A gas-flow soil core method to measure field denitrification rates

1984 ◽  
Vol 16 (4) ◽  
pp. 323-330 ◽  
Author(s):  
Timothy B. Parkin ◽  
Heinrich F. Kaspar ◽  
Alan J. Sexstone ◽  
James M. Tiedje
Keyword(s):  
Gas Flow ◽  
Soil Core ◽  
Core Method ◽  
Measure Field

Semicontinuous Measurement of Soil Atmosphere Gases with Gas-Flow Soil Core Method

1995 ◽  
Vol 59 (5) ◽  
pp. 1336-1342 ◽  
Author(s):  
M. Swerts ◽  
G. Uytterhoeven ◽  
R. Merckx ◽  
K. Vlassak
Keyword(s):  
Gas Flow ◽  
Soil Core ◽  
Core Method ◽  
Soil Atmosphere

Measurement of N2, N2O, NO, and CO2Emissions from Soil with the Gas-Flow-Soil-Core Technique

2011 ◽  
Vol 45 (14) ◽  
pp. 6066-6072 ◽  
Author(s):  
Rui Wang ◽  
Georg Willibald ◽  
Qi Feng ◽  
Xunhua Zheng ◽  
Tingting Liao ◽  
...  
Keyword(s):  
Gas Flow ◽  
Soil Core

Automated online measurement of N2, N2O, NO, CO2, and CH4 emissions based on a gas-flow-soil-core technique

Chemosphere ◽  
2013 ◽  
Vol 93 (11) ◽  
pp. 2848-2853 ◽  
Author(s):  
Tingting Liao ◽  
Rui Wang ◽  
Xunhua Zheng ◽  
Yang Sun ◽  
Klaus Butterbach-Bahl ◽  
...  
Keyword(s):  
Gas Flow ◽  
Soil Core ◽  
Online Measurement ◽  
Ch4 Emissions

scholarly journals First Record of the Genus Myopias (Hymenoptera, Formicidae) from India, with Description of New Species

2012 ◽  
Vol 46 (1) ◽  
pp. e-33-e-35 ◽  
Author(s):  
H. Bharti ◽  
A. Wachkoo
Keyword(s):  
New Species ◽  
Body Size ◽  
First Record ◽  
Soil Core ◽  
Northwest Himalaya ◽  
Reduced Body ◽  
Core Method ◽  
First Time ◽  
Single Worker

First Record of the Genus Myopias (Hymenoptera, Formicidae) from India, with Description of New Species Myopias shivalikensis Bharti et Wachkoo, sp. n. is described based on a single worker, collected in lower Shivalik range (700 m a. s. l.) of Northwest Himalaya by soil core method. The genus Myopias is recorded for the first time in India. M. shivalikensis is a cryptobiotic species with reduced body size and rudimentary eyes. It is similar to M. nops Willey et Brown, 1983, distinctly differing from all described species of this genus.

scholarly journals N<sub>2</sub>O, NO, N<sub>2</sub>, and CO<sub>2</sub> emissions from tropical savanna and grassland of Northern Australia: an incubation experiment with intact soil cores

2014 ◽  
Vol 11 (6) ◽  
pp. 8399-8442 ◽  
Author(s):  
C. Werner ◽  
K. Reiser ◽  
M. Dannenmann ◽  
L. B. Hutley ◽  
J. Jacobeit ◽  
...  
Keyword(s):  
Gas Flow ◽  
N2o Emission ◽  
Soil Conditions ◽  
N2o Emissions ◽  
Soil Core ◽  
Soil Cores ◽  
Northern Australia ◽  
Total N ◽  
Intact Soil Cores ◽  
Intact Soil

Abstract. Strong seasonal variability of hygric and thermal soil conditions are a defining environmental feature in Northern Australia. However, how such changes affect the soil–atmosphere exchange of nitrous oxide (N2O), nitric oxide (NO) and dinitrogen (N2) is still not well explored. By incubating intact soil cores from four sites (3 savanna, 1 pasture) under controlled soil temperatures (ST) and soil moisture (SM) we investigated the release of the trace gas fluxes of N2O, NO and carbon dioxide (CO2). Furthermore, the release of N2 due to denitrification was measured using the helium gas flow soil core technique. Under dry pre-incubation conditions NO and N2O emission were very low (<7.0 ± 5.0 μg NO-N m−2 h−1; <0.0 ± 1.4 μg N2O-N m−2 h−1) or in case of N2O, even a net soil uptake was observed. Substantial NO (max: 306.5 μg N m−2 h−1) and relatively small N2O pulse emissions (max: 5.8 ± 5.0 μg N m−2 h−1) were recorded following soil wetting, but these pulses were short-lived, lasting only up to 3 days. The total atmospheric loss of nitrogen was dominated by N2 emissions (82.4–99.3% of total N lost), although NO emissions contributed almost 43.2% at 50% SM and 30 °C ST. N2O emissions were systematically higher for 3 of 12 sample locations, which indicates substantial spatial variability at site level, but on average soils acted as weak N2O sources or even sinks. Emissions were controlled by SM and ST for N2O and CO2, ST and pH for NO, and SM and pH for N2.

A SOIL CORE METHOD FOR ESTIMATING N-MINERALIZATION AND DENITRIFICATION DURING COVER CROP DECOMPOSITION

Soil Science ◽  
1997 ◽  
Vol 162 (7) ◽  
pp. 510-517 ◽  
Author(s):  
D. R. Shelton ◽  
A. M. Sadeghi ◽  
G. W. McCarty ◽  
A. R. Isensee
Keyword(s):  
Cover Crop ◽  
N Mineralization ◽  
Soil Core ◽  
Core Method

TEM evaluation of graded SixGe1-x heterolayers

1991 ◽  
Vol 49 ◽  
pp. 894-895
Author(s):  
N. David Theodore ◽  
Mamoru Tomozane ◽  
Ming Liaw
Keyword(s):  
Heterojunction Bipolar Transistors ◽  
Gas Flow ◽  
Field Effect Transistors ◽  
Chemical Vapor ◽  
Dark Field ◽  
Bipolar Transistors ◽  
Structural Quality ◽  
Weak Beam ◽  
Transmission Electron ◽  
And Behavior

There is extensive interest in SiGe for use in heterojunction bipolar transistors. SiGe/Si superlattices are also of interest because of their potential for use in infrared detectors and field-effect transistors. The processing required for these materials is quite compatible with existing silicon technology. However, before SiGe can be used extensively for devices, there is a need to understand and then control the origin and behavior of defects in the materials. The present study was aimed at investigating the structural quality of, and the behavior of defects in, graded SiGe layers grown by chemical vapor deposition (CVD).The structures investigated in this study consisted of Si1-xGex[x=0.16]/Si1-xGex[x= 0.14, 0.13, 0.12, 0.10, 0.09, 0.07, 0.05, 0.04, 0.005, 0]/epi-Si/substrate heterolayers grown by CVD. The Si1-xGex layers were isochronally grown [t = 0.4 minutes per layer], with gas-flow rates being adjusted to control composition. Cross-section TEM specimens were prepared in the 110 geometry. These were then analyzed using two-beam bright-field, dark-field and weak-beam images. A JEOL JEM 200CX transmission electron microscope was used, operating at 200 kV.

Electron Microscopy/Diffraction Study of the Ternary Mn-Er-S System

1990 ◽  
Vol 48 (1) ◽  
pp. 76-77
Author(s):  
A. R. Landa Canovas ◽  
L.C. Otero Diaz ◽  
T. White ◽  
B.G. Hyde
Keyword(s):  
Electron Microscopy ◽  
Gas Flow ◽  
Graphite Crucible ◽  
Nominal Composition ◽  
X Ray Diffraction ◽  
Alumina Crucible ◽  
X Ray ◽  
Intermediate Phases ◽  
Twin Band ◽  
Ar Gas

X-Ray diffraction revealed two intermediate phases in the system MnS+Er2S3,:MnEr2S4= MnS.Er2S3, and MnEr4S7= MnS.2Er2S3. Their structures may be described as NaCl type, chemically twinned at the unit cell level, and isostructural with CaTi2O4, and Y5S7 respectively; i.e. {l13} NaCl twin band widths are (4,4) and (4,3).The present study was to search for structurally-related (twinned B.) structures and or possible disorder, using the more sensitive and appropiate technigue of electron microscopy/diffraction.A sample with nominal composition MnEr2S4 was made by heating Mn3O4 and Er2O3 in a graphite crucible and a 5% H2S in Ar gas flow at 1500°C for 4 hours. A small amount of this material was thenannealed, in an alumina crucible, contained in sealed evacuated silica tube, for 24 days at 1100°C. Both samples were studied by X-ray powder diffraction, and in JEOL 2000 FX and 4000 EX microscopes.

Sign in / Sign up

Export Citation Format

Share Document