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Adding biochar to paper mill biosolids (PB) amendments may affect PB mineralization rate and nitrogen (N) availability. The objective of this 224-day incubation study was to evaluate the effect of amending two PB types varying in carbon (C)/N ratio (PB1, C/N = 24; and PB2, C/N = 13) with three rates (0%, 2%, and 5%) of pine (Pinus strobus L.) biochar produced at 700 °C on the dynamics of total C, total N, mineral N, N mineralization rate, and microbial biomass C (MBC) and N (MBN) in two agricultural soils (Kamouraska clay and St-Antoine sandy-loam). Two reference treatments were also included, namely, mineral fertilization and unamended soil. Total soil C concentration remained stable over the incubation period, whereas a decrease in total soil N was observed in both soils. In comparison with the unamended soil, the application of PB significantly increased total N, NH 4 -N, NO 3 -N, net mineralized N, applied N mineralization rate, and MBC in both soils. In comparison with the application of PB alone, biochar addition increased total C and MBC but decreased NH 4 -N, NO 3 -N, net N mineralization, and applied N mineralization rate in both soils. The co-application of biochar and PB1 resulted in the sequestration of mineral N released, which was more pronounced in the Kamouraska clay soil. The co-application of biochar and PB2 resulted in moderate release of mineral N. This study showed that the co-application of biochar and PB can benefit agricultural soils by improving NO 3 -N retention in agroecosystems while increasing organic matter and promoting microbial biomass. [ABSTRACT FROM AUTHOR]

An incubation study was conducted under laboratory conditions to compare the effects of soil amendment of combined paper mill sludge (PS) and decomposed cow manure (DCM) on selected microbial indicators. A lateritic soil (Typic Haplustalf) was amended with 0 (control), 20 or 80tha−1 (wet weight) of PS or DCM. The amended soils were then adjusted to 60% water holding capacity (WHC) or submerged conditions, and incubated at 27°C in dark for up to 120days (d). The microbial biomass C (MBC), the basal soil respiration and the enzyme activities of the β-glucosidase, acid phosphatase and sulphatase were analyzed at day 15, 30, 45, 60 and 120. Compared to the unamended soil (control), the MBC, the basal soil respiration and the enzyme activities increased with the rate of PS and DCM. At similar rate, the DCM treatment increased significantly the MBC, the soil respiration and the enzyme activities compared to the PS treatment. Also, the water regimes affected the microbial activities. At 60% WHC, the MBC and soil respiration increased during the first 30d and decreased thereafter. The enzyme activities showed similar trends, where they increased for the first 60d, and decreased thereafter. In contrast, under submerged condition, the MBC and enzymes activities declined during 120d, whereas the soil respiration increased. Compared to the control, the used of PS and DCM had no negative impact of the soil microbial parameters, even at the highest application rate. Long-term field experiments are required to confirm these laboratory results. [Copyright &y& Elsevier]

Studies regarding soil quality and health often need to be up-to-date, as they feed new models for quantifying agricultural impacts on the environment. This study was established to understand how types of vineyard cultivation (organic and conventional) affect soil chemical and microbial attribute dynamics throughout different seasons. Vineyard management had a strong effect on chemical soil attributes. Organic carbon and phosphorus were 2.8 and 2.0 times greater, respectively, in organic vineyards than in conventional vineyards. Metabolic quotient (qCO2) values were lowest in summer and autumn, with an average of 2.31-2.49 µg C-CO2 h-1 g-1 soil, under organic management, indicating greater microbial growing efficacy. Regardless of season and sampling position, organic soil had a higher C microbial biomass than conventional vineyards, with values ranging from 179.79 to 284.71 µg g-1 soil, which were similar to those of the adjacent forest soil. Overall, there were increases in both the microbial and the chemical attributes of soil under organic vineyards compared relative to conventional management, which might have been due to the continuous input of organic matter, crop rotation, and alternative plant protection and fertilizer compounds used in organic farming. [ABSTRACT FROM AUTHOR]

Composting is an alternative method to dispose of de-inking paper sludge (DPS). Today, few studies have investigated the water-soluble carbon (WSC) substances as indicators of the decomposition process and the microbial changes taking place during the composting of DPS. Accordingly, the goal is to study their dynamics during the composting of DPS at three nitrogen levels, 0.6%, 0.7% or 0.9% total N, using mechanical turning. The changes in WSC substances, microbial biomass carbon (MBC) and, total and DPS microbial populations were monitored during 24 weeks. Also, microorganisms were identified and tested for the production of selected enzymes. Regardless of N treatments, the dynamic of WSC substances indicated that cellulose and hemicellulose fractions of DPS fibers were mainly biodegraded during the first 8 weeks while the more resistant carbon (C) fractions were biodegraded thereafter. MBC also evolved regardless of N treatments but was correlated to WSC substances. Its high values decline mostly after 12 weeks indicating the exhaustion of this source of C energy for microbial growth and the stabilisation of DPS organic matter. The dynamic and identified microorganisms were comparable to those observed in other composting processes. However, the results pointed out that those mostly implicated in the hydrolysis of DPS fibers were the thermophilic actinomycetes and fungi and, by comparison to the 0.6% or 0.7% N treatment, they decreased in presence of the 0.9% N treatment. Most microorganisms were hemicellulolytic bacteria, while actinomycetes and fungi were capable of degrading a wide variety of substrates. Overall, dynamics of WSC substances and microbial populations indicated that during composting, DPS decomposition obey a two phase decay while, contrary to the lowest N treatment, the 0.9% N treatment has slowed down this process by harming the important microbial populations implicated in the degradation of DPS fibers. [Copyright &y& Elsevier]

Summary: Commercially processed vermicomposts, produced from food wastes, paper wastes and cattle manure, were applied to 8.25m2 field plots, at rates of 10 or 20t/ha in 1999 and 5 or 10t/ha in 2000, to evaluate their effects on the growth and yields of peppers (Capsicum annuum) var. King Arthur. The vermicomposts were incorporated into the upper 10cm of soil and supplemented, based on chemical analyses, with amounts of inorganic NPK fertilizers calculated to equalize initially with the rates of 95-95NKkg/ha applied to the inorganic fertilizer control plots. Phosphorus was determined to be adequate in soils at the experiment site so was not added. All treatments were replicated four times in a randomized complete block design. The vermicompost applications increased the growth and yields of peppers significantly; including increased leaf areas, plant shoot biomass, marketable fruit weights and decreased yields of non-marketable fruit. Application of vermicomposts to soils increased their microbial biomass and dehydrogenase activity. Humic materials and other plant growth-influencing substances, such as plant growth hormones, produced by microorganisms during vermicomposting, and produced after increased microbial biomass and activity in soils, may have been responsible for the increased pepper growth and yields, independent of nutrient availability. [Copyright &y& Elsevier]

Nitrogen cycling in northern temperate forest ecosystems could change under increasing atmospheric CO2 and tropospheric O3 as a result of quantitative and qualitative changes in plant litter production. At the Aspen Free Air CO2–O3 Enrichment (FACE) experiment, we previously found that greater substrate inputs to soil under elevated CO2 did not alter gross N transformation rates in the first 3 years of the experiment. We hypothesized that greater litter production under elevated CO2 would eventually cause greater gross N transformation rates and that CO2 effects would be nullified by elevated O3. Following our original study, we continued measurement of gross N transformation rates for an additional four years. From 1999 to 2003, gross N mineralization doubled, N immobilization increased 4-fold, but changes in microbial biomass N and soil total N were not detected. We observed year-to-year variation in N transformation rates, which peaked during a period of foliar insect damage. Elevated CO2 caused equivalent increases in gross rates of N mineralization (+34%) and NH immobilization (+36%). These results indicate greater rates of N turnover under elevated CO2, but do not indicate a negative feedback between elevated CO2 and soil N availability. Elevated O3 decreased gross N mineralization (−16%) and had no effect on NH immobilization, indicating reduced N availability under elevated O3. The effects of CO2 and O3 on N mineralization rates were mainly related to changes in litter production, whereas effects on N immobilization were likely influenced by changes in litter chemistry and production. Our findings also indicate that concomitant increases in atmospheric CO2 and O3 could lead to a negative feedback on N availability. [ABSTRACT FROM AUTHOR]

Tropical soils withstand heavy pressure due to deforestation as a result of the change in land use, decreasing their quality. Traditionally, the quality of soil has been based on physical and chemical indicators; however, the biological ones can predict variations in the quality, in an early and effective way. In this research, the microbiological quality of soils from two ecosystems was evaluated, one from the Cumbaza Sub-Basin (CSB) and the other from Degraded Pastures at Cuñumbuque (DPC), both in San Martín, Peru. The physicochemical characteristics were studied and the microbial populations of Total Bacteria (TB), Sporulated Bacteria (SB), Total Fungi (TF), Actinobacteria (ACT), and parameters of microbial activity such as Basal Respiration (BR), Microbial Biomass (MB), Metabolic Quotient (qCO2) and Microbial Quotient (qMIC). According to the Principal Component Analysis (PCA), the soils of the CSB had on average a lower biological quality compared to the DPC soils. The PCA discriminated that the microbial populations of TB, SB, ACT and MB represented effective microbiological indicators to evaluate the quality of the soils, in this respect the soils of Shapumba, Chontal, Aucaloma and Vista Alegre are degraded and require the application of new technologies and public policies for their recovery. [ABSTRACT FROM AUTHOR]

Slit seeding (sowing into shallow cuts to the soil surface) was evaluated on coal mine reclamation in the North Bohemian Brown Coal Basin (Czech Republic) between 2001 and 2008, on plots both with and without biodegradable waste enrichment. Prior to experimentation (in 2000, once) were applied dehydrated, anaerobically digested wastewater sludge, 200 (41) t/ha fresh mass (dry mass), together with paper mill waste, 400 (131) t/ha, and bark substrate Envima, 400 (145) t/ha. Spontaneous herbaceous cover was enhanced each end of April from 2001 to 2003 by slit seeded grass-legume mixture containing Festuca pratensis L. (46%); Lotus corniculatus L. (22%); Coronilla varia L. (18%); Festuca rubra L. (9%); and Medicago lupulina L. (5%). All slit seeded species proliferated better on surface strip mine deposits without biodegradable waste enrichment and brought beneficial changes in a number of parameters over the ensuing five years due to lower competition with native expanding eutrophic species including Calamagrostis epigejos L.; Cardaria draba L.; Urtica dioica L.; and Galium aparine L. Available organic carbon (extracted from field-moist soil by 0.5 mol/L K2SO4) showed a notable tendency toward values 10-66 mg C/kg DM (dry mass), microbial biomass 302-1131 mg C/kg DM, basal respiration 3.9-5.8 mg C/kg DM/h, and metabolic quotient (basal respiration/microbial biomass carbon) × 1000 = 5.2-7.9.

Abstract: Kemmitt et al. (Kemmitt, S.J., Lanyon, C.V., Waite, I.S., Wen, Q., Addiscott, T.M., Bird, N.R.A., O''Donnell, A.G., Brookes, P.C., 2008. Mineralization of native soil organic matter is not regulated by the size, activity or composition of the soil microbial biomass – a new perspective. Soil Biology & Biochemistry 40, 61–73) recently proposed the “Regulatory Gate” hypothesis, which states that decomposition of soil organic matter (SOM) is regulated solely by abiotic factors. Without studying the mechanisms of such regulation, Kemmitt with coauthors challenged the classical Winogradsky theory of soil microbiology and questioned the concept of autochtonous and zymogenous microbial populations. In this letter, we revive the significance of microbial activity for SOM decomposition especially for the short-term (hours to weeks) processes and show that the “Regulatory Gate” is (micro)biologically driven. We explain the results of the three experiments in from a microbiological point of view and suggest that SOM decomposition is mainly regulated by exoenzymes. We criticize the abiotic Regulatory Gate hypothesis based on bottleneck processes and pools limiting the SOM decomposition rate, comparison of constant and changing environmental conditions, as well as the connection between community structure and functions. We explain the results of according to the properties of soil microbial community: functional redundancy and inconsistency between the excessive (but largely inactive) pool of total microbial biomass and the real mineralization activity. Finally, we suggest that to gain new perspectives on SOM decomposition and many other biochemical processes, future studies should focus on hot spots of (micro)biological activity (i.e., the rhizosphere, drillosphere, detritosphere, biopores, etc.) rather than on the bulk soil. [Copyright &y& Elsevier]

Seven years of twelve treatment combinations of annual compost, wood chips, shredded paper mulch, or mow-and-blow ground cover and poultry litter, organic commercial, or no fertilizer control surface applications on soil decomposition and microbial activity were evaluated in an organic apple orchard. Because soil amendments were surface applied, microbial biomass, enzyme activities, organic matter, dissolved organic carbon (DOC) and dissolved total nitrogen (N), ammonium-N, and nitrate-N concentrations were measured in March from 2007 to 2013 at 0–0.1 and 0.1–0.3 m soil depths where biochemical activity and nutrient availability were expected to be greatest and where tree roots were expected to be located. Ground covers were applied by volume based on horticulture management and these applications rather than fertilizers were stronger drivers of soil nutrient and microbial property responses. Dehydrogenase and β-glucosaminidase activities were 1.5 times greater in 2008 and 2009, respectively, under mow-and-blow as compared to other ground covers. Enzymes may be sensitive indicators separating living and non-living mulch effects on soil during establishment of fruit tree orchards in the southeastern U.S. Organic matter (OM) and soil water content increased in all ground covers during the study. At greatest differences, soil OM and DOC were more than twice and dissolved total N and nitrate-N were more than three and five times greater in compost than other ground cover treatments. Relative differences between compost and other ground covers did not persist to the same extent during the seven years. Orchard floor management may need different strategies during different stages of orchard development. [ABSTRACT FROM AUTHOR]

Copyright of China Condiment is the property of China Condiment and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Global warming intensifies the hydrological cycle, which results in changes in precipitation regime (frequency and amount), and will likely have significant impacts on soil respiration (Rs). Although the responses of Rs to changes in precipitation amount have been extensively studied, there is little consensus on how Rs will be affected by changes in precipitation frequency (PF) across the globe. Here, we synthesized the field observations from 296 published papers to quantify the effects of PF on Rs and its components using meta-analysis. Our results indicated that the effects of PF on Rs decreased with an increase in background mean annual precipitation. When the data were grouped by climate conditions, increased PF showed positive effects on Rs under the arid condition but not under the semi-humid or humid conditions, whereas decreased PF suppressed Rs across all the climate conditions. The positive effects of increased PF mainly resulted from the positive response of heterotrophic respiration under the arid condition while the negative effects of decreased PF were mainly attributed to the reductions in root biomass and respiration. Overall, our global synthesis provided for the first time a comprehensive analysis of the divergent effects of PF on Rs and its components across climate regions. This study also provided a framework for understanding and modeling responses of ecosystem carbon cycling to global precipitation change. [ABSTRACT FROM AUTHOR]

Alpine ecosystems are sensitive to global climate change-factors, which directly or indirectly affect the soil microbial biomass stoichiometry. In this paper, we have compared the soil microbial biomass stoichiometry ratios of alpine ecosystems using the global average values. In the comparison, the responses and mechanisms of soil microbial biomass stoichiometry to nitrogen deposition, altered precipitation, warming, and elevated atmospheric carbon dioxide (CO2) concentration in the alpine ecosystem were considered. The alpine ecosystem has a higher soil microbial-biomass-carbon-to-nitrogen ratio (MBC:MBN) than the global average. In contrast, the soil microbial-biomass-nitrogen-to-phosphorus (MBN:MBP) and carbon-to-phosphorus ratios (MBC:MBP) varied considerably in different types of alpine ecosystems. When compared with the global average values of these ratios, no uniform pattern was found. In response to the increase in nitrogen (N) deposition, on the one hand, microbes will adopt strategies to regulate extracellular enzyme synthesis and excrete excess elements to maintain stoichiometric balance. On the other hand, microbes may also alter their stoichiometry by storing excess N in their bodies to adapt to the increased N in the environment. Thus, a decrease in MBC:MBN and an increase in MBN:MBP are observed. In addition, N deposition directly and indirectly affects the soil fungal-to-bacterial ratio (F:B), which in turn changes the soil microbial biomass stoichiometry. For warming, there is no clear pattern in the response of soil microbial biomass stoichiometry in alpine ecosystems. The results show diverse decreasing, increasing, and unchanging patterns. Under reduced precipitation, microbial communities in alpine ecosystems typically shift to a fungal dominance. The latter community supports a greater carbon-to-nitrogen ratio (C:N) and thus an increased soil MBC:MBN. However, increased precipitation enhances N effectiveness and exacerbates the leaching of dissolved organic carbon (DOC) and phosphorus (P) from alpine ecosystem soils. As a result, a decrease in the soil MBC:MBN and an increase in the soil MBN:MBP are evident. Elevated atmospheric CO2 usually has little effect on the soil MBC:MBN in alpine ecosystems, mainly because of two reasons. These are: (i) N is the main limiting factor in alpine ecosystems, and (ii) alpine ecosystems accumulate higher soil organic carbon (SOC) and microbes and preferentially decompose "old" carbon (C) stocks. The response of soil microbial stoichiometry to global climate change factors in alpine ecosystems is diverse, and the impact pathways are complex. Future studies need to focus on the combined effects of multiple global climate change factors on microbial stoichiometry and the mechanism of microbial stoichiometric balance. [ABSTRACT FROM AUTHOR]

A way of valorise the solid by-products resulting from industrial biosyntheses is to use them as such to fertilize agricultural soils or to obtain new types of fertilizers. Two types of fertilizers obtained with spent microbial biomass were evaluated regarding the impact generated on the waters as a result of potential nutrient loss processes through washing throughout rainwater. The tests were carried out in the lab, in glass columns filled with a mixture of red-brown soil, sand, and fertilizers, the last one added in quantities corresponding to a fertilization norm of 200 kg SA/ha. For each experimental variant, an average pluviometry flow rate of 14 L/m² was simulated; in each column, water was added at intervals of 1; 4; 7, and 15 days. The nutrients lost by leaching were assessed after each interval. The obtained results showed that fertilizers formulated with microbial biomass lose (77.9-85.11)% P2O5 and (76.2-90)% K2O in 24 h, compared to classic fertilizers, which lose 75% P2O5 through leaching, respectively 86.5% K2O. Because the behaviour of fertilizers formulated with microbial biomass is similar to that of complex fertilizers, was estimated that the impact generated by the use of fertilizers with microbial biomass on the water is insignificant. [ABSTRACT FROM AUTHOR]

Bacillus subtilis is a non-pathogenic, sporulating, Gram-positive bacteria with pronounced antimicrobial and metabolic activity and great potential for wide application in various fields. The aim of this paper was to determine the optimum B. subtilis NCIM 2063 growth conditions and to scale up biomass production from shake flasks to a bioreactor level. The critical growth parameters and their interaction effects were studied using Box-Behnken experimental design and response surface methodology. Developed model equations were statistically significant with good prediction capability. It was found that during shake flask cultivation glucose should be added in concentration up to 5 g L-1 in DSM medium, OTR at 10 mol m-3 h-1 and temperature of 33 °C, to achieve the maximum number of viable cells and spores. To scale up the process from shake flasks to the bioreactor level kLa was used as a main criterion. Scale up effect was evaluated by comparing the growth kinetics in the shake flasks and in a laboratory bioreactor. The total number of cells obtained in the bioreactor was 4.57×109 CFU mL-1 which is 1.41 times higher than the number of cells in the shake flasks (3.24×109 CFU mL-1), proving that the scale-up procedure was conducted successfully. [ABSTRACT FROM AUTHOR]

This paper evaluates the seasonal changes of microbial biomass carbon (MBC) and microbial biomass nitrogen (MBN) contents as an indicator of urban soil health. Our research was conducted in six horticultural urban soils in Krakow that have been cultivated for centuries. We investigated the temporal dynamics of microbial biomass C and N in soil samples from 0 to 20 cm depth taken in spring, summer and autumn. The study plots were placed in suburban areas as well as in the centre of the city to distinguish whether the detected effect of altered soil properties is similar to suburban areas. Soil microbial biomass was determined by the chloroform fumigation–extraction (CFE) method. The concentrations of MBC and MBN were measured in the field‐moist soil samples. MBC in the soil ranged from 226.5 to 742.7 mg kg−1 and MBN from 62.7 to 359.6 mg kg−1 expressed in dry mass. Repeated‐measures analysis of variance (ANOVAR, match‐model) was performed to test the main effects and interactions of temporal changes for MBC and MBN. There were significant differences only between MBN concentration in summer and autumn (p <.05). Principle component analysis (PCA) gave insightful results for the whole soil profile. Detrended canonical correspondence analysis (DCCA) indicated that the most explanatory variables in the studied time period were concentration of silt, total nitrogen, MBN and MBC content in the surface layer. Molar ratios of total organic carbon and total nitrogen (TOC:TN) indicated that microbial activity for C and N is enhanced by stoichiometry demands and therefore may be important for vegetation. [ABSTRACT FROM AUTHOR]

Soil gross nitrogen (N) mineralization (GNM), a key microbial process in the global N cycle, is mainly controlled by climate and soil properties. This study provides for the first time a comprehensive analysis of the role of soil physicochemical properties and climate and their interactions with soil microbial biomass (MB) in controlling GNM globally. Through a meta‐analysis of 970 observations from 337 published papers from various ecosystems, we found that GNM was positively correlated with MB, total carbon, total N and precipitation, and negatively correlated with bulk density (BD) and soil pH. Our multivariate analysis and structural equation modeling revealed that GNM is driven by MB and dominantly influenced by BD and precipitation. The higher total N accelerates GNM via increasing MB. The decrease in BD stimulates GNM via increasing total N and MB, whereas higher precipitation stimulates GNM via increasing total N. Moreover, the GNM varies with ecosystem type, being greater in forests and grasslands with high total carbon and MB contents and low BD and pH compared to croplands. The highest GNM was observed in tropical wet soils that receive high precipitation, which increases the supply of soil substrate (total N) to microbes. Our findings suggest that anthropogenic activities that affect soil microbial population size, BD, soil substrate availability, or soil pH may interact with changes in precipitation regime and land use to influence GNM, which may ultimately affect ecosystem productivity and N loss to the environment. [ABSTRACT FROM AUTHOR]

The development of a microbial community on cellulose (cellophane film and filter paper) buried in waterlogged soil was observed under a microscope. Throughout the decomposition of the cellulose, the biomass, immobilized N, ATP and gas metabolism of the microbial community were examined. As cellulose decomposition progressed, a microbial succession was recognized. This succession was divided into two stages. In the first stage, a few types of cellulolytic microorganisms predominated on the cellulose. Vigorous decomposition of the cellulose was accompanied by a rapid increase in microbial biomass, and H was evolved from the microbial community on the cellulose. In the second stage, the rate of cellulose decomposition was slow. The cellulose remaining was thickly covered with various types of microoganisms. The H produced was consumed by the microorganisms closely adhering to the remaining cellulose. In addition, non-cellular organic N accumulated on the remaining cellulose. A large part of the microorganisms seemed to be dormant in this stage. The trends in this microbial succession were similar to those found in ecosystem successions. [ABSTRACT FROM AUTHOR]

Using zeolite-rich tuffs for improving soil properties and crop N-use efficiency is becoming popular. However, the mechanistic understanding of their influence on soil N-processes is still poor. This paper aims to shed new light on how natural and NH4+-enriched chabazite zeolites alter short-term N-ammonification and nitrification rates with and without the use of nitrification inhibitor (DMPP). We employed the 15N pool dilution technique to determine short-term gross rates of ammonification and nitrification in a silty-clay soil amended with two typologies of chabazite-rich tuff: (1) at natural state and (2) enriched with NH4+-N from an animal slurry. Archaeal and bacterial amoA, nirS and nosZ genes, N2O-N and CO2-C emissions were also evaluated. The results showed modest short-term effects of chabazite at natural state only on nitrate production rates, which was slightly delayed compared to the unamended soil. On the other hand, the addition of NH4+-enriched chabazite stimulated NH4+-N production, N2O-N emissions, but reduced NO3−-N production and abundance of nirS-nosZ genes. DMPP efficiency in reducing nitrification rates was dependent on N addition but not affected by the two typologies of zeolites tested. The outcomes of this study indicated the good compatibility of both natural and NH4+-enriched chabazite zeolite with DMPP. In particular, the application of NH4+-enriched zeolites with DMPP is recommended to mitigate short-term N losses. [ABSTRACT FROM AUTHOR]

This paper describes typical and humic petrozem soils developing in the most high-altitude (goltsy) zone of the Khibiny Mountains under three predominant types of primitive plant communities representing different stages of the primary succession. The profiles of such soils are not differentiated by the content of most elements, except for phosphorus concentrated in the surface organogenic horizons. By their chemical and physicochemical properties, soils of the cold mountain (goltsy) desert are similar to Entic Folic Podzols formed under dwarf-shrub vegetation in the mountain-tundra located downslope. The biological activity of petrozem soils is lower than or comparable to that in soils of dwarf-shrub tundra. It is established that the microbial activity increases and soil organic matter stabilizes when the vegetation becomes more patterned. Overall, microbial communities of petrozem soils are well adapted to extreme environmental conditions. [ABSTRACT FROM AUTHOR]

Copyright of Oltenia, Studii si Comunicari Seria Stiintele Naturii is the property of Museum of Oltenia Craiova and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Recycled manure solids (RMS) are dried cow dung processed using a manure dewatering machine and subsequently sun-dried to ~ 20% moisture. Benefits of RMS include abundant availability, low cost, and eco-friendliness, but its use as bedding material for cows is hindered by a moisture content that promotes microbial growth. This in vitro study evaluated impacts of calcium hydroxide (CH; 5 and 7.5%) and sodium hydrosulphate (SHS; 6 and 8%), independently and in combinations, at various depths of RMS, on physicochemical and microbial properties. The CH-treated groups had increased pH and reduced moisture on Day 0. Incorporating 7.5% CH + 6% SHS at 15–20 cm, and 7.5% CH + 8% SHS at all depths, effectively suppressed Escherichia coli and Klebsiella spp. Furthermore, a combination of 7.5% CH + 8% SHS at 20 cm inhibited coliform growth, whereas 7.5% CH with 6% SHS inhibited Streptococcus spp. In conclusion, a combination of 7.5% CH with either 6 or 8% SHS at a depth of 15 cm in RMS was particularly effective in controlling environmental mastitis-causing pathogens, specifically E. coli and Klebsiella spp. [ABSTRACT FROM AUTHOR]

This study aimed to explore the possibility of improving the fertility of lunar soil through the reuse of resources by composting household waste and collecting composting fermentation broth. The fermentation broth was used to culture a simulated lunar soil at different concentration gradients for 30 days under aerobic and anaerobic conditions. Microbial biomass carbon and nitrogen content, typical mineral elements, and the microbial community were tested to determine whether the fertility of the lunar soil had improved. Results showed that the microorganisms in the simulated lunar soil samples successfully adhered and grew under both aerobic and anaerobic experimental conditions. The simulated lunar soil samples cultured in the anaerobic environment outperformed those in the aerobic environment regarding microbial biomass growth and water-soluble mineral elements. The study results create opportunities for the future reuse of domestic garbage on the lunar base, providing a technical basis for the in situ reuse of lunar soil resources for plant cultivation. [ABSTRACT FROM AUTHOR]

Most studies about the effects of N addition on soil microbial biomass evaluate soil microbial and physicochemical characteristics using single-test methods, and these studies have not been integrated and analyzed to comprehensively assess the impact of N fertilization on soil microbial biomass. Here, we conduct a meta-analysis to analyze the results of 86 studies characterizing how soil microbial biomass C (MBC), N (MBN), and P (MBP) pools respond to exogenous N addition across multiple land use types. We found that low N addition (5–50 kg/hm2) rates significantly affect soil microbial biomass, mainly by increasing MBC but also by decreasing MBP and significantly increasing MBC/MBP. N addition affects soil physicochemical properties, significantly reducing pH and significantly increasing the soil dissolved organic N and inorganic N content. Our analysis also revealed that the effects of N application vary across ecosystems. N addition significantly decreases MBP and total P in planted forests but does not significantly affect soil microbial biomass in grasslands. In farmland soil, N addition significantly increases total P, NH4+, NO3−, MBN, and MBP but significantly decreases pH. Although N addition can strongly influence soil microbial biomass, its effects are modulated by ecosystem type. The addition of N can negatively affect MBC, MBN, and MBP in natural forest ecosystems, thereby altering global ecosystem balance. [ABSTRACT FROM AUTHOR]

Microbial biomass in calcareous, leached and podzolic chernozems has been studied in connection with the evaluation of soil degradation processes as a result of a long-term arable use. Experimental sites located in the southern and northern zone of the Republic of Moldova have been tested in August and September 2021. Microbial biomass sampling was carried out in 6 profiles per soil horizons to a depth of 150-240 cm. The highest values of microorganisms' abundance were registered in the upper horizon in chernozems of the natural ecosystem. Microbial biomass content constituted 535.0-1168.6 μg C g-1 soil and was much more than in arable chernozems. Microbiological indices in soil profiles decreased with the depth. Microbial biomass reserves in chernozems in the 0-100 cm layer has been reducing from natural chernozems (4925.2-11816.4 kg ha-) to old-arable chernozems (2547.3-6659.2 kg ha-). The microbial biomass was connected with humus content. Correlation coefficients constitute 0.94. The binding effect between microbial biomass and humus content decreases from natural chernozems (R2 = 0.94) to arable ones (R2 = 0.64). [ABSTRACT FROM AUTHOR]

The phenomenon of water eutrophication has increased over the world. Eutrophication involves the excessive algal growth due to increased influx of nutrients, leading to reduced level of dissolved oxygen in water. A regular inflow of P is mainly responsible for eutrophication. The present study was designed to monitor the occurrence and assessment of eutrophication in Rawal lake, Islamabad. Three different types of parameters viz., dissolved phosphorus in lake water, microbial biomass and phosphorus fractions in sediments were analyzed for its assessment. Water samples were collected and analyzed for dissolved phosphorus on biweekly basis while sediments from lake were collected and analyzed for phosphorus fractions in October, 2007 and July, 2008. Rawal lake was categorized as oligotrophic in October 2007, moderately eutrophic in January, and eutrophic in June and July, 2008 with a maximum level of dissolved phosphorus of 0.063 mg L-1. The rainfall was recorded highest of 160 mm in July, 2008 depicting maximum inflow of P into the lake. Among the various P-fractions, acid-P and CaCl2-P were found to be the highest with 4.25 mg L-1 concentration, respectively, in July 2008. The water samples were filtered through 0.045 μm filter paper and then assessed for microbial mass. Residues left on filter paper were tested for microbial biomass, which increased from 5.8-15 μg L-1, from October, 2007 to July, 2008. The results clearly showed that the phenomenon of eutrophication do exist in Rawal lake, both at the centre and bank. The possible sources of contamination seemed to be the adjoining human settlement and mushroom growth of poultry sheds in and around the catchment area of Rawal lake. It is necessary to check these sources of contamination to protect a valuable source of drinking water for Rawalpindi and Islamabad citizens [ABSTRACT FROM AUTHOR]

Amino sugars are important indices for the contribution of soil microorganisms to soil organic matter. Consequently, the past decade has seen a great increase in the number of studies measuring amino sugars. However, some uncertainties remain in the interpretation of amino sugar data. The objective of the current opinion paper is to summarize current knowledge on amino sugars in soils, to give some advice for future research objectives, and to make a plea for the correct use of information. The study gives an overview on the origin of muramic acid (MurN), glucosamine (GlcN), galactosamine (GalN), and mannosamine (ManN). Information is also provided on measuring total amino sugars in soil but also on compound-specific δ13C and δ15N determination. Special attention is given to the turnover of microbial cell-wall residues, to the interpretation of the GlcN/GalN ratio, and to the reasons for converting fungal GlcN and MurN to microbial residue C. There is no evidence to suggest that the turnover of fungal residues generally differs from that of bacterial residues. On average, MurN contributes 7% to total amino sugars in soil, GlcN 60%, GalN 30%, and ManN 4%. MurN is highly specific for bacteria, GlcN for fungi if corrected for the contribution of bacterial GlcN, whereas GalN and ManN are unspecific microbial markers. [ABSTRACT FROM AUTHOR]

Water is an important constraint on alfalfa (Medicago sativa) production in arid and semiarid areas, and alternate irrigation in root areas has water-saving potential for alfalfa production. To investigate the impact of alternate partial root-zone irrigation (APRI) on the rhizosphere soil microorganisms of alfalfa, this study subjected alfalfa plants to different irrigation methods and irrigation levels. The growth status and rhizosphere soil microbial community diversity of alfalfa plants under alternate root-zone watering treatment were analyzed through laboratory experiments and high-throughput sequencing. The results showed that at soil moisture levels of 80% field moisture capacity (FMC) and 60% FMC, APRI had no significant impact on the biomass or nodule number of alfalfa. However, 40% FMC significantly reduced the individual plant dry weight, chlorophyll content, and nodule number of the alfalfa plants. APRI increased the relative abundance of Actinomycetes in the alfalfa rhizosphere soil. Moreover, at 60% FMC, the MBC and MBN of rhizosphere, relative abundance of Actinobacteria and unclassified K fungi and Chao 1 index of bacteria significantly increased under APRI treatment. While relative abundance of Ascomycetes and Proteobacteria in the alfalfa rhizosphere significantly reduced under 60% FMC + APRI treatment. In summary, under the same irrigation conditions, APRI did not significantly affect the growth of alfalfa in the short term. And 60%FMC + APRI treatment did significantly affect the groups, structure and diversity of the rhizosphere soil microbial communities. [ABSTRACT FROM AUTHOR]

Processes driving nutrient retention in stormwater green infrastructure (SGI) are not well quantified in water-limited biomes. We examined the role of plant diversity and physiochemistry as drivers of microbial community physiology and soil N dynamics post precipitation pulses in a semi-arid region experiencing drought. We conducted our study in bioswales receiving experimental water additions and a montane meadow intercepting natural rainfall. Pulses of water generally elevated soil moisture and pH, stimulated ecoenzyme activity (EEA), and increased the concentration of organic matter, proteins, and N pools in both bioswale and meadow soils. Microbial community growth was static, and N assimilation into biomass was limited across pulse events. Unvegetated plots had greater soil moisture than vegetated plots at the bioswale site, yet we detected no clear effect of plant diversity on microbial C:N ratios, EEAs, organic matter content, and N pools. Differences in soil N concentrations in bioswales and the meadow were most directly correlated to changes in organic matter content mediated by ecoenzyme expression and the balance of C, N, and P resources available to microbial communities. Our results add to growing evidence that SGI ecological function is largely comparable to neighboring natural vegetated systems, particularly when soil media and water availability are similar. [ABSTRACT FROM AUTHOR]

The influence of catch crop (field pea) management and the time of its application [plots with autumn (A.I.) or spring (S.I.) biomass incorporation vs. treatments without catch crop (C) use] on the activity of five soil enzymes associated with C- (CMC-cellulase—CEL, β-glucosidase—βG, invertase—INV) and N-cycling (urease—UR, nitrate reductase—NR), the content of mineral N, and the content of microbial biomass C and N (MBC, MBN) were evaluated in a 3-year experiment (2009–2011). Field pea was sown in the first half of August and the biomass was incorporated into the soil in the second half of October in 2008, 2009, and 2010 or left as a mulch during the winter and mixed with the soil in spring. The enzymatic and microbial properties were determined in soil samples collected from spring barley experimental plots four times a year (2009, 2010, and 2011): in March (before sowing of barley), in May (during the tillering phase), in June (during the shooting phase), and in August (after barley harvesting). Neither the catch crop management nor the sampling date had any effect on the content of total organic carbon (CORG) or total nitrogen (Nt). The incorporation of filed pea biomass significantly enhanced the soil mineral N content (up to 30%), as well as the microbial and enzymatic variables, compared to the control soil. The spring use of field pea biomass significantly increased the content of microbial biomass C (2009 and 2011) in contrast to autumn incorporation. On the other hand, the biomass-N and the activity of the studied enzymes did not reveal statistically significant changes (or the results were inconsistent) as regards the time of catch crop biomass incorporation. The assessed variables (except for CORG, Nt, microbial biomass N) showed significant seasonal variability, but the changes were not clear or associated with a specific property. However, we found one similarity; the majority of the determined variables were the highest in May and/or June. Our data confirmed that catch crops play a key function in the management of agroecosystems. Plant biomass incorporated into soil is a source of organic matter, which increases nutrient concentrations and enhances soil biological activity. Because the time of catch crop application did not reveal consistent changes in the studied properties, both spring and autumn applications can be recommended as a suitable practice in modern agriculture. [ABSTRACT FROM AUTHOR]