bluuebunny/crossref_metadata_2025 huggingface dataset:
Sorption and Release of Cadmium by Some Sewage Sludges
Authors: Riffaldi R. , Levi‐Minzi R. , Saviozzi A. , Tropea M.
Published: July 2010

Sorption and release of Cd were determined in nine sewage sludges from Tuscany, Italy. The Cd adsorption data were in agreement with both the linear sorption isotherm and the Langmuir equation. The average of calculated adsorption maxima was about 50% of the mean CEC value, indicating that exchangeable cations present in the sludges were more effective in competing with the Cd ion for exchange sites. The calculated Langmuir adsorption maxima were found significantly correlated with fulvic acid C content and carboxyl and phenolic hydroxyl groups of fulvic acids.

The release of Cd retained at two initial concentrations as a function of different extraction solutions was indagated. Extraction experiments showed that Cd may be held in sludges by more than one type of site and that the strength of bonding decreases as the total Cd increases. Cadmium was retained mainly by exchange and complexing sites, the former assuming a relatively more important role as cadmium adsorption increased.

The effect of different exchangeable cations on the sorption of Cd by sludges was also studied. The amounts of Cd sorbed on the sludge surfaces decreased in the order: Ca‐sludge > untreated sludge > Fe‐sludge = Al‐sludge.
Silage Corn Uptake of Sludge‐Applied Zinc and Cadmium as Affected by Soil pH
Authors: Pepper I. L. , Bezdicek D. F. , Baker A. S. , Sims J. M.
Published: July 2010

Liming is often recommended to control metal uptake in plants. In western Washington, where silage corn (Zea mays L.) is often fed to dairy cattle, studies were conducted to determine the effect of liming on the uptake of Zn, and especially Cd from land‐applied sewage sludge. Two soils, a Sultan silt loam and a Puyallup fine sandy loam were amended annually for 2 y with anaerobically digested sewage sludge, and seeded to silage corn. Half of the plots were limed, which increased soil pH from 4.6 to 6.5 for both soils. In general, liming reduced Zn uptake in most corn tissues, whereas Cd uptake was generally unaffected. Concentration of Zn and Cd in corn leaves from both soils increased significantly with increased sludge rate. Liming significantly lowered leaf Zn, although leaf Cd was not significantly decreased by liming. In fact, at higher sludge application rates, leaf Cd was greater from limed than unlimed plots for the Puyallup soil in 1976. Kernel Zn and Cd concentrations for both soils generally increased with sludge rate. For the Sultan soil, kernel Cd concentration at silage harvest was similar, regardless of lime treatment, whereas Cd values for the limed Puyallup soil increased significantly over those from unlimed soil in 1976. For both soils, Cd and Zn concentrations followed the order: leaves > stover > cobs > kernels. Leaf and DTPA‐extractable Zn/Cd ratios from limed plots were lower than those from unlimed plots. These results suggest that liming to pH 6.5, as recommended in a number of sludge application guides, would not reduce Cd uptake by corn in the soils studied.
Managing Runoff from a Small, Paved Beef Feedlot
Authors: Edwards W. M. , Owens L. B. , White R. K.
Published: July 2010

Each year for 3 y, 56 steer calves were fed to market weight on a corn‐silage and shelled‐corn ration in a 243‐m2 paved lot. Storm runoff was measured and sampled as it left the feedlot, and again after it passed through a shallow, concrete settling basin and two consecutive 30 m long by 4.5 m wide sod filter strips.

Storm runoff amounts and transport of TS (total solids), COD (chemical oxygen demand), BOD5 (5‐d biological oxygen demand), N (total nitrogen), and P (total phosphorus) were smaller during the fall and winter months, when the steers were small and being fed silage than during May through July, when the animals were larger and eating shelled corn. The settling basin reduced transport of TS and COD by about 55%, while retaining only 35–40% of the BOD5, N, and P. Total reduction of all parameters was increased to 80–90% in the filter strips. The basin was more effective in large storm events, and the filter strips were more effective when the basin was slowly drained after settling of the settleable solids. Rainfall on the filter strips reduced the concentration of all parameters during large storms, and infiltration during other events reduced transport to downstream areas.
Forage‐Corn Response to Rice‐Mill Wastes and Fertilizer
Authors: Omaliko C. P. E. , Agbim N. N.
Published: July 2010

A method for disposing of rice‐mill wastes is needed to avoid their pollution and fire‐hazard potential. Two greenhouse experiments were conducted to determine the effects of rice shavings and rice husks on forage‐corn (Zea mays L.) production in two soils.

In Experiment I, rice (Oryza sativa L.) shavings were applied at rates of 0, 75 000, and 150 000 kg/ha with or without additions of nitrogen (N), nitrogen and potassium (NK), nitrogen, phosphorus, and potassium (NPK), or poultry droppings (PD). The residual effects of these treatments, involving in some cases a further application of N, were also evaluated.

Corn top and root yields were at least doubled with rice shavings application. Highest yields were obtained with rice shavings plus NPK or PD applied at a rate equivalent to 100 kg/ha. Additions of either N or K only did not affect yield. Although yields differed on the two soils, the responses to treatments were similar.

In Experiment II, rice husks and shavings were compared in the presence or absence of N and NPK fertilizers. In the absence of fertilizer, there were no yield differences between the two; otherwise, rice husks at 150 000 kg/ha were superior to rice shavings.

These results suggest that under the conditions of this study, the rice waste‐soil system had enough N to support an initial cropping to corn, and P was the major limiting nutrient. Poultry droppings were as good as any of the feritlizer combinations used. Although not investigated, a significant component in the yield improvement may have resulted from the effects of these wastes on the soils' physical properties. The use of these wastes for corn production would, in addition to increasing yield, eliminate waste disposal problems without creating environmental hazards.
Effects of Experimental Variables on 2,4,5‐T Adsorption‐Desorption in Soil
Authors: Koskinen W. C. , Cheng H. H.
Published: July 2010

The effects of different experimental conditions on characteristics of weak acid pesticide adsorption‐desorption in soil was examined using 2,4,5‐T (2,4,5‐trichlorophenoxyacetic acid) as the test compound in a Palouse silt loam soil (Pachic Ultic Haploxerolls). The soil was equilibrated with 2,4,5‐T solutions ranging in concentration from 0.1 to 196 µmol/L, using different ionic strengths of aqueous solution, soil/solution ratios, temperatures, and soil pretreatments. The data for all adsorption experiments fit the Freundlich equation and, depending on the experimental conditions, the adsorption constant Kf ranged from 3.6 to 18.8, while 1/n varied from 0.80 to 0.92. Increasing the salt concentration of the aqueous solution from 0 to 0.1N CaCl2 increased Kf by a factor of 3.9. Changing the soil/solution ratio from 1:1 to 1:3.3 increased Kf by a factor of 1.5. Decreasing the equilibration temperature from 35 to 5° C increased Kf by a factor of 1.3. Preequilibration of the soil with 0.01N CaSO4 without 2,4,5‐T increased Kf by a factor of 2.6. All changes in Kf were statistically significant. Variations in Kf values are sufficiently great that one could classify the mobility of 2,4,5‐T in the Palouse soil as low or high.

Desorption under all experimental conditions examined resulted in apparent hysteresis. However, the observed hysteresis may have partially resulted from the use of the batch equilibration method to conduct the desorption studies. Each desorption equilibration step apparently altered the physical and/or chemical properties of the soil‐solution system in which the desorption occurred, compared with those in which the original pesticide‐soil‐solution adsorption equilibrium was evaluated.
Herbicide Runoff From Experimental Watersheds
Authors: Wu T. L. , Correll D. L. , Remenapp H. E. H.
Published: July 2010

Two commonly used herbicides in corn fields of the Rhode River Watershed were atrazine (2‐chloro‐4‐ethylamino‐6‐iso‐propylamino‐1,3,5‐triazine) and alachlor (2‐chloro‐2′,6′‐diethyl‐N‐methoxymethyl acetanilide). Although alachlor was applied in larger quantities, atrazine was detected more frequently in runoff waters and had greater concentrations than alachlor (0–40 µg/L vs. 0–6 µg/L). Atrazine was more persistent and more mobile in watershed soils. Linear regression analysis of herbicide loading rates and percentage agricultural land‐use did not give a direct relationship. Runoff waters from forest watersheds where herbicides were not directly applied, were contaminated with herbicides. During the 3‐y study period (1976–1978), a maximum of 10 µg/L of atrazine, and up to 0.5 µg/L alachlor were discharged in winter runoff waters from the eight experimental watersheds. In addition to quantity of herbicides directly applied to land surface, residual levels in runoff waters must be influenced by other important factors such as topography, location of croplands in relationship to drainage channel, etc. A major portion of atrazine was found in dissolved aqueous form in runoff‐water samples collected during storm events. Percolation in subsurface flow and dissolution in overland flow were believed to be important transport mechanisms.
The Agricultural Potential of Dredged Materials as Evaluated by Elemental Composition of Growing Plants
Authors: Combs S. M. , Dowdy R. H. , Gupta S. C. , Larson W. E. , Gast R. G.
Published: July 2010

The potential for using dredged materials (DM) as a plant growth medium and as an amendment for marginally productive agricultural soils was evaluated by studying the elemental composition of plants grown on DM and soil‐DM admixtures. Barley (Hordeum vulgare L.) and ryegrass (Lolium multiflorum Lam.) grown on selected DM produced dry matter nearly equal to that of plants grown on Minnesota agricultural soils in the greenhouse. Plant growth on some sediments was limited by suspected P and Mg deficiencies. Reduced, species‐dependent dry matter production was correlated with excessive tissue concentrations of Al, B, Cu, Mn, and/or Zn. Additions of fine‐textured DM to coarse‐textured, marginally productive soils resulted in increased dry matter production, while additions of coarse‐textured DM to fine‐textured soils reduced their yields. Barley was generally more susceptible to growth depressions than ryegrass.

Barley and ryegrass grown on some DM contained toxic levels of B (244 µg/g), Cu (39 µg/g), Mn (643 µg/g), and Zn (292 µg/g). Plant Zn was significantly correlated with sediment Zn concentrations, and was dependent upon pH and the Zn associated with extractable iron oxides. Barley generally accumulated more Cd than ryegrass.

Additions of fine‐textured DM to coarse‐textured, marginally productive soils resulted in species‐dependent, increased elemental accumulations in barley and ryegrass. Additions of coarse‐textured DM to corresponding fine‐textured soils did not affect plant compositions.
Viability of Rhizobium in Fertilizer Slurries Used for Hydroseeding
Authors: Brown Mark R. , Wolf Dale D. , Morse Ronald D. , Neal John L.
Published: July 2010

Drastically disturbed lands such as surface‐mined areas often require fertilizer, lime, mulch, and seed for adequate revegetation. Hydroseeding is the most common seeding method used in mountainous, uneven terrain. Where legumes are included as part of the seed mixture, inoculation with Rhizobium is recommended, since disturbed areas are likely to be devoid of desirable indigenous rhizobia. Hydroseeder slurries are sometimes found to be acidic because of the fertilizer components added. The influence of fertilizers on pH, and resultant Rhizobium viability in slurries was examined in order to establish recommendations for hydroseeder mixtures. Of the fertilizer components commonly used for hydroseeding, only those with phosphorus (P) were found to influence slurry pH. Addition of triple superphosphate (TSP) resulted in a pH of 2.9, as compared with diammonium phosphate (DAP), which had a pH value of 7.7. Significant loss of Rhizobium viability occurred at pH values of < 6.0. Pulverized agricultural lime (CaCO3) did not alter slurry pH; however, hydrated lime (Ca(OH)2), when added in sufficient amounts, increased the pH to levels favorable to the survival of added rhizobia inoculant. Based on the results of this study, a hydroseeder slurry should contain enough DAP in the fertilizer blend to have a pH of ≥ 6.0 (at least 40% of P from DAP) in order to ensure rhizobial survival of sufficient duration to allow effective inoculation of the legume seed. Different Rhizobium strains can possibly vary in tolerance to acidity; however, acidity can be easily corrected to avoid any possible problem.
Accumulation of Cadmium and Zinc in Barley Grown on Sludge‐Treated Soils: A Long‐Term Field Study
Authors: Chang A. C. , Page A. L. , Warneke J. E. , Resketo M. R. , Jones T. E.
Published: July 2010

A sludge land application experiment was initiated near Riverside, Calif. in 1975. Upon the incorporation of the annual sludge treatment, winter barley (Hordeum vulgare L.) was planted. The Cd and Zn contents of barley grown at the sludge application site were analyzed. Statistical testing indicated that the concentration of Cd and Zn in the barley increased significantly with the rates of sludge application. Although the Cd and Zn concentrations in the soil have risen rapidly with repeated sludge applications, there was little indication that the Cd and Zn contents of the barley increased with the increased deposition of Cd and Zn in the soil. By assuming the observed Cd and Zn contents of barley under a given sludge treatment follow a normal distribution, the probability of Cd and Zn in the harvested barley to exceed a given upper limit may be calculated. It shows that the probability for Cd and Zn contents to exceed the threshold increases with the rates of sludge application. For example, the probability for Cd in the barley grain to exceed 0.1 mg kg−1 increased from < 1% to almost 60% when the composted sludge application on Greenfield sandy loam (coarse‐loamy, mixed, thermic Typic Haloxeralf) increased from 0 to 90 Mg ha−1 y−1. Under the identical sludge treatment, the probability to exceed the limit is considerably lower in the heavier textured soil (Domino loam—fine‐loamy, mixed, thermic Xerollic Calciothid).
2,4‐D—Its Distribution and Effects in a Ryegrass Ecosystem
Authors: Gile Jay D.
Published: July 2010

The fate and effects of the 14C‐labeled butyl ester of 2,4‐D (2,4‐dichlorophenoxyacetic acid) applied as a foliar spray (1 kg ha−1) were examined in a simulated ryegrass (Lolium perenne) ecosystem. The ecosystem consisted of a sandy loam soil, annual ryegrass, numerous invertebrates, and a gray‐tailed vole (Microtus canicaudus) housed in a terrestrial microcosm chamber (TMC‐II). In addition to 2,4‐D distribution, the study was designed to evaluate the reproducibility of data derived from TMC‐II studies within and between experiments. One month after 2,4‐D application, all of the 14C materials detected in the soil were present as unextractable residues in the top 1 cm; plant material contained an average of 8.9 mg kg−1, identified primarily as 2,5‐dichloro‐4‐hydroxyphenoxyacetic acid. Residue levels in the animals ranged from 0.6 mg kg−1 for earthworms (Lumbricus spp.) to 5.3 mg kg−1 in pillbugs (Armandillarium spp.) of unidentified 14C residues. In excess of 90% of the material collected in the air stream was recovered within 24 h of application, which was identified as the butyl ester with no acid metabolites evident. The only effect observed in the ecosystem was a weight loss in the voles exposed to 2,4‐D, in comparison with the control.
The Effect of Mount St. Helens' Volcanic Ash on Plant Growth and Mineral Uptake
Authors: Cochran V. L. , Bezdicek D. F. , Elliott L. F. , Papendick R. I.
Published: July 2010

A greenhouse experiment was conducted to determine if unleached volcanic ash from the 18 May 1980 eruption of Mount St. Helens would affect plant growth and uptake of N, P, K, Zn, and Cd. The electrical conductivity of the ash was 5.0 dS m−1, and contained moderate amounts of available P, Ca, Mg, and SO4. Total Cd was 6 µg g−1, which is greater than that of most western soils. Swiss chard (Beta vulgaris cicla L.) and barley (Hordeum vulgare L.) were grown in Ritzville silt loam soil (mesic Calciorthidic Haploxerolls) amended with ash at rates of 0, 50, 100, 200, or 400 g kg−1, or with sand at the rate of 200 g kg−1. One‐half of all soils received wheat straw (Triticum aestivum L.) to increase microbial activity. No adverse effects on either swiss chard or barley were found with ash amendments, with or without wheat straw additions. The addition of ash increased concentrations of Zn in swiss chard, but barley Zn concentrations were unchanged by ash amendments. The Cd concentration was below detectable limits in barley for all treatments and was decreased by ash amendments in swiss chard, with or without incorporated wheat straw.
Microbial Respiration and Chemical Speciation in Metal‐Amended Soils
Authors: Lighthart Bruce , Baham John , Volk V. V.
Published: July 2010

Soil microbial respiration was measured on five soils after treatment with metal salt additions (0.0–50 mmol kg−1 metal to dry wt soil) to evaluate the effect of metal toxicity. After 45 d incubation at 20°C, most lower level metal treatments (0.05 and 0.5 mmol kg−1) had little effect on soil microbial respiration, whereas the higher levels (5 and 50 mmol kg−1) sharply inhibited respiration, suggesting a general threshold for metal toxicity between the 0.5 and 5 mmol kg−1 metal.

GEOCHEM, an equilibrium thermodynamic computer model, was used to simulate the chemical speciation of Cu and Cd in two soils. Values for the simulated concentration of the “free” Cd2+ species at which 5–10% inhibition of soil respiration occurred (10 µM) were comparable with those measured in pure bacterial culture fluids. Because of adsorption and complexation by the organic soil, more total Cd was required to achieve an equivalent Cd2+ concentration value in the simulated soil solution. The model of simulated Cd species distribution was supported by the fact that equal Cd amendments to both soils resulted in less growth inhibition in the organic soil. When Cd contamination of the two soils was near the toxic threshold level, relatively small increases in soil acidity could markedly increase Cd2+ concentration in the soil solution.

Simulated Cu species distribution for the organic soil correlated with inhibition of respiration. Dissolved Cu was predicted to inhibit microbial respiration when the free ion acidity reached a value of 0.01–0.1 µM in the soil solution.
Responses of Selected Plant Species to Elevated Carbon Dioxide in the Field
Authors: Rogers H. H. , Bingham G. E. , Cure J. D. , Smith J. M. , Surano K. A.
Published: July 2010

It has become of interest to study long‐term effects of CO2 concentration on plant growth, because intensive burning of fossil fuels and destruction of forests promise to continue the recent rise in atmospheric partial pressures of CO2 into the next century (Bolin, 1977; Stuiver, 1978). Effects of CO2 enrichment on growth of crop and forest species were therefore studied for the first time in the field in open top exposure chambers at daytime mean CO2 concentrations of 612, 936, 1292, and 1638 mg m−3, and in ambient control plots. Increased growth of plant parts of corn (Zea mays L. ‘Golden Bantam’), soybean [Glycine max L. (Merr.) ‘Ransom’], loblolly pine (Pinus taeda L.), and sweetgum (Liquidambar styraciflua L.) were recorded. Growth increases for soybean and sweetgum in elevated CO2 atmospheres were due to increases in leaf area and photosynthesis per unit leaf area, and decreases in conductance and, therefore, water use. For corn, however, photosynthesis was unaffected by CO2 enhancement, and growth stimulation appeared to be due to lowered conductance and increased water use efficiency alone.
Nutrient Cycling in an Agricultural Watershed: II. Streamflow and Artificial Drainage
Authors: Lowrance R. Richard , Todd Robert L. , Asmussen Loris E.
Published: July 2010

Streamflow is an important means of nutrient export off most watersheds. In agricultural areas, effluent from artificial drainage can be an important contribution to streamflow nutrient loads. The objective of this study was to examine seasonal variations of nutrients in streamflow and to quantify the effects of artificial drainage effluent on streamflow nutrients on an agricultural watershed. Concentrations and loads of NO3‐N, NH4‐N, organic N, dissolved molybdate‐reactive P, total P, Ca, Mg, K, Cl, and SO4‐S were measured in streamflow and artificial drainflow on a 1568‐ha agricultural watershed near Tifton, Ga. All 10 streamflow sampling sites had maximum NO3‐N and SO4‐S concentrations in winter and most reached minima during summer. Concentrations of NO3‐N, Ca, Mg, K, and Cl were generally much higher in drainage water than streamflow. Load of NO3‐N from drained row‐cropped fields was about 40.4 kg ha−1 y−1, 60 times the per‐hectare NO3‐N load from the mixed cover watershed. Loads of organic N, Ca, Mg, K, SO4‐S, and Cl from the mixed cover watershed were 2.8, 9.3, 4.5, 6.5, 17.0, and 30.0 kg ha−1 y−1, respectively. Loads (per hectare) of organic N were lower from the drained fields, but loads of Ca, Mg, K, SO4‐S, and Cl were lower from the mixed cover watershed. In‐stream and riparian zone processes apparently converted inorganic N to organic forms and removed N through denitrification. Annual streamflow N load was about 29% of the precipitation input of 12.2 kg ha−1 y−1. Sediment‐associated N and P loads in streamflow were 0.35 and 0.09 kg ha−1 y−1, respectively, accounting for 9.0 and 8.5% of total N and P, respectively. The two highest flow events for the year carried 19% of the total annual flow and 19% of the annual sediment load, but had 30 and 27% of the total annual sediment N and P loads, respectively. This enrichment of sediment‐associated N and P indicates that part of this sediment load moved directly from upland areas.
Effects of Varying Salt Levels in Liquid Swine Manure on Soil Composition and Corn Yield
Authors: Sutton A. L. , Nelson D. W. , Mayrose V. B. , Nye J. C. , Kelly D. T.
Published: July 2010

A 4‐y field experiment was conducted to determine the effects of liquid swine manure application to silt loam and silly clay loam soils cropped to corn (Zea mays L.). Manure from growing‐finishing pigs fed 16% crude protein diets with either 0.2 or 0.5% supplemental salt was collected and stored in oxidation ditches or anaerobic pits. Swine manure (2.0–3.3% dry matter) from the four dietary salt by waste treatment combinations was surface‐applied annually to Fox and Raub silt loam and Chalmers silty clay loam soils at rates of 90, 180, and 270 t/ha for 3 y. No manure was applied the fourth year to determine residual nutrient effects. Check and inorganic fertilizer treatments were also studied.

Increasing dietary salt levels increased Na levels in manure and Na loading of the soil. The maximum rate of Na loading was 123 kg/ha/y from manure from pigs fed the 0.5% dietary salt level. Soil exchangeable Na, exchangeable K, available P and NO3−‐N concentrations increased each year of manure application, but there was a depletion after the residual year for all except available P. High manure applications did not adversely affect corn yields; however, applications above the 90‐t rate exceeded crop nutrient needs for all soil conditions. The effects of aerobic vs. anaerobic manure handling systems on corn yields, plant composition and soil composition were inconsistent.

Corn leaf analyses for N tended to reflect N application rates, but other leaf nutrient concentrations did not consistently reflect nutrient loadings from manure. Application rates of liquid manure used in this study did not lead to soil contamination nor corn plant phytotoxicity problems.
Accumulation of Heavy Metals in Sewage Sludge‐Treated Soils
Authors: Chang A. C. , Warneke J. E. , Page A. L. , Lund L. J.
Published: July 2010

The accumulation of Cd, Cr, Cu, Ni, Pb, and Zn in sewage sludge‐treated soils was studied after 6 y of continued annual sludge application at a cropland disposal site. Soil samples were taken at 15‐cm depth increments from Greenfield sandy loam (coarse‐loamy, mixed, thermic, Typic Haploxeralf) and Domino loam (fine‐loamy, mixed, thermic Xerollic Calciothid) that received 0 (control), 22.5, 45, and 90 Mg ha−1 y−1 of composted sludges or 0 (control), 3.75, 7.5, and 15 cm y−1 of liquid sudges since 1976. Samples were also obtained from areas where liquid sludge treatment was terminated after 1978. Heavy metals in soils were extracted by 4M HNO3 and analyzed by atomic absorption spectroscopy. Over 90% of the deposited heavy metals were found in the 0‐ to 15‐cm soil depth where sludges were incorporated; no statistically significant increase in heavy metal contents of the soil was detected below the surface 30 cm of the soil profile. Although crop absorption of heavy metals has increased with the sludge application rates, the total uptake amounted to < 1% of the metal introduced through sludge application. Through a material balance calculation, it was found that recovered heavy metals were low relative to amounts added due to incomplete extraction of metals from soils by 4M HNO3 and changes in soil bulk density.
Cyanazine Losses in Runoff from No‐Tillage Corn in “Living” and Dead Mulches vs. Unmulched, Conventional Tillage
Authors: Hall J. K. , Hartwig N. L. , Hoffman L. D.
Published: July 2010

Losses of cyanazine (2‐[[4‐chloro‐6‐(ethylamino)‐s‐triazin‐2‐yl]amino]‐2‐methylpropionitrile) in runoff from untilled soil planted to corn (Zea mays L.) were compared with losses from conventionally planted corn on a 14% slope in the growing seasons of 1977 through 1979. The no‐tillage systems consisted of corn planted into corn stover residue and into “living mulches” of birdsfoot trefoil (Lotus corniculatus) and crownvetch (Coronilla varia L.). The no‐tillage systems reduced runoff, erosion, and herbicide movement. For example, runoff from conventional tillage ranged from 5.5 to 22% of the runoff‐producing rainfall. Soil loss from the same system ranged from 4.4 to 32.2 Mg/ha. On the other hand, runoff from the no‐tillage systems ranged from 0.07 to 2.5% of the runoff‐producing rainfall, while soil losses ranged from 0 to 1.1 Mg/ha.

Transport of cyanazine in water runoff and entrained sediment from tilled areas totaled 257.0, 16.0, and 32.7 g/ha for the respective growing seasons, which represented 5.71, 0.73, and 1.48% of the amount applied yearly [4.5 kg active ingredient (ai)/ha—1977; 2.2 kg ai/ha—1978, 1979]. In the same years, cyanazine losses from no‐tillage areas were 6.5–33.7 g/ha, 0.1–1.8 g/ha, and 1.6–3.3 g/ha at similarly applied rates. Collectively, these represented losses ranging from < 0.01 to 0.75% of sprayed levels. Using conventional tillage as a reference treatment, untilled surfaces reduced runoff from 86.3 to 98.7%, soil losses from 96.7 to 100%, and cyanazine losses from 84.9 to 99.4% over the three growing seasons. In general, the “living mulch” surfaces were more effective in retarding erosion than the corn stover residue surfaces. Corn grain yields were not significantly reduced by “living mulches” when adequate legume suppression was obtained with herbicide treatments.
Persistence and Degradation of Mutagens in Sludge‐Amended Soil
Authors: Angle J. S. , Baudler D. M.
Published: July 2010

The presence of toxic organics and mutagenic activity in sewage sludge presents a potential problem when contaminated sludge is applied to soil. Sewage sludges from Washington, D.C. were assayed for mutagenic activity using the Ames Assay. Raw cake, digested cake, biologically thickened sludge, and composted sludges were extracted with water and ethylene dichloride. No mutagenic activity was detected in any of the water extracts. Only the ethylene dichloride extract of the biologically thickened sludge contained significant quantities of mutagens.

Biologically thickened sludge was subsequently added to a Chester loam soil at a rate of 112 Mg ha−1. The soils were incubated for 8 weeks. Periodically, the sludge‐amended soils were extracted and the mutagenic activity of the extract determined as before. Unamended control soils were also extracted as a control.

The mutagenicity of the sludge‐amended soil was found to increase during the initial 7 d of the study. Seven days after the initiation of the study, the number of revertants (Salmonella typhimurium strain TA‐98) induced by the extract from the sludge‐amended soil was 150 per plate. The control soil extract exhibited 95 revertants per plate. After 7 d, the quantity of mutagens extracted from the sludge‐amended soil rapidly decreased. This was probably due to the rapid degradation of these compounds in soil.
A Predictive Model for the Accumulation of Cadmium by Container‐Grown Plants
Authors: Browne C. L. , Wong Y.‐M. , Buhler D. R.
Published: July 2010

Research into the dietary availability of Cd, a toxic heavy metal, called for prediction of Cd accumulation by edible crop species to be grown to maturity under greenhouse conditions. Examination of the literature revealed that Cd accumulation in plants grown under greenhouse and oxic conditions could be generally described, with high correlation, by the equation:
urn:x-wiley:15391663:jeq2jeq198400472425001300020002x:equation:jeq2jeq198400472425001300020002x-math-0001 where P is plant Cd (µg Cd/g dry wt), CdDTPA is the DTPA (diethylenetriaminepentaacetic acid) extract estimate of available soil Cd (µg Cd/g soil), and α and β are linear regression coefficients. Published data were fitted to the above equation to determine whether the model coefficients exhibited consistent relationships that would predictably account for the potential effect of soil type, species, and experimental conditions on the accumulation of Cd by plants. For a given experimental situation, β was found to be principally a function of soil pH and cation exchange capacity (CEC), and a single mean value was deemed appropriate for all species. The coefficient α was mainly a characteristic of plant species, and the relative magnitude of the difference among species in the value of α tended to remain constant for differing experimental conditions. Assuming that such a relationship was common to greenhouse crops, estimates of α for several species to be grown under our conditions were derived from the literature. This was accomplished by comparison with values of µ for test crops of spinach (Spinacia oleracea L.) and lettuce (Lactuca sativa L.) grown under our conditions. Substitution of estimated values of α and β into the above equation permitted the successful prediction of soil Cd additions (0.5–15 µg Cd/g) necessary to achieve a specified level Cd in the range of crop species subsequently grown to maturity.
The Relationship Between Adsorption of Trace Metals, Organic Matter, and pH in Temperate Soils
Authors: Gerritse R. G. , van Driel W.
Published: July 2010

Distribution constants for Cd and Pb were measured for 33 temperate soils. The distribution constants were related to soil organic matter and pH at three different ionic strengths of soil extractants. The soil extractants consisted of solutions of CaCl2, NaCl, and KCl and were taken to be representative of the composition of the soil solution phases. For each ionic strength a significant log‐log correlation was found between the distribution constants, related to organic matter content of the soil and the hydrogen ion concentrations of the soil extracts. Exchangeable or mobile fractions of Cd and Pb in the soil were calculated from the product of distribution constant and concentration in a soil extract. With the aid of adsorption data of previous work with other soils, assuming a similar relationship as found for Cd and Pb, comparable results were obtained for Cu and Zn. Exchangeable fractions were found to lie in a range of about 1 to 5% of total metal in the soils for Pb and about 10 to 50% for Cd, Zn, and Cu.
Responses of Soil Biota to Organic Amendments in Stripmine Spoils in Northwestern New Mexico
Authors: Elkins Ned Z. , Parker Lawrence W. , Aldon Earl , Whitford W. G.
Published: July 2010

We examined the effects of organic amendments and topsoiling on the soil biota and decomposition in order to evaluate the relative efficacy of the amendments in restarting soil processes. We studied decomposition of barley straw (Hordeum vulgare) and populations of soil biota on strip coal‐mine spoils in northwestern New Mexico. The spoils had been amended with straw mulch, bark, topsoil, or no organic additives. Decomposition rates were highest in the unmined area and the bark, amended spoils (K = 0.64 yr−1) (K = first‐order rate constant), and lowest on the topsoil amendment and unamended spoil (K = 0.34 yr−1). Few differences were observed in the populations of soil microflora. Where differences were observed, the bark‐amended spoils had the highest populations and biomass. Soil microflora activity, as indicated by decomposition rates, was enhanced by bark amendment. Soil microfaunal populations were highest on the bark‐amended spoils and unmined soil. Important soil mites (soil Acari), the oribatids, were found only in the bark‐amended spoils and the unmined soils. These studies suggest that addition of selected organic amendments (bark) to mine spoils may be as effective in developing a soil as the more expensive topsoil/mulch procedures currently used in reclamation procedures.
Potential Aquifer Pollution from Nitrate Leaching Following the Plowing of Temporary Grassland
Authors: Cameron K. C. , Wild A.
Published: July 2010

An investigation of the amounts and concentrations of nitrate released following the plowing of temporary grassland confirmed that, potentially at least, this practice forms a major source of NO3‐N pollution of aquifers. Direct measurements of changes in profile NO3‐N distributions at two sites show that a total of up to about 100 kg N ha−1 was leached over two winters after fall mineralization following plowing. Solution nitrate concentrations were in excess of the World Health Organization limits for drinking water. The amount of N mineralized was related to the total soil N. The average rate of leaching through the Chalk soils studied in southern England was about 1 m/yr.
Nutrient Trapping by Sediment Deposition in a Seasonally Flooded Lakeside Wetland
Authors: Johnston C. A. , Bubenzer G. D. , Lee G. B. , Madison F. W. , Mc Henry J. R.
Published: July 2010

Sediment and nutrient retention was studied in a seasonally flooded lakeside wetland as a natural mechanism for preventing water quality deterioration. Both wetland and upland soils in the watershed had comparable concentrations of inorganic P on a per‐volume basis, while NH4+‐N and organic forms of N and P were much higher in the wetland soils. Nitrate concentrations expressed in a per‐volume basis were lower in the wetland soils than in the upland soils.

The distribution of sediment and nutrients in the wetland was correlated with distance from a small stream flowing through the wetland. Deposition patterns were affected by recent stream channel migrations.

The accumulation of nutrients and sediment delivered from the upland to wetland soils was estimated in two ways: (i) by calculating the volume of alluvium deposited in low natural levees adjacent to the stream; and (ii) by estimating nutrient and ash enrichment of histic surface soils farther away from the stream. Although the levees constituted only about 20% of the wetland surface area, they accounted for 81% of the sediment, 84% of the N, and 67% of the P retained by the wetland.

The depth of Cs‐137 in the soil was used to estimate net sedimentation rates. Average annual accumulations over the wetland as a whole were: 2.0 kg sediment m−2 yr−1, 2.6 g P m−2 yr−1, and 12.8 N g m−2 yr−1. Since these values exceed those published for average annual storage by wetland plants, soil mechanisms are more important than vegetative uptake for long‐term nutrient and sediment retention in the White Clay Lake wetland.
Prediction of Phosphate Movement Through Some Selected Soils
Authors: Stuanes Arne O. , Enfield Carl G.
Published: July 2010

The P sorption capacity of soils must be evaluated at land application wastewater sites when water quality criteria control the design of the treatment system. The soil's capacity to react with P is often underestimated when equilibrium isotherms are used to describe P sorption. An analytical one‐dimensional convective dispersive solute transport model, assuming linear sorption and first‐order irreversible precipitation, was evaluated to describe the movement of P in small laboratory columns. The model was calibrated to experimental data using nonlinear least squares analysis. The length of the column did not make a significant difference in the model coefficients. This finding suggests that the approximation of a linear sorption isotherm with first‐order irreversible precipitation is adequate for making environmental assessments at land‐treatment systems. Application of the model to the design of a land‐treatment system would permit approximating a system life considering wastewater application rate, concentration of P in the applied water, and travel distance through the soil profile prior to discharge. Experimental data fit to a Langmuir equation using the same soils were found to seriously underestimate the capacity of soil to react with P. The same data fit to a Freundlich or other equilibrium isotherm would yield similar results. It was concluded that use of equilibrium isotherms without considering the kinetics of the reactions will lead to overly conservative designs of land application of wastewater treatment systems.
Elements Associated with the Cadmium Phase in a Harbor Sediment as Determined with the Electron Beam Microprobe
Authors: Lee F. Y. , Kittrick J. A.
Published: July 2010

A heavy metal‐contaminated harbor sediment was examined with the electron beam microprobe in order to obtain specific information with regard to the elements associated with the Cd phase(s). Approximately 4.4 × 104 particles were scanned in order to locate 18 that produced > 100 counts/s Cd Kα X‐radiation. Of these Cd‐rich particles, 72% were < 10 µm in diameter. For these particles, Cd was most frequently associated with S (in ca. 89% of the particles, presumably as S2−), rather than with the carbonate indicated by a chemical extraction method on the whole soil. Zinc was also significantly associated with Cd (in ca. 72% of the particles). Cadmium appeared to be precipitated with the associated elements rather than being adsorbed on the surfaces of the selected 18 particles. The formation of Cd sulfides in the sediment can be predicted from thermodynamic calculations, combined with a few reasonable assumptions.
Organic Pollutants in Leachates from Landfill Sites
Authors: Sawhney B. L. , Kozloski R. P.
Published: July 2010

Growing concern for groundwater pollution with potentially hazardous organic chemicals from waste disposal sites prompted this investigation of determining organic pollutants in leachates from a number of municipal landfill sites. Identification of the various compounds was attained using multicolumn GC and GC/MS (gas chromatography/mass spectrometry) techniques. Volatile compounds were concentrated using purge and trap technique and nonvolatile compounds were fractionated into the alkali and acid extracts. Quantitative determinations were made by comparing heights or areas of the GC peaks obtained from the test samples to the corresponding peaks from the standard compounds. Different volatile compounds identified in leachates from landfill sites varied over a wide concentration range. Determinations of volatile compounds in leachates from the Southington, CT landfill site showed large concentrations of some common industrial solvents such as acetone and methyl ethyl ketone. Presence of as high as 4 mg/L of phenols which are readily sorbed and transformed by soils and clays under laboratory conditions suggest that anaerobic landfill conditions may facilitate the movement of phenols and other organic compounds.
Uptake by Plants and Migration of Uranium and Chromium in Field Lysimeters
Authors: Sheppard Marsha I. , Sheppard S. C. , Thibault D. H.
Published: July 2010

Plant growth, plant uptake, and the redistribution in soil of U and Cr were studied in field lysimeters. The objective of the experiment was to characterize the plant uptake and migration in the soil of U and Cr when placed at different depths in the unsaturated soil zone within the influence of a water table. Lysimeters with and without vegetation were studied and two soils, and two plant species were investigated.

Total uptake of Cr by the plants was directly proportional to Cr concentration in the soil, over eight orders of magnitude. Thus, independent of the amount of Cr applied, the plant took up a similar fraction, about 0.007. Chromium placement depth in the soil did not influence Cr uptake by the plants although the Cr was relatively immobile in both soils.

Plant uptake of U was independent of plant species and U placement depth for loam soil, but highly dependent on placement depth in sandy soil. In the latter, much more U was taken up by the plants when it ws placed near the soil surface, implying that uptake was dependent upon root activity. Migration of U from the contaminant band was substantial only in the sandy soil.
Molybdenum Enrichment of Plants Grown on Fly Ash‐Treated Soils
Authors: Elseewi A. A. , Page A. L.
Published: July 2010

Alfalfa, bermudagrass, white clover, barley, and Swiss chard (Medicago sativa L., Cynodon dactylon L., Trifolium repens L., Hordeum vulgare L., and Beta vulgaris L., respectively) were grown on calcareous and acid soils treated with fly ash at rates ranging up to 80 g kg−1. The objectives were to investigate the availability of Mo to crops in relation to rate of fly ash application, type of recipient soil, and time of harvest. Application of fly ash to soil resulted in marked enrichment in plant Mo, especially at rates ≥ 40 g kg−1. Except for white clover, Mo concentrations in plants grown on the calcareous soil were greater than those in plants grown on the acid soil. Comparison between Mo concentration in early‐ and late‐season clippings of alfalfa and white clover and in plants grown sequentially indicated the presence of a relatively long‐term supply of Mo in fly ash. It is concluded that in situations where soils are deficient in Mo, plants may benefit from small applications of fly ash to soils, but Mo concentrations in plants grown on fly ash‐treated soils should always be carefully monitored.
Power Plant Influences on Bulk Precipitation, Throughfall, and Stemflow Nutrient Inputs
Authors: Kelly J. M.
Published: July 2010

Inputs of SO42−, total N, PO43−, K, Ca, and Mg via bulk precipitation, throughfall, and stemflow have been investigated over a 3‐yr period at two forest study sites on the Cumberland Plateau of Tennessee. The Cross Creek Watershed located 19 km from the Widows Creek coal‐fired power plant was used to represent inputs to a forest site in the immediate vicinity of a large emissions source. The Camp Branch Watershed having similar forest cover and soil types, but located in an area 99 and 76 km from the nearest major point sources, was used to represent inputs as a function of regional conditions. Location exhibited its greatest influence on stemflow inputs, with only PO43− and K failing to exhibit a statistically significant (P = 0.05) increase in stemflow input at Cross Creek relative to Camp Branch. Although throughfall SO42−, K, Ca, and Mg input values were higher at Cross Creek, they were not significantly higher than the Camp Branch values. Nitrogen and phosphate throughfall input values were lower at Cross Creek than Camp Branch, but again lacked statistical significance. Nitrogen and phosphate in bulk precipitation were significantly elevated at Cross Creek while other elements and compounds did not respond to location. Based on this evaluation most atmospheric contributions to bulk precipitation, throughfall, and stemflow elemental inputs appear to be of regional rather than local origin.
Mined Land Reclamation Using Polluted Urban Navigable Waterway Sediments: I. Trace Metals
Authors: Van Luik A.
Published: July 2010

As part of a study assessing the suitability of sediments from the Calumet‐Sag Channel, Illinois (Cal‐Sag), for use as a mined land reclamation medium, the concentrations of 11 trace metals were determined in 34 sediment samples representing 10 cores. The cores were taken at 2.4‐km intervals along the length of the Cal‐Sag using a gravity corer. The cores (107 to 173 cm in length) were divided into sections representing approximately 30 to 50 cm of core depth each. Each of these sections was sampled by compositing a sample from along its length. Silt and clay content were determined in addition to the concentrations of the 11 trace metals. Trends in the metal concentration data suggested that As and Hg had a different source and/or history in the Cal‐Sag sediments than Ba, Cd, Cr, Cu, Pb, and Zn. Nickel, selenium, and silver levels were determined for 10 of the samples. Implications of trace metal levels in terms of using Cal‐Sag sediments as a plant‐growth medium in mined land reclamation are discussed. Zinc levels may preclude use of Cal‐Sag sediments for the production of some specific Zn‐sensitive agronomic crops and may require longterm monitoring after placement in productive use to allow management of potential Zn phytotoxicity. Mean total trace metal concentration values for this Cal‐Sag sediment sampling were (mg/kg): As, 19; Ba, 320; Cd, 9.4; Cr, 110; Cu, 120; Pb, 510; Hg, < 0.42; Ni, 38; Se, 0.10; Ag, 4.9; and Zn, 2580.
Mined Land Reclamation Using Polluted Urban Navigable Waterway Sediments: II. Organics
Authors: Van Luik A.
Published: July 2010

Maintenance dredging potentially produces an estimated 15 000 m3 of sedimentary material from the Calumet‐Sag Channel (Cal‐Sag) annually. To determine the suitability of this dredged material for use in the reclamation of abandoned mined lands, 10 sediment samples were taken at 2.4‐km intervals along the length of the Cal‐Sag using a gravity corer. Sediment cores (107 to 173 cm in length) were subdivided to represent 40‐ to 50‐cm depth increments, and composite samples were taken along the length of each subsample. Organic pollutant concentrations as well as silt and clay contents were determined. No significant correlations existed between each organic pollutant concentration and sediment sample depths, locations, or sediment silt or clay content. This result suggested that the mean and the mean plus twice the standard deviation offered good approximations of the expected mean value and the expected (95%) maximum value for these pollutants in Cal‐Sag dredged material (volatile solids: 9.85 and 13.1 mg/kg; oil and grease: 11.9 and 22.7 g/kg; total phenols: < 2.4 and < 4.8 mg/kg; and total polychlorinated biphenyls (PCB's): 7.0 and 17 mg/kg). Polycyclic aromatic hydrocarbon (PAH) levels were determined for nine selected Cal‐Sag sediment samples. Measured parent PAH compound levels (46 compounds) exceeded 80 mg/kg in only one sample. Alkyl‐substituted PAH compound concentrations were measured for three parent compounds in three sediment samples and found to be highly variable in concentration (∼ 1 – ∼ 500 mg/kg).