bluuebunny/crossref_metadata_2025_split huggingface dataset:
Efficiency parameters of nitrogen in hog and cattle manure in the second year following application
Authors: Wen Guang , Schoenau Jeff J. , Charles Julian L. , Inanaga Shinobu 
Published: September 2003

AbstractThe efficiency of nitrogen (N) derived from different manures in the years following application must be determined to optimize use of N and reduce impact on the environment. Five N efficiency parameters that were originally developed for commercial inorganic N fertilizers were selected to measure the manure N efficiency in the second year following application of liquid hog and solid cattle manure in semiarid east‐central Saskatchewan, Canada. The manures were applied at two sites (Dixon and Burr) at four rates covering a range from zero to 912 kg N ha–1in 1997. A canola (Brassica napusL.) crop was grown in 1997 followed by a spring wheat (Triticum aestivumL.) in 1998 without fertilization. Tested by the wheat, N utilization efficiency (NUE) was similar between the two manures at either site, but it was higher at Dixon site, where the soil properties were better, than at the Burr site (P < 0.07) with cattle manure. Nitrogen physiological efficiency (NPE) was not affected by either manure source or soil. At the Burr site, N agronomic efficiency (NAE) and N recovery rate (NRR) were all higher with the hog than with the cattle manure (P< 0.08 andP< 0.07, respectively), but N harvest index (NHI) was lower with the hog than with the cattle manure (P< 0.04). The similar trends of the NAE, NRR, and NHI between the hog and cattle manure were also found at the Dixon site. However, the differences in NRR between the hog and cattle manure in the second year was rather small in contrast to the large differences in the year of application. Despite that the wheat crop utilized residual hog and cattle manure N equally efficient in producing grain yield, a higher grain N concentration and a higher NHI with the cattle than with the hog manure revealed different N supply dynamics between the two. Possibly due to the low proportion of ammonium (NH3)‐N in the total N and the high C : N ratio in the cattle manure, mineralization of cattle manure N provided more available N in the later stage of wheat growth than did the hog manure. The N efficiency parameters were useful tools in understanding the impact of residual manure N on wheat production on the Canadian prairies.
Evaluation of soil P‐test values of canton Geneva/Switzerland in relation to P loss risks
Authors: Celardin Fredi 
Published: September 2003

AbstractThe P status of the soils of Geneva is routinely determined by two independent chemical extractions. The P amounts extracted independently by an aqueous solution of ammonium acetate 0.5 M + EDTA 0.02 M (pH 4.65) (1:10 solid weight : solution volume, 60 minutes) and by H2O (1 : 10 solid weight : solution volume, 60 minutes) were assumed to represent mobilizable and mobile phosphorus pools. The best correlations with the data from 1023 crop field soil samples in Geneva canton during the years 1994 to 2000 were obtained by power functions if the data were grouped in two distinct pH ranges:pH 4.6–6.5: (P‐AAE) = 16.436 (P‐H2O) 0.6083; R2 = 0.625; n = 166, pH 6.6–8.6: (P‐AAE) = 25.582 (P‐H2O) 0.6518; R2 = 0.47; n = 857.The derivatives of these functions are representative of apparent P‐buffering power. Environmentally sound threshold values for P‐H2O and P‐AAE are estimated by calculating the change points first of these P‐AAE (quantity) against P‐H2O (intensity) curves and second P‐buffering power against P‐H2O or P‐AAE curves.The change points obtained from the smoothed quantity‐intensity data were:pH 4.6–6.5: P‐H2O = 3.8 mg kg–1 and P‐AAE = 16.436 (3.8)0.6083 = 37.0 mg kg–1; n = 166, pH 6.6–8.6: P‐H2O = 2.5 mg kg–1 and P‐AAE = 25.582 (2.5)0.6518 = 46.5 mg kg–1; n = 857.The change‐points for P‐buffering power curves occurred atpH 4.6–6.5: P‐H2O = 1.3 mg kg–1; P‐AAE = 19.7 mg kg–1; n = 166, pH 6.6–8.6: P‐H2O = 1.3 mg kg–1; P‐AAE = 20.6 mg kg–1; n = 857.The threshold buffering powers were:pH 4.6–6.5: d(P‐AAE)/d(P‐H2O) = 9.998 (P‐H2O) –0.3917 = 9.0, pH 6.6–8.6: d(P‐AAE)/d(P‐H2O) = 16.674 (P‐H2O) –0.3482 = 15.2.These results show that presently only about 25 % of the crop soils of Geneva canton were within these safe limits. The possibility of applying values of this magnitude which are significantly lower than officially recommended reference levels for phosphorus fertilizer recommendations is supported by recent agronomic investigations.
Do different methods used to estimate soil phosphorus availability across Europe give comparable results?
Authors: Neyroud Jean‐A. , Lischer Peter 
Published: September 2003

AbstractEach European country is using its own method for the determination of phosphorus availability to plants, together with an appropriate interpretation scheme of the P status and fertilizer recommendations. In order to compare systems, a soil exchange program was organized: 16 P methods were compared on 135 soils from 12 countries. The amount of extracted P decreased in the order Ptotal > Poxal. > PAL > PMe3 > PBray > PAAEDTA, PDL, PCAL > POlsen > Ppaper strip, PAAAc, PMorgan > PH2O, PCO2, PCaCl2. Isotopically exchangeable P was also measured. A large variability was observed in the results obtained by laboratories using the same method, thus demonstrating the great importance of an identical lab procedure as a prerequisite to any comparison. The traditional correlation/regression approach revealed its limitations when applied to non‐homogeneously distributed data and was replaced by more robust techniques that showed laboratory differential bias and confidence intervals of the log‐transformed values. Even though all the methods reacted in the same way to increasing amounts of added P in several trials, there were wide differences between results obtained with different methods. The interpretation schemes for P status were also compared and revealed that about 50 % of the tested soils were P‐deficient. This observation appears not to be in line with a generally high P fertilization during the last decades in Europe and should lead to a better evaluation of the plant‐available soil phosphorus.
Approaches to calculating P balance at the field‐scale in Europe
Authors: Tunney Hubert , Csath Peter , Ehlert Phillip 
Published: September 2003

AbstractPolicies for mitigating phosphorus (P) loss from agriculture are being developed in a number of European countries and calculation of P balance at farm‐gate or field‐scale is likely to be a part of such policies. The aim of the paper was to study P balance at the field‐scale in 18 countries that participated in the European Union's (EU) European Co‐operation in the Field of Scientific and Technical Research (COST) action on “Quantifying the Agricultural Contribution to Eutrophication (COST 832)”. A questionnaire related to P balance at the field‐scale was sent to representatives in the 18 countries and all replied. The field as a unit is defined differently in the various European agricultural systems. The identification of the inputs and outputs differ among the countries. For example, P losses may or may not be taken into account in balances. Phosphorus balance at the field‐scale is used in all countries in the context of soil analysis and P recommendations for crops and advisory and research purposes, while only a few countries use it for policy purposes (agri‐environmental). There is wide variation in P balances between countries in relation to soil fertility and vulnerability of water to eutrophication from nutrients from agricultural sources. In several eastern European countries, Hungary for example, fertilizer P use has dropped to about one tenth of the levels used in the 1980's. Many of these countries now have a negative P balance. In western European countries, by contrast, although fertilizer P use has decreased in recent years, the average input is higher than the average off take, and soil test phosphorus (STP) values remains high and continue to increase in some areas. Twelve different soil extractants for STP are used in Europe, and their interpretation can hinder direct comparisons. Calculating P balance at the field‐scale involves approximations in estimating inputs and outputs and spatial variations in fertility in individual fields. Accuracy of data and standardization of methods for calculating balances with inputs and outputs will be a challenge for the future development of a sustainable agriculture in Europe.
The conceptual basis for a decision support framework to assess the risk of phosphorus loss at the field scale across Europe
Authors: Heathwaite Louise , Sharpley Andrew , Bechmann Marianne 
Published: September 2003

AbstractWe report a conceptual framework for a simple screening tool to evaluate the vulnerability of different fields in the landscape to phosphorus (P) loss within the European agricultural context. Our work builds on the principles established for the P Index system developed in the United States. We examine the differing needs and criteria for a range of EU member states and EFTA countries and highlight essential and optional criteria for inclusion in the decision support framework depending on their ecoregional characteristics. A framework such as this, meets in principle, the needs of the COST832 Action ‘Quantifying the Agricultural Contribution to Eutrophication’ as it deals with diffuse nutrient sources from agriculture, and aids more targeted use of practical strategies to mitigate nutrient losses to minimise the potential for the eutrophication of receiving waters.
Phosphorus dynamics and export in streams draining micro‐catchments: Development of empirical models
Authors: Kronvang Brian , Bechmann Marianne , Pedersen Morten L. , Flynn Nicola 
Published: September 2003

AbstractAnnual total phosphorus (TP) export data from 108 European micro‐catchments were analyzed against descriptive catchment data on climate (runoff), soil types, catchment size, and land use. The best possible empirical model developed included runoff, proportion of agricultural land and catchment size as explanatory variables but with a low explanation of the variance in the dataset (R2 = 0.37). Improved country specific empirical models could be developed in some cases. The best example was from Norway where an analysis of TP‐export data from 12 predominantly agricultural micro‐catchments revealed a relationship explaining 96 % of the variance in TP‐export. The explanatory variables were in this case soil‐P status (P‐AL), proportion of organic soil, and the export of suspended sediment. Another example is from Denmark where an empirical model was established for the basic annual average TP‐export from 24 catchments with percentage sandy soils, percentage organic soils, runoff, and application of phosphorus in fertilizer and animal manure as explanatory variables (R2 = 0.97).
Incidental phosphorus losses – are they significant and can they be predicted?
Authors: Withers Paul J. A. , Ulén Barbro , Stamm Christian , Bechmann Marianne 
Published: September 2003

AbstractFresh applications of phosphorus (P) may cause ‘incidental’ losses of dissolved and particulate P forms in land runoff when rainfall interacts directly with fertilizers and manures which are spread, or excreted, onto the soil surface. Research indicates that when incidental P losses (IPL) occur, they often make the dominant (50–98 %) contribution to measured P loads in surface and sub‐surface runoff from field plots, with increased risk of eutrophication where P‐enriched runoff is routed directly to the watercourse. Rates of P loss are temporally and spatially very variable (< 1 to 25 % of total P applied) depending on the amount of P applied; the P release properties of the materials applied (% P extractable in water), the timing of storm events after application and the amounts of runoff generated. Large P applications left on the surface of wet, frozen, compacted, and intensively underdrained soils in high rainfall areas are particularly vulnerable to IPL. Concentrations of P in runoff are often greatest during the first storm event following P application, but can remain high for several weeks, or even months after application. Catchment scale impacts are more difficult to quantify due to the effects of dilution with runoff from fields without IPL, and the contributions of P from other sources. Approaches to predicting IPL are discussed and need to be improved in order to assess the contribution of IPL to catchment P loads in river basin management planning. Strategies to control IPL should focus on adoption of more sensitive management practices in fields with a high risk of rapid runoff or preferential flow, and are likely to very effective.
Potential role of phosphate buffering capacity of soils in fertilizer management strategies fitted to environmental goals
Authors: Ehlert Phillip , Morel Christian , Fotyma Mariusz , Destain Jean‐Pierre 
Published: September 2003

AbstractSorption behavior and buffering of phosphorus (P) are important, both from an agricultural and an environmental point of view. The objectives of this study were to investigate: (1) the kinetics of the transfer of P from soil to soil solution and assessing P buffering capacity of soils (PBC), as a function of soil solution P; (2) the effect of PBC on soil P status fitted to environmental targets for water quality; (3) the effect of PBC on crop response. PBC was derived from the non‐linear Q‐I curve describing the time‐dependent relationship between plant‐available reserve of soil P (Q) versus soil solution P (I). The Q‐I curve was determined in soil suspension using sorption and isotopic dilution methods for soil samples from French, Swedish, and Dutch field trials. Soils with low PBC values were more sensitive to the loss of P to the environment, required higher critical value in soil solution P to comply with P demand of maize, and had higher change in soil solution P per unit of P budget. In different soils, both the critical soil solution P for maize and the change in soil solution P per unit of P balance varied inversely with PBC. It is concluded that (1) PBC plays a key role in determining the agronomic and environmental threshold levels of available P content in the soils, and (2) PBC is a prerequisite for the development of more environmentally oriented fertilization recommendation systems.
Risk assessment methodologies for predicting phosphorus losses
Authors: Schoumans Oscar F. , Chardon Wim J. 
Published: September 2003

AbstractRisk assessment parameters are needed to assess the contribution of phosphorus (P) losses from soil to surface water, and the effectiveness of nutrient and land management strategies for the reduction of P loss. These parameters need to take into account the large temporal and spatial variation in P transfer from individual fields arising from (a) changing but predictable factors such as land use, soil P status, P application rates, forms and ways of fertilization and spreading, (b) predictable but inherent factors such as soil type, soil dispersivity, slope and hydrological routing, and (c) unpredictable weather factors such as rainfall amount and intensity. In most situations, water transport is the driving force of P loss from agricultural land to surface water. Therefore, the hydrological pathways determine to a large extent the relevance of these different factors. Over the last decade several soil P tests have been proposed as a first step to link field conditions to risk of P loss. The major reason is that these soil P tests are also meaningful in discussions with farmers. Recently, more complex P loss risk parameters have been derived based on different approaches. However, the scope and purposes of these P loss risk parameters vary remarkably. Finally, there is a need to evaluate the usefulness of new P tests that can be used as an indicator of P loss risk, e.g. in relation to monitoring purposes. The implementation of the EU Water Framework Directive will increase this need.In this paper, the practicable applicability of P parameters for risk assessment is discussed in relation to purpose, scale (from field, farm to catchment), effectiveness, sensibility etc. Furthermore, a conceptual framework for P indicators is presented and evaluated, based on the outcome of the presentations and the discussions in Zurich.
Ethylene Polymerization with Silica‐Supported Nickel‐Diimine Catalyst: Effect of Support and Polymerization Conditions on Catalyst Activity and Polymer Properties
Authors: AlObaidi Fahad , Ye Zhibin , Zhu Shiping 
Published: September 2003

AbstractEthylene was polymerized using both homogeneous and modified methylaluminoxane (MMAO)‐treated silica supported nickel‐diimine catalysts (1,4‐bis(2,6‐diisopropylphenyl) acenaphthene diimine nickel(II) dibromide) in a slurry semibatch reactor. The effects of catalyst support and polymerization conditions (ethylene pressure and reaction temperature) on catalyst activity and polymer properties were systematically investigated. The supported catalyst gave far lower activity than the homogeneous catalyst. The activities of both catalyst systems increased with polymerization temperature with a maximum at 40 °C. Compared with the homogeneous catalyst, the supported catalyst system produced polyethylene with a different microstructure. Due to steric effects, the supported catalyst system exhibited lower chain walking rates than the homogeneous catalyst, producing polymers with less branching content and, thus higher melting points. Depending on polymerization conditions, two active site populations were observed during polymerization using supported catalyst; one population remained fixed on the surface of the support, and the other was extracted from the support, exhibiting the same polymerization behavior as the homogeneous catalyst.DSC thermograms for polyethylene produced with homogeneous and supported catalysts at an ethylene pressure of 50 psig (3.45 · 105 Pa) and reaction temperature 40 °C.magnified imageDSC thermograms for polyethylene produced with homogeneous and supported catalysts at an ethylene pressure of 50 psig (3.45 · 105 Pa) and reaction temperature 40 °C.
Synthesis and Optical Properties of a Copolymer of Tetrafluoro‐ and Dialkoxy‐Substituted Poly(p‐phenylenevinylene) with a High Percentage of Fluorinated Units
Authors: Babudri Francesco , Cardone Antonio , Farinola Gianluca M. , Naso Francesco , Cassano Tiziana , Chiavarone Luca , Tommasi Raffaele 
Published: September 2003

AbstractA copolymer of 2,3,5,6‐tetrafluoro‐1,4‐phenylenevinylene and 2,5‐dioctyloxy‐1,4‐phenylenevinylene [co(TFPV‐DOPV)], containing more than 60% of tetrafluorophenylenevinylene monomeric units, was synthesized by the Stille cross‐coupling reaction. Its linear and nonlinear optical properties were investigated. Linear absorption and photoluminescence measurements performed on thin films and solution indicate interchain migration upon excitation. The Z‐scan technique was used to evaluate the third‐order nonlinear susceptibility at λ = 1064 nm. A very high refractive nonlinearity (n2 = (−10 ± 2) × 10−12 cm2 · W−1) was measured with a value one order of magnitude larger than that of the corresponding dialkoxy‐substituted homopolymer.magnified image
Synthesis of Hyperbranched Poly(phenylene oxide) by Ullmann Polycondensation and Subsequent Utilization as Unimolecular Micelle
Authors: In Insik , Lee Hyosan , Kim Sang Youl 
Published: September 2003

AbstractA new hyperbranched poly(phenylene oxide) was synthesized from a simple AB2 type monomer, 3,5‐dibromophenol, by Ullmann polycondensation. The bromo‐terminated hyperbranched poly(phenylene oxide) was amorphous (Tg = 120 °C), but showed high thermal stability (T5d = 480 °C in nitrogen). The polymer with the degree of branching of 0.61 showed good solubility in organic solvents. The highly branched nature of the polymer effectively disrupted the crystalline characteristics of the linear poly(phenylene oxide) (Tm = 285 °C). When the bromine end groups of the polymer were transformed to lithium carboxylate groups, the resulting polymer became soluble in water. This carboxylate‐terminated hyperbranched poly(phenylene oxide) showed the characteristics of an unimolecular micelle in aqueous solution and behaved as a host for nonpolar organic guest molecules such as 1,4‐diaminoanthraquinone even under the critical micelle concentration of conventional surfactants.DSC and TGA curves of the hyperbranched poly(phenylene oxide) 2.magnified imageDSC and TGA curves of the hyperbranched poly(phenylene oxide) 2.
Microstructure of Metallocene‐Catalyzed Propene/1‐Pentene Copolymers
Authors: Sacchi Maria Carmela , Forlini Fabrizio , Losio Simona , Tritto Incoronata , Wahner Udo M. , Tincul Ioan , Joubert Dawie J. , Sadiku Emmanuel R. 
Published: September 2003

AbstractThe microstructure of propene/1‐pentene copolymers prepared with the metallocene catalysts rac‐Et(Ind)2ZrCl2 and rac‐Me2Si(2‐MeBenz‐[e]Ind)2ZrCl2 was studied by 13C NMR spectroscopy. Both catalysts lead to the formation of random copolymers although rac‐Me2Si(2‐MeBenz‐[e]Ind)2ZrCl2 favors a somewhat higher incorporation of 1‐pentene than rac‐Et(Ind)2ZrCl2. Surprisingly, the presence of 1‐pentene has a significant influence on the stereoregularity of the copolymers formed with rac‐Me2Si(2‐MeBenz‐[e]Ind)2ZrCl2. Propene/1‐pentene copolymers produced with rac‐Et(Ind)2ZrCl2 retained the isotacticity of polypropene and featured only the stereoerror pentads mmmr, mmrr and mrrm typical for enantiomorphic site control. However, propene/1‐pentene copolymers obtained with rac‐Me2Si(2‐MeBenz‐[e]Ind)2ZrCl2 are characterized by a gradual loss of tacticity which is concurrent with an increase in the amount of all irregular pentads. It is proposed that the presence of 1‐pentene can lead to a reversible loss of stereocontrol over a whole sequence of inserted monomer units. Subsequently, more or less atactic blocks are formed besides isotactic blocks.Percentage of 1‐pentene in the copolymer as function of the feed composition for 1‐pentene/propene copolymers prepared with EI and MBI.magnified imagePercentage of 1‐pentene in the copolymer as function of the feed composition for 1‐pentene/propene copolymers prepared with EI and MBI.
Relationship between Architecture and Adhesive Properties of Macromolecular Materials, 1
Authors: Baron Amélie , Cloutet Eric , Cramail Henri , Papon Eric 
Published: September 2003

AbstractThis study deals with the preparation of polyurethane‐graft‐poly(n‐butyl acrylate)s copolymers by polymerization of diphenyl‐methane‐4,4‐di‐isocyanate (MDI) with α,α′‐di‐hydroxyl‐poly(n‐butyl acrylate)s of different sizes as macromonomers. The polyaddition has been studied on the basis of kinetic measurements, and the comb‐like structure of the resulting polymer has been well‐established. Such grafted copolymers display specific adhesive properties in connection with their comb‐like architecture.magnified image