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Abstract\nNovelty statementEnriched biochar with improved properties and functionality can play a significant role in providing sustainable solutions for mitigating heavy metal contamination in soil. In this experiment, the effects of solid and enriched biochars (potassium-enriched biochar (BC-K), magnesium-enriched biochar (BC-Mg), both individually and combined) were examined on soil microbial and enzyme activities, as well as nutrient uptake by basil plants cultivated in a soil with three levels of arsenic (nontoxic, 50 mg As kg−1 soil, and 100 mg As kg−1 soil). Biochar-related treatments, increased soil organic matter (65–76%), while decreased availability of arsenic (6–55%) in the soil. The microbial biomass carbon (by about 123%) and soil basal respiration (by about 256%), and soil enzymatic activities (β-glucosidase, urease, alkaline phosphatase, and dehydrogenase) were enhanced by enriched biochars under arsenic toxicity. The solid and particularly enriched biochars decreased arsenic content and improved nitrogen and phosphorus contents of roots and shoots, root length, root activity, and root and shoot biomass in basil plants. Therefore, it is conceivable to suggest that enriched biochars are superior treatments for improving nutrient absorption rates and basil growth under arsenic toxicity through decreasing arsenic mobility and increasing soil microbial activities.Nutrient-enriched biochars with improved physicochemical properties could help to increase plant productivity, especially under heavy metal-contaminated soils. High arsenic adsorbing capacity of nano-Mg- and K-enriched biochars reduced arsenic availability and improved soil microbial activities involved in nutrient metabolism. [ABSTRACT FROM AUTHOR]

Background Aims Methods Results Conclusions Liquid organic fertilizer (LOF) and root exudates contain easily decomposable carbon that can stimulate microbial growth. It is unknown what role the amount of organic matter (OM) in the growing media, and potential interactions between root presence and LOF, might play in enhancing the breakdown of OM.The aim was to better understand how the decomposition rate of plant litter is affected by added fertilizer, plant presence, and growing media OM content.A container experiment was conducted with and without tomato plants (Solanum lycopersicum L.; Heinz 5608 variety) present to evaluate the effect of three one‐time fertilizer additions (no fertilizer, LOF, and synthetic fertilizer) on litter decomposition rate. The equivalent amount of nitrogen (N), phosphorus (P), and potassium(K) was added in both fertilizer treatments. The experiment was conducted using two growing media, one containing high OM and one with negligible OM.The presence of tomato roots stimulated litter decomposition in high OM media, but not in low OM media. Adding LOF did not affect decomposition in either growing medium. Adding synthetic fertilizer led to a negative priming effect in low OM media when roots were present. The rate of decomposition was not affected by root traits.When ample OM was available, the presence of plant roots had a strong positive impact on litter decomposition. In both low and high OM media, a one‐time addition of fertilizer had minimal or negative effects on litter decomposition. We speculate that the continuous nature of root exudation leads to sustained changes in the microbial population (both community composition and size). Boosting root length growth via the one‐time addition of inorganic fertilizer when OM was negligible allowed the plant to outcompete decomposing microbes for N, possibly leading to selection for microbes that primarily feed on exudates, which resulted in retarded litter decomposition rates. In conclusion, as adding inorganic fertilizer stimulated plant and root growth more than adding the equivalent nutrients in LOF, particularly in growth media with a high OM content, it is better to add inorganic nutrients than LOF to stimulate OM breakdown when plants are present. [ABSTRACT FROM AUTHOR]

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]

Anthropogenic fires pose a serious threat to many terrestrial ecosystems because they can cause loss of biodiversity and carbon stocks in the biosphere. Specifically, wildfires impacting natural conservation areas such as European Natura 2000 sites (N2K) are of particular concern. The main study objective was to evaluate the long-term effects of wildfires on the organic layer and some physical, chemical and biological properties of the underlying soil mineral layer, linked to soil quality. Here, we studied two coastal Mediterranean Aleppo pine stands within an N2K site differing for the fires' years of occurrence, the time between fires (TBF) and the time since last fire (TSLF) throughout 24 years. Furthermore, in each stand, differences in fire frequency (FF) were considered by selecting three sites—double-fire, single-fire and control (unburnt). Our results show the absence of the O-layer in double-fire sites, indicating a loss of this organic carbon (if compared to control) pool of 204 g m−2 in R2F and 139 g m−2 in M2F. Despite this loss being offset by the Corg increase in soil mineral layer, the disappearance of O-layer may compromise the ecosystem services provided by soil. In each stand, long-term fire effects were evident at both single-fire and double-fire sites for some chemical as well as biological soil properties and depended on TSLF. Increased rates of nitrogen mineralization and nitrification were found at all burned sites, persisting up to 24 years post-fire. Soil quality indicators data highlighted the recovery handicap of the microbial community within the considered period. Since our outcomes showed wildfires enduring consequences, mainly relating to TSLF and FF, on different organic and mineral soil properties, we advocate employing prompt strategies to mitigate recurring fires. [ABSTRACT FROM AUTHOR]

Bcakground: Soil respiration (Rs), as the second largest CO2 emissions of terrestrial ecosystems, is sensitive to disturbance and consequent environmental changes. Mowing is strategically implemented as an management approach and has the potential to influence carbon cycling in meadow steppes. However, it remains unclear how and why Rs and its heterotrophic (Rh) and autotrophic (Ra) components respond to consecutive mowing and associated ecological consequences. Here, we conducted a field mowing experiment in a meadow steppe in 2018 and monitored Rs, Rh, and Ra from 2019 to 2022. Results: We observed a significant reduction in Rs by 4.8% across four years, primarily attributed to a decrease in Rh. This decline in Rs intensified over time, indicating an accumulative effect of mowing. In addition, mowing induced an generally increasing Ra/Rs ratio over the experimental years with a simultaneous increase in the ratio of belowground to aboveground biomass (BGB/AGB). Furthermore, structural equation modeling results revealed that the decline in Rs was largely ascribed to reduced microbial biomass carbon (MBC) under mowing, while the increased Ra/Rs was primarily explained by the enhanced BGB/AGB. Partial regression analysis suggested that the biotic factor of microbial biomass dominated changes in soil respiration induced by mowing rather than abiotic soil temperature. Conclusions: Our findings showed that consecutive mowing decreased Rs and raised Ra/Rs in meadow steppe by decreasing plant biomass and altering the proportion of biomass allocation. This observed decline in Rs would help to reduce CO2 concentration in atmosphere as well as alleviate global warming. However, considering the concurrent lower microbial biomass, the potential positive impacts of mowing on climate and ecosystem function should be reevaluated in future grassland management practices. [ABSTRACT FROM AUTHOR]

Land abandonment promotes forest expansion into abandoned agricultural lands in Europe. This process leads to changes that affect several ecosystem services, but it is considered a low‐cost strategy to restore soil functions in past agricultural lands. Soil microbial communities play a key role in restoring functions. However, the relationship among forest expansion, microbial communities, and soil functioning is unclear. In this study, we used a Juniperus thurifera expansion gradient on abandoned agricultural lands in Alto Tajo National Park (Spain) to discover the changes elicited by the soil microbial communities and their functions along this gradient considering two microhabitats, under the canopy and open areas. Specifically, our objectives were (i) to analyse how soil properties (organic matter and pH), microbial communities (using PLFAs‐NFLAs) and enzymatic activities (related to C, N and P cycling) varied along the forest expansion gradient and between microhabitats and (ii) to decipher the pathways by which soil properties control the carbon and nutrient cycling in soils. The forest expansion gradient had a direct negative effect on phosphatase activity. The microhabitat showed a positive direct effect on organic matter content, pH, actinomycetes and arbuscular mycorrhizal fungi biomass and on soil C and P cycling. Moreover, the biomass of gram‐positive bacteria determined the biomass of other microbial groups. Synthesis and Applications: Though its effectiveness is variable, passive restoration can be more effective than active restoration. Our research indicates that passive tree colonisation of past agricultural land is enough to achieve soil functionality similar to a mature forest for most variables studied. However, some variables would need more time to reach mature forest levels, such as total microbial biomass and organic matter content. Therefore, to support ecosystem recovery, the management of this applied forest ecology strategy requires continuous monitoring of newly established trees and soil to elucidate the time needed to achieve mature soil properties. [ABSTRACT FROM AUTHOR]

Background Aim Methods Results Conclusions Tropical ecosystem functioning is influenced by seasonal fluctuations in precipitation, but the impact on soil nutrient cycling and microbial stoichiometry is not fully understood.This study investigates the magnitude of intra‐annual fluctuations in nutrient availability and microbial biomass in a tropical forest soil by examining carbon (C), nitrogen (N), and phosphorus (P) pools.We analyzed the total, extractable, and microbial C, N, and P contents and their stoichiometry in Terra Firme Ferralsols, representative for the central Amazon basin.We observed intra‐annual variations in resource availability, particularly between wet and dry seasons. Despite relatively stable total C, N, and P stocks throughout the year, we observed a decrease in extractable organic C and available (Olsen) P and an increase in extractable N in the dry season compared to the wet season. Microbial biomass pools and stoichiometry also varied across sampling dates and soil depths: relative to microbial‐C and ‐N, microbial‐P decreased in both wet and dry season and increased in the transition from wet to dry season.Our research highlights intra‐annual variation in nutrient pools, particularly dynamic microbial carbon and nutrient fractions, in weathered tropical forest soils. [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]

Grassland ecosystems have evolved alongside fire, a fundamental element that shapes and sustains their ecological balance. Recent research indicates that carbon produced during pyrogenic events in fire-dependent ecosystems may occur in more recalcitrant forms within deeper soil horizons. Notably, refractory organic carbon (ROC) and black carbon (BC) fractions are globally recognised as highly stable components of soil carbon. Here, we examined the impact of prescribed fires on the accumulation of ROC and BC fractions within South African mesic grassland soils. Our findings revealed that while BC remains stable in the soil, exhibiting consistent levels across soil horizons, increased fire frequency led to breakdown of BC in the soil. Greater BC quantities were observed in burn exclusion and prescribed burns with a greater burn interval, suggested as primarily driven by a decline in soil pH. There were no significant differences in ROC within the burn treatments, but there was a notable decrease in ROC with increasing depth increments below 5 cm. The observed trend of ROC accumulation in the top layer of soil, influenced by [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]

Background Aims Methods Results Conclusion Incorporation of cover crop (cc) shoot and root biomass can have different effects on nitrogen (N) dynamics and the transformation of soil‐derived N and cc N.The objective was to determine the effects of different ccs, cc compartments (roots and shoots), and pretreatment of cc biomass (fresh vs. dried) on mineralization processes and on the transformation of soil and cc N following incorporation into a silty loam soil.Soil columns with incorporated 15N‐labeled root and shoot biomass of two cc species (winter rye and oil radish) and different pretreatments (dried and fresh) were incubated for 70 days at a constant temperature and soil moisture (8°C, 40% water‐filled pore space). Carbon and N transformation dynamics were determined repeatedly, distinguishing between N originating from cc biomass and from soil.Net CO2 emission was related to the amount of soluble cell components added with ccs. Net N mineralization was negatively related to the C:N ratio of cc biomass. The incorporation of dried cc biomass caused higher initial soil respiration and N immobilization than fresh biomass. All treatments with cc incorporation showed increased N2O emission. Emitted N2O‐N consisted mainly of cc N (55%–57%) in treatments with fresh shoot biomass, whereas soil N was the main source of N2O (75%) in the treatment with fresh oil radish roots. Recovery of cc 15N was affected by crop compartment and pretreatment. At the end of the incubation, it was 17.5%–42.3% in soil NO3−, 0.1%–8.1% in microbial biomass N, and less than 0.23% of cc N was found in cumulative N2O emission.The incorporation of cc roots and shoots had different effects on N mobilization and immobilization processes and on the partitioning of cc N. These processes can be influenced significantly by pretreatment of the added plant biomass (dried vs. fresh). [ABSTRACT FROM AUTHOR]

Skid trails are a major management‐induced disturbance in temperate forest ecosystems with considerable impact on soil ecological processes that are so far poorly understood. In German forests, skid trails comprise 10%–20% of the forest area that is potentially affected by soil compaction through heavy machinery. We systematically investigated the influence of skid trails on physical, chemical and microbiological soil parameters at 84 paired plots across four Central European forest types.In low mountain forests with steeper topography, skid trails had more drastic effects than in lowland forests. Skid trails in low mountain areas showed a decrease in the C to N ratio of microbial biomass (MBC/MBN), as well as increased microbial (MBC/SOC) and enzyme activities leading to faster carbon turnover (lower C/N, EOC/EN) and increased CO2 losses (CO2/SOC) from the soil.The overall effects of the skid trails in lowland forests were small. On base‐poor soils, we found an increase in the MBC/MBN ratio, while skid trails in base‐rich lowland soils showed a reduction in CO2/SOC, suggesting a proportional increase in soil carbon storage.Regardless of region‐specific effects, the relative increase in the bulk density of the fine soil was identified as a 'golden trait' that determined the effects of skid trails on many soil parameters, as shown by negative correlations with SOC, N, MBC, MBN, MBP, MBC/SOC and CO2/SOC and positive ones with the activities of certain hydrolytic enzymes.Synthesis and applications: Our data clearly showed that carbon conversion processes and soil respiration leading to significant carbon and nutrient losses increased significantly on skid trails in low mountain regions with relatively steep slopes, which was in sharp contrast to lowland sites. The strong context dependence of our findings suggests that the mapping of soil conditions in terms of slope, substrate and moisture with high spatial resolution is mandatory to assess the vulnerability of sites to soil compaction by heavy machinery. Based on such vulnerability analysis, negative impacts can be minimised through the designation of permanently fixed skid trails, technical adaptation of vehicles (e.g. wide base tyres) as well as careful planning and timing of management operations that should be restricted to dry weather and soil moisture conditions or periods of frost. [ABSTRACT FROM AUTHOR]

Legume-grass mixtures are often used to increase forage yield and soil fertility in managed grasslands, but it remains unclear whether these benefits could be further improved by utilizing optimal legume-grass seeding ratios and phosphorus (P) fertilization. Here, we conducted a 5-year field experiment across 3 sites to investigate the effects of legume-grass seeding ratio and P fertilization on forage yield and soil quality. This experiment included mixtures comprised of two legume species and two grass species at five legume-grass ratios (3:7, 4:6, 5:5, 6:4, and 7:3), and monoculture of each species. P fertilizer was applied at the rate of 0, 9, 18, or 27 kg P ha-1 year-1. Plant diversity effects, e.g., complementarity and selection effects, were assessed by comparing yield of mixtures with monocultures. Our results show that a legume-grass mixture with a seeding ratio of 3:7 under moderate P fertilization resulted in the highest forage yield among all monocultures and mixtures, for each of the three sites, with persistent and consistent transgressive overyielding. Notably, greater soil organic matter, total nitrogen, enzymatic activity, and microbial biomass were observed with the legume-grass ratio of 3:7, compared to monocultures or other seeding ratios. Structural equation modeling indicated that the legume-grass ratio of 3:7 achieved highest yield through directly improving complementarity effect, and indirectly promoting selection effects because of increased fungal biomass. P fertilization directly enhanced soil nutrient and enzymatic activities, and further improved complementarity effect, resulting in high forage yield and soil quality. These results indicate that forage diversification practices with low legume-grass seeding ratios and moderate P fertilization can simultaneously benefit forage production and soil quality in managed grasslands. Overall, our study suggests that low legume seeding proportion in legume-grass mixtures combined with moderate nutrient management is a useful strategy for sustainable and highly productive managed grasslands. [ABSTRACT FROM AUTHOR]

Abstract 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. Graphical Abstract

Abstract Bcakground Soil respiration (Rs), as the second largest CO2 emissions of terrestrial ecosystems, is sensitive to disturbance and consequent environmental changes. Mowing is strategically implemented as an management approach and has the potential to influence carbon cycling in meadow steppes. However, it remains unclear how and why Rs and its heterotrophic (Rh) and autotrophic (Ra) components respond to consecutive mowing and associated ecological consequences. Here, we conducted a field mowing experiment in a meadow steppe in 2018 and monitored Rs, Rh, and Ra from 2019 to 2022. Results We observed a significant reduction in Rs by 4.8% across four years, primarily attributed to a decrease in Rh. This decline in Rs intensified over time, indicating an accumulative effect of mowing. In addition, mowing induced an generally increasing Ra/Rs ratio over the experimental years with a simultaneous increase in the ratio of belowground to aboveground biomass (BGB/AGB). Furthermore, structural equation modeling results revealed that the decline in Rs was largely ascribed to reduced microbial biomass carbon (MBC) under mowing, while the increased Ra/Rs was primarily explained by the enhanced BGB/AGB. Partial regression analysis suggested that the biotic factor of microbial biomass dominated changes in soil respiration induced by mowing rather than abiotic soil temperature. Conclusions Our findings showed that consecutive mowing decreased Rs and raised Ra/Rs in meadow steppe by decreasing plant biomass and altering the proportion of biomass allocation. This observed decline in Rs would help to reduce CO2 concentration in atmosphere as well as alleviate global warming. However, considering the concurrent lower microbial biomass, the potential positive impacts of mowing on climate and ecosystem function should be reevaluated in future grassland management practices.

Adding manure to croplands restores carbon and nutrients in depleted soils, while addressing a waste disposal need. This practice depends on the abundance and activity of microbial communities to break down manure inputs, which provide carbon for microbial growth and release nutrients for plant and microbial uptake. In a 2-year field study, we measured changes to soil physicochemical properties and microbial community composition in a conventional rotation of summer sileage corn and winter wheat. Three ratios of manure to mineral N fertilizer were used: all manure (100% of plant N from manure), mixed (50% plant N from by manure and 50% from mineral fertilizer), and all mineral (100% plant N from mineral fertilizer). Yields of corn and wheat were similar across treatments. Soil microbial community dissimilarity increased with higher ratios of application, suggesting a dose-dependent relationship between manure application and microbial community composition. Both microbial biomass and dissolved organic carbon showed the greatest response immediately following manure application, then decreased until the next application. The Shannon index increased shortly after manure application, with the largest increase observed in soils receiving manure input. Many of the taxa that increased in relative abundance following manure application were specifically taxa known to be present in manure and not common or present in soil before manure application. Microbial community changes following manure application were transitory, indicating that without continual inputs of resources, these alterations are not maintained. This was in contrast to microbial biomass which slowly increased in size over the 2-year study period. Better understanding of how manure interacts with microbial communities will help in developing better nutrient management practices and help reduce our reliance on mineral fertilizers.

Extended Abstract Background: The spatial patterns of trees, as the main components of a forest ecosystem, depend on their internal characteristics, interspecific relationships, and external environmental and habitat characteristics. The tree species that make up the forest types are among the major factors influencing soil characteristics through the production of litterfall, and they play an essential role in the quantity and quality of soil organic matter and the release of soil nutrients. Organic matter is one of the important parts of the soil, which includes tissue remains of plants and animals, their undecomposed to partially decomposed components, and dead microorganisms. The presence of organic matter, in addition to indicating the soil fertility and quality, is considered a suitable indicator for soil fertility, resulting from the interaction of physical, chemical, and biological processes. By improving soil granulation conditions, organic matter improves soil porosity and permeability; therefore, it has an important role in the stability of the ecosystem. For this reason, examining its various aspects is one of the main needs and the basis of studies on soil quality, carbon cycles, and climate change. Since there is very little information about the organic matter that can be extracted with hot water as a qualitative indicator of soil organic matter in forests, the need to pay attention to better understand the effect of different vegetation types on the soil leads to a more accurate prediction of the effect of species on ecosystems and their optimal management for managers and foresters. The present study investigates soil organic carbon and nitrogen with hot and cold water extraction methods as an indicator of soil material changes in two pure (Quercus infectoria) and mixed (Quercus libani- Quercus infectoria) types of North Zagros forests (Armardeh Baneh). Methods: Different forest types were determined using the opinions of forestry experts and statistics in the study area. The forestry characteristics were measured with five random 400 m2 sample plots in each type. The topsoil of the studied types was collected using 10 mixed samples from a depth of 0-10 cm (after removing the litterfall layer). After transporting the soil samples to the laboratory with plastic bags, the soil samples were passed through a 2 mm sieve and divided into two parts. A part of the sample was immediately exposed to 4 °C to measure the microbial mass of carbon and nitrogen, and a part of the sample was placed in the open air to measure organic carbon and total nitrogen. After measuring the studied variables, the statistical comparison of the average variables in forest types was evaluated using the independent samples t-test, analysis of variance, and their correlations with Pearson's correlation coefficient. Results: The contents of soil organic carbon and total nitrogen in the pure Q. infectoria and Q. libani-Q. infectoria types did not show significant differences. Although the amounts of hot and cold water extractable carbon and nitrogen, the microbial carbon, and nitrogen biomass were higher in Q. libani-Q. infectoria types, this difference was not significant, except for hot-water extractable carbon. There was a significant correlation between hot-water extractable carbon, microbial biomass of carbon, and cold-water extractable carbon. A significant correlation was also observed between hot-water extractable nitrogen and microbial nitrogen and carbon. Finally, there was a significant correlation between soil nitrogen with microbial biomass carbon and cold-water extractable nitrogen, but the correlation coefficient was lower than that of soil organic carbon with microbial biomass carbon and cold-water extractable carbon. Conclusion: There is an interaction between trees and soil. The growth and production of trees are related to the soil characteristics; on the other hand, the trees with their leaves and unique characteristics affect the understory soil. Based on the study outcomes, it can be concluded that extractable organic matter with hot water can be used as a sensitive indicator of changes in organic matter quality in forest soils.

Abstract Fertilizers application are widely used to get a higher yield in agricultural fields. Nutrient management can be improved by cultivating leguminous species in order to obtain a better understanding of the mechanisms that increase the amount of available phosphorus (P) and potassium (K) through fertilizer treatments. A pot experiment was conducted to identify the leguminous species (i.e., chickpea and pea) under various fertilizer treatments. Experimental design is as follows: T0 (control: no fertilizer was applied), T1: P applied at the level of (90 kg ha−1), T2: (K applied at the level of 90 kg ha−1), and T3: (PK applied both at 90 kg ha−1). All fertilizer treatments significantly (p

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]

Microorganisms help govern soil organic carbon (SOC) turnover and accumulation. Whilst it is increasingly clear that microbial necromass is a precursor of SOC formation, the relationship between living microorganisms, necromass turnover and SOC persistence remains elusive. In this study, we used phospholipid fatty acids and amino sugars to quantify living versus dead microbial carbon concentrations and evaluated the utility of each pool as an indicator of SOC persistence across a range of climates (low‐, mid‐ and high‐latitude sites) and ecotypes (old‐growth forests vs. managed croplands). We found that microbial necromass was higher in forest than in cropland soils and was positively correlated with soil moisture, SOC and total nitrogen (TN). However, the flow of microbial biomass into necromass and SOC was decoupled in forest sites, likely because the high soil SOC/TN ratio accelerated necromass turnover and recycling by living microorganisms. In contrast, microbial biomass and necromass pools were tightly coupled in croplands and influenced by multiple environmental and biological factors (e.g., necromass concentrations exhibited greater variability in soils with more bacteria than fungi, and those with more gram‐positive than gram‐negative taxa). Contrasting our expectations, the proportion of microbially‐derived necromass in SOC was decoupled from soil properties and microbial biomass in both ecotypes. Whilst SOC and pH appear to be universal drivers of necromass cycling, feedbacks between living biomass, necromass and SOC are shaped by local factors. Our results contribute to ecological theory by highlighting the environmental and biological factors underpinning SOC formation and turnover that can be used to inform land‐management practices that optimize below‐ground carbon sequestration. [ABSTRACT FROM AUTHOR]

Anthropogenic activities have raised nitrogen (N) input worldwide with profound implications for soil carbon (C) cycling in ecosystems. The specific impacts of N input on soil organic matter (SOM) pools differing in microbial availability remain debatable. For the first time, we used a much‐improved approach by effectively combining the 13C natural abundance in SOM with 21 years of C3–C4 vegetation conversion and long‐term incubation. This allows to distinguish the impact of N input on SOM pools with various turnover times. We found that N input reduced the mineralization of all SOM pools, with labile pools having greater sensitivity to N than stable ones. The suppression in SOM mineralization was notably higher in the very labile pool (18%–52%) than the labile and stable (11%–47%) and the very stable pool (3%–21%) compared to that in the unfertilized control soil. The very labile C pool made a strong contribution (up to 60%) to total CO2 release and also contributed to 74%–96% of suppressed CO2 with N input. This suppression of SOM mineralization by N was initially attributed to the decreased microbial biomass and soil functions. Over the long‐term, the shift in bacterial community toward Proteobacteria and reduction in functional genes for labile C degradation were the primary drivers. In conclusion, the higher the availability of the SOM pools, the stronger the suppression of their mineralization by N input. Labile SOM pools are highly sensitive to N availability and may hold a greater potential for C sequestration under N input at global scale. [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]

Interest in improving the long-term sustainability of agricultural production systems has focused on identifying management practices that promote soil health. No tillage, cover cropping, and amending soils with broiler (Gallus gallus domesticus L.) litter are commonly adopted conservation practices that have been shown to improve soil fertility and crop yield. However, the overall influence of these conservation practices on soil health in the southeastern US are not well understood. Thus, a study was conducted to evaluate the influence of tillage, broiler litter (BL) applications, and cropping systems on soil biochemical properties. Soils were collected from field research plots under long-term management (>than 25 years of tillage, 15 years of broiler litter application, and 15 years of cropping system). Soil microbial biomass, C, N, and P, amidohydrolases, and dissolved organic matter (DOM) were evaluated as indicators of soil health. Adopting tillage and BL into the agricultural management system modified the biochemical parameters of the soils evaluated. Most of these modifications occurred in the 0–5 cm depth. Higher microbial biomass carbon (MBC; 85%) and nitrogen (MBN; 10%) and enzyme activities of asparaginase (65%) and glutaminase (70%) were observed in the 0–5 cm depth under no tillage (NT) compared to conventional tillage (CT), indicating greater biological activities were established in these soil ecosystems. Broiler litter applications increased microbial biomass N and activities of asparaginase and glutaminase in both soil depths. In addition, microbial biomass phosphorus (MBP) was increased following BL application in the 0–5 cm depth. The results suggest that long-term management of NT and BL additions can improve the health of eroded southeastern US soils by altering the soil biochemical parameters. [ABSTRACT FROM AUTHOR]

Background: Cowpea (Vigna unguiculata L.) an important and commonly grown kharif pulse crop in India for vegetable, grain, forage and green manuring. Considering the adverse effects of chemical fertilizers, bio-inoculants should be encouraged as natural nutrient source. Methods: Three indigenous bio-inoculants viz., Rhizobium sp., Bacillus megaterium and Glomus mosseae were evaluated in a field experiment which was conducted during kharif season 2020 to study the influence of bioinoculants on growth and yield of cowpea. The experiment was laid out in randomized block design (RCBD) with ten treatments replicated thrice. Result: The application of microbial consortia significantly influenced the number of pods bearing branches, number of nodules, fresh weight of nodules, chlorophyll content, plant nitrogen and phosphorus content and microbial activities in the cowpea rhizosphere. The present study concluded that combined application of bio-inoculants (Rhizobium, PSB, AM fungi) can save 25 per cent of recommended dose of fertilizer by sustaining the crop yield and improving the soil health. [ABSTRACT FROM AUTHOR]

Background: Floodplains play an important role in the global carbon (C) cycle, particularly due to their large soil organic carbon (SOC) storage potential. However, a heterogeneous microrelief and anthropogenic landscape modifications complicate the understanding of stabilization processes of SOC in floodplains. Aim: Determining the predominant drivers for SOC stabilization in Elbe River floodplain soils. Methods: We measured SOC density fractions, microbial biomass, and mineralization characteristics in top‐ and subsoils of eight floodplain sites of the lower middle Elbe River. Results: The heavy fraction (HF) was the most important SOC pool, with a contribution of >64% at both depth intervals. With soil depth, HF pool size increased and the occluded light fraction (oLF) decreased, whereas the free LF (fLF) stayed the same. The contribution of the HF to SOC was positively related to fine texture (R2 = 0.64). Mineralizable C was negatively related to fine texture at both depth intervals. Both results suggest a positive effect of fine texture on SOC stabilization. The metabolic quotient was related to the amount of available SOC in the topsoil, but no relation was found in the subsoil. However, in top‐ and subsoil, the mineralization rate constant was positively related to the C/N ratios of the fLF and the oLF, indicating that the quality of fresh plant litter is an important energy source for microbial mineralization. Conclusion: Sedimentation of fine‐textured material is the most important driver for SOC stabilization rather than fresh plant litter input. Thus, SOC stabilization strongly depends on relief, flooding, and sedimentation. [ABSTRACT FROM AUTHOR]

Heavy-metal contamination in agricultural soil, particularly of cadmium (Cd), poses serious threats to soil biodiversity, rice production, and food safety. Soil microbes improve soil fertility by regulating soil organic matter production, plant nutrient accumulation, and pollutant transformation. Addressing the impact of Cd toxicity on soil fungal community composition, soil health, and rice yield is urgently required for sustainable rice production. Vermicompost (VC) is an organic fertilizer that alleviates the toxic effects of Cd on soil microbial biodiversity and functionality and improves crop productivity sustainably. In the present study, we examined the effects of different doses of VC (i.e., 0, 3, and 6 tons ha−1) and levels of Cd stress (i.e., 0 and 25 mg Cd kg−1) on soil biochemical attributes, soil fungal community composition, and fragrant-rice grain yield. The results showed that the Cd toxicity significantly reduced soil fertility, eukaryotic microbial community composition and rice grain yield. However, the VC addition alleviated the Cd toxicity and significantly improved the soil fungal community; additionally, it enhanced the relative abundance of Ascomycota, Chlorophyta, Ciliophora, Basidiomycota, and Glomeromycta in Cd-contaminated soils. Moreover, the VC addition enhanced the soil's chemical attributes, including soil pH, soil organic carbon (SOC), available nitrogen (AN), total nitrogen (TN), and microbial biomass C and N, compared to non-VC treated soil under Cd toxicity conditions. Similarly, the VC application significantly increased rice grain yield and decreased the Cd uptake in rice. One possible explanation for the reduced Cd uptake in plants is that VC amendments influence the soil's biological properties, which ultimately reduces soil Cd bioavailability and subsequently influences the Cd uptake and accumulation in rice plants. RDA analysis determined that the leading fungal species were highly related to soil environmental attributes and microbial biomass C and N production. However, the relative abundance levels of Ascomycota, Basidiomycota, and Glomeromycta were strongly associated with soil environmental variables. Thus, the outcomes of this study reveal that the use of VC in Cd-contaminated soils could be useful for sustainable rice production and safe utilization of Cd-polluted soil. [ABSTRACT FROM AUTHOR]

This study evaluated the chemical and microbiological soil attributes in a silvopastoral system compared to well-managed pasture, degraded pasture, and Cerrado vegetation in Brazil. A randomized design with four replications was employed to collect soil samples at seven depths. These samples were analyzed for carbon (C), nitrogen (N), pH, phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), and cation exchange capacity (CEC). Soil microbial attributes were also evaluated at three depths during the dry and wet seasons. Carbon stocks in the evaluated systems varied (0–100 cm), with the highest stocks found in well-managed pasture (MP) (129.5 Mg C ha−1), followed by the silvopastoral system (SPS) (106.6 Mg C ha−1), and the lowest values in native vegetation (NV) (84.8 Mg C ha−1) and degraded pasture (DP) (63.4 Mg C ha−1). Higher pH and base sum were observed in MP. Soil microbial biomass (Cmic) did not differ between treatments during the wet season but was generally higher in MP and lower in DP during the dry season. MP effectively regulated the chemical and biological quality of the soil. The SPS demonstrated that it is possible to combine the cultivation of trees and pastures in the same area, contributing to the improvement of the chemical and biological attributes of the soil in the Brazilian Cerrado. [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]

El Niño-induced drought, which is intensified by climate change, can have huge impacts on soil microbial biomass and plant productivity in tropical forests. We tested whether drought-induced turnover of soil microbial biomass can be a potential source of phosphorus (P), the limiting nutrient, for the reproduction of tropical forest trees (mast fruiting). We measured the seasonal variations in soil microbial biomass P and soil solution P concentrations including the periods before and after drought in a dipterocarp forest in Indonesia. Drought resulted in a decrease in soil microbial biomass C, N, and P, followed by a recovery after re-wetting. There was a sharp peak of soil solution P concentrations during the drought. The significant difference between soil microbial biomass P before and after drought amounted to 2.0 kg P ha−1. The potential P release from microbial turnover is not negligible compared to the additional P demand for fruit production (1.0 kg P ha−1) as well as the annual demand for litter production (2.5 kg P ha−1 year−1). In addition to the accumulation of nutrients for several non-fruiting years and their re-distribution in tree biomass, drought-induced microbial turnover can be nutrient subsidies for dipterocarp reproduction in highly-weathered soils. [ABSTRACT FROM AUTHOR]

Terrestrial organic matter subsidizes aquatic food webs and plays an important role in carbon cycling in lake ecosystems, where it is decomposed mainly by microbes. However, the contribution of terrestrial and aquatic microbiomes on terrestrial carbon cycling and their effects on the biochemical fate of carbon has remained understudied. Therefore, we explored the microbial carbon utilization of three chemically differing leaf species in lake water in microcosms and quantified the biochemical endpoints of leaf carbon in CO2, CH4, and microbial biomass. Additionally, we identified microbial taxa responsible for leaf carbon recycling and studied the role of epiphytic and endophytic leaf microbiomes in microbial community succession in lake water. Microbially utilized leaf carbon was mainly respired (82.7 ± 1.4%), whereas a small proportion (17.1 ± 1.4%) was assimilated into biomass. Carbon from nitrogen‐rich alder leaves was taken up at the fastest rate, whereas birch leaf addition produced the highest concentrations of CH4, suggesting that leaf chemistry affects the decomposition rate and biochemical fate of carbon. In particular, terrestrial bacteria shaped the succession of aquatic bacterial communities. The addition of leaves resulted in the equal contribution of epiphytic and endophytic bacteria in the lake water, whereas epiphytic fungi dominated the fungal community structure. Our results suggest that terrestrial bacteria originating from terrestrial leaves influence the microbiome succession in lake ecosystems and play a key role in linking terrestrial carbon to an aquatic food web and determining the quality of carbon emissions that are released into the atmosphere. [ABSTRACT FROM AUTHOR]

Cover cropping is a soil restorative strategy that can save degraded soils and offer additional benefits relative to the traditional fallow-based practice in semi-arid cropping systems. This study aimed to (i) quantify the above (shoot)- and belowground (root) biomass production, nutritive value, and tissue carbon and nitrogen concentrations from different annual cool-season cover crop systems, and (ii) determine their effects on soil organic carbon, total nitrogen, soil respiration, and soil microbial population biomass in a semi-arid environment. Treatments used were monocultures of annual ryegrass (Lolium multiflorum Lam.), oat (Avena sativa L.), faba bean (Vicia faba L.), yellow sweetclover [Melilotus officinalis (L.) Lam], winter pea (Pisum sativum L.), two three-species mixtures (Mix 1: annual ryegrass + faba bean + yellow sweetclover and Mix 2: Oat + faba bean + winter pea), and a fallow laid out in a randomized complete block design with three replications. Averaged across years, Mix 2 produced greater shoot biomass (9714 kg DM ha−1; SE = 699) than all other cover crop systems except, the monoculture of oat (7970 kg DM ha−1; SE = 699). The plant tissue C/N ratio of the mixtures and monoculture legumes was mostly similar (range = 19.4–29.1). Overall, legumes produced superior relative feed value (RFV; 112–161) compared to grass monocultures and mixtures (RFV; 80–95). Soil gram-negative bacteria biomass was greatest under the yellow sweetclover monoculture. Based on the results of this study, the mixed cover crop systems (Mix 1 and Mix 2) offered a better chance of fulfilling the dual role of soil health improvement and feed quality for livestock in this semi-arid environment.

Soil organic carbon (SOC) loss from intensive agriculture represents a major global concern. Consequently, strategies to improve soil management to mitigate or abate SOC losses and enhance carbon (C) sequestration are urgently needed. Nutrient availability, especially nitrogen (N) and phosphorus (P), regulates soil C cycling and storage. While N effects are well studied, less is known about how soil P status and different fertilizer types affects SOC dynamics. This laboratory incubation assessed how two common P fertilizers, diammonium phosphate (DAP) and single superphosphate (SSP), affected microbial activity and C immobilization in the zone of soil directly around the fertilizer granule (prillosphere) across three contrasting agricultural soils (Inceptisol, Vertisol, Alfisol). Soils were amended with DAP or SSP granules and C turnover assessed with 14C-labeled glycine, malic acid or glucose, alongside unfertilized controls. After three weeks, soil pH, electrical conductivity (EC), Olsen-P and microbial C use efficiency (CUE) were measured. DAP increased pH in the Inceptisol (acidic soil), while SSP decreased pH in all soils. Both fertilizers increased EC and Olsen-P, but SSP enhanced Olsen-P more than DAP. Cumulative 14CO2 emissions were 19–20 % higher with P fertilizers compared to the control, with DAP stimulating faster initial C mineralization rates than SSP, except in the Alfisol. P addition reduced microbial CUE by 23–34 % across all soils and substrates versus the unfertilized control. We ascribe this reduction in CUE to an alleviation of nutrient limitation or a fertilizer-induced osmotic stress. The co-addition of N either in DAP or glycine did not alter the P-induced CUE response suggesting that P was more important than N in regulating microbial CUE in these soils. We conclude that P fertilization increased short-term C turnover and may lead to reduced C storage in soil, however, further long-term (>1 year) research is needed to identify optimum P management strategies to minimize C losses in agricultural soils.

Background Sequestering carbon dioxide (CO2) in agricultural soils promises climate change mitigation as well as sustainable ecosystem services. In order to stabilize crop residues as soil carbon (C), addition of mineral nutrients in excess to crop needs is suggested as an inevitable practice. However, the effect of two macronutrients i.e., nitrogen (N) & phosphorus (P), on C cycling has been found contradictory. Mineral N usually decreases whereas mineral P increases the soil organic C (SOC) mineralization and microbial biomass. How the addition of these macronutrients in inorganic form to an organic-matter poor soil affect C cycling remains to be investigated. Methods To reconcile this contradiction, we tested the effect of mineral N (120 kg N ha−1) and/or P (60 kg N ha−1) in presence or absence of maize litter (1 g C kg−1 soil) on C cycling in an organic-matter poor soil (0.87% SOC) in a laboratory incubation. Soil respiration was measured periodically during the incubation whereas various soil variables were measured at the end of the incubation. Results Contrary to literature, P addition stimulated soil C mineralization very briefly at start of incubation period and released similar total cumulative CO2-C as in control soil. We attributed this to low organic C content of the soil as P addition could desorb very low amounts of labile C for microbial use. Adding N with litter built up the largest microbial biomass (144% higher) without inducing any further increase in CO2-C release compared to litter only addition. However, adding P with litter did not induce any increase in microbial biomass. Co-application of inorganic N and P significantly increased C mineralization in presence (19% with respect to only litter amended) as well as absence (41% with respect to control soil) of litter. Overall, our study indicates that the combined application of inorganic N and P stabilizes added organic matter while depletes the already unamended soil.

The summarized data on the content of organic carbon (Corg) in the subtypes of gray forest soils occurring on the territory of Russia was presented. It was shown that the humus horizons of virgin light-gray, typical-gray, and dark-gray forest soils contain, on average, 2.16 ± 0.67, 2.42 ± 0.61, and 3.58 ± 0.95% Сorg, respectively, while the plowing layers of arable soils contain 1.36 ± 0.40, 1.71 ± 0.40, and 2.84 ± 0.86%, respectively. Structural (particulate organic matter 0.05–2 mm in size, CPOM, and mineral-associated organic matter

ABSTRACTMineral oil-derived lubricants, extracted from fossil fuels, account for approximately 90% of the lubricant market. A large proportion of these lubricants end up in the environment through usage, spillage, and disposal, leading to contamination of aquatic systems, ecosystems, and agricultural lands. To address this, new regulations were released (e.g. Vessel General Permit 2013) to promote the use of Environmentally Acceptable Lubricants (EALs) over conventional, toxic, non-biodegradable mineral oils. Today, the range of EAL is limited, particularly affecting the maritime sector. Since 2013, the variety and effectiveness of EALs have improved, but further advancements and cost reductions are essential. This study focuses on developing sustainable bio-based additives from microbial processes to enhance EALs. These additives, sourced through fermentation, avoid using fossil fuels and do not require arable land, preserving water resources and food production areas. The research reveals that yeast, high in sulfur and phosphorus, and microbial oils, mainly carboxylic acids, effectively stabilize EAL formulations, reducing friction and wear in water-based lubricants. Microbial oils are superior in reducing friction, while yeast offers better wear protection. This study opens the possibility of incorporating various bio-based products into EALs, providing a sustainable, environmentally friendly option.

Global warming has contributed to shifts in precipitation patterns and increased plant productivity, resulting in a significant increase in litter input into the soils. The enhanced litter input, combined with higher levels of precipitation, may potentially affect soil microbial communities. This study aims to investigate the effects of litter input and increased precipitation on soil microbial biomass, community structure, and diversity in a temperate meadow steppe in northeastern China. Different levels of litter input (0%, +30%, +60%) and increased precipitation (0%, +15%, +30%) were applied over a three-year period (2015-2017). The results showed that litter input significantly increased the biomass of bacteria and fungi without altering their diversity, as well as the ratio of bacterial to fungal biomass. Increased precipitation did not have a notable effect on the biomass and diversity of bacteria and fungi, but it did increase the fungal-to-bacterial biomass ratio. However, when litter input and increased precipitation interacted, bacterial diversity significantly increased while the fungal-to-bacterial biomass ratio remained unchanged. These findings indicate that the projected increases in litter and precipitation would have a substantial impact on soil microbial communities. In energy-and water-limited temperate grasslands, the additional litter inputs and increased precipitation contribute to enhanced nutrient and water availability, which in turn promotes microbial growth and leads to shifts in community structure and diversity. [ABSTRACT FROM AUTHOR]

Microbial biomass, diversity of culturable bacteria and micromycetes, and the number of functional nitrogen cycle genes in the supraglacial systems of the Aldegonda and Bertil glaciers have been studied. The biomass of microorganisms varies from 2.54 to 722 µg/g substrate. It is shown for the first time that the major part (78.7–99.8%) of microbial biomass in supraglacial objects is represented by fungi rather than by prokaryotes, and the main part (70 to 90%) of the fungal biomass consists of mycelium with the length varying from 6.70 to 537.51 m/g substrate. The counts of prokaryotes vary from 2.4 × 108 to 1.95 × 109 cells/g substrate. The length of actinomycete mycelium falls into the range of 2.6–62.61 m/g substrate. The counts of culturable bacteria and actinomycetes vary from 3.3 × 104 to 1.2 × 106 CFU/g substrate and of micromycetes, from 2.2 × 101 to 1.7 × 104 CFU/g substrate. Bacteria of the genera Arthrobacter, Bacillus, Rhodococcus, Streptomyces and micromycetes of the genera Antarctomyces, Cadophora, Hyphozyma, Teberdinia and Thelebolus are dominants. The micromycetes Antarctomyces psychrotrophicus, Hyphozyma variabilis and Teberdinia hygrophila are found in Svalbard for the first time. The copy number of amoA genes in ammonium-oxidizing bacteria varies from 5.33 × 106 to 4.86 × 109/g substrate; of nitrogen fixation genes nifH, from 9.89 × 107 to 9.81 × 1010/g substrate; and denitrification genes nirK, from 4.82 × 107 to 3.34 × 1010/g substrate. These results indirectly suggest the leading role of fungi in the microbiome of the supraglacial objects in Svalbard and a considerable contribution of prokaryotes to the emission of greenhouse gases there. [ABSTRACT FROM AUTHOR]

The purpose of this research is to investigate the interactions among wheat varieties and microorganisms within rhizosphere and how conventional agriculture affects these dynamics during the growing season. Indeed, little is known about how commercial bread varieties modulate root exudates and how agrochemicals affect the microbiological processes. Therefore, this study investigated the changes in soil microbiological features such as enzyme activities (β-glucosidase, xylosidase, glucoronidase, chitinase, leucine-aminopeptidase, acid and alkaline phosphomonoesterases, inositol phosphatase, phosphodiesterase, pyrophosphatase–phosphodiesterase, arylsulphatase) and microbial biomass as a function of treatment (fungicides and plant growth regulator—PGR) and wheat varieties (Skyfall, SY Moisson, Aquilante, Bandera, Tintoretto, Antille, and Bologna) at the sowing, heading, and harvesting stage. A total of 168 samples (2 treatments × 7 varieties × 3 field replicates × 4 sub-samples taken in each plot) were collected in each period and analyzed. We found that soil microbial biomass was a sensible indicator in the fungicide/PGR application, with reduced values in treated plots at the heading. At this stage, the soil enzymatic activities were in general more expressed, confirming that the microbial processes are more proactive due to the growth of plants. Overall, the soil enzymatic activities responded differently according to the wheat varieties, highlighting specific capabilities to interact with microbes. [ABSTRACT FROM AUTHOR]

The combination of conservation tillage (non-inversion and no-till) with organic farming is rare due to weed problems. However, both practices have the potential to improve soil quality and increase soil organic C (SOC). This study investigated the changes in SOC, microbial biomass, and microbial composition during the transition from conventional to organic farming (from 2014 to 2020) in a long-term tillage trial established in 1999. Non-inversion minimum tillage to a depth of 10 cm (MT) resulted in SOC stratification, whilst conventional soil tillage with 25-cm-deep mouldboard ploughing (CT) maintained an even SOC distribution in the plough layer. After 12 years of contrasting tillage in 2011, the uppermost soil layer under MT had a 10% higher SOC content (1.6% w/w) than CT (1.45% w/w). This difference became even more pronounced after introducing organic farming in 2014. By the fall of 2020, the SOC content under MT increased to 1.94%, whilst it decreased slightly to 1.36% under CT, resulting in a 43% difference between the two systems. Conversion to organic farming increased microbial biomass under both tillage systems, whilst SOC remained unchanged in CT. Abundances of total bacterial and Crenarchaeal 16S rRNA and fungal ITS genes indicated shifts in the microbial community in response to tillage and depth. Fungal communities under MT were more responsive to organic farming than bacterial communities. The improved soil quality observed under MT supports its adoption in both organic and conventional systems, but potentially large yield losses due to increased weed cover discourage farmers from combining MT and organic farming. [ABSTRACT FROM AUTHOR]

Background: Soils under organic farming systems exhibit better quality and higher biological activity than conventional systems. Manure addition, especially coupled with reduced or no tillage, significantly enhances microbial biomass and activity by improving soil physical properties and providing carbon (C) and nitrogen (N) sources. While several studies have examined the effects of transitioning from conventional to organic farming on soil chemistry and biochemistry, limited research has explored the influence of land use variations on soil fertility within long‐term organic farming systems. Aims: Therefore, the aim of this study was to assess how three different land uses—pasture, vegetable crops, and orchard—affected soil fertility under a long‐term organic farming system. Methods: Soil samples were collected from the 0 to 15 cm layer of plots used for pasture, vegetable crops and orchard, being the latter cover cropped with legumes, and analyzed to determine chemical and biochemical soil parameters. Results: Contrary to expectations, high land use intensity (vegetable crops and orchard soils) resulted in increased soil organic C and total N, compared to low intensity (pasture). Such an increase was ascribed to farmyard manure addition that counteracted the negative impact of tillage. Consequently, microbial biomass C and activity also increased. The greatest availability of organic substrates favored bacteria, particularly gram‐positive strains, shaping the microbial community. However, despite changes of microbial biomass and of the main microbial groups, microbial activity was only slightly affected, suggesting high functional redundancy of microorganisms in long‐term organic farming soil. Conclusions: Results suggested that if land use intensification provides for organic supply, its negative impact on soil fertility may be mitigated. [ABSTRACT FROM AUTHOR]

Pinus halepensis Miller is a widespread tree species in the western Mediterranean basin, where very dense monospecific stands can be found, especially in natural regeneration after forest fires. Silvicultural thinning can reduce the competition of trees for natural resources and favour their development, although its effect depends on the habitat. The present study aims to know the effects on the soil at the physicochemical and microbiological levels after a heavy thinning in a young pine forest stand with a high stocking density. The stand is on a slope where the soil depth tends to decrease with altitude, and shows changes in its physicochemical properties between the upper and lower zones. Several soil carbon fractions (i.e., soil organic carbon (SOC), water-soluble organic carbon (WSOC), and microbial biomass carbon (MBC)), microbial activity (basal soil respiration (BSR)) and enzyme activities (acid phosphatase (AP) and urease (UA)) were analysed at specific dates over a period of about five years after a heavy thinning. The changes in organic matter content were abrupt in the slope, conditioning the observed differences. It is highlighted that the SOC and WSOC contents in the mineral soil were 2.5- and 3.5-fold significantly higher, respectively, in the upper shallow zone compared to the lower deeper zone. This was also reflected in significantly higher levels of gravimetric water content (GWC) and MBC (both about 1.4-fold higher), with higher levels of BSR and UA, and 2.5-fold significantly higher levels of AP. As a result, most of the properties studied showed no significant differences between the thinning treatment and the untreated control. Results varying between dates, with a strong dependence on climate (soil temperature and humidity) of WSOC and UA. It can be concluded that the heavy thinning applied in this short-term case study favoured the growth conditions of the pine without negatively affecting the soil properties studied. [ABSTRACT FROM AUTHOR]

In grape cultivation, incorrect water regulation will lead to significant water wastage, which in turn will change soil structure and disrupt soil nutrient cycling processes. This study aimed to investigate the effects of different water regulation treatments [by setting moderate water stress (W1), mild water stress (W2), and adequate water availability (CK)] on soil physical-chemical properties and enzyme activity in greenhouse grape during the growing season. The result showed that the W2 treatment had a negative impact on the build-up of dissolved organic carbon (DOC), nitrate nitrogen (NO3-N), and available phosphorus (AP). Throughout the reproductive period, the W1 and W2 treatments decreased the soil's microbial biomass carbon (MBC) and microbial biomass nitrogen (MBN) contents, and MBC was more vulnerable to water stress. During the growth period, the trends of urease, catalase, and sucrase activities in different soil depth were ranked as 10-20 cm > 0-10 cm > 20-40 cm. The urease activity in 0-10 cm soil was suppressed by both W1 and W2 treatments, while the invertase activity in various soil layers under W1 treatment differed substantially. The W1 treatment also reduced the catalase activity in the 20-40 cm soil layer in the grape growth season. These findings suggested that W2 treatment can conserve water and enhance microbial ecology of greenhouse grape soils. Therefore, W2 treatment was the most effective water regulation measure for local greenhouse grape cultivation. [ABSTRACT FROM AUTHOR]

Biodegradation rates and mechanical properties of poly(3-hydroxybutyrate) (PHB) composites with green algae and cyanobacteria were investigated for the first time. To the authors knowledge, the addition of microbial biomass led to the biggest observed effect on biodegradation so far. The composites with microbial biomass showed an acceleration of the biodegradation rate and a higher cumulative biodegradation within 132 days compared to PHB or the biomass alone. In order to determine the causes for the faster biodegradation, the molecular weight, the crystallinity, the water uptake, the microbial biomass composition and scanning electron microscope images were assessed. The molecular weight of the PHB in the composites was lower than that of pure PHB while the crystallinity and microbial biomass composition were the same for all samples. A direct correlation of water uptake and crystallinity with biodegradation rate could not be observed. While the degradation of molecular weight of PHB during sample preparation contributed to the improvement of biodegradation, the main reason was attributed to biostimulation by the added biomass. The resulting enhancement of the biodegradation rate appears to be unique in the field of polymer biodegradation. The tensile strength was lowered, elongation at break remained constant and Young's modulus was increased compared to pure PHB. [ABSTRACT FROM AUTHOR]

This study evaluated the changes in microbial activity in the course of time following the joint application of the herbicides S-metolachlor, foramsulfuron, and thiencarbazone-methyl to two soils (S1 and S2) under conventional tillage (CT) and non-tillage (NT) management in field conditions. The biochemical parameters of soil respiration (RES), dehydrogenase activity (DHA), microbial biomass (BIO), and the phospholipid fatty acid (PLFA) profile were determined at 1, 34, and 153 days during herbicide dissipation. In the absence of herbicides, all microbial activity was higher under NT than CT conditions, with higher or similar mean values for S1 compared to S2. A continuous decrease was detected for RES, while DHA and BIO recovered over time. In the presence of herbicides, a greater decrease in all microbial activity was detected, although the changes followed a similar trend to the one recorded without herbicides. In general, a greater decrease was observed in S1 than in S2, possibly due to the higher adsorption and/or lower bioavailability of herbicides in this soil with a higher organic carbon content. The decrease was also greater under CT conditions than under NT conditions because the herbicides can be intercepted by the mulch, with less reaching the soil. These changes involved evolution of the structure of the microbial community. [ABSTRACT FROM AUTHOR]