NO3 Content Research Articles

The competition between Bidens pilosa and Setaria viridis alters soil microbial composition and soil ecological function

Bidens pilosa is recognized as one of the major invasive plants in China. Its invasion has been associated with significant losses in agriculture, forestry, husbandry, and biodiversity. Soil ecosystems play an important role in alien plant invasion. Microorganisms within the soil act as intermediaries between plants and soil ecological functions, playing a role in regulating soil enzyme activities and nutrient dynamics. Understanding the interactions between invasive plants, soil microorganisms, and soil ecological processes is vital for managing and mitigating the impacts of invasive species on the environment. In this study, we conducted a systematic analysis focusing on B. pilosa and Setaria viridis, a common native companion plant in the invaded area. To simulate the invasion process of B. pilosa, we constructed homogeneous plots consisting of B. pilosa and S. viridis grown separately as monocultures, as well as in mixtures. The rhizosphere and bulk soils were collected from the alien plant B. pilosa and the native plant S. viridis. In order to focus on the soil ecological functional mechanisms that contribute to the successful invasion of B. pilosa, we analyzed the effects of B. pilosa on the composition of soil microbial communities and soil ecological functions. The results showed that the biomass of B. pilosa increased by 27.51% and that of S. viridis was significantly reduced by 66.56%. The organic matter contents in the bulk and rhizosphere soils of B. pilosa were approximately 1.30 times those in the native plant soils. The TN and NO3– contents in the rhizosphere soil of B. pilosa were 1.30 to 2.71 times those in the native plant soils. The activities of acid phosphatase, alkaline phosphatase, and urease in the rhizosphere soil of B. pilosa were 1.98–2.25 times higher than in the native plant soils. Using high-throughput sequencing of the 16S rRNA gene, we found that B. pilosa altered the composition of the soil microbial community. Specifically, many genera in Actinobacteria and Proteobacteria were enriched in B. pilosa soils. Further correlation analyses verified that these genera had significantly positive relationships with soil nutrients and enzyme activities. Plant biomass, soil pH, and the contents of organic matter, TN, NO3–, TP, AP, TK, and AK were the main factors affecting soil microbial communities. This study showed that the invasion of B. pilosa led to significant alterations in the composition of the soil microbial communities. These changes were closely linked to modifications in plant traits as well as soil physical and chemical properties. Some microbial species related to C, N and P cycling were enriched in the soil invaded by B. pilosa. These findings provide additional support for the hypothesis of soil-microbe feedback in the successful invasion of alien plants. They also offer insights into the ecological mechanism by which soil microbes contribute to the successful invasion of B. pilosa. Overall, our research contributes to a better understanding of the complex interactions between invasive plants, soil microbial communities, and ecosystem dynamics.

Methane consumption under the influence of different nitrogen sources in a tropical soil ecosystem

In order to minimize methane (CH4) concentration in the atmosphere we need to better understand CH4 consumption in agricultural soils. Nitrogen application to agriculture is predicted to increase significantly in the coming years to meet food security needs. However, the interaction between soil nitrogen and CH4 consumption is poorly understood. Experiments were carried out to evaluate CH4 consumption under the influence of the three nitrogen sources comprising N2(at ambient+5% and ambient+10%),NO3-N (at 10 mM and 20 mM) and NH4-N (at 10 mM and 20 mM). CH4 consumption was evaluated at different CH4 concentrations and feeding cycles to validate the effect of nitrogen. Among different N sources, N2 stimulated CH4 consumption potential by about 1.11–1.71 times over that in the absence of additional nitrogen (control), while N in the form of both NO3 and NH4 inhibited CH4 consumption by 1.14–2.18 times than in the control. CH4 consumption rate increased with CH4 feeding cycles. The effect of N sources on CH4 consumption followed similar trends irrespective of the N rate added.N2 stimulated the abundance of both nifH and pmoA genes. Abundance of methanotrophs pmoA gene copies and nitrifiers amoA gene copies were more in NH4-Namended soil than NO3-N.Available NO3 content in soil increased 9–30% with CH4 driven N2 fixation. This study concludes that N2 stimulated CH4 consumption while nitrogen in the form of NO3 and NH4 inhibited CH4 consumption in a tropical vertisol.

Nitrate contamination in groundwater and its health implications in a semi-urban region of Titrol block, Jagatsinghpur district, Odisha, India

Nitrate (NO3−) in drinking water poses serious health risks worldwide. Exposure to ionic sources of NO3− pollution in groundwater and health risks to children and adults require management measures to be taken prior to the development of urban activities. Groundwater samples were collected from a semi-urban region of Titrol block, Jagatsinghpur district, Odisha, and analysed for chemical variables. The content of NO3− ranged from 2 to 92 mg/L with an average of 34.26 mg/L, in which 83.33% of the groundwater samples contained NO3− above 10 mg/L. This is the starting point of water pollution activity in water. Computed values of the Nitrate Pollution Index (NPI) varied from −0.40 to 8.20 with an average of 2.42. According to NPI, 16.67%, 16.67%, 10%, 13.33%, and 43.33% of groundwater samples were unpolluted, slightly polluted, moderately polluted, significantly polluted, and very significantly polluted, covering 1.45%, 6.07%, 27.43%, 37.46%, and 27.59% of the study region, respectively. The correlation of NO3− with well depth and other chemical variables indicated significant degradation of groundwater quality by agricultural activities, leading to vulnerability of health conditions. According to Chronic Health Risk (CHR), CHR varied from 0.063 to 3.067 (1.067) for children and 0.042 to 1.917 (0.712) for adults, with 56.67% and 23.33% of groundwater samples above the acceptable level of 1.0. They covered 59.57% and 6.49% of the study region, respectively. Therefore, careful planning of prevention methods is necessary to reduce the health risk of NO3−.This study contributes to UNDP's Sustainable Development goals 2030 for a healthy environment.

Leaching is the main pathway of nitrogen loss from a citrus orchard in Central China

Due to the high application rates and low utilization efficiency of inorganic nitrogen (N) fertilizer, conventional citrus orchards tend to cause N losses and extensive pollution. In order to address these issues, it is essential to identify the leading cause of N loss by citrus orchard N mass balance. In the present study, a two-year field experiment was performed on 4 different treatments (CK: no N fertilizer; CF: conventional N fertilizer; NR: 70% of conventional N fertilizer; OM: NR with organic manure) to quantify the pathways of N loss in citrus orchards in Hubei Province, China. Our findings revealed that leaching (17.0%) was the dominant N loss pathway in the conventional citrus orchard of central China, followed by runoff (2.9%), NH3 volatilization (2.3%), and N2O emission (0.5%). Reduced N fertilizer rates (−30.0%) led to a significant reduction in gaseous N loss (−34.9%), runoff N loss (−20.3%), and N leaching (−13.0%) via the reduced content of soil NH4+ and soil NO3-. Interestingly, the presence of organic manure reduced 15.2% of runoff N loss, 3.8% of N leaching and 6.9% of total N loss via reduced soil NO3-, but increased 39.6% of gaseous N loss via increased soil DOC. On the other hand, the low N fertilizer rates suppressed N uptake of citrus by reducing the content of soil NO3-, while organic manure promoted N uptake of citrus via the increased content of soil DOC. Overall, using organic manure as a substitute provides a better solution to fertilization for the citrus orchards in central China compared to reducing N fertilizer rates.

Solid-liquid phase equilibrium for the system ammonium polyphosphate-urea ammonium nitrate-potassium chloride-water at 273.2 K

Based on the dynamic method, a quaternary system of ammonium polyphosphate (APP)-urea ammonium nitrate (UAN, CO(NH2)2-NH4NO3)-potassium chloride (KCl)-H2O and its subsystems (APP-[CO(NH2)2-NH4NO3]-H2O, KCl-[CO(NH2)2-NH4NO3]-H2O and APP-KCl-H2O) were systematically investigated at the temperature of 273.2 K. Each ternary phase diagram contains one invariant point and three crystallization regions. The crystallization regions are: (1) (NH4)3HP2O7, (NH4)4P2O7 and ((NH4)3HP2O7 + (NH4)4P2O7) for APP-[CO(NH2)2-NH4NO3]-H2O diagram; (2) KCl, KNO3 and (KCl + KNO3) for KCl-[CO(NH2)2-NH4NO3]-H2O diagram and (3) (NH4)3HP2O7, KCl and ((NH4)3HP2O7 + KCl) for APP-KCl-H2O diagram. The quaternary phase diagram of APP-[CO(NH2)2-NH4NO3]-KCl-H2O has no quaternary invariant point but includes four solid phase crystallization regions, i.e., (NH4)3HP2O7, (NH4)4P2O7, KNO3 and KCl, in which the KNO3 region occupies the largest area. The maximum total nutrient content (N + P2O5 + K2O) existing as ionic forms in the APP-[CO(NH2)2-NH4NO3]-H2O, KCl-[CO(NH2)2-NH4NO3]-H2O, APP-KCl-H2O and quaternary systems is 44.70%, 32.86%, 45.56% and 46.23% (mass), respectively, indicating that the maximum nutrient content can be reached using raw materials of the corresponding systems to prepare liquid fertilizer. In the quaternary system, the content of NH4+-N ascends with the increase of the total nutrient content, while the contents of NO3--N and CO(NH2)2-N increase with elevated total N. This work can help optimize the operating parameters for the production, storage and transportation of liquid fertilizers.

Variations in Methanogenic and Methanotrophic Communities Resulted in Different Methane Emissions from Paddy Soil Applied with Two Types of Manure

Organic manure application is crucial for the maintenance and improvement of soil fertility. However, it inevitably results in increased paddy CH4 emissions, restricting the use of organic manure in the rice fields. In the present study, two kinds of manures, rapidly composted manure (RCM) and non-composted manure (NCM), were investigated through a 19-week greenhouse experiment, during which the dynamics of CH4 emission, soil parameters (DOC, acetate, NH4+, NO3−, and SO42−), and communities of methanogens and methanotrophs were simultaneously measured. The results showed that NCM significantly enhanced CH4 emission, while RCM decreased CH4 emission by 65.03%; there was no significant difference with the manure-free treatment. In order to well understand the methanogenic process, the seasonal CH4 flux was divided into two periods, namely Stage 1 (before drainage) and Stage 2 (after drainage), on the basis of CH4 emission intensity. The different CH4 production abilities among the three treatments could contribute to the varied CH4 emissions at Stage 1. The much higher soil DOC concentrations were observed in the manure-amended soils (NCM- and RCM-treatments), which could correspondingly lead to the relative higher CH4 emissions compared to the control during Stage 1. Furthermore, the increased methanogenic abundance and the shifted methanogenic archaeal community characterized by the functionally stimulated growth of Methanosarcina genus were observed in the NCM-treated soils, which could consequently result in a higher CH4 emission from the NCM treatment relative to the RCM treatment. As for Stage 2, apart from the significant decrease in soil DOC, the increased contents of soil NO3− and SO42−, especially with the RCM-treated soils, were also detected following the drainage, which might retard CH4 production. The lower CH4 emission at Stage 2 could also be attributed to the vigorous aerobic CH4 oxidations, especially in the RCM-treated soils. As a support, the amount of methanotrophs revealed an increasing trend during the late rice growth period, as did the predominance of the methylotrophy of Methylophilaceae species, which showed robust co-occurrence with methanotrophs, inferring interspecies cooperation in methane oxidation.

Physiological changes in tomato colonized by dark septate endophytic fungi

As is customary in mycorrhizae, the interaction between plant and dark septate endophytic (DSE) fungi can result in physiological changes in the host plant, which are still poorly understood. This study aimed to evaluate the physiological changes in tomato plants colonized by DSE fungi. Four DSE isolates previously identified through ITS phylogeny were inoculated on tomato seeds and compared to non-inoculated plants (control). Kinetic parameters (Vmax and Km) were calculated measuring the nitrate content in the nutrient solution. The contents of NO3--N, NH4+-N, amino-N, soluble sugars in the root, petiole, stem and leaf, and the contents of macronutrients in the shoot were determined. The plants inoculated with A101 and A105 exhibited (i) significant increases in the soluble sugar contents; (ii) increases in the contents of P, K, Mg and S; and (iii) increased dry biomass compared to control. The A103 inoculation was antagonistic when compared to the other treatments, leading to a higher influx of NO3--N in the plants, resulting in a higher amino-N and the lower soluble sugar content in the shoot. The physiological parameters of tomato varied depending on the inoculation, and the changes ranged from positive to negative depending on each isolate involved in the interaction.

Экологические проблемы развития восстановительных условий в почвах

Excessive moistening of soils leads to the development of restorative conditions in them, an increase in the mobility of Fe, Mn, Cu, a decrease in Eh of less than 400-300 mv, to the transition of NO3 to NH4, NH3, N2, to an increase in the gas phase of soils of CO2, H2S, methane. At the same time, negative consequences appear both in soils and in water and air environments. This has a negative effect on the vegetation cover of hydromorphic soils. The paper shows an increase in denitrification with excessive moistening of soils, a decrease in Eh, NO3 content, mobile phosphates, and a decrease in the ratio of mobile (Ca+Mg):(Fe+Mn), while there is also a change in the content of positively and negatively charged cation compounds in water, soil, and plants. Keywords: SOD-PODZOLIC SOIL, MEADOW-CHERNOZEM SOIL, ANAEROBIOSIS, GLUING, PROCESSES AND REGIMES

Sugarcane straw returning is an approaching technique for the improvement of rhizosphere soil functionality, microbial community, and yield of different sugarcane cultivars.

Sugarcane straw returned to the field has rapidly increased due to the bane on straw burning in China. Straw returning of new sugarcane cultivars has been practiced in the fields. Still, its response has not been explored on soil functionality, microbial community and yield of different sugarcane cultivars. Therefore, a comparison was made between an old sugarcane cultivar ROC22 and a new sugarcane cultivar Zhongzhe9 (Z9). The experimental treatments were: without (R, Z), with straw of the same cultivar (RR, ZZ), and with straw of different cultivars (RZ, ZR). Straw returning improved the contents of soil total nitrogen (TN by 73.21%), nitrate nitrogen (NO3 -N by 119.61%), soil organic carbon (SOC by 20.16%), and available potassium (AK by 90.65%) at the jointing stage and were not significant at the seedling stage. The contents of NO3 -N was 31.94 and 29.58%, available phosphorus (AP 53.21 and 27.19%), and available potassium (AK 42.43 and 11.92%) in RR and ZZ were more than in RZ and ZR. Straw returning with the same cultivar (RR, ZZ) significantly increased the richness and diversity of the rhizosphere microbial community. The microbial diversity of cultivar Z9 (treatment Z) was greater than that of cultivar ROC22 (Treatment R). In the rhizosphere, the relative abundance of beneficial microorganisms Gemmatimonadaceae, Trechispora, Streptomyces, Chaetomium, etc., increased after the straw returned. Sugarcane straw enhanced the activity of Pseudomonas and Aspergillus and thus increased the yield of sugarcane., The richness and diversity of the rhizosphere microbial community of Z9 increased at maturity. In ROC22, bacterial diversity increased, and fungal diversity decreased. These findings collectively suggested that the impact of Z9 straw returning was more beneficial than ROC22 on the activity of rhizosphere microorganism's soil functionality and sugarcane production.

On the significance of the activity of liver arginase and Kupffer cells in the development of secondary atherogenic dyslipidemia and the formation of thyroid status in rats with experimental peritonitis

Peritonitis is one of the most severe complications of various diseases and injuries of the abdominal organs. The diagnosis of peritonitis in a general sense implies any form and severity of inflammation of the peritoneum. Currently, the problem of peritonitis remains actual, despite the achievements of scientific and technological progress. So, despite the successes of modern surgery, the achievements of asepsis and antiseptics, the rather wide possibilities of antibacterial, infusion and detoxification therapy, the incidence of peritonitis and mortality from it remain at a high level. The aim of the study was to elucidate the significance of the activity of liver arginase and Kupffer cells in the development of secondary atherogenic dyslipidemia and the formation of thyroid status in rats with experimental peritonitis. It has been established that under conditions of experimental peritonitis in rats, the activity of liver arginase decreases, the content of NO3 – /NO2 – increases and the level of iodine-containing thyroid hormones in the blood decreases, secondary atherogenic dyslipoproteinemia develops. Liver arginase and Kupffer cells are involved in changes in the content of total cholesterol in the liver, total cholesterol, lipoprotein cholesterol, the level of iodine-containing hormones in the blood and body temperature in peritonitis. A decrease in the activity of Kupffer cells in peritonitis is accompanied by an increase in the level of triiodothyronine in the blood, a less pronounced decrease in the activity of liver arginase and a weakening of the development of characteristic changes in the content of total cholesterol in the liver, lipoprotein cholesterol in the blood and prevents the development of secondary dyslipoproteinemia. Depression of liver arginase in conditions of peritonitis aggravates changes in the content of total cholesterol in blood and liver lipoproteins, triiodothyronine in the blood and contributes to the development of secondary dyslipoproteinemia.

Influence of nitrogen stress on nitrate accumulation and yield of lettuce varieties

Relevance. Many authors note the existence of significant genotypic differences in the assimilation of nitrogen and the accumulation of nitrates by lettuce, point to the additive-dominant nature of the inheritance of the trait. The aim of the work was to evaluate the response of lettuce of various cultivars to mineral nutrition stress created against a nitrogen-deficient background (N0) and with an increased dose of nitrogen (N200).Material and Methods. In a microfield experiment on well-cultivated soddy-podzolic soil, a collection of lettuce varieties belonging to the main cultivated variety types was studied. The varieties differed in geographical origin, early maturity and morphological characteristics.Results. Differences in yield between varieties against the background of N200 were 4.5 times, and against the background of N0 – 5.7 times. Against an increased background of nitrogen nutrition, the highest yield – 2.22-2.64 kg/m2 was formed by the following varieties: All the Year, Quedlinburger Dickkopf, Berlin Yellow, Great lakes. Against a nitrogen-deficient background, Azart and Odessa Kucheryavets varieties stood out in terms of yield, which absorbed soil nitrogen better than others. The content of nitrates in lettuce plants of different varieties varied more strongly when grown on the background of N200 and ranged from 10.7 to 13.6 times (on average over 2 years – 11,2 times), on the control of N0 – 33 times. Varieties accumulating maximum NO3 under conditions of excess nitrogen nutrition were revealed. Lettuce Romaine (Lactuca romana) – 353 mg/kg and White paris cus (198 mg/kg) had a low content of NO3. The period of the maximum increase in biomass also corresponded to the maximum decrease in NO3 in plants. Power function equations were calculated to estimate the rate of change in biomass and NO3 content. The results indicate that there may be some scope for NO3 reduction in lettuce through cultivar selection or breeding.

Distribution fractions and potential ecological risk assessment of heavy metals in mangrove sediments of the Greater Bay Area.

The restoration of mangrove in coastal wetlands of China has been started since the 1990s. However, various pollutants, especially for heavy metals (HMs), contained in wastewater might present a significant risk to mangrove forests during the restoration. In this study, sediments of five typical mangrove wetlands with varying restoration years and management measures in the Greater Bay Area were collected to evaluate the distribution fractions and potential ecological risk of HMs. Cd (0.2-1.6mg/kg) was found in high concentrations in the exchangeable fraction (37.8-71.5%), whereas Cu (54.2-94.8mg/kg), Zn (157.6-332.6mg/kg), Cr (57.7-113.6mg/kg), Pb (36.5-89.9mg/kg), and Ni (29.7-69.5mg/kg) primarily presented in residual fraction (30.8-91.9%). According to the geo-accumulation index (Igeo) analysis, sediment Cd presented a high level of pollution (3 ≤ Igeo ≤ 4), while Zn and Cu were associated with moderately pollution (1 ≤ Igeo ≤ 2). Besides, high ecological risk of Cd was found in sediments of five mangroves, with risk assessment code (RAC) ranging from 45.9 to 84.2. Redundancy analysis revealed that the content of NO3--N was closely related to that of HMs in sediments and, pH value and NO3--N concentration affected the distribution of HMs geochemical fractions. High concentration of HMs in QA and NS sampling sites was caused by the formerly pollutants discharge, resulting in these sediments still with a higher HM pollution level after the plant of mangrove for a long period. Fortunately, strict drainage standards for industrial activities in Shenzhen significantly availed for decreasing HMs contents in mangrove sediments. Therefore, future works on mangrove conversion and restoration should be linked to the water purification in the GBA.

The migration and accumulation of typical pollutants in the growing media layer of bioretention facilities.

A series of complex physical and chemical processes, such as interception, migration, accumulation, and transformation, can occur when pollutants in stormwater runoff enter the growing media layer of bioretention facilities, affecting the purification of stormwater runoff by bioretention facilities. The migration and accumulation of pollutants in the growing media layer need long-term monitoring in traditional experimental studies. In this study, we established the Hydrus-1D model of water and solution transport for the bioretention facilities. By analyzing the variation of cumulative fluxes of NO3--N and Pb with time and depth, we investigated pollutant migration and accumulation trends in the growing media layer of bioretention facilities. It can provide support for reducing runoff pollutants in bioretention facilities. The Hydrus-1D model was calibrated and verified with experimental data, and the input data (runoff pollutant concentration) for the pollutant concentration boundary was obtained from the SWMM model. The results demonstrated that the cumulative fluxes of NO3--N and Pb increased with the passage of simulation time and depth of the growing media layer overall. From the top to the bottom of the growing media layer, the change rates of the peak cumulative fluxes of NO3--N and Pb were strongly linked with their levels in the runoff. An increase in rainfall decreased the content of NO3--N and Pb in the growing media layer, and this phenomenon was more obvious in the lower part of the layer.

Effects of flood inundation on biogeochemical processes in groundwater during riverbank filtration

Well fields along rivers withdrawing groundwater through riverbank filtration (RBF) are popular for urban water supply, due to their good performance in assurance for both water quantity and quality. However, RBF sites are susceptible to flood inundation, which has been found to cause increase of N, Fe, and Mn contents in groundwater and threatens water safety, but the geochemical processes have not been fully understood. To bridge this gap, in situ monitoring of hydrodynamics, hydrochemistry, and stable isotopes for river water and groundwater were employed in a RBF site, NE China, to investigate into the geochemical processes in groundwater in RBF sites under long-term inundation. The results indicated that during long-term inundation, recharge from river water increased significantly, and a large amount of O2, NO3− and organic carbon (OC) from oxidizing river water could recharge far-shore groundwater vertically, whereas less NH4+ were input from regional groundwater, leading to a high content of NO3− and low content of the NH4+ in the groundwater. Meanwhile, limited NH4+ would be produced through dissimilatory nitrate reduction to ammonium (DNRA) and mineralization of organic nitrogen (MON). Moreover, along the infiltration path, aerobic respiration and denitrification (DNF) occurred rapidly. CO2 generated from OC oxidization in the two processes enhanced the dissolution of carbonate minerals, which could be used to trace the oxidizing-reducing (O-R) interface between river water and groundwater. As indicated, the inundation can cause the O-R interface which usually distributed near shore to extend to the entire well field during inundation. In this situation, the redox condition of groundwater used to be suitable for SO42− reduction in non-inundation period decreases to the level favoring the reduction of Mn(IV)/Fe(III) oxides during inundation, and the process of Fe2+ precipitation by reacting with HS− is weaken as the inhabitation of SO42− reduction, leading to a significant increase in Fe2+, Mn2+, and As contents, putting well field groundwater at risk of contamination.

Tea biochar-immobilized Ralstonia Bcul-1 increases nitrate nitrogen content and reduces the bioavailability of cadmium and chromium in a fertilized vegetable soil

Pyrolytic biochar (PL-BC, pyrochar) and hydrothermal biochar (HT-BC, hydrochar) derived from branches and leaves of tea plants had different pH, electrical conductivity (EC), total carbon nitrogen content, BET surface area, total pore volume, average pore diameter, and functional groups. HT-BC had a larger specific surface area and more functional groups than PL-BC. Ralstonia Bcul-1 (R-B) was the dominant and functional bacteria in a fertilized vegetable soil supplemented with TBB-immobilized R-B (TBB + R-B). R-B vitality was more closely related to BET surface area, total pore volume, and functional groups of tea-based biochar (TBB: PL-BC and HT-BC). R-B was able to maintain high oxidase activity. R-B and TBB + R-B can increase the activities of urease and peroxidase in vegetable soil playing an essential role in the biotransformation of ammonium nitrogen (NH4+-N) and nitrate nitrogen (NO3−-N). TBB was able to simultaneously increase the content of NO3−-N and NH4+-N, and TBB + R-B also significantly increased NO3−-N content but decreased NH4+-N content in a fertilized vegetable soil. These results indicated that R-B promoted nitrification in the soil, i.e. conversion of NH4+-N into NO3−-N, by enhancing the activities of urease and peroxidase. R-B had high adsorption capacity for cadmium (Cd) and chromium (Cr) (Cd&Cr: Cd and Cr). Moreover, TBB + R-B was able to convert weak acid extractable and reducible Cd&Cr into a more stable residual fraction and oxidizable Cd&Cr. The overall effect of the treatments was to reduce plant uptake of Cd&Cr by cabbage. TBB + R-B significantly promoted R-B growth, changed inorganic nitrogen speciation, increased NO3−-N supply, reduced Cd&Cr bioavailability, and decreased plant tissue Cd&Cr content.

АБ УДЗЕЛЕ АРГІНАЗЫ ПЕЧАНІ І КЛЕТАК КУПФЕРА Ў РЭГУЛЯЦЫІ ЗМЕСТУ ХАЛЕСТЭРЫНУ Ў ПЕЧАНІ І ЛІПАПРАТЭІНАЎ КРЫВІ, УЗРОЎНЯ ЁДЗМЯШЧАЛЬНЫХ ГАРМОНАЎ ШЧЫТАПАДОБНАЙ ЗАЛОЗЫ І ТЭМПЕРАТУРЫ ЦЕЛА Ў ПАЦУКОЎ З ЭКСПЕРЫМЕНТАЛЬНЫМ ПЕРЫТАНІТАМ

Despite the successes of modern surgery, the achievements of asepsis and antisepsis, the rather wide possibilities of antibacterial, infusion and detoxifica-tion therapy, the incidence of peritonitis and mortality from it remain at a high level. The aim of the study was to elucidate the significance of the activity of liver arginase and Kupffer cells in the regulation of total cholesterol in the liver and blood lipoproteins, the level of iodine-containing thyroid hormones and body temperature in rats with experimental peritonitis. It has been established that under conditions of experimental peritonitis in rats, the activity of liver arginase decreases, the content of NO3–/NO2– increases and the level of iodine-containing thyroid hormones in the blood decreases, secondary atherogenic dyslipoproteinemia develops. A decrease in the activity of Kupffer cells in peritonitis is accompanied by an increase in the level of trii-odothyronine in the blood, a less pronounced decrease in the activity of liver arginase and a weakening of the development of characteristic changes in the content of total cholesterol in the liver, lipoprotein cholesterol in the blood and prevents the development of secondary dyslipoproteinemia. Depression of liv-er arginase in conditions of peritonitis aggravates changes in the content of to-tal cholesterol in blood and liver lipoproteins, triiodothyronine in the blood and contributes to the development of secondary dyslipoproteinemia.

Biochar derived from hydrolysis of sewage sludge influences soil properties and heavy metals distributed in the soil.

Sewage sludge contains a large number of nutrients and dangerous substances, when sludge was processed into sludge hydrochar that was added to the soil, which not only solve the problem of sludge disposal, but also amend the soil and fix pollutants in the soil. However, it was lack of report on the effect of the sludge hydrochar on soil compositions and soil microorganism community structures until now. In the present study, the hydrothermal carbonization method is used to prepare hydrochar from sewage sludge at temperatures of 180℃ and 240℃ at durations of 6h and 15h in this paper. The effects of the prepared sludge hydrochar on soil-derived dissolved organic matter (DOM), the content of total dissolved nitrogen (TDN) and NO3--N in soil, and the community structure of soil bacteria and fungi were evaluated. Furthermore, the change rules in heavy metal speciation in soils treated with sludge hydrochar were investigated. With the increase in the preparation temperature and dosage of sludge hydrochar, the main components of DOM changed from soluble microbial byproducts to fulvic acid-like and humic acid-like fractions through UV and fluorescence characterization. The sludge hydrochar prepared at low temperature could significantly increase the contents of TDN and NO3--N in the soil. Affected by sludge hydrochar, the dominant phylum of the bacterial community changed from Proteobacteria to Actinobacteria, and the dominant phylum in the fungal community did not change, but its relative abundance increased. Finally, the sludge hydrochar obtained when the carbonization time was 15h was more beneficial to reduce the total amount and available content of heavy metals in the soil. The study provides a basis for sludge hydrochar application for the soil amendment.

The activity of ammonia-oxidizing bacteria on the residual effect of biochar-compost amended soils in two cropping seasons

Ammonia-oxidizing bacteria (AOB) are vital in regulating nitrification in agricultural soils. Nevertheless, the knowledge of the AOB community's response to fortified and composted biochar application in the maize/soybean agroecosystem is scarce. This study examined the residual effects of a control soil (CNZ), biochar (BIZ), compost (CPZ), composted biochar (CBZ), and fortified biochar (FBZ) on the AOB community composition, soil chemical properties, and enzyme activities in 2018 and 2019 of a maize/soybean agroecosystem. The AOB community was unravelled using Illumina Miseq sequencing, and multivariate approaches were used to explain the data collected. In 2018, FBZ increased the content of NO3--N, while CPZ, CBZ, and FBZ improved total nitrogen (TN) in the soil. In 2019, CBZ and FBZ increased NO3--N content, while CPZ improved TN and NO2--N in the soil. Likewise, CPZ significantly differed from FBZ, CBZ, and BIZ in AOB richness, while CBZ significantly differed from BIZ in AOB diversity in 2019. Furthermore, distance-based redundancy analysis (db-RDA) and Spearman correlation showed a significant correlation with NH4+-N and NO2--N in 2018 and TN and NO3--N in 2019, while Nitrosomonas eutropha and Nitrosomonas nitrosa had the highest weighted degree in the co-occurrence network in both years. This research demonstrates that co-application of biochar with compost in the maize/soybean agroecosystem could result in changes in the AOB community structure.

Hydrogeochemical assessment and groundwater quality in a shallow aquifer: A case study of San Luis Potosí Valley, Mexico

The chemical composition of groundwater is the product of the evolution and incorporation of major ions, the product of natural hydrogeochemical processes or human interference that occurs in an aquifer. To establish the hydrogeochemical groundwater characteristics and suitability, 47 samples were collected from shallow wells in the study area. The objective was to determine the hydrogeochemical assessment of the groundwater in the shallow aquifer and establish the water quality and pollution associated with the dissolved organic matter in the San Luis Potosí sub-basin. The water quality assessment has been carried out by evaluating the physicochemical parameters such as temperature, pH, EC, TDS, and the main ions, which present the following trend: Ca2+>Na+>K+>Mg2+, HCO3− > SO42− > Cl− > NO3. The type of water in the area is mainly of four types: Ca–Na–HCO3–Cl (32%), Ca–Na–SO4–HCO3 (19%), Na–Ca–HCO3–Cl (13%), Ca–Na–HCO3–SO4 (11%). The content of NO3− (4.0–50.0 mg L−1), NH4+ (0.03–40.0 mg L−1), SO42− (20.0–276.0 mg L−1) y PO43− (0.01–45.5 mg L−1) indicate contamination that may come from inorganic and organic matter. Organic matter of anthropogenic origin was identified by 3D fluorescence. The results of this study demonstrate that the main processes that affect and control the chemical composition of the water in the shallow aquifer of SLP are silicate weathering, albite weathering, and reversible ion exchange.

Chamomile plant material effects on soil nitrogen dynamics and ammonia-oxidizers to mitigate greenhouse gas emissions from maize fields

Commonly, agricultural practices utilize urea as a nitrogen (N) source, which can lead to N losses to the environment. Application of urease inhibitors (UIs) or nitrification inhibitors (NIs) can mitigate these losses to some extent but not completely. A preliminary study showed that 2-Cyclopenten-1-one (CCO), an organic compound derived from chamomile (Chamomila recutita L.) can inhibit soil urease activity and also nitrification and therefore has the potential to act as a dual-function inhibitor for decreasing fertilizer-induced N losses and increasing N use efficiency. In this study, a field experiment was conducted to evaluate the effect of CCO on N transformations and NH3, N2O and CH4 emissions from soil, and monitor changes in the ammonia oxidizer amoA gene abundance. Three replicates of five fertilized treatments were included: Urea (fertilizer only), thiophosphoric triamide (NBPT) (a urease inhibitor), dicyandiamide (DCD) (a widely used synthetic nitrification inhibitor), NBPT combined with DCD, and CCO, along with an unfertilized control.The results indicated that, the ability of CCO to reduce N losses and improve maize yield was potentially superior to DCD, NBPT, or the combination of DCD and NBPT. Compared with the urea treatment, the addition of CCO significantly reduced urease activity and nitrification, which subsequently increased the content of NH4+-N and decreased the content of NO3--N in the soil during the maize growth period. Moreover, the cumulative NH3 and N2O emissions, global warming potential (GWP) and greenhouse gas intensity (GHGI) of the maize field were lowest from the CCO applied plots during the growth season, decreasing by 32.5 %, 21.94 %, 7.69 % and 20.92 %, respectively, compared to urea treatment. Notably, CCO application significantly reduced the abundance of ammonia-oxidizing archaea and bacteria in soil. These results suggest that CCO is effective for suppressing urease activity and the nitrification rate in soil and has the potential to be a novel naturally sourced dual-purpose inhibitor.