bluuebunny/crossref_metadata_2025_split huggingface dataset:
Determining Phytotoxic Pesticide Interactions in Soil
Authors: Nash Ralph G. , Jansen Leonard L. 
Published: July 2010

AbstractMethods of determining and describing total phytotoxic actions resulting from pesticides combined in soil have not always been appropriate. The best design appears to be a simple factorial. The criteria selected for analysis should be in a form suitable for statistical evaluation. Regression estimate analysis can identify, characterize, and express magnitude of a physiological interaction. An analysis of variance indicates only the presence of an interaction, Duncan's Multiple Range Test identifies an interaction, and Colby's method indicates magnitude of differences. The regression estimate analysis overcomes some of the statistical and interpretive limitations of the heretofore used Duncan's Multiple Range Test and Colby's method for phytotoxic interactions.
Interactive Effects of Salinity and Ozone on Growth and Yield of Garden Beet
Authors: Ogata Gen , Maas E. V. 
Published: July 2010

AbstractThe interactive effects of root media salinity and ambient ozone on injury, growth, and yield of garden beets (Beta vulgaris L.) were determined under controlled environmental conditions. Plants were grown in nonsaline and saline nutrient solution cultures having osmotic potentials of −0.4, −4.4, and −8.4 bars, respectively, and were exposed 5 weeks to 0.20 ppm ozone for 0 to 3 hours/day.Growth of the nonsaline beet plants were not significantly affected by 0.20 ppm ozone until exposure times exceeded 1 hour/day, although foliar injury in the form of a reddish‐purple stipple had developed on mature leaves. Longer ozone exposures produced severe leaf necrosis and reduced the growth of tops and storage and fibrous roots as much as 50, 40, and 67%, respectively. In contrast, foliar ozone injury on plants grown in saline media developed more slowly and the growth of both tops and roots were relatively unaffected by ozone exposures of up to 3 hours/day. Some reduction in yield of storage roots did occur at −4.4 bars osmotic potential when plants were exposed to ozone for 3 hours/day. However, the beneficial effect of salinity in reducing ozone damage was offset by the suppressive effect of salinity on the yield of the storage root. Dry weights of the storage root were reduced nearly 25% at −4.4 bars osmotic potential.
Inhibition of Apparent Photosynthesis by Air Pollutants
Authors: Bennett Jesse H. , Hill A. Clyde 
Published: July 2010

AbstractThe reversible effects of hydrogen fluoride, sulfur dioxide, and chlorine exposures on net carbon dioxide absorption rates (apparent photosynthesis) of alfalfa (Medicago sativa L.) and barley (Hordeum vulgare L.) plants were studied. Pollutant exposures required (i) to reversibly depress CO2 uptake rates and (ii) to cause cellular necrosis in the leaves were appraised. Plant responses to these air pollutants were compared with responses observed from previous equivalent studies with ozone, nitric oxide, and nitrogen dioxide. The experimental data show that CO2 uptake could be reversibly suppressed by exposure dosages of these pollutants which did not cause cellular destruction in the leaves. However, except for the nitrogen oxides, some necrosis resulted from treatments which depressed CO2 uptake rates more than 25–60% (depending upon the pollutant) by the end of 2‐hour fumigation trials.The six air pollutants can be ranked in the following order according to the relative amounts that plant CO2 uptake rates were depressed by the end of 2 hours of pollutant exposure: HF > 03 ≥ Cl2 > SO2 > NO2 > NO. Carbon monoxide was also tested but did not measurably reduce plant CO2 uptake when applied in concentrations ranging up to 80 ppm. The phytotoxicants ranked in essentially the reverse order when compared on the basis of the rapidity that CO2 uptake was suppressed as a function of exposure time. Nitric oxide treatments caused very rapid reductions in the plant CO2 uptake rates during the first hour of exposure. By this time, plant uptake rates had attained new (depressed) steady‐state equilibrium levels which were then maintained over the remainder of the expo,sure periods. Hydrogen fluoride treatment induced much more gradual reductions in plant CO2 uptake rates throughout the test periods. Plant responses to the other pollutants, SO2, NO2, Cl2, and O3, were intermediate between those caused by NO and HF.The experimental plants were fumigated after steady‐state CO2 exchange rates were established and the percent reduction in the CO2 uptake (along with the rates of recovery) were determined. The investigations were conducted in two identical internalrecirculating environmental chambers (control and treatment chambers) designed to precisely control and continuously monitor light, temperature, wind parameters, relative humidity, and gas exchange rates.
The Effect of Flooding on Moth Fly Larvae and Zooglea in a Sewage Trickling Filter System
Authors: Callahan James T. , Bailey Richard L. 
Published: July 2010

AbstractPopulations of larval flies, particularly Psychoda alternata, are considered to be important to efficient BOD removal in sewage trickling filter systems. This importance arises from their grazing upon the zooglea which coats the filter substrate with the result that the zooglea is kept in a growth phase. Filter flooding is carried out to control the resident population of adult flies. It was hypothesized that the flooding routine also removes significant proportions of the larval fly population and the zooglea—effects which could be detrimental to the efficiency of a filter.In order to assess the effects of filter flooding on the fly larvae and the zooglea, preflood and postflood samples were taken in such a filter in Athens, Georgia. On each of three dates before flooding and on the 3 days immediately after flooding, the filter was sampled for larvae and zooglea at 30.48 cm intervals to a total depth of 121.92 cm. Comparison of the preflood and postflood samples showed that both the larval fly population and the zooglea were significantly reduced by the flooding.The data from the samples were extrapolated to the total volume of the filter bed. Losses from the filter attributable to flooding were estimated to be 1.6 × 108 individual larvae (more than 59% of the preflood total) and 660 kg of zooglea (approximately 47% of the preflood biomass).
Nitrate Uptake Effectiveness of Four Plant Species
Authors: Warncke D. D. , Barber S. A. 
Published: July 2010

AbstractLittle information is available on the characteristics of plant roots that determine their effectiveness in nitrate uptake. The effectiveness of nitrate uptake of corn (Zea mays L.), soybeans (Glycine max L.), sorghum (Sorghum bicolor L.), and bromegrass (Bromus inermus L.) intact roots were investigated in nutrient solution culture. The maximum uptake rate per centimeter of root for corn occurred at 10 mM, for sorghum at 2.4 mM, and for bromegrass at 0.8 mM. Increasing the nitrate level above 1.0 mM did not increase the growth rate during the first 3 weeks for any of these species.The minimum level to which the plant roots reduced the nitrate concentration was 1.7, 2.7, 2.4, and 1.4 µM for forage sorghum, grain sorghum, soybeans, and bromegrass, respectively. Three cultivars of corn were compared. Two reduced the nitrate level to 2 µM and the third to 4 µM.The results of this research indicate that the roots of the species investigated absorbed nitrate of maximum rates from relatively low nitrate concentrations provided the concentration was maintained. Also, the degree of reduction in nitrate level where nitrate in solution was not maintained indicated that these plant roots had the absorptive capacity to reduce solution nitrate to concentrations of 4 µM or less.
Redox Potentials in Soil Columns Intermittently Flooded With Sewage Water
Authors: Whisler F. D. , Lance J. C. , Linebarger R. S. 
Published: July 2010

AbstractPlatinum blacked, platinum wire redox potential probes detected the possibility of denitrification when properly placed in soil columns intermittently flooded with secondary sewage effluent. The evolution of gases from the flooded soil column containing 98% N2 verified the detection. When additional soluble carbon was added to the sewage water, the redox potential dropped to more negative values (−200 mV) than when ordinary sewage water (+200 mV) was used, indicating that the oxidation states of other elements besides nitrogen were changing. The probes functioned for as long as 6 months in place without loss of sensitivity.
Persistence of Salmonellae in Poultry Excreta
Authors: Berkowitz J. H. , Kraft D. J. , Finstein M. S. 
Published: July 2010

AbstractLand application of animal residues containing large numbers of viable pathogenic microorganisms is not an acceptable practice. Information is needed upon which to base storage guidelines to ensure extensive pathogen dieoff. Salmonellae inoculated into samples of poultry excreta declined to very low numbers or disappeared within a month, as judged by a specific most‐probable‐number procedure. The decline was usually preceded by a period of growth, however. Overall reductions of 99% were achieved, on the average, in 19 days when incubation was at 9 to 12C, in 11 days at 18 to 20C, and in 3 days at 30C. Although drying excreta at room temperature killed 99.5% of the inoculated cells, survivors persisted for relatively long periods of time. Storage of undried excreta is an effective means of killing salmonellae.
Toxicity of Copper to Zooplankton
Authors: McIntosh A. W. , Kevern N. R. 
Published: July 2010

AbstractThe toxicity of copper sulfate (CuSO4·5H2O) to zooplankton was studied. Bioassays on Daphnia pulex and Cyclops sp. yielded 96‐hour TLm values of 0.096 and 225.0 ppm, respectively. A treatment of 3 ppm copper sulfate to an outdoor pond was followed by a depression of cladoceran and rotifer populations. Addition of 3 ppm copper sulfate to a second pond occurred when cladoceran numbers were low; however, a combination of oxygen depletion, H2S production and released copper from large masses of decomposing Chara apparently suppressed rotifer, copepod, and cladoceran populations. Treatment of 1 ppm copper sulfate to a third pond produced no discernible effects on cladocera. Stomach analyses conducted on green sunfish (Lepomis cyanellus R.) indicated that the fish shifted to alternate food sources when cladocera disappeared from affected ponds.
Elemental Composition of Particulates Near a Beef Cattle Feedlot
Authors: Azevedo J. , Flocchini R. G. , Cahill T. A. , Stout P. R. 
Published: July 2010

AbstractThe elemental compositions of dusts captured near a beef cattle feedlot were examined for the purpose of determining whether manure dusts could be identified in the presence of background dusts using alpha‐excited X‐rays.Large quantities of particulates greater than 17 µm in diameter were caught within the feedlot, but concentrations of these large particulates downwind of the lot were equal to or less than upwind levels.High ratios of P, S, Cl, K, and Ca to Si distinguished feedlot dusts to greater than 2 µm background particulates. For small particulate sizes (less than 2 µm), feedlot dusts were characterized by relatively high Cl, K, and Ca to Si ratios. On the fringe of feedlot influence, about 100 m downwind in this case, high K/Si and Ca/Si ratios were the most reliable indicators of manure dust.For the particular environmental conditions during this study in the southern San Joaquin Valley of California, feedlot dusts were not detected at a distance of 750 m downwind. Feedlot dust consists mainly of large particulates that drop out rapidly and locally.
Phthalate Esters in the Environment: Pollutants or Natural Products?
Authors: Mathur S. P. 
Published: July 2010

AbstractIn industry, phthalic acid esters (PAEs) are used mainly for producing plastics. Often, their contribution to the weight of plastics is second only to that of the polymer itself. PAEs have also been reported to be present in biological, geochemical, and hydrological samples. Since indications exist that some PAEs may be toxic to man, and pose a threat to the ecological balance, it is important to know whether the PAEs in the environment are mostly pollutants, or natural products. This review of the literature suggests that the PAEs in our environment are more likely to be pollutants. A need for the characterization of the dynamics of PAEs in nature including their interactions with soil and water microflora is therefore clear and urgent.
Adsorption of Bipyridylium Herbicides by Humic Acid
Authors: Khan S. U. 
Published: July 2010

AbstractThe adsorption of paraquat (1,1′‐dimethyl‐4,4′‐bipyridylium dichloride) and diquat (1,1′‐ethylene‐2,2′‐bipyridylium dibromide) by various cation‐saturated humic acids was investigated. The cation order for increasing adsorption for the two herbicides was nearly the same and followed the sequence: Al3+ < Fe3+ < Cu2+ < Ni2+ < Zn2+ < Co2+ < Mn2+ < H+ < Ca2+ < Mg2+. It was suggested that the colloid geometry of humic material and the shape, size and nature of bipyridylium cation would influence the adsorption of the herbicide. By infrared spectroscopic and potentiometric techniques evidence was procured for the involvement of ion‐exchange and charge transfer mechanisms in the adsorption of bipyridylium herbicides by humic acid.
Land Surface Erosion and Rainfall as Sources of Strontium‐90 in Streams
Authors: Menzel Ronald G. 
Published: July 2010

AbstractStrontium‐90 concentrations in streams from 1958 to 1967 reflected the changing concentrations in rainfall and accumulation on the land surface. Correlation analysis of data from nationwide sampling networks shows that the 90Sr concentration in streams was accounted for, on the average, by 1.7% of the rainout 2 months earlier, and annual erosion of 0.58% of the accumulated 90Sr on the land surface. Direct runoff of 90Sr in preceding rainfall was highest, 2.0 to 2.2%, in the north central and eastern United States, ranging down to no measurable direct runoff in the southwestern United States. Annual erosion of 90Sr from the land surface ranged from 0.75% in the Ohio River Basin to 0.17% in the Missouri River Basin. If one allows for differences in time and area of application, these results for land surface erosion indicate the potential movement of persistent, strongly adsorbed pesticides from large land areas.
Columns Representing Mound‐type Disposal Systems for Septic Tank Effluent: II. Nutrient Transformations and Bacterial Populations
Authors: Magdoff F. R. , Keeney D. R. , Bouma J. , Ziebell W. A. 
Published: July 2010

AbstractCarbon, nitrogen, and phosphorus transformations and bacterial populations were studied in columns representing a mound disposal system. Total‐N, total‐P, and the chemical oxygen demand (COD) of the influent (septic tank effluent) averaged 42, 21, and 257 mg/liter, respectively. The reduced‐N forms present in the influent (NH4‐N and organic‐N) were oxidized to NO3‐N in the aerobic fill and about 32% of the total‐N was lost by denitrification during water passage through the anaerobic silt loam at the bottom of the column. Phosphorus (mainly dissolved orthophosphate) concentrations in column effluents, increased gradually, stabilizing at about 60% of the influent P concentration. Phosphorus removal from the percolating water probably occurred by both sorption and precipitation. The COD of column effluents was very low, indicating essentially complete C removal.After crusting developed and caused permanent ponding the fill became anaerobic, and the column effluent N was mainly NH4‐N. Phosphorus concentrations of the effluent increased gradually with time and reached a constant value of 2 to 6 ppm. The COD of the effluent from the totally anaerobic columns was higher than that from the uncrusted columns.Perforating column walls to more closely simulate field conditions permitted aerobic conditions in the fill after crust development caused continuous ponding. The C, N, and P transformations in the perforated crusted columns were similar to those observed in the nonperforated uncrusted (i.e., aerobic) columns.Fecal indicator bacteria were not detected in any column effluent even though the counts of fecal streptococci and fecal coliform in the influent averaged 3.8 × 104 and 1.7 × 105/100 ml, respectively.
Nitrogen Loss from Manure as Influenced by Moisture and Temperature
Authors: Adriano D. C. , Chang A. C. , Sharpless R. 
Published: July 2010

AbstractSoil temperature and moisture are important in cattle waste management. The effects of these two variables on N losses from different rates of applied manure were studied under greenhouse conditions at two soil moisture (60 and 90% of water saturation percentage, WSP) and two soil temperature (10 and 25C) levels.The manure rate did not have a significant effect on the percentage of loss of applied N. At 10C, the average losses of applied N were 26 and 39%, respectively, for the 60 and 90% moisture levels. Higher losses of 40 and 45% were obtained for the 60 and 90% levels, respectively, at 25C. Results suggest that these losses occurred largely through volatilization of NH3. Under conditions where significant nitrification occurred, there were greater concentrations of electrolytes associated with reduction in pH indicating that leaching of NO3− cannot be divorced from soluble salts in manure disposal areas.With N losses approaching 50% of the applied N, large quantities of N are being volatilized to the atmosphere over large and concentrated dairy and feedlot areas.
Degradation of Trifluralin in Soil Suspensions as Related to Redox Potential
Authors: Willis G. H. , Wander R. C. , Southwick L. M. 
Published: July 2010

AbstractA system for controlling redox potential in soil suspensions was used to investigate the relationship between oxidation‐reduction potential (Eh) and the rate of trifluralin (a‐a‐a‐trifluoro‐2,6‐dinitro‐N,N‐dipropyl‐p‐toluidine) degradation. Redox potentials of +450, +250, +150, +50, 0, and −50 mV were imposed on trifluralinamended (1 ppm oven‐dry weight soil basis) soil suspensions (100 g soil in 300 ml H2O) for 21 days. Results indicated that exclusion of O2 by soil flooding initiated rapid trifluralin degradation only when the Eh decreased below a critical range between +150 and +50 mV. There was no clear‐cut relationship between trifluralin degradation and microbiological respiratory activity (CO2 evolution).If soil flooding is to be a practical cultural technique for accelerating the rate of degradation of persistent pesticides, steps may have to be taken to ensure that soil Eh decreases below a critical value for some required period of time. This may include soil incorporation of a readily available carbon or energy source to stimulate an active soil microbial population to enhance lowering of the soil Eh.
An Automatic Pumping Sampler for Evaluating the Transport of Pesticides in Suspended Sediment
Authors: Parr J. F. , Willis G. H. , McDowell L. L. , Murphree C. E. , Smith S. 
Published: July 2010

AbstractLaboratory tests were conducted to evaluate the utility of an automatic pumping sampler for assessing the transport and concentration of pesticides in suspended sediment. Pesticide‐sedimentwater mixtures were formulated with pesticide‐sediment ratios ranging from 1:15,000 to 1:500. After stirring periods of 10 and 60 min, these formulations were pumped through the sampler and aliquots collected for pesticide analysis. Recovery of DDT, trifluralin, toxaphene, and mirex exceeded 90%, based on their concentrations immediately prior to pumping. Adsorption of pesticides to the various plastic, rubber, and fiberglass sampler components was minimized by the high flow velocity and rapid delivery systems which ensured a short time of contact (seconds) between the sample and internal surfaces. These tests indicate that the sampler is suitable for use in evaluating the transport of relatively water‐insoluble pesticides in suspended sediment.
Effects of Mirex on Litter Organisms and Leaf Decomposition in a Mixed Hardwood Forest in Athens, Georgia
Authors: Lee Beatrice Joy 
Published: July 2010

AbstractMirex (dodecachlorooctahydro‐1,3,4‐metheno‐2H‐cyclobuta [cd] pentalene) in corncob grit bait and in spray form was applied to oak (Quercus alba L.) and dogwood (Cornus florida L.) leaf litter in mesh bags, on 20 5m by 5m plots. Macroarthropod fauna was monitored by capture in pitfall traps, and microarthropod populations were extracted from litter bags and counted. Ant presence on plots was tested by use of blank bait and molasses.Mirex in bait and spray form, and at the two levels applied, caused a significant acceleration in litter decomposition. The two leaf species as expected showed significantly different decomposition rates, and the slope of the ground surface on which the bags were placed was found to influence the decomposition process. The two leaf species differed in the amount of decomposition shown with mirex treatment, dogwood being more affected than oak.Ants were essentially removed from bait and concentrated spray plots up to 79 days, but ants had returned to all plots by the 334th day after treatment. The low spray treatment had no effect on the ant populations.Macroarthropods captured were spiders (Araneida), beetles (Coleoptera), millipedes (Orthomorpha gracilis), scorpions (Scorpionida), and centipedes (Scutigerella immaculata). Little difference was observed with treatment except with centipedes whose numbers appeared to decrease on the bait and concentrated spray plots.Microarthropod populations showed significant differences with treatment, at different times during the experiment, but no overall pattern could be detected that might explain the leaf decomposition acceleration noted with all treatments.Since microarthropod, macroarthropods and microflora are known to be involved in the decomposition, and since neither the microarthropods nor the macroarthropods could account for the change in decomposition then by extrapolation the groups most probably affected by the mirex would be the bacteria and fungi. These organisms were not monitored.It is speculated that mirex could have accelerated decomposition through its ability to induce mixed‐function oxidase systems in the microorganisms. These enzymes are responsible for the breakdown of numerous xenobiotics or foreign compounds. If synthesis of more of these enzymes by fungi and/or bacteria allowed faster metabolism of the plant inhibitor, tannic acid, then decomposition could have received an early boost due to the growth of microorganisms usually limited by tannic acid.
Minimizing the Salt Burdens of Irrigation Drainage Waters
Authors: Rhoades J. D. , Oster J. D. , Ingvalson R. D. , Tucker J. M. , Clark M. 
Published: July 2010

AbstractThe salt burdens of percolated drainage waters resulting from the use of waters, synthesized to represent eight important river waters of the western USA, for irrigation of alfalfa (Medicago sativa L.) in a controlled lysimeter experiment, are presented. These data show that minimizing the quantity of drainage water resulted in the smallest possible return of applied salts in the return flow because: i) it maximizes the precipitation of carbonate minerals and gypsum in the soil, ii) it minimizes soil mineral weathering and the dissolution of salts previously deposited in the soil, and iii) it maximizes the amount of soluble salt diverted in the water that is retained in storage in the soil profile and not returned in the drainage water.