bluuebunny/crossref_metadata_2025 huggingface dataset:
Timing of Phosphorus Fertilizer Application within an Irrigation Cycle for Perennial Pasture
Authors: Bush Belinda J. , Austin Nicholas R.
Published: June 2010

Irrigated pastures are significant contributors of phosphorus (P) to inland watercourses, with much of the P coming from applied fertilizer. It was hypothesized that the timing of P fertilizer application relative to irrigation regulates P concentrations in runoff and infiltrating water. To test this hypothesis, a two‐by‐two factorial experiment was conducted on twelve 8‐ × 30‐m border‐irrigated bays growing perennial pasture. Phosphorus fertilizer in the form of single superphosphate (44 kg P ha−1) was surface‐broadcast onto the bays when the nominal change in soil water deficit reached 0 or 50 mm (U.S. Class A pan evaporation minus rainfall). Following fertilizer application, the bays were again irrigated when the nominal soil water deficit between fertilizing and the subsequent irrigation reached either 0 or 50 mm. The volume of water applied, runoff volume, and changes in soil water content were recorded for the three irrigations following fertilizer application. Total phosphorus (TP) and filtrable reactive phosphorus (FRP, <0.45 μm) concentrations in runoff and at depths of 0.1, 0.3, and 0.6 m in the soil were also measured. Soil water content at fertilizer application had less effect on P concentrations in runoff and soil water than the additional time between fertilizing and irrigating. By allowing a deficit of 50 mm between fertilizer application and irrigation, the average concentration of P in runoff and moving below a soil depth of 0.1 m was approximately halved. To maximize fertilizer use efficiency and minimize environmental effects, a delay should occur between applying P fertilizer and irrigating perennial pasture.
Effects of Alum and Aluminum Chloride on Phosphorus Runoff from Swine Manure
Authors: Smith D.R. , Moore P.A. , Griffis C.L. , Daniel T.C. , Edwards D.R. , Boothe D.L.
Published: June 2010

Phosphorus (P) runoff from fields fertilized with swine (Sus scrofa domesticus) manure may contribute to eutrophication. The objective of this study was to evaluate the effect of aluminum sulfate (alum) and aluminum chloride applications to swine manure on P runoff from small plots cropped to tall fescue (Festuca arundinacea Shreb.). There were six treatments in this study: (i) unfertilized control plots, (ii) untreated manure, (iii) manure with alum at 215 mg Al L−1, (iv) manure with aluminum chloride at 215 mg Al L−1, (v) manure with alum at 430 mg Al L−1, and (vi) manure with aluminum chloride at 430 mg Al L−1 Manure application rates were equivalent to approximately 125 kg N ha−1 Alum and aluminum chloride additions lowered soluble reactive phosphorus (SRP) levels from about 130 mg P L−1 to approximately 30 mg P L−1 at low rates. At high rates, SRP levels in swine manure were around 1 mg P L−1 Soluble reactive P concentrations in runoff were 5.50, 3.66, 3.00, 0.87, 0.87, and 0.55 mg P L−1, for normal manure, low alum, low aluminum chloride, high alum, high aluminum chloride, and unfertilized control plots, respectively. Hence, high alum and aluminum chloride reduced SRP concentrations in runoff by 84% and were not statistically different from SRP concentrations in runoff from unfertilized control plots. These data indicate that treating swine manure with alum or aluminum chloride could result in significant reductions in nonpoint‐source P runoff.
Aerosol Chemical and Optical Properties during the Mt. Zirkel Visibility Study
Authors: Watson John G. , Chow Judith C. , Lowenthal Douglas H. , Cahill Catherine F. , Blumenthal Donald L. , Richards L.Willard , Jorge Helena González
Published: June 2010

Aerosol chemical and optical properties were measured near the Mt. Zirkel Wilderness Area in northwestern Colorado. Six‐hour PM2.5 (particles with aerodynamic diameters less than 2.5 μm) mass concentrations and PM2.5 dry particle light scattering at 550 nm averaged 4.6 μg m−3 and 8.6 Mm−1, respectively. Sulfates, organic carbon, and geological material were the principle components of particle mass and light scattering. Hygroscopic growth was consistent with that expected for ammonium sulfate aerosols. Size distributions derived from three‐wavelength (i.e., 450, 550, and 700 nm) nephelometer data were similar to those measured in other remote areas of the western USA. Quasi‐dry chemical light scattering efficiencies derived using Mie theory were 3.6 m2 g−1 for organic carbon, 2.5 m2 g−1 for sulfates (ammonium sulfate and ammonium bisulfate), 2.6 m2 g−1 for ammonium nitrate, and 1.76 m2 g−1 for geological material. These values are lower than but consistent with previously reported results. Realistic efficiencies could not be derived using the multiple linear regression (MLR) approach.
Chemical Immobilization of Lead, Zinc, and Cadmium in Smelter‐Contaminated Soils Using Biosolids and Rock Phosphate
Authors: Basta N.T. , Gradwohl R. , Snethen K.L. , Schroder J.L.
Published: June 2010

Chemical immobilization, an in situ remediation method where inexpensive chemicals are used to reduce contaminant solubility in contaminated soil, has gained attention. We investigated the effectiveness of lime‐stabilized biosolid (LSB), N‐Viro Soil (NV), rock phosphate (RP), and anaerobic biosolid (AB) to reduce extractability and plant and gastrointestinal (GI) bioavailability in three Cd‐, Pb‐, and Zn‐contaminated soils from smelter sites. Treated (100 g kg−1 soil) and control soils were incubated at 27°C and −0.033 MPa (−0.33 bar) water content for 90 d. The effect of soil treatment on metal extractability was evaluated by sequential extraction, on phytoavailability by a lettuce bioassay (Lactuca sativa L.), on human GI availability of Pb from soil ingestion by the Physiologically Based Extraction Test. The largest reductions in metal extractability and phytoavailability were from alkaline organic treatments (LSB and NV). Phytotoxic Zn [1188 mg Zn kg−1 extracted with 0.5 M Ca(NO3)2] in Blackwell soil (disturbed soil) was reduced by LSB, NV, and RP to 166, 25, and 784 mg Zn kg−1, respectively. Rock phosphate was the only treatment that reduced GI‐available Pb in both gastric and intestinal solutions, 23 and 92%, respectively. Alkaline organic treatments (LSB, NV) decreases Cd transmission through the food chain pathway, whereas rock phosphate decreases risk from exposure to Pb via the soil ingestion pathway. Alkaline organic treatments can reduce human exposure to Cd and Pb by reducing Zn phytotoxicity and revegetation of contaminated sites.
Sources of Salinity Near a Coal Mine Spoil Pile, North‐Central Colorado
Authors: Zielinski Robert A. , Otton James K. , Johnson Craig A.
Published: June 2010

A small (1 km2) salt‐affected stream drainage on the High Plains north of Denver, Colorado was sampled to determine the near‐surface dispersion of soluble salts and metals from low‐sulfur coal mining waste (spoil). Surface waters collected along the 0.8‐km stream reach, and aqueous leachates of spoil and naturally saline local soil, were analyzed for chemical constituents and sulfur isotopes. In this semiarid setting with abundant carbonate‐bearing surficial sediments, the limited, mildly acidic drainage from the spoil pile is quickly neutralized, restricting the mobility of many elements. However, some spoil‐derived constituents were clearly traceable within the upper 0.4 km of the stream reach. Spoil leachates and surface water near the spoil pile have distinctive compositions of major anions and cations, and elevated levels of dissolved nitrate compared with downstream waters. Spoil‐derived sulfate was traceable because it has generally positive values of δ34S that contrasted with generally negative values of δ34S in soil leachates and evaporite salts from the surrounding area. Spatial–chemical sampling of surface water showed an abrupt increase in dissolved U, Se, B, Li, and Mn in the lower 0.4 km of the stream reach where shallow ground water from surrounding irrigated fields contributed to surface flow. The downstream evolution of surface water chemistry and sulfur isotopic composition is consistent with mixing between spoil‐affected upstream water and irrigation‐return water. The methods described should be applicable at other sites in similar settings where the environmental effect of low‐sulfur coal mining waste must be assessed and where access to samples of shallow ground water is limited.
Organochlorine Pollutants in Remote Mountain Lake Waters
Authors: Vilanova Rosa , Fernández Pilar , Martínez Carolina , Grimalt Joan O.
Published: June 2010

Hexachlorocyclohexanes (HCHs; α‐ and γ‐isomers), endosulfans (α‐ and β‐isomers and the sulfate residue), hexachlorobenzene (HCB), dichlorodiphenyltrichloroethane (DDTs), and polychlorobiphenyls (PCBs) were measured in waters from three European remote mountain lakes situated in the Alps, Pyrenees, and Caledonian mountains. Sampling encompassed both ice‐free and ice‐covered periods at different water column depths. High HCH concentrations were found in all lakes, those in the Alps and Pyrenees (990–2900 pg/L) being among the highest recorded in continental waters. Endosulfans and endosulfan sulfate (120–1150 pg/L) were the second major group of organochlorine contaminants, showing a remarkable stability upon atmospheric long‐range transport. The concentrations of HCB, DDTs, and PCB (4–8, 0.6–16, and 26–110 pg/L, respectively) were low in comparison with other continental waters. Hexachlorocyclohexanes, endosulfans, and HCB were essentially found in the dissolved phase. Phase partitioning of the more hydrophobic compounds exhibited a dependence on temperature and water‐suspended particles. Comparison between different sampling seasons and water depths indicated a remarkable concentration uniformity within lake, but major interlake differences. Normalization to turnover rates showed higher interlake similarity. Preferential accumulation of the less volatile compounds in the Alp lake and significant increase of baseline contributions of organochlorine compounds and residues in the Caledonian lake are also evidenced from these turnover rates.
Forest Fertilization with Wood Ash: Effect on the Distribution and Storage of Polycyclic Aromatic Hydrocarbons (PAHs) and Polychlorinated Biphenyls (PCBs)
Authors: Bundt Maya , Krauss Martin , Blaser Peter , Wilcke Wolfgang
Published: June 2010

Before wood ash can be safely used as a fertilizer in forests, possible negative effects such as input of organic contaminants or remobilization of contaminants already stored in the soil must be investigated. The objective of this study was to examine the effects of wood ash application on concentrations, storage, and distribution of polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) in a Swiss forest soil. In May 1998, we added 8 Mg wood ash ha−1 to a forest soil. We determined 20 PAHs and 14 PCBs in the organic layer, in the bulk mineral soil, and in soil material taken from preferential flow paths and from the matrix before and after the wood ash application. In the control plots, the concentrations of PAHs in the organic layer indicated moderate pollution (sum of 20 PAHs: 0.8–1.6 mg kg−1), but sum of PCB concentrations was high (21–48 μg kg−1). The wood ash had high concentrations of PAHs (sum of 20 PAHs: 16.8 mg kg−1), but low concentrations of PCBs (sum of 14 PCBs: 3.4 μg kg−1). The wood ash application increased the PAH concentrations in the organic horizons up to sixfold. In contrast, PCB concentrations did not change in the Oa horizon and decreased up to one third in the Oi and Oe horizons. The decrease was probably caused by the mobilization of stored PCBs because of the high pH of the wood ash. This probably results in a higher mobility of dissolved organic matter, acting as PCB carrier. In the mineral soil, the preferential flow paths of the A horizon contained more PAHs and PCBs (+20 ± 15% and +43 ± 60%, respectively) than the matrix. This was particularly true for higher molecular weight compounds (molecular weight > 200 g mol−1). Below 50 cm depth, concentrations of PAHs and PCBs were smaller in the preferential flow paths, suggesting that in deeper depths, processes acting as sinks dominated over inputs in the preferential flow paths.
Nitrate Loss in Subsurface Drainage as Affected by Nitrogen Fertilizer Rate
Authors: Jaynes D.B. , Colvin T.S. , Karlen D.L. , Cambardella C.A. , Meek D.W.
Published: June 2010

The relationships between N fertilizer rate, yield, and NO3leaching need to be quantified to develop soil and crop management practices that are economically and environmentally sustainable. From 1996 through 1999, we measured yield and NO3loss from a subsurface drained field in central Iowa at three N fertilizer rates: a low (L) rate of 67 kg ha−1in 1996 and 57 kg ha−1in 1998, a medium (M) rate of 135 kg ha−1in 1996 and 114 kg ha−1in 1998, and a high (H) rate of 202 kg ha−1in 1996 and 172 kg ha−1in 1998. Corn (Zea maysL.) and soybean [Glycine max(L.) Merr.] were grown in rotation with N fertilizer applied in the spring to corn only. For the L treatment, NO3concentrations in the drainage water exceeded the 10 mg N L−1maximum contaminant level (MCL) established by the USEPA for drinking water only during the years that corn was grown. For the M and H treatments, NO3concentrations exceeded the MCL in all years, regardless of crop grown. For all years, the NO3mass loss in tile drainage water from the H treatment (48 kg N ha−1) was significantly greater than the mass losses from the M (35 kg N ha−1) and L (29 kg N ha−1) treatments, which were not significantly different. The economically optimum N fertilizer rate for corn was between 67 and 135 kg ha−1in 1996 and 114 and 172 kg ha−1in 1998, but the net N mass balance indicated that N was being mined from the soil at these N fertilizer levels and that the system would not be sustainable.
Effects of Tillage and Phosphorus Placement on Phosphorus Runoff Losses in a Grain Sorghum–Soybean Rotation
Authors: Kimmell R.J. , Pierzynski G.M. , Janssen K.A. , Barnes P.L.
Published: June 2010

Phosphorus enhances eutrophication of fresh water bodies. This study was conducted to determine the influence of tillage and P placement on P losses in runoff water from a somewhat poorly drained soil (Woodson silt loam [fine, smectitic, thermic Abruptic Argiaquoll], 1.0–1.5% slope) in a grain sorghum [Sorghum bicolor (L.) Moench]–soybean [Glycine max (L.) Merr] rotation. Chisel‐disk‐field cultivate (ChT), ridge‐till (RT), and no‐till (NT) in combination with 0 kg P ha−1 or 24 kg P ha−1 broadcast or knifed (applied prior to planting grain sorghum) were studied. Runoff volume and losses of sediment and P were summed over the growing season. Significant interactions between tillage and P placement for soluble P losses were found. For example, soluble P loss in 1999 for NT‐broadcast in grain sorghum was 358 g ha−1; significantly greater than 31 g ha−1 for NT‐knife or 23 g ha−1 for NT‐check. Similar results were found for RT but no such differences were found for ChT. Bioavailable P losses were generally highest with broadcast P placement and for NT and RT. Total P losses were significantly higher at 959 g ha−1 with broadcast P on grain sorghum in 1998, compared with 521 g ha−1 for the check and 659 g ha−1 for the knifed P applications. Total P losses in 1999 for soybeans were only 18 g ha−1 for NT, which was significantly lower than 75 g ha−1 for ChT and 66 g ha−1 for RT. The results indicate that broadcast P applications on RT and NT will increase P losses, but the influence of tillage was not consistent.
Controlled Drainage and Wetlands to Reduce Agricultural Pollution: A Lysimetric Study
Authors: Borin M. , Bonaiti G. , Giardini L.
Published: June 2010

Controlled drainage and wetlands could be very effective practices to control nitrogen pollution in the low‐lying agricultural plains of northeast Italy, but they are not as popular as in other countries. An experiment on lysimeters was therefore carried out in 1996–1998, with the double aim of obtaining local information to encourage the implementation of these practices and to gain more knowledge on the effects involved. Controlled drainage + subirrigation and wetlands were all considered as natural systems where alternative water table management could ameliorate water quality, and were compared with a typical water management scheme for crops in the open field. Eight treatments were considered: free drainage on maize (Zea mays L.) and sugarbeet (Beta vulgaris L.), two treatments of controlled drainage on the same crops, and five wetland treatments using common reed [Phragmites australis (Cav.) Trin. ex Steud.], common cattail (Typha latifolia L.), and tufted sedge (Carex elata All.), with different water table or flooding levels. Lysimeters received about 130 g m−2 of N with fertilization and irrigation water, with small differences among treatments. The effects of treatments were more evident for NO3–N concentrations than for the other chemical parameters (total Kjeldahl nitrogen, pH, and electrical conductivity), with significantly different medians among free drainage (33 mg L−1), controlled drainage (1.6 and 2.6 mg L−1), and wetlands (0.5–0.7 mg L−1). Referring to free drainage, NO3–N losses were reduced by 46 to 63% in controlled drainage and 95% in the average of wetlands. Wetlands also reduced losses of total dissolved solids from 253 g m−2 (average of crop treatments) to 175 g m−2 (average of wetlands).
Effect of Flue Gas Desulfurization (FGD) By‐Product on Water Quality at an Underground Coal Mine
Authors: Lamminen Mikko , Wood James , Walker Harold , Chin Yu‐Ping , He Yongtian , Traina Samuel J.
Published: June 2010

In this paper, a field study was carried out to examine the effect of flue gas desulfurization (FGD) by‐product on water quality at an underground coal mine in central‐eastern Ohio. Flue gas desulfurization by‐product was injected into the down‐dip portions of the Roberts–Dawson mine in an attempt to seal major seeps exiting the mine and to coat exposed pyritic surfaces. Immediately following grout injection, significant increases in acidity, iron, aluminum, sulfur, and calcium were observed at most surface and ground water locations near where grouting was carried out. Following this initial flush of elements, concentrations of most constituents have decreased to near pre‐grouting levels. Data from the site and geochemical modeling suggest that an increase in water level or rerouting of drainage flow resulted in the dissolution of iron and aluminum sulfate salts and ferrihydrite. Dissolution of the FGD grout material resulted in increases in calcium and sulfate concentrations in the drainage waters. Water within the mine voids was saturated with respect to calcium sulfate and gypsum immediately following grout injection. Based on an analysis of core samples obtained from the site, acid mine drainage (AMD) was in contact with at least some portions of the grout and this resulted in grout weathering. Subsequent transport of calcium and sulfate to the underclay, perhaps by fracture flow, has resulted in the deposition of gypsum and calcium sulfate solids.
Chemical Analysis of Soil and Leachate from Experimental Wetland Mesocosms Lined with Coal Combustion Products
Authors: Ahn Changwoo , Mitsch William J.
Published: June 2010

Small‐scale (1 m2) wetland mesocosm experiments were conducted over two consecutive growing seasons to investigate the effects on soil and leachate chemistry of using a recycled coal combustion product as a liner. The coal combustion product used as a liner consisted of flue gas desulfurization (FGD) by‐products and fly ash. This paper provides the chemical characteristics of mesocosm soil and leachate after 2 yr of experimentation. Arsenic, Ca, and pH were higher in FGD‐lined mesocosm surface soil relative to unlined mesocosms. Aluminum was higher in the soils of unlined mesocosms relative to FGD‐lined mesocosms. No significant difference of potentially phytotoxic B was observed between lined and unlined mesocosms in the soil. Higher pH, conductivity, and concentrations of Al, B, Ca, K, and S (SO4–S) were observed in leachate from lined mesocosms compared with unlined controls while Fe, Mg, and Mn were higher in leachate from unlined mesocosms. Concentrations of most elements analyzed in the leachate were below national primary and secondary drinking water standards after 2 yr of experimentation. Initially high pH and soluble salt concentrations measured in the leachate from the lined mesocosms may indicate the reason for early effects noted on the development of wetland vegetation in the mesocosms.
Removal and Distribution of Iron, Manganese, Cobalt, and Nickel within a Pennsylvania Constructed Wetland Treating Coal Combustion By‐Product Leachate
Authors: Ye Z.H. , Whiting S.N. , Lin Z.‐Q. , Lytle C.M. , Qian J.H. , Terry N.
Published: June 2010

A flow‐through wetland treatment system was constructed to treat coal combustion by‐product leachate from an electrical power station at Springdale, Pennsylvania. In a nine‐compartment treatment system, four cattail (Typha latifolia L.) wetland cells (designated Cells 1 through 4) successfully removed iron (Fe) and manganese (Mn) from the inlet water; Fe and Mn concentrations were decreased by an average of 91% in the first year (May 1996–May 1997), and by 94 and 98% in the second year (July 1997–June 1998), respectively. Cobalt (Co) and nickel (Ni) were decreased by an average of 39 and 47% in the first year, and 98 and 63% in the second year, respectively. Most of the metal removed by the wetland cells was accumulated in sediments, which constituted the largest sink. Except for Fe, metal concentrations in the sediments tended to be greater in the top 5 cm of sediment than in the 5‐ to 10‐ or 10‐ to 15‐cm layers, and in Cell 1 than in Cells 2, 3, and 4. Plants constituted a much smaller sink for metals; only 0.91, 4.18, 0.19, and 0.38% of the Fe, Mn, Co, and Ni were accumulated annually in the aboveground tissues of cattail, respectively. A greater proportion of each metal (except Mn) was accumulated in cattail fallen litter and submerged Chara (a macroalga) tissues, that is, 2.81, 2.75, and 1.05% for Fe, Co, and Ni, respectively. Considerably higher concentrations of metals were associated with cattail roots than shoots, although Mn was a notable exception.
Phytoremediation of Aged Petroleum Sludge: Effect of Irrigation Techniques and Scheduling
Authors: Hutchinson S. Lewis , Schwab A. P. , Banks M. K.
Published: June 2010

The use of higher plants to accelerate the remediation of petroleum contaminants in soil is limited by, among other factors, rooting depth and the delivery of nutrients to the microsites at which remediation occurs. The objective of this study was to test methods of enhancing root growth and remediation in the subsurface of a contaminated petroleum sludge. The phytoremediation of highly contaminated petroleum sludge (total petroleum hydrocarbons >35 g kg−1) was tested in the greenhouse as a function of the frequency and the depth of irrigation and fertilization. Water and dissolved plant nutrients were added to the soil surface or at a depth of 30 cm, either daily or weekly. Equivalent quantities of water and nutrients were added in all cases. Daily irrigation at a depth of 30 cm invoked greater root growth and enhanced contaminant degradation relative to all other treatments. In the absence of plants, residual concentrations of petroleum hydrocarbons after 7 mo were higher than with plants. The presence of plant roots clearly improved the physical structure of the soil and increased microbial populations. Thus, the plant roots in conjunction with daily additions of soluble N and P appeared to enhance oxygen transport to greater depths in the soil, stimulate petroleum‐degrading microorganisms, and provide microbial access to soil micropores. Subsurface irrigation with frequent, small amounts of water and nutrients could significantly accelerate phytoremediation of field soils contaminated with petroleum hydrocarbons.
Biosolids Applications Affect Runoff Water Quality following Forest Fire
Authors: Meyer V. F. , Redente E. F. , Barbarick K. A. , Brobst R.
Published: June 2010

Soil erosion and nutrient losses are great concerns following forest wildfires. Biosolids application might enhance revegetation efforts while reducing soil erodibility. Consequently, we applied Denver Metro Wastewater District composted biosolids at rates of 0, 40, and 80 Mg ha−1 to a severely burned, previously forested site near Buffalo Creek, CO to increase plant cover and growth. Soils were classified as Ustorthents, Ustochrepts, and Haploborols. Simulated rainfall was applied for 30 min at a rate of 100 mm h−1 to 3‐ × 10‐m paired plots. Biosolids application rates did not significantly affect mean total runoff (p < 0.05). Sediment concentrations were significantly greater (p < 0.05) from the control plots compared with the plots that had received the 80 Mg biosolids ha−1 rate. Biosolids application rate had mixed effects on water‐quality constituents; however, concentrations of all runoff constituents for all treatment rates were below levels recommended for drinking water standards, except Pb. Biosolids application to this site increased plant cover, which should provide erosion control.
Cadmium Content of Wheat Grain from a Long‐Term Field Experiment with Sewage Sludge
Authors: Chaudri Amar M. , Allain Céline M.G. , Badawy S.H. , Adams Martin L. , McGrath Steve P. , Chambers Brian J.
Published: June 2010

Grain Cd concentrations were determined in the wheat (Triticum aestivum L.) cultivars Soissons, Brigadier, and Hereward grown in 1994, 1996, and 1999, respectively, in soils of a long‐term field experiment to which sewage sludges contaminated with Zn, Cu, Ni, or Cr had previously been added. Soil pore water soluble Cd and free Cd2+ increased linearly with increasing total soil Cd (R2 = 0.82 and 0.84, respectively; P < 0.001). Similarly, soil pore water free Cd2+ increased linearly with increasing soil pore water soluble Cd (R2 = 0.98; P < 0.001). There was no evidence of a plateau in soil pore water Cd concentrations with increasing soil Cd concentrations. Grain Cd concentrations were significantly correlated with total soil Cd (P < 0.001), soil pore water Cd (P < 0.001), and free Cd2+ (P < 0.001). A slight curvilinear relationship between grain Cd and soil Cd was apparent, but there was no plateau, even at the maximum soil Cd concentration of about 2.7 mg kg−1 The relationship between soil pore water Cd and grain Cd was linear for all three cultivars. The slopes were in the order 1994 > 1996 > 1999, with more Cd being taken up into the grain by Soissons grown in 1994, and least by Hereward grown in 1999. For Soissons, Cd concentration in the grain greater than the EU limit (0.24 mg kg−1 dry wt.) occurred at soil Cd less than the current UK limit of 3 mg kg−1 for soils receiving sewage sludge. In contrast, for Brigadier and Hereward, grain Cd concentrations were near to and less than the EU limit, respectively, at soil Cd concentrations of 3 mg kg−1
Identifying Riparian Sinks for Watershed Nitrate using Soil Surveys
Authors: Rosenblatt A. E. , Gold A. J. , Stolt M. H. , Groffman P. M. , Kellogg D. Q.
Published: June 2010

The capacity of riparian zones to serve as critical control locations for watershed nitrogen flux varies with site characteristics. Without a means to stratify riparian zones into different levels of ground water nitrate removal capacity, this variability will confound spatially explicit source–sink models of watershed nitrate flux and limit efforts to target riparian restoration and management. We examined the capability of SSURGO (1:15840 Soil Survey Geographic database) map classifications (slope class, geomorphology, and/or hydric soil designation) to identify riparian sites with high capacity for ground water nitrate removal. The study focused on 100 randomly selected riparian locations in a variety of forested and glaciated settings within Rhode Island. Geomorphic settings included till, outwash, and organic/alluvial deposits. We defined riparian zones with “high ground water nitrate removal capacity” as field sites possessing both >10 m of hydric soil width and an absence of ground water surface seeps. SSURGO classification based on a combination of geomorphology and hydric soil status created two functionally distinct sets of riparian sites. More than 75% of riparian sites classified by SSURGO as organic/alluvium–hydric or as outwash–hydric had field attributes that suggest a high capacity for ground water nitrate removal. In contrast, >85% of all till sites and nonhydric outwash sites had field characteristics that minimize the capacity for ground water nitrate removal. Comparing the STATSGO and SSURGO databases for a 64000‐ha watershed, STATSGO grossly under‐represented critical riparian features. We conclude that the SSURGO database can provide modelers and managers with important insights into riparian zone nitrogen removal potential.
Effect of Turfgrass Cover and Irrigation on Soil Mobility and Dissipation of Mefenoxam and Propiconazole
Authors: Gardner D. S. , Branham B. E.
Published: June 2010

Irrigation effects on pesticide mobility have been studied, but few direct comparisons of pesticide mobility or persistence have been conducted on turfgrass versus bare soil. The interaction of irrigation practices and the presence of turfgrass on the mobility and dissipation of mefenoxam [N‐(2,6‐dimethylphenyl)‐N‐(methoxyacetyl)‐D‐alanine methyl ester] and propiconazole (1‐[[2‐(2,4‐dichlorophenyl)‐4‐propyl‐1,3‐dioxolan‐2‐yl]methyl]‐1H‐1,2,4‐triazole) was studied. Sampling cylinders (20‐cm diam.) were placed in either creeping bentgrass [Agrostis stolonifera L. var. palustris (Huds.) Farw.] or bare soil. Mefenoxam was applied at 770 g a.i. ha−1 and propiconazole was applied at 1540 g a.i. ha−1 on 14 June 1999. Sampling cylinders were removed 2 h after treatment and 4, 8, 16, 32, and 64 days after treatment (DAT) and the cores were sectioned by depth. Dissipation of mefenoxam was rapid, regardless of the amount of surface organic matter or irrigation. The half‐life (t1/2) of mefenoxam was 5 to 6 d in turf and 7 to 8 d in bare soil. Most mefenoxam residues found in soil under turfgrass were in the 0‐ to 1‐cm section at 0, 4, and 8 DAT. Residues were found in the 15‐ to 30‐cm section at 4, 8, 16, 32, and 64 DAT, regardless of turf cover or irrigation. The t1/2 of propiconazole was 12 to 15 d in turfgrass and 29 d in bare soil. Little movement of propiconazole was observed in either bare soil or turf.
Coupled Effects of Treated Effluent Irrigation and Wetting–Drying Cycles on Transport of Triazines through Unsaturated Soil Columns
Authors: Seol Yongkoo , Lee Linda S.
Published: June 2010

The physical and chemical parameters controlling the movement of atrazine (6‐chloro‐N2‐ethyl‐N4‐isopropyl‐1,3,5‐triazine‐2,4‐diamine; 98.8%) and prometryn [N,N′‐bis(1‐methylethyl)‐6‐(methylthio)‐1,3,5‐triazine‐2,4‐diamine; 99.5%] were investigated in columns infiltrated with treated effluent under unsaturated transient conditions and subjected to drying events at 22 or 60°C followed by rewetting. Three soils varying in soil pH and texture and three solutions were used. The infiltrating solutions consisted of either a CaCl2 matrix (CC), a swine waste–derived lagoon effluent (SW), or a simulated buffer solution (SB) representative of the element composition and pH of the SW but with no dissolved organic matter. Several parameters were monitored including leachate triazine concentrations, pH, dissolved organic carbon (DOC), inorganic carbon, and flow rates. Compared with CC, application of SW and SB increased column leachate pH, enhanced dissolution of organic carbon and particle dispersion, and decreased average flow rates, which allowed for increased desorption time. The coupled effect of these processes enhanced movement of triazines in some cases, with SW generally having the greatest effect. The individual effect of increased pH was more pronounced for prometryn (pKa = 4.05) versus atrazine (pKa = 1.66), and most dramatic for the soil with the lowest initial pH. High‐temperature drying, which simulated intensive evaporation, further enhanced the dissolution of soil organic matter and the reduction in leachate flow rates with SW and SB applications; however, the net effect under the experimental conditions employed varied with soil type. Relative to low‐temperature drying, high‐temperature drying in the silty clay loam–packed columns reduced pesticide migration.
Ryegrass Cover Crop Effects on Nitrate Leaching in Spring Barley Fertilized with 15NH415NO3
Authors: Bergström Lars F. , Jokela William E.
Published: June 2010

Cover crops are a management option to reduce NO3 leaching under cereal grain production. A 2‐yr field lysimeter study was established in Uppsala, Sweden, to evaluate the effect of a perennial ryegrass (Lolium perenne L.) cover crop interseeded in barley (Hordeum vulgare L.) on NO3–N leaching and availability of N to the main crop. Barley and ryegrass or barley alone were seeded in mid‐May 1992, in lysimeters (0.3‐m diam. × 1.2‐m depth) of an undisturbed, well‐drained, sandy loam soil. Fertilizer N was applied at the same time as labeled 15NH415NO3 (10 atom % 15N) at a rate of 100 kg N ha−1 In 1993, barley was reseeded in May in the lysimeters but with nonlabeled NH4NO3 and no cover crop (previous year's cover crop incorporated just prior to seeding). Barley yields and total and fertilizer N uptake in Year 1 (1992) were unaffected by cover crop. Total aboveground N uptake by the ryegrass was 28 kg ha−1 at the time of incorporation the following spring. Recovery of fertilizer‐derived N in May 1993 was about 100%; 53% in soil, 46% in barley, <2% in ryegrass, and negligible amounts in leachate. In May 1994, the corresponding figures were: 32% in soil, <3% in barley, and, again, negligible amounts in leachate. The cover crop reduced concentrations of NO3–N in the leachate considerably (<5 mg L−1, compared with 10 to 18 mg L−1 without cover crop) at most sampling times from November 1992 to April 1994, and reduced the total amount of NO3–N leached (22 compared with 8 kg ha−1).
Distribution and Movement of Sludge‐Derived Trace Metals in Selected Nigerian Soils
Authors: Mbila Monday O. , Thompson Michael L. , Mbagwu Joe S. C. , Laird David A.
Published: June 2010

Use of metal‐rich sewage sludge as soil fertilizer may result in trace‐metal contamination of soils. This study was conducted to evaluate the effects of long‐term sludge application on trace‐metal (Zn, Cu, Pb, and Ni) distribution and potential bioavailability in Nigerian soils under a tropical wet–dry climate. Total metal analyses, sequential chemical fractionation, and DTPA extractions were carried out on samples of control and sludge‐amended pedons in Nigeria (a Rhodic Kandiustult and two Rhodic Kandiustalfs from Nigeria, respectively). The sewage sludge applied to the soils contained higher levels of Zn and Cu than Pb and Ni. The control pedon contained low levels of all four metals. Soil enrichment factors (EF) were calculated for each metal in the sludge‐amended pedons. Compared with the control soil, the sludge‐amended pedons showed elevated levels of Zn and Cu, reflecting the trace‐metal composition of the sewage sludge. Zinc and Cu in the sludge‐amended soils were strongly enriched at all depths in the profile, indicating that they had moved below the zone of sludge application. The sequential extraction and DTPA analyses indicated that the sludge‐amended soils contained more readily extractable and bioavailable metal ions than the unamended soil.
Manure Phosphorus Extractability as Affected by Aluminum‐ and Iron By‐Products and Aerobic Composting
Authors: Dao Thanh H. , Sikora L. J. , Hamasaki A. , Chaney R. L.
Published: June 2010

Shifts in manure phosphorus (P) chemical forms and pool sizes induced by water treatment residuals and industrial mineral by‐products are largely undefined. We conducted a manure P fractionation study to determine mechanisms of reduction of dissolved reactive phosphorus (DRP) in poultry manure upon mineral by‐product additions. The effects of composting on the P immobilization efficacy of the by‐products were determined using laboratory self‐heating composting simulators. The mineral by‐products included an aluminum‐water treatment residual (Al‐WTR) and an iron‐rich titanium‐processing by‐product. The noncomposted manure averaged 0.11 g g−1 of total P as DRP forms. The by‐products significantly reduced manure DRP, by an average of 39 and 48% in the Al‐ and the Fe‐treated manure, respectively. The by‐products also reduced the 0.5 M NH4F–extractable phosphorus (FEP) fraction. Shifts in P forms between FEP and 0.1 M NaOH–extractable phosphorus (SHEP) depended upon the Al and Fe contents of the by‐products while the combined FEP + SHEP pool remained constant. Phosphate sorption measurements supported the observations that the Fe‐rich by‐product was more effective at reducing manure DRP and enhancing the formation of SHEP forms at the expense of FEP than the Al‐WTR. Composting had no effect on the efficacy of either by‐product to reduce DRP. Potential mechanisms of enhanced P stabilization in treated manure upon composting included chemical shifts from the DRP and FEP fractions to the citrate–bicarbonate–dithionite extractable P fraction. Thus, the choice of P immobilization agents affected the stability of immobilized P forms and should be taken into consideration in developing manure processing and nutrient stabilization methods.
Leachate Chemistry of Field‐Weathered Spent Mushroom Substrate
Authors: Guo Mingxin , Chorover Jon , Rosario Rex , Fox Richard H.
Published: June 2010

Passive leaching by rainfall and snowmelt is a popular method to treat piles of spent mushroom substrate (SMS) before its reuse. During this field weathering process, leachate percolates into the underlying soils. A field study was conducted to examine the chemistry of SMS leachate and effects of infiltration. Two SMS piles were deposited (90 and 150 cm in height) over a Typic Hapludult and weathered for 24 mo. Leachate was collected biweekly using passive capillary samplers. The SMS leachate contained high concentrations of dissolved organic carbon (DOC; 0.8–11.0 g L−1), dissolved organic nitrogen (DON; 0.1–2 g L−1), and inorganic salts. The pH, electrical conductivity, and acid neutralizing capacity were 6.6 to 9.0, 21 to 66 ds m−1, and 10 to 75 mmolc L−1, respectively. Inorganic chemistry of the leachate was dominated by K+, Cl−, and SO2−4 Leachate DOC was predominantly low molecular weight (<1000 Da) organic acids. During 2 yr of weathering, the 90‐cm SMS pile released (per cubic meter of SMS) 3.0 kg of DOC, 1.6 kg of dissolved N, and 26.6 kg of inorganic salts. The 150‐cm pile released (per cubic meter of SMS) 2.8 kg of DOC, 0.7 kg of dissolved N, and 13.6 kg of inorganic salts. The 150‐cm pile retained more water and exhibited lower net nitrification compared with the 90‐cm pile. The top 90 cm of soil retained 20 to 89% of the leachate solutes. Weathering of SMS in piles of 90 cm depth or greater may adversely affect ground water quality.
Trace Element Removal from Coal Ash Leachate by a 10‐Year‐Old Constructed Wetland
Authors: Ye Z. H. , Whiting S. N. , Qian J. H. , Lytle C. M. , Lin Z.‐Q. , Terry N.
Published: June 2010

This study investigated the ability of a 10‐yr‐old constructed wetland to treat metal‐contaminated leachate emanating from a coal ash pile at the Widows Creek electric utility, Alabama (USA). The two vegetated cells, which were dominated by cattail (Typha latifolia L.) and soft rush (Juncus effusus L.), were very effective at removing Fe and Cd from the wastewater, but less efficient for Zn, S, B, and Mn. The concentrations were decreased by up to 99% for Fe, 91% for Cd, 63% for Zn, 61% for S, 58% for Mn, and 50% for B. Higher pH levels (>6) in standing water substantially improved the removing efficiency of the wetland for Mn only. The belowground tissues of both cattail and soft rush had high concentrations of all elements; only for Mn, however, did the concentration in the shoots exceed those in the belowground tissues. The concentrations of trace elements in fallen litter were higher than in the living shoots, but lower than in the belowground tissues. The trace element accumulation in the plants accounted for less than 2.5% of the annual loading of each trace element into the wetland. The sediments were the primary sinks for the elements removed from the wastewater. Except for Mn, the concentrations of trace elements in the upper layer (0–5 cm) of the sediment profile tended to be higher than the lower layers (5–10 and 10–15 cm). We conclude that constructed wetlands are still able to efficiently remove metals in the long term (i.e., >10 yr after construction).
Cesium‐134 as a Tracer to Study Particle Transport Processes within a Small Catchment with a Buffer Zone
Authors: Syversen Nina , Øygarden Lillian , Salbu Brit
Published: June 2010

The purpose of the study is to use soil particles labeled with the radioactive tracer cesium‐134 (134Cs) as a method for studying soil erosion and sedimentation pattern within a small catchment with buffer zones. Cesium is adsorbed to soil particles, and by measuring changes in the 134Cs activity on the soil surface, erosion, sedimentation, and pathways for particles can be traced. A harrowed area was surface‐contaminated with 134CsCl, while the buffer zone was left uncontaminated. A grid net in the tilled plot and buffer zone was established for in situ measurements of the 134Cs activity after major runoff events from October 1993 to May 1996. In addition, 134Cs activity and suspended solids in runoff were followed during the events. At the end of the experiment, the vertical distribution of 134Cs in soil profiles and uptake of 134Cs in vegetation within the buffer zone were determined. At the end of the experiment, about 54% of the applied tracer remained at the soil surface. Surface soil erosion occurred relatively uniformly across the hillslope due to sheet flow. Most of the tracer was transported vertically into the soil profile, probably during the first heavy rainfall 3 wk after application when the soil was newly tilled. Sedimentation occurred in the upper part of the buffer zone. The correlation between suspended particles in runoff and 134Cs activity was good (R2 = 0.76). The study also demonstrates the benefit of utilizing 134Cs2+ tracer for investigating transport pathways for contaminated particles within a hillslope system without disturbing the surface soil system.
Herbicide and Nutrient Transport from an Irrigation District into the South Saskatchewan River
Authors: Cessna A. J. , Elliott J. A. , Tollefson L. , Nicholaichuk W.
Published: June 2010

Pesticides and nutrients can be transported from treated agricultural land in irrigation runoff and thus can affect the quality of receiving waters. A 3‐yr study was carried out to assess possible detrimental effects on the downstream water quality of the South Saskatchewan River due to herbicide and plant nutrient inputs via drainage water from an irrigation district. Automated water samplers and flow monitors were used to intensively sample the drainage water and to monitor daily flows in two major drainage ditches, which drained approximately 40% of the flood‐irrigated land within the irrigation district. Over three years, there were no detectable inputs of ethalfluralin into the river and those of trifluralin were less than 0.002% of the amount applied to flood‐irrigated fields. Inputs of MCPA, bromoxynil, dicamba and mecoprop were 0.06% or less of the amounts applied, whereas that for clopyralid was 0.31%. The relatively higher input (1.4%) of 2,4‐D to the river was probably due its presence in the irrigation water. Corresponding inputs of P (as total P) and N (as nitrate plus ammonia) were 2.2 and 1.9% of applied fertilizer, respectively. Due to dilution of the drainage water in the river, maximum daily herbicide (with the exception of 2,4‐D) and nutrient loadings to the river would not have resulted in significant concentration increases in the river water. There was no consistent remedial effect on herbicides entering the river due to passage of the drainage water through a natural wetland. In contrast, a considerable portion of the nutrients entering the river originated from the wetland.
Management Practice Effects on Phosphorus Losses in Runoff in Corn Production Systems
Authors: Bundy L. G. , Andraski T. W. , Powell J. M.
Published: June 2010

Phosphorus losses in runoff from cropland can contribute to nonpoint‐source pollution of surface waters. Management practices in corn (Zea mays L.) production systems may influence P losses. Field experiments with treatments including differing soil test P levels, tillage and manure application combinations, and manure and biosolids application histories were used to assess these management practice effects on P losses. Runoff from simulated rainfall (76 mm h−1) was collected from 0.83‐m2 areas for 1 h after rainfall initiation and analyzed for dissolved reactive P (DRP), bioavailable P, total P (TP), and sediment. In no‐till corn, both DRP concentration and load increased as Bray P1 soil test (STP) increased from 8 to 62 mg kg−1 A 5‐yr history of manure or biosolids application greatly increased STP and DRP concentrations in runoff. The 5‐yr manure treatment had higher DRP concentration but lower DRP load than the 5‐yr biosolids treatment, probably due to residue accumulation and lower runoff in the manure treatment. Studies of tillage and manure application effects on P losses showed that tillage to incorporate manure generally lowered runoff DRP concentration but increased TP concentration and loads due to increased sediment loss. Management practices have a major influence on P losses in runoff in corn production systems that may overshadow the effects of STP alone. Results from this work, showing that some practices may have opposite effects on DRP vs. TP losses, emphasize the need to design management recommendations to minimize losses of those P forms with the greatest pollution potential.
Differentiating Nonpoint Sources of Deisopropylatrazine in Surface Water Using Discrimination Diagrams
Authors: Meyer M. T. , Thurman E. M. , Goolsby D. A.
Published: June 2010

Pesticide degradates account for a significant portion of the pesticide load in surface water. Because pesticides with similar structures may degrade to the same degradate, it is important to distinguish between different sources of parent compounds that have different regulatory and environmental implications. A discrimination diagram, which is a sample plot of chemical data that differentiates between different parent compounds, was used for the first time to distinguish whether sources other than atrazine (6‐chloro‐N2‐ethyl‐N4‐isopropyl‐1,3,5‐triazine‐2,4‐diamine) contributed the chlorinated degradate, deisopropylatrazine (DIA; 6‐chloro‐N‐ethyl‐1,3,5‐triazine‐2,4‐diamine) to the Iroquois and Delaware Rivers. The concentration ratio of deisopropylatrazine to deethylatrazine [6‐chloro‐N‐(1‐methylethyl)‐1,3,5‐triazine‐2,4‐diamine], called the D2R, was used to discriminate atrazine as a source of DIA from other parent sources, such as cyanazine (2‐[[4‐chloro‐6‐(ethylamino)‐1,3,5‐triazin‐2‐yl]amino]‐2‐methylpropionitrile) and simazine (6‐chloro‐N,N′‐diethyl‐1,3,5‐triazine‐2,4‐diamine). The ratio of atrazine to cyanazine (ACR) used in conjunction with the D2R showed that after atrazine, cyanazine was the main contributor of DIA in surface water. The D2R also showed that cyanazine, and to a much lesser extent simazine, contributed a considerable amount (∼40%) of the DIA that was transported during the flood of the Mississippi River in 1993. The D2R may continue to be a useful discriminator in determining changes in the nonpoint sources of DIA in surface water as cyanazine is currently being removed from the market.