bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of Experimental Variables on 2,4,5‐T Adsorption‐Desorption in Soil
Authors: Koskinen W. C. , Cheng H. H. 
Published: July 2010

AbstractThe 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

AbstractTwo 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

AbstractThe 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

AbstractDrastically 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

AbstractA 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

AbstractThe 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

AbstractA 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

AbstractSoil 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

AbstractIt 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

AbstractStreamflow 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

AbstractA 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

AbstractThe 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

AbstractLosses 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

AbstractThe 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.