scholarly journals Aerodynamic gradient measurements of the NH<sub>3</sub>-HNO<sub>3</sub>-NH<sub>4</sub>NO<sub>3</sub> triad using a wet chemical instrument: an analysis of precision requirements and flux errors

2010 ◽  
Vol 3 (1) ◽  
pp. 187-208 ◽  
Author(s):  
V. Wolff ◽  
I. Trebs ◽  
C. Ammann ◽  
F. X. Meixner
Keyword(s):  
Nitric Acid ◽  
Ammonium Nitrate ◽  
Field Experiments ◽  
Phase Changes ◽  
Water Soluble ◽  
Individual Species ◽  
Measured Concentration ◽  
Surface Exchange ◽  
Concentration Difference ◽  
Wet Chemical

Abstract. The aerodynamic gradient method is widely used for flux measurements of ammonia, nitric acid, particulate ammonium nitrate (the NH3-HNO3-NH4NO3 triad) and other water-soluble reactive trace compounds. The surface exchange flux is derived from a measured concentration difference and micrometeorological quantities (turbulent exchange coefficient). The significance of the measured concentration difference is crucial for the significant determination of surface exchange fluxes. Additionally, measurements of surface exchange fluxes of ammonia, nitric acid and ammonium nitrate are often strongly affected by phase changes between gaseous and particulate compounds of the triad, which make measurements of the four individual species (NH3, HNO3, NH4+, NO3− necessary for a correct interpretation of the measured concentration differences. We present here a rigorous analysis of results obtained with a multi-component, wet-chemical instrument, able to simultaneously measure gradients of both gaseous and particulate trace substances. Basis for our analysis are two field experiments, conducted above contrasting ecosystems (grassland, forest). Precision requirements of the instrument as well as errors of concentration differences and micrometeorological exchange parameters have been estimated, which, in turn, allows the establishment of thorough error estimates of the derived fluxes of NH3, HNO3, NH4+, and NO3−. Derived median flux errors for the grassland and forest field experiments were: 39% and 50% (NH3), 31% and 38% (HNO3), 62% and 57% (NH4+), and 47% and 68% (NO3−), respectively. Additionally, we provide the basis for using field data to characterize the instrument performance, as well as subsequent quantification of surface exchange fluxes and underlying mechanistic processes under realistic ambient measurement conditions.

scholarly journals Aerodynamic gradient measurements of the NH<sub>3</sub>-HNO<sub>3</sub>-NH<sub>4</sub>NO<sub>3</sub> triad using a wet chemical instrument: an analysis of precision requirements and flux errors

2009 ◽  
Vol 2 (5) ◽  
pp. 2423-2482 ◽  
Author(s):  
V. Wolff ◽  
I. Trebs ◽  
C. Ammann ◽  
F. X. Meixner
Keyword(s):  
Nitric Acid ◽  
Ammonium Nitrate ◽  
Field Experiments ◽  
Phase Changes ◽  
Water Soluble ◽  
Individual Species ◽  
Measured Concentration ◽  
Surface Exchange ◽  
Concentration Difference ◽  
Wet Chemical

Abstract. The aerodynamic gradient method is widely used for flux measurements of ammonia, nitric acid, particulate ammonium nitrate (the NH3-HNO3-NH4NO3 triad) and other water-soluble reactive trace compounds. The surface exchange flux is derived from a measured concentration difference and micrometeorological quantities (turbulent exchange coefficient). The significance of the measured concentration difference is crucial for the significant determination of surface exchange fluxes. Additionally, measurements of surface exchange fluxes of ammonia, nitric acid and ammonium nitrate are often strongly affected by phase changes between gaseous and particulate compounds of the triad, which make measurements of the four individual species (NH3, HNO3, NH4+, NO3–) necessary for a correct interpretation of the measured concentration differences. We present here a rigorous analysis of results obtained with a multi-component, wet-chemical instrument, able to simultaneously measure gradients of both gaseous and particulate trace substances. Basis for our analysis are two field experiments, conducted above contrasting ecosystems (grassland, forest). Precision requirements of the instrument as well as errors of concentration differences and micrometeorological exchange parameters have been estimated, which, in turn, allows the establishment of thorough error estimates of the derived fluxes of NH3, HNO3, NH4+, and NO3–. Derived median flux errors for the grassland and forest field experiments were: 39 and 50% (NH3), 31 and 38% (HNO3), 62 and 57% (NH4+), and 47 and 68% (NO3–), respectively. Additionally, we provide the basis for using field data to characterize the instrument performance, as well as subsequent quantification of surface exchange fluxes and underlying mechanistic processes under realistic ambient measurement conditions.

The availability of potassium in some Tasmanian soils. I. The variability of soil potassium in the field and its fractionation

1960 ◽  
Vol 11 (5) ◽  
pp. 750
Author(s):  
AM Graley ◽  
KD Nicholls ◽  
CS Piper
Keyword(s):  
Nitric Acid ◽  
Hydrochloric Acid ◽  
Soil Type ◽  
Field Experiments ◽  
Sandy Loam ◽  
Water Soluble ◽  
Soluble Form ◽  
Exchangeable Potassium ◽  
Exchangeable Fraction ◽  
Total Potassium

The potassium status of Frodsley sandy loam and some associated soils from the Fingal district, north-eastern Tasmania, has been investigated. Regularly spaced sampling of surface soils on a rectilinear grid pattern disclosed a variability of exchangeable potassium values in the field much greater than recorded for soils elsewhere; even for 3-ft spacings there was a sevenfold range. The need for adequate sampling of experimental areas is stressed. The median value for exchangeable potassium in the A1 horizon of Frodsley sandy loam was 0.31 m-equiv./100 g for "developed" areas and 0.35 m-equiv./100 g for "undeveloped" areas. Values for the A2 horizon were closely correlated with those for the corresponding surface horizon, but only about one-third as high. The amounts in the B horizon tended to approximate to those in the A1 horizon except for soils with high values in the surface. The potassium-supplying capacity of the soils was assessed by fractionation of the potassium into water-soluble, exchangeable, difficultly exchangeable, hydrochloric acid-soluble, and total potassium. In Frodsley sandy loam approximately 35 per cent. of the exchangeable potassium appeared in the water-soluble form, which suggested that there may be moderate losses from this soil by leaching. Ten minutes' boiling with normal nitric acid released only about 90 per cent. more potassium than was present in the exchangeable fraction. Boiling normal nitric acid extracted much less potassium from some samples of this soil type than did cold normal ammonium chloride from others, because of the great variability of exchangeable potassium. Concentrated hydrochloric acid dissolved a further 0.60.7 m-equiv./100 g on the average. These low values for the two latter fractions are taken to indicate the poverty of this soil type in reserves of potassium and, with the relatively low values for the exchangeable fraction, explain the widespread responses to potassium reported in field experiments. Examination of the minerals of the clay fraction of Frodsley sandy loam supported the chemical data in regard to the poor potassium status of these soils. Separation of sand, silt, and clay from the B horizons of two profiles showed that much of the total potassium was present in the coarser fractions of the soil. Type A, a soil associated with Frodsley sandy loam on river terraces, had a similar potassium status. Soils formed on dolerite were significantly higher in all categories of potassium.

scholarly journals Air–surface exchange of gaseous mercury over permafrost soil: an investigation at a high-altitude (4700 m a.s.l.) and remote site in the central Qinghai-Tibet Plateau

2016 ◽  
Author(s):  
Zhijia Ci ◽  
Fei Peng ◽  
Xian Xue ◽  
Xiaoshan Zhang
Keyword(s):  
High Altitude ◽  
Field Experiments ◽  
Tibet Plateau ◽  
Permafrost Soil ◽  
Remote Site ◽  
Water Addition ◽  
Surface Exchange ◽  
Entire Study ◽  
Gaseous Mercury ◽  
Qinghai Tibet Plateau

Abstract. The pattern of air–surface gaseous mercury (mainly Hg(0)) exchange in the Qinghai-Tibet Plateau (QTP) may be unique because this region is characterized by low temperature, great temperature variation, intensive solar radiation, and pronounced freeze-thaw process of permafrost soils. However, air–surface Hg(0) flux in the QTP is poorly investigated. In this study, we performed filed measurements and controlled field experiments with dynamic flux chambers technique to examine the flux, temporal variation and influencing factors of air–surface Hg(0) exchange at a high-altitude (4700 m a.s.l.) and remote site in the central QTP. The results of field measurements showed that surface soils were net emission source of Hg(0) in the entire study. Hg(0) flux showed remarkable seasonality with net high emission in the warm campaigns and net low deposition in winter campaign, and also showed the diurnal pattern with emission in daytime and deposition in nighttime, especially on days without precipitation. Rainfall events on the dry soils induced large and immediate increase in Hg(0) emission. Snowfall events did not induce the pulse of Hg(0) emission, but snow melt resulted in the immediate increase in Hg(0) emission. Daily Hg(0) fluxes on rainy or snowy days were higher than those of days without precipitation. Controlled field experiments suggested that water addition to dry soils significantly increased Hg(0) emission both in short and relatively long timescales, and also showed that UV radiation was primarily attributed to Hg(0) emission in the daytime. Our findings imply that a warm climate and environmental change could facilitate Hg release from the permafrost terrestrial ecosystem in the QTP.

Field experiments comparing ammonium nitrate and ammonium sulphate as top-dressings for winter wheat and grassland

1964 ◽  
Vol 62 (3) ◽  
pp. 377-379 ◽  
Author(s):  
J. R. Devine ◽  
M. R. J. Holmes
Keyword(s):  
Great Britain ◽  
Winter Wheat ◽  
Ammonium Nitrate ◽  
Ammonium Sulphate ◽  
Field Experiments

Ammonium nitrate and ammonium sulphate wore compared as top-dressing applications in thirty-six field experiments on winter wheat and eighty-nine on grassland in various parts of Great Britain in 1956-62. The rates of application were 35-60 lb./acre of nitrogen for winter wheat and 30-100 lb./acre for grassland in one application only.

scholarly journals Mercury vapor air–surface exchange measured by collocated micrometeorological and enclosure methods – Part II: Bias and uncertainty analysis

2015 ◽  
Vol 15 (4) ◽  
pp. 4627-4676
Author(s):  
W. Zhu ◽  
J. Sommar ◽  
C.-J. Lin ◽  
X. Feng
Keyword(s):  
Flux Measurement ◽  
Bowen Ratio ◽  
Vertical Gradient ◽  
Systematic Evaluation ◽  
Data Set ◽  
Surface Exchange ◽  
Concentration Difference ◽  
Vegetation Height ◽  
Gradient Based ◽  
Flux Quantification

Abstract. Dynamic flux chambers (DFCs) and micrometeorological (MM) methods are extensively deployed for gauging air–surface Hg0 gas exchange. However, a systematic evaluation of the precision of the contemporary Hg0 flux quantification methods is not available. In this study, the uncertainty in Hg0 flux measured by relaxed eddy accumulation (REA) method, aerodynamic gradient method (AGM), modified Bowen-ratio (MBR) method, as well as DFC of traditional (TDFC) and novel (NDFC) designs is assessed using a robust data-set from two field intercomparison campaigns. The absolute precision in Hg0 concentration difference (Δ C) measurements is estimated at 0.064 ng m−3 for the gradient-based MBR and AGM system. For the REA system, the parameter is Hg0 concentration (C) dependent at 0.069+0.022C. 57 and 62% of the individual vertical gradient measurements were found to be significantly different from zero during the campaigns, while for the REA-technique the percentage of significant observations was lower. For the chambers, non-significant fluxes are confined to a few nighttime periods with varying ambient Hg0 concentration. Relative bias for DFC-derived fluxes is estimated to be ~ ±10%, and ~ 85% of the flux bias are within ±2 ng m−2 h−1 in absolute term. The DFC flux bias follows a diurnal cycle, which is largely dictated by temperature controls on the enclosed volume. Due to contrasting prevailing micrometeorological conditions, the relative uncertainty (median) in turbulent exchange parameters differs by nearly a factor of two between the campaigns, while that in Δ C measurements is fairly stable. The estimated flux uncertainties for the triad of MM-techniques are 16–27, 12–23 and 19–31% (interquartile range) for the AGM, MBR and REA method, respectively. This study indicates that flux-gradient based techniques (MBR and AGM) are preferable to REA in quantifying Hg0 flux over ecosystems with low vegetation height. A limitation of all Hg0 flux measurement systems investigated is their incapability to obtain synchronous samples for the calculation of Δ C. This reduces the precision of flux quantification, particularly the MM-systems under non-stationarity of ambient Hg0 concentration. For future applications, it is recommended to accomplish Δ C derivation from simultaneous collected samples.

scholarly journals Ammonia Volatilization, Forage Accumulation, and Nutritive Value of Marandu Palisade Grass Pastures in Different N Sources and Doses

Atmosphere ◽  
2021 ◽  
Vol 12 (9) ◽  
pp. 1179
Author(s):  
Darlena Caroline da Cruz Corrêa ◽  
Abmael da Silva Cardoso ◽  
Mariane Rodrigues Ferreira ◽  
Débora Siniscalchi ◽  
Pedro Henrique de Almeida Gonçalves ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Ammonium Nitrate ◽  
Ammonium Sulfate ◽  
Nutritive Value ◽  
Field Experiments ◽  
Accumulation Rate ◽  
Forage Yield ◽  
Neutral Detergent Fiber ◽  
Urea Ammonium Nitrate ◽  
The Impact

The reduction in ammonia (NH3) losses from volatilization has significant implications in forage production. The objective of this study was to evaluate the impact of N fertilizers (urea, ammonium nitrate, and ammonium sulfate) and four doses (0, 90, 180 and 270 kg N ha−1) on N losses by NH3 volatilization, accumulation, and forage chemical composition of Urochloa brizantha cv Marandu. Two field experiments were conducted to measure NH3 losses using semi-open chambers. The forage accumulation and chemical composition were evaluated in the third experiment; the response variables included forage accumulation, crude protein (CP), and neutral detergent fiber (NDF). Compared to urea, ammonium nitrate and ammonium sulfate reduced NH3 losses by 84% and 87% and increased total forage accumulation by 14% and 23%, respectively. Forage accumulation rate and CP increased linearly with the N levels, while NDF contents decreased linearly with the N levels. In both experiments, NH3 losses and forage characteristics were different according to the rainfall pattern and temperature variations. Our results indicate that the use of nitric and ammoniacal fertilizers and the application of fertilizer in the rainy season constitute an efficient fertilizer management strategy to increase forage yield and decrease losses from volatilization of NH3.

Aqueous ammonia compared with other nitrogenous fertilizers as solids and solutions on grass

1968 ◽  
Vol 71 (2) ◽  
pp. 195-203 ◽  
Author(s):  
D. R. Hodgson ◽  
A. P. Draycott
Keyword(s):  
Ammonium Nitrate ◽  
Ammonium Sulphate ◽  
Dry Matter ◽  
Field Experiments ◽  
Aqueous Ammonia ◽  
Single Injection ◽  
Maximum Yield ◽  
Italian Ryegrass ◽  
Dry Matter Yield ◽  
Single Application

SUMMARYField experiments with Italian ryegrass cut four times a year compared aqueous ammonia with ammonium sulphate and with a mixture of ammonium nitrate and urea (equal parts by weight). In 1963 four rates of nitrogen, 224, 448, 672 and 896 lb/acre, were applied as single and split dressings of injected aqueous ammonia, as solid ammonium sulphate and as injected solution of ammonium sulphate. There was little difference in total dry-matter yield between a single injection of aqueous ammonia and the split dressing of solid. Injecting ammonium sulphate solution eliminated scorch caused by single applications of solid supplying 448 lb N/acre or more and gave significantly greater dry-matter yields. A single application of 448 lb N/acre provided enough nitrogen to sustain the response of the grass to the end of the season.In 1964 a single injection of aqueous ammonia was compared with ammonium nitrate/urea applied as solid or solution at 280, 560 and 840 lb N/acre. There was no difference in total dry-matter yield between aqueous ammonia and ammonium nitrate/urea at rates of 560 and 840 lb/acre. At 280 lb/acre a split dressing of solid produced most dry matter. More than 280 lb N/acre was required, therefore, as a single application in spring to last the whole season, but this rate of nitrogen applied as a split dressing was almost sufficient to give maximum yield.In both experiments the seasonal distribution of dry matter was similar for single and split applications except in 1963 when large single injections of ammonium sulphate produced greater yields at the third cut than the split applications. The percentage of nitrogen recovered in the harvested grass decreased as nitrogen rate was increased and was greater from single than split applications. Recovery of nitrogen from aqueous ammonia was less efficient from four injections than one, and was greater in 1964 than 1963 due to better penetration of the sward by injector tines. Least nitrogen was recovered from surface-applied solutions of ammonium nitrate/urea. Regressions of dry-matter yield on nitrogen yield showed that single injections of aqueous ammonia were as efficient as other fertilizers tested.

scholarly journals Analysis of Compositional Variation and Source Characteristics of Water-Soluble Ions in PM2.5 during Several Winter-Haze Pollution Episodes in Shenyang, China

Atmosphere ◽  
2018 ◽  
Vol 9 (7) ◽  
pp. 280 ◽  
Author(s):  
Ye Hong ◽  
Chaoliu Li ◽  
Xiaolan Li ◽  
Yanjun Ma ◽  
Yunhai Zhang ◽  
...  
Keyword(s):  
Ammonium Nitrate ◽  
Water Soluble ◽  
Compositional Variation ◽  
Automobile Exhaust ◽  
Average Mass ◽  
Coal Burning ◽  
Soluble Ions ◽  
Haze Pollution ◽  
Water Soluble Ions ◽  
Complex Pollution

From 18 February to 13 March 2014 and from 17 December 2016 to 27 January 2017, an online analyzer for monitoring aerosols and gases (MARGA) and an online single particle aerosol mass spectrometer (SPAMS) were used to measure and analyze the concentrations and sources of water-soluble (WS) ions in PM10, PM2.5, and gases (NH3, HNO3, HCl), in Shenyang City, China. During the field campaign, nine haze episodes (or smog episodes, total 582 h) were identified, with 960 identified as non-haze periods. The average mass concentrations of PM2.5 and total water-soluble ions (TWSIs) in PM2.5 during haze episodes were 131 μg·m−3 and 77.2 μg·m−3, 2.3 times and 1.9 times the values in non-haze periods, respectively. The average mass concentration of TWSIs in PM2.5 was 55.9 μg·m−3 (accounting for 55.9% of PM2.5 mass loading), 37.6% of which was sulfate, 31.7% nitrate, 20.0% ammonium, 6.6% chloride, 1.9% potassium, 1.4% calcium, and 0.8% magnesium throughout the campaign. Concentrations of sulfate, nitrate, and ammonium (SNA) secondary pollution ions increased rapidly during haze episodes to as much as 2.2 times, 3.0 times, and 2.4 times higher than during non-haze periods, respectively. Diurnal variations during non-haze periods were significant, while complex pollution was insignificant. Based on changes in the backward trajectories and concentrations of WS ions, the hazy episodes were divided into three types: complex, coal-burning, and automobile exhaust pollution. All complex episodes had high concentrations and greater contributions of ammonium nitrate from complex and automobile exhaust pollution, while the contribution of ammonium sulfate from coal-burning pollution was greater than that of ammonium nitrate. The correlation coefficients among SNA species were very high in complex pollution, with nitrate and sulfate the main forms present. The results of principal component analysis (PCA) were related to emissions from burning coal for heating and from long-range transmission in winter. In the case of exhaust pollution, NO3− accounted for the highest percentage of PM2.5, and NH4+ was more closely related to NO3− than to SO42−. Coal-burning pollution was the most common type of pollution in Shenyang. The contribution of sulfate was higher than that of nitrate. Based on PCA, the contribution of coal-burning emissions varied from 36.7% to 53.6% due to industry, soil sources, and other factors.

The Chemical Behaviour and Deposition of Ammonium Nitrate, Nitric Acid and Ammonia

1997 ◽  
pp. 426-432
Author(s):  
Ralph Dlugi ◽  
Lucia Kins ◽  
Thomas Seiler ◽  
Winfried Seidl ◽  
Peter Seifert ◽  
...  
Keyword(s):  
Nitric Acid ◽  
Ammonium Nitrate ◽  
Chemical Behaviour
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