bluuebunny/crossref_metadata_2025_split huggingface dataset:
Design for an Automated Tension Infiltrometer
Authors: Ankeny M. D. , Kaspar T. C. , Horton R. 
Published: July 2010

AbstractAn automated tension infiltrometer useful for a range of water tensions from 0.02 to 0.50 m and for infiltration rates of 1 × 10−8 to 5 × 10−4 m s 1 is described. Infiltration rates are calculated from the change in water height in a Mariotte column. Water height is automatically measured by using the difference in tension between two pressure transducers, one installed at the top, and the other at the bottom, of the Mariotte column. Precision of water height measurement using two transducers (SD = 2.2 mm) is increased as compared with height measurements made with only one transducer (SD = 6.2 mm). With only one transducer, much of the measurement error is due to tension fluctuations or “noise” caused by bubbling in the Mariotte column. The new design also incorporates several features used or suggested by other workers. A bubble tower is used for tension regulation, and interchangeable Mariotte columns of different diameters are used to match column volume with expected cumulative infiltration. Advantages of the new device include (i) quick and accurate tension control at low tensions, (ii) improved measurement precision at low flow rates, and (iii) automatic measurement and data collection, which increases measurement speed and eliminates bubbling‐induced variability.
A Sequential Extraction Procedure with Concentrated Sulfuric Acid and Dilute Base for Soil Organic Phosphorus
Authors: Bowman R. A. 
Published: July 2010

AbstractA total soil organic P (TPo) method that retains the relative ease of the dry combustion method and still preserves essentially all organic P in the extract would be desirable. A sequential extraction procedure for TPo with concentrated sulfuric acid and dilute base was therefore developed to meet these objectives. The method was based on the high efficiency of Po extracted from soils by the heat of solution created by addition of water to concentrated H2SO4. In this step of the procedure, 79% of the total Po was extracted. The acidic soil residue was next treated with NaOH to complete the extraction of Po. The sum of the acid‐ and base‐extractable Po gave a measure of the total soil Po. The method did not hydrolyze or only minimally hydrolyzed Po substrates added to test soils. The proposed procedure was compared with the Mehta extraction method, and with an ignition method developed by Saunders and Williams. In a test of 12 different soils (prairie to highly weathered) the proposed procedure extracted an average of 4% more Po than did the Mehta, and 17% less Po than the Saunders and Williams procedures. The proposed procedure is more rapid than either of the other procedures, and is equally precise. The ease with which the proposed method can be performed as stated, or performed in combination with the high temperature base extraction of the Mehta procedure, makes it ideal for routine laboratory use, especially when the nature of the Po compounds also is being investigated.
Phosphate Sorption by Calcareous Vertisols and Inceptisols of Spain
Authors: Solis P. , Torrent J. 
Published: July 2010

AbstractThe study of phosphate sorption by soils has practical interest but little is known on the quantitative importance of phosphate sorption by Vertisols and the soil properties affecting it. In this study we examined phosphate sorption by 24 samples of calcareous Vertisols and associated Inceptisols of southern Spain. Sorption isotherms were described by the Freundlich equation. The amount of phosphate sorbed at 6 d at 1 mg P L−1 equilibrium concentration was highly correlated with the percentages of citrate‐dithionite‐bicarbonate extractable Fe (Fe4) and clay; regression analysis suggested that the Fe oxides, as estimated by Fed, were the most active sorbents. In contrast calcium carbonate seemed to play a secondary role in sorption. Phosphorus buffer capacity was also highly correlated with the content in Fe oxides (r = 0.79) but less with clay content. Little sorption took place after 6 d for equilibrium concentrations of about 1 mg P L−1. Long‐term sorption was affected by calcium carbonate content; Fe oxides seemed to contribute little to that process. Buffer capacity measured from P quantity and intensity changes produced by cropping was similar in magnitude and weakly correlated with the buffer capacity calculated from sorption isotherms in the laboratory. Thus, sorption curves can provide an estimate of the buffer capacity in desorption by plants for the soils studied.
Copper and Cadmium Effects on Potassium Adsorption and Buffering Capacity
Authors: Yang Jae E. , Skogley Earl O. 
Published: July 2010

AbstractTrace metals have accumulated in many soils from application of mine wastes, sewage sludges, and other residues. Toxic effects of heavy metals on plants growing in contaminated soil have been well documented, but related effects of heavy metals on nutrient availability, e.g., K, are limited. This research was conducted to investigate influences of Cu or Cd added as Cl salts on K adsorption kinetics, K buffering capacity, and relative distribution of K between solution and solid phase. Amsterdam silty clay loam (Typic Haploboroll) was equilibrated with H2O (Soil/H2O = 1:10) containing seven levels of K and three levels of Cu or Cd at 5 and 20 °C for 0.25 to 336 h. The major species of K, Cu, and Cd were K and Cu in the K‐Cu system, and K, Cd, and CdCl in the K‐Cd system as calculated by GEOCHEM. The kinetics of K adsorption was best described by the Elovich equation. Potassium adsorption was rapid, occurring in less than 15 min, followed by a gradual continuous adsorption. The amount of K adsorbed decreased more from Cu than from Cd additions. Reaction rate constants decreased with increasing Cu and Cd. Potassium buffering capacity decreased 20 to 32% and 7 to 20%, respectively, from addition of 400 mg Cu or Cd kg−1 soil. Copper and Cd changed the distribution of K, Ca, and Mg between soil and solution. Soil‐selectivity order for these cations was Ca > Mg > K. Additions of Cu and Cd increased exchange‐site selectivity for K more than that of Mg or Ca, in that order. Potassium‐Ca distribution was influenced more by Cu and Cd than was K‐Mg distribution. Results suggest that trace‐metal contamination of the soil might influence soil K availability by changing K adsorption kinetics, buffering capacity, and distribution.
Mapping Ordinal Data in Soil Survey: A Costa Rican Example
Authors: Bregt A. K. , Stoorvogel J. J. , Bouma J. , Stein A. 
Published: July 2010

AbstractIn most soil surveys, and particularly those carried out in developing countries, the bulk of recorded soil data is on an ordinal measurement scale. This determines the type of statistics and techniques that can be used for data processing. For example, with ordinal data the mode, median, and range can be used as summary statistics. For describing the spatial structure of ordinal data we propose the spatial‐difference‐probability function, which is comparable with the semivariogram. From a soil survey in Costa Rica, three different suitability maps for banana (Musa x paradisiaca L.) were produced according to a qualitative land‐evaluation procedure by interpreting: (i) the 1:200 000 soil map, (ii) the 1:50 000 soil map, and (iii) point data. The quality of these three maps was tested by looking at the reliability, relevance, and presentation of information, using 98 test borings. Reliability was characterized in terms of purity and range. The suitability map based on the 1:200 000 soil map was the most reliable one, with an overall purity of 49%. The suitability map produced by interpolating point data was the most relevant one, as defined in terms of the possibility to correctly identify potential locations for banana plantations from the map. Differences in presentation of information were evaluated by comparing the boundary indices of the different maps. The suitability map based on the 1:50 000 soil map was the most readable one. Map choice should be based on a consideration by the user of the different quality criteria.
Cotton Response to Residual Fertilizer Potassium on Vermiculitic Soil: Organic Matter and Sodium Effects
Authors: Cassman K. G. , Roberts B. A. , Bryant D. C. 
Published: July 2010

AbstractEconomic return from K addition to soils with a large K‐fixation capacity is largely determined by the residual benefit. To quantify the residual benefit on a vermiculitic soil, wheat (Triticum aestivum L.) was grown in 1988 and cotton (Gossypium hirsutum L.) in 1989 and 1990 in treatments that had received previous fertilizer‐K inputs of 0, 360, 720, and 1440 kg ha−1 from 1985 to 1987. Wheat yield and K uptake were not affected by previous K input levels. In contrast, lint yield of cotton with the highest residual‐K rate increased by 240 to 250 kg ha−1 in 1989 and 1990 (a 22–23% increase) compared with the control without previous K addition. In all years, lint yield was closely correlated with solution‐phase K+ in surface soil although a slow K‐fixation reaction decreased this soil K pool by 23% from 1987 to 1990. This reduction occurred despite net inputs of 85 and 130 kg K ha−1 to cotton in 1989 and 1990, respectively, that were uniformly applied as manure or mineral fertilizer‐K main plots over the existing previous K‐rate treatments, which were subplots. Manure application resulted in a significant increase in soil organic C and reduced the slow fixation of K from the labile pool, compared with equivalent K inputs from mineral fertilizer. Use of moderately saline groundwater for irrigation in the drought years of 1989 and 1990 increased extractable Na from 0.07 cmol kg−1 in 1987 to 1.24 cmol kg−1 in 1990. With increased soil Na, there was a shift in the lint yield response to solution‐phase K+ such that the critical level for maximum yield was reduced. These results demonstrated a large cotton yield response to residual fertilizer K on vermiculitic soils, and this residual benefit was greater with organic‐matter addition. Where Na has been leached from the root zone, a moderate increase in soil Na may reduce the total K requirement due to a Na‐K substitution that is known to maintain cotton yields at lower levels of K supply.
Sorption and Desorption Quantity‐Intensity Parameters Related to Plant‐Available Soil Phosphorus
Authors: Raven K. P. , Hossner L. R. 
Published: July 2010

AbstractPhosphorus sorption quantity‐intensity (Q/I) relationships have been used more frequently than desorption to assess the capacity of soils to supply P to plants, although desorption properties would seem more appropriate when studying the soil‐plant system since P release is a key feature. The objective of this study was to compare sorption and desorption Q/I parameters as soil P availability indexes. Five soils with diverse chemical and physical properties were enriched with 0, 25, 50, 75, and 100 mg P kg−1. Phosphorus sorption and desorption data were related to corn (Zea mays L.) growth and P uptake results from a greenhouse experiment. The solution P concentration after a given P addition and the corresponding slope of the Q/I curve or P buffering power were used as the sorption intensity and capacity parameters, respectively. The solution P concentration when no P is desorbed by the sample (Io), the magnitude of slope of the Q/I curve at Io or P buffering power at Io, and the maximum desorbed soil P (Qmax) were used as desorption intensity, capacity, and quantity parameters, respectively. Intensity and capacity factors derived from sorption and desorption Q/I curves were not good indicators of the P supplying capacity of soils, but the Qmax was better related to plant growth and P uptake. These results suggest that a specific quantity parameter gained from P desorption Q/I relationships is more useful and meaningful than any parameter obtained from P sorption curves when evaluating the plant‐available P in soils. No simple relationship existed between capacity parameters obtained from sorption and desorption curves.
Crop Rotation and Tillage Effects on Phosphorus Distribution in the Central Great Plains
Authors: Bowman R. A. , Halvorson A. D. 
Published: July 2010

AbstractThe fate and availability of soil P in the central Great Plains may become less predictable with less tillage and more intensive crop rotations that produce more crop residue and litter than conventional‐till (CT) wheat (Triticum aestivum L.)‐fallow (W‐F). We need to evaluate these new systems relative to new P distribution patterns that may be occurring. We determined P changes in a Weld silt loam soil (fine, montmorillonitic, mesic aridic Paleustoll) in predetermined plots from a 5‐year rotation‐tillage experiment where 45 kg P ha−1 was applied in 1990, and 18 kg P ha−1 was applied to the wheat phase of the rotation thereafter. We determined changes in water‐soluble P, resin‐extractable P, total organic P, bicarbonate‐extractable P, and phosphomonoesterase activity as a function of tillage and cropping intensity in soil from the 0‐ to 5‐cm and 0‐ to 15‐cm depths. Phosphorus concentration in wheat tops at an early stage was also determined to assess soil P availability. Generally, P availability indices increased significantly in the 0‐ to 5‐cm depth with continuous cropping treatments compared with wheat‐fallow treatments. The results suggest that under more intensive cropping systems P recycling through residue and litter could be an important mechanism resulting in additional plant‐available P.
Manure Management in an Irrigated Silage Corn Field: Experiment and Modeling
Authors: Ma Liwang , Shaffer M. J. , Ahuja L. R. , Rojas K. W. , Xu C. , Boyd J. K. , Waskom R. 
Published: July 2010

AbstractOn agricultural lands, animal waste disposal as fertilizer has been practiced since the beginning of agriculture. However, the practice has been an environmental concern in recent years due to over disposal of animal waste in some instances. This study evaluated soil NO3 response to beef‐manure application on a corn (Zea mays L.) field and tested the Root Zone Water Quality Model (RZWQM) for manure management. The experiment site was located in Northeastern Colorado on a silage‐corn field with a history of fertilization with beef manure every fall after corn harvest. To study the residual effect of long‐term manure application, 582 kg ha‐1 of manure‐N was applied to the east side of the field in the Fall of 1993, 1994, and 1995, while the west side received manure in 1993 only. Average silage‐corn yields from the west site were 25.4, 31.9, and 22.5 Mg ha‐1 for 1994, 1995, and 1996, respectively, which were not significantly different from that harvested from the east site (25.1, 30.9, and 24.3 Mg ha‐1, respectively). Average soil NO3 concentrations decreased significantly from 14.9 to 8.5 mg N kg‐1 in the top 30 cm of soil, and from 5.4 to 3.7 mg N kg‐1 in the 30‐ to 60‐cm soil profile after stopping manure application. No significant difference in soil NO3 concentrations between the manured and not‐manured sites was found below 60 cm. Average plant N uptake ranged from 140 to 362 kg N ha‐1 and was not significantly different between the two sites. The RZWQM was calibrated on the basis of the measured silage‐corn yield and plant N uptake, and was then used to predict soil NO3 concentration and total water storage in the soil profile. Generally, the calibrated model provided adequate predictions for both NO3 and soil water content with r2 > 0.83. The model was further used to evaluate alternative scenarios of manure and water management.
Tillage Impacts on Depth Distribution of Total and Particulate Organic Matter in Three Illinois Soils
Authors: Wander M. M. , Bidart M. G. , Aref S. 
Published: July 2010

AbstractThe benefits of no‐tillage (NT) practices to soil organic matter (SOM) are inconsistent in fine‐textured, poorly drained soils. Tillage impacts on SOM were investigated in central Illinois, assuming particulate organic matter (POM) would accumulate where SOM aggraded. Soils were collected in 1994 and 1995 from a trial established in 1985 at Perry and Monmouth (somewhat poorly drained Aquic Argiudoll silt loams), and DeKalb (a poorly drained Typic Haplaquoll silty clay loam). In general, NT practices increased SOM‐C and POM‐C contents 25 and 70% compared with conventional till (CT) at the soil surface (0–5 cm). This was at the expense of C at depth (5–17.5 cm), which decreased by 4 and 18%, respectively. Tillage effects varied among sites. No‐till increased SOM C and POM C more than 30 and 100%, respectively, in the top 5 cm of the two silt loams. In the silty clay loam, NT reduced SOM C 14% in the 5‐ to 17.5‐cm depth and POM C more than 20% in the 5‐ to 30‐cm depth. Bulk density was greater under NT than CT at the DeKalb (0–17.5 cm) and Monmouth sites (0–5 cm). No‐till only increased C and N sequestration, assessed on an equivalent mass basis, at Monmouth. Accumulation of POM in the surface depth of the NT silt loams may have improved soil quality in those erosion‐prone soils. Reduced POM contents in the NT silty clay loam may reflect SOM degradation. The high clay and organic matter content and low bulk density of the DeKalb soil may have contributed to the atypical effect of NT practices on SOM at that site.
Harvesting of Medicinal Plants in the Forest of Central India and its Impact on Quality of Raw Materials: A Case of Nagpur District, India
Authors: Mishra Manish , Kotwal P. C. , Prasad Chandan 
Published: July 2010

Adulteration and substitutions are frequent in raw material trade of medicinal plants. Several studies have been done for a number of important crude drug materials to distinguish the genuine material from adulterant. The efficient way to determine adulteration is through morphological and organoleptic studies. The objective of this study is to find out current harvesting methods, malpractices adopted by various stakeholders and ocular analysis of market samples, impacting quality of raw (dry) produce of selected species in market of Nagpur. In the natural forests Baibirang (Embelia ribes Burm.), Safed musli (mixed tubers of Chlorophytum borivilianum Baker, C. tuberosum Baker.), and Aonla (Emblica officinalis Gaertn.) were collected just after the rains at unripe stage. The ocular observations of the market sample of Aonla, Baibirang fruits, Safed musli tubers indicate that mixing of old and diseased parts of same species and other adulterants is rampant in the local market. Laboratory analysis shows that in one kilogram of market sample, more than 20% raw material was found adulterated in all the selected species except Bach (Acorus calamus L.). Most of the selected plants were found adulterated, both intentionally and unintentionally. Major reasons for poor quality are unripe harvesting, mixing of inferior and cheap plant parts, mis-identification of species, non-availability of plant parts in required quantity, etc. Key words: Adulteration, quality, medicinal plants, harvesting, malpractices. DOI: 10.3126/eco.v16i0.3471ECOPRINT 16: 35-42, 2009
La dimension sociale dans le CECR : pistes pour scénariser, évaluer et valoriser l'apprentissage collaboratif
Authors: Springer Claude 
Published: July 2010

Résumé La « perspective actionnelle » suggère une filiation avec les théories de l'activité, c'est-à-dire une visée socio-culturelle et une visée sociale. Le CECR aborde sans s'attarder cet aspect social en considérant tout locuteur / apprenant dans sa dimension d'acteur social. Dès lors, la « tâche » peut-elle être considérée comme individuelle comme l'approche communicative le laisse entendre ? Comment tenir compte en classe de langues de cette perspective sociale et actionnelle sans retomber dans la tradition de l'apprenant se développant en toute autonomie ? Quelle place accorder, en plus de la compétence de communication, aux compétences dites génériques et transversales qui sont mobilisées nécessairement dans l'action sociale? Comment évaluer et valoriser cette intelligence actionnelle partagée?
A probabilistic indirect adaptive control for systems with input‐dependent noise
Authors: Herzallah Randa 
Published: July 2010

AbstractA probabilistic indirect adaptive controller is proposed for the general nonlinear multivariate class of discrete time system. The proposed probabilistic framework incorporates input–dependent noise prediction parameters in the derivation of the optimal control law. Moreover, because noise can be nonstationary in practice, the proposed adaptive control algorithm provides an elegant method for estimating and tracking the noise. For illustration purposes, the developed method is applied to the affine class of nonlinear multivariate discrete time systems and the desired result is obtained: the optimal control law is determined by solving a cubic equation and the distribution of the tracking error is shown to be Gaussian with zero mean. The efficiency of the proposed scheme is demonstrated numerically through the simulation of an affine nonlinear system. Copyright © 2010 John Wiley & Sons, Ltd.
The use of multiple reference points in risky decision making
Authors: Koop Gregory J. , Johnson Joseph G. 
Published: July 2010

AbstractAmong psychologists and economists, prospect theory continues to be one of the most popular models of decision making. The theory's key property is reference dependence; specifically, how an individual's perception of loss or gain is dependent upon their starting point (i.e., the status quo). Although prospect theory is widely accepted, other authors have sought the inclusion of reference points besides the status quo. Initially these extensions focused on the importance of single reference points such as goals. More recently, authors have explained choice data by including multiple reference points within the value function. Multiple‐reference‐point theories generally assume that many choice situations possess an implicit or explicit goal, or point an individual will strive to obtain, and/or a minimum requirement (i.e., a “lower bound”) above which an individual will strive to stay. In two experiments, we present evidence that individuals can utilize the minimum requirement, status quo, and goal within a single risky decision task. Participants most often chose to maximize their chance of reaching reference points even when that decision was riskier, resulted in lower expected value, resulted in lower expected utility, or ran contrary to the predictions of prospect theory. Furthermore, salience and uncertainty moderated the use of goals and minimum requirements as reference points. Copyright © 2010 John Wiley & Sons, Ltd.
Insulin resistance at the crossroads of metabolic syndrome: Systemic analysis using microarrays
Authors: Kim Eunjung 
Published: July 2010

AbstractRecently, it has been suggested that insulin resistance is a better predictor of metabolic syndrome than obesity. Numerous studies have been conducted to identify insulin resistance susceptibility genes in various model systems. This review focuses on recent findings in microarray analyses, which have indicated that (i) in the liver, genes involved in lipid synthesis and gluconeogenesis are increased in an animal model of insulin resistance that leads into liver steatosis and hyperglycemia; (ii) in adipose tissues, genes involved in fatty acid synthesis and adipogenesis are down‐regulated both in insulin‐resistant humans and in animals; and (iii) in muscle, overall gene expression, including genes involved in fatty acid oxidation and biosynthesis, is either decreased or unresponsive compared to that of insulin‐sensitive control human subjects or animals. Considering the multifaceted effects of insulin resistance in various tissues, aiming at multi‐targets rather than a single target will be a more promising strategy for the prevention or treatment of insulin resistance.