Gray Henderson - Academia.edu (original) (raw)
Papers by Gray Henderson
Chlorite is a ubiquitous mineral in many geologic environments and plays an important role in ele... more Chlorite is a ubiquitous mineral in many geologic environments and plays an important role in elemental adsorption and retention in soils. Chlorite has a 2:1 layer structure consisting of two tetrahedral sheets with an octahedral sheet between them (talc-like layer). The 2:1 layer is charge balanced and hydrogen-bonded by an interlayer of MgOH[sub 6] octahedra (brucite-like layer). The nature of
ACSESS publications, 1995
The links between forest management, soil organic matter, and forest productivity are examined. T... more The links between forest management, soil organic matter, and forest productivity are examined. There are two distinct aspects of a harvesting operation than influence future productivity: the road and skid trail system for extracting timber; and the harvesting ...
but vegetative filter strips have distinct advantages over other erosion control technologies (Ro... more but vegetative filter strips have distinct advantages over other erosion control technologies (Robinson et al., A paired watershed study consisting of agroforestry (trees plus 1996). Normally, interest in the use of agroforestry prac- grass buffer strips), contour strips (grass buffer strips), and control treatments with a corn (Zea mays L.)-soybean (Glycine max (L.) tices and contour grass strips for various
Handbook of Ecotoxicology, Second Edition, 2002
Soil Science Society of America Journal, 2003
Page 1. Root Distribution Relationships to Soil Properties in Missouri Oak Stands: A Productivity... more Page 1. Root Distribution Relationships to Soil Properties in Missouri Oak Stands: A Productivity Index Approach Ranjith P. Udawatta* and Gray S. Henderson ABSTRACT erties of individual horizons (Carmean, 1975). The suffi ...
Soil Science Society of America Journal, 1970
Journal of Environment Quality, 2002
but vegetative filter strips have distinct advantages over other erosion control technologies (Ro... more but vegetative filter strips have distinct advantages over other erosion control technologies (Robinson et al., A paired watershed study consisting of agroforestry (trees plus 1996). Normally, interest in the use of agroforestry pracgrass buffer strips), contour strips (grass buffer strips), and control treatments with a corn (Zea mays L.)-soybean [Glycine max (L.) tices and contour grass strips for various environmental Merr.] rotation was used to examine treatment effects on runoff, benefits relates to their potential to increase infiltration, sediment, and nutrient losses. During the (1991-1997) calibration and reduce runoff, and reduce NPS pollution. subsequent three-year treatment periods, runoff was measured in 0.91-Limited research suggests that properly established and 1.37-m H-flumes with bubbler flow meters. Composite samples filter strips can reduce runoff, sediment load, and NPS were analyzed for sediment, total phosphorus (TP), total nitrogen pollution (Dillaha et al., 1989) although the design fac-(TN), nitrate, and ammonium. Calibration equations developed to tors of such practices have not been clearly defined. predict runoff, sediment, and nutrients losses explained 66 to 97% of The increased infiltration found under natural forests the variability between treatment watersheds. The contour strip and also occurs in agroforestry and with other vegetative agroforestry treatments reduced runoff by 10 and 1% during the filter practices. Multistrata systems, combined with litter treatment period. In both treatments, most runoff reductions occurred in the second and third years after treatment establishment. The
Biogeochemistry, 1988
Changes in vegetation, litter, and soil nutrient content were measured in selected plots on Walke... more Changes in vegetation, litter, and soil nutrient content were measured in selected plots on Walker Branch watershed, Tennessee, from 1972Tennessee, from -73 to 1982. The watershed has been allowed to revert to forest since 1942, before which it consisted of small subsistence farms and woodland pastures. Changes in Ca status were of particular interest because initial nutrient cycling characterizations indicated that net Ca accumulation in vegetation could have caused large decreases in soil exchangeable Ca 2+ within 20 years.
Biogeochemistry, 1988
... Sources, fates, and impacts of nitrogen inputs to terrestrial ecosystems: review and synthesi... more ... Sources, fates, and impacts of nitrogen inputs to terrestrial ecosystems: review and synthesisLINDSAY R. BORING', WAYNE T. SWANK2, JACK B. WAIDE*, GRAY S. HENDERSON3 'School of Forest Resources, University of Georgia, Athens, GA30602; 2 USDA Forest ...
A i -D model lias been used to calculate the 03 depletion expected ~fail nations adhere to the Mo... more A i -D model lias been used to calculate the 03 depletion expected ~fail nations adhere to the Montréal protocol. Assuming estimatesof —JOkt a 'for CBrCIF2and CBrF3 production rates, we calculate a steady-state column O) depletion of —9%for a scenario without increasing N20 and CH4. Approximately 50% of this depletion is attributable to halon release. We suggest that the Montréal
Journal of Environmental Quality, 1990
Soil Science Society of America Journal, 1984
ABSTRACT Seasonal levels of extractable ammonium and nitrate in the sur-face soil of oak-hickory ... more ABSTRACT Seasonal levels of extractable ammonium and nitrate in the sur-face soil of oak-hickory (Quercus spp. and Carya spp.) forest plots subjected to 30 yr of annual and periodic (4-yr) prescribed burning were studied. Laboratory incubations were also carried out for ...
Soil Science Society of America Journal, 1989
... Media tested with each diluent were the standard medium (1 X) (Schmidt and Belser, 1982), and... more ... Media tested with each diluent were the standard medium (1 X) (Schmidt and Belser, 1982), andmedia that were more dilute (0.25 X and 0.1 X). Each medium was prepared from the standard stock solutions outlined in Schmidt and Belser (1982), except the indicator used was ...
J Atmos Chem, 1989
We present 1-D eddy diffusion model calculations of the distributions of propane and acetone in t... more We present 1-D eddy diffusion model calculations of the distributions of propane and acetone in the atmosphere for continental conditions. The magnitude of the surface seasonal variation in propane mixing ratios that we obtain is in general agreement with measurements at the surface and in the free troposphere. A comparison of the absolute values of the model with propane measurements suggests that a larger surface flux than we have used may be more appropriate for continental conditions. The acetone model results for summer conditions that we obtain are also in reasonable accord with measurements. However, we find serious disagreement between the model winter profiles of acetone and the measurements at the tropopause and in the lower stratosphere. The measured values are lower than the model values at 45" N by a factor of 7-30. In addition, it is also surprising that, given the relatively long lifetime of acetone, free tropospheric values of acetone more representative of surface values have not been measured. The results simulating the decay of elevated levels of propane in the upper troposphere caused by rapid convective transport of boundary layer air indicate that propane will be primarily dispersed by transport rather than destroyed photochemically. Thus, the impact on acetone and PAN is minimal.
Clays Clay Miner, 1970
Recurrent reports of analyses of X-ray diffraction data from regularly alternating and nearly reg... more Recurrent reports of analyses of X-ray diffraction data from regularly alternating and nearly regularly alternating structures like rectorite provide opportunity for a descriptive discussion of their nature. MacEwan-transform-based analyses have uniformly shown higher incidence of unlike adjacent layers than would be expected from random distribution.
Crystal Growth Design, 2011
We report a X-ray absorption study at Ti K-and L 2,3 -edges to determine the role of TiO 2 conten... more We report a X-ray absorption study at Ti K-and L 2,3 -edges to determine the role of TiO 2 content as a nucleating agent in glass ceramics. It is found that the local Ti environment is not modified with TiO 2 addition, indicating that medium range organization is responsible for its ability to promote internal versus bulk nucleation. We have identified a Ti coordination change between the nucleation front and the crystallized part of the glass ceramic. These changes correspond to conversion from 5-fold coordinated to 4-fold coordinated Ti in the remaining glassy part, resulting from compositional changes. This reveals that active sites for nucleation could be experimentally detected and that reorganization of the glass matrix during nucleation has a major influence on the ongoing nucleation processes.
Nature, 1992
Ozone destruction in the Arctic boundary layer beings at polar sunrise, continues for the months ... more Ozone destruction in the Arctic boundary layer beings at polar sunrise, continues for the months of March and April, and is strongly associated with levels of filterable bromine which are much greater than during the rest of the year. It is suggested here that sea-salt Br(-) reaches high concentrations in the snow pack during the long polar night and is evolved into the atmosphere as Br2 at polar sunrise. Ordinarily, gas-phase photochemistry would convert Br2 to HBr or brominated organic compounds with consequently little destruction of boundary-layer ozone. It is proposed that the HBr and brominated organic compounds will be scavenged by the ambient aerosols and ice crystals, and that these heterogeneous reactions release B2 back to the atmosphere. It is argued that this cycling of bromine between the aerosol and the gas phase should maintain sufficiently high levels of Br atoms and BrO radicals to destroy ozone.
The Manitouwabing meteorite whose trace constituents have not been previously quantified was anal... more The Manitouwabing meteorite whose trace constituents have not been previously quantified was analyzed for Au, As, Ga, Ge, Ir, Ni, Os, Pd, Pt, Rh, and Ru. The data confirm that it belongs to subgroup IIIA of the IIIAB group and, on the basis of the much higher concentrations of As, Ir, Os, Pt, Rh, and Ru, it is not paired
Chlorite is a ubiquitous mineral in many geologic environments and plays an important role in ele... more Chlorite is a ubiquitous mineral in many geologic environments and plays an important role in elemental adsorption and retention in soils. Chlorite has a 2:1 layer structure consisting of two tetrahedral sheets with an octahedral sheet between them (talc-like layer). The 2:1 layer is charge balanced and hydrogen-bonded by an interlayer of MgOH[sub 6] octahedra (brucite-like layer). The nature of
ACSESS publications, 1995
The links between forest management, soil organic matter, and forest productivity are examined. T... more The links between forest management, soil organic matter, and forest productivity are examined. There are two distinct aspects of a harvesting operation than influence future productivity: the road and skid trail system for extracting timber; and the harvesting ...
but vegetative filter strips have distinct advantages over other erosion control technologies (Ro... more but vegetative filter strips have distinct advantages over other erosion control technologies (Robinson et al., A paired watershed study consisting of agroforestry (trees plus 1996). Normally, interest in the use of agroforestry prac- grass buffer strips), contour strips (grass buffer strips), and control treatments with a corn (Zea mays L.)-soybean (Glycine max (L.) tices and contour grass strips for various
Handbook of Ecotoxicology, Second Edition, 2002
Soil Science Society of America Journal, 2003
Page 1. Root Distribution Relationships to Soil Properties in Missouri Oak Stands: A Productivity... more Page 1. Root Distribution Relationships to Soil Properties in Missouri Oak Stands: A Productivity Index Approach Ranjith P. Udawatta* and Gray S. Henderson ABSTRACT erties of individual horizons (Carmean, 1975). The suffi ...
Soil Science Society of America Journal, 1970
Journal of Environment Quality, 2002
but vegetative filter strips have distinct advantages over other erosion control technologies (Ro... more but vegetative filter strips have distinct advantages over other erosion control technologies (Robinson et al., A paired watershed study consisting of agroforestry (trees plus 1996). Normally, interest in the use of agroforestry pracgrass buffer strips), contour strips (grass buffer strips), and control treatments with a corn (Zea mays L.)-soybean [Glycine max (L.) tices and contour grass strips for various environmental Merr.] rotation was used to examine treatment effects on runoff, benefits relates to their potential to increase infiltration, sediment, and nutrient losses. During the (1991-1997) calibration and reduce runoff, and reduce NPS pollution. subsequent three-year treatment periods, runoff was measured in 0.91-Limited research suggests that properly established and 1.37-m H-flumes with bubbler flow meters. Composite samples filter strips can reduce runoff, sediment load, and NPS were analyzed for sediment, total phosphorus (TP), total nitrogen pollution (Dillaha et al., 1989) although the design fac-(TN), nitrate, and ammonium. Calibration equations developed to tors of such practices have not been clearly defined. predict runoff, sediment, and nutrients losses explained 66 to 97% of The increased infiltration found under natural forests the variability between treatment watersheds. The contour strip and also occurs in agroforestry and with other vegetative agroforestry treatments reduced runoff by 10 and 1% during the filter practices. Multistrata systems, combined with litter treatment period. In both treatments, most runoff reductions occurred in the second and third years after treatment establishment. The
Biogeochemistry, 1988
Changes in vegetation, litter, and soil nutrient content were measured in selected plots on Walke... more Changes in vegetation, litter, and soil nutrient content were measured in selected plots on Walker Branch watershed, Tennessee, from 1972Tennessee, from -73 to 1982. The watershed has been allowed to revert to forest since 1942, before which it consisted of small subsistence farms and woodland pastures. Changes in Ca status were of particular interest because initial nutrient cycling characterizations indicated that net Ca accumulation in vegetation could have caused large decreases in soil exchangeable Ca 2+ within 20 years.
Biogeochemistry, 1988
... Sources, fates, and impacts of nitrogen inputs to terrestrial ecosystems: review and synthesi... more ... Sources, fates, and impacts of nitrogen inputs to terrestrial ecosystems: review and synthesisLINDSAY R. BORING', WAYNE T. SWANK2, JACK B. WAIDE*, GRAY S. HENDERSON3 'School of Forest Resources, University of Georgia, Athens, GA30602; 2 USDA Forest ...
A i -D model lias been used to calculate the 03 depletion expected ~fail nations adhere to the Mo... more A i -D model lias been used to calculate the 03 depletion expected ~fail nations adhere to the Montréal protocol. Assuming estimatesof —JOkt a 'for CBrCIF2and CBrF3 production rates, we calculate a steady-state column O) depletion of —9%for a scenario without increasing N20 and CH4. Approximately 50% of this depletion is attributable to halon release. We suggest that the Montréal
Journal of Environmental Quality, 1990
Soil Science Society of America Journal, 1984
ABSTRACT Seasonal levels of extractable ammonium and nitrate in the sur-face soil of oak-hickory ... more ABSTRACT Seasonal levels of extractable ammonium and nitrate in the sur-face soil of oak-hickory (Quercus spp. and Carya spp.) forest plots subjected to 30 yr of annual and periodic (4-yr) prescribed burning were studied. Laboratory incubations were also carried out for ...
Soil Science Society of America Journal, 1989
... Media tested with each diluent were the standard medium (1 X) (Schmidt and Belser, 1982), and... more ... Media tested with each diluent were the standard medium (1 X) (Schmidt and Belser, 1982), andmedia that were more dilute (0.25 X and 0.1 X). Each medium was prepared from the standard stock solutions outlined in Schmidt and Belser (1982), except the indicator used was ...
J Atmos Chem, 1989
We present 1-D eddy diffusion model calculations of the distributions of propane and acetone in t... more We present 1-D eddy diffusion model calculations of the distributions of propane and acetone in the atmosphere for continental conditions. The magnitude of the surface seasonal variation in propane mixing ratios that we obtain is in general agreement with measurements at the surface and in the free troposphere. A comparison of the absolute values of the model with propane measurements suggests that a larger surface flux than we have used may be more appropriate for continental conditions. The acetone model results for summer conditions that we obtain are also in reasonable accord with measurements. However, we find serious disagreement between the model winter profiles of acetone and the measurements at the tropopause and in the lower stratosphere. The measured values are lower than the model values at 45" N by a factor of 7-30. In addition, it is also surprising that, given the relatively long lifetime of acetone, free tropospheric values of acetone more representative of surface values have not been measured. The results simulating the decay of elevated levels of propane in the upper troposphere caused by rapid convective transport of boundary layer air indicate that propane will be primarily dispersed by transport rather than destroyed photochemically. Thus, the impact on acetone and PAN is minimal.
Clays Clay Miner, 1970
Recurrent reports of analyses of X-ray diffraction data from regularly alternating and nearly reg... more Recurrent reports of analyses of X-ray diffraction data from regularly alternating and nearly regularly alternating structures like rectorite provide opportunity for a descriptive discussion of their nature. MacEwan-transform-based analyses have uniformly shown higher incidence of unlike adjacent layers than would be expected from random distribution.
Crystal Growth Design, 2011
We report a X-ray absorption study at Ti K-and L 2,3 -edges to determine the role of TiO 2 conten... more We report a X-ray absorption study at Ti K-and L 2,3 -edges to determine the role of TiO 2 content as a nucleating agent in glass ceramics. It is found that the local Ti environment is not modified with TiO 2 addition, indicating that medium range organization is responsible for its ability to promote internal versus bulk nucleation. We have identified a Ti coordination change between the nucleation front and the crystallized part of the glass ceramic. These changes correspond to conversion from 5-fold coordinated to 4-fold coordinated Ti in the remaining glassy part, resulting from compositional changes. This reveals that active sites for nucleation could be experimentally detected and that reorganization of the glass matrix during nucleation has a major influence on the ongoing nucleation processes.
Nature, 1992
Ozone destruction in the Arctic boundary layer beings at polar sunrise, continues for the months ... more Ozone destruction in the Arctic boundary layer beings at polar sunrise, continues for the months of March and April, and is strongly associated with levels of filterable bromine which are much greater than during the rest of the year. It is suggested here that sea-salt Br(-) reaches high concentrations in the snow pack during the long polar night and is evolved into the atmosphere as Br2 at polar sunrise. Ordinarily, gas-phase photochemistry would convert Br2 to HBr or brominated organic compounds with consequently little destruction of boundary-layer ozone. It is proposed that the HBr and brominated organic compounds will be scavenged by the ambient aerosols and ice crystals, and that these heterogeneous reactions release B2 back to the atmosphere. It is argued that this cycling of bromine between the aerosol and the gas phase should maintain sufficiently high levels of Br atoms and BrO radicals to destroy ozone.
The Manitouwabing meteorite whose trace constituents have not been previously quantified was anal... more The Manitouwabing meteorite whose trace constituents have not been previously quantified was analyzed for Au, As, Ga, Ge, Ir, Ni, Os, Pd, Pt, Rh, and Ru. The data confirm that it belongs to subgroup IIIA of the IIIAB group and, on the basis of the much higher concentrations of As, Ir, Os, Pt, Rh, and Ru, it is not paired