Nitrification and Denitrification Potentials of Soil in Liaohe Estuary Wetland

2014 ◽  
Vol 675-677 ◽  
pp. 71-74
Author(s):  
Ying Xiao ◽  
Ji Song Yang
Keyword(s):  
Incubation Period ◽  
Exponential Decay ◽  
Nitrogen Cycle ◽  
Surface Soil ◽  
Significant Difference ◽  
Different Depths ◽  
Nitrification And Denitrification

Nitrification and denitrification plays an important role in the nitrogen cycle in wetlands. The nitrification and denitrification potentials of soil from different depths (0-40 cm) in Liaohe estuary wetland were studied with laboratorial batch incubation for three weeks. The results showed that the percent of nitrification and denitrification in soil at different depth were about 25-40% and 31-63% of soil total added nitrogen over three weeks, respectively. Both the denitrification and nitrification of soil at different depth showed an exponential decay trend over the incubation period. The corresponding rates were 0.013–0.021 mg·kg-1·d-1and 0.017–0.057 mg·kg-1·d-1. The value of surface soil (0-5cm) was significant higher than that of the subsoil (5-40 cm) (p< 0.05) and there was no significant difference between values of the subsoil (p> 0.05).

scholarly journals Assessment of Seasonal Variability in Soil Nutrients and Its Impact on Soil Quality under Different Land Use Systems of Lower Shiwalik Foothills of Himalaya, India

2021 ◽  
Vol 13 (3) ◽  
pp. 1398
Author(s):  
Tavjot Kaur ◽  
Simerpreet Kaur Sehgal ◽  
Satnam Singh ◽  
Sandeep Sharma ◽  
Salwinder Singh Dhaliwal ◽  
...  
Keyword(s):  
Land Use ◽  
Soil Quality ◽  
Surface Soil ◽  
Sandy Loam ◽  
Monsoon Season ◽  
Soil Layer ◽  
Seasonal Effects ◽  
Land Use Systems ◽  
Post Monsoon ◽  
Significant Difference

The present study was conducted to investigate the seasonal effects of five land use systems (LUSs), i.e., wheat–rice (Triticum aestivum—Oryza sativa) system, sugarcane (Saccharum officinarum), orange (Citrus sinensis) orchard, safeda (Eucalyptus globules) forest, and grassland, on soil quality and nutrient status in the lower Satluj basin of the Shiwalik foothills Himalaya, India. Samples were analyzed for assessment of physico-chemical properties at four soil depths, viz., 0–15, 15–30, 30–45, and 45–60 cm. A total of 120 soil samples were collected in both the seasons. Soil texture was found to be sandy loam and slightly alkaline in nature. The relative trend of soil organic carbon (SOC), macro- and micro-nutrient content for the five LUSs was forest > orchard > grassland > wheat–rice > sugarcane, in the pre- and post-monsoon seasons. SOC was highly correlated with macronutrients and micronutrients, whereas SOC was negatively correlated with soil pH (r = −0.818). The surface soil layer (0–15 cm) had a significantly higher content of SOC, and macro- and micro-nutrients compared to the sub-surface soil layers, due to the presence of more organic content in the soil surface layer. Tukey’s multiple comparison test was applied to assess significant difference (p < 0.05) among the five LUSs at four soil depths in both the seasons. Principle component analysis (PCA) identified that SOC and electrical conductivity (EC) were the most contributing soil indicators among the different land use systems, and that the post-monsoon season had better soil quality compared to the pre-monsoon season. These indicators helped in the assessment of soil health and fertility, and to monitor degraded agroecosystems for future soil conservation.

Simultaneous nitrification and denitrification in biofilters with real time aeration control

2001 ◽  
Vol 43 (1) ◽  
pp. 269-276 ◽  
Author(s):  
N. Puznava ◽  
M. Payraudeau ◽  
D. Thornberg
Keyword(s):  
Real Time ◽  
Nitrogen Removal ◽  
Simultaneous Nitrification And Denitrification ◽  
Biological Aerated Filter ◽  
Diffusion Effect ◽  
Different Depths ◽  
Nitrification And Denitrification ◽  
Aerated Filter ◽  
Denitrification Process ◽  
Aeration Control

The aim of this article is to present a new biological aerated filter (BAF) for nitrogen removal based on simultaneous nitrification and denitrification. Contrary to the systems which integrate both an aerated and a non-aerated zone to allow complete nitrogen removal in one compact or two different units (pre-denitrification and nitrification), this upflow BAF system is based on the principle of simultaneous nitrification and denitrification since the filter is completely aerated. The denitrification process is possible due to the diffusion effect which dominates biofilm processes. The real time aeration control allows us to maintain a low dissolved oxygen value (0.5 to 3 mg O2/l). In this case, the biofilm will not be fully (or less) penetrated with oxygen and denitrification will be carried out in a large part of the biofilm. Therefore, nitrification and denitrification is running simultaneously in different depths of the biofilm. By using 50% less air this BAF gave the same results (less than 20mg TN/l) on pilot plant as a classical nitrification and denitrification BAF (Toettrup et al., 1994). Less recirculation was necessary to achieve the same denitrification.

scholarly journals Empirical Characterization of Heavy Metals in Crude Oil Spill Sites in Emohua, Rivers State, Nigeria

2021 ◽  
Vol 2 (5) ◽  
pp. 24-28
Author(s):  
Nnamdi Michael Ahiamadu ◽  
Ify L. Nwaogazie ◽  
Yusuf O. L. Momoh
Keyword(s):  
Heavy Metals ◽  
Surface Water ◽  
Oil Spill ◽  
Environmental Protection Agency ◽  
Surface Soil ◽  
Soil Samples ◽  
Petroleum Resource ◽  
Significant Difference ◽  
Rivers State ◽  
Pb Concentration

The study assessed the concentration of heavy metals in three oil spill sites in Emohua local government area in Rivers State, Nigeria. Soil samples were collected at depth 0-30cm for surface soil samples and up to 10m for sub-surface soil samples depending on the depth of borehole. Groundwater samples were collected from drilled boreholes while the surface water samples were collected from fishponds or water bodies (rivers) close to the oil spill sites. The samples taken from the oil spill sites were analysed to determine the level of concentration of 10 Department of Petroleum Resource (DPR) specified heavy metals (Cd, Zn, Cu, Pb, Cr, Ba, Ni, Hg, As, and Co). BUCK Scientific Atomic Absorption Spectrophotometer (AAS) was used in detecting the concentration of the heavy metals. For the surface soil, Pb concentration in site A and B were significantly higher than what was obtained at site C, with a mean concentration of 219.70, 130.01 and 3.41mg/kg respectively for the three sites. The mean lead (Pb) concentration obtained in the surface soil was within DPR and United State Environmental Protection Agency (USEPA) acceptable limits. Barium also has significant concentration in both the surface soil and sub-surface soil. Kruskal Wallis test indicated significant difference in the Pb, Cd, Zn, Cu, Cr and Ba concentration in surface/topsoil among the three sites and also indicated significant difference in the concentrations of Pb, Cd, Cr, Ni, Ba and As in sub-surface soil among the sites. Little heavy metal concentration was found in both the groundwater and surface water. The study showed that even if some heavy metals were detected at the oil spill sites, they do not pose any serious health risk, as all the heavy metals in the four environmental media at the three sampling sites were below the national limit stipulated by the Department of Petroleum Resource (DPR), Nigeria.

scholarly journals Effects of delivering the same radiant exposures at 730, 1450, and 2920 mW/cm2 to two resin-based composites

2017 ◽  
Vol 11 (01) ◽  
pp. 022-028 ◽  
Author(s):  
Maan M. AlShaafi
Keyword(s):  
Fourier Transform ◽  
Degree Of Conversion ◽  
Attenuated Total Reflectance ◽  
Curing Time ◽  
Total Reflectance ◽  
Metal Rings ◽  
Significant Difference ◽  
Light Curing ◽  
Knoop Microhardness ◽  
Different Depths

ABSTRACT Objective: To evaluate the effects of curing two resin-based composites (RBC) with the same radiant exposures at 730, 1450, and 2920 mW/cm2. Materials and Methods: Two types of RBC, Filtek Supreme Ultra and Tetric-EvoCeram-Bulk Fill, were light-cured to deliver the same radiant exposures for 5, 10, or 20 s by means of a modified Valo light emitted diode light-curing unit with the light tip placed directly over each specimen. The RBC was expressed into metal rings that were 2.0 and 4.0 mm in thickness, directly on an attenuated total reflectance Fourier transform infrared plate heated to 33°C, and the degree of conversion (DC) of the RBC was recorded. The specimens were then removed and the Knoop microhardness (KHN) was tested at both the bottom and the top of each specimen. The KHN was tested again after 24 h and 7 days of storage in the dark at 37°C and 100% humidity. The DC and KHN results were analyzed with Fisher's protected least significant difference at α = 0.05. Results: The DC values for the specimens cured at the three different irradiance levels were similar. However, at different depths, there were differences in the DC values. In general, there were no clear differences among the samples cured in the three different groups, and the KHN was always greater 24 h and 7 days later (P < 0.05). Conclusions: Despite the curing time, and as long as the samples were cured with the same radiant exposures, there were no significant effects on the DC and KHN of both RBCs.

Studies on the Bionomics of the Case-bearing Clothes Moth, Tinea pellionella (L.)

1956 ◽  
Vol 47 (1) ◽  
pp. 167-182 ◽  
Author(s):  
P. S. Cheema
Keyword(s):  
Larval Development ◽  
Incubation Period ◽  
Wide Distribution ◽  
Effect Of Temperature ◽  
Continuous Darkness ◽  
Significant Difference ◽  
Temperature And Humidity ◽  
Important Pest ◽  
Orange G ◽  
Extent Of Damage

Tinea pellionella (L.), commonly known as the Case-bearing Clothes Moth or Fur Moth, is of world-wide distribution and is of considerable economic importance. It has been recorded on a variety of substances, particularly those of a keratinous nature. In India, it has been found as an important pest of woollen textiles. Its life-history and habits have been systematically investigated at different levels of temperature and humidity.The incubation period is 4 to 5, 5, 6 to 7 and 6 to 7 days at 21·5, 25, 30 and 32·5°C., respectively. Temperatures higher than 32·5°C. have been found lethal to eggs. Humidity has no effect on the incubation period. Percentage viability of eggs is greater at lower than at higher temperatures.Both temperature and humidity have been found to influence the larval development and the number of larval instars. Irrespective of temperature, higher humidities favour shorter larval development and the shortest larval period is at 25°C. and 90 per cent. R.H.Woollen materials impregnated with yeast are more suited for the larval development than those not so treated. Larvae do not exhibit colour preference. Woollen fabrics dyed with Cloth fast orange G 4 per cent, manufactured by “ Ciba ”, however, inhibit the growth of freshly hatched larvae.The behaviour of the larvae to direct sunlight has been studied. The rôle of (a) diffused light alternated with darkness, (b) darkness, (c) temperature and (d) humidity on the extent of damage caused by the larvae has been investigated. Under the conditions of the experiments, the amount of damage in continuous darkness was significantly greater than in alternating light and darkness, and that at 90 per cent. R.H. significantly greater than at 30 per cent., but there was no significant difference in the amount of damage at 27·5° and 32·5°C., respectively, and 90 per cent. R.H.The mode of pupation has been described. The pupal period has been studied and found.to occupy 18 ± 0·4, 10·3 ± 0·16 and 10·3 ± 0·33 days at 21·5, 25 and 30°C. and 90 per cent. R.H., respectively. Humidity has no effect on this period.The effect of temperature and humidity on (a) the preoviposition, oviposition and postoviposition periods and (b) number of eggs laid by a female has been studied. The life-span of the male and female, the relationship between the weight of the female at emergence and fecundity (which was highly significant) on the one hand and length of life (which was not significant) on the other has also been investigated. Sex ratio between females and males has been found to be 2·6:1. Three to four generations in a year have been recorded at 26 ± 8·0°C. and 82 ± 10 per cent. R.H. when the larvae are fed on woollen fabrics impregnated with yeast.

scholarly journals DETECTION AND TRANSMISSION OF RICE STUNT VIRUS ON CIHERANG AND SITU BAGENDIT VARIETIES

2019 ◽  
Vol 18 (2) ◽  
pp. 169
Author(s):  
Selvi Helina ◽  
Sri Sulandari ◽  
Sedyo Hartono ◽  
Andi Trisyono
Keyword(s):  
Plant Height ◽  
Incubation Period ◽  
Rice Production ◽  
Rice Plants ◽  
Inhibition Of Growth ◽  
Randomized Design ◽  
Significant Difference ◽  
Number Of Leaves ◽  
Completely Randomized Design ◽  
Rice Ragged Stunt Virus

Detection and Transmission of  rice stunt virus on Ciherang and Situ Bagendit Varieties. The explosion of brown planthoppers recently has caused reduction of rice production in Indonesia. Brown planthoppers do not only act as pest, but also transmit Rice grassy stunt virus (RGSV) and Rice ragged stunt virus (RRSV). Detection of the existence of the two viruses in rice plants and vector insects is important to be done to ensure that the virus is infected with the vector. The aim of this research is to detect the existence of virus in varieties of Ciherang and Situ Bagendit as a result of transmission in the laboratory and to find out the ability of brown planthoppers to transmit stunt virus to both of the varieties. This research was compiled using Completely Randomized Design (CRD) with 4 treatments, namely healthy rice plants of Ciherang and Situ Bagendit varieties, Ciherang and Situ Bagendit varieties which were infested by brown planthoppers each with 5 repetitions. The parameters observed were incubation period, symptoms, plant height, number of leaves and incidence of disease. The data on plant height, number of leaves and incidence of disease were analyzed using ANOVA and continued with the Least Significant Difference (LSD) test at the level of 5%. The results showed that Ciherang and Situ Bagendit varieties were only positively infected by Rice ragged stunt virus. The results of the rice transmission showed that Ciherang variety had a faster incubation period of 10 DAI while Situ Bagendit was 14 DAI, but the two varieties showed an inhibition of growth in plant height and number of leaves compared to healthy plants with each incidence of 51.3% and 46.3%.

302 VIABILITY OF BOVINE SPERMATOZOA INCUBATED WITH FOREIGN DNA

2006 ◽  
Vol 18 (2) ◽  
pp. 258
Author(s):  
W. B. Feitosa ◽  
M. P. Milazzoto ◽  
M. Rovegno ◽  
L. F. Martins ◽  
J. A. Visintin ◽  
...  
Keyword(s):  
Incubation Period ◽  
Molecular Probes ◽  
Control Group ◽  
Mitochondrial Activity ◽  
Sperm Viability ◽  
Exogenous Dna ◽  
Significant Difference ◽  
Class 1 ◽  
Bovine Spermatozoa ◽  
Over Time

Several studies have been performed over the years to promote the understanding and improvement of the sperm-mediated gene transfer technique. However, little is known about the effect of exogenous DNA in the sperm cells. The aim of this study was to evaluate the effect of the incubation period and exogenous DNA addition on mitochondrial activity and acrosomal status of bovine spermatozoa. Frozen-thawed semen was separated by Percoll gradient (45/90%) at 600g for 30 min, and the pellet was resuspended and washed by centrifugation in sperm-TALP at 200g for 5 min. The spermatozoa were resuspended in fertilization medium (without heparin) at a concentration of 5 × 106 spermatozoa/mL and incubated at 39°C, 5% CO2 in air with 500 ng pEYFP-Nuc/mL (Clontech, Mountain View, CA, USA) (DNA group) for 1 and 2 h or without DNA (control group) for 0, 1 and 2 h. JC-1 (Molecular Probes; Invitrogen Brasil, Ltd., Sao Paulo, Brazil) was used to determine mitochondrial potential and fluorsecein isothiogyanate (FITC-PSA; Sigma-Aldrich, Brazil) was used to assess acrosomal status. Two microliters of JC-1 (76.5 μM in DMSO) and 50 μL of FITC-PSA (100 μg/mL in DPBS) were added to 150 μL of IVF medium + 5 × 106 spermatozoa/mL; the mixture was incubated at 25°C for 10 min. DNA incorporation was evaluated by p-EYFP-Nuc PCR amplification. All treatments were repeated ten times and data were analyzed by ANOVA and Tukey test (P < 0.05). The results are described in Table 1. The sperm were classified as: Class 1 (intact acrosome and high mitochondria potential), Class 2 (intact acrosome and low mitochondria potential), Class 3 (reacted acrosome and high mitochondria potential) and Class 4 (reacted acrosome and low mitochondria potential). In both groups, the Class 1 sperm decreased over time, whereas an increase in number was verified for Class 2 sperm. There was no significant difference in numbers among the incubation periods in both groups for Class 3 sperm. However, there was an increase in Class 4 sperm number over time, indicating that the main effect of the incubation period was the loss of mitochondria potential. There was no effect of the exogenous DNA addition on sperm viability in relation to the control group, indicating that the exogenous DNA had no effect on mitochondrial activity and acrosomal status of bovine semen. Table 1. Effect of incubation period and exogenous DNA addition on sperm viability This work was supported by FAPESP 03/10234–7; 03/07456–8.

Nitrous oxide emission during nitrification and denitrification in a full-scale night soil treatment plant

1996 ◽  
Vol 34 (1-2) ◽  
pp. 277-284 ◽  
Author(s):  
Hiroki Itokawa ◽  
Keisuke Hanaki ◽  
Tomonori Matsuo
Keyword(s):  
Nitrous Oxide ◽  
Treatment Plant ◽  
Full Scale ◽  
Soil Treatment ◽  
Aeration Tank ◽  
N2o Emissions ◽  
N2o Production ◽  
Mixed Liquor ◽  
Significant Difference ◽  
Nitrification And Denitrification

Nitrous oxide (N2O) emissions from nitrification-denitrification processes in a full-scale night soil treatment plant were measured, and patterns and control of the N2O production were investigated. Estimated N2O emissions ranged from 4.4 to 1,190 gN/(m3 of influent), corresponding to a conversion ratio of influent nitrogen to N2O-N of 0.24-55%. N2O was produced in the intermittent aeration tank (IAT) where nitrification and denitrification were carried out alternately. The produced N2O was either stripped out to the off-gas or remained in the effluent in dissolved form. The former accounted for more than 99.5% of the total emissions. The latter flowed into the following anoxic tank, where 60-98% of N2O was reduced. A significant difference in the extent of N2O supersaturation in mixed liquor of IAT was observed between the cases of high and low N2O emissions. In IAT, N2O tended to be produced discretely either in aerobic or in anoxic phases. It seemed that the completeness of nitrification and denitrification in IAT, indicated from a mass balance between NH4-N and NO3-N and from NO2-N accumulation in mixed liquor of IAT, was one of the important factors affecting the N2O production. This completeness was decided by the time ratio of aerobic and anoxic phases. External addition of methanol to IAT seemed to reduce N2O emissions.

PHOSPHORUS FRACTIONS IN A SOIL SAMPLED AT DIFFERENT DEPTHS AND THE EFFECT OF LIME AND FERTILIZER ON OATS AND CLOVER IN A GREENHOUSE TEST

1960 ◽  
Vol 40 (1) ◽  
pp. 71-79
Author(s):  
H. A. Hamilton ◽  
J. R. Lessard
Keyword(s):  
Surface Soil ◽  
Crop Yields ◽  
Organic Phosphorus ◽  
Soil Phosphorus ◽  
Phosphate Fertilizer ◽  
Iron Phosphate ◽  
Soil Layers ◽  
Surface Samples ◽  
Different Depths ◽  
Total Soil Phosphorus

Soil samples were collected at four different depths from a virgin soil, and in a region where deep ploughing has been a common practice. Chemical analyses revealed that the sub-surface samples were more highly saturated with bases than were the surface samples. In the 0–6 inch layer the percentage contribution of calcium, aluminium and iron phosphate to total soil phosphorus was 41.1, 10.4 and 2.8 respectively; while, in the 18–24 inch layer the percentages were 88.4, 2.8 and 0.5 respectively. Organic phosphorus decreased with depth.In the greenhouse there were highly significant differences between oat yields on the various layers, the surface soil giving the highest yields. Clover crop yields tended to be better as depth of profile increased. Phosphorus increased oat yields and clover yields on all soil layers. As a result of over-liming in certain instances clover yields were depressed in the absence of applied phosphate fertilizer, whereas oat yields were unaffected.

Retrieving freeze/thaw-cycles using Sentinel 1 data in Eastern Nunavik (Québec, Canada)

2021 ◽  
Author(s):  
Yueli Chen ◽  
Lingxiao Wang ◽  
Monique Bernier ◽  
Ralf Ludwig
Keyword(s):  
Remote Sensing ◽  
Time Series ◽  
Surface Soil ◽  
Microwave Remote Sensing ◽  
Retrieval Algorithm ◽  
State Transitions ◽  
Freeze Thaw ◽  
High Quality Information ◽  
Different Depths ◽  
Spatio Temporal

&lt;p&gt;In the terrestrial cryosphere, freeze/thaw (FT) state transitions play an important and measurable role for climatic, hydrological, ecological, and biogeochemical processes in permafrost landscapes. Satellite active and passive microwave remote sensing has shown its principal capacity to provide effective monitoring of landscape FT dynamics. Sentinel-1 continues to deliver high-resolution microwave remote sensing than ever before and has therefore a large potential of usage for monitoring. In light of this, the capability and responses of its radar backscatter to landscape FT processes in different surface soil depths should be examined to provide a thorough grounding for a robust application of the F/T retrieval algorithm.&lt;/p&gt;&lt;p&gt;This study presents a seasonal threshold approach, which examines the time series progression of remote sensing measurements relative to signatures acquired during seasonal reference frozen and thawed states. It is developed to estimate the FT-state from the Sentinel 1 database and applied and evaluated for the region of Eastern Nunavik (Qu&amp;#233;bec, Canada). In this course, the FT state transitions derived from Sentinel 1 data are compared to temporally overlapping situ measurements of soil moisture from different depths within the top 20cm soil. This work allows to explore differences in the sensitivity of the Sentinel 1 at different surface soil depths in higher detail; this information is used to examine the penetration performance of the Sentinel 1 under different conditions of permafrost and permafrost-dominated landscapes.&lt;/p&gt;&lt;p&gt;This work is dedicated to providing more accurate data to capture the spatio-temporal heterogeneity of freeze/thaw transitions. As Sentinel-1 continues to deliver high-quality information, the provided threshold algorithm delivers an extended time series to analyze FT-states and improve our understanding of related processes in permafrost landscapes.&lt;/p&gt;

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