for underlying effects of temperature and precipitation for spatial variation) on soil microbial community composition and biomass at large spatial scales. Here, we compared soil microbial communities using phospholipid fatty acid method across 7 land use types from 23 locations at a regional scale in northeastern China (850 × 50 km). The results showed that soil moisture and land use changes were most closely related to microbial community composition and biomass at the regional scale, while soil total C content and climate effects were weaker but still significant. Factors such as spatial structure, soil texture, nutrient availability and vegetation types were not important. Higher contributions of gram-positive bacteria were found in wetter soils, whereas higher contributions of gram-negative bacteria and fungi were observed in drier soils. The contributions of gram-negative bacteria and fungi were lower in heavily disturbed soils than historically disturbed and undisturbed soils. The lowest microbial biomass appeared in the wettest and driest soils. In conclusion, dominant climate and soil properties were not the most important drivers governing microbial community composition and biomass because of inclusion of irrigated and managed practices, and thus soil moisture and land use appear to be primary determinants of microbial community composition and biomass at the regional scale in northeastern China.
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Azlan Halmi, Muhammad, Siti Hasenan, Khanom Simarani, and Rosazlin Abdullah. "Linking Soil Microbial Properties with Plant Performance in Acidic Tropical Soil Amended with Biochar." Agronomy 8, no. 11 (November 8, 2018): 255. http://dx.doi.org/10.3390/agronomy8110255.
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Soil microbial properties are frequently used as indicators of soil fertility. However, the linkage of these properties with crop biomass is poorly documented especially in biochar amended soil with high carbon:nitrogen (C:N). A short-term field trial was conducted to observe the growth response of maize to biochar treatment in a highly weathered Ultisol of humid tropics and to observe the possible linkage of the measured microbial properties with maize biomass. Soil microbial biomass (carbon (C), nitrogen (N), phosphorus (P)), enzyme activity (β-glucosidase, urease, phosphodiesterase) and gene abundance (bacterial 16S rRNA, fungal ITS) were analyzed. For comparison, total soil C, N, and P were also analyzed. The data revealed no significant linkage of soil C, N, and P with maize biomass. A significant association of enzyme activity and gene abundance with maize biomass was not recorded. Strong positive correlation between maize above ground biomass with microbial biomass N was found (r = 0.9186, p < 0.01). Significant negative correlation was recorded between microbial biomass C:N with maize biomass (r = −0.8297, p < 0.05). These statistically significant linkages observed between microbial biomass and maize biomass suggests that microbial biomass can reflect the soil nutrient status, and possibly plant nutrient uptake. Estimation of microbial biomass can be used as a fertility indicator in soil amended with high C:N organic matter in the humid tropics.
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Wang, Huanhuan, Rui Zhang, Yuanyuan Zhao, Hongzhi Shi, and Guoshun Liu. "Effect of Biochar on Rhizosphere Soil Microbial Diversity and Metabolism in Tobacco-Growing Soil." Ecologies 3, no. 4 (November 18, 2022): 539–56. http://dx.doi.org/10.3390/ecologies3040040.
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In this study, four different biochar application rates and a control were set up using indoor potted tobacco, to study the effects of biochar on the microbial diversity and metabolism of tobacco-growing soil. The five treatments were as follows: control—0% biochar (w/w) + 26 g fertilizer/pot; biochar treatments—1% biochar (w/w) + 26 g fertilizer/pot, 2% biochar (w/w) + 26 g fertilizer/pot, 3% biochar (w/w) + 26 g fertilizer/pot, and 4% biochar (w/w) + 26 g fertilizer/pot. We found that biochar increases the microbial diversity of soils and simultaneously changes the microbial community structure. Under the influence of biochar, soil urease activity increased by 18%, invertase activity increased by 23.40%, polyphenol oxidase activity increased by 59.50%, and catalase activity increased by 30.92%. Biochar also significantly increased the microbial biomass carbon and nitrogen content of the soil. Soil microbial biomass nitrogen had a positive correlation on bacterial diversity, with the highest coefficient, while soil microbial biomass carbon had a positive correlation on fungal diversity, with the highest coefficient. The microbial diversity and metabolic capacity of soil are improved under the influence of biochar, and soil enzyme activity and microbial biomass carbon and nitrogen have positive impacts on soil microbial diversity.
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McDaniel, Marshall D., and A. Stuart Grandy. "Soil microbial biomass and function are altered by 12 years of crop rotation." SOIL 2, no. 4 (November 2, 2016): 583–99. http://dx.doi.org/10.5194/soil-2-583-2016.
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Abstract. Declines in plant diversity will likely reduce soil microbial biomass, alter microbial functions, and threaten the provisioning of soil ecosystem services. We examined whether increasing temporal plant biodiversity in agroecosystems (by rotating crops) can partially reverse these trends and enhance soil microbial biomass and function. We quantified seasonal patterns in soil microbial biomass, respiration rates, extracellular enzyme activity, and catabolic potential three times over one growing season in a 12-year crop rotation study at the W. K. Kellogg Biological Station LTER. Rotation treatments varied from one to five crops in a 3-year rotation cycle, but all soils were sampled under a corn year. We hypothesized that crop diversity would increase microbial biomass, activity, and catabolic evenness (a measure of functional diversity). Inorganic N, the stoichiometry of microbial biomass and dissolved organic C and N varied seasonally, likely reflecting fluctuations in soil resources during the growing season. Soils from biodiverse cropping systems increased microbial biomass C by 28–112 % and N by 18–58 % compared to low-diversity systems. Rotations increased potential C mineralization by as much as 53 %, and potential N mineralization by 72 %, and both were related to substantially higher hydrolase and lower oxidase enzyme activities. The catabolic potential of the soil microbial community showed no, or slightly lower, catabolic evenness in more diverse rotations. However, the catabolic potential indicated that soil microbial communities were functionally distinct, and microbes from monoculture corn preferentially used simple substrates like carboxylic acids, relative to more diverse cropping systems. By isolating plant biodiversity from differences in fertilization and tillage, our study illustrates that crop biodiversity has overarching effects on soil microbial biomass and function that last throughout the growing season. In simplified agricultural systems, relatively small increases in crop diversity can have large impacts on microbial community size and function, with cover crops appearing to facilitate the largest increases.
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Konopka, A., T. Zakharova, M. Bischoff, L. Oliver, C. Nakatsu, and R. F. Turco. "Microbial Biomass and Activity in Lead-Contaminated Soil." Applied and Environmental Microbiology 65, no. 5 (May 1, 1999): 2256–59. http://dx.doi.org/10.1128/aem.65.5.2256-2259.1999.
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ABSTRACT Microbial community diversity, potential microbial activity, and metal resistance were determined in three soils whose lead contents ranged from 0.00039 to 48 mmol of Pb kg of soil−1. Biomass levels were directly related to lead content. A molecular analysis of 16S rRNAs suggested that each soil contained a complex, diverse microbial community. A statistical analysis of the phospholipid fatty acids indicated that the community in the soil having the highest lead content was not related to the communities in the other soils. All of the soils contained active microbial populations that mineralized [14C]glucose. In all samples, 10 to 15% of the total culturable bacteria were Pb resistant and had MIC of Pb for growth of 100 to 150 μM.
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King, Andrew J., Debendra Karki, Laszlo Nagy, Adina Racoviteanu, and Steve K. Schmidt. "Microbial biomass and activity in high elevation (>5100 meters) soils from the Annapurna and Sagarmatha regions of the Nepalese Himalayas." Himalayan Journal of Sciences 6, no. 8 (June 28, 2011): 11–18. http://dx.doi.org/10.3126/hjs.v6i8.2303.
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High elevation subnival-zone soils are increasing in spatial extent in the Himalayas due to glacial retreat and grazing pressures. These seemingly barren soils actually harbor significant microbial diversity but have remained mostly unstudied in all of the major mountain ranges of the Earth. Here we describe a preliminary survey of subnival-zone soils and one vegetated high-elevation soil in the Annapurna and Sagarmatha regions of the Nepalese Himalayas. We examined microbial biomass and activity as well as key microclimatic and edaphic variables that may control microbial activity in these soils. Microbial biomass carbon levels were the lowest ever reported for any soil to date, whereas microbial nitrogen and soil enzyme activities were similar to levels measured in previous studies of subnival-zone soils of Peru and Colorado. Our initial studies also indicate that soil water availability is the primary limiting factor for life in these high-elevation soils. Key words: Microbial; soil; biogeochemistry; subnival; extracellular enzymes; microbial biomass DOI: http://dx.doi.org/10.3126/hjs.v6i8.2303 Himalayan Journal of Sciences Vol.6 Issue 8 2010 pp.11-18
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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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Spohn, M. "Microbial respiration per unit microbial biomass depends on soil litter carbon-to-nitrogen ratio." Biogeosciences Discussions 11, no. 10 (October 24, 2014): 15037–51. http://dx.doi.org/10.5194/bgd-11-15037-2014.
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Abstract. Soil microbial respiration is a central process in the terrestrial carbon (C) cycle. In this study I tested the effect of the carbon-to-nitrogen (C : N) ratio of soil litter layers on microbial respiration in absolute terms and per unit microbial biomass C. For this purpose, a global dataset on microbial respiration per unit microbial biomass C – termed the metabolic quotient (qCO2) – was compiled form literature data. It was found that the qCO2 in the soil litter layers was positively correlated with the litter C : N ratio and negatively related with the litter nitrogen (N) concentration. The positive relation between qCO2 and litter C : N ratio resulted from an increase in respiration with the C : N ratio in combination with no significant effect of the litter C : N ratio on the soil microbial biomass C concentration. The results suggest that soil microorganisms respire more C both in absolute terms and per unit microbial biomass C when decomposing N-poor substrate. Thus, the findings indicate that atmospheric N deposition, leading to decreased litter C : N ratios, might decrease microbial respiration in soils.
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Ma, L., C. Guo, X. Lü, S. Yuan, and R. Wang. "Do climate factors govern soil microbial community composition and biomass at a regional scale?" Biogeosciences Discussions 11, no. 12 (December 18, 2014): 17729–56. http://dx.doi.org/10.5194/bgd-11-17729-2014.
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Abstract. Soil microbial communities play important role in organic matter decomposition, nutrient cycling and vegetation dynamic. However, little is known about factors driving soil microbial community composition at large scales. The objective of this study was to determine whether climate dominates among environmental factors governing microbial community composition and biomass at a regional scale. Here, we compared soil microbial communities using phospholipid fatty acid method across 7 land use types from 23 locations in North-East China Transect (850 km x 50 km). The results showed that soil water availability and land use changes exhibited the dominant effects on soil microbial community composition and biomass at the regional scale, while climate factors (expressed as a function of large-scale spatial variation) did not show strong relationships with distribution of microbial community composition. Likewise, factors such as spatial structure, soil texture, nutrient availability and vegetation types were not important. Wetter soils had higher contributions of gram-positive bacteria, whereas drier soils had higher contributions of gram-negative bacteria and fungi. Heavily disturbed soils had lower contributions of gram-negative bacteria and fungi than historically disturbed and undisturbed soils. The lowest microbial biomass appeared in the wettest and driest soils. In conclusion, dominant climate factors, commonly known to structure distribution of macroorganisms, were not the most important drivers governing regional pattern of microbial communities because of inclusion of irrigated and managed practices. In comparison, soil water regime and land use types appear to be primary determinants of microbial community composition and biomass.
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Mühlbachová, G., and T. Šimon. "Effects of zeolite amendment on microbial biomass and respiratory activity in heavy metal contaminated soils." Plant, Soil and Environment 49, No. 12 (December 11, 2011): 536–41. http://dx.doi.org/10.17221/4190-pse.
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A laboratory incubation experiment with zeolite and glucose was performed to evaluate the effects of zeolite amendment in heavy metal contaminated soils from two smelter areas on some microbial characteristics [Kremikovtzi (K1, K2) in Bulgariaand Příbram (P1, P2) in the CzechRepublic]. The content of microbial biomass showed a tendency to decrease in Kremikovtzi soils whereas in Příbram soils no significant effects were found after zeolite amendment. Respiratory activity and metabolic quotient (qCO2) decreased on the second and third day in Kremikovtzi soils amended with zeolite, no effects were observed in Příbram soils. Heavy metals decreased the content of microbial biomass in Kremikovtzi soils whereas the contaminated soil from Příbram area had the highest microbial biomass compared to non-contaminated soil during incubation, probably due to lower mineralization of carbon. The respiratory activity did not show any significant effects of zeolites on the evolution of CO2 and qCO2 in heavy metal contaminated Příbram soil. The respiratory activity in non-contaminated Příbram soil remained during the experiment lower in comparison to contaminated one, however the addition of zeolite increased qCO2.
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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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Mele, P. M., and M. R. Carter. "SHORT COMMUNICATION: Estimation of microbial biomass by ninhydrin-reactive N using liquid chloroform." Canadian Journal of Soil Science 76, no. 1 (February 1, 1996): 37–40. http://dx.doi.org/10.4141/cjss96-006.
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Ninhydrin-reactive N (NRN), which is a reliable and sensitive indicator of soil microbial biomass, was measured in extracts of three Australian duplex soils, under different tillage systems, fumigated using either vaporized or liquid CHCl3. Although the relationship between the two fumigation-extraction methods was influenced by soil type, the use of liquid CHCl3 appears to be a promising technique to allow greater ease and speed for releasing NRN in microbial biomass analysis. Key words: Duplex soils, tillage, microbial biomass, fumigation-extraction method
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Zhao, Xing, Xingliang Xu, Fang Wang, Isabel Greenberg, Min Liu, Rongxiao Che, Li Zhang, and Xiaoyong Cui. "Climatic, Edaphic and Biotic Controls over Soil δ13C and δ15N in Temperate Grasslands." Forests 11, no. 4 (April 10, 2020): 433. http://dx.doi.org/10.3390/f11040433.
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Soils δ13C and δ15N are now regarded as useful indicators of nitrogen (N) status and dynamics of soil organic carbon (SOC). Numerous studies have explored the effects of various factors on soils δ13C and δ15N in terrestrial ecosystems on different scales, but it remains unclear how co-varying climatic, edaphic and biotic factors independently contribute to the variation in soil δ13C and δ15N in temperate grasslands on a large scale. To answer the above question, a large-scale soil collection was carried out along a vegetation transect across the temperate grasslands of Inner Mongolia. We found that mean annual precipitation (MAP) and mean annual temperature (MAT) do not correlate with soil δ15N along the transect, while soil δ13C linearly decreased with MAP and MAT. Soil δ15N logarithmically increased with concentrations of SOC, total N and total P. By comparison, soil δ13C linearly decreased with SOC, total N and total P. Soil δ15N logarithmically increased with microbial biomass C and microbial biomass N, while soil δ13C linearly decreased with microbial biomass C and microbial biomass N. Plant belowground biomass linearly increased with soil δ15N but decreased with soil δ13C. Soil δ15N decreased with soil δ13C along the transect. Multiple linear regressions showed that biotic and edaphic factors such as microbial biomass C and total N exert more effect on soil δ15N, whereas climatic and edaphic factors such as MAT and total P have more impact on soil δ13C. These findings show that soil C and N cycles in temperate grasslands are, to some extent, decoupled and dominantly controlled by different factors. Further investigations should focus on those ecological processes leading to decoupling of C and N cycles in temperate grassland soils.
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Harris, D., R. P. Voroney, and E. A. Paul. "Measurement of microbial biomass N:C by chloroform fumigation-incubation." Canadian Journal of Soil Science 77, no. 4 (November 1, 1997): 507–14. http://dx.doi.org/10.4141/s96-064.
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We present a calculation for soil microbial biomass N:C ratio determined from a 10-d incubation following chloroform fumigation. The calculation is based on a mathematical model of the N content of the pre- and post-fumigation soil microbial biomass and the growth yield of the biomass that develops after fumigation. Biomass N is calculated from the N:C ratio and biomass C. The mineralization of bacteria and fungi, with different N contents, added to fumigated soils was used to establish the model parameters. The model was tested against an independent set of measurements and considers two assumptions: 1) The ratio of N:C mineralized from killed biomass is equal to the ratio of N:C mineralized from soil non-biomass constituents. 2) More realistically, the N and C mineralization in the fumigated soil, from sources other than killed biomass, is a residual fraction of the N and C mineralization in the unfumigated soil. Biomass C:N ratios calculated without a control correction (assumption 1) were, on average, 20% wider than corrected values (assumption 2). Biomass N calculated as the product of N:C and biomass C was compared with published values for several data sets. The new calculation method was robust even when net immobilization of N followed fumigation. Key words: Soil microbial biomass, nitrogen, chloroform fumigation, C:N ratio
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Amaral, F., and M. Abelho. "Effects of agricultural practices on soil and microbial biomass carbon, nitrogen and phosphorus content: a preliminary case study." Web Ecology 16, no. 1 (January 18, 2016): 3–5. http://dx.doi.org/10.5194/we-16-3-2016.
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Abstract. In this study we assessed the C : N : P ratios in soil and soil microbial biomass subject to conventional farming and three different organic farming practices. The results showed that microbial biomass was P-limited in soils subject to conventional farming and to organic farming with alfalfa green manure. Organic farming with compost amendment showed the best results in terms of microbial biomass carbon, nitrogen and phosphorus (CNP).
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Singh, Mahesh Kumar, and Nandita Ghoshal. "Variation in soil microbial biomass in the dry tropics: impact of land-use change." Soil Research 52, no. 3 (2014): 299. http://dx.doi.org/10.1071/sr13265.
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The impact of land-use change on soil microbial biomass carbon (C) and nitrogen (N) was studied through two annual cycles involving natural forest, degraded forest, agroecosystem and Jatropha curcas plantation. Soil microbial biomass C and N, soil moisture content and soil temperature were analysed at upper (0–10 cm), middle (10–20 cm) and lower (20–30 cm) soil depths during the rainy, winter and summer seasons. The levels of microbial biomass C and N were highest in the natural forest, followed in decreasing order by Jatropha curcas plantation, degraded forest and the agroecosystem. The highest level of soil microbial biomass C and N was observed during summer, decreasing through winter to the minimum during the rainy season. Soil microbial biomass C and N decreased with increasing soil depth for all land-use types, and for all seasons. Seasonal variation in soil microbial biomass was better correlated with the soil moisture content than with soil temperature. The microbial biomass C/N ratio increased with the soil depth for all land-use types, indicating changes in the microbial community with soil depth. It is concluded that the change in land-use pattern, from natural forest to other ecosystems, results in a considerable decrease in soil microbial biomass C and N. Jatropha plantation may be an alternative for the restoration of degraded lands in the dry tropics.
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Zhai, Silong, Chaofan Xu, Yongcheng Wu, Jian Liu, Yali Meng, and Haishui Yang. "Long-term ditch-buried straw return alters soil carbon sequestration, nitrogen availability and grain production in a rice–wheat rotation system." Crop and Pasture Science 72, no. 4 (2021): 245. http://dx.doi.org/10.1071/cp20444.
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Our previous studies indicated that ditch-buried straw return (DB-SR) can improve soil processes in the short term, i.e. increasing microbial metabolic capability, reducing nitrogen leaching loss and promoting soil aggregation. However, it remains unclear how long-term implementation of DB-SR affects soil carbon (C) and nitrogen (N) processes and crop yields. Here, the effects of DB-SR on soil C pool and N availability as well as grain yields were investigated after consecutive application of 6 (rice season) and 6.5 years (wheat season). We found that long-term DB-SR significantly increased rice yields, total organic C, NH4+ and NO3– in the rice soils, as well as enhanced wheat yields, microbial biomass C, microbial biomass N, microbial biomass C/total organic C ratio and microbial biomass C/N ratio, but reduced NH4+ and NO3– in the wheat soils when compared with rotary tillage straw return (RT-SR) and no tillage with straw removal (NT-NS). These findings suggest that long-term DB-SR application has positive effects on grain production, but possibly through different mechanisms in improving soil processes. The yield-increasing effects on rice might result from improvements in soil fertility, whereas increased wheat yields can be ascribed to stimulated soil microbial activity.
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Gömöryová, Erika, Gabriela Barančíková, Erika Tobiašová, Ján Halás, Rastislav Skalský, Štefan Koco, and Dušan Gömöry. "Responses of soil microorganisms to land use in different soil types along the soil profiles." Soil and Water Research 15, No. 2 (March 11, 2020): 125–34. http://dx.doi.org/10.17221/20/2019-swr.
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The objective of this study was to find out how land use affects the soil microbial attributes in different soil types and to which depth. The study was performed in Slovakia (Europe) in three areas differing in soil type (Chernozem, Stagnosol, Cambisol). Within each area, three localities with different land use (forest, grassland, cropland), representing a gradient with different intensity of management, were chosen. The soil samples were taken along a single soil profile up to a depth of 1 m with 10 cm increments at each locality. In the soil samples, the basic soil chemical properties and microbial attributes were determined. The effect of the land use on the microbial biomass and basal respiration was mainly observed in the Chernozem in the top 30 cm, while in the Stagnosol, no difference in the trend in the microbial biomass between the different ecosystems along the soil profile was found. The N-mineralisation reflected the different management practices especially in the Cambisol in the top 20 cm. The most distinct differences in the catalase activity between the soils differing in land use were found in the Cambisol along the whole profile. The richness and diversity of the functional groups did not differ significantly between the soils with the different land use and also no uniform responses of the functional groups composition to the land use were observed. The microbial biomass and activity were mainly affected by the amount of the soil organic matter; the intensity of the impact differed according to the soil type.
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Liu, Yanmei, Hangyu Yang, Zisheng Xing, Yali Zou, and Zheming Cui. "Vegetation Degradation of Guanshan Grassland Suppresses the Microbial Biomass and Activity of Soil." Land 10, no. 2 (February 17, 2021): 203. http://dx.doi.org/10.3390/land10020203.
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Changes in vegetation influence the function of grassland ecosystems. A degradation of the vegetation type has been found from high to low altitudes in Guanshan grassland in the order of forest grassland (FG) < shrub grassland (SG) < herb grassland (HG). However, there is poor information regarding the effect of vegetation degradation on soil microbes in Guanshan grassland. Therefore, our study evaluated the impact of vegetation degradation on the microbial parameters of soil, as well as the mechanisms responsible for these variations. Soils were sampled from 0 to 30 cm under the FG, SG, and HG in Guanshan grassland for determining the microbial biomass, enzymatic activities, basal respiration (BR), and metabolic quotient (qCO2) in April and July 2017. The results showed that vegetation types are important factors that obviously influence the above-mentioned soil microbial properties. The FG and SG had significantly higher soil microbial biomass, enzymatic activities, and BR than those of the HG, but markedly lower qCO2 (p < 0.05). Soil pH, available nitrogen (AN), organic carbon (SOC), total phosphorus (TP), available P (AP), and total N (TN) were key factors in the decline in the soil microbial biomass and microbial activities of the degraded vegetation. Moreover, slope aspects also affected the soil microbial properties, with the east slope having higher soil microbial biomass, enzymatic activities, and BR and lower qCO2 than the west slope. Conclusively, vegetation degradation has led to a decline in the soil microbial biomass and microbial activities, indicating the degradation of the Guanshan grassland ecosystem.
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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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Anders, Elena, Andrea Watzinger, Franziska Rempt, Barbara Kitzler, Bernhard Wimmer, Franz Zehetner, Karl Stahr, Sophie Zechmeister-Boltenstern, and Gerhard Soja. "Biochar affects the structure rather than the total biomass of microbial communities in temperate soils." Agricultural and Food Science 22, no. 4 (December 18, 2013): 404–23. http://dx.doi.org/10.23986/afsci.8095.
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Biochar application is a promising strategy for sequestering carbon in agricultural soils and for improving degraded soils. Nonetheless, contradictory and unsettled issues remain. This study investigates whether biochar influences the soil microbial biomass and community structure using phospholipid fatty acid (PLFA) analysis. We monitored the effects of four different types of biochar on the soil microbial communities in three temperate soils of Austria over several months. A greenhouse experiment and two field experiments were conducted. The biochar application did not significantly increase or decrease the microbial biomass. Only the addition of vineyard pruning biochar pyrolysed at 400°C caused microbial biomass to increase in the greenhouse experiment. The biochar treatments however caused shifts in microbial communities (visualized by principal component analysis). We concluded that the shifts in the microbial community structure are an indirect rather than a direct effect and depend on soil conditions and nutrient status.
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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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Wiseman, P. Eric, Susan Day, and J. Roger Harris. "Organic Amendment Effects on Soil Carbon and Microbial Biomass in the Root Zone of Three Landscape Tree Species." Arboriculture & Urban Forestry 38, no. 6 (November 1, 2012): 262–76. http://dx.doi.org/10.48044/jauf.2012.036.
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There is increasing interest in amending degraded soils with organic matter to improve soil quality, especially in urban areas where rehabilitation of damaged soils may enhance tree growth and provision of ecosystem services. To assess the potential of such organic amendments for producing a sustained alteration in soil biological characteristics, researchers studied the effects of three organic amendments incorporated into the root zone of three tree species on root development, soil carbon dynamics, and soil microbial biomass over one year beginning 20 months after amendment application. Soil amendment with leaf-based, and to a lesser extent, biosolids-based composts increased root length within the amended root zone of red maple (Acer rubrum), but not of pin oak (Quercus palustris) or chestnut oak (Q. montana). There was a concomitant increase in microbial biomass carbon for red maple. Across all species, sphagnum peat moss amendment reduced microbial biomass carbon by 47% compared to unamended root zones and suppressed maximum seasonal soil respiration relative to composts. In contrast, leaf-based compost increased microbial biomass carbon by 12% (P = 0.0989) compared to unamended root zones. Carbon/nitrogen ratios remained stable throughout most of the year except in the root zones of chestnut oak and pin oak amended with peat, where it declined 44%–85%. Total soil carbon was stable in all treatments, although unamended soils averaged about 40% lower than amended soils. Across all species and treatments, cumulative fine root length explained 19% of the variation in microbial biomass carbon. The study authors conclude that soil microbial activity can be increased by compost amendment of the root zone and that this increase is mediated to some degree by tree roots. In addition, stable C/N ratios suggest this alteration in the root zone may be sustainable. Further research may clarify whether compost amendment combined with tree planting can accelerate soil restoration.
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Lupwayi, N. Z., W. A. Rice, and G. W. Clayton. "Soil microbial biomass and carbon dioxide flux under wheat as influenced by tillage and crop rotation." Canadian Journal of Soil Science 79, no. 2 (May 1, 1999): 273–80. http://dx.doi.org/10.4141/s98-052.
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Soil organic matter is important both from an agronomic and an environmental perspective because it affects the capacity of the soil to sustain crop growth, and it is a source and sink of atmospheric CO2-C. Soil microbial biomass comprises a small proportion of total soil organic matter, but it is more dynamic than total soil organic matter. Therefore, measurements of soil microbial biomass may show the effects of soil management on potential changes in soil organic matter before such effects can be detected by measuring total soil organic matter. The effects of tillage and crop rotation on soil microbial biomass and activity were studied in 1995–1997 in the wheat phase of different cropping rotations that had been established in 1992 under zero tillage or conventional tillage in northern Alberta. Soil microbial biomass was often significantly (P < 0.05) higher, but never significantly lower, under zero tillage than under conventional tillage. However, CO2 evolution (basal respiration) was usually higher under conventional tillage than under zero tillage, resulting in higher specific respiration (qCO2) under conventional tillage than under zero tillage. The higher additions but lower losses of labile C under zero tillage mean that more C is sequestered in the soil in the zero-tillage system. Thus, this system contributes less to atmospheric CO2 than conventional tillage, and that soil organic matter accumulates more under zero tillage. Plots preceded by summerfallow, especially under conventional tillage, usually had the lowest microbial biomass and CO2 evolution, and plots preceded by legume crops had higher microbial biomass and lower qCO2 than other treatments. Tillage and rotation had little effect on total soil organic matter 5 yr after the treatments had been imposed, probably because of the cold climate of northern Alberta, but the results confirm that the labile forms of soil C are more sensitive indicators of soil organic C trends than total soil organic C. These effects of tillage and rotation on soil microbial biomass were similar to those on microbial diversity reported previously. These results confirm that zero tillage and legume-based crop rotations are more sustainable crop management systems than conventional tillage and fallowing in the Gray Luvisolic soils of northern Alberta. Key words: Carbon sequestration, carbon mineralization, microbial activity, soil organic matter
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Hulm, S. C., D. L. Castle, K. Cook, A. Self, and M. Wood. "Evaluation of soil microbial biomass methodology." Toxicological & Environmental Chemistry 30, no. 3-4 (June 1991): 183–92. http://dx.doi.org/10.1080/02772249109357654.
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TATE, ROBERT L. "MICROBIAL BIOMASS MEASUREMENT IN ACIDIC SOIL." Soil Science 152, no. 3 (September 1991): 220–25. http://dx.doi.org/10.1097/00010694-199109000-00009.
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Jiang-shan, Zhang, Guo Jian-fen, Chen Guang-shui, and Qian Wei. "Soil microbial biomass and its controls." Journal of Forestry Research 16, no. 4 (December 2005): 327–30. http://dx.doi.org/10.1007/bf02858201.
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Song, Qianqian, Yifan He, Yuefeng Wu, Shipin Chen, Taoxiang Zhang, and Hui Chen. "Biochar Impacts on Acidic Soil from Camellia Oleifera Plantation: A Short-Term Soil Incubation Study." Agronomy 10, no. 9 (September 22, 2020): 1446. http://dx.doi.org/10.3390/agronomy10091446.
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Nowadays, biochar is increasingly used widely as an important soil amendment to enhance soil nutrients availability. Therefore, we investigated the effect of C.oleifera shell biochar (CSB) on C.oleifera plantation soils to provide evidence that C. oleifera shell as a raw material in biochar has great potential to be a soil amendment. For this, a short-term incubation experiment was conducted in controlled conditions to evaluate the effects of CSB application on two soil chemical properties, microbial biomass, and enzymatic activity. We compared two acidic soils, mixed with CSB of three pyrolysis temperatures (300, 500, and 700 °C), and two application rates (3% and 5% (w/w)), incubated for 180 days. The results showed that the soil pH, total P (TP), and available P (AP) significantly increased under 5CSB700 in two soils, and indicated CSB application rate and pyrolysis temperature had a significant impact on soil pH, TP, and AP (p < 0.05). CSB application also significantly increased the total inorganic P in two soils and presented a significantly positive correlation with soil pH, TP, and AP under redundancy analysis. The results suggested that CSB application has a variable effect on soil enzymatic activity, microbial biomass C (MBC), and microbial biomass P (MBP) on average, while it increased the soil microbial biomass N (MBN) in both soils. We concluded that CSB could be a soil amendment to increase soil nutrients of C.oleifera plantation soils. Before the application of biochar to C.oleifera plantation forest soils, long-term studies are required to assess the effects of biochar under field conditions and its promoting effect on the growth of C. oleifera.
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Yoshitake, Shinpei, and Takayuki Nakatsubo. "Changes in soil microbial biomass and community composition along vegetation zonation in a coastal sand dune." Soil Research 46, no. 4 (2008): 390. http://dx.doi.org/10.1071/sr07104.
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We used phospholipid fatty acid (PLFA) analysis to examine the relation of microbial biomass and community composition to vegetation zonation on a coastal sand dune. Soil samples were collected along 3 line transects established from the shoreline to the inland bush. Total PLFA content and PLFA composition of soils were used as indices of total microbial biomass and community composition, respectively. The microbial biomass was much higher in the inland Vitex rotundifolia zone than in the seaside plots. The microbial community composition also differed among the vegetation zones, with a higher contribution of fungal biomarkers in the inland plots. The microbial biomass increased significantly with increasing soil organic matter (SOM) content, but was not correlated with soil salinity. These results suggest that microbial biomass in the coastal sand dune was controlled primarily by the accumulation of SOM. The microbial community composition also changed with SOM content in the seaside plots, but SOM had little effect in the inland plots. These results suggest that the factors limiting the microbial community composition differed with location on the dune.
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Heinze, Stefanie, Michael Hemkemeyer, Sanja Annabell Schwalb, Khalid Saifullah Khan, Rainer Georg Joergensen, and Florian Wichern. "Microbial Biomass Sulphur—An Important Yet Understudied Pool in Soil." Agronomy 11, no. 8 (August 12, 2021): 1606. http://dx.doi.org/10.3390/agronomy11081606.
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Soil microorganisms require a range of essential elements for their optimal functioning and store several elements in the microbial biomass (MB), such as carbon (C), nitrogen (N), phosphorus (P) and sulphur (S), as well as other secondary and trace elements. The C, N and P content of the microbial biomass has been quantified in many studies for many years, whereas S has been the focus only in a few studies, despite the availability of methods and the relevance of MBS for the S turnover in soils. To illustrate the relevance of MBS, this review aims at summarizing the current state of knowledge on the quantities of MBS in different soils, influencing environmental and agricultural management factors, methodological shortcomings, and prospects for soil microbial biomass research. Median MBS contents were 6.0 µg g−1 soil in arable, 7.6 µg g−1 soil in grassland, and 5.7 µg g−1 soil in forest soils. All extractants used led to similar MBS contents in soils with similar soil organic (SO) C contents. MBC and soil pH positively explained MBS, using multiple linear regression analysis. Median MB-C/S ratios increased in the order arable (55), grassland (85), and forest (135) soils. As the overall quantity of MBS data is still small, future studies are required to verify these observations. Moreover, future research needs to more strongly consider stoichiometric relationships of elements in the soil and the soil microbial ionome. The role of S and its complex relationship with the availability of other elements in soils for the soil microbial biomass and its functions remains to be elucidated.
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Xu, Chao, Teng-Chiu Lin, Jr-Chuan Huang, Zhijie Yang, Xiaofei Liu, Decheng Xiong, Shidong Chen, Minhuang Wang, Liuming Yang, and Yusheng Yang. "Microbial Biomass Is More Important than Runoff Export in Predicting Soil Inorganic Nitrogen Concentrations Following Forest Conversion in Subtropical China." Land 11, no. 2 (February 15, 2022): 295. http://dx.doi.org/10.3390/land11020295.
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Elevated runoff export and declines in soil microbial biomass and enzyme activity following forest conversion are known to reduce soil inorganic nitrogen (N) but their relative importance remains poorly understood. To explore their relative importance, we examined soil inorganic N (NH4+ and NO3−) concentrations in relation to microbial biomass, enzyme activity, and runoff export of inorganic N in a mature secondary forest, young (five years old) Castanopsis carlessi and Cunninghamia lanceolate (Chinese fir) plantations, and forests developing through assisted natural regeneration (ANR). The surface runoff export of inorganic N was greater, but fine root biomass, soil microbial biomass, enzyme activity, and inorganic N concentrations were smaller in the young plantations than the secondary forest and the young ANR forests. Microbial biomass, enzyme activity, and runoff inorganic N export explained 84% and 82% of the variation of soil NH4+ and NO3− concentrations, respectively. Soil microbial biomass contributed 61% and 94% of the explaining power for the variation of soil NH4+ and NO3− concentrations, respectively, among the forests. Positive relationships between microbial enzyme activity and soil inorganic N concentrations were likely mediated via microbial biomass as it was highly correlated with microbial enzyme activity. Although surface runoff export can reduce soil inorganic N, the effect attenuated a few years after forest conversion. By contrast, the differences in microbial biomass persisted for a long time, leading to its dominance in regulating soil inorganic N concentrations. Our results highlight that most of the variation in soil inorganic N concentration following forest conversion was related to soil microbial biomass and that assisted natural regeneration can effectively conserve soil N.
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Saggar, S., C. B. Hedley, and G. J. Salt. "Soil microbial biomass, metabolic quotient, and carbon and nitrogen mineralisation in 25-year-old Pinus radiata agroforestry regimes." Soil Research 39, no. 3 (2001): 491. http://dx.doi.org/10.1071/sr00012.
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To understand the effects of agroforestry on soil biological processes we assessed the conditions in Pinus radiata plantations of 50, 100, 200, and 400 stems/ha after 25 years of growth, and in a grassland. Agroforestry resulted in a 15–25% decline in soil organic C and N compared with grassland, and had a significant negative influence on soil microbial biomass. There was less microbial C and N in soils under 50–400 stems/ha of P. radiata than in soils under grassland (0 stems/ha). Soil carbon decomposition and microbial activity were measured by trapping the carbon dioxide produced by incubating soils over a 60-week period. The results showed that soil C decomposition rates were ~1.5 times as much (c. 15 mg CO2-C/kg soil) in soil from grassland as in that from plots with 50 or100 stems/ha (c. 10 mg CO2-C/kg soil), and were further reduced to one half (c. 5.5 mg CO2-C/kg soil) in the plots with 200 or 400 stems/ha. The soils under P. radiata gave off less carbon dioxide per unit of biomass (the metabolic quotient) than soils under grassland. These shifts in microbial biomass and its metabolic quotients appear to be associated with differences in the quantity and ‘quality’ of inputs and soil organic matter decomposition rates, and to reflect the land use change from grassland to forest. Given the general ability of soil microbial biomass to recolonise depopulated areas after tree harvest, we see no problem in restoring populations of these soil organisms vital in controlling nutrient cycling after tree felling, provided adequate adjustments to soil pH are made.
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Zhang, Yao, Junqi Wang, Lan Chen, Sha Zhou, Lu Zhang, and Fazhu Zhao. "Different Response of Soil Microbial Carbon Use Efficiency in Compound of Feldspathic Sandstone and Sand." Agriculture 13, no. 1 (December 24, 2022): 58. http://dx.doi.org/10.3390/agriculture13010058.
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The stoichiometry of efficient soil microbial carbon use is a sensitive index for measuring changes in soil quality and plays a crucial role in research on ecological stoichiometry in the soil nutrient cycle. To further understand the effect of feldspathic sandstone and sand compound ratios on microbial carbon use efficiency (CUE), we simulated the field conditions of the feldspathic sandstone-sand compound layer in the Mu Us sandy land and analyzed the soil C:N:P ratio, microbial biomass, extracellular enzyme activity, and microbial carbon use efficiency in soils with different compound ratios. The results demonstrated that an increase in the feldspathic sandstone content had insignificant effects on the soil C:N:P ratio. The maximum values for microbial biomass nitrogen (MBN) and microbial biomass phosphorus (MBP) were observed at compound ratios of 1:5 and 1:2, respectively. Calculations of microbial carbon use efficiency and vector analysis revealed that the microbial carbon use efficiency increased as the feldspathic sandstone content increased, P limitation existed in all compound soils, and soil with a 1:1 compound ratio may be substantially less limited. In conclusion, our research indicated that adding feldspathic sandstone to sand improved soil quality, and the compound ratio affected soil microorganisms; nevertheless, it did not significantly change soil nutrient restriction. Our study provides a theoretical basis for the development and utilization of desert land resources.
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Santric, Ljiljana, Ljiljana Radivojevic, Gajic Umiljendic, Rada Djurovic-Pejcev, and Marija Saric-Krsmanovic. "Assessment of microbial activity and biomass in different soils exposed to nicosulfuron." Pesticidi i fitomedicina 29, no. 3 (2014): 213–19. http://dx.doi.org/10.2298/pif1403213s.
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The effects of the herbicide nicosulfuron on the abundance of cellulolytic and proteolytic microorganisms, activity of ?-glucosidase and protease enzymes, and microbial phosphorus biomass were examined. A laboratory bioassay was set up on two types of agricultural soils differing in physicochemical properties. The following concentrations were tested: 0.3, 0.6, 3.0 and 30.0 mg a.i./kg of soil. Samples were collected 3, 7, 14, 30 and 45 days after treatment with nicosulfuron. The results showed that nicosulfuron significantly reduced the abundance of cellulolytic microorganisms in both soils, as well as microbial biomass phosphorus in sandy loam soil. The herbicide was found to stimulate ?-glucosidase and protease activity in both types of soil and microbial biomass phosphorus in loamy soil. Proteolytic microorganisms remained unaffected by nicosulfuron.
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Shi, W., J. Becker, M. Bischoff, R. F. Turco, and A. E. Konopka. "Association of Microbial Community Composition and Activity with Lead, Chromium, and Hydrocarbon Contamination." Applied and Environmental Microbiology 68, no. 8 (August 2002): 3859–66. http://dx.doi.org/10.1128/aem.68.8.3859-3866.2002.
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ABSTRACT Microbial community composition and activity were characterized in soil contaminated with lead (Pb), chromium (Cr), and hydrocarbons. Contaminant levels were very heterogeneous and ranged from 50 to 16,700 mg of total petroleum hydrocarbons (TPH) kg of soil−1, 3 to 3,300 mg of total Cr kg of soil−1, and 1 to 17,100 mg of Pb kg of soil−1. Microbial community compositions were estimated from the patterns of phospholipid fatty acids (PLFA); these were considerably different among the 14 soil samples. Statistical analyses suggested that the variation in PLFA was more correlated with soil hydrocarbons than with the levels of Cr and Pb. The metal sensitivity of the microbial community was determined by extracting bacteria from soil and measuring [3H]leucine incorporation as a function of metal concentration. Six soil samples collected in the spring of 1999 had IC50 values (the heavy metal concentrations giving 50% reduction of microbial activity) of approximately 2.5 mM for CrO4 2− and 0.01 mM for Pb2+. Much higher levels of Pb were required to inhibit [14C]glucose mineralization directly in soils. In microcosm experiments with these samples, microbial biomass and the ratio of microbial biomass to soil organic C were not correlated with the concentrations of hydrocarbons and heavy metals. However, microbial C respiration in samples with a higher level of hydrocarbons differed from the other soils no matter whether complex organic C (alfalfa) was added or not. The ratios of microbial C respiration to microbial biomass differed significantly among the soil samples (P < 0.05) and were relatively high in soils contaminated with hydrocarbons or heavy metals. Our results suggest that the soil microbial community was predominantly affected by hydrocarbons.
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Barin, Mohsen, Nasser Aliasgharzad, Pål Axel Olsson, and MirHassan Rasouli-Sadaghiani. "Salinity-induced differences in soil microbial communities around the hypersaline Lake Urmia." Soil Research 53, no. 5 (2015): 494. http://dx.doi.org/10.1071/sr14090.
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Lake Urmia in north-western Iran is one of the largest hypersaline lakes in the world, and agricultural production in the surrounding area is limited by soil salinity. We investigated the effects of salinity on belowground microbial communities in soils collected from fields of cultivated onions (Allium cepa L.) and lucerne (Medicago sativa L.), and sites with the native halophyte samphire (Salicornia europaea L.). We tested the hypotheses that salinity reduces microbial biomass and changes the structure of the microbial community. The physical and chemical properties of soil samples were analysed, and phospholipid fatty acids were identified as signatures for various microbial groups. We found that the organic carbon (OC) content was the dominant determinant of microbial biomass. We also found linear relationships between OC and the biomass of various groups of organisms across the wide salinity gradient studied. Salinity, on the other hand, caused changes in the microbial fatty acid composition that indicated adaptation to stress and favoured saprotrophic fungi over bacteria, and Gram-negative bacteria over Gram-positive. Principal component analysis showed that salinity variables and microbial stress indices formed one group, and OC and microbial biomass another. The importance of OC for high microbial biomass in severely stressed soils indicates that OC amendment may be used to mitigate salt stress and as a method of managing saline soils.
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Manral, Vijyeta, Kiran Bargali, Surendra Singh Bargali, Himani Karki, and Ravi Kant Chaturvedi. "Seasonal Dynamics of Soil Microbial Biomass C, N and P along an Altitudinal Gradient in Central Himalaya, India." Sustainability 15, no. 2 (January 14, 2023): 1651. http://dx.doi.org/10.3390/su15021651.
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This study was conducted in a temperate mixed oak–pine forest of Central Himalaya, India to (i) evaluate altitudinal and seasonal variations in the microbial biomass carbon (C), nitrogen (N) and phosphorus (P) and (ii) analyse the relationships between soil microbial biomass C, N and P and physico-chemical properties of soil. Three permanent plots were established in natural forest stands along an altitudinal gradient, three replicates were collected seasonally from each site, and microbial biomass (C, N and P) were determined by a fumigation extraction method. Microbial biomass C, N and P decreased significantly (p < 0.01, correlation coefficient 0.985, 0.963, 0.948, respectively) with increasing altitude having maximum values during rainy season and minimum values during winter season. Microbial biomass C, N and P showed positive correlations with silt particles, water holding capacity, bulk density, soil moisture, organic C, total N and P and negative correlations with sand particles, porosity and soil pH. Microbial biomass C was strongly associated with soil microbial N (r = 0.80, p < 0.01) and P (r = 0.89, p < 0.01) content and soil microbial biomass N and P also showed a strong linear relationship (r = 0.92, p < 0.01). Soil microbial biomass exhibited weak seasonality and was highly influenced by altitude and abiotic variables. The significantly high microbial C, N and P during the rainy season (p < 0.01) and low microbial biomass during the winter season may be due to higher immobilization of nutrients from decomposing litter by microbes as the decomposition rate of litter and microbial activity are at their peak during the rainy period. The microbial C:N ratio indicated that soil fertility is influenced by species composition. Our findings suggested that high microbial biomass and low C:N ratios during the rainy season could be considered a nutrient conservation strategy of temperate mixed oak–pine forest ecosystems.
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Liyanage, Liyana Rallage Mahesh Chaminda, Muhammad Firdaus Sulaiman, Roslan Ismail, Gamini Perera Gunaratne, Randombage Saman Dharmakeerthi, Minninga Geethika Neranjani Rupasinghe, Amoda Priyangi Mayakaduwa, and Mohamed M. Hanafi. "Carbon Mineralization Dynamics of Organic Materials and Their Usage in the Restoration of Degraded Tropical Tea-Growing Soil." Agronomy 11, no. 6 (June 10, 2021): 1191. http://dx.doi.org/10.3390/agronomy11061191.
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Understanding carbon mineralization dynamics of organic amendments is essential to restore degraded lands. This study focused on the restoration potentials of tea-growing soils using organic materials available in tea ecosystems. The Selangor-Briah soil series association (Typic Endoaquepts) consisted of a high- (soil A) and a low-carbon (soil B) soils were incubated with different organic materials and released carbon dioxide (CO2) measured. Two kinetic models were applied to depict the mineralization process. Soil health parameters including microbial biomass carbon and nitrogen, dehydrogenase and catalase activities were determined to assess the restoration potentials. The parallel first-order kinetic model fitted well for all amendments. Gliricidia markedly enhanced the net cumulative CO2 flux in both soils. Charged biochar, tea waste and Gliricidia improved the microbial biomass carbon by 79–84% in soil A and 82–93% in soil B, respectively. Microbial quotients and biomass nitrogen were increased over 50 and 70% in amended soils, respectively. Dehydrogenase activity was significantly accelerated over 80% by compost, charged biochar and tea waste. Charged biochar remarkably increased the soil catalase activity by 141%. Microbial biomass, dehydrogenase and catalase activities, and cumulative CO2 flux were positively correlated (r > 0.452) with one another. The studied amendments showed greater potential in improving the soil quality, while charged biochar, raw biochar and compost enrich the soil recalcitrant C pool ensuring the soil health in long term. Even though biochar sequesters carbon, it has to be charged with nutrients to achieve the soil restoration goals.
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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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Lupwayi, N. Z., M. A. Monreal, G. W. Clayton, C. A. Grant, A. M. Johnston, and W. A. Rice. "Soil microbial biomass and diversity respond to tillage and sulphur fertilizers." Canadian Journal of Soil Science 81, no. 5 (November 1, 2001): 577–89. http://dx.doi.org/10.4141/s01-010.
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There is little information on the effects of S management strategies on soil microorganisms under zero tillage systems o n the North American Prairies. Experiments were conducted to examine the effects of tillage and source and placement of S on soil microbial biomass (substrate induced respiration) and functional diversity (substrate utilization patterns) in a canola-wheat rotation under conventional and zero tillage systems at three sites in Gray Luvisolic and Black Chernozemic soils. Conventional tillage significantly reduced microbial biomass and diversity on an acidic and C-poor Luvisolic soil, but it had mostly no significant effects on the near-neutral, C-rich Luvisolic and Chernozemic soils, which underlines the importance of soil C in maintaining a healthy soil. Sulphur had no significant effects on soil microbial biomass, and its effects on microbial diversity were more frequent on the near-neutral Luvisol, which was more S-deficient, than on the acidic Luvisol or the Chernozem. Significant S effects on microbial diversity were observed both in the bulk soil (negative effects, compared with the control) and rhizosphere (positive effects) of the acidic Luvisol, but all significant effects (positive) were observed in root rhizospheres in the other soils. Sulphur by tillage interactions on acidic Luvisolic soil indicated that the negative effects of S in bulk soil occurred mostly under zero tillage, presumably because the fertilizer is concentrated in a smaller volume of soil than under conventional tillage. Sulphate S effects, either negative or positive, on microbial diversity were usually greater than elemental S effects. Therefore, S application can have direct, deleterious effects on soil microorganisms or indirect, beneficial effects through crop growth, the latter presumably due to increased root exudation in the rhizosphere of healthy crops. Key Words: Biolog, conservation tillage, microbial biodiversity, rhizosphere, soil biological quality, S fertilizer type and placement
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Renella, Giancarlo. "Evolution of Physico-Chemical Properties, Microbial Biomass and Microbial Activity of an Urban Soil after De-Sealing." Agriculture 10, no. 12 (December 2, 2020): 596. http://dx.doi.org/10.3390/agriculture10120596.
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Recovery of soil fertility after de-sealing of urban soils is still poorly known. This work studied the time-related dynamics of soil physico-chemical and biochemical endpoints of urban soil in the city in Naples (Southern Italy), de-sealed for different time during construction works, that underwent colonization by volunteer plants. The results showed de-sealing decreased the soil bulk density and the soil pH value, increased the electrical conductivity (EC), total organic C (TOC) and extractable carbohydrates (TEC), total and inorganic N contents, soil basal respiration (SBR), soil microbial biomass C (MBC) and soil microbial biomass N (MBN), the substrate induced respiration (SIR) value, and enzyme activities involved in C, N, P and S mineralization. The TEC, total and inorganic N, SBR and microbial biochemical endpoints were higher in the de-sealed soils than those of an arable soil of the same area. The results show that de-sealed urban soils rapidly increase their physical, chemical and biological fertility even with no intervention, especially when they are colonized by volunteer plants.