bluuebunny/crossref_metadata_2025 huggingface dataset:
Acidic Precipitation Effects on Crops: A Review and Analysis of Research
Authors: Irving Patricia M.
Published: July 2010

For more than a century it has been known that vegetative growth is affected by the products of fossil fuel combustion. Recently, the acidic deposition phenomenon has gained increasing attention, especially when implicated as a factor responsible for economic loss. Research has been directed toward quantification of effects; however, limitations in the design of many crop studies restricts the usefulness and applicability of the results. Acidic deposition varies in a number of ways that may affect crop yield (i.e., level of acidity, amount and intensity of rain, S and N doses). The responses to these variables may be nonlinear. To allow comparisons of published acid precipitation effects research, calculations for this review were made (based on information in the literature or from personal communication) to describe the experimental conditions, the various dose parameters, and the responses in comparable units for each investigation.

The majority of crop species studied in field and controlled environment experiments exhibited no effect on growth nor yield as a result of simulated acidic rain. The growth and yield of some crops, however, was negatively affected by acidic rain; others exhibited a positive response. This analysis of the current literature concludes that the effects of acidic precipitation on crops appear to be minimal and that when responses are observed, they may be positive or negative. More complex experimental designs and analyses may be necessary in order to examine and describe the possible subtle responses of agricultural systems to acidic precipitation.
Effects of Acidity and Alkalinity on the Stability of Amidohydrolases in Freshwater
Authors: Frankenberger W. T. , Page A. L.
Published: July 2010

The influence of acidity and alkalinity on the enzymatic hydrolysis of amide‐N in the aquatic system was investigated by determining the stability of L‐asparaginase (EC [Enzyme Commission] 3.5.1.1). L‐glutaminase (EC 3.5.1.2), and amidase (EC 3.5.1.4), and urease (EC 3.5.1.5) with respect to pH in three freshwater lakes. The water samples were first incubated at the indicated buffer pH (1–13) for 24 h; then each enzyme was assayed at its optimal pH (pHopt) under standardized conditions. L‐Asparaginase retained essentially 100% of its activity within the pH range of 6–7 in Lake Evans and Lake Matthews, and 5–7 in Lake Perris. L‐Glutaminase was active between pH 6 and 7 in the water samples surveyed. Amidase remained completely active at pH ranges of 4–8 in Lake Evans, 4–7 in Lake Matthews, and 5–8 in Lake Perris. Urease remained active over a broad pH range of 5–9 in Lake Evans, 5–8 in Lake Matthews, and 4–8 in Lake Perris. There was a progressive loss in enzyme activity below and above these pH ranges. The results suggest that the decline in aquatic amidohydrolase activities in relation to the pH‐profile near their pHopt was caused by a reversible reaction involving the ionization or deionization of functional groups of the active center of the protein, but under highly acidic or alkaline conditions (pH < 4 to > 9) the reduced activity appears to be due to irreversible inactivation of the enzyme.
Trace Metal and Mineral Composition of Milk and Blood from Goats Fed Silage Produced on Sludge‐Amended Soil
Authors: Dowdy R. H. , Bray B. J. , Goodrich R. D.
Published: July 2010

The transfer of heavy metals from sewage sludge into the food and feed chain is a significant concern to the health of humans and animals. We measured the accumulation of trace metals in the milk and blood of dairy goats (Capra hircus) fed corn (Zea mays L.) silage grown on sludge‐amended vs. conventionally fertilized soil for 3 consecutive years. The silage contained levels of Cd up to 5.3 mg/kg. Zinc, the only other sludge‐borne metal that was accumulated by corn, was accumulated to a lesser extent than Cd, which resulted in low Zn/Cd ratios.

The Cd concentrations of goat milk were not increased, even though the animals received as much as 5 mg Cd each day from corn silage containing high levels of bioaccumulated Cd.

Zinc levels in milk decreased as the amount of silage‐borne Zn increased within the three treatments fertilized with sludge, but no differences were noted when the control treatment was contrasted with all sludge treatments. Goat's milk from animals on the control treatment contained higher levels of Cu than milk from animals of the various sludge‐fertilized treatments. The higher levels of Cd in silage from the sludge‐amended treatments may have limited Cu absorption by the animals.

The elemental concentrations of 14 other metals and minerals in milk were not affected by treatment nor time within the lactation period. Although colostrum generally contained higher concentrations of most minerals, no treatment effect was observed. As was true with milk composition, Cu was the only element in blood that was consistently affected by treatment. Copper levels in blood were higher for animals of the control treatment, even though all animals received a Cu‐containing trace mineralized salt ad libitnm.
Heavy Metals in Northern Fur Seals (Callorhinus ursinus) from the Pribilof Islands, Alaska
Authors: Goldblatt Craig J. , Anthony Robert G.
Published: July 2010

Samples of liver, kidney, muscle, and bone were collected from northern fur seals (Callorhinus ursinus) from St. Paul Island, Alaska during the summer of 1975 and analyzed for Cd, Zn, Pb, Ni, and Hg. Positive correlations existed between age of the seals and concentrations of Cd in liver, muscle, and bone, and Hg in liver. Concentrations of Zn, Pb, and Ni were not significantly correlated with age. Cd residues in kidney and liver samples were higher than those reported in 1970–1971 for the same species, suggesting increased contamination of this metal in the food chain of northern fur seals. Concentrations of Pb and Ni were low and those of Zn were similar to levels found in other mammals, including man. Levels of Hg were considerably lower than those reported for other pinnipeds. Among the four tissues sampled, Cd and Zn concentrations were significantly higher in kidneys, whereas concentrations of Pb and Ni were highest in bone.
Suspended Solids and Phosphorus Loads from a Clay Soil: I. Plot Studies
Authors: Culley J. L. B. , Bolton E. F. , Bernyk V.
Published: July 2010

Phosphorus and suspended solids (SS) contents in tile discharge from two southwestern Ontario clay soil drainage experiments were measured over a 2‐y period. For continuous corn (Zea mays L.) plots, loads of SS and total P were 407 and 0.88 kg ha−1 y−1, respectively. Suspended solids and total P loads from drains beneath permanent sod were 97 and 1.85 kg ha−1 y−1, respectively. Comparison of these results with limited data on P and SS loads in surface runoff indicated that >50% of the total P load from these nearly level plots may be lost via subsurface tile flow. Overall, 34% of the total P load from subsurface drains was sediment‐associated. Furthermore, crop cover, P fertilization rate, and tile drain depth were found to significantly affect dissolved P export. Dissolved P concentrations in effluent from permanent bluegrass sod exceeded those from continuous corn and rotational plots. Subsurface sediment and sediment‐associated P loads were highest from continuous corn. Greater soil cover over the tile line decreased both sediment and P concentrations. Sediment‐associated P concentrations increased with P fertilization rate at one of the experimental locations.
Nitrogen Loss from Freshwater and Saline Estuarine Sediments
Authors: Smith C. J. , De Laune R. D.
Published: July 2010

The magnitude of ammonium‐N (NH4+‐N) loss from nitrification‐denitrification reactions in bottom sediments collected from saline and freshwater Louisiana Gulf Coast lakes was determined. Studies were conducted in the laboratory and field. Maximum gaseous N accumulation, from fresh‐water and saline sediment amended with 4.5 µg nitrate‐N (NO4−‐N) g−1 (on dry‐wt basis), was 1.6 and 1.4 µg N g−1, respectively. The addition of 50 µg NH4+‐N g−1 stimulated the evolution of N2O from both sediments, and represents 0.02 and 0.2% of the NH4+‐N applied to the saline and fresh sediment, respectively. Nitrous oxide (N2O) emissions measured in the field were low. The annual N2O emission was 10 and 34 mg N m−2 from the saline and freshwater lakes. These values agree closely with the N2O emission rates calculated from laboratory data.

Denitrification was also estimated from NH4+‐N amended sediment using the acetylene (C2H2) inhibition technique and 15N balance. Recovery of 15N decreased rapidly during the 0‐ to 8‐week period when high denitrification rates were measured. The denitrification rate estimated from 15N recovery during the 0‐ to 8‐week period was 3.7 mg N m−2 d−2 for each sediment. Approximately 50% of the added 15N was lost, an amount equivalent to 1.4 g N m−2 y−1. As the added 15NH4+‐N was incorporated into the organic N pool, little or no further 15N was lost.
Soil Sorption and Alfalfa Uptake of Strychnine
Authors: Miller Glenn C. , Miller W. W. , Hanks Larry , Warren John
Published: July 2010

Strychnine (C21H22N2O2) sorption on soils and uptake in alfalfa (Medicago sativa L.) were investigated. Using application rates of 52–1040 mg/L strychnine, sorption isotherms were developed on three Nevada soils. Strychnine was found to sorb strongly to the three soils studied; however, isotherms were all nonlinear and the extent of sorption varied with each soil. Desorption characteristics paralleled sorption isotherms, indicating reversibility. Strychnine extraction with ammonium chloride (NH4Cl) solutions was greater than that obtained with water extraction on all soils. An apparent relationship between specific surface area, cation exchange capacity (CEC), and total strychnine sorption was noted. Strychnine movement through soil columns under saturated flow was also investigated for the three soils. These results were similar to the sorption studies in that the soil with the lowest sorptive capacity also required the fewest pore volumes for the eluting strychnine concentration to equal that of the starting concentration. The binding mechanism of strychnine to soil is suggested to be a combination of cation exchange and surface absorption to the organic and inorganic fractions of soil. Potential uptake of strychnine in alfalfa was investigated by applying treated milo (Sorghum vulgare var. subglabrescens) bait to the base of alfalfa plants at rates that exceeded normal rodent treatments. Strychnine was not detected (detection limit 0.03 mg/kg) in whole alfalfa samples taken 4 and 11 d following treatment. The data indicate that strychnine is relatively immobile in soil systems, particularly those of moderate‐to‐high CEC, and is not expected to leach rapidly nor be significantly taken up by plants.
Azinphosmethyl and Fenvalerate Runoff Loss from a Sugarcane‐Insect IPM System
Authors: Smith S. , Reagan T. E. , Flynn J. L. , Willis G. H.
Published: July 2010

Azinphosmethyl {0,0‐dimethyl S‐[(4‐oxo‐1,2,3‐benzotriazin‐3(4H)‐yl)methyl] phosphorodithioate} and fenvalerate [(RS)‐α‐cyano‐3‐phenoxybenzyl (RS)‐2‐(4‐chlorophenyl)‐3‐methylbutyrate] were applied to sugarcane (Saccharum officinarum L.) runoff plots at rates of 0.84 and 0.22 kg/ha, respectively, 4 times each year in 1980 and 1981 as part of an insect integrated pest management (IPM) system research evaluation for season‐long control of the primary sugarcane insect pest, the sugarcane borer [Diatraea saccharalis (F.)]. Runoff samples (water + sediment) were collected within 8 h after each storm and analyzed by gas chromatography. In 1980, runoff losses of azinphosmethyl and fenvalerate were 0.08 and 0.02%, respectively, of the amount applied. Runoff in 1981 was about twice that in 1980, partially accounting for larger insecticide runoff losses measured, 0.55 and 0.56% of that applied for azinphosmethyl and fenvalerate, respectively. The larger 1981 losses also were attributed to shorter time intervals between insecticide applications and runoff events. Azinphosmethyl concentrations in runoff do not appear to be harmful to surrounding aquatic habitats, whereas fenvalerate concentrations might present problems, particularly if applied at 0.22 kg/ha rates.
Response of Soybeans to Simulated Acid Rain in the Field
Authors: Heagle Allen S. , Philbeck Robert B. , Brewer Patricia F. , Ferrell Ronald E.
Published: July 2010

Soybeans [Glycine max (L.) Merr, ‘Davis’] were grown in the field during 1979 and 1980 to determine whether the acidity of simulated rainfall would affect plant injury, growth, or yield, soil chemistry, soil nematode populations, and Rhizobium nodulation of roots. Plants were exposed twice weekly to 0.74 cm (1979) or 0.85 cm (1980) of simulated rain at pH levels of 5.5, 4.0, 3.2, or 2.8 in 1979 and 5.4, 4.1, 3.2, or 2.4 in 1980. There were six 3‐m2 plots (replicates) for each pH level. Simulated rain at pH 2.8 or 2.4 caused small amounts of foliar injury evident as biracial white or tan lesions primarily on young leaves. However, plant growth, pod yield, foliar elemental content, seed protein content, seed oil content, Rhizobium nodulation of roots, and populations of parasitic nematodes were not affected. Soil analyses were performed before, midway through, and after each season. Trends toward lower soil pH, and less Ca, Mg, and K occurred with increased acidity of simulated rain. These effects were statistically significant only for soil pH, Mg, and K at treatment pH 2.4. Possible effects of ambient rain at current pH levels on agricultural soils are likely to require long‐term deposition.
Kinetics of the Microbial Degradation of 2,4‐D in Soil: Effects of Temperature and Moisture
Authors: Parker L. W. , Doxtader K. G.
Published: July 2010

The effects of soil moisture tension and temperature on the kinetics of the degradation of (2,4‐dichlorophenoxy)acetic acid (2,4‐D) in an Ascalon sandy loam were studied under laboratory conditions to develop a simulation model. Degradation occurred by a slow, first‐order reaction (slow phase) which, under some conditions, was followed by a rapid, first‐order reaction (fast phase). The optimum temperature and moisture tension were 27°C and 0.1 bar, respectively. Degradation rates under optimum conditions were 0.230 and 2.234 µg g−1 soil for the slow and fast phases, respectively. At temperatures above the optimum, no fast phase was observed. The activation energy (EA) values increased from 22.96 to 45.46 kcal mole−1, with increasing soil moisture tension in the range from 0.1 to 1.0 bar. The rate of decomposition of 2,4‐D decreased with increasing soil moisture tension for temperatures between 20 and 35°C. This decrease was a result of the reduced activity of the 2,4‐D‐degrading microorganisms arising from decreased water availability and increased 2,4‐D solution concentration.
Behavior Assessment Model for Trace Organics in Soil: I. Model Description
Authors: Jury W. A. , Spencer W. F. , Farmer W. J.
Published: July 2010

A mathematical model is introduced for describing transport and loss of soil‐applied organic chemicals. The model assumes linear, equilibrium partitioning between vapor, liquid, and adsorbed chemical phases, net first order degradation, and chemical movement to the atmosphere by volatilization loss through a stagnant air boundary layer at the soil surface. From these assumptions and the assumption of steady state upward or downward water flow, an analytic solution is derived for chemical concentration and volatilization flux.

This model, which is intended to classify and screen organic chemicals for their relative susceptibility to different loss pathways (volatilization, leaching, degradation) in the soil and air, requires knowledge of the organic carbon partition coefficient (Koc), Henry's constant (KH), and net, first‐order degradation rate coefficient or chemical half‐life to use on a given chemical.

Illustration of the outputs available with the model is shown for two pesticides, lindane (γ‐1,2,3,4,5,6‐hexachlorocyclohexane) and 2,4‐D [(2,4‐dichlorophenoxy)acetic acid], which have widely differing chemical properties. Lindane, with a large Koc, large KH, and small degradation rate coefficient, is shown to be relatively immobile, persistent, and susceptible to volatilization. 2,4‐D, with a small Koc, small KH, and large degradation rate coefficient, is mobile and degrades rapidly, but is only slightly susceptible to losses by volatilization.
Fate of Oxygen and Refractory Organics in Marmot Basin Streams: Seasonal Variations
Authors: Telang S. A. , Hodgson G. W.
Published: July 2010

A conceptual process reactor model with input‐output functions developed for the mountain streams of the Marmot Basin (Alberta, Canada) showed seasonal trends in the conversion of organic matter. Based on mass balance data, organic compounds (e.g., tannins and lignins), and total organic C showed net gains in the stream waters in winter; in spring, the compounds tend to be depleted in waters; in the fall, humics and tannins and lignins underwent net depletion. The indicated changes of accumulation and depletion ranged from +95 to −42% of incoming mass. The chemical O2 demand showed gains in the stream waters throughout the season. The biological O2 demand showed little change throughout the seasons. Photochemical processes appeared to be important processes in the conversion of organic matter in clear, cold mountain streams of the Marmot Basin. Biological uptake of refractory compounds appeared to be a minor process.
Mobility and Retention of Heavy Metals in Sandy Soils
Authors: Miller W. P. , Mc Fee W. W. , Kelly J. M.
Published: July 2010

The sandy soils of industrialized northwestern Indiana are contaminated with aerially deposited Cd, Zn, Cu, and Pb, which are retained largely in the upper 5 cm of soil. To evaluate the leaching of these metals, intact soil cores of the Oakville (Typic Udipsamment) series sampled from forested sites in this area were leached in the laboratory with acidified or metal‐containing solutions corresponding to 1 or 10 y of simulated rainfall. Metals in the leachate were below detection limits, and analyses of core sections showed that the applied Cd, Zn, Cu, and Pb were concentrated in the litter layer and top 2.5 cm of soil. Adsorption experiments performed on 0‐ to 2.5‐cm samples of Oakville soil containing initial levels of 5 µg Cd, 1000 µg Zn, 100 µg Cu, and 200 µg Pb/g soil demonstrated that these soils could retain up to twice the amounts of metals initially present. A similar soil with lower pH and less organic matter adsorbed less of all the metals, while showing higher retention of Cu and Pb compared with Cd and Zn. Sequential extraction of the sorbed metals showed that chelation by organic matter (Na4P2O2‐extractable) and surface reaction with carbonates and/or Fe oxides (EDTA‐extractable) were the most likely retention mechanisms in the Oakville soil, although adsorption on cation exchange sites was observed for Cd and Zn at high loading rates.
Detection of Aspergillus Flavus and Aflatoxins in Cotton and Corn by Ultraviolet Fluorescence
Authors: Marsh Paul B. , Simpson Marion E.
Published: July 2010

A 1954 report from the Beltsville Agricultural Research Center recorded the observation of a bright greenish‐yellow fluorescence or “BGYF” in raw cotton (Gossypium hirsutum L.) fiber and linked it to a previously unrecognized boll rot caused by Aspergillus flavus Link ex Fr.). Nine surveys employing the fluorescence as a detection device on U.S. cotton fiber produced during 1957 to 1981 showed this boll rot mostly in especially hot growing areas in southern California, Arizona, and Texas. The BGY‐fluorescing substance was produced in pure‐culture incubations of A. flavus on live never‐dried cotton fiber from unopened bolls. Evidence indicated it is caused by interaction between kojic acid from the fungus and peroxidase from the fiber. The fluorescence in field‐grown lint or seed‐fuzz is often accompanied by variable but generally high levels of A. flavus‐produced aflatoxins in the seeds bearing such fiber; presence of the fluorescence may be used as a presumptive test for aflatoxins. A 1968 report from Beltsville showed that the BGY fluorescence can also be generated by A. flavus in pure culture on live milk‐stage corn (Zea mays L.) kernels. Others later observed it in corn in the field and used it in corn‐aflatoxin investigations. A rapid presumptive test for aflatoxins in commercial corn, based on the BGY fluorescence, has been extensively used. Aspergillus flavus field infection and the BGY fluorescence in cotton and corn are influenced by the semithermophillic, semixerophytic, and wound‐parasitic characteristics of the fungus.
Nutrient Cycling in an Agricultural Watershed: I. Phreatic Movement
Authors: Lowrance R. Richard , Todd Robert L. , Asmussen Loris E.
Published: July 2010

Much of the runoff from agricultural fields in the southeastern Coastal Plain is carried to a stream channel system in a shallow phreatic aquifer. This subsurface runoff often passes through a band of riparian forest before becoming streamflow. It is hypothesized that the riparian ecosystem acts as a nutrient sink and reduces the concentrations and loads of nutrients in the shallow aquifer before the nutrients reach the stream channel. Concentrations and loads (kg/m2) of NO3‐N, NH4‐N, organic N, dissolved molybdate‐reactive P1 total P, Ca, Mg, K, Cl, and SO4‐S were measured in shallow phreatic wells at 37 locations on an agricultural watershed near Tifton, Ga. Total water volume moving off the watershed in subsurface flow was < 1% of streamflow with corresponding small amounts of nutrients. Nitrate‐N, Ca, and Mg had significantly higher concentrations in field wells than in forest or streamside wells. Concentrations of Cl were not reduced as water moved from field to forest. Processes within the riparian zone apparently converted primarily inorganic N from fields (76% NO3‐N, 6% NH4‐N, 18% organic N) into primarily organic N in streamside wells (10% NO3‐N, 14% NH4‐N, and 76% organic N). Concentration differences between field and forest wells indicated the riparian forest's ability to act as a sink for NO3‐N, Ca, Mg, K, and SO4‐S. Due to their role as nutrient sinks, riparian forests are important in maintaining stream water quality on agricultural watersheds.
Dissipation of Picloram in Storm Runoff
Authors: Mayeux H. S. , Richardson C. W. , Bovey R. W. , Burnett Earl , Merkle M. G. , Meyer R. E.
Published: July 2010

The extent of progressive decrease in concentration of the herbicide picloram (4‐amino‐3,5,6‐trichloropicolinic acid) in intermittent streamflow was determined during runoff‐producing storms. Maximum concentrations of picloram were 48 and 250 mg/m3 in initial runoff water leaving a sprayed 8‐ha area in 1978 and 1979. Concentration decreased with distance from the treated area in proportion to the size of adjacent, untreated watershed subunits, which contributed runoff water to streamflow. Picloram concentrations usually decreased with each successive runoff event; an exception occurred when unusually large quantities of runoff (8.7 cm) diluted concentrations to levels less than those observed in the succeeding event (1.4 cm runoff). About 6% of the applied picloram left the treated area during a period of 1 month when conditions were especially conducive to transport of the herbicice in surface runoff water.

Rapid dilution of picloram was observed after direct introduction of the herbicide near the upper end of a larger stream during rising stage of flow. Maximum concentrations at 90, 1170, and 5400 m downstream from the point of introduction of 1270 g of picloram were 13 720, 470, and 5 mg/m3, respectively. The calculated quantity of picloram which was detected at the 5400‐m sampling point in streamflow was only 0.13% of that introduced. Mixing of water during streamflow and additions of uncontaminated water along the channel apparently reduced picloram concentration to below that detectable by gas chromatography.
Effect of Composted Municipal Sewage Sludge on Growth and Elemental Composition on White Pine and Hybrid Poplar
Authors: Mc Intosh M. S. , Foss J. E. , Wolf D. C. , Brandt K. R. , Darmody R.
Published: July 2010

A field study was conducted to determine the benefits of land application of composted municipal sewage sludge to white pine (Pinus strobus L.) and hybrid poplar (Populus deltoides spp., P. angulata × P. trichocarpa) growth. Composted municipal sewage sludge was disked into a Chester silt loam (Typic Hapludult—fine loamy, mixed, mesic) at rates of 0, 150, and 300 dry Mg/ha. White pine seedlings and hybrid poplar cuttings were grown for 3 y on the plots which had been seeded with ‘Kentucky 31’ tall fescue (Festuca arundinacea Schreb.).

White pine growth was not affected by the compost treatments. Poplar growth, however, increased as a result of the compost application. After 3 y, the average hybrid poplar heights were 233, 443, and 483 cm for the 0, 150, and 300 Mg/ha treatments, respectively. The height differences between the control and the compost‐amended plots were due to a faster growth rate and a longer growth period of the trees on the compost‐amended plots. Hybrid poplars grown on the compost‐amended soil had higher concentrations of N and K and a lower concentration of Zn in the leaves than the control. No consistent differences in elemental composition of the white pine needles were apparent.
The Effect of Chloride on the Availability of Cadmium
Authors: Bingham F. T. , Sposito Garrison , Strong J. E.
Published: July 2010

Cadmium complexes readily with chloride and sulfate; hence, increases in soil salinity may influence its availability. To evaluate the effect of chlorinity, a major component of soil salinity, the following study was undertaken. A greenhouse experiment was conducted with Swiss chard (Beta vulgaris Cicla) as the biological indicator of available Cd in soil at pH 4.0 and pH 7.0 and treated with three levels of Cd(NO3)2 combined with five levels of CaCl2. The soil solution was analyzed for cations and anions; these analyses were used as input data to chemically speciate Cd in the soil solution. Under these treatments, the total concentration of Cd in the soil solution, CdT, was found to exist principally as Cd2+ and CdCl+. Multiple regression analysis of leaf Cd data in relation to the concentration of CdT, Cd2+, and CdCl+ showed leaf Cd to be primarily a function of the Cd2+ concentration.
The Effect of Four Terrestrial Herbicides on the Productivity of Artificial Stream Algal Communities
Authors: Kosinski Robert J. , Merkle Morris G.
Published: July 2010

Artificial streams containing algal communities derived from a spring and an agriculturally impacted stream were used to assess the effect of 0.1, 1, and 10 mg kg−1 atrazine [2‐chloro‐4‐(ethylamino)‐6‐(isopropylamino)‐s‐triazine], trifluralin (α,α,α‐trifluoro‐2,6‐dinitro‐N,N‐dipropyl‐p‐toluidine), MSMA (monosodium methanearsonate), and paraquat (1,1′‐dimethyl‐4,4′‐bipyridylium cation) on the productivity (photosynthesis and respiration) of stream algae. The importance of induced resistance to the herbicides was evaluated by comparing the responses of the spring and stream algae and by determining if allowing the streams to be colonized for 3 weeks in the presence of 0.01 mg kg−1 of the herbicide under test would modify response by selecting for a more resistant flora. Productivity was measured by open‐water oxygen methods for 3 weeks before and 3 weeks after herbicide injection. The communities derived from both the spring and the stream were dominated by diatoms, and responded similarly to trifluralin, atrazine, and MSMA, but had divergent responses to paraquat. Trifluralin had no effect on productivity. Photosynthesis was significantly depressed by 1 and 10 mg kg−1 atrazine and by 10 mg kg−1 MSMA, and there were indications of a slight inhibition by 0.01 mg kg−1 atrazine. Paraquat at 10 mg kg−1 had little effect on the spring‐derived communities but caused severe inhibition of the stream‐derived algae. There was little evidence that exposure to 0.01 mg kg−1 herbicide during colonization modified the response of the algae to any of the herbicides.
Algal Availability of Phosphorus in Suspended Stream Sediments of Varying Particle Size
Authors: Dorich R. A. , Nelson D. W. , Sommers L. E.
Published: July 2010

The availability of sediment P to algae was evaluated in several water stable aggregate‐size fractions of suspended stream sediments collected from an agricultural watershed in northeastern Indiana. Sediments were collected during a storm event, separated into the <2, 2 to 20, 20 to 53, 53 to 212, and > 212 µm size fractions, sterilized by γ irradiation, and incubated for 2 weeks with algae. Algal‐available P (Paa) was determined by measuring decreases in the NaOH‐ and HCl‐extractable inorganic P (Pi) fractions in sediment during the incubation period. The initial concentrations of P in the NaOH‐ and HCl‐extractable Pi fractions were not related to aggregate size. All aggregate‐size fractions had similar Paa concentrations. Nearly equal proportions of sediment Pi (avg 79%) and total P (avg 43%) in aggregate fractions were available to algae, possibly resulting from the similar distribution of primary particle sizes in all aggregate‐size fractions. More than 93% of Paa originated in the NaOH‐extractable P fraction. Samples that were affected by septic effluents tended to be higher in certain sediment P parameters (e.g., NaOH‐extractable Pi, total Pi, total P, and Paa concentrations) than samples containing suspended sediment derived from cropland. This study suggests that runoff models may not need to account for the detachment and transport of aggregate‐size classes to predict the movement of algal‐available P from cropland to surface waters.
The Influence of Mount St. Helens Ash on Wheat Growth and Phosphorus, Sulfur, Calcium, and Magnesium Uptake
Authors: Mahler R. L. , Mc Dole R. E. , Fredrickson M. K.
Published: July 2010

Concern has been expressed that large amounts of volcanic ash from the 18 May 1980 eruption of Mount St. Helens may have created potential nutrition problems associated with wheat (Triticum aestivum L.) production in eastern Washington and northern Idaho to the extent that adjustments need to be made in soil test correlation data. The objectives of this study were to: (i) determine the effect of varying amounts of volcanic ash, either mixed into or placed on the surface of eight different agronomic soils of northern Idaho on total biomass production of wheat under greenhouse conditions, and (ii) to determine the effect of various soil‐ash mixtures on the nutrient concentration and total uptake of P, S, Ca, and Mg by wheat.

Wheat was grown in eight different northern Idaho soils amended with differing levels of volcanic ash (0, 20, 35, 50, and 75%) in the greenhouse. Fertilizer N, P, and S were added to all treatments. Total plant biomass and P, S, Ca, and Mg concentrations and uptake were measured.

Increasing amounts of volcanic ash gave no consistent effects on total wheat biomass. Based on biomass yields, soils were placed into four basic categories: (i) those where increasing levels of ash depressed plant growth, (ii) those where increasing ash levels stimulated biomass production, (iii) those where biomass yields were greatest with moderate levels of ash, and (iv) those where biomass yields were mixed.

Plant S and P concentrations increased with increasing levels of ash for most soils. The ash did not fix appreciable amounts of P and increased plant‐available S. The ash also enhanced Ca and Mg uptake by plants. There is no evidence to suggest that high levels of ash (700 000 kg/ha) inhibit wheat biomass production. Consequently, there is no need for adjustments in soil test calibration data presently used for fertilizer recommendations for wheat.
Factors Affecting Phosphorus Losses from Cultivated Organic Soils
Authors: Cogger Craig , Duxbury John M.
Published: July 2010

Leaching losses of P from organic soils can have a marked effect on water quality. Factors affecting leaching loss of P from cultivated organic soils in western New York State (Carlisle and Palms series) and ways to reduce these losses were investigated. The behavior of P in organic soils from eight sites with annual leaching losses ranging from < 1 to > 30 kg ha−1 y−1 was compared. Inorganic, organic, and total P; P extracted by soil test procedures; percent mineral matter; depth of organic horizons; leaching and adsorption of P; release of P during incubation; and total extractable Al and Fe were compared. A P balance was estimated using field and laboratory data, and cropping and fertilization history. Aluminum, iron, and adsorption equilibria were the best predictors of field leaching losses from these soils. While P loss from these soils is controlled by adsorption reactions, the best way to reduce the loss is through fertilizer management.
Field Performance of Conventional and Alternative Septic Systems in Wet Soils
Authors: Cogger C. G. , Carlile B. L.
Published: July 2010

An 18‐month field evaluation of 15 conventional and alternative septic systems was conducted to determine their effectiveness in soils with high water tables. The alternative designs included four low‐pressure pipe (LPP) systems, two soil replacement systems, and two pressure‐dosed mounds. Water tables were measured and groundwater samples collected monthly from shallow wells placed around each system. The water samples were analyzed for NO3−‐N, NH4+‐N, total Kjeldahl N, total P, and fecal coliform bacteria.

All but one of the systems installed beneath the natural soil surface were saturated with groundwater for at least part of the year. Effluent treatment was poorest around systems that were continuously saturated with groundwater, with average levels of 7.3 mg/L NH4+‐N, 1.0 mg/L NO3−‐N, and 1700 fecal coliform most probable number (MPN)/L found in the groundwater in wells 1.5 m from these systems. Systems that were only seasonally saturated generally performed better, with average levels of 2.3 mg/L NH4+‐N, 2.0 mg/L NO3−‐N, and 560 fecal coliform MPN/L in the groundwater. Mean P levels in the groundwater exceeded 1 mg/L around six of the systems. The highest concentrations were associated with the most heavily loaded systems. Levels of all contaminants decreased with distance from the source. The greatest amount of lateral transport occurred when continuous saturation was accompanied by a steep groundwater gradient.

Improved treatment was obtained using the LPP alternative, provided site and soil conditions were acceptable. Soil replacement systems did not improve treatment, while one mound failed due to overloading and abuse.
Shallow Groundwater Quality Beneath an Intensive Multiple‐Cropping System using Center Pivot Irrigation
Authors: Hubbard R. K. , Asmussen L. E. , Allison H. D.
Published: July 2010

A study was conducted to compare shallow groundwater NO3‐N concentrations under intensive multiple cropping systems with those from under nearby nonagricultural sites. The intensive multiple cropping systems involved center pivot irrigation and sprinkler‐applied fertilizer. The study was conducted on a sandy Coastal Plain soil by weekly measurement and sampling of observation wells located under a center pivot area and at two forest sites. Nitrate‐N concentrations under the center pivot area ranged from < 1 mg/L to about 133 mg/L, with a mean of 20 mg/L (n = 360, SD = 19.5). In contrast, samples from the forest sites had NO3‐N concentrations ranging from < 0.1 mg/L to just over 1 mg/L. Mean NO3‐N concentrations under the center pivot area were found to vary seasonally according to cropping and hydrologic patterns such that the mean values for March–May, June–August, September–November, and December–February were 7, 21, 27, and 21 mg/L, respectively. The lower value for March–May indicated that winter rains leached most of the root zone NO3‐N beneath the wells by March, and that there was a 2 to 3 month lag between spring‐applied N and its appearance in shallow groundwater. The study raises concern about shallow groundwater quality under intense multiple cropping systems on sandy soils. Although studies in this physiographic area of the Coastal Plain have shown that relatively impermeable subsoil horizons cause shallow groundwater to flow laterally to the larger drainage networks, and that alluvial forests then remove most of the N, the results of this study imply that groundwater NO3‐N contamination could be a problem in other physiographic areas having sandy soils lacking such subsoil horizons.
Reduction of Radiostrontium Mobility in Acid Soils by Carbonate Treatment
Authors: Browman M. G. , Spalding B. P.
Published: July 2010

Development of chemical treatments to immobilize 90Sr in soil to prevent its leaching from radioactive waste disposed in shallow land burial sites is highly desirable. Six in situ carbonate‐precipitating treatments, varying the amounts of carbonate, alkaline earth cation (Ca or Ba as chlorides), and order of addition were examined for their ability to immobilize radiostrontium in laboratory soil columns. The Na2CO3‐followed by CaCl2‐treatment was most consistently successful at reducing the teachability of radiostrontium by 0.05M CaCl2 from three low organic matter‐acid soils, immobilizing as much as 53% of added radiostrontium. For the high organic matter‐slightly acid soil, Na2CO3 alone, without supplemental Ca or Ba, resulted in the best immobilization (39%); dissolution of soil organic matter and the alkalinity‐induced aggregate dispersion probably interfered with CaCO3 and/or BaCO3 precipitation. Success of the treatments is based primarily on their ability to generate, in situ, Ca(Sr,Mg)CO3 or Ba(Ca,Mg,Sr)CO3 precipitates that exchange radiostrontium very slowly with eluting Ca ions. Allied tests with 137Cs, which is commonly codisposed with 90Sr, indicated that the treatments described did not interfere with the natural tendency of the selected soils to fix 137Cs strongly.
Forms of Phosphorus in Soil Receiving Cattle Feedlot Waste
Authors: Sharpley A. N. , Smith S. J. , Stewart B. A. , Mathers A. C.
Published: July 2010

Cattle feedlot waste (FLW) was applied (176 to 1614 Mg ha−1) to irrigated continuous‐grain sorghum [Sorghum bicolor (L.) Moench] grown on Pullman clay loam (Torrertic Paleustolls) over an 8‐y period. The FLW applications increased the total, inorganic, organic, and available P content and decreased the P sorption index of surface soil (0–30 cm). Amounts of P in the surface soil were highly correlated with the total amount of FLW‐P applied and time since the last application. The proportion of total P as inorganic P increased (34 to 71%) with larger FLW applications. Increases in the amounts of surface soil inorganic and organic P with FLW application were due mainly to increases in labile fractions of these P forms. When FLW applications were stopped, however, soil organic P contents decreased to pretreatment levels more rapidly than inorganic P contents as a result of labile organic P mineralization. Increased P contents of surface soil following FLW applications will increase the potential for soluble and sediment‐bound P to be transported in runoff.
Uptake and Photosynthetic Inhibition by Atrazine and its Degradation Products on Four Species of Submerged Vascular Plants
Authors: Jones T. W. , Winchell L.
Published: July 2010

The photosynthetic inhibitory effect of atrazine (2‐chloro‐4‐ethylamino‐6‐isopropyl amino‐1,3,5‐triazine) and three of its major metabolites (deethylated, deisopropylated, and hydroxyatrazine) were determined for four species of submerged macrophytes: Potamogeton perfoliatus L., Ruppia maritima L., Myriophyllum spicatum L., and Zannichellia palustris L. The four species showed a similar response to varied dosages of the parent atrazine compound with an average I1 (concentration at which photosynthesis is inhibited by 1%) for the four species of 20 µg/L and an average I50 (concentration at which photosynthesis is inhibited by 50%) for the four species of 95 µg/L. The three major degradation metabolites of atrazine produced varying degrees of photosynthetic inhibition in the four species, but generally the order of toxicity was deethylated > deisopropylated > hydroxyatrazine with hydroxyatrazine causing an apparent stimulation of photosynthesis in several species. Of four species tested, Myriophyllum spicatum L. was the most resistant to atrazine and its metabolites. The magnitude of the actual uptake of the compounds [µg compound/grams dry wt (gdw) plant] by the plants correlated closely with the photosynthetic inhibitory response, i.e., at the same concentration the uptake of atrazine > deethylated > deisopropylated > hydroxyatrazine. Considering that an extremely high environmental concentration (0.5 mg/L) of deethylated atrazine for an estuary only produced a photosynthetic inhibition of from 20 to 40% in four major species of submerged macrophytes, it is concluded that the degradation products of atrazine tested did not play a major role in the disappearance of the submerged vascular plants from the Chesapeake Bay.
Effects of By‐Product Sulfuric Acid on Phyto Availability of Nutrients in Irrigated Calcareous, Saline‐Sodic Soils
Authors: Cates Richard L. , Haby V. A. , Skogley E. O. , Ferguson Hayden
Published: July 2010

Sulfuric acid (H2SO4) is produced during the SO2 scrubbing process at Cu smelters, and “spent” H2SO4 is a waste product from oil refineries. A 2‐year field study was conducted on two irrigated soils high in salts and Na in southcentral Montana to evaluate the effectiveness of H2SO4 for improving nutrient availability and growth of barley (Hordeum vulgare). Treatments included several rates of smelter acid, and comparisons with gypsum (CaSO4·2H2O), spent acid, and feedlot cattle manure in combination with smelter acid. Levels of P, Fe, Zn, Cu, and Mn were measured in the soil, and plant uptake of these elements plus N, K, Ca, Mg, and Na were determined for the second‐year harvest. Sodium adsorption ratio (SAR) was measured in soil extract from the 0‐ to 5‐cm layer at harvest.

Sulfuric acid was an effective amendment for improving soil nutrient availability, barley dry‐matter yield, nutrient uptake, and for reducing SAR and plant uptake of Na. Both smelter acid and spent acid were similar in their effects. Equivalent rates of gypsum and H2SO4 compared in this research were similar for increasing soil Zn, Cu, and Mn availability and for increasing nutrient uptake and barley yield. Sulfuric acid, but not gypsum, increased available soil P and Fe levels.

Sulfuric acid used in combination with manure provided a substantial additional increase in available soil P, Zn, and Mn over acid used alone. The manure‐plus‐acid treatment raised available P in the surface 20 cm of soil from an initial level of 5 mg/kg to a level adequate for good crop growth (ca. 24 mg/kg). Manure plus H2SO4 produced the highest barley yield and nutrient uptake.
Effect of Small‐Scale Composting of Sewage Sludge on Heavy Metal Availability to Plants
Authors: Simeoni L. A. , Barbarick K. A. , Sabey B. R.
Published: July 2010

The effect of small‐scale composting of sewage sludge on heavy metal availability to plants was investigated. Sand‐bed dried, anaerobically digested sewage sludge was mixed with wood chips in a 1:3 volumetric ratio, placed in a 1.4‐m3 box, and amended with sucrose as an available C source. The mixture was composted for about 90 d. A greenhouse study was conducted to evaluate the differences in sludge due to composting. Lettuce (Lactuca sativa) and oats (Avena sativa) were grown in pots containing composted and uncomposted sludge additions at rates equivalent to 0, 60, 120, and 240 Mg/ha to an acid Redfeather loamy sand (Lithic Cryoboralfs) and a neutral Nunn clay loam (Aridic Argiustolls). After 7 weeks, dry‐matter yields were measured and soil and plant samples were analyzed for total content of Cd, Cu, and Zn. Determinations were also made of soil pH, electrical conductivity (EC), and cation exchange capacity (CEC). An organic matter fractionation was carried out on both sludges to determine changes in organic matter and metal distribution brought about by composting.

Additions of compost produced greater yields of both species than additions of sludge due to the lower soluble salt content and Zn availability of the compost. The higher application rates of compost maintained a higher pH on the loamy sand, which possibly decreased Cd and Zn availability to plants. Leaching of soluble Cu complexed during composting might have contributed to a 40% decrease in sludge Cu content, yet no change was noted in Cu availability to crops. Composting increased the humic acid, decreased the β‐humus, and changed Cu and Cd distribution in sludge organic matter.
Biological Immobilization of Zinc and Manganese in Soil
Authors: Zamani B. , Knezek B. D. , Dazzo F. B.
Published: July 2010

A soil perfusion system was used to measure Zn (as Zn2+) immobilization by soil microorganisms in Rubicon sand (Entic Haplorthods, pH 5.9). A 240‐µM Zn solution (320 mL) was continuously perfused through 25 g of gamma‐irradiated (sterilized) or biologically active soil. At steady‐state, approximately 75.0% of the perfusate Zn became bound to the soil column by chemical and physical mechanisms under sterile conditions. The introduction of soil microorganisms and a source of C and energy to the sterile soil column resulted in an additional 20.5% reduction of Zn in the soil perfusate (significant difference at the 99% level) to a new steady‐state level of 10.8 µM after a 72‐hr period. Further perfusion did not remove additional Zn. The nutrient amendment alone did not contribute any significant immobilization of Zn. Thus, under conditions that are conducive to rapid growth, zymogenous soil microorganisms could significantly immobilize and reduce the level of the mobile Zn to a level below that attainable by chemical and physical factors in the soil alone. In contrast with results in Rubicon sand, microbial immobilization in finer‐textured soils (Brookston clay loam—Typic Argiaquolls, pH 7.5) and (Houghton muck soil—Typic Medisaprist, pH 6.0) was not detected. Biological immobilization of Mn in Rubicon sand was also highest when a combination of microbes and nutrients were added. With the use of the soil perfusion system, it is possible to quantitate the contribution of microorganisms to immobilization of Zn and Mn in Rubicon sand receiving utilizable organic materials.