High Nitrogen Levels Research Articles

Identifying the difference in bacterial composition and life history strategies between high versus low nutrient soils

In this study, we aim to identify bacterial composition in soils treated with and without wood chips, as well as high levels and low levels of nitrogen. In order to do this, we used both culture dependent methods including plating, observing, and GenIII plates; as well as culture independent methods which include microbiome sequencing and EcoPlates. By doing this, we concluded that the bacterial communities differ between unamended and wood-chipped treated soils. Multiple differences were identified: rate of carbon consumption, bacterial diversity, rRNA gene copy number, and colony morphologies. Identifying the bacteria in wood-chipped soils will allow us to understand their effect on biogeochemical cycles, plant pathogens, and relationship with the trees (symbiotic/pathogen). Additionally, understanding the effect lower nitrogen levels have on the bacterial composition of soils can lead to reduction of synthetic fertilizer use, therefore lessening the environmental impact of nitrogen.

Effects of vapor pressure deficit combined with different N levels on tomato seedling anatomy, photosynthetic performance, and N uptake

Vapor pressure difference (VPD) is the main driving force of plant transpiration and the main factor of greenhouse environment regulation. Nitrogen is the main element of crop growth and development. It is significant to explore the regulation of VPD on nitrogen absorption and its effect on tomato photosynthesis. In this paper, using tomato as material, using an artificial climate chamber, the effect of VPD and nitrogen level coupling on nitrogen absorption and distribution, hydraulic characteristics, and photosynthetic characteristics of tomato was studied and analyzed. The optimal regulation of VPD and nitrogen was analyzed. Studies have shown that appropriately reducing the VPD can promote the absorption of nitrogen by plants. The increased surface area and volume of tomato roots and the increased activity of nitrogen assimilation-related enzymes were beneficial to nitrogen absorption and assimilation. Compared with high VPD (HVPD) plants, the leaf thickness and spongy tissue thickness of low VPD (LVPD) plants decreased, and the palisade/spongy tissue thickness ratio (P/S) increased; Leaf water conductance (Kleaf) increased with the increase of nitrogen level. The Kleaf at normal and high nitrogen plants increased by 4.00 % and 33.93 %, respectively, compared with HVPD plants of the same nitrogen level (significant difference at high nitrogen level) but significantly decreased at low nitrogen level. The decrease of spongy tissue thickness, the increase of palisade/sponge tissue, and the up-regulation of aquaporin expression were all beneficial to increasing Kleaf. Decreasing VPD and increasing nitrogen application under LVPD both increased specific leaf area (SLA). Compared with HVPD treatment, the photosynthetic rate of LVPD-treated plants increased by 7.06 % and 30.48 % at normal and high nitrogen levels, respectively.

Negative effects of fish cages on coral reefs through nutrient enrichment and eutrophication in Nha Trang Bay, Viet Nam

The potential impact of cage farming activities on nutrient enrichment of the coastal waters of Nha Trang bay, Viet Nam as investigated within a project financed by the Vietnam Academy of Science and Technology (VAST). Results show a very high level of nitrogen (N) in the studied area: the average content of dissolved inorganic nitrogen (DIN) was 177.4 ±6.0μg/l (range from 169.9 to 188.9μg/l), in which NO3-N accounts for the major proportion (average 152.9 ±1.9μg/l). The Redfield ratio (N/P) also showed values larger than 16 in almost all studied sites, indicating that phosphorus may be the limiting nutritional factor in these coastal waters. The TRIX indexes recorded for both the surface and bottom waters are within a range of about 5–6 (at high nutrient level); especially at sites under the cages and near the cage farming area. Cross-transplantation experiments with corals showed significant differences at different sites, particularly in relation to distance to fish cages. In comparison, the zooxanthellae densities of Acopora formosa in coral polyps indicated a rapidly reduced value after 31 days of exposure in the polluted areas. Strong side effects such as increased sedimentation as a result of fish farm activities can be detected on nearby coral reef. It is concluded that fish cage farming is negatively impacting coral reefs by being a point source of surplus nutrients.

Changes in Forest Conditions in a Siberian Larch Forest Induced by an Extreme Wet Event

The taiga forest, a semi-arid and nitrogen-limited ecosystem on permafrost, has changed under extreme wet events. This study aims to understand the changes that occurred in a larch forest in Eastern Siberia after the wet event of 2006–2007. In the summer of 2018, studies were conducted at the Spasskaya Pad Experimental Forest Station near Yakutsk, Russia, where a transect (60 m × 510 m) with 34 plots (30 m × 30 m) was set. It included intact sites and affected sites with different levels of forest damage, owing to the extreme wet event. We observed spatial variations in the normalized difference vegetation index (NDVI) calculated from Landsat satellite-observed data, and the foliar δ13C, δ15N, and C/N (carbon/nitrogen) ratio obtained from the needle samples of 105 mature larch trees. Our results reveal that the affected plots had a lower NDVI than the intact plots, resulting from a difference in tree stand density. In addition, the stand density is suggested to be a controlling factor in the spatial variations in the foliar C/N and δ13C values based on their significant relationships with the NDVI in June. We concluded that the larch trees from the regenerating forests in the affected areas have a higher nitrogen level and light availability (relatively low C/N and high δ13C) because of the slight competition for resources, owing to a low-stand density. This may lead to further succession of the larch forests after the extreme wet event.

Community characteristics of autotrophic CO2-fixing bacteria in karst wetland groundwaters with different nitrogen levels.

Karst wetlands are important in the global carbon and nitrogen cycles as well as in security of water resources. Huixian wetland (Guilin) is the largest natural karst wetland in China. In recent years, groundwater nitrogen pollution has increasingly affected the wetland ecosystem integrity due to anthropogenic activities. In this study, it was hypothesized that autotrophic microbial diversity is impacted with the advent of pollution, adversely affecting autotrophs in the carbon and nitrogen cycles. Autotrophic microbes have important roles in abating groundwater nitrogen pollution. Thus, it is of great significance to study the characteristics of autotrophic bacterial communities and their responses to environmental parameters in nitrogen-polluted karst groundwaters. The abundances of the Calvin–Benson cycle functional genes cbbL and cbbM as well as the autotrophic CO2-fixing bacterial communities were characterized in the karst groundwater samples with different levels of nitrogen pollution. The cbbM gene was generally more abundant than the cbbL gene in the groundwater samples. The cbbL gene abundance was significantly positively correlated with dissolved inorganic nitrogen (DIN) concentration (P < 0.01). In the autotrophic CO2-fixing bacterial communities, Alphaproteobacteria, Betaproteobacteria, and Gammaproteobacteria of the phylum Proteobacteria were predominant. At the genus level, Rubrivivax and Methylibium were the dominant cbbL gene containing genera, while Halothiobacillus and Endothiovibrio were the dominant genera for the cbbM gene. The abundance of autotrophic CO2-fixing bacterial communities increased but their diversity decreased with the inflow of nitrogen into the karst groundwater system. The community structure of autotrophic CO2-fixing bacteria in the groundwaters was also significantly affected by environmental factors such as the carbonic anhydrase (CA) activity, dissolved inorganic carbon (DIC) concentration, temperature, and oxidation-reduction potential (ORP). Nitrogen inflow significantly changed the characteristics of autotrophic CO2-fixing bacterial communities in the karst groundwaters. Some key genera such as Nitrosospira and Thiobacillus were clearly abundant in the karst groundwaters with high nitrogen levels. Their respective roles in nitrification and denitrification impact nitrogen removal in this ecosystem. The findings in this study provide an important reference for biological abatement of nitrogen pollution in the karst groundwater system.

Microphytobenthos as a source of labile organic matter for denitrifying microbes

Nitrogen loads in natural waters remain elevated in populated and agricultural areas with serious impact on estuarine and coastal ecosystems. Intertidal sediments can play a significant role in attenuating the high nitrogen levels in water via microbial nitrate reduction, in general dominated by denitrification. These heterotrophic processes are heavily mediated by both the quantity and quality of organic matter available. Benthic microalgae were experimentally investigated as organic carbon source for denitrifying microbes in intertidal mudflat sediments from the Seine Estuary (France). Dry microphytobenthos (including algae and their extracellular polymeric substances) were added to sediments and nitrate reduction rates were monitored over a two-week period using anoxic controlled flow-through reactor approach. Our results show that microphytobenthos addition resulted in significantly higher nitrate reduction (67–332% increase), highly related to the added amount of microphytobenthos. Moreover, increase of the low molecular weight carbohydrates consumption (11–39%) highlight the measurable contribution of extracellular polymeric substances to the carbon consumption during nitrate reduction. The addition of microphytobenthos increased the abundance of nitrite reductase genes, especially those encoding the nirS gene (43–152% increase) while nitrous oxide reductase genes (nosZ gene) remained constant. Microphytobenthos appeared to favor complete denitrification as suggested by an increase in nirS and a decrease in clade II nosZ gene copy numbers. This study confirms experimentally the assumption that microbes use microalgae and particularly labile extracellular polymeric substances as a carbon substrate for nitrate reduction. These results reinforce the impact played by microphytobenthos in intertidal mudflats by highlighting their role on denitrifying microbes and nitrate removal from water.

Seaweed Oligosaccharide Synergistic Silicate Improves the Resistance of Rice Plants to Lodging Stress under High Nitrogen Level

The objective of this study was to determine the effect of seaweed oligosaccharide synergistic silicate (Si) fertilizer (SOSSiF) on rice resistance to lodging stress. The results showed that a spraying SOSSiF decreased apparent lodging index and enhanced rice yield significantly under a high N level. The spraying test indicated that the apparent lodging rate of rice was the lowest when SOSSiF was sprayed for four times, and the dosage was 45 kg/ha each time. Morphological and anatomical analysis indicated that SOSSiF decreased plant height and the lower internode length of ZCSM and increased culm cross-sectional area and wall thickness of JNSM significantly compared with the control. Furthermore, SOSSiF enhanced bending strength of rice culm by 38.8% to 63.6%, and reduced lodging index by 36.8% to 42.6%. Chemical component analysis found that SOSSiF elevated the contents of soluble sugar, cellulose, Si, and lignin in the culms of ZCSM and JNSM. Correlation analysis revealed that the lodging index was positively correlated with the length of the lower internode, and was negatively correlated with culm bending strength and culm thickness. The above results suggested that spraying SOSSiF elevates culm contents of Si and lignin and enhances bending strength, thus improving rice lodging resistance and production.

Effects of rising VPD on the nutrient uptake, water status and photosynthetic system of tomato plants at different nitrogen applications under low temperature

In winter and spring, the low-temperature and high-humidity environment of greenhouses in China and some locations are not suited for the development of tomatoes, which is sensitive to cold. At low temperature circumstances, the plant growth is slow, and the water transpiration ability is weak. The study tried to increase the vapor pressure deficit (VPD) by decreasing the humidity to observe if it can promote plant transpiration, which in turn facilitates nutrient absorption conveyed by the water, or it directly influences plant development through the alteration of the plant morphological structure. Two VPD levels (high VPD, HVPD; low VPD, LVPD) and three N supply gradients (low N level, LN; normal N level, NN; high N level, HN) were set in a climate chamber for 30 days test. We observed the physiological alterations of plants. The results revealed that biomass of low nitrogen, normal nitrogen and high nitrogen of HVPD plants decreased by 22.54%, 40.75% and 10.31%, respectively, compared with LVPD-treated plants. The palisade/spongy tissue ratio in leaves of HVPD plants decreased at normal and high nitrogen levels. Under HVPD conditions, the stomatal length and width increased, but its density decreased; the electron transfer and photochemical efficiency of the photosystem reaction center reduced. At low, normal and high nitrogen concentration, the photosynthetic rate of HVPD plants was 17.29%, 30.18% and 15.15% lower than that of LVPD plants. For HVPD plants, compared with LVPD plants, K+ absorption under LN increases significantly; nutritional absorption with HN treatment reduced significantly; the absorption of trace elements was also lower than LVPD plants. It revealed that even within the theoretically suitable VPD range for plant growth, rising VPD cannot achieve the purpose of improving nutrient absorption and stimulating growth. It needed to be examined according to certain environmental circumstances. In addition, the promotion impact of increasing N fertilizer was restricted, and it may not be favorable to plant development. At low nitrogen, LVPD treated plants thrived nicely, compared with HVPD treated plants. The investigation revealed that the optimal growth treatment at low temperature was LVPD+NN treatment.

Assessment of the Spatial Distribution and Mapping Soil Physico-Chemical Properties of Nalgad Municipality, Jajarkot, Nepal

A detailed soil inventory study using Global Positioning System (GPS) and Geographical Information System (GIS) was conducted in Nalgad Municipality of Jajarkot, Nepal in 2019. A preliminary reconnaissance survey during pre–field activities and detail field work was carried out to study the soil type and physico-chemical properties based on the soil pit. A total of 51 soil pits were taken in the field representing varied micro topography. Soil Sample pits covering all the units were dug based on the interpreted soil map, topographical map, ZY-3 Satellite imagery for determination of soil profile. Soil classification of the area was done based on the USDA soil taxonomy and the dominant soil orders found in the region were Entisols (15.13 %) and Inceptisols (83.60%). A total of 51 geo-referenced composite soil samples from a depth of 0-20 cm was collected from each pit and analyzed in laboratory for texture, soil pH, soil organic matter, total nitrogen, available phosphorus and exchangeable potassium. Majority of the soil are loam and loamy sand type. There is very low to high level of organic matter present in the study area with more proportion of land under high range of organic matter (64.98%). Total Nitrogen content in soil of the study area ranges from very low to very high level with high level of Nitrogen (65.51%) in major proportion. Low to very high level of available phosphorous content was found in the study area with the dominance of very high level of phosphorous (71.40%). Exchangeable Potassium level in the study area is very high to low. Around 42% land have very high level of potassium. From the soil test result, major nutrients status in soil were found to be good but integrated land management practices should be encouraged for improving land productivity. The generated soil maps may be helpful to stakeholders for planning, monitoring and evaluating the soil status for effective agricultural production.

Compost Addition Attenuates the Negative Impacts of High Soil Mineral Nitrogen Levels on Rhizosphere Microbial Characteristics and Enhances Cucumber Growth in Monoculture Systems.

Due to the increase in the human population, it is necessary to seek efficient methods of increasing crop productivity and, simultaneously, sustaining the soil. One way is to grow high demand crops continuously without rotating with other crops. This practice is often accompanied by increased rates of fertilizer application that can affect efficient nitrogen (N) cycling in the plant rhizosphere soil which, in turn, affects both plant growth and environmental pollution. In the present study, twelve various cucumber soils were selected from monoculture systems presenting different cropping years and divided into two groups including soils with relatively high mineral N (HMN) content (N > 100 mg kg−1 soil) and those with a lower mineral N (LMN) content (N < 100 mg kg−1 soil). All soils were amended with the addition of compost alone or in combination with bacterial inoculation to evaluate their effects on plant growth, microbial numbers, N mineralization, and N cycling genes. In general, the HMN soils increased (p < 0.05) net N mineralization (NNM) but did not statistically (p > 0.05) affect plant biomass compared to the LMN soils; however, compost addition increased both NNM and plant biomass in the HMN soils. In addition, the HMN soils had higher fungal pathogen numbers (FPNs) but lower total microbial biomass (TMB) and bacterial numbers (BNs) compared to the LMN soils; however, compost addition decreased FPNs but increased TMB and BNs in the HMN soils (all p < 0.05). Plant biomass was positively related to TMB, BN and NNM but was negatively related to FPN (all p < 0.05). In summary, compost addition reduced the high mineral N levels’ adverse effects on the rhizosphere soil and plant growth.

Effects of Photovoltaic Solar Farms on Microclimate and Vegetation Diversity

The need for energy and the increasing importance of climate change mitigation are leading to a conversion from conventional to renewable energy sources. Solar photovoltaic (PV) power has seen the most significant increase among all renewable energy sources. However, most of these installations are land-based, significantly changing global land use (LU). The real impacts, whether positive or negative, are poorly understood. This study was undertaken to have a better understanding of the impacts of solar parks on the microclimate and vegetation dynamics. First, different solar parks were visited to take measurements of the surface temperature (Tsurf), photosynthetic active radiation (PAR), air temperature (Tair), and humidity (RH) to quantify the microclimate and perform a vegetation relevé. The measurements were taken at different positions: underneath, in between, and outside solar panels. For vegetation, the data were first converted to diversity indices, which in turn contributed to a multi-indicator land use impact assessment that evaluated effects on vegetation, biodiversity, soil and water. Solar parks had clear effects on microclimate: if the panels were high enough from the ground, they could lower the Tsurf by providing shade and enough airflow. Additionally, the multidimensional functional diversity (FD) analysis of the vegetation indicated that there was less light at a higher humidity and lower temperature underneath the panels. Interestingly, the species underneath the panels also preferred a lower pH and a higher nitrogen level. Finally, the land use impact assessment found that the total land use impact for a wheat field was higher than that of the solar park, which suggests that the conversion of conventional intensive agriculture to a solar park would be beneficial.

Distribution of Vanadium in the Surficial Sediments of Prydz Bay, Indian Sector of the Southern Ocean

ABSTRACT The study was carried out in seven stations to assess concentration levels of Vanadium (V) in sediments of the Prydz Bay, Indian sector of the Southern Ocean during the austral summer season. Sediment analysis showed that V concentration on the eastern side was extensively higher than on the western side of Prydz Bay. A significant observation was the high concentration of V concentration in fine sediment fraction than in total metal fraction. Vanadium concentration level on the western side varied from 19.4 to 45.5 mg/kg while it was 40.9–65.8 mg/kg on the eastern side of Prydz Bay. The prevailing petroleum-related activities coupled with fuel combustion processes at various research stations in the Antarctic subcontinent and the influence of sea ice cover interaction could be the reason for the high V concentration on the eastern side of Prydz Bay. A significant spatial variation in textural characteristics, elemental composition, and total organic carbon was observed with high concentration levels of total organic carbon (TOC), total nitrogen (TN), and total hydrogen (TH) in the eastern part of Prydz Bay. The statistical analysis revealed a strong positive correlation of V concentration with governing factors at p < .01 level.

Biogas potential of cup plant and willow-leaf sunflower biomass

Perennial herbaceous crops (PHC) are increasingly often perceived as a competitive biomass source or as a co-substrate for biogas plants. The aim of the study was to determine the dry biomass yield, the biogas and methane production efficiency, potential energy yield and economic analysis for two PHC species, depending on the fertilisation type and nitrogen level in three successive cultivation years. The mean dry matter yield of Silphium perfoliatum was significantly higher (by 19.4%) compared to the mean yield of Helianthus salicifolius. The application of organic (digestate) and mineral fertilisers and a higher nitrogen level have significantly contributed to increasing dry matter yield compared to the plots without fertilisation. However, fertilisation have no significant impact on the biogas or methane efficiency. The highest biogas efficiency for S. perfoliatum and H. salicifolius biomass was 372.8 m3 Mg−1 DM and 280.9 m3 Mg−1 DM, respectively. The biogas, methane and energy potential yield of S. perfoliatum was significantly higher (over 50%) compared to the values of H. salicifolius. Meanwhile, the potential income from energy generation from S. perfoliatum was higher by 482%. Therefore, S. perfoliatum proved to be a more prospective PHC species as a biomass source for biogas plants.

Effects of Strigolactone on Torreya grandis Gene Expression and Soil Microbial Community Structure Under Simulated Nitrogen Deposition.

Nitrogen enters the terrestrial ecosystem through deposition. High nitrogen levels can affect physical and chemical properties of soil and inhibit normal growth and reproduction of forest plants. Nitrogen modulates the composition of soil microorganisms. Strigolactones inhibits plant branching, promotes root growth, nutrient absorption, and promotes arbuscular fungal mycelia branching. Plants are subjected to increasing atmospheric nitrogen deposition. Therefore, it is imperative to explore the relationship between strigolactone and nitrogen deposition of plants and abundance of soil microorganisms. In the present study, the effects of strigolactone on genetic responses and soil microorganisms of Torreya grandis, under simulated nitrogen deposition were explored using high-throughput sequencing techniques. T. grandis is a subtropical economic tree species in China. A total of 4,008 differentially expressed genes were identified in additional N deposition and GR24 treatment. These genes were associated with multiple GO terms and metabolic pathways. GO enrichment analysis showed that several DEGs were associated with enrichment of the transporter activity term. Both additional nitrogen deposition and GR24 treatment modulated the content of nutrient elements. The content of K reduced in leaves after additional N deposition treatment. The content of P increased in leaves after GR24 treatment. A total of 20 families and 29 DEGs associated with transporters were identified. These transporters may be regulated by transcription factors. A total of 1,402,819 clean reads and 1,778 amplicon sequence variants (ASVs) were generated through Bacterial 16S rRNA sequencing. Random forest classification revealed that Legionella, Lacunisphaera, Klebsiella, Bryobacter, and Janthinobacterium were significantly enriched in the soil in the additional N deposition group and the GR24 treatment group. Co-occurrence network analysis showed significant differences in composition of soil microbial community under different treatments. These results indicate a relationship between N deposition and strigolactones effect. The results provide new insights on the role of strigolactones in plants and composition of soil microorganisms under nitrogen deposition.

Decoy Receptor 3 Suppresses T-Cell Priming and Promotes Apoptosis of Effector T-Cells in Acute Cell-Mediated Rejection: The Role of Reverse Signaling

BackgroundDecoy receptor 3 (DcR3) belongs to the tumor necrosis factor (TNF) receptor superfamily and neutralizes TNF ligands, including FasL and TRAIL, to prevent T activation during T-cell priming. However, the cellular mechanisms underlying acute cell-mediated rejection (ACMR) remain unknown.MethodsWe generated DcR3 transgenic (Tg) mice and mice with high DcR3 expression (HDE) to study both in vivo and in vitro. FasR RNA knockdown in immortalized CD4+CD8+ T-cells was used to survey the role of DcR3 on FasR/Fas-associated protein with death domain (FADD)/caspase 8 pathway and its cross-link to TNF receptor-associated factor 1 (TNFR1)-associated death domain protein (TRADD) in suppressing TNFR1. TNF/TRADD knockout mice were used to show the importance of TNF adaptor protein.ResultsDcR3.Fc suppressed C57BL/6 female T-cell activation and transformation into CD4+CD69+, CD4+CD44+, and CD4+CD25+Foxp3+ when compared with isotype IgG1 and its co-treatment with FasL/TRAIL after exposing to bone marrow-derived dendritic cells (BMDCs) that carried alloantigen with male H-Y and minor antigenic determinant. Interleukin-17 and interferon-γ productions by BMDC-activated T-cells were lowered after co-treating with DcR3.Fc. DcR3.Fc induced effector T-cells (Teffs) and was susceptible to FasR-mediated apoptosis through the FADD/TRADD/caspase 8 pathway. After exposing to DcR3.Fc, TRADD was silenced, likely turning down the inflammatory response. The systemic effects of DcR3 Tg mice and HDE phenotype induced by the promoter of cytomegalovirus not only attenuated ACMR severity but also ameliorated the high serum creatinine and blood urea nitrogen levels even with high T-cell exposure frequencies. Besides this, DcR3 has minor biological effects on both MHC-matched and MHC-mismatched models.ConclusionsHigh DcR3 doses protect renal tubular epithelial cells from acute T-cell attack during the T-cell priming stage via interfering with TNF ligand-mediated reverse signaling and possibly promoting Teff apoptosis through FasR upregulation. Our findings supported that the decoy receptor is involved in T-cell modulation in kidney transplant rejection.

Diff erent Levels of Nitrogen Fertilizer in Nursery Stage Positively Aff ect the Activity of Defense-related Enzymes and Resistance of Tobacco Plant to Phytophthora nicotianae

Black shank caused by Phytophthora nicotianae is a serious threat to the production of better-quality fl ue-cured tobacco. Protein’s are executors of plant functions and most disease resistance mechanisms in plants are related to differential expression of proteins. In our previous study, 17 different proteins induced by P. nicotianae were screened out through proteomics analysis. In this study, we evaluated the effect of three different levels of nitrogen fertilizer (High, medium, and low) at the seedling stage on the expression of these proteins, physiological response of fl ue-cured tobacco, and occurrence of black shank disease. Results of this study showed that before and after inoculation of P. nicotianae, the activity of defense-related enzymes except for MDA contents in tobacco plants grown under low- nitrogen level was higher than tobacco plants grown under the high-nitrogen level at seedling stage. Through analysis of 17 different proteins, we found the expression of 12 proteins (three proteins involved in photosynthesis, six proteins involved in oxidative phosphorylation, one protein involved in tricarboxylic acid cycle, one heat shock protein, and one 14-3-3 protein) were up-regulated in tobacco seedlings raised under low nitrogen level. However, the expression of fi ve pathogenesis-related proteins was not detected. This study highlights the effect of effi cient use of nitrogen fertilizer during the nursery growing stage for producing healthy tobacco seedlings. It is concluded that a proper supply of nitrogen fertilizer at the seedling stage ensures the quality production of tobacco seedlings and reduces the incidence of black shank disease.

Impact of inorganic nitrogenous fertilizers and FYM combinations on plant height at various phases of rice growth and combinations on number of tillers per hill at various stages of effective tillers per hill during rice harvest (Oryza sativa L.)

A pot culture experiment entitled “Impact of inorganic nitrogenous fertilizers and FYM combinations on plant height at various phases of rice growth and combinations on number of tillers per hill at various stages of effective tillers per hill during rice harvest (Oryza sativa L.)” was conducted at Institute of Agricultural Sciences farm, Siksha ‘O’ Anusandhan (Deemed to be University), Bhubaneswar Odisha. on sandy loam soil during kharif 2018-2019. The experiment consisted of eight treatments viz. T1-Control, T2- 50% RDF, T3-50% RDF + FYM @ 5 t ha-1, T4-75% RDF, T5-75% RDF + FYM @ 5 t ha-1, T6- 100% RDF ( NPK 80:40:40), T7-100% RDF + FYM @ 5 t ha-1 and T8-150% RDF. The experiment was laid out in a Randomized Block Design with three replications. The results revealed that highest and significant values were recorded with respect to growth parameters i.e., plant height, number of tillers per hill, effective tillers per hill and yield attributes i.e., number of panicles per hill, panicle length, number of filled grains 1000 seed weight (test weight) in the treatment that received 100% RDF + FYM @ 5t ha-1. Combination of FYM (5 t ha-1) with lower levels of RDF (50 and 75% RDF) also registered higher increase in the above parameters as compared to the application of inorganic fertilizers alone with the corresponding levels. Grain and straw yields followed the same trend as that of growth parameters and at higher levels of nitrogen in the inorganic form (150 % RDF) the values of the various parameters including grain and straw yield were significantly lower than the treatment where 100% RDF +FYM @ 5 t ha-1was applied.. More nutrient content (N, P, K) in grain and straw was observed with the application of 100% RDF + FYM @ 5t ha-1 as compared with 100 and 150% RDF. With the combined application of 100 percent RDF as an inorganic source and 5tha-1 FYM as an organic source, improvements in physico-chemical characteristics such as organic carbon, bulk density, porosity, and accessible macro nutrients (N,P,K) were found.

Bacterial composition and inferring function profiles in the biofloc system rearing Litopenaeus vannamei postlarvae at a low salinity

This study investigated the bacterial composition and inferring function profiles in the biofloc system rearing Litopenaeus vannamei postlarvae (PL) at a low salinity condition. PL (~ stage 15) were stocked in four parallel tanks filled in water with a salinity of 5.0‰ at a density of 4000 individuals per m3 for a 28-days culture experiment, during which glucose was added as a carbon source with a C:N of 20:1. At the end of the experiment, water was sampled from each tank and pooled to extract microbial DNA for high-throughput sequencing of the V3-V4 region of the 16S rRNA gene. Results showed that the bacterial community at 28 d was dominated by phyla of Proteobacteria (45.8%), Bacteroidetes (21.1%), Planctomycetes (13.5%), Chlamydiae (10.3%), and Firmicutes (6.8%). A proportion of 81% inferring KEGG functions of this bacterial community is associated with metabolism. Among functions relating to nitrogen metabolism, 48.5% were involved in converting ammonia to glutamate. Still, the proportion of those engaged in transformation among ammonia, nitrite, and nitrate was 18.0%, inferring higher protein-synthesis but lower inorganic nitrogen-transformation capacities of the bacterial community. At the same time (28 d), high levels of total nitrogen (231.3±6.0 mg L-1) and biofloc (127.0±63.0 mL L-1) but low concentrations of ammonia (0.04±0.01 mg L-1), nitrite (0.2±0.1 mg L-1) and nitrate (12.9±2.5 mg L-1) were observed. The results supply a novel insight for understanding bacterial community function in the biofloc system nursing L. vannamei PL at low salinity.

Recurrent acute kidney injury in elderly patients is common and associated with 1-year mortality.

Acute kidney injury (AKI) is common among elderly patients after a first hospitalized AKI. Patients who recover are at risk for recurrence, but recurrent geriatric AKI is not well-studied. This was a retrospective, 12-month cohort study using data from the National Clinical Research Center for Geriatric Diseases. Recurrent AKI was defined as a new spontaneous rise of ≥ 0.3mg/dl (≥ 26.5µmol/L) within 48h or a 50% increase in serum creatinine (Scr) from the baseline within 7days after the previous AKI episode. The outcome measured was 12-month mortality. Among 1711 study patients, 652 developed AKI. Of the 429 AKI survivors in whom recovery could be assessed, 314 patients recovered to their baseline renal function, and 115 patients developed chronic kidney disease (CKD). Of the group that recovered renal function, 90 patients (28.7%) subsequently developed recurrent AKI, while 224 (71.3%) did not. Of the 429 survivors with AKI, 103 patients (24.0%) died within 12months. Multivariate logistic regression analysis revealed that recurrent AKI was significantly associated with coronary disease (odds ratio [OR = 2.008; 95% confidence interval [CI] 1.024-3.938; P = 0.042), a need for mechanical ventilation (OR = 2.265; 95% CI 1.267-4.051; P = 0.006) and high blood urea nitrogen levels (OR = 1.036; 95% CI 1.002-1.072; P = 0.040) at the first AKI event. Kaplan-Meier curves showed the 12-month survival of patients with non-recurrent AKI was better than that of patients with CKD, and survival of patients with recurrent AKI was worse than that of patients with CKD (log rank P < 0.001). In the multivariate Cox regression analysis, mortality at 12month was higher in the patient with recurrent AKI as compared with those with a single episode (HR = 3.375; 95% CI 2.241-5.083; P < 0.001). Recurrent AKI is common among elderly patients who recovered their renal function post-AKI and is associated with significantly higher 12-month mortality compared with CKD patients.

Packed activated carbon particles triggered a more robust syntrophic pathway for acetate oxidation-hydrogenotrophic methanogenesis at extremely high ammonia concentrations

To date, the anaerobic digestion (AD) of chicken manure has been difficult because of the inhibition caused by high ammonia nitrogen levels. In this study, granular activated carbon (GAC), zeolite, and medical stone (MS) were added to improve dry AD of chicken manure. The semi-continuous processes amended with GAC were stable throughout the experiment despite the presence of extremely high NH4+-N (∼11 500 mg L−1) and NH3–N (∼2350 mg L−1) levels. By adding GAC, the methane yield increased from 0.115 L g−1 VS in phase I to 0.128 L g−1 VS in phase III. The methane yield of zeolite group, MS group and control group decreased from ∼0.041 to 0.098 L g−1 VS in phase I to ∼0.005–0.012 L g−1 VS in phase III. The addition of zeolite improved dry AD during the early stage, but there was no improvement when MS was added. Different hydrolysis efficiency of macromolecular compounds and GAC adsorption of ammonium contributed to the improved biogas production, but the key reason for the improvement was promotion of the syntrophic acetate oxidation-hydrogenotrophic methanogenesis pathway. In contrast to previous studies, the GAC was not lost along with the digestate discharge because the activated carbon was packed in nylon bags with holes.