bluuebunny/crossref_metadata_2025_split huggingface dataset:
Leaf Photosynthesis: The Influence of Environmental Variables
Authors: Incropera Frank P. 
Published: July 2010

AbstractA model is presented for the effects of light intensity and ambient temperature, relative humidity, and carbon dioxide concentration on leaf photosynthesis. The model treats diffusion and chemical processes occurring within the leaf, as well as the transfer of mass and energy between the leaf and its environment. Calculations have been performed for Zea mays L. (maize) which suggest the influence of environmental changes. Although leaf energy exchange processes act to moderate the effect of changes in the atmospheric temperature, a severe cooling trend may cause as much as 20% reduction in photosynthesis. Under most conditions, the rate of photosynthesis is further diminished by a reduction in relative humidity. In contrast, a 20% increase in the atmospheric CO2 concentration, which is projected for the year 2000, will increase photosynthesis by approximately 15%. The calculations also suggest optimum ambient conditions for controlled growth environments, such as a greenhouse. In addition to a saturating light intensity of approximately 700 W/m2, these conditions include a temperature and relative humidity of approximately 30C and 90%, respectively, and a CO2 concentration of approximately 1,500 ppm.
Phytotoxicity in and Metal Uptake from Soil Treated with Metal‐Amended Sewage Sludge
Authors: Cunningham J. D. , Ryan J. A. , Keeney D. R. 
Published: July 2010

AbstractA greenhouse experiment was conducted to evaluate yield and the concentration of Cd, Cu, Cr, Ni, and Zn in corn (Zea mays L.) and rye (Seceale cereal L.) tissue when grown on a soil limed to pH 6.8 and treated with a waste water sludge that had been amended with Cu, Cr, Ni, and Zn salts. Three rates of each metal in all combinations were used. The rates were obtained by adding the appropriate amounts of each metal to a bulk sample of anaerobic digested sludge. After equilibration for 2 weeks, the sludge was air‐dried, and mixed with a sandy loam soil at the rate of 63 metric tons/ha (solids). Corn, rye, and corn, in that order, were grown on the soil for 6 weeks each.Yields decreased as the Cu and Zn concentration of the sludge increased, while Ni had no appreciable effect. Yields were increased significantly as the sludge Cr concentration increased, indicating that Cr may be inhibiting the uptake or translocation of other metals. This was substantiated by tissue analysis which showed that with increasing sludge Cr, tissue concentrations of the other metals decreased. Tissue concentrations of Cu and Zn were consistently >20 and 400 ppm, respectively, and thus were in the range considered toxic to plants. As the sludge concentration of Cu or Zn increased, tissue concentrations of the other metals were increased, and evidence of Cu‐Zn interactions on plant growth and metal concentrations was obtained. The only Cd sources were that in the soil and in the original sludges, yet the Cd concentration of plant tissue increased with increasing Cu concentration.Yield reductions relative to the control were less and tissue concentrations of the metals decreased from the first to the second corn crop, indicating reversion of the metals to less available form with time.
Phytotoxicity and Uptake of Metals Added to Soils as Inorganic Salts or in Sewage Sludge
Authors: Cunningham J. D. , Keeney D. R. , Ryan J. A. 
Published: July 2010

AbstractCrop growth and metal uptake on soil treated with inorganic salts of Cr, Cu, Zn, and Ni were compared with the results obtained when a sewage sludge was amended with these metals before addition to the soil. This mixture was then ground and added to the soil at the rate of 63 metric tons/ha (2.8%) solids. The treatments involving inorganic salts resulted in lower yields and, in general, higher metal concentrations than the equivalent sludge treatments. Lowest yields were generally observed for the high Zn treatment. These findings indicate that caution must be used when attempting to use results of inorganic salt treatments to evaluate phytotoxity and toxic metal uptake from sewage sludge amended soils.
Interaction between Aquatic Plants and Bed Sediments in Mercury Uptake from Flowing Water
Authors: Mortimer D. C. , Kudo Akira 
Published: July 2010

AbstractBed sediment from a known zone in the Ottawa River study area and cuttings of Elodea densa were set out in aquaria in a 24‐day controlled, flowing water experiment. Elodea was planted in sediment and in glass beads, and sediment was exposed with and without plants, all in the same aquaria for 7 days before the addition of mercury with 203Hg. Three concentrations each of mercuric chloride and methyl mercuric chloride were continuously metered into the input water to yield aquarium levels of 0.2, 2, and 10 µg/liter.There was no significant difference in the uptake rate between the two forms of mercury. Uptake was proportional to water concentration over the entire 17‐day exposure period in both plants and sediment. Methyl mercury was more toxic to plant growth in this time interval than inorganic mercury. Elodea growing in sediment absorbed significantly less mercury than Elodea growing in glass beads. Sediment from which the plants had been removed contained about twice as much mercury as plant‐free sediment. The aquarium walls were the largest absorbing compartment in the system and methyl mercury was absorbed more strongly than inorganic mercury. The total recovery of input mercury over the 17 days averaged 91%.
Model Ecosystem Studies of Lead and Cadmium and of Urban Sewage Sludge Containing these Elements
Authors: Lu Po‐Yung , Metcalf Robert L. , Furman Rick , Vogel Raymond , Hassett John 
Published: July 2010

AbstractThe environmental fate and effects of cadmium and lead were studied in a laboratory model ecosystem with a terrestrial/aquatic interface, using silica sand, Bloomfield soil (sandy loam) and Drummer soil (silty clay loam) as substrates. Applications were made directly to the substrates as lead and cadmium chloride and as sewage sludge as a source of heavy metals. The mobilization and incorporation of cadmium and lead into food chain organisms were proportional to sorption capacity of the substrate and were highest in silica sand and lowest in Drummer soil. Following the application of sewage sludge there was clear cut mobilization and transfer of cadmium, copper, lead, and zinc into food chains, alga (Oedogonium cardiacum), daphnia (Daphnia magna), mosquito larva (Culex pipiens quinquefasciatus), snail (Physa), and fish (Gambusia affinis). Cadmium exerted a particularly adverse affect on the various organisms in the model ecosystem and its presence in relatively high levels in sewage sludge could become a limiting factor in its use on soils and for crop production.
Disposal of Beef‐Feedlot Manure: Effects of Residual and Yearly Applications on Corn and Soil Chemical Properties
Authors: Wallingford G. W. , Murphy L. S. , Powers W. L. , Manges H. L. 
Published: July 2010

AbstractLand disposal of beef‐feedlot manure was studied. Annually, beginning in the fall of 1969, feedlot waste was applied to a silty clay loam soil at rates that after 4 years ranged from 114 to 2,750 metric tons/ha of dry manure. Included were three single applications made in the fall of 1969 (residual) that ranged from 123 to 590 dry metric tons/ha. For 3 years, in the spring and fall, surface soil samples and soil cores were taken. Yields of furrow‐irrigated corn (Zea mays L.) forage and plant contents of N, P, K, Ca, Mg, and Na were measured.Chemical composition of manure from a single feedlot varied greatly. Average composition (dry weight basis) of samples collected for 3 years was 20.5% H2O, 0.92% N, 0.52% P, 1.14% K, 0.92% Ca, 0.41% Mg, and 0.26% Na. At all sampling dates electrical conductivities (EC) of extracts from saturated pastes of the surface soil samples from plots receiving yearly manure treatments were linearly related to cumulative tons of applied manure; EC values of more than 10 mmho/cm were recorded for the spring samplings. Both yearly and residual manure treatments caused Na and NO3‐N to move downward accumulating to depths of at least 1 m after 3 years; movement of K and P was restricted to 50 and 30 cm, respectively. Corn‐forage yields were increased by improved soil fertility at the low and intermediate yearly rates, but depressed at the high rates, probably because of salt injury. After 4 years forage yields were still increased on plots that received residual treatments. Uptake of N and P was also depressed at high yearly rates and followed trends similar to those of yield. Yearly rates ranging from 29 to 68 dry metric tons ha−1 year−1 produced near maximum forage yields without causing excessive salt accumulation in the soil.
The Effect of Oil Pollution of Soil on Germination, Growth and Nutrient Uptake of Corn
Authors: Udo E. J. , Fayemi A. A. A. 
Published: July 2010

AbstractThe effect of crude oil pollution of soil on the growth of plants and uptake of nutrients was investigated by growing corn (Zea mays L.) on a soil polluted by crude petroleum. The levels of the crude oil application varied from 0 to 10.6% by weight of soil. Three corn crops were raised in succession, each for a period of 6 weeks, in the same soil. The yields and plant contents of N, P, K, Ca, Fe, and Mn were determined. The soil was analyzed for organic C, total and available N, extractable P, and exchangeable K, Ca, Fe, and Mn after each cropping. Germination and yields were drastically reduced as the level of pollution increased. At 4.2% crude oil pollution level, the average reductions were 50% and 92% in germination and yield, respectively. The amount of organic C, total N, and exchangeable K, Fe, and Mn increased in the soil with level of crude oil addition, while extractable P, NO3‐N, and exchangeable Ca were reduced. The poor growth was attributed to suffocation of the plants caused by exclusion of air by the oil or exhaustion of oxygen by increased microbial activity, interference with plant‐soil‐water relationships, and toxicity from sulfides and excess available Mn produced during the decomposition of the hydrocarbons.
Factors Influencing Nitrate Transformations in Sediments
Authors: Terry R. E. , Nelson D. W. 
Published: July 2010

AbstractThe effects of environmental and procedural factors (e.g., aeration, size of sample, water/sediment ratio, nitrate concentration, glucose addition, temperature, and sterilization) on denitrification in lake and reservoir sediments were evaluated by incubating nitrate‐amended natural sediments in the laboratory. The standard laboratory procedure adopted for denitrification studies involved the incubation of small samples of sediment (undried) after addition of a nitrate solution. Incubations were conducted at 15C in polypropylene centrifuge tubes. Denitrification in sediment‐water samples was not enhanced by continuously purging samples with helium to create artificial anaerobic conditions. Experiments showed that denitrification rates in sediments could be satisfactorily measured using wet sediment (0.5 g solids) treated with 5 ml of 100 ppm nitrate‐15N solution and incubated for 5 to 10 days. The small sample size facilitated sample preparation, extraction of inorganic forms of N and micro‐Kjeldahl analysis of sediment.Even though glucose additions enhanced denitrification by 25 to 30%, unamended sediments contained sufficient available organic‐C for near maximal rates of denitrification. Denitrification in sediments increased with increasing temperature over the range of 5 to 23C. However, significant denitrification occurred at temperatures as low as 5C. Nitrate was not lost from sterilized sediment samples, therefore, the nitrogen transformations observed in unsterilized sediment samples were mediated by biological mechanisms.The evaluation of factors affecting denitrification in sediment shows that the environmental conditions likely to exist in natural sediments are suitable for denitrification. Anaerobiosis and the high organic matter of most sediments create an ideal environment for microbial denitrification. The levels of nitrate in surface water may in part be controlled naturally by denitrification in sediments.
Dinitroaniline Herbicides in Soils
Authors: Helling Charles S. 
Published: July 2010

AbstractThe behavior and fate of dinitroaniline herbicides in the soil environment is reviewed. This rapidly expanding class of herbicides is used particularly for pre‐emergence control of annual grasses and small‐seeded broadleaf weeds in cotton (Gossvpium hirsutum L.), soybeans [Glycine max (L.) Merr.], and peanuts (Arachis hypogaea L.). All dinitroaniline herbicides in use are 4‐alkyl (or ‐sulfonyl)‐2,6‐dinitro‐N,N‐(mono‐ or disubstituted) anilines, characterized by very low water solubility and basicity. Volatilization from surface applications to moist soil is substantial for trifluralin, benefin, and profluralin, but is low for nitralin and oryzalin. In water and on dry soil, dinitroanilines exposed to sunlight degrade to photoproducts that are often polar and include dealkylated and cyclic intermediates. Such photodecomposition greatly reduces bioaccumulation of dinitroanilines by aquatic organisms.Physico‐chemical behavior of dinitroanilines in soils or sediments is influenced by volatilization and by strong soil adsorption. Nitralin and oryzalin may leach slightly, but dinitroanilines are essentially immobile. Short range diffusion may be important for herbicide efficacy or loss from the soil surface. Both solution and vapor phase transport components affect trifluralin diffusion; the extent and balance of diffusion are strongly affected by soil temperature, moisture, and bulk density. Phytotoxicity apparently cannot be correlated with adsorption strength, but may be related to volatility. Physical loss from soil, unless incorporated, is by sediment runoff and by volatilization.Dinitroaniline herbicides degrade more rapidly in anaerobic, than aerobic soil. Metabolites are numerous and often resemble those produced by the photolytic mechanisms of dealkylation and cyclization. A gradually increasing quantity of residue becomes associated with soil organic matter, as bound residue. For normal use rates, persistence in soils ranges from about 2–3 months, for oryzalin and dinitramine, to 5–6 months for benefin and trifluralin. Persistence increases with decreasing soil temperature and moisture content; seasonal carryover sometimes occurs. Limited evidence suggests that dinitroanilines produce no lasting effect on soil microbial processes.
Retention of Metals in Sewage Sludge I: Constituent Heavy Metals
Authors: Lagerwerff J. V. , Biersdorf G. T. , Brower D. L. 
Published: July 2010

AbstractSewage sludge from Baltimore, Md. was compared to that of Washington, D.C. in terms of the tendency to release heavy metals under a variety of circumstances. Total and 1.0N HCl‐extractable concentrations of Cd, Cu, Pb, and Zn were determined by atomic absorption spectrophotometry. Fractionation of the metals by leaching columned samples of Baltimore sludge, with either a CaCl2 solution or H2O over extended periods of time, showed Cd and especially Zn were more leachable than Cu and Pb. Except for Pb, leachability of the metals was much lower in the sludge from Washington, D.C. than in the Baltimore sludge. Regarding the sign of charge of Cu species as a function of the progression of leaching of Baltimore sludge, anionic and, especially, amphoteric species increased, as cationic ones decreased. When aqueous sludge leachates were stored for 13 months at 5C, amphoteric Cu strongly increased, while all other Cu species decreased. In contrast, nearly all Zn species in the stored leachates were cationic. When sludge samples were subjected to simulated weathering by stirring with either H2O2 in a number of concentrations, or H2O, followed by steambath drying, the extractability of heavy metals with H2O and 0.01N HCl increased. Extractability of Cu increased more than that of Cd or Zn, suggesting that the stability of the amphoteric Cu species depended strongly on acidity. Because of the H2O2 treatments, the cation exchange capacity of the sludges diminished by 15 to 25% depending on their origin, although no C was lost.Compared with Washington, D.C. sewage sludge, Baltimore sludge had a greater heavy metal contaminating potential for soil amended with it.
Persistence of Fecal Coliform Indicator Bacteria on Alfalfa Irrigated with Municipal Sewage Lagoon Effluent
Authors: Bell R. G. 
Published: July 2010

AbstractFecal coliforms on alfalfa plants (Medicago sativa L.) irrigated with sewage lagoon effluent were completely destroyed by exposure to 10 hours bright sunlight. No decrease in numbers was observed in the absence of bright sunlight under cool, damp, overcast conditions. Exposure to 10 hours bright sunlight was adequate to destroy all the fecal coliforms present in raw sewage.In the event that sewage treatment failures such as lagoon short‐circuiting occurred while alfalfa was being irrigated with sewage effluent in the semiarid prairie region, livestock would be adequately protected from possible salmonella and enteropathogenic Escherichia coli infection if at least 2 sunny days elapse between the cessation of effluent irrigation and the consumption of the forage.
Evaluation of Methods for Preserving the Levels of Soluble Inorganic Phosphorus and Nitrogen in Unfiltered Water Samples
Authors: Klingaman E. D. , Nelson D. W. 
Published: July 2010

AbstractSeveral methods for preserving the levels of soluble inorganic phosphorus (SIP), ammonium, and nitrate in surface runoff, tile drainage water, and river water were evaluated. The best overall technique for preservation of water samples for P and N analysis appeared to be storage at subzero temperatures. The SIP concentration in samples was also stabilized by addition of HgCl2 (40 mg/liter) and storage at 4C; however, the ammonium and nitrate levels in samples were not preserved for long periods of time (12 weeks) by this technique. The soluble inorganic N levels in water samples were preserved by addition of phenylmercuric acetate (20 mg/liter) and storage at 4C, but use of this procedure increased the SIP concentration in some samples during storage. Storage of samples at 4C or 23C without addition of a chemical preservative resulted in large changes in soluble inorganic P and N contents.
Nitrogen and Phosphorus Losses from Winter Disposal of Dairy Manure
Authors: Klausner S. D. , Zwerman P. J. , Ellis D. F. 
Published: July 2010

AbstractAn evaluation of surface runoff losses of inorganic nitrogen and total soluble phosphorus from fields receiving winter applications of dairy manure was conducted. Runoff losses, as derived from natural precipitation, were accumulated for the time period 1 Jan. to 31 Mar. for 3 consecutive years. The influence of rate of manure application (35, 100, and 200 metric tons/ha) and climatological variability within and between years was of primary importance. Average runoff values of inorganic nitrogen for the three rates of application were 16, 1, and 0.2 kg/ha for 1972, 1973, and 1974, respectively. Phosphorus values averaged 3.5, 0.7, and 0.01 kg/ha for the 3 respective years. Adverse weather conditions during the winter application in 1972 were largely responsible for increased nutrient discharges in runoff. Results indicated that manure disposal during active thaw periods can result in increased nutrient losses. Losses were minimized when manure was applied and then covered with snow, melting at a later date. The 35 metric tons/ha rate of application, applied on frozen soil and then covered with snow, resulted in nutrient losses that differed little from areas that received no manure.
Effect of Dairy Cattle Manure on Millet and Rye Forage and Soil Properties
Authors: Mugiwra L. M. 
Published: July 2010

AbstractDairy cattle manure was incorporated in plots of Decatur silty clay loam (Thermic Rhodic Paleudults) at rates of 0, 22, 44, 89, 178, and 267 metric tons/ha (dry weight) for 3 successive years. Pearl millet (Pennisetum americanum L. K. Schum) was grown in summer and was clipped twice and ‘Wrens Abruzzi’ rye (Secale cereale L.) was grown as a winter cover crop.Annual applications of 22 and 44 metric tons/ha manure were more effective than higher rates in stimulating millet growth, but rye forage yields were generally not influenced by manure application. The uptake of P, Ca, and Mg tended to level out at 44 tons/ha, but the removal of N, K, NO3‐N, and Na by millet and rye from the soil continued to increase with the rate of manure applied. The high rates of manure caused excessive accumulation of nitrate in plants and soils. The range of nitrate‐N in millet was 5,037 to 8,675 ppm at 178 and 267 metric tons/ha compared with 602 to 4.010 ppm on the NPK check plots. Nitrate‐N in the top 90 cm of the soil over the 3 years averaged 840 kg/ha at 178 and 267 tons/ha compared with 239 kg/ha of NO3‐N on the check. Dry matter and soil and plant analyses indicated that 44 metric tons/ha was the highest annual application rate of manure that could be used on this soil with consistent increases in plant growth and nutrient uptake and without excessive nitrate accumulation in soils and plants.
Phosphorus Balance in Sewage Effluent Treated Soils
Authors: Kardos L. T. , Hook J. E. 
Published: July 2010

AbstractFour field sites which have been irrigated with various levels of secondary treated sewage effluent for 9 to 11 years have been examined for phosphorus content in soil water extracted with suction lysimeters. The cornfield site on Hublersburg clay loam irrigated with effluent had an average P concentration of 0.329, 0.070, and 0.046 mg/liter in soil water at 15, 60, and 120 cm respectively compared to 0.043, 0.046, and 0.037 mg/liter, respectively, under an adjacent fertilized, but unirrigated control. Year round application of effluent including 2 years of effluent plus sludge to reed canarygrass (Phalaris arundinacea L.) on Hublersburg clay loam resulted in average soil water concentrations of 0.170, 0.100, and 0.052 mg P/liter at 15, 60, and 120 cm, respectively.In an abandoned field on Hublersburg clay loam where no P was removed by crops, P concentrations were 0.140, 0.103, and 0.076 mg P/liter for the treated plot and 0.038, 0.047, and 0.042 mg P/liter for the control at 15, 60, and 120 cm, respectively. Only the 15‐cm depth had significantly higher P concentrations in the treated plot. A hardwood forest located on a Morrison sandy loam soil was irrigated year round. Phosphorus concentrations in soil water were 0.349, 0.080, and 0.087 mg/liter for the treated vs. 0.059, 0.039, and 0.039 for the control at 15, 60, and 120 cm, respectively. Leaching losses were calculated from concentration of P in soil water at 120 cm and from leaching volume which was rainfall plus irrigation minus potential evapotranspiration. Over all years of treatment no site had leaching losses of > 3% of the total applied.