bluuebunny/crossref_metadata_2025_split huggingface dataset:
Responses to Iron Limitation inHordeum vulgareL. as Affected by the Atmospheric CO2Concentration
Authors: Haase S. , Rothe A. , Kania A. , Wasaki J. , Römheld V. , Engels C. , Kandeler E. , Neumann G. 
Published: May 2008

AbstractElevated atmospheric CO2treatments stimulated biomass production in Fe‐sufficient and Fe‐deficient barley plants, both in hydroponics and in soil culture. Root/shoot biomass ratio was increased in severely Fe‐deficient plants grown in hydroponics but not under moderate Fe limitation in soil culture. Significantly increased biomass production in high CO2treatments, even under severe Fe deficiency in hydroponic culture, indicates an improved internal Fe utilization. Iron deficiency‐induced secretion of PS in 0.5 to 2.5 cm sub‐apical root zones was increased by 74% in response to elevated CO2treatments of barley plants in hydroponics but no PS were detectable in root exudates collected from soil‐grown plants. This may be attributed to suppression of PS release by internal Fe concentrations above the critical level for Fe deficiency, determined at final harvest for soil‐grown barley plants, even without additional Fe supply. However, extremely low concentrations of easily plant‐available Fe in the investigated soil and low Fe seed reserves suggest a contribution of PS‐mediated Fe mobilization from sparingly soluble Fe sources to Fe acquisition of the soil‐grown barley plants during the preceding culture period. Higher Fe contents in shoots (+52%) of plants grown in soil culture without Fe supply under elevated atmospheric CO2concentrations may indicate an increased efficiency for Fe acquisition. No significant influence on diversity and function of rhizosphere‐bacterial communities was detectable in the outer rhizosphere soil (0–3 mm distance from the root surface) by DGGE of 16S rRNA gene fragments and analysis of marker enzyme activities for C‐, N‐, and P‐cycles.
Effect of Liquid Municipal Biosolid Application Method on Tile and Ground Water Quality
Authors: Lapen D. R. , Topp E. , Edwards M. , Sabourin L. , Curnoe W. , Gottschall N. , Bolton P. , Rahman S. , Ball‐Coelho B. , Payne M. , Kleywegt S. , McLaughlin N. 
Published: May 2008

AbstractThis study examined bacteria and nutrient quality in tile drainage and shallow ground water resulting from a fall land application of liquid municipal biosolids (LMB), at field application rates of 93,500 L ha−1, to silt‐clay loam agricultural field plots using two different land application approaches. The land application methods were a one‐pass AerWay SSD approach (A), and surface spreading plus subsequent incorporation (SS). For both treatments, it took between 3 and 39 min for LMB to reach tile drains after land application. The A treatment significantly (p < 0.1) reduced application‐induced LMB contamination of tile drains relative to the SS treatment, as shown by mass loads of total Kjeldahl N (TKN), NH4–N, Total P (TP), PO4–P, E. coli, and Clostridium perfringens. E. coli contamination resulting from application occurred to at least 2.0‐m depth in ground water, but was more notable in ground water immediately beneath tile depth (1.2 m). Treatment ground water concentrations of selected nutrients and bacteria for the study period (∼46 d) at 1.2‐m depth were significantly higher in the treatment plots, relative to control plots. The TKN and TP ground water concentrations at 1.2‐m depth were significantly (p < 0.1) higher for the SS treatment, relative to the A treatment, but there were no significant (p > 0.1) treatment differences for the bacteria. For the macroporous field conditions observed, pre‐tillage by equipment such as the AerWay SSD, will reduce LMB‐induced tile and shallow ground water contamination compared to surface spreading over non‐tilled soil, followed by incorporation.
Transport and Fate of Nitrate at the Ground‐Water/Surface‐Water Interface
Authors: Puckett Larry J. , Zamora Celia , Essaid Hedeff , Wilson John T. , Johnson Henry M. , Brayton Michael J. , Vogel Jason R. 
Published: May 2008

AbstractAlthough numerous studies of hyporheic exchange and denitrification have been conducted in pristine, high‐gradient streams, few studies of this type have been conducted in nutrient‐rich, low‐gradient streams. This is a particularly important subject given the interest in nitrogen (N) inputs to the Gulf of Mexico and other eutrophic aquatic systems. A combination of hydrologic, mineralogical, chemical, dissolved gas, and isotopic data were used to determine the processes controlling transport and fate of NO3− in streambeds at five sites across the USA. Water samples were collected from streambeds at depths ranging from 0.3 to 3 m at three to five points across the stream and in two to five separate transects. Residence times of water ranging from 0.28 to 34.7 d m−1 in the streambeds of N‐rich watersheds played an important role in allowing denitrification to decrease NO3− concentrations. Where potential electron donors were limited and residence times were short, denitrification was limited. Consequently, in spite of reducing conditions at some sites, NO3− was transported into the stream. At two of the five study sites, NO3− in surface water infiltrated the streambeds and concentrations decreased, supporting current models that NO3− would be retained in N‐rich streams. At the other three study sites, hydrogeologic controls limited or prevented infiltration of surface water into the streambed, and ground‐water discharge contributed to NO3− loads. Our results also show that in these low hydrologic‐gradient systems, storm and other high‐flow events can be important factors for increasing surface‐water movement into streambeds.
Water Movement within the Unsaturated Zone in Four Agricultural Areas of the United States
Authors: Fisher Lawrence H. , Healy Richard W. 
Published: May 2008

AbstractMillions of tons of agricultural fertilizer and pesticides are applied annually in the USA. Due to the potential for these chemicals to migrate to groundwater, a study was conducted in 2004 using field data to calculate water budgets, rates of groundwater recharge and times of water travel through the unsaturated zone and to identify factors that influence these phenomena. Precipitation was the only water input at sites in Indiana and Maryland; irrigation accounted for about 80% of total water input at sites in California and Washington. Recharge at the Indiana site (47.5 cm) and at the Maryland site (31.5 cm) were equivalent to 51 and 32%, respectively, of annual precipitation and occurred between growing seasons. Recharge at the California site (42.3 cm) and Washington site (11.9 cm) occurred in response to irrigation events and was about 29 and 13% of total water input, respectively. Average residence time of water in the unsaturated zone, calculated using a piston‐flow approach, ranged from less than 1 yr at the Indiana site to more than 8 yr at the Washington site. Results of bromide tracer tests indicate that at three of the four sites, a fraction of the water applied at land surface may have traveled to the water table in less than 1 yr. The timing and intensity of precipitation and irrigation were the dominant factors controlling recharge, suggesting that the time of the year at which chemicals are applied may be important for chemical transport through the unsaturated zone.
A Comparison of Phosphorus Speciation and Potential Bioavailability in Feed and Feces of Different Dairy Herds Using 31P Nuclear Magnetic Resonance Spectroscopy
Authors: McDowell R. W. , Dou Z. , Toth J. D. , Cade‐Menun B. J. , Kleinman P. J. A. , Soder K. , Saporito L. 
Published: May 2008

AbstractAn experiment was conducted to examine how potential phosphorus (P) bioavailability (inferred from speciation) differs in feed and feces collected in spring from four dairy herds representing different management systems: (i) total confinement with cows fed total mixed ration (TMR), (ii) total confinement with TMR plus P mineral supplement, (iii) a hybrid of confinement with TMR and pastoral grazing, and (iv) predominantly grazing with supplemental grains. A treatment was included that air dried feces to simulate conditions after dung deposition. Wet chemical techniques and solution 31P nuclear magnetic resonance spectroscopy (31P‐NMR) were used to identify P concentrations and compounds present in water (a surrogate for P in overland flow), dilute acid (0.012 M HCl, an estimate of P utilization by cattle), or NaOH‐EDTA (a solution that maximizes the organic P extraction) extracts of feed and feces. In general, P concentration in feces paralleled P in feed. Air drying feces decreased water‐extractable P by 13 to 61% largely due to a decrease in orthophosphate, whereas NaOH‐EDTA–extractable P increased by 18 to 48%. Analysis of dilute HCl was unsuccessful due to orthophosphate precipitation when pH was adjusted to 12 for 31P‐NMR. In water extracts, more P was in bioavailable diester‐P forms, undetectable by colorimetry, than in NaOH‐EDTA extracts. In feed, orthophosphate dominated (46–70%), but myo‐IHP varied with feed (<10% in forage samples but 43% in a TMR sample). The proportion of myo‐IHP decreased in feces compared with feed via mineralization but decreased less in systems with a greater proportion of available P input (e.g., orthophosphate and phospholipids). Feed and drying effect the concentrations and forms of P in feces and their potential impact on soil and water quality. Although bioavailable P in feces from pasture‐based and confined systems can be similar in spring, dung‐P is distributed on a lower kg P ha−1 rate in grazing systems. The best method to mitigate P loss from feces is to decrease P in feed.
Spatial Distributions and Potential Risk Analysis of Total Soil Selenium in Guangdong Province, China
Authors: Zhang H. H. , Wu Z. F. , Yang C. L. , Xia B. , Xu D. R. , Yuan H. X. 
Published: May 2008

AbstractA total of 260 soil profiles were examined to investigate the spatial distribution of total soil selenium (Se) in Guangdong province, China. In the investigated area, the soil Se concentrations follow an approximately lognormal distribution. The soil Se geometric mean concentration of 0.23 mg kg−1 is higher than that of Chinese soils; however, Se concentration varies over the study area. The baseline concentration of 0.13 to 0.41 mg kg−1 indicates that the soil Se concentration is mostly in the range of deficiency to medium level for surface soils in Guangdong province. In A‐, B‐, and C‐horizon, soil Se spatial distribution is correlated with the nature of the parent material, with high Se concentration mainly located in limestone and sandshale areas and low Se concentration associated with purple shale and granite areas. The spatial distribution pattern of soil Se concentrations suggests that potential Se deficiency may be an issue for human health in this province. Moreover, due to soil degradation and erosion, calculated soil Se exported into surrounding waters could reach approximately 23,000 kg yr−1 in the study area.
Field Evaluation of Nitrogen Availability from Fresh and Composted Manure
Authors: Muñoz Gabriela R. , Kelling Keith A. , Rylant Karen E. , Zhu Jun 
Published: May 2008

AbstractPrediction of manure nitrogen availability to crops is key to ensuring adequate production while minimizing potential adverse environmental impacts. This field study estimated first‐year and residual N availability from several manures subjected to various levels of processing, and evaluated the applicability of the presidedress soil N test (PSNT) in fields receiving the different manures using corn (Zea mays L.) as the test crop. Plots received several rates of fresh (FP), dried (DP), or composted (CP) poultry (Gallus gallus domesticus) manure, composted cow (Bos taurus) (CC) manure, ammonium nitrate (AN), or no N. Crop yields and N uptake from plots where CC was applied were undistinguishable from controls in most years, whereas poultry manures significantly increased corn production. Average apparent first‐year N availability, as measured by fertilizer equivalence, was 57, 53, 14, and 4% for FP, DP, CP, and CC respectively. Apparent second‐year N availability, as measured by relative effectiveness, was 18, 19, 12, and 7% for FP, DP, CP, and CC; however, for CC both first‐ and second‐year estimates of apparent N recovery (ANR) could statistically not be separated from the controls. Apparent nitrogen avail‐ability was greater for less processed manures and for CP compared to CC, emphasizing that producers should know the source and level of compost stability when these materials are used as a primary nutrient source. The PSNT successfully (87% correct) identified sites with a critical value of 24 mg kg−1 that were N sufficient across a variety of N amendments from those that would have benefitted from additional N input.
National, Holistic, Watershed‐Scale Approach to Understand the Sources, Transport, and Fate of Agricultural Chemicals
Authors: Capel Paul D. , McCarthy Kathleen A. , Barbash Jack E. 
Published: May 2008

AbstractThis paper is an introduction to the following series of papers that report on in‐depth investigations that have been conducted at five agricultural study areas across the United States in order to gain insights into how environmental processes and agricultural practices interact to determine the transport and fate of agricultural chemicals in the environment. These are the first study areas in an ongoing national study. The study areas were selected, based on the combination of cropping patterns and hydrologic setting, as representative of nationally important agricultural settings to form a basis for extrapolation to unstudied areas. The holistic, watershed‐scale study design that involves multiple environmental compartments and that employs both field observations and simulation modeling is presented. This paper introduces the overall study design and presents an overview of the hydrology of the five study areas.
Tillage, Cropping Systems, and Nitrogen Fertilizer Source Effects on Soil Carbon Sequestration and Fractions
Authors: Sainju Upendra M. , Senwo Zachary N. , Nyakatawa Ermson Z. , Tazisong Irenus A. , Reddy K. Chandra 
Published: May 2008

AbstractQuantification of soil carbon (C) cycling as influenced by management practices is needed for C sequestration and soil quality improvement. We evaluated the 10‐yr effects of tillage, cropping system, and N source on crop residue and soil C fractions at 0‐ to 20‐cm depth in Decatur silt loam (clayey, kaolinitic, thermic, Typic Paleudults) in northern Alabama, USA. Treatments were incomplete factorial combinations of three tillage practices (no‐till [NT], mulch till [MT], and conventional till [CT]), two cropping systems (cotton [Gossypium hirsutum L.]‐cotton‐corn [Zea mays L.] and rye [Secale cereale L.]/cotton‐rye/cotton‐corn), and two N fertilization sources and rates (0 and 100 kg N ha−1 from NH4NO3 and 100 and 200 kg N ha−1 from poultry litter). Carbon fractions were soil organic C (SOC), particulate organic C (POC), microbial biomass C (MBC), and potential C mineralization (PCM). Crop residue varied among treatments and years and total residue from 1997 to 2005 was greater in rye/cotton‐rye/cotton‐corn than in cotton‐cotton‐corn and greater with NH4NO3 than with poultry litter at 100 kg N ha−1 The SOC content at 0 to 20 cm after 10 yr was greater with poultry litter than with NH4NO3 in NT and CT, resulting in a C sequestration rate of 510 kg C ha−1 yr−1 with poultry litter compared with −120 to 147 kg C ha−1 yr−1 with NH4NO3 Poultry litter also increased PCM and MBC compared with NH4NO3 Cropping increased SOC, POC, and PCM compared with fallow in NT. Long‐term poultry litter application or continuous cropping increased soil C storage and microbial biomass and activity compared with inorganic N fertilization or fallow, indicating that these management practices can sequester C, offset atmospheric CO2 levels, and improve soil and environmental quality.
Effects of Soil Phosphorus Status on Environmental Risk Assessment of Glyphosate and Glufosinate‐Ammonium
Authors: Laitinen Pirkko , Siimes Katri , Rämö Sari , Jauhiainen Lauri , Eronen Liisa , Oinonen Seija , Hartikainen Helinä 
Published: May 2008

AbstractThe increased use of herbicides poses a risk to the aquatic environment. Easy and economical methods are needed to identify the fields where specific environment protection measures are needed. Phosphorus (P) and organophosphorus herbicides compete for the same adsorption sites in soil. In this study the relationship between P obtained in routine Finnish agronomic tests (acid ammonium acetate [PAC]) and adsorption of glyphosate and glufosinate‐ammonium was investigated to determine whether PAC values could be used in the risk assessment. The adsorption of glyphosate ((N‐(phosphonomethyl)glycine) and glufosinate‐ammonium (2‐amino‐4‐(hydroxymethylphosphinyl)butanoic acid) was studied in a clay and a sandy loam soil enriched with increasing amounts of P added as potassium dihydrogen phosphate. Desorption was also determined for some P‐enriched soil samples. The adsorption of both herbicides diminished with increasing PAC value. The correlations between Freundlich adsorption coefficients obtained in the adsorption tests and PAC were nonlinear but significant (r > 0.98) in both soils. The exponential models of the relationship between soil PAC values and glyphosate adsorption were found to fit well to an independent Finnish soil data set (P < 0.1 for glyphosate and P < 0.01 for glufosinate‐ammonium). The desorption results showed that glufosinate‐ammonium sorption is not inversely related to soil P status, and the high correlation coefficients obtained in the test of the model were thus artifacts caused by an abnormal concentration of exchangeable potassium in soil. The solved equations are a useful tool in assessing the leaching risks of glyphosate, but their use for glufosinate‐ammonium is questionable.
Controlling the Fate of Roxarsone and Inorganic Arsenic in Poultry Litter
Authors: Makris Konstantinos C. , Salazar Jason , Quazi Shahida , Andra Syam S. , Sarkar Dibyendu , Bach Stephan B. H. , Datta Rupali 
Published: May 2008

AbstractA growing body of literature reports 3‐nitro‐4‐hydroxyphenylarsonic acid (roxarsone) degradation in poultry litter (PL) to the more toxic inorganic arsenic (As). Aluminum‐based drinking‐water treatment residuals (WTR) present a low‐cost amendment technology to reduce As availability in PL, similar to the use of alum to reduce phosphorus availability. Batch experiments investigated the effectiveness of WTR in removing roxarsone and inorganic As species from PL aqueous suspensions. Incubation experiments with WTR‐amended PL evaluated the effects of WTR application rates (2.5–15% by weight) and incubation time (up to 32 d) at two incubation temperatures (23 and 35°C) on As availability in PL. Batch PL aqueous experiments showed the high affinity of As(V), As(III), dimethylarsinic acid (DMA), monomethylarsonic acid (MMA), and roxarsone for the WTR. The 10% WTR amendment rate decreased As availability in PL by half of that of the unamended (no WTR) PL‐incubated samples. The reduction in dissolved As concentrations during incubation of WTR‐amended PL samples was kinetically limited, being complete within 13 d. Parallel reductions in roxarsone, As(V), and DMA concentrations were observed with liquid chromatography–inductively coupled plasma mass spectrometry, whereas As(III) and MMA concentrations were always <5% of dissolved As. Incubation temperature did not significantly (p > 0.05) influence dissolved As concentrations in the WTR‐amended PL. Potential formation of a copper‐containing roxarsone metabolite was considered in PL aqueous suspensions with the aid of electrospray mass spectrometry. Further experiments in the field are necessary to ensure that sorbed As is stable in WTR‐amended PL.
Effect of Land Cover Data on Nitrous Oxide Inventory in Fen Meadows
Authors: Nol Linda , Verburg Peter H. , Heuvelink Gerard B. M. , Molenaar Karin 
Published: May 2008

AbstractLandscape representations based on land cover databases differ significantly from the real landscape. Using a land cover database with high uncertainty as input for emission inventory analyses can cause propagation of systematic and random errors. The objective of this study was to analyze how different land cover representations introduce systematic errors into the results of regional N2O emission inventories. Surface areas of grassland, ditches, and ditch banks were estimated for two polders in the Dutch fen meadow landscape using five land cover representations: four commonly used databases and a detailed field map, which most closely resembles the real landscape. These estimated surface areas were scaled up to the Dutch western fen meadow landscape. Based on the estimated surface areas agricultural N2O emissions were estimated using different inventory techniques. All four common databases overestimated the grassland area when compared to the field map. This caused a considerable overestimation of agricultural N2O emissions, ranging from 9% for more detailed databases to 11% for the coarsest database. The effect of poor land cover representation was larger for an inventory method based on a process model than for inventory methods based on simple emission factors. Although the effect of errors in land cover representations may be small compared to the effect of uncertainties in emission factors, these effects are systematic (i.e., cause bias) and do not cancel out by spatial upscaling. Moreover, bias in land cover representations can be quantified or reduced by careful selection of the land cover database.
Extraction of copper ions using silica gel with chemically modified surface
Authors: Rykowska Iwona , Wasiak Wiesław , Byra Joanna 
Published: May 2008

AbstractThe applicability of silica gels for the application in solid-phase extraction was tested. Silica was modified with ketoimine groups. Surface characteristics of the modified silica were determined by elemental analysis, NMR spectra of solid phases (29Si CP MAS NMR), analysis of pore size distribution of the silica support, and nitrogen adsorption-desorption. Newly proposed sorbents with ketoimine groups were applied in the preconcentration of trace amounts of the Cu (II) ions from lake water, post-industrial water, and demineralized water unburdened back to the lake.
Efficient cyclodehydration of diethylene glycol in Brønsted acidic ionic liquids
Authors: Wang Yuan-Yuan , Li Wei , Dai Li-Yi 
Published: May 2008

AbstractCyclodehydration of diethylene glycol using various Brønsted acidic ionic liquids as dual solvent-catalysts has been studied for the first time. Better results were obtained in the presence of 1-butyl-3-methylimidazolium hydrogen sulfate ([PSmim]HSO4) compared with other Brønsted acidic ionic liquids. Effects of the reaction conditions such as reaction temperature, reaction time and molar ratio of ionic liquid to diethylene glycol have been investigated. High diethylene glycol conversion, 97.0 %, and high 1,4-dioxane selectivity, 89.3 %, were obtained in [PSmim]HSO4 under optimum conditions. Hammett method was used to determine the acidity order of these ionic liquids and the results were consistent with the catalytic activities observed in the cyclodehydration reaction. Utilization of Brønsted acidic ionic liquids as dual solvent-catalysts has some advantages, e.g. high conversion of DEG, easy preparation and reuse of ionic liquids, avoiding toxic catalysts and solvents.