scholarly journals Denitrification as a component of Nitrogen Budget in a Tropical Paddy Field

2013 ◽  
Vol 9 (2) ◽  
pp. 159-165 ◽  
Keyword(s):  
Mass Balance ◽  
Direct Method ◽  
Balance Model ◽  
N Fixation ◽  
N Loss ◽  
Total N ◽  
Biological N Fixation ◽  
Weed Growth ◽  
Before And After ◽  
The Difference

The direct assessment of denitrification suffers from a number of problems. A mass balance model is simple and widely accepted to calculate nitrogen (N) loss as a denitrification component. The objective of study was to estimate the potential N loss a denitrification from a tropical paddy in the central region of Thailand. N inputs to and outputs from field were measured by direct method. Inputs of N to the site were commercial fertilizer, precipitation, irrigation water, seeds and pre-cultivation soils. Outputs of nitrogen from the site were leaching to groundwater, harvested crops, loads in surface runoff, post harvest soils and loss from the field as denitrification. Biological N fixation, groundwater contribution, ammonium volatilization and contribution to weed growth were ignored. Based on the three month observation, the total amount of N load in irrigation, precipitation, fertilizer, drainage, percolation and plant uptake were 9.22, 10.85, 100, 4.65, 18.20 and 80.57 kg ha-1 respectively. The difference of total N in the soil before and after cultivation was not significant and taken as constant value. Sum of N loss calculated as denitrification component from the nitrogen mass balance model was 16.7 kg ha-1 and rate of loss was 0.19 kg ha-1 d-1. It means that the contribution of applied N fertilizer to the atmosphere was 13.6% of total N input; indicating one of the major source pollutants.

scholarly journals Comparison of direct and geodetic mass balances on a multi-annual time scale

2010 ◽  
Vol 4 (3) ◽  
pp. 1151-1194
Author(s):  
A. Fischer
Keyword(s):  
Mass Balance ◽  
Direct Method ◽  
Mean Difference ◽  
Published Data ◽  
Glacier Mass Balance ◽  
Mass Balances ◽  
Direct Data ◽  
The Mean ◽  
The Difference ◽  
Geodetic Mass Balance

Abstract. Glacier mass balance is measured with the direct or the geodetic method. In this study, the geodetic mass balances of six Austrian glaciers in 19 periods between 1953 and 2006 are compared to the direct mass balances in the same periods. The mean annual geodetic mass balance for all periods is −0.5 m w.e./year. The mean difference between the geodetic and the direct data is −0.7 m w.e., the minimum −7.3 m w.e. and the maximum 5.6 m w.e. The accuracy of geodetic mass balance resulting from the accuracy of the DEMs ranges from 2 m w.e. for photogrammetric data to 0.002 m w.e. for LIDAR data. Basal melt, seasonal snow cover and density changes of the surface layer contribute up to 0.7 m w.e. for the period of 10 years to the difference to the direct method. The characteristics of published data of Griesgletscher, Gulkana Glacier, Lemon Creek glacier, South Cascade, Storbreen, Storglaciären, and Zongo Glacier is similar to these Austrian glaciers. For 26 analyzed periods with an average length of 18 years the mean difference between the geodetic and the direct data is −0.4 m w.e., the minimum −7.2 m w.e. and the maximum 3.6 m w.e. Longer periods between the acquisition of the DEMs do not necessarily result in a higher accuracy of the geodetic mass balance. Specific glaciers show specific trends of the difference between the direct and the geodetic data according to their type and state. In conclusion, geodetic and direct mass balance data are complementary, but differ systematically.

scholarly journals Residual effect of clover-rich leys on soil nitrogen and successive grain crops

2008 ◽  
Vol 17 (1) ◽  
pp. 73 ◽  
Author(s):  
A. NYKÄNEN ◽  
A. GRANSTEDT ◽  
L. JAUHIAINEN
Keyword(s):  
Field Experiments ◽  
Clayey Soil ◽  
N Uptake ◽  
Residual Effect ◽  
Red Clover ◽  
N Leaching ◽  
N Fixation ◽  
Mineral N ◽  
Total N ◽  
Biological N Fixation

Legume-based leys form the basis for crop rotations in organic farming as they fix nitrogen (N) from the atmosphere for the succeeding crops. The age, yield, C:N, biological N fixation (BNF) and total N of red clover-grass leys were studied for their influence on yields, N uptake and N use efficiency (NUE) of the two sequential cereal crops planted after the leys. Mineral N in deeper soil (30-90 cm) was measured to determine N leaching risk. Altogether, four field experiments were carried out in 1994-1998 at two sites. The age of the ley had no significant effect on the yields and N uptake of the two subsequent cereals. Surprisingly, the residual effect of the leys was negligible, at 0–20 kg N ha-1yr-1. On the other hand, the yield and C:N of previous red clover-grass leys, as well as BNF-N and total-N incorporated into the soil influenced subsequent cereals. NUEs of cereals after ley incorporation were rather high, varying from 30% to 80%. This might indicate that other factors, such as competition from weeds, prevented maximal growth of cereals. The mineral N content deeper in the soil was mostly below 10 kg ha-1 in the sandy soil of Juva, but was 5-25 kg ha-1 in clayey soil of Mietoinen.;

scholarly journals Recent variations of calving glaciers in Patagonia, South America, revealed by ground surveys, satellite-data analyses and numerical experiments

1995 ◽  
Vol 21 ◽  
pp. 297-303 ◽  
Author(s):  
Renji Naruse ◽  
Masamu Aniya ◽  
Pedro Skvarca ◽  
Gino Gasassa
Keyword(s):  
South America ◽  
Mass Balance ◽  
Numerical Experiments ◽  
Satellite Images ◽  
Balance Model ◽  
Equilibrium Line Altitude ◽  
Simple Mass ◽  
Surface Profiles ◽  
The Difference ◽  
Altitudinal Distributions

Large retreats were revealed for most glaciers in Patagonia, South America, by analyzing satellite images and air photographs. For example, Glaciar O’Higgins retreated 13 km during 41 years from 1945 to 1986 and Glaciar Upsala retreated about 3 km between 1968 and 1990. During the 41 years former period, however, the southern tongue of Glaciar Pio XI advanced by up to 8.5 km and Glaciar Moreno remained almost in a steady state. Considerable ice-thinning rates, from 3.0 to 11 ma−1, were measured by surveying surface profiles in the ablation areas of Tyndall and Upsala glaciers, respectively, during the period from 1985 (or 1990) to 1993. The ice thickness of Glaciar Moreno, however, has changed very little. Numerical experiments using a simple mass-balance model show that a 100 m rise in the equilibrium-line altitude due to climatic change would result in about a 200–350 m rise in the frontal altitude at Glaciar Upsala corresponding to a retreat of 5–8 km, while it would cause only about a 70–100 m rise at Glaciar Moreno. The large difference between these two neighbouring glaciers results from the difference in contributions of the calving amount to the total mass balance, as well as the difference in the altitudinal distributions of drainage areas.

scholarly journals Recent variations of calving glaciers in Patagonia, South America, revealed by ground surveys, satellite-data analyses and numerical experiments

1995 ◽  
Vol 21 ◽  
pp. 297-303 ◽  
Author(s):  
Renji Naruse ◽  
Masamu Aniya ◽  
Pedro Skvarca ◽  
Gino Gasassa
Keyword(s):  
South America ◽  
Mass Balance ◽  
Numerical Experiments ◽  
Satellite Images ◽  
Balance Model ◽  
Equilibrium Line Altitude ◽  
Simple Mass ◽  
Surface Profiles ◽  
The Difference ◽  
Altitudinal Distributions

Large retreats were revealed for most glaciers in Patagonia, South America, by analyzing satellite images and air photographs. For example, Glaciar O’Higgins retreated 13 km during 41 years from 1945 to 1986 and Glaciar Upsala retreated about 3 km between 1968 and 1990. During the 41 years former period, however, the southern tongue of Glaciar Pio XI advanced by up to 8.5 km and Glaciar Moreno remained almost in a steady state. Considerable ice-thinning rates, from 3.0 to 11 ma−1, were measured by surveying surface profiles in the ablation areas of Tyndall and Upsala glaciers, respectively, during the period from 1985 (or 1990) to 1993. The ice thickness of Glaciar Moreno, however, has changed very little.Numerical experiments using a simple mass-balance model show that a 100 m rise in the equilibrium-line altitude due to climatic change would result in about a 200–350 m rise in the frontal altitude at Glaciar Upsala corresponding to a retreat of 5–8 km, while it would cause only about a 70–100 m rise at Glaciar Moreno. The large difference between these two neighbouring glaciers results from the difference in contributions of the calving amount to the total mass balance, as well as the difference in the altitudinal distributions of drainage areas.

Nodulation dynamics and nodule activity in leguminous tree species of a Mexican tropical dry forest

2008 ◽  
Vol 24 (1) ◽  
pp. 107-110 ◽  
Author(s):  
Teresa González-Ruiz ◽  
Víctor J. Jaramillo ◽  
Juan José Peña Cabriales ◽  
Arturo Flores
Keyword(s):  
Tropical Dry Forest ◽  
Dry Forest ◽  
Nodule Formation ◽  
N Fixation ◽  
Legume Species ◽  
Leguminous Tree ◽  
Total N ◽  
Biological N Fixation ◽  
Important Pathway ◽  
Micro Organisms

Biological N fixation by symbiotic micro-organisms plays a key role in making atmospheric N largely available to other organisms and nodule formation by rhizobia in roots of many legume species represents a very important pathway (Postgate 1998). Estimates of the contribution of symbiotic fixation to total N content in soils range from 44 to 200 Tg y−1(Bøckman 1997).

scholarly journals Surface mass balance, thinning and iceberg production, Columbia Glacier, Alaska, 1948–2007

2011 ◽  
Vol 57 (203) ◽  
pp. 431-440 ◽  
Author(s):  
L.A. Rasmussen ◽  
H. Conway ◽  
R.M. Krimmel ◽  
R. Hock
Keyword(s):  
Mass Balance ◽  
Meteorological Data ◽  
Balance Model ◽  
Surface Mass Balance ◽  
Mass Balance Model ◽  
Surface Mass ◽  
Surface Ablation ◽  
Positive Balance ◽  
Remarkable Result ◽  
The Difference

AbstractA mass-balance model using upper-air meteorological data for input was calibrated with surface mass balance measured mainly during 1977–78 at 67 sites on Columbia Glacier, Alaska, between 135 and 2645 m a.s.l. Root-mean-square error, model vs measured, is 1.0 m w.e. a−1, with r2 = 0.88. A remarkable result of the analysis was that both precipitation and the factor in the positive degree-day model used to estimate surface ablation were constant with altitude. The model was applied to reconstruct glacier-wide components of surface mass balance over 1948–2007. Surface ablation, 4 km3 ice eq. a−1 (ice equivalent), has changed little throughout the period. From 1948 until about 1981, when drastic retreat began, the surface mass balance was positive but changes in glacier geometry were small, so the positive balance was offset by calving, ∼0.9 km3 ice eq. a−1 . During retreat, volume loss of the glacier accounted for 92% of the iceberg production. Calving increased to ∼4.3 km3 ice eq. a−1 from 1982 to 1995, and after that until 2007 to ∼8.0 km3 ice eq. a−1, which was about twice the loss by surface ablation, whereas prior to retreat it was only about a quarter as much. Calving is calculated as the difference between glacier-wide surface mass balance and geodetically determined volume change.

scholarly journals Quantification of nitrogen balance components in a commercial broiler barn 

2013 ◽  
Vol 58 (No. 12) ◽  
pp. 566-577 ◽  
Author(s):  
K. von Bobrutzki ◽  
S. Ammon ◽  
W. Berg ◽  
M. Fiedler
Keyword(s):  
Mass Balance ◽  
Management Practices ◽  
N Accumulation ◽  
Total N ◽  
N Input ◽  
Commercial Broiler ◽  
Use Efficiency ◽  
The Difference ◽  
Inputs And Outputs

Characterizing the respective nitrogen (N) use efficiency requires understanding the N flow of inputs and outputs from a commercial broiler barn. In this study, an N mass balance was performed for one entire growing cycle. The objectives were to quantify, sample, and analyze all N components entering and leaving the barn. The N from feed, chickens, and bedding material was considered as inputs, the outputs included the N accretion in mature broilers, the total N emissions (N<sub>TNE</sub>), the N accumulation in litter, and the N of mortality. Of particular relevance was the determination of an appropriate method to mirror the heterogenic texture of the litter. Litter samples were collected weekly according to a defined procedure. The major N input was feed N, accounting for 99% of the total N input. After the 36-day growing cycle, the N outputs were portioned as follows: 59% (1741.3 kg N) in mature broilers, 37% (1121.3 kg N) accumulated in litter, and 4% in NTNE (114.3 kg N). The N accumulations in broiler tissue and litter agree well with other studies. The measured emissions were consistently lower compared to other references, due to the fact that these references were mainly based on studies where broilers were raised on built-up litter. In contrast to in situ quantified N emissions in this study, other published values were assumed to be the difference of N between inputs and outputs. This study illustrates that extensive sampling of litter is a prerequisite for calculating litter masses. The accurate specification of the litter texture proved to be crucial within the mass balance approach. With this information, the feasible improvements within management practices can be identified.

scholarly journals Mass Balance Reconciliation for Bilinear Systems: A Case Study of a Raw Mill Separator in a Typical Moroccan Cement Plant

2016 ◽  
Vol 6 (3) ◽  
pp. 1006-1009 ◽  
Author(s):  
S. Fellaou ◽  
T. Bounahmidi
Keyword(s):  
Mass Balance ◽  
Stream Flow ◽  
Data Reconciliation ◽  
Balance Model ◽  
Mass Balance Model ◽  
Mass Balances ◽  
Flow Rates ◽  
Simultaneous Procedures ◽  
The Difference

Stream flow rates and their several compositions are measured in a typical cement raw mill separator. In order to simultaneously reconcile flow and composition measurements in this circuit, the component mass balances was included as constraints which contain the products of flow rate and composition variables in the data reconciliation problem. In this paper, the effectiveness of simultaneous procedures for bilinear data reconciliation is established, the numerical problem constraints were coded in MATLAB and a mass balance model is built. Moreover, based on the difference between the measured and reconciled data it was found that it performs optimally.

scholarly journals Inoculation of sugarcane with diazotrophic bacteria

2014 ◽  
Vol 38 (2) ◽  
pp. 407-414 ◽  
Author(s):  
Nivaldo Schultz ◽  
Jeferson Alves da Silva ◽  
Jailson Silva Sousa ◽  
Rafael Cassador Monteiro ◽  
Renan Pedula Oliveira ◽  
...  
Keyword(s):  
Dry Matter ◽  
Production Efficiency ◽  
Growth Promotion ◽  
N Fixation ◽  
Dry Matter Accumulation ◽  
Diazotrophic Bacteria ◽  
Biological Fixation ◽  
Total N ◽  
N Nutrition ◽  
Biological N Fixation

The sugarcane industry, a strategic crop in Brazil, requires technological improvements in production efficiency to increase the crop energy balance. Among the various currently studied alternatives, inoculation with diazotrophic bacteria proved to be a technology with great potential. In this context, the efficiency of a mixture of bacterial inoculant was evaluated with regard to the agronomic performance and N nutrition of sugarcane. The experiment was carried out on an experimental field of Embrapa Agrobiologia, in Seropédica, Rio de Janeiro, using a randomized block, 2 × 3 factorial design (two varieties and three treatments) with four replications, totaling 24 plots. The varieties RB867515 and RB72454 were tested in treatments consisting of: inoculation with diazotrophic bacteria, N-fertilized control with 120 kg ha-1 N and absolute control (no inoculation and no N fertilizer). The inoculum was composed of five strains of five diazotrophic species. The yield, dry matter accumulation, total N in the shoot dry matter and the contribution of N by biological fixation were evaluated, using the natural 15N abundance in non-inoculated sugarcane as reference. The bacterial inoculant increased the stalk yield of variety RB72454 similarly to fertilization with 120 kg ha-1 N in the harvests of plant-cane and first ratoon crops, however the contribution of biological N fixation was unchanged by inoculation, indicating that the benefits of the inoculant in sugarcane may have resulted from plant growth promotion.

scholarly journals Clinical Effectiveness of Ertapenem Versus Piperacillin/Tazobactam in Patients With Mild to Moderate Intraabdominal Infections: A Systematic Review and Metaanalysis of Randomized Controlled Trials

2020 ◽  
Vol 7 (4) ◽  
pp. 129-134
Author(s):  
Mehran Pezeshki ◽  
Fatemeh Soleymani ◽  
Meysam Seyedifar
Keyword(s):  
Randomized Clinical Trials ◽  
Direct Method ◽  
Clinical Effectiveness ◽  
Adult Patients ◽  
Significant Difference ◽  
Before And After ◽  
The Difference ◽  
Mean Differences ◽  
Abdominal Infections ◽  
Intraabdominal Infections

Purpose: This study aimed to search for randomized clinical trials evaluating the clinical effectiveness of ertapenem compared to piperacillin/tazob actam in adult patients with mild to moderate intra-abdominal infections. Design: A literature review was performed in PubMed, Scopus, Google Scholar, and Cochrane databases in order to find articles published up to April 2019. Then, the pairwise method was used to compare the difference between the mean score of the clinical effectiveness of these two interventions before and after the intervention by the means of a non-direct method (the comparison of drugs with each other). Results: The analysis of 4 studies involving 767 patients in the ertapenem group and 728 patients in the piperacillin/tazobactam group showed that ertapenem can be 3% more effective than piperacillin/tazobactam (Weighted mean differences = 3.02, confidence interval (0.79-6.84) although the difference was insignificant (I-squared = 0.0%, P=0.98) Conclusions: In general, the findings demonstrated that there is no significant difference in the clinical effectiveness of ertapenem in comparison with piperacillin/tazobactam in adult patients with mild to moderate intra-abdominal infections.

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