scholarly journals Effect of thinning on the amount of mineral nitrogen

2018 ◽  
Vol 64 (No. 7) ◽  
pp. 289-295
Author(s):  
Holík Ladislav ◽  
Rosíková Jana ◽  
Vranová Valerie
Keyword(s):  
Nitrogen Content ◽  
Soil Nitrogen ◽  
Nitrate Nitrogen ◽  
Ammonium Nitrogen ◽  
The Other ◽  
Small Decrease ◽  
The Impact ◽  
The Given ◽  
Soil Nitrogen Cycle ◽  
Insight Into

The soil nitrogen cycle and the dynamics of its transformation are closely related to the functioning of the forest ecosystem. This cycle, and the availability of nitrogen as a necessary nutrient in the soil, can be influenced by the process of thinning. The aim of this study is to describe the impact of silvicultural measures on the content of ammonium and nitrate nitrogen in forest soil. Attention is paid to the organic (spruce treatments) and organomineral horizon (beech treatments) in which the transformation of soil nitrogen is most pronounced. Spruce treatments at the Rájec-Němčice area and beech stands at the Březina area, both in the region of Drahanská vrchovina (Czech Republic), were selected for the experiments. Two variants of thinning thinning from below and thinning from above, were performed in the spruce treatments, and thinning from above was performed in the beech treatments. Control variants with no silvicultural measures were defined in both treatments. The amount of ammonium nitrogen in the spruce treatments with thinning from above was in most cases higher than in the other variants. On the contrary, in variant with thinning from below, the ammonium nitrogen content decreased. In terms of the nitrate nitrogen content, the values were generally higher for variants with silvicultural measures than for the control variants. In the beech treatments, the amount of ammonium nitrogen increased and, on the contrary, there was a small decrease in the amount of nitrate nitrogen due to the effect of thinning from above. The differences between thinning from above and the control variants in the beech treatments were less noticeable than in the spruce treatments. Overall, however, it can be said that the nitrogen content available to the vegetation increased. The results of the given experiment provide insight into the trends of nitrogen mineralization intensity in stands in which silvicultural measures are performed.

scholarly journals Impact of COVID-19 Variants on the Second Wave in India and Subsequent Discretion of Possibilities of the Third Wave

2021 ◽  
pp. 115-126
Author(s):  
Sudarshan Ramaswamy ◽  
Meera Dhuria ◽  
Sumedha M. Joshi ◽  
Deepa H Velankar
Keyword(s):  
Herd Immunity ◽  
Sir Model ◽  
The Other ◽  
Third Wave ◽  
Focal Points ◽  
Current Analysis ◽  
The Third ◽  
The Impact ◽  
Second Wave ◽  
Insight Into

Introduction: Epidemiological comprehension of the COVID-19 situation in India can be of great help in early prediction of any such indications in other countries and possibilities of the third wave in India as well. It is essential to understand the impact of variant strains in the perspective of the rise in daily cases during the second wave – Whether the rise in cases witnessed is due to the reinfections or the surge is dominated by emergence of mutants/variants and reasons for the same. Overall objective of this study is to predict early epidemiological indicators which can potentially lead to COVID-19 third wave in India. Methodology: We analyzed both the first and second waves of COVID-19 in India and using the data of India’s SARS-CoV-2 genomic sequencing, we segregated the impact of the Older Variant (OV) and the other major variants (VOI / VOC).  Applying Kermack–McKendrick SIR model to the segregated data progression of the epidemic in India was plotted in the form of proportion of people infected. An equation to explain herd immunity thresholds was generated and further analyzed to predict the possibilities of the third wave. Results: Considerable difference in ate of progression of the first and second wave was seen. The study also ascertains that the rate of infection spread is higher in Delta variant and is expected to have a higher threshold (>2 times) for herd immunity as compared to the OV. Conclusion: Likelihood of the occurrence of the third wave seems unlikely based on the current analysis of the situation, however the possibilities cannot be ruled out. Understanding the epidemiological details of the first and second wave helped in understanding the focal points responsible for the surge in cases during the second wave and has given further insight into the future.

scholarly journals Observations on the mobilization of peat nitrogen in incubation experiments

1959 ◽  
Vol 31 (1) ◽  
pp. 268-281
Author(s):  
Jaakko Kivekäs ◽  
Erkki Kivinen
Keyword(s):  
Nitrate Nitrogen ◽  
Ammonium Nitrogen ◽  
The Other ◽  
Incubation Experiments ◽  
Different Types ◽  
Working Out ◽  
Original Amount

60 peat samples from northern Finland representing different types of peat were incubated in a laboratory at a temperature of 17—18° C. The ammonium nitrogen, the nitrate nitrogen and the pH in the samples were determined after one month of incubation as well as after three months of incubation. The results were compared to results from determinations made before incubation. An attempt was made to elucidate the factors that influence the mobilization of nitrogen. On the basis of the above results it is evident that the differences between the various peat types as mobilizers of nitrogen are under these circumstances not very distinct, nor do these differences seem to be dependent on the types of peat. The following facts can, however, be established: In the amounts of ammonium nitrogen an increase takes place in most groups of samples during the first month. This increase is fairly big in the Sphagnum-dominated peats. The increase in ammonium nitrogen continues in the unlimed samples in most peat groups during all three months of incubation. After three months of incubation the amount of ammonium nitrogen in the limed samples is smaller than in the unlimed samples, although it is usually bigger than in the original samples. After the first month of incubation the amounts of nitrate nitrogen in all types of peat have decreased compared to the amounts in the original samples. In the limed samples the decrease is not as great as in the unlimed ones. After three months of incubation the amount of nitrate nitrogen has considerably increased as compared to the amount after one month of incubation. In the limed samples it might to some extent exceed the original amount of nitrate nitrogen, however, this is seldom the case in the unlimed samples. If the results are calculated on the basis of weight unit, it can be stated that the ability to mobilize nitrogen is greater in the Sphagnum peats than in the other peat groups. Working out the results in kg per ha it will be noted that somewhat more nitrogen is mobilized in the Carex-dominated than in the Sphagnum-dominated peats. The results obtained by experiments in the laboratory are not directly applicable to conditions in the field.

scholarly journals Impact of Turbulence Models on the Air Flow in a Confined Rectangular Space

2020 ◽  
pp. 46-53
Author(s):  
Jakub Mularski ◽  
Amit Arora ◽  
Muhammad Azam Saeed ◽  
Łukasz Niedźwiecki ◽  
Samrand Saeidi
Keyword(s):  
Experimental Data ◽  
Air Flow ◽  
Turbulence Models ◽  
The Other ◽  
Experimental Measurements ◽  
Wall Region ◽  
Sst Model ◽  
Computational Fluid Dynamics Cfd ◽  
The Impact ◽  
The Given

The paper regards the impact of four different turbulence models on the air flow pattern in a confined rectangular space. The following approaches are analyzed. The Baseline (BSL) Reynolds model, the Speziale-Sarkar-Gatzki (SSG) Reynolds model, the Menter's shear-stress transport (SST) model and the basic k-ε model. Computational fluid dynamics (CFD) results are compared with the experimental measurements in four different planes. The Reynolds number for the given conditions is equal to 5000. The k-ε model yielded the most accurate results with regard to the experimental data but its reliability decreased near the wall region. With respect to the other models, it was also found that the k-ε approach generated the least circulating flow.

The effects of ammonium and nitrate nitrogen on the growth of perennial rye grass

1936 ◽  
Vol 26 (2) ◽  
pp. 249-257 ◽  
Author(s):  
A. H. Lewis
Keyword(s):  
Nitrogen Content ◽  
Nitrate Nitrogen ◽  
Ammonium Nitrogen ◽  
Early Stages ◽  
Rye Grass

The results show clearly a more rapid and greater uptake of ammonium than of nitrate nitrogen by perennial rye grass grown in a sand-bentonite medium of pH 7·61. The extent to which the extra uptake with added ammonia was reflected in increased yields was dependent upon the age of the grass.Except in the very early stages the percentage nitrogen content of the herbage was higher where nitrate nitrogen was applied than where ammonium nitrogen was applied. This indicates that any nitrate absorbed by the plant was less, efficient in increasing yields than was ammonium nitrogen.The percentage P205 content of the grass was higher where the nitrogen was applied in the ammoniacal form than where it was applied as nitrate, and it appears that this greater P205 uptake with ammonium nitrogen resulted in increased growth.

Study on the Effects of Nitrogen Pollution to the Soil and Groundwater

2013 ◽  
Vol 437 ◽  
pp. 1019-1022 ◽  
Author(s):  
Xiao Hui Lu ◽  
Yang Wang
Keyword(s):  
Nitrogen Content ◽  
Nitrate Nitrogen ◽  
Flow Direction ◽  
Ammonium Nitrogen ◽  
Nitrogen Pollution ◽  
Monitoring Point ◽  
River Bank ◽  
The North ◽  
Geological Conditions ◽  
Nitrite Nitrate

Xuzhou city lies on the north of Jiangsu province, which geological conditions are complex, water resources are deficient and environment is vulnerable. At present, water pollution in Kui river area is very serious; Kui River nitrogen pollution had affected Coastal soil and chemical environment of groundwater. The monitoring sections are elected in the seriously polluted river, and downstream at the banks of river decorates with six monitoring sections. Each section from the river bank of 50m, 100m, 200m, 500m, 1000m, 1500m is arranged of monitoring points respectively, and each monitoring point is monitored for sampling test at different depths. The monitoring results of surface water showed that the content of ammonia-nitrite-nitrate was a decreasing trend along the flow direction. The nitrate nitrogen content would decrease further in December while the ammonium nitrogen content was on the rise, showing that the supplement of nitrogen pollution resources was still insufficient when the denitrification was stronger. The content of ammonium and nitrate nitrogen in soil was higher, and had some regular change features with the change of depth.

scholarly journals Observations on the effect of organic materila upon aggregation and nitrate-nitrogen content of soil

1952 ◽  
Vol 24 (3) ◽  
pp. 127-134
Author(s):  
Armi Kaila ◽  
Pertti Kivinen
Keyword(s):  
Nitrogen Content ◽  
Soil Nitrogen ◽  
Nitrate Nitrogen ◽  
Soil Samples ◽  
Mineral Nitrogen ◽  
Aggregation State ◽  
Water Stable Aggregates ◽  
Mineral Soils ◽  
Simultaneous Immobilization ◽  
Properties Of Soil

In the experiments reported above the effect of organic material upon the aggregation of soil particles and the simultaneous immobilization of mineral nitrogen by microorganisms were studied. The relative amount of water-stable aggregates larger than 0.5 mm in diameter was considered to indicate the aggregation state of the soil samples. Probably, somewhat different results were obtained if the crumb formation had been determined by some other method, but it is not sure that these would have been more reliable. Since the incubation of soil samples were performed under aerobic conditions, and all the samples were mineral soils, it seemed justifiable to take the nitrate-nitrogen content of the soil samples to characterize the amount of mineral nitrogen in them. On the basis of the results the general conclusion may be drawn that the more favourable the conditions are for the development of an active and large microflora in the soil, the more intensively the crumb formation and the immobilization of nitrogen takes place, but also the destruction of aggregates begins the more rapidlv. This appeared to be true with regard to the indigenous fertility of soil as well as to the fertilization. Liming, however, did not improve the conditions in these experiment, probably due to the rather slight acidity of the soil samples used. Under otherwise similar conditions the larger amount of straw produced larger amount of aggregates, but the differences in the nitrate-nitrogen content of soil in the presence of various amounts of straw were neglibigle. Generally, the degree of immobilization of soil nitrogen seemed largely to depend on the properties of soil and on other environmental conditions, and nitrogen applications, theoretically enough for the needs of microorganisms that decomposed the straw, could not always prevent an intensive absorption of soil nitrogen. The crumb formation appeared to need mere energy-yielding material than the immobilization of nitrogen, or the destruction of crumbs occurred more rapidly than the nitrification of microbiologically bound nitrogen.

Influence of growing various crops in five different fixed rotations on the changes in nitrate and total nitrogen content of soils

1985 ◽  
Vol 104 (3) ◽  
pp. 609-613 ◽  
Author(s):  
K. N. Sharma ◽  
A. L. Bhandari ◽  
M. L. Kapur ◽  
D. S. Rana
Keyword(s):  
Nitrogen Content ◽  
Total Nitrogen ◽  
Soil Nitrogen ◽  
Nitrate Nitrogen ◽  
Balance Sheet ◽  
Total Nitrogen Content ◽  
Soil N ◽  
Total N ◽  
Soil Layers ◽  
Total Soil N

SummaryThe results on the influence of various crops in five different fixed rotations on the ohanges in nitrate and total N content of soils are reported. Groundnut contributed largely to the accumulation of nitrate nitrogen in the soil profile (to a depth of 120 cm). Bajra fodder exhausted the soil nitrogen reserve to a great extent. Wheat and maize, in a rotation, reduced nitrate leaching to deeper soil layers. Summer moong also left a large amount of unabsorbed nitrate in the profile. Total nitrogen content of the soil decreased after the harvest of cereals. Maximum depletion occurred after the harvest of bajra crop. Potato (a crop which received a heavy dressing of N fertilizer) and legumes contributed to the soil N reserve. A balance sheet of N indicated net gains of total soil N in four of the five cropping sequences. A net loss of 75 kg N/ha was observed in bajra fodder-potato-wheat rotation.

Video-Enhanced Self-Administered Computer Interviews

2012 ◽  
pp. 99-119
Author(s):  
Joachim Gerich
Keyword(s):  
Data Collection ◽  
Data Quality ◽  
Preliminary Evidence ◽  
The Other ◽  
Video Sequences ◽  
Scientific Interest ◽  
The One ◽  
The Impact ◽  
Insight Into ◽  
Logical Extension

In video-enhanced computer interviews, questions are presented by virtual interviewers by means of pre-recorded video sequences. To date, two strands of scientific interest in video-enhanced data collection are identifiable. On the one hand, video-enhanced data collection is employed for interviewing respondents with special needs (especially deaf respondents) and young respondents. On the other hand, research is focused on the impact on data quality. Following previous results on enhanced data quality with audio-enhanced computer interviews, video-enhanced surveys are seen as a logical extension. In this chapter, previous research on both strands of applications of video-enhanced computer interviews is summarized to gain insight into preliminary evidence about the impact of these methods.

scholarly journals A Study on Managers' Creation of Budgetary Slack in Emerging Economies: The Case of Vietnam

2017 ◽  
Vol 2 (2) ◽  
pp. 15-28
Author(s):  
Quang-Huy Ngo ◽  
Thi-Nam-Ninh Doan ◽  
Thanh-Nha Huynh
Keyword(s):  
Information Asymmetry ◽  
Emerging Economies ◽  
The Other ◽  
Budgetary Slack ◽  
Future Studies ◽  
Developed Economies ◽  
Budgetary Participation ◽  
The Creation ◽  
The Impact ◽  
Insight Into

Although the budgeting literature well documents managers' creation of budgetary slack in developed economies, lack of attention has been paid to this behaviour in emerging economies. It is doubtful that some unique characteristics, only existing in emerging economies, cause this behaviour to be different than the budgeting literature predicts. Since there is no study examining managers' creation of budgetary slack in emerging economies, such as Vietnam, to get insight into whether or not these characteristics cause the differences, the aim of this study is to replicate prior budgeting studies by using Vietnamese samples. Particularly, we investigated the impact of budgetary participation, budget emphasis, information asymmetry, and the interactions between these variables on managers' creation of budgetary slack. Data obtained from the questionnaire sent to 99 Vietnamese managers shows that the last two variables and the interaction between them induce managers' creation of budgetary slack. However, the results also indicate that the first variable and the interaction between this variable and the other two variables respectively have no impact on managers' creation of budgetary slack. These results provide some insight into the creation of budgetary slack of Vietnamese managers for future studies to extend the line of research.

scholarly journals Motivačné aspekty rozhodovania pre vysokoškolské štúdium

2020 ◽  
pp. 16-24
Author(s):  
Barbora Blašková
Keyword(s):  
Higher Education ◽  
Theoretical Level ◽  
Scientific Methods ◽  
The Third ◽  
Life Long Learning ◽  
The Impact ◽  
The Given ◽  
Theoretical Foundations ◽  
Insight Into

This paper addresses the issue of motivation on the theoretical level. Nowadays, the emphasis is put on life-long learning and the individual’s ability to continuously develop their skills. By investigating the theoretical foundations of motivation, I emphasize its importance in the academy environment. Motivation can be considered as a relevant part of studying, academic performance or success. In the first chapter dealing with an insight into the researched issue, I focus on the views of individual authors on motivation. In the second chapter, I point out the impact of motivation on personality. Last but not least, in the third chapter, I characterize the specific motivational aspects for higher education. The paper aimed to show how motivation is important in education, and overall it forms an essential part of our actions or decisions, which also represents the result of the given article. Different scientific methods were used during the paper elaboration, such as description, synthesis, analysis or comparison.

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