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Biological soil crust (BSC) constitutes a consortium of cyanobacteria, algae, lichen, mosses, and heterotrophic microorganisms, forming a miniature ecosystem within the uppermost soil layer. The biomass of different organisms forming BSC and their activity changes along with succession. Previous studies focused primarily on BSC in hyper-arid/arid regions, whereas the ecophysiology of BSC in temperate climates is still not well recognized. In order to determine changes in overall microbial activity and photosynthetic biomass in BSC at different stages of the succession of inland sandy grasslands, we analyzed dehydrogenase activity and determined the content of photosynthetic pigments. We also compared these parameters between BSC developed on the dune ridges and aeolian blowouts in the initial stage of succession. Our study revealed a significant increase in both photosynthetic biomass and overall microbial activity in BSC as the succession of inland shifting sands progresses. We found that chl a concentration in BSC could be considered a useful quantitative indicator of both the presence of photoautotrophs and the degree of soil crust development in warm-summer humid continental climates. The photosynthetic biomass was closely related to increased microbial activity in BSC, which suggests that photoautotrophs constitute a major BSC component. Dune blowouts constitute environmental niches facilitating the development of BSC, compared to dune ridges. High biomass of microorganisms in the dune blowouts may be associated with a high amount of organic material and more favorable moisture conditions. We conclude that deflation fields are key places for keeping a mosaic of habitats in the area of shifting sands and can be a reservoir of microorganisms supporting further settlement of dune slopes by BSC. [ABSTRACT FROM AUTHOR]

The forests are major resources for carbon sequestration and help to mitigate the adverse effect of atmospheric carbon and reduce global warming. The present study was conducted to estimate the carbon sequestration potential of the Quercus floribunda forests at two different aspects and three altitudes. Ten quadrates of 10 × 10 m size were laid out in each forest for the estimation of stand density, tree biomass, and soil samples were collected from each quadrate. Q. floribunda was the dominating tree at studied altitudes and aspects with the IVI values of 161.14 and 124.96 in the southern aspect and northern aspects, respectively. the highest values of above-ground biomass density (AGBD), below-ground biomass density (BGBD), total biomass density (TBD), and total carbon density (TCD) was recorded at the upper elevation (2500–2700 m) of southern and northern aspects. In the southern aspect values of AGBD (476.67 < 575.67 Mg/ha), BGBD (124.8 < 148.9 Mg/ha), TBD (601.53 < 724 Mg/ha), TCD (300.83 < 362.03 Mg/ha) were higher than northern aspect. The values of AGBD, BGBD, TBD, and TCD were reported maximum (638 Mg/ha, 163.1 Mg/ha, 800.5 Mg/ha, and 400.35 Mg/ha; respectively) in the upper elevation. Soil organic carbon (SOC), soil organic matter (SOM), and soil organic carbon stock (SOCS) decreased with increasing altitudes and depths which were found higher in the southern aspect. Bulk density (BD) and P increased with altitudes and depth however bulk density was equal (1.29 g cc-1) in both aspects whereas P was also found higher (31.43 kg/ha) in the southern aspect. Highest available nitrogen (398 kg/ha) was recorded in the northern aspect at middle altitude. The available potassium was highest in the northern aspect. At lower altitudes, available potassium ranges between 246–615 kg/ha. Soil pH was found slightly acidic in all the sites ranging from 4.91 to 5.74 in different soil depths. Dehydrogenase activity was ranged between 1.35 and 8.74 µg/g/h from lower to upper soil depth and decreased with an increase in soil depths and increased with altitudes, whereas found highest in the southern aspect. The present study suggested that tree density, tree biomass, carbon sequestration potential, and soil health in Q. floribunda forests were substantially influenced by the altitude as well as the aspect. These findings contribute valuable insights for climate change mitigation and forest management strategies in the study region.

A field experiment was executed during the Rabi season at CSKHPKV, Palampur, to evaluate the effects of different weed control and nitrogen management practices on weed control, yield, nutrient content, dehydrogenase activity and the oil content of linseed. The experiment was set up in the RBD with 3 replicates consisting of fifteen treatment combinations comprising five weed controls (viz. isoproturon 1.25 kg/ha, clodinafop propargyl + metsulfuron methyl 60+4 g/ha, clodinafop propargyl + carfentrazone ethyl 60+10 g/ha, hand weeding twice and weedy check) and three nitrogen levels (i.e., FYM 5 t/ha, 75 and 100% RDN). The soil texture at the experimental site was silty clay loam, acidic and medium in available nitrogen, phosphorus and potassium. The results showed that the use of clodinafop propargyl + metsulfuron methyl 60+4 g/ha significantly decreased the count and dry matter content of the total weeds at the maximum count and dry matter stage. However, 1.25 kg/ha isoproturon was likewise effective at significantly reducing the total weed count and was the next best at reducing the dry matter content of the total weeds. The effective control of weeds by the application of isoproturon at 1.25 kg/ha (Post.) significantly increased plant growth without any toxicity, which contributed to increased nutrient uptake and increased seed, straw and oil yields in the linseed treatment. Among the nitrogen levels, a considerably lower count and dry matter content of the total weeds were recorded in the 100% RDN plots, followed by the 75% RDN treatment. The application of 100% RDN resulted in significantly greater NPK uptake than did the other treatments, which contributed to considerably greater seed, straw and oil yields. Thus, the application of isoproturon at 1.25 kg/ha (Post.) with 100% RDN was proven to be the most effective at realizing higher seed and oil yields with better weed control in linseed plants grown under utera conditions. [ABSTRACT FROM AUTHOR]

The aim of the study was to assess the impact of plant extracts from hemp inflorescences (H10—10% and H20—20%), as well as a mixture of extracts from hemp inflorescences, sage, and tansy leaves (M10—10% and M20—20%) on phytotoxicity and selected physiological and biometric parameters of wheat seedlings, as well as the biological activity of soil in a growth chamber experiment. In all experimental combinations, a low phytotoxicity of the extracts was observed in the form of leaf tip yellowing, classified as first-degree damage or its complete absence. The plant extracts and their mixtures, except for the H20 extract, had an inhibitory effect on the development of fungal pathogens, especially Fusarium spp. The H20 extract increased the fresh and dry weight of root seedlings. The tested extracts also had a positive effect on the chlorophyll content in seedlings. The highest chlorophyll concentrations were recorded for the seedlings sprayed with the M20 extract mixture. The applied plant extracts influenced the activity of soil enzymes. The highest activity of catalase and dehydrogenases was observed after spraying seedlings with M20, while the lowest was recorded after applying H10. Of all the tested groups of soil environment compounds included in the Biolog EcoPlates test, carbohydrates and carboxylic acids were most actively utilized. Conversely, amines and amides constituted the group of compounds utilized the least frequently. The present study demonstrated the high effectiveness of plant extracts on wheat seedlings due to their biocidal action against phytopathogenic fungi and increased biological activity of the soil. This research serves as an initial phase of work, which will aim to verify the results obtained under field conditions, as well as assess the biological stability of the extracts. [ABSTRACT FROM AUTHOR]

The present study was conducted to investigate the vertical diversity of soil dehydrogenase and phosphatase activity under coconut (Cocosnucifera L.,) and arecanut (Arecacatechu L.,) plantations within four soil depths (0–30, 30–60, 60–90, and 90–120 cm) and to determine the factors controlling the distribution across the different agro-climatic zones of Karnataka. A total of 176 soil samples from 30 soil profiles were collected from coconut and arecanut plantations representing 5 different agroclimatic zones (ACZ) and three soil types (Lixisols, Сambisols, and Acrisols) and analyzed for three major soil enzymes viz. dehydrogenase (DHA), acid phosphatase (ACP) and alkaline phosphatase (ALP). The results revealed that the pooled mean of DHA activity was higher in arecanut (7.44 µg TPF g–1 h–1) than coconut (5.75 µg TPF g–1 h–1) and the same pattern has been noticed in both ACP (84.041 and 48.19 µg PnP g–1 h–1 for arecanut and coconut plantations) and ALP (63.57 and 32.14 µg PnP g–1 h–1 for arecanut and coconut plantations). The impact of climate on soil enzyme activity showed that the southern dry zone (SDZ) was high in DHA (10.5 µg TPF g–1 h–1) and ALP (77.98 µg PnP g–1 h–1) activities followed by the eastern dry zone and the lowest was noticed in the coastal zone (CZ). However, ACP activity was higher in CZ (110.24 µg PnP g–1 h–1) and lower in SDZ (33.85 µg PnP g–1 h–1). As soil depth increases enzyme activity is decreased and nearly 50% of enzyme activities are restricted within 0–30 cm soil depth. We observed that greater activity of DHA and ALP was noticed in Lixisols than in Acrisols and Cambisols, whereas higher activity of ACP was found in Acrisols. Our analysis showed that the type of plantations, climate and soil type significantly affect the distribution of enzymes in soil. [ABSTRACT FROM AUTHOR]

The European Commission's "Farm to Folk" (F2F) strategy recommends reducing fertilizers by at least 20% by 2030. In this aspect, the main goal of our study was to verify whether a 20 and even 40% reduction in nitrogen (N) fertilization rate would be sufficient to maintain soil fertility (expressed as dehydrogenase activity—DHA, humic acid substances—HA substances, E4/E6 ratio), and yields of wheat and rapeseed cultivated in strip-till technology. Two fields (10 ha each) were established for wheat and rapeseed cultivation, and soils (0–20 cm) were sampled before sowing and after harvesting. It was found that a 20% fertilization reduction does not adversely affect the biological activity expressed by DHA. Nevertheless, the reduction in nitrogen (N) fertilizer rates led to a slight decrease in the E4/E6 ratio, which could serve as a potential indicator of fertilization reduction. DHA, E4/E6 ratio and content of HA substances were also dependent on the crop. Following harvesting, both rapeseed and wheat exhibited a positive correlation between the E4/E6 ratio and the degree of fertilization rate (FR), as well as yield. [ABSTRACT FROM AUTHOR]

In order to maintain a healthy soil, organic farming (OF) and natural farming (NF) should be practiced in addition to conventional farming. In order to evaluate soil fertility and productivity, a field experiment was conducted to study the microbial populations, dehydrogenase activities and biomass carbon in rhizosphere soils of cabbage under different farming systems over two years. Generally, microbial populations are expressed as colony forming units (CFU). Significantly higher microbial populations such as bacteria (34.15 × 106 CFU g−1of soil), fungi (19.08 × 103 CFU g−1of soil), actinomycetes (20.18 × 104 CFU g−1of soil), phosphate solubilizing microorganisms (11.45 × 104 CFU g−1of soil) and nitrogen fixers (14.78 × 104 CFU g−1of soil) were observed in rhizosphere soils after harvest of cabbage in organic farming followed by natural farming treatment. Dehydrogenase activity and microbial biomass carbon were significantly higher under organic farming. Lower microbial populations, dehydrogenase activity and microbial biomass carbon were found in conventional farming practices. It is concluded that application of organic farming inputs farm yard manure (FYM) and natural farming inputs, i.e. liquid organic manure (jeevamrutha), solid organic manure (ghanajeevamrutha) enhanced the soil microflora, dehydrogenase activity and microbial biomass carbon activities when compared to the conventional farming system. [ABSTRACT FROM AUTHOR]

In comparison to mineral commercial phosphorus fertilizers, struvite is considered to be a promising P fertilizer, which – in the face of dwindling phosphate resources – may replace phosphate fertilisers in the future. The fertilising value of struvite arises from its significant phosphorus content as well as magnesium and nitrogen content, enhanced by the slow release of the components. The purpose of this study was to explore the response of the soybean cultivar Abaca to struvite fertilization in terms of the plant’s yield and chlorophyll content as well as changes in the soil’s microbiological life. A pot experiment was set up at the Pawłowice Research and Education Station, on soil low in phosphorus, and with two variable factors: different application methods of phosphorus fertilizer (band and broadcast), and two phosphorus fertilisers (superphosphate and struvite). The method of phosphorus application had a significant effect on the plant’s biometric traits, chlorophyll a content and the microbial activity of soil. Struvite fertilization caused significant changes in the chlorophyll and carotenoid content. Significantly higher content of chlorophyll a and carotenoids as well as a higher total chlorophyll content were noted under struvite fertilization. Fertilizer application techniques caused a significant effect on the chlorophyll a content. Both the application methods and the type of phosphorus fertilizer had a significant effect on microbiological activity at the two measurement dates. Total glomalins content was significantly higher only in the case of band application of phosphate fertilizers at the end of the experiment, and the dehydrogenase activity was significantly increased at the flowering time of soybean following the use of this fertilizer application method. Despite the lack of significant differences in the studied elements of yield structure, their values in many cases were comparable and even slightly higher; hence, a fertilizer that aligns with the assumptions of the circular economy is worth attention and further studies under field conditions. However, long-term studies are needed to test the cultivation of plants under field conditions and their reaction to struvite as well as the effect on the content of phosphatases, which stimulate the conversion of organic phosphorus compounds into inorganic phosphates, directly available to plants and soil organisms. [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]

• Pioneering application of Mn2+-based catalytic ozonation conditioning to in-situ sludge reduction. • Doubled the MLSS reduction rate in sludge and a 19% decrease in observed sludge yield. • Significant increase in peak dehydrogenase activity from 143.83 to 176.41 mg TF/g TSS·hr. • An 18% promotion in the maximum utilization of carbon sources by microorganisms. • Enhancement of sludge reduction and solubilization dominated by Defluviicoccus and Ferruginibacter. To improve the sludge conditioning efficiency without increasing the ozone dose, an in-situ sludge reduction process based on Mn2+-catalytic ozonation conditioning was proposed. Using ozone conditioning alone as a control, a lab-scale sequencing batch reactor coupled with ozonated sludge recycle was evaluated for its operating performance at an ozone dose of 75 mg O 3 /g VSS and 1.5 mmol/L Mn2+ addition. The results showed a 39.4% reduction in MLSS and an observed sludge yield of 0.236 kg MLSS/kg COD for the O 3 +Mn2+ group compared to the O 3 group (15.3% and 0.292 kg MLSS/kg COD), accompanied by better COD, NH 4 +-N, TN and TP removal, improved effluent SS and limited impact on excess sludge properties. Subsequently, activity tests, BIOLOG ECO microplates and 16S rRNA sequencing were applied to elucidate the changing mechanisms of Mn2+-catalytic ozonation related to microbial action: (1) Dehydrogenase activity reached a higher peak. (2) Microbial utilization of total carbon sources had an elevated effect, up to approximately 18%, and metabolic levels of six carbon sources were also increased, especially for sugars and amino acids most pronounced. (3) The abundance of Defluviicoccus under the phylum Proteobacteria was enhanced to 12.0% and dominated in the sludge, they had strong hydrolytic activity and metabolic capacity. Denitrifying bacteria of the genus Ferruginibacter also showed an abundance of 7.6%, they contributed to the solubilization and reduction of sludge biomass. These results could guide researchers to further reduce ozonation conditioning costs, improve sludge management and provide theoretical support. [Display omitted] [ABSTRACT FROM AUTHOR]

This research analyzes how enzymatic and microbiological soil properties relate to site index (SI) and forest maturity (stand age) in Pinus nigra (P. nigra) even-aged forests. The soil parameters selected for multivariate analysis were four enzymatic activities (β-glucosidase, urease, dehydrogenase, and alkaline phosphatase), two microbiological properties (microbial biomass C and basal respiration), and five physicochemical parameters (TOC, N, P, pH, and soil water content). We used LiDAR, the digital elevation model, and the terrain model to obtain a result for the dominant height in each plot. The soil parameters were analyzed in the function of five site index classes (8, 11, 14, 17, and 20) and six age classes (50, 70, 90, 110, 170, and 210 years). Our findings emphasize that the dehydrogenase enzyme exhibited variations in response to both the site index and stand age. The activity of dehydrogenase positively correlated with sites characterized by a higher nutrient demand, particularly on young and poor-quality sites (lower SI), indicating activation. Therefore, dehydrogenase could serve as an index to elucidate both site quality and stand development in P. nigra stands, making it a potential indicator of forest ecosystem development. [ABSTRACT FROM AUTHOR]

A field experiment was executed during the Rabi season at CSKHPKV, Palampur, to evaluate the effects of different weed control and nitrogen management practices on weed control, yield, nutrient content, dehydrogenase activity and the oil content of linseed. The experiment was set up in the RBD with 3 replicates consisting of fifteen treatment combinations comprising five weed controls (viz. isoproturon 1.25 kg/ha, clodinafop propargyl + metsulfuron methyl 60+4 g/ha, clodinafop propargyl + carfentrazone ethyl 60+10 g/ha, hand weeding twice and weedy check) and three nitrogen levels (i.e., FYM 5 t/ha, 75 and 100% RDN). The soil texture at the experimental site was silty clay loam, acidic and medium in available nitrogen, phosphorus and potassium. The results showed that the use of clodinafop propargyl + metsulfuron methyl 60+4 g/ha significantly decreased the count and dry matter content of the total weeds at the maximum count and dry matter stage. However, 1.25 kg/ha isoproturon was likewise effective at significantly reducing the total weed count and was the next best at reducing the dry matter content of the total weeds. The effective control of weeds by the application of isoproturon at 1.25 kg/ha (Post.) significantly increased plant growth without any toxicity, which contributed to increased nutrient uptake and increased seed, straw and oil yields in the linseed treatment. Among the nitrogen levels, a considerably lower count and dry matter content of the total weeds were recorded in the 100% RDN plots, followed by the 75% RDN treatment. The application of 100% RDN resulted in significantly greater NPK uptake than did the other treatments, which contributed to considerably greater seed, straw and oil yields. Thus, the application of isoproturon at 1.25 kg/ha (Post.) with 100% RDN was proven to be the most effective at realizing higher seed and oil yields with better weed control in linseed plants grown under utera conditions.

This study aims to compare the biodegradability efficiency of spent coolant waste by wild-type microalga versus mutagenised Scenedesmus vacuolatus. The biodegradation efficiency of both groups microalgae was evaluated using dehydrogenase activity (DHA) and total petroleum hydrocarbon (TPH) degradation using gas chromatography and mass spectrometry (GCMS). The DHA of both microalgae was conducted in relation to the triphenyl formazan production (TPF). The TPH of extracellular hydrocarbon degradation and intracellular hydrocarbons were analysed using GCMS. The data obtained from DHA and GCMS were analysed using analysis of variance at a 5% level of significance (0 < 0.05). The wild-type and mutagenised S. vacuolatus showed biodegradation of spent coolant waste after five weeks. The highest TPF produced by wild-type microalgae after five weeks was 1.139 mg/mL ± 0.009. The highest TPF produced by mutagenised S. vacuolatus after five weeks was 1.771 mg/mL ± 0.006 which was 1.55-fold higher than the TPF produced by the wild-type microalgae in the treatment weeks. The highest TPH degraded by wild-type after five weeks was 85.87% ± 0.20, while the highest TPH degradation of 100% was observed for the mutagenised S. vacuolatus after five weeks of spent coolant waste treatment. These results suggest that the mutagenised S. vacuolatus was better in utilising and degrading spent coolant waste and, therefore, can be used to mitigate spent oil pollution. [ABSTRACT FROM AUTHOR]

Soil quality assessment is important for arable land, particularly in the vicinity of urban areas. The research was carried out to determine the quality of soil that has been farmed for different land uses. Geo-referenced 200 surface soil samples were collected from agriculture, horticulture, flower and plantation land-uses, and were analyzed for soil texture and nutrients, of which pH, OC, N, P2O5, K2O, Mn, Cu, Ca, and dehydrogenase activity (DHA) were found statistically significant and were chosen for principal component analysis (PCA). Based on the level of significance from PCA only five variables (pH, K2O, Cu, Ca, and DHA) were retained for minimum data set and linear scoring functions were used to provide unit-less scores for the selected data sets, which were then integrated into a soil quality index (SQI). Plantation land use had the lowest (SQI) of 0.51, whereas agriculture land use had the highest SQI (0.55) and was comparable to flower and horticultural land uses (0.53). The SQI of agriculture land was found better than the plantation land use in nearly all of the quality indicators evaluated. As a result, implementing management measures that improve soil quality, such as OC, is critical for sustainable agricultural production. [ABSTRACT FROM AUTHOR]

The aim of the study was to assess the impact of plant extracts from hemp inflorescences (H10—10% and H20—20%), as well as a mixture of extracts from hemp inflorescences, sage, and tansy leaves (M10—10% and M20—20%) on phytotoxicity and selected physiological and biometric parameters of wheat seedlings, as well as the biological activity of soil in a growth chamber experiment. In all experimental combinations, a low phytotoxicity of the extracts was observed in the form of leaf tip yellowing, classified as first-degree damage or its complete absence. The plant extracts and their mixtures, except for the H20 extract, had an inhibitory effect on the development of fungal pathogens, especially Fusarium spp. The H20 extract increased the fresh and dry weight of root seedlings. The tested extracts also had a positive effect on the chlorophyll content in seedlings. The highest chlorophyll concentrations were recorded for the seedlings sprayed with the M20 extract mixture. The applied plant extracts influenced the activity of soil enzymes. The highest activity of catalase and dehydrogenases was observed after spraying seedlings with M20, while the lowest was recorded after applying H10. Of all the tested groups of soil environment compounds included in the Biolog EcoPlates test, carbohydrates and carboxylic acids were most actively utilized. Conversely, amines and amides constituted the group of compounds utilized the least frequently. The present study demonstrated the high effectiveness of plant extracts on wheat seedlings due to their biocidal action against phytopathogenic fungi and increased biological activity of the soil. This research serves as an initial phase of work, which will aim to verify the results obtained under field conditions, as well as assess the biological stability of the extracts.

The European Commission’s “Farm to Folk” (F2F) strategy recommends reducing fertilizers by at least 20% by 2030. In this aspect, the main goal of our study was to verify whether a 20 and even 40% reduction in nitrogen (N) fertilization rate would be sufficient to maintain soil fertility (expressed as dehydrogenase activity—DHA, humic acid substances—HA substances, E4/E6 ratio), and yields of wheat and rapeseed cultivated in strip-till technology. Two fields (10 ha each) were established for wheat and rapeseed cultivation, and soils (0–20 cm) were sampled before sowing and after harvesting. It was found that a 20% fertilization reduction does not adversely affect the biological activity expressed by DHA. Nevertheless, the reduction in nitrogen (N) fertilizer rates led to a slight decrease in the E4/E6 ratio, which could serve as a potential indicator of fertilization reduction. DHA, E4/E6 ratio and content of HA substances were also dependent on the crop. Following harvesting, both rapeseed and wheat exhibited a positive correlation between the E4/E6 ratio and the degree of fertilization rate (FR), as well as yield.

AbstractThere is currently a great deal of information available about the toxic effects of oxyfluorfen on soil biochemical activity and microbial biodiversity. However, there is no information about how this herbicide affects plant growth promoting bacteria (PGPB) or their properties, such as biofilm formation, nitrogen fixation, siderophore and auxin production, and phosphate solubilisation. As such in this study an agricultural soil was polluted with the oxyfluorfen herbicide every 30 days at a dose of 4 L ha−1 for a total period of 90 days. During this experimental period, the dehydrogenase activity was determined, a count and isolation of cultivable bacteria was performed, and the PGPB and their properties were characterized. The results indicated that oxyfluorfen inhibits the dehydrogenase activity, with this inhibition increasing with herbicide concentration in the soil (69.9% compared to non-polluted soil). It also causes changes in the population diversity of cultivable bacteria in soils. Regard to the evolution of isolated PGPB, it was found that oxyfluorfen induces the growth of nitrogen-fixing, biofilm-forming, and siderophore-producing bacteria, while negatively affecting the growth of auxin-producing and phosphate-solubilising bacteria. These results suggest that oxyfluorfen modulates the properties of PGPB in a concentration-dependent manner.

Soil microbial activity (SMA) is vital concerning carbon cycling, and its functioning is recognized as the primary factor in modifying soil carbon storage potential. The composition of the microbial community (MC) is significant in sustaining environmental services because the structure and activity of MC also influence nutrient turnover, distribution, and the breakdown rate of soil organic matter. SMA is an essential predictor of soil quality alterations, and microbiome responsiveness is imperative in addressing the escalating sustainability concerns in the Himalayan ecosystem. This study was conducted to evaluate the response of soil microbial and enzyme activities to land conversions in the Northwestern Himalayas (NWH), India. Soil samples were collected from five land use systems (LUSs), including forest, pasture, apple, saffron, and paddy-oilseed, up to a depth of 90 cm. The results revealed a significant difference (p < 0.05) in terms of dehydrogenase (9.97-11.83 TPF µg g-1 day-1), acid phosphatase (22.40-48.43 µg P-NP g-1 h-1), alkaline phosphatase (43.50-61.35 µg P-NP g-1 h-1), arylsulphatase (36.33-48.12 µg P-NP g-1 h-1), fluorescein diacetate hydrolase (12.18-21.59 µg g-1 h-1), bacterial count (67.67-123.33 CFU × 106 g-1), fungal count (19.33-67.00 CFU × 105 g-1), and actinomycetes count (12.00-42.33 CFU × 104 g-1), with the highest and lowest levels in forest soils and paddy-oilseed soils, respectively. Soil enzyme activities and microbial counts followed a pattern: forest > pasture > apple > saffron > paddy-oilseed at all three depths. Paddy-oilseed soils exhibited up to 35% lower enzyme activities than forest soils, implying that land conversion facilitates the depletion of microbiome diversity from surface soils. Additionally, reductions of 49.80% and 62.91% were observed in enzyme activity and microbial counts, respectively, with soil depth (from 0-30 to 60-90 cm). Moreover, the relationship analysis (principal component analysis and correlation) revealed a high and significant (p = 0.05) association between soil microbial and enzyme activities and physicochemical attributes. These results suggest that land conversions need to be restricted to prevent microbiome depletion, reduce the deterioration of natural resources, and ensure the sustainability of soil health. [ABSTRACT FROM AUTHOR]

Restoration and optimisation of soil processes is an important task of modern agriculture and one of the reserves for increasing agricultural production. Under the current conditions, this becomes possible with the integrated introduction of ecologised fertiliser systems. The purpose of the study is to investigate the regularities of the development of biological features of grey forest soil, the interdependencies between them, and the productivity of winter wheat in ecologised fertiliser systems. The following methods were used in the study: field, laboratory and analytical, biochemical, mathematical and statistical. Patterns of changes in situ of cellulolytic, proteolytic, and actual dehydrogenase activities of the soil, the carbon content of labile humus, and the number and weight of winter wheat grains per unit area were similar to each other. There was a decrease in cellulolytic activity, the smallest increase in the remaining biological characteristics of the soil under the use of pea straw, compared to the control. The greatest cellulolytic or proteolytic activity occurred in pea straw + N30P45K45 + biostimulator + humus fertiliser or pea straw + N30P45K45 + biostimulator + microbiological fertiliser, respectively, dehydrogenase – in 2, and the content of labile humus – in the first of these 2 variants. The availability of carbon and nitrogen allowed explaining the identified patterns in a relevant way. The positive Pearson correlation coefficients between plant productivity and soil biological activity, labile humus content, and enzymatic activity, and the insignificant partial correlation coefficients between these variables are partly conditioned by multicollinearity and multivariate interdependencies. In the future, the research would provide a deeper understanding of the patterns of development of biological properties of the soil under ecological fertiliser systems. This would help to improve the elements of greening to adjust the ratio of potential and actual fertility to the optimal level. Scientific results can become a basic basis for the development of effective soil-protecting organic and mineral fertiliser systems for economic and industrial structures of various levels of intensity and financial viability

Windthrows in the forestry fund, which have become more frequent due to the increase in extreme weather events, have had, and continue to have, mostly negative economic and ecological effects, making them a pressing issue in forestry research. The main objectives of this study are to evaluate the effects of windthrows on some microbiological properties of forest soils and to monitor the evolution of the degraded tree regeneration, four years after the event, for three tree species: Norway spruce (Picea abies L.), sessile oak (Quercus petraea), and European beech (Fagus sylvatica L.). The experimental plot used is arranged in dispersed blocks and subdivided plots, with three repetitions, and is bifactorial, with factor A representing the tree species and factor B the windthrows. There are two possibilities: affected by windthrows (AW) and unaffected by windthrows (WW). For each tree species, dehydrogenase activity (DA) and the number of fungi (NF) in the organic horizon at the soil surface were studied. Correlations were highlighted between the differences in AW and WW of Current Dehydrogenase Activity (CDA), Potential Dehydrogenase Activity (PDA), and NF with the number of naturally regenerated seedlings (NRS) and the type of soil. Stimulating NRS in AW forests and increasing the volume of terrestrial organic carbon (TOC) biomass is directly dependent on soil fertility, primarily determined by Soil Organic Carbon (SOC), which accumulates in the soil as a result of organic matter, deposited on the surface. Sustainable forest management of AW plots should stimulate the accumulation of SOC, including the partial or total preservation of dead trees, provided that the attack of specific diseases and pests is avoided. [ABSTRACT FROM AUTHOR]

With a shortage of sulfur in the soil and an increasing world population and, thus, food consumption volume, the demand for this important nutrient is likely to increase, both globally and regionally. The purpose of this model incubation study was to evaluate the effect of fertilizer granule applications containing elemental sulfur, halloysite and phosphate rock on the content of the bioavailable form of sulfur and phosphorus, as well as dehydrogenase activity and pH value of two soils differing in granulometric composition and chemical parameters. In addition to the standard procedure of analysis of variance, the authors propose various methods of advanced statistical analysis: regression modeling, including simple regression and multiple regression, or multivariate methods of grouping objects and traits resulting in the creation of heatmaps. With respect to the control, the application of fertilizer granules generally had no significant effect on the content of available phosphorus and the activity of dehydrogenase, and had little effect on the degree of acidity of the soils tested. There was a greater effect of introducing fertilizer granules on the content of sulfate sulfur in heavy soil than in medium soil. Using advanced statistical techniques revealed relationships between the studied soil parameters and changes in their values as affected by the experimental factors. [ABSTRACT FROM AUTHOR]

In order to protect and remediate soils, organic farming methods have grown in popularity. The aim of the study was to evaluate the effect of rhizobacteria (Bacillus subtilis, Bacillus amyloliquefaciens, Pseudomonas fluorescens) and catch crops (undersown red clover alone, undersown Italian ryegrass alone and a mixture of clover and ryegrass) on the microbiological activity of the soil under organic spring barley. In 2019–2021, a field experiment was carried out on an organic farm, randomly in eight variants, each in three repetitions. The following parameters were analyzed: enzymatic activity of dehydrogenases (DHA), acid phosphatase (PAC) and catalase (CAT), soil fertility index (BIF), and a number of selected physiological groups of microorganisms (molds, bacteria, and actinomycetes). Compared to the control variant (without catch crops and bacteria), the values of DHA, CAT, and BIF increased significantly in the variant in which rhizobacteria and catch crops were used simultaneously. The highest BIF, of 32, was obtained in 2019, after the application of red clover catch crop + Italian ryegrass + rhizobacteria. PAC activity dropped significantly after the application of the bacterial consortium alone and was lower than the control by an average of 30%. [ABSTRACT FROM AUTHOR]

Soil microbial activity (SMA) is vital concerning carbon cycling, and its functioning is recognized as the primary factor in modifying soil carbon storage potential. The composition of the microbial community (MC) is significant in sustaining environmental services because the structure and activity of MC also influence nutrient turnover, distribution, and the breakdown rate of soil organic matter. SMA is an essential predictor of soil quality alterations, and microbiome responsiveness is imperative in addressing the escalating sustainability concerns in the Himalayan ecosystem. This study was conducted to evaluate the response of soil microbial and enzyme activities to land conversions in the Northwestern Himalayas (NWH), India. Soil samples were collected from five land use systems (LUSs), including forest, pasture, apple, saffron, and paddy-oilseed, up to a depth of 90 cm. The results revealed a significant difference (p < 0.05) in terms of dehydrogenase (9.97–11.83 TPF µg g−1 day−1), acid phosphatase (22.40–48.43 µg P-NP g−1 h−1), alkaline phosphatase (43.50–61.35 µg P-NP g−1 h−1), arylsulphatase (36.33–48.12 µg P-NP g−1 h−1), fluorescein diacetate hydrolase (12.18–21.59 µg g−1 h−1), bacterial count (67.67–123.33 CFU × 106 g−1), fungal count (19.33–67.00 CFU × 105 g−1), and actinomycetes count (12.00–42.33 CFU × 104 g−1), with the highest and lowest levels in forest soils and paddy-oilseed soils, respectively. Soil enzyme activities and microbial counts followed a pattern: forest > pasture > apple > saffron > paddy-oilseed at all three depths. Paddy-oilseed soils exhibited up to 35% lower enzyme activities than forest soils, implying that land conversion facilitates the depletion of microbiome diversity from surface soils. Additionally, reductions of 49.80% and 62.91% were observed in enzyme activity and microbial counts, respectively, with soil depth (from 0–30 to 60–90 cm). Moreover, the relationship analysis (principal component analysis and correlation) revealed a high and significant (p = 0.05) association between soil microbial and enzyme activities and physicochemical attributes. These results suggest that land conversions need to be restricted to prevent microbiome depletion, reduce the deterioration of natural resources, and ensure the sustainability of soil health.

This study aimed to investigate the effects of different voltage and aeration conditions on catering wastewater treatment and membrane fouling in a novel annular electric field membrane bioreactor (AEMBR). The results indicated that the synergistic effect of annular electric field and aeration promoted the degradation of wastewater and the alleviation of membrane fouling. The treatment effect was optimal under a micro electric field of 0.5 V, with removal rates for COD, NH 4 +-N, TP, and oil ranging from 96.85% to 99.36%, 80.43%–83.01%, 95.46%–97.79%, and 98.83%–99.15%, respectively. Additionally, the fluorescence intensity of macromolecular proteins and small molecular acids decreased. Simultaneously, the average growth rate of transmembrane pressure (TMP) reduced by approximately 0.4 kPa/d. The species abundance and diversity of activated sludge increased, promoting the growth of dominant bacteria, all while maintaining low energy consumption. The aeration intensity had relatively little impact on system operation, and the force of the annular electric field was greater than the force of aeration. This study verified the optimal benefits under micro electric field conditions and provided a basis for the optimization of future process design to achieve a more efficient and economical wastewater treatment system. [Display omitted] • Micro electric fields are more conducive to AEMBR operation. • Too high voltage will destroy sludge properties and microbial activity. • Medium aeration is more conducive to alleviating membrane fouling. • The removal effect of pollutants is better under high aeration. • The electric field force is greater than the aeration force. [ABSTRACT FROM AUTHOR]

Nowadays, antibiotic-polluted soils have raised concerns regarding the health of soil ecosystems. It has been suggested that biochar can be used as an amendment to improve soil health conditions in polluted sites. The present research aimed to investigate the influence of walnut shell biochar and methanol-activated walnut shell biochar on tetracycline concentration in the presence of copper and the assessment of soil biological parameters (microbial biomass, urease and dehydrogenase enzymes). Therefore, a factorial experiment was conducted as a completely randomized design. The factors included two biochar levels without or with copper (0% biochar (control soil), soil amended with 5% walnut shell biochar and soil amended with 5% methanol-activated walnut shell biochar) and two tetracycline levels (0 and 400 mg/kg soil), which were measured at 10-, 30- and 50-day intervals. The results revealed that biochar and methanol-activated biochar efficiently decreased tetracycline concentration up to 46.5% and 80.4%, respectively. The application of biochar decreased tetracycline concentration through the formation of a stable complex with tetracycline and the reduction of its extractability as well as biodegradation. The decrease in tetracycline extractability was also facilitated by the presence of copper. Neither biochar had significant effects (P > 0.05) on microbial biomass. They also reduced enzymatic activities, probably due to a high application rate. However, they weakened the negative effects of tetracycline on microbial activities. It was concluded that the application of biochar in tetracycline-polluted soils could help expedite the decrease of residual tetracycline concentration, which, in turn, could improve soil biological parameters and soil health. [ABSTRACT FROM AUTHOR]

In this study, we investigated the sorption–desorption behavior of imazamox (IMZ) and 2,4-DB (DB) in two typical acidic Mediterranean agricultural soils and the impact of these herbicides on culturable soil bacterial populations, enzyme activities and functional diversity when applied at concentrations higher than recommended doses (10×, 50×, 500×). Herbicide sorption was similar in both soils and IMZ was less retained compared to DB (~0.5 vs. 40 µg g−1 soil, respectively). IMZ desorption was remarkable (70–100%) while that of DB was more limited, i.e., ~40%. Three days after spiking (DAS), IMZ and DB significantly increased the number of soil-culturable heterotrophic bacteria, actinomycetes and Pseudomonas spp., soil respiration and the potential catabolic capacity of soil microbial communities. Soil dehydrogenase activity increased by ~56–70% in IMZ-treated soils while being reduced by ~33–41% in DB-treated ones. β-glucosidase activity showed a soil-dependent behavior, while the pattern of C source utilization suggested a change of soil microbial community structure after herbicide (especially DB) spiking. At 30 DAS, the herbicides' impact on soil microorganisms, enzyme activity and functional diversity was still visible. Moreover, a toxic effect of DB (at 50× and 500×), but not IMZ, was recorded vs. Rhizobium sullae, the bacterial symbiont of Hedysarum coronarium. The obtained results indicated that IMZ and DB are poorly sorbed and highly desorbed by both soils. Moreover, at the tested concentrations, IMZ and DB can have short- and medium-term impacts on the microbial component and the related activity of the investigated soils, likely affecting a range of ecosystem services provided by soil microorganisms. [ABSTRACT FROM AUTHOR]

The size of the microbial biomass and the activity of soil enzymes are among the most sensitive indicators of agricultural land quality. The aim of this study was to determine the spatial and temporal variability of microbial biomass, the activity of dehydrogenase (DHA) enzyme and the concentration of micro- (Na, Mg and Ca) and macroelements (Cu, Zn, Mn and Fe) in the soil, collected from 37 measurement sites (depth 0–30 cm) in a 40-hectare field during two growing seasons (wheat and oilseed rape). The percentage of nitrogen (%N) in the wheat grain and rapeseeds was also determined. Mapping the spatial distribution of the microbial biomass, the level of DHA activity and the concentration of the selected elements was used to assess the soil productivity. All tested soil parameters exhibited temporal and spatial variability. The creation of raster maps showing the distribution of the tested parameters allowed the observation of a higher nitrogen content in wheat grains in the south-western part of the field, with high values of DHA activity, bacterial biomass and soil pH. In the case of oilseed rape, plants grown in the northern part of the field were characterized by a higher nitrogen content in the grain, where the soil was characterized by a higher content of fungal biomass. On the basis of the obtained research results, a positive, statistically significant correlation was also shown between the biomass of bacteria and the level of DHA in the soil under the cultivation of both wheat and rape. The cultivation of both crops had a significant impact on the size of the microbial biomass pool and on the DHA activity level but did not affect the concentration of the nutrients in the soil. High concentrations of the analyzed elements at the measuring points correlated with a greater %N content in the grain/seeds of the crops harvested at those locations in the field. The results conclude that the mapping of the physicochemical parameters, microbial biomass and activity on the field permits the development of an effective strategy for maintaining sustainable soil productivity through the appropriate management of agricultural practices and the better approximation of mineral fertilization. [ABSTRACT FROM AUTHOR]

Abstract Background Antibiotic resistance has contributed to the burden of infectious diseases both in the hospital and community setting, and represents a great threat to public health. Previous studies have revealed the role of reactive oxygen species as intermediate mediators of tissue damage, following antibiotherapies, indicating the need of associating antioxidants to these treatments. Therefore, the present work was designed to study the antibacterial, antifungal and antioxidant activities of extracts and compounds from Rumex abyssinicus Jacq. (Polygonaceae), as well as to investigate the antibacterial mechanisms of action of the most effective agents. Methods The plant extracts were prepared by maceration in organic solvents followed by column chromatography of the EtOAc fraction and purification of different fractions which led to the isolation and characterization of pure compounds. The antimicrobial activities of the extracts/compounds and their combinations with ciprofloxacin and fluconazole were evaluated using the broth microdilution method by determining the minimum inhibitory concentration (MIC) and minimum microbicidal concentration (MMC). The effects of the extracts on the bacterial cell membrane and microbial respiratory chain dehydrogenase enzyme activity were determined by spectrophotometric methods. Antioxidant activity was evaluated using 1,1-diphenyl-2-picrylhydrazyl (DPPH) and gallic acid equivalent antioxidant capacity (GAEAC) assays. Results Chrysophanol (1), physcion (2), Ergosta-6,22-diene-3,5,8-triol (3), emodin (4), 6-hydroxyemodin (citreorosein) (5), chrysophanein (6) and physcionin (7) were isolated from EtOAc fraction of R. abyssinicus and displayed different degrees of antimicrobial activities (MIC = 8–256 μg/mL). The MeOH extract and compounds 2 and 4 exhibited synergistic effects with ciprofloxacin and fluconazole. Compounds 1, 2 and the combined mixture of 6 + 7 displayed the highest antioxidant activity (GAEAC = 83.38–106.03 μg/mL). Conclusion R. abyssinicus is a potential source of antibacterial, antifungal and antioxidant agents. The antibacterial mechanisms of action of the MeOH extract and compound 2 are due to disruption of the cytoplasmic membrane and inhibition of the microbial respiratory chain dehydrogenase enzyme activity. To the best of our knowledge, this is the first report of test samples and ciprofloxacin / fluconazole association against MDR strains. The observed activity of the isolated compounds against bacteria and fungi including MDR strains deserves further exploration.

With a shortage of sulfur in the soil and an increasing world population and, thus, food consumption volume, the demand for this important nutrient is likely to increase, both globally and regionally. The purpose of this model incubation study was to evaluate the effect of fertilizer granule applications containing elemental sulfur, halloysite and phosphate rock on the content of the bioavailable form of sulfur and phosphorus, as well as dehydrogenase activity and pH value of two soils differing in granulometric composition and chemical parameters. In addition to the standard procedure of analysis of variance, the authors propose various methods of advanced statistical analysis: regression modeling, including simple regression and multiple regression, or multivariate methods of grouping objects and traits resulting in the creation of heatmaps. With respect to the control, the application of fertilizer granules generally had no significant effect on the content of available phosphorus and the activity of dehydrogenase, and had little effect on the degree of acidity of the soils tested. There was a greater effect of introducing fertilizer granules on the content of sulfate sulfur in heavy soil than in medium soil. Using advanced statistical techniques revealed relationships between the studied soil parameters and changes in their values as affected by the experimental factors.

In order to protect and remediate soils, organic farming methods have grown in popularity. The aim of the study was to evaluate the effect of rhizobacteria (Bacillus subtilis, Bacillus amyloliquefaciens, Pseudomonas fluorescens) and catch crops (undersown red clover alone, undersown Italian ryegrass alone and a mixture of clover and ryegrass) on the microbiological activity of the soil under organic spring barley. In 2019–2021, a field experiment was carried out on an organic farm, randomly in eight variants, each in three repetitions. The following parameters were analyzed: enzymatic activity of dehydrogenases (DHA), acid phosphatase (PAC) and catalase (CAT), soil fertility index (BIF), and a number of selected physiological groups of microorganisms (molds, bacteria, and actinomycetes). Compared to the control variant (without catch crops and bacteria), the values of DHA, CAT, and BIF increased significantly in the variant in which rhizobacteria and catch crops were used simultaneously. The highest BIF, of 32, was obtained in 2019, after the application of red clover catch crop + Italian ryegrass + rhizobacteria. PAC activity dropped significantly after the application of the bacterial consortium alone and was lower than the control by an average of 30%.

Heterocyclic nitrogen compounds containing two adjacent nitrogen atoms generally have a significant effect on soil nitrification inhibition, and 3,5-dimethylpyrazole (DMP) is a typical representative of this structure. However, the inhibitory effect and the regulatory mechanism of DMP on soil N transformation are unclear. In this study, a microcosm with different concentrations of DMP was carried out in brown soil to detect the dynamic changes of soil NH4+–N, NO3–N and related soil enzyme activities. Results showed that DMP inhibited soil nitrification effectively and decreased soil nitrate reductase activity, while increasing nitrite reductase and dehydrogenase activities. The inhibition effects were dose dependent, and DMP at the rate of 0.025 g kg−1 dry soil showed the strongest inhibitory effect on N transformation in brown soil. The soil dehydrogenase activity was increased with an increasing DMP application rate. The changes in the soil's chemical and biological properties caused by DMP application provided a new idea for systematically explaining how DMP participated in the soil N transformation process. This study further implied that DMP would play positive roles in alleviating environmental pressure by delaying nitrate-N formation and decreasing the activity of nitrate reductase. [ABSTRACT FROM AUTHOR]

Clopyralid and imazamox are successfully used for weed control during the first years of regeneration of pedunculate oak forests. Hence, the question that arises is how these herbicides affect microorganisms, especially the activity of dehydrogenase enzyme, when they reach the soil. Two study sites were selected in regenerated pedunculate oak forests, and the two herbicides were applied in two doses that are used for weed control (clopyralid, 100 g a.i. ha−1 and 120 g a.i. ha−1; imazamox, 40 g a.i. ha−1 and 48 g a.i. ha−1). The effect of the herbicides was evaluated 7, 14, 21, 30, and 60 days after application. A significant reduction in dehydrogenase activity was found on days 7 and 14 at both sites. However, after 14 days there was a recovery of dehydrogenase activity for all treatments such that the values obtained on day 21 did not differ from the control values. The effect of clopyralid and imazamox on dehydrogenase activity was not dose-dependent. Dehydrogenase activity also depended on soil properties, soil sampling time and climatic conditions during the investigation years. The results show that clopyralid and imazamox can reduce soil dehydrogenase activity, but this effect is transient. This can be attributed to the ability of microorganisms to overcome the stress caused by the herbicide by developing the capability to utilize herbicides as a nutrient source and proliferating in such an environment. [ABSTRACT FROM AUTHOR]

The use of biochar in soil remediation is a promising method to deal with metal contamination. In the present study, the influence of biochar amendment on the toxicity of silver (as AgNO3) to terrestrial organisms was assessed. For this, toxicity tests were conducted with terrestrial plant barley (Hordeum vulgare) and invertebrate springtails (Folsomia candida) in the standard natural Lufa soil amended or not with a wood-derived biochar at 5% (w/w). Biochar addition increased root length and mass in barley, compared to unamended soil. However, the effects of Ag on barley growth were masked by a great variation among replicates in biochar-amended soil. Photosynthetic pigment contents (total chlorophyll and carotenoids) were lower in plants exposed to Ag in Lufa soil, but not in biochar-amended soil. Moreover, Ag drastically decreased dehydrogenase activity in Lufa soil. For springtails, the addition of biochar clearly decreased the toxicity of Ag. The LC50 was 320 mg Ag/kg in Lufa soil, while no mortality was observed up to 500 mg Ag/kg in biochar-amended soil. The EC50 for effects on reproduction was significantly higher in biochar-amended soil compared to unamended Lufa soil (315 and 215 mg Ag/kg, respectively). The wood-derived biochar used in this study has shown a potential for remediation of contaminated soils, as a decrease in Ag toxicity was observed in most endpoints analysed in barley and springtails. [ABSTRACT FROM AUTHOR]

The soil–plant interaction may help in maximizing crop productivity with simultaneous improvement in the soil quality. Field experiments were conducted during 2014 to 2016 to evaluate the planting systems with polythene mulching on soil hydrothermal conditions, nutrient availability, and crop productivity under cauliflower–eggplant cropping systems involving six treatments such as T1: flat-bed without polythene mulch; T2: flat-bed with polythene mulch; T3: broad-bed without polythene mulch; T4: broad-bed with polythene mulch; T5: ridge-furrow without polythene mulch; T6: ridge-furrow with polythene mulch. The daily mean surface soil temperature in mulched plots was 1.3°C higher than unmulched during the early growing season. The microbial biomass carbon (SMBC), soil organic carbon (SOC), dehydrogenase activity (DHA), and acid phosphatase activity of soil were higher in the mulched treatments. The mulched ridge-furrow treatment (T6) recorded the highest available N, P, and K content of 286.4, 37.2, and 315.2 kg ha−1 in eggplant, accounting for 38.2, 52.4, and 26.0% increase over the initial status, while in cauliflower, it was 275.1, 36.4, and 300.4 kg ha−1, accounting for 32.7, 49.2, and 20% increase, respectively. The highest N, P, and K uptake by cauliflower was 172.4, 17.1, and 117.7 kg ha−1, while in eggplant, it was 88.3, 22.4, and 91.4 kg ha−1, respectively, in T6 treatment. The curd yield of cauliflower and fruit yield of eggplant was significantly highest of 40.4 and 29.8 t ha−1, respectively, in T6 treatment. [ABSTRACT FROM AUTHOR]

Vermicompost has been promoted as a viable substrate component owing to its physicochemical properties, nutrient richness, and status as an excellent soil improver. It is considered the best organic fertilizer and is more eco-friendly than chemical fertilizers. Plant-growth-promoting microorganisms (PGPMs) are defined as plant biofertilizers that improve nutritional efficiency—that is, they transform nutrients within substrates from organic to inorganic forms, making them available for plants. The main objective of this research study is to evaluate the effects of the application of three PGPM microbial consortia on different mixtures of organic substrates based on vermicompost (V) and coconut fiber (CF) on two different horticultural crops. We performed a yield analysis and drainage nutrient tests and determined the plant nutritional status and enzymatic activity in organic substrates based on the two crops, Cucumis melo L. and Solanum lycopersicum L. A multivariate analysis of variance and principal component analysis was conducted using substrate types and PGPMs as factors. Differences (p < 0.05) in yield, dehydrogenase activity, the nutrient concentrations in a petiole sap, and drainage were observed at 30, 60, 75, and 90 days after transplant. PGPMs such as Trichoderma sp. and plant-growth-promoting rhizobacteria (PGPR) in organic substrates (40V + 60CF) can significantly improve the nutritional status of plants for use in organic soilless container agriculture. Biofertilization with PGPMs and suitable mixtures of organic substrates together with aqueous extracts (tea) of vermicompost, as nutrient solutions applied by fertigation, has allowed us to achieve an adequate level of production through environmentally friendly techniques. The results obtained allowed us to affirm that it was possible to replace conventional fertilization using no chemical products and ensure adequate crop nutrition by supplying main macronutrients with organic sources and biofertilizers. [ABSTRACT FROM AUTHOR]

Pyroligneous acid (PA) is often used in agriculture as a plant growth and yield enhancer. However, the influence of PA application on soil microorganisms is not often studied. Therefore, in this study, we investigated the effect of PA (0.01–5% w/w in soil) on the microbial diversity in two different soils. At the end of eight weeks of incubation, soil microbial community dynamics were determined by Illumina-MiSeq sequencing of 16S rRNA gene amplicons. The microbial composition differed between the lower (0.01% and 0.1%) and the higher (1% and 5%) concentration in both PA spiked soils. The lower concentration of PA resulted in higher microbial diversity and dehydrogenase activity (DHA) compared to the un-spiked control and the soil spiked with high PA concentrations. Interestingly, PA-induced plant growth-promoting bacterial (PGPB) genera include Bradyrhizobium, Azospirillum, Pseudomonas, Mesorhizobium, Rhizobium, Herbaspiriluum, Acetobacter, Beijerinckia, and Nitrosomonas at lower concentrations. Additionally, the PICRUSt functional analysis revealed the predominance of metabolism as the functional module's primary component in both soils spiked with 0.01% and 0.1% PA. Overall, the results elucidated that PA application in soil at lower concentrations promoted soil DHA and microbial enrichment, particularly the PGPB genera, and thus have great implications for improving soil health. [ABSTRACT FROM AUTHOR]

One of the most important food sources for humans is the soybean crop because it is an important source of protein and oil, which makes it important to improve its productivity under stress conditions, especially in sandy lands. Therefore, the study aimed to improve soybean productivity by using biological fertilizers in the presence of organic fertilizer and low concentration of mineral fertilizer under new sandy soil conditions. The experiment was carried out in two summer seasons of 2020 and 2021 at the Ismailia Research Station, Ismailia Governorate. The used inoculates in the experiment were, an identified Streptomyces strain, Bacillus megatherium, (SEWRI) and Bradyrhizobiumjaponicum (Okaden) as, biofertilizer agents. Activated dose of N-fertilizer was used in seven different treatments. Results showed that Bradyrhizobia+Bacillus+actinomycetes+20 kg nitrogen fertilizer/fed was effective in the presence of organic fertilizer compared to organic fertilizer-free soil or un-inoculated+70 kg N/fed. Bradyrhizobia+ Bacillus+Actino+20 kg N/fed (T14) was the most effective treatment in the presence of organic fertilizer compared to organic fertilizer-free soil or uninoc.+70 kg N/fed. Promising expected yields of each of seeds and straw (Ton/fed) of soybean plants cultivated under different fertilizers and biofertilizers conditions expected was clear from increasing the yield seed up to 1.8400Ton/fed in the presence of organic fertilizer (T14) compared to 1.4565 when soybean was cultivated in the absence of organic fertilizer (T01). This could be supported by the amounts of NPK, N-percentage, and protein content, numbers of branches and pods and dehydrogenase activity in soil. Significant differences between the straw yield in the presence and absences of organic fertilizer as well as biofertilizers were recorded. Organic fertilizer application recorded the highest significant increases in nodulation status, growth and straw nitrogen content as well as harvest parameter of soybean compared with those un-received organic fertilizer. [ABSTRACT FROM AUTHOR]

We explored the effects of two modified carriers on the performance of anaerobic ammonia oxidation (anammox) reactor, taking the up-flow anaerobic sludge bed(UASB) as the research object, and analyzed the reasons for the differences of the reactor performance were analyzed from the microscopic aspects by some molecular biological techniques such as scanning electron microscope (SEM), dehydrogenase activity and high-throughput sequencing. Results show that not only activated carbon polyurethane but also modified polyethylene plastic improved the performance of anaerobic ammonia oxidation reactor. When the nitrogen loading rate reached 1. 37 kg/(m³ • d), the total nitrogen removal rate of those two reactors still had 76.41% and 82.89% respectively, but the control reactor only has 70. 26%. Moreover, as shown by combining with the results of SEM and high-throughput sequencing, the reactor with two modified carriers had a good enrichment effect on the anaerobic ammoxidation bacteria, and the enrichment efficiency of the modified polyethylene plastic was better. The dehydrogenase activity of the sludge of the two UASB reactors with modified carriers was higher than that of the control group. Meanwhile the dehydrogenase activity of the surface biofilm of the modified polyethylene plastic was higher than that of activated carbon polyurethane, resulting in different performance of three anammox reactors. In general, the modified polyethylene plastic filler has a better effect on improving the performance of the reactor but also enriching in anammox bacteria. [ABSTRACT FROM AUTHOR]

Currently there is a growing interest both in obtaining large agricultural yields in order to provide food for a growing population as well as in increasing the sustainability of production systems by improving the health of the soil. The overall objective of this study was to evaluate the effect of organic versus chemical fertilization versus irrigation on runner bean crop and soil health. A bi-factorial field experiment was organized in a split plot design with three replicates during two years (2019 and 2020). The first factor, irrigation, had two graduations: irrigated with 3000 m³·ha-1 (Ir) and non-irrigated (Non-Ir). The second factor, fertilization, had four graduations: biosolids (1200 kg·ha-1) (B), chemical (360 kg·ha-1) (Ch), microorganism (80 kg·ha-1) (M) and unfertilized (Unfert). The results showed that, regarding the physiological state of the plants, both the photosynthesis and the chlorophyll content were higher at Ir x M (5.31 µmol CO2 m-2 s-2 and 45.23 SPAD units, respectively). The yield of dried beans ranged between 1476-4811 kg·ha-1 in 2019 and 1498-4727 kg·ha-1 in 2020 and was highest for Ir x Ch. Soil health status estimated by determining the dehydrogenase activity in the soil, has been improved for irrigated (Ir) and fertilized (B, M, Ch) variants. [ABSTRACT FROM AUTHOR]

Within a 30-day incubation laboratory study, the polycyclic aromatic hydrocarbon (PAH) degradation profile of two bacteria, Planomicrobium sp. RNP01 and Rhodococcus sp. RNP05 were studied by three microtiter plate assays to reveal the combination of certain biological and biochemical characteristics which are reliable indicators in evaluation of bacterial biodegradation abilities. The three assays, which are hydrocarbon growth assay, 2,6-DCPIP assay and dehydrogenase activity assay revealed that Rhodococcus sp. RNP05 exhibited better potential for PAH degradation than Planomicrobium sp. RNP01. Differences between initial and final optical density and specific growth rate constants were significantly higher (r = 0.995, P < 0.05) in case of Rhodococcus sp. RNP05 on all tested substrates, as compared to Planomicrobium sp. RNP01. This was confirmed by GC-FID analyses. Dehydrogenase activity of Rhodococcus sp. RNP05 was higher (r = 0.9995, P < 0.05) than Planomicrobium sp. RNP01 and correlated positively with the hydrocarbon growth assay (r = 0.999, P < 0.05, for Rhodococcus sp. RNP05, r = 0.986, P < 0.05 for Planomicrobium sp. RNP01). This study has shown that the combination of these assays could be used for determining the bioremediation potential of PAHs in petroleum contaminated soil with the ability of screening a large number of bacterial strains. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. III43004]

In this work, chitosan/caffeic acid mixtures in the weight ratios of 80/20 and 50/50 were used to obtain thin films enriched with poly(ethylene glycol). It was hypothesized that the presence of caffeic acid indicates the antibacterial properties of the materials (i) and that poly(ethylene glycol) acts as a films modifier (ii). The results showed that by poly(ethylene glycol) addition, the surface free energy as well as mechanical and thermal properties were improved. Moreover, water vapor permeability was observed. All the tested materials showed antioxidant properties in the range of approximately 90%. They also showed antibacterial effectiveness against both Gram-positive and Gram-negative bacteria. The most appropriate material for the application as packaging was composed of chitosan and caffeic acid mixed in a 50/50 weight ratio with 20% PEG addition. [ABSTRACT FROM AUTHOR]

Cotton is a crop that has a high demand for nutrients. To obtain higher yields nutrients must be supplied as per the crop demand and must be available to the crop. Therefore, a field experiment was conducted at the Main Agricultural Research Station, Dharwad during kharif 2019 and 2020 to assess the soil enzyme activity as influenced by Bt cotton genotypes and optical sensor-based nitrogen management practices. Pooled data revealed that genotypes did not show any significant difference for soil dehydrogenase (P = .2899), phosphatase (P = .0165) and urease (P = .1481) enzyme activity at mid flowering stage. Different optical sensor-based nitrogen management practices significantly (P<.0001) influenced soil dehydrogenase, phosphatase and urease enzyme activity at the mid flowering stage. Nitrogen (N) supplementation at 81-90 % sufficiency index (SI) (43.69 μg TPF g-1 Soil day-1) recorded significantly higher dehydrogenase enzyme activity. The N supplementation at 1.1- 1.5 response index (RI) (248.14 μg PNP g-1 Soil hr-1 and 22.68 μg NH4-N g-1 Soil for 24 hrs) and 81-90 % SI (245.91 μg PNP g- 1 Soil hr-1 and 22.38 μg NH4-N g-1 Soil for 24 hrs) recorded significantly higher phosphatase and urease enzyme activity as compared to N omission treatment. Interaction of genotypes and different N management practices did not differ significantly. The correlation of soil enzymatic activity showed a very strong and positive association (r>0.90) with total nitrogen, phosphorous and potassium uptake at the mid flowering stage of the cotton crop. [ABSTRACT FROM AUTHOR]

In this study, we investigated the sorption–desorption behavior of imazamox (IMZ) and 2,4-DB (DB) in two typical acidic Mediterranean agricultural soils and the impact of these herbicides on culturable soil bacterial populations, enzyme activities and functional diversity when applied at concentrations higher than recommended doses (10×, 50×, 500×). Herbicide sorption was similar in both soils and IMZ was less retained compared to DB (~0.5 vs. 40 µg g−1 soil, respectively). IMZ desorption was remarkable (70–100%) while that of DB was more limited, i.e., ~40%. Three days after spiking (DAS), IMZ and DB significantly increased the number of soil-culturable heterotrophic bacteria, actinomycetes and Pseudomonas spp., soil respiration and the potential catabolic capacity of soil microbial communities. Soil dehydrogenase activity increased by ~56–70% in IMZ-treated soils while being reduced by ~33–41% in DB-treated ones. β-glucosidase activity showed a soil-dependent behavior, while the pattern of C source utilization suggested a change of soil microbial community structure after herbicide (especially DB) spiking. At 30 DAS, the herbicides’ impact on soil microorganisms, enzyme activity and functional diversity was still visible. Moreover, a toxic effect of DB (at 50× and 500×), but not IMZ, was recorded vs. Rhizobium sullae, the bacterial symbiont of Hedysarum coronarium. The obtained results indicated that IMZ and DB are poorly sorbed and highly desorbed by both soils. Moreover, at the tested concentrations, IMZ and DB can have short- and medium-term impacts on the microbial component and the related activity of the investigated soils, likely affecting a range of ecosystem services provided by soil microorganisms.

Soil contaminated with petroleum hydrocarbons has been considered as a serious problem for more than two decades, as it inhibits microbial population, soil enzymatic activity and exhibits abiotic stress in plants as well as affects their metabolites. In the present study, a novel and effective treatments for managing petroleum contaminated soil has been developed. The design treatments were grouped in five classes (T1, T2, T3, T4 and T5) which include petroleum contaminated soil, cow dung, cow urine and crude biosurfactant in various concentrations. After, 90 days of treatment the soils of each group were screened for microbial population dynamics, enzymatic activity, oil reduction assay, SEM and FTIR analysis. The treated soils were further employed for growing Brassica nigra L and targeted metabolomics based approach study was executed to demonstrate the effect of the treatments on the chlorophyll metabolites. The results revealed that treatments (T1, T2, T3 and T4) enhanced the microbial population dynamics and enzymatic activity of the soil with maximum 67% oil reduction in the treatment T1 (600 g Petroleum Contaminated Soil + 400 g Cow Dung + 200 ml Cow Urine + 50 ml crude Biosurfactant + 250 ml Water). Further, the results of growth parameters and targeted metabolomics based model study complemented the effectiveness of the design treatments as variation of growth parameters and chlorophyll metabolites were observed. Hence, the treatments and metabolomics model developed and can be applied commercially as an effective way for the restoration of petroleum contaminated wastelands .