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IMPORTANCE: Implementation of new cancer treatment strategies as recommended by evidence-based guidelines is often slow and suboptimal. OBJECTIVE: To improve the implementation of guideline-based best practices in the Netherlands in pancreatic cancer care and assess the impact on survival. DESIGN, SETTING, AND PARTICIPANTS: This multicenter, stepped-wedge cluster randomized trial compared enhanced implementation of best practices with usual care in consecutive patients with all stages of pancreatic cancer. It took place from May 22, 2018 through July 9, 2020. Data were analyzed from April 1, 2022, through February 1, 2023. It included all patients in the Netherlands with pathologically or clinically diagnosed pancreatic ductal adenocarcinoma. This study reports 1-year follow-up (or shorter in case of deceased patients). INTERVENTION: The 5 best practices included optimal use of perioperative chemotherapy, palliative chemotherapy, pancreatic enzyme replacement therapy (PERT), referral to a dietician, and use of metal stents in patients with biliary obstruction. A 6-week implementation period was completed, in a randomized order, in all 17 Dutch networks for pancreatic cancer care. MAIN OUTCOMES AND MEASURES: The primary outcome was 1-year survival. Secondary outcomes included adherence to best practices and quality of life (European Organisation for Research and Treatment of Cancer [EORTC] global health score). RESULTS: Overall, 5887 patients with pancreatic cancer (median age, 72.0 [IQR, 64.0-79.0] years; 50% female) were enrolled, 2641 before and 2939 after implementation of best practices (307 during wash-in period). One-year survival was 24% vs 23% (hazard ratio, 0.98, 95% CI, 0.88-1.08). There was no difference in the use of neoadjuvant chemotherapy (11% vs 11%), adjuvant chemotherapy (48% vs 51%), and referral to a dietician (59% vs 63%), while the use of palliative chemotherapy (24% vs 30%; odds ratio [OR], 1.38; 95% CI, 1.10-1.74), PERT (34% vs 45%; OR, 1.64; 95% CI, 1.28-2.11), and metal biliary stents increased (74% vs 83%; OR, 1.78; 95% CI, 1.13-2.80). The EORTC global health score did not improve (area under the curve, 43.9 vs 42.8; median difference, −1.09, 95% CI, −3.05 to 0.94). CONCLUSIONS AND RELEVANCE: In this randomized clinical trial, implementation of 5 best practices in pancreatic cancer care did not improve 1-year survival and quality of life. The finding that most patients received no tumor-directed treatment paired with the poor survival highlights the need for more personalized treatment options. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT03513705

Purpose: To assess the usefulness of water drinking test and dark room provocative testing (WDT + DRPT) in current clinical practice by evaluating input parameters from Swept-source Optical Coherence Tomography (SS-OCT) images, and to determine if clinical factors like axial length, central endothelial cell count (CECC) and retinal nerve fibre layer thickness (RNFL) thickness are associated with a positive WDT + DRPT. Methods: SS-OCT examination was performed in consecutive subjects presenting as new patients in the outpatient clinic aged > 40 years. If at least one eye met the inclusion criteria (anterior chamber angles <20° and anterior chamber depth < 2.5 mm on SS-OCT), subjects were included in this study and WDT + DRPT was carried out. The eye with the smallest angle was analysed. The difference in parameters between eyes with a positive (≥8 mmHg) and negative (<8 mmHg) increase in intraocular pressure (IOP) after WDT + DRPT were statistically analysed. Second, the correlation between IOP increase after WDT + DRPT and anterior chamber angle parameters (RNFL thickness, CECC and axial length) was studied. Results: A total of 95 subjects with a mean age of 64 years were included. There was an association between IOP increase after WDT + DRPT and anterior chamber angle characteristics, however this was not of clinical significance. No positive results after WDT + DRPT were found in patients with anterior chamber angles ≥ 20°. Conclusions: The present findings indicate that this combined provocative test has no definite correlative or predictive value in angle closure disease. Further, the test is not useful in predicting early diagnosis or possible CECC or RNFL loss.

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Only limited data is available on the extent and burden of adverse drug reactions (ADRs) to biological therapy in inflammatory bowel disease (IBD) patients in daily practice, especially from a patient's perspective. The aim of this study was to systematically assess patient‐reported ADRs during biological therapy in IBD patients and compare these with healthcare provider (HCP)‐reported ADRs. This multicentre, prospective, event monitoring study enrolled IBD patients on biological therapy. Patients completed bimonthly comprehensive web‐based questionnaires regarding description of biological induced ADRs, follow‐up of previous ADRs and experienced burden of the ADR using a five‐point Likert scale. The relationship between patient‐reported ADRs and biological therapy was assessed. HCP‐reported ADRs were extracted from the electronic healthcare records. In total, 182 patients (female 51%, mean age 42.2 [standard deviation 14.2] years, Crohn's disease 77%) were included and completed 728 questionnaires. At baseline, 60% of patients used infliximab, 30% adalimumab, 9% vedolizumab and 1% ustekinumab. Fifty percent of participants reported at least one ADR with a total of 239 unique ADRs. Fatigue (n= 26) and headache (n= 20) resulted in the highest burden and a correlation in time with the administration of the biological was described in 56% and 85% respectively. Out of 239 ADRs, 115 were considered biological‐related. HCPs reported 119 ADRs. Agreement between patient‐reported ADRs and HCP‐reported ADRs was only 13%. IBD patients often report ADRs during biological therapy. We observed an important significant difference between the type and frequency of patient‐reported ADRs versus HCP‐reported ADRs, leading to an underestimation of more subjective ADRs and patients' ADR‐related burden. Summarise the established knowledge on this subject Adverse drug reactions (ADRs) are severely underreported by healthcare providers (HCP) and do not capture the full spectrum of biological‐related ADRs.Patient self‐reporting may be used to detect ADRs and offers more insight in the patient's perception and experience of an ADR.Data on self‐reporting ADRs in inflammatory bowel disease (IBD) patients is limited. Adverse drug reactions (ADRs) are severely underreported by healthcare providers (HCP) and do not capture the full spectrum of biological‐related ADRs. Patient self‐reporting may be used to detect ADRs and offers more insight in the patient's perception and experience of an ADR. Data on self‐reporting ADRs in inflammatory bowel disease (IBD) patients is limited. What are the significant and/or new findings of this study? IBD patients frequently reported ADRs during biological use (50%) and 48% of these ADRs were considered biological‐related.Fatigue and headache resulted in the highest patient‐reported burden.Patients often reported a correlation in time (44%) for the top six patient‐reported ADRs.There was a significant difference between type and frequency of patient‐reported ADRs and HCP‐reported ADRs. IBD patients frequently reported ADRs during biological use (50%) and 48% of these ADRs were considered biological‐related. Fatigue and headache resulted in the highest patient‐reported burden. Patients often reported a correlation in time (44%) for the top six patient‐reported ADRs. There was a significant difference between type and frequency of patient‐reported ADRs and HCP‐reported ADRs.

It remains unclear whether urgent endoscopic retrograde cholangiopancreatography (ERCP) with biliary sphincterotomy improves the outcome of patients with gallstone pancreatitis without concomitant cholangitis. We did a randomised trial to compare urgent ERCP with sphincterotomy versus conservative treatment in patients with predicted severe acute gallstone pancreatitis.

Due to the unexpected findings of the banned antibiotic chloramphenicol in products of animal origin, feed, and straw, the hypothesis was studied that the drug is naturally present in soil, through production by soil bacteria, and subsequently can be transferred to crops. First, the stability of chloramphenicol in soil was studied. The fate of chloramphenicol highly depends on soil type and showed a half-life of approximately one day in nonsterile topsoil. It was found to be more stable in subsoil and sterile soils. Second, the production of chloramphenicol in soil was studied, and it was confirmed that Streptomyces venezuelaecan produce chloramphenicol at appreciable amounts in nonsterile soil. Third, a transfer study was carried out using wheat and maize grown on three different soils that were weekly exposed to aqueous chloramphenicol solutions at different levels. Chloramphenicol was taken up by crops as determined by chiral liquid chromatography coupled to tandem mass spectrometric analysis, and the levels in crops were found to be bioavailability related. It was concluded that chloramphenicol residues can occur naturally in crops as a result of the production of chloramphenicol by soil bacteria in their natural environment and subsequent uptake by crops.

Post-endoscopic retrograde cholangiopancreatography (ERCP) pancreatitis (PEP) is the most prevalent complication after ERCP with an incidence of 3.5%. PEP severity is classified according to either the consensus criteria or the revised Atlanta criteria. In this international cohort study we investigated which classification is the strongest predictor of PEP-related mortality. We reviewed 13,384 consecutive ERCPs performed between 2012 and 2017 in eight hospitals. We gathered data on all pancreatitis-related adverse events and compared the predictive capabilities of both classifications. Furthermore, we investigated the correlation between the two classifications and identified reasons underlying length of stay. The total sample consisted of 387 patients. The revised Atlanta criteria have a higher sensitivity (100 vs. 55%), specificity (98 vs. 72%) and positive predictive value (58 vs. 5%). There is a significant difference (p?

Background and objective Post-endoscopic retrograde cholangiopancreatography (ERCP) pancreatitis (PEP) is the most prevalent complication after ERCP with an incidence of 3.5%. PEP severity is classified according to either the consensus criteria or the revised Atlanta criteria. In this international cohort study we investigated which classification is the strongest predictor of PEP-related mortality.Methods We reviewed 13,384 consecutive ERCPs performed between 2012 and 2017 in eight hospitals. We gathered data on all pancreatitis-related adverse events and compared the predictive capabilities of both classifications. Furthermore, we investigated the correlation between the two classifications and identified reasons underlying length of stay.Results The total sample consisted of 387 patients. The revised Atlanta criteria have a higher sensitivity (100 vs. 55%), specificity (98 vs. 72%) and positive predictive value (58 vs. 5%). There is a significant difference (p< 0.001) between the two classifications. In 124 patients (32%), the length of stay was influenced by concomitant diseases.Conclusion The revised Atlanta classification is superior in predicting mortality and better reflects PEP severity. This has important implications for researchers, clinicians and patients. For the diagnosis of PEP pancreatitis, the consensus criteria remain the golden standard. However, the revised Atlanta criteria are preferable for defining PEP severity.

Infected necrotising pancreatitis is a potentially lethal disease and an indication for invasive intervention. The surgical step-up approach is the standard treatment. A promising alternative is the endoscopic step-up approach. We compared both approaches to see whether the endoscopic step-up approach was superior to the surgical step-up approach in terms of clinical and economic outcomes.

Despite its effectiveness in treating Crohn's disease, adalimumab is associated with an increased risk of infections and high health-care costs. We aimed to assess clinical outcomes of increased adalimumab dose intervals versus conventional dosing in patients with Crohn's disease in stable remission.

The papers in this issue are based on selected presentations made at a symposium convened to celebrate the 50th anniversary of the founding of the National Sedimentation Laboratory (NSL) of the US Department of Agriculture (USDA), Agricultural Research Service (ARS), located in Oxford, Mississippi. The mission of the NSL is to find solutions to problems associated with soil erosion and sediment delivery from upland areas, erosion and sedimentation in stream channels, the impact of sediment and other agricultural contaminants on the biological well‐being of receiving surface water bodies, and the loss of nutrients and agricultural chemicals from agricultural activities on the landscape. The papers in this issue present a broad overview of current research activities by NSL scientists and their colleagues. Copyright © 2009 John Wiley & Sons, Ltd.

A physical model based on continuum multiphase flow is described to represent saltating transport of grains in shallow overland flows. The two‐phase continuum flow of water and sediment considers coupled StVenant‐type equations. The interactive cumulative effect of grains is incorporated by a dispersive stress term. The mean fluid thrust on the particle in the saltation layer of grains is expressed in terms of a slip velocity. The continuum model leads to the unexpected, but an interesting result is that particle velocity increases with the solid concentration. This increase predicts monotonic behaviour leading to overestimates of particle velocity at higher sediment concentration. To improve the predictions, grain dynamic equations, which incorporate bed collision, are analysed. The analysis leads to an improved model for predicting saltation height. Incorporation of the results in the continuum model yields a velocity‐concentration relationship that is consistent with experimental observations for increasing concentration. Laboratory flume experiments explore the evaluation of various parameters from the measured particle velocities by photonic probes. Copyright © 2009 John Wiley & Sons, Ltd.

Cadmium in soil poses a risk for human health, due to its accumulation in food and feed crops. The extent of accumulation depends strongly on soil type and the degree of pollution. The objective of the present study was to develop a predictive model to estimate human dietary cadmium exposure from soil characteristics. This chain model consists of three basic steps: (i) calculation of plant cadmium levels from soil contamination levels and soil characteristics, (ii) calculation of animal transfer from consumption and contamination levels, and (iii) human exposure from both plant and animal products. Six soil scenarios were assessed, reflecting a specific contaminated region and ranging from 0.5 mg/kg of Cd (pH 4.5) to 2.5 mg/kg of Cd (pH 5.5). Cadmium levels in feed crops and vegetables were estimated with regression and mathematical models. Animal exposure and transfer to cattle kidneys, livers, and meat were calculated using a consumption database and a parameterized linear simulation model. Human exposure was estimated by Monte Carlo simulation, using a consumption database. The median human exposure for the different scenarios ranged from 0.24 to 0.98 μ/kg of body weight per day, which is comparable to results obtained from exposure levels based on observed field contamination data. The study shows that a chain model approach from soil contamination to human exposure, including animal exposure and transfer to animal products, can successfully be applied. The model can be used for fast evaluation of dietary cadmium exposure and the identification of risk areas based on soil conditions.

The depth of the wetting front within a soil sample in infiltration measurements, especially in soils that develop cracks on drying, is difficult to ascertain simply and nondestructively. A technique was developed to determine wetting front locations on prepared soil beds, with a miniature penetrometer probe of the needle type, immediately following a simulated rainfall event. The method involves placing a 0.5‐kg weight atop a miniature penetrometer probe and measuring the penetration depth of the probe relative to a known datum. Five texturally different soils were tested under similar laboratory conditions to evaluate this method. The penetrometer‐based method provided accurate estimates of the wetting front position in laboratory simulated rainfall infiltration studies for clay, silty clay, and sandy clay soils that differed from visually observed depths by <1 mm. For the silt loam soils, however, this method underestimated mean wetting front depths by as much as 4 mm, with a standard deviation of 1.6 mm and 95% confidence limits of ±2.5 mm. The penetrometer method was especially useful for detailed characterization of wetting front depths in soils where wetting was highly variable or irregular (e.g., cracking clay soils).

In areas with intensive animal livestock farming, agricultural soils are enriched with phosphorus (P). These soils exhibit an increased risk for P transfer to the sub-soil and surface water via leaching. Besides the presence of hydrological pathways between a field and surface water, P in soil solution should be studied for evaluating the environmental risk. For this purpose, soil P extraction methods can be used. In this study, we tested the relation between various extraction methods and P in soil solution, simulated by a water extraction at a soil-to-solution ratio of 12 (w/v) using field-moist topsoils sampled from the major Dutch soil types (noncalcareous and calcareous sand and clay, reclaimed peat, and peat). The following methods were used Pw(160 [v/v] water-extractable P), 0.01 MCaCl2(110 [v/v]), FeO-strip, and acid ammonium oxalate-extractable P, Al, and Fe. Phosphorus in the 12 water extracts was mainly present as molybdate-reactive P (MRP). Extraction methods with the highest ability to predict MRP in 12 water extracts across different soil types were CaCl2, Pw, and FeO-strip, the latter two normalized for [Al + Fe]ox. However, for the peat and noncalcareous clay soils, also estimation of molybdate-unreactive P (MUP) is important because MUP dominates in the 12 water extracts of these soils. Thus, an extraction method that only determines MRP will not suffice, and further research is needed on the environmental risk of MUP in soil solution from these soil types. The calcareous sandy soils deviated significantly from the above mentioned relationships. For this soil type, it should be tested whether a single water extraction (e.g., Pw) suffices for determining the environmental risk.

The theory of water movement in high shrink/swell soils has experienced consistent revision since Haines first presented the topic in 1923. Several aspects of the infiltration process in cracking soils have proven to be difficult to measure; seal/crust formation and properties, crack network patterns, preferential flow zones and contributions, and soil moisture determinations within the profile (near crack and near center of prismatic column) to name a few. Here, we used simulated rainstorms, laser measurements of surface elevation, needle‐penetrometer measurements, and mass measurements of infiltrating water over a 206‐ and 145‐d period to examine water movement and cracking patterns in a large sample box filled with a swelling clay soil. Water movement was restricted to the neighborhood of the crack zone, since the formation of a surface seal/crust prohibited infiltration into the surface of the prismatic columns of soil between cracks. Also, the location of cracks was observed to alternate between rainstorms. The alternating crack pattern led to more uniform wetting with depth as time increased and the number of rainstorms increased, thereby reducing the extent of preferential flow.

Soil aggregates low in organic matter and clay contents are generally susceptible to disintegration at low rainfall energies. This study was conducted to evaluate the effectiveness of ferrihydrite (Fe5HO8·4H2O) at stabilizing such aggregates, using five soils with a wide range of physical and chemical properties. The soils were amended with ferrihydrite at rates equivalent to 0, 0.34, 3.36, 16.80, and 33.60 Mg ha−1, packed to a depth of 7.6 cm in plexiglass cylinders, and then exposed to simulated rainfall at an intensity of 64 mm h−1for 1.5 h. The erodibility data indicated that as ferrihydrite increased from 0 to 16.80 Mg ha−1on acid soils, infiltration increased an average of 21.5% while runoff and soil loss decreased 20 and 40%, respectively. Conversely, infiltration decreased 37% while runoff and soil loss increased 21 and 34%, respectively for alkaline soils. Further, sediment size distributions measured at these same ferrihydrite rates indicated that the >250‐, and 250‐ to 53‐μm fractions increased 24 and 22% for acid soils and decreased 15 and 14%, respectively in alkaline soils. The <53‐μm fraction decreased 21% in the acid soils and increased 46% in the alkaline soils. These results suggest ferrihydrite develops a net positive charge in acid soil environments that leads to formation of bonds with negatively charged soil particles and an increase in water stable aggregation. Conversely, in alkaline soils, ferrihydrite becomes negatively charged which results in dispersion and aggregate instability. Thus, ferrihydrite appears to be an effective amendment for reducing runoff and soil loss from acid pH soils at amendment rates between 3.36 and 16.80 Mg ha−1

The probability of exceeding critical thresholds of Cd concentrations in the soil was mapped at a national scale. The critical thresholds in soil were based on food quality criteria for Cd in crops or in organs of cattle (Bos taurus), and were calculated by inverting a regression model for the Cd concentration in the crop, with the Cd concentration in soil, soil organic matter (SOM) content, clay content, and pH as predictors. The probability of exceeding the critical threshold for Cd in soil per node of a 500‐ × 500‐m grid was approximated by Monte Carlo simulation, using the estimated cumulative distribution functions (cdf) of SOM, clay, pH, and Cd as input. The cdfs were estimated by simple indicator kriging with local prior means. For SOM, clay, and pH, detailed maps of soil type and land use were used to define subregions with assumed constant local means of the indicators (a priori distributions). The cdfs were sampled by Latin hypercube sampling. We accounted for correlation between the actual and critical Cd concentrations in soil by drawing Cd values from cdfs conditional on SOM and clay. The estimated probability for grassland is negligible, even in areas with high Cd concentrations in soil, and for maize (Zea maysL.) land the probability is almost everywhere smaller than 5%. For arable soils, however, these probabilities commonly are larger than 5% when sugar beet (Beta vulgarisL.) or wheat (Triticum aestivumL.) is taken as a reference crop, and locally exceed 50%.

AbstractFor the identification of phosphorus-rich and phosphorus-leaky soils, various extraction methods have been proposed as indicators to estimate the risk of phosphorus (P) losses. In this study we compare and discuss the extractability of P from sandy soils, using various modifications of mild extractants (water and CaCl2), FeO-impregnated filter-paper strips (Pi-test), and ammonium oxalate (P-ox).In the soils studied, the amounts of water- and CaCl2-extractable P were (much) smaller than the amounts of P extracted with FeO-strips or with ammonium oxalate. With the water-based extraction method Pw (1:60 v:v soil:solution ratio), end-over-end shaking (Pw-2) compared with reciprocative shaking (Pw-1) resulted in increased amounts of extractable P in all soils. Because in the original Pw procedure reciprocative shaking and end-over-end shaking were implicitly treated as being exchangeable, the shaking method needs further standardization. Exponential relationships were found between P-1:2(water-extractable P at a 1:2 w:v soil:solution ratio; roughly comparable with P in the soil solution) on the one hand, and Pw-1(R2= 0.99; P< 0.001) and Pw-2(R2= 0.96; P< 0.001) on the other. The non-linearity of such relationships must be taken into account if Pwis used as an indicator to estimate the risk of P leaching, i.e., at high values of Pw, leaching may be underestimated if a linear instead of a non-linear relationship is used. A similar exponential relationship was observed between P-1:2and the P saturation degree (PSD) for soils sampled from the same site (R2= 1.00; P< 0.001). The relationship was not valid for soils from other sites, suggesting that the PSD as such cannot be used as an indicator for the risk of leaching dissolved P. Based on both PSD and P-l:2, a simple alternative scheme is proposed to provide guidance for selecting P-leaky soils and for evaluating the effectiveness of measures to restore such soils.

Biological channels and wheel track compaction zones increase heterogeneity of soil properties affecting infiltration, runoff, erosion, and solute movement. We hypothesized that crop, tillage system, and position relative to the plant row would alter the rate and pattern of water infiltration into a Grenada silt loam (fine‐silty, mixed, active, thermic, Oxyaquic Fraglossudalfs). We compared plant row (ROW), nontrafficked (UTK) and trafficked interrow (TRK) positions for cotton (Gossypium hirsutumL.) and grain sorghum [Sorghum bicolor(L.) Moench] grown with chisel plow, disk, or no‐tillage in the fourth year of a cropping system and tillage study. We used ring and tension infiltration measurements 3 to 10 wk after planting to determine infiltration rate and pore‐size distribution. Infiltration patterns and mobile water contents were studied by ponding Brilliant Blue FCF dye [(N‐ethyl‐N{4‐[(4‐{ethyl[(3‐sulfophenyl)methyl]‐amino}phenyl)(2‐sulfophenyl)methylene]‐2,5‐cyclohexadien‐1‐ylidene}‐3‐sulfoben‐zenemethanaminium hydroxide inner salt, disodium salt)](PYLAM products Co., Garden City, NY) and excavation. Neither tillage nor crop affected ponded infiltration rates that averaged 86.5 mm h−1for the ROW, 18.6 mm h−1for the UTK, and 2.4 mm h−1for the TRK position. Sorghum had more pores (0.04 m3m−3) between 1.0 and 0.2 mm diam. than cotton (0.02 m3m−3). Deeper and less uniform dye penetration reflected lower mobile water contents under no‐tillage (0.04 m3m−3) compared to tillage (0.20–0.27 m3m−3). This research confirmed the importance of continuous macropores in solute movement, but ponded infiltration rates were only weakly correlated with maximum dye depth and did not reflect tillage system differences in dye patterns.

For the identification of phosphorus-rich and phosphorus-leaky soils, various extraction methods have been proposed as indicators to estimate the risk of phosphorus (P) losses. In this study we compare and discuss the extractability of P from sandy soils, using various modifications of mild extractants (water and CaCl2), FeO-impregnated filter-paper strips (Pi-test), and ammonium oxalate (P-ox).

The phenomenon of longitudinal waves in shallow grain flows has been studied through laboratory experiments. The transport process of spherical particles on a metallic chute has been characterized for this purpose. The wave mode of material transport could be measured within selected combinations of flow parameters such as the angular inclination of the chute, the mean size of the grains and the mass flow rate. It has been observed that the moving particles tend to redistribute systematically in the direction of mean flow. As a result, nonlinear longitudinal waves evolve on the surface of the chute. Observations of the predominantly rolling mode of particle motion revealed significant particle dispersion away from the wavefronts. The frequency of inter-particle collisions was low in the dispersed flow regions but increased rapidly near the wavefronts to dissipate the excess kinetic energy, thus resulting in a large increase in the average volumetric solid fraction. In order to explain the appearance of discontinuities in the volumetric solid fraction, a theoretical model that preserves the overall balance of energy and allows a discontinuous periodic solution is examined here. The depth-averaged dispersed flow of the grains has been approximated by equations of motion similar to those of shallow fluid flow. The resistance to the rolling motion of the particles is expressed in terms of the hydrodynamic drag force. The theoretical model predicts the flow criterion for which the longitudinal waves would be self-sustaining.

The solubility and vertical displacement of Cu in near neutral arable soils largely depends on the presence of dissolved organic carbon (DOC) in solution. In this paper the solubility of Cu in sandy soils is predicted by a previously calibrated model that describes Cu binding to both low and high molecular weight components of DOC. Soil solution samples were obtained by centrifugation of field moist soil. Dissolved Cu concentrations increased with DOC and total soil Cu content, but decreased with organic matter and pH; after lime application, both DOC and Cu solubility were strongly reduced in the CuSO4‐treated soils. No single multiple linear regression equation could be obtained, however, that was able to describe the dissolved Cu concentrations in the various treatments. In contrast to this, a two‐species Langmuir model enabled us to describe the dissolved Cu concentrations in soil solution samples quite well in the pH range from 4.2 to 6 in both contaminated and noncontaminated soils (R2= 0.5–0.9 for various treatments). Measured Cu concentrations were generally underpredicted by the model below pH 4.2. In the manured soil, the predictive capacity of the model decreased with depth (R2= 0.6 in the topsoil to 0.3 in the deeper soil horizons), which is most likely related to changes in the nature of DOC. The use of a relatively simple model that requires only a few input parameters may prove useful for the prediction of the solubility of Cu under field conditions.

The effect of land use, total metal content and soil parameters on the distribution of Cd, Zn, and Cu between the solid phase and soil solution is examined in a large field survey. In situsoil solution samples were obtained by centrifugation of field moist soil samples from six depth layers (0 to 80 cm) in 30 Dutch forest and arable soils. The soils vary in texture, pH, organic matter content, and land use and represent major soil types in the Netherlands. Total metal contents in arable soils exceeded those of forest soils because of manure and fertilizer application and decreased with depth in both land use types. Cd and Zn solution concentrations were higher in forest soils and increased strongly below pH 5.5 despite the low total metal content. Cu solution concentrations were higher in agricultural soils and increased with dissolved organic carbon. Multiple linear regression showed that CEC and pH explained 49% (for Cu), 79% (for Cd), and 83% (for Zn) of the measured variation in distribution coefficients (Kd). In acid forest soils (pH < 4.5; Zntotal< 10 mg kg−1; Cdtotal< 0.3 mg kg−1), 80% of all measured Zn and Cd solution concentrations exceeded current ground water quality standards as a result of the high metal solubility at low pH. Taking into account the low acid buffering capacities in these soils, continuous acidification may cause further increase in the soil solution concentration of the metals considered in this paper.

In the Memphis catena, the well‐drained Memphis (fine silty, mixed, active, thermic Typic Hapludalfs) is more erodible than the moderately well‐drained Loring (fine silty, mixed, active, thermic Oxyaquic Fragiudalfs) and Grenada (fine silty, mixed, active, thermic Glossic Fragiudalfs). We hypothesized that soil wetness and Fe oxide status affects the erodibility of these soils. Samples (<2 mm) of A‐ and B‐horizons, collected from representative pedons at five locations, were characterized for standard physical and chemical properties. Simulated rainfall was applied (64 mm h‐1) to additional samples (<8 mm) in a rainfall simulator pan that had a 0.6 m × 0.6 m test area. Water dispersible clay (WDC) and soil loss averaged 7.2% and 9.21 Mg ha‐1for Memphis, 6.8% and 8.85 Mg ha‐1for Loring, and 6.1% and 8.71 Mg ha‐1for Grenada. Sediment Feo, Fed, and Feo/Fedratios were about 0.80, 1.5, and 0.50 times that of the soil, respectively. Correlation coefficients (r) for WDC and soil loss vs. Fe oxide variables exceeded 0.90 in some horizons, whereas, organic C (OC) and % clay were generally <0.60. However, OC vs. % sediment <53 µm had rvalues of 0.87 compared to 0.59 for some Fe oxide variables. Regression models derived for WDC and soil loss had Fe oxide parameters as principal variables in the best fit models and coefficients of determination that ranged from 0.208 to 0.922 (significant at P≤ 0.01). Results suggest that Fe oxides are more important than OC and clay content for determining the erodibility of these soils, particularly Feo/Fedratios which are negatively correlated with WDC and soil loss.

Abstract:  Conversion of arable land (maize) to pasture will affect the soil organic matter (SOM) content. Changes in the SOM content were studied using a size- and density-fractionation method and 13C analysis. Twenty-six years of maize cropping had resulted in a depletion of carbon stored in the macro-organic fractions (>150 μm) and an increase in the <20 μm fraction. Maize-derived carbon in the upper 20 cm increased from 10% in the finest fraction (<20 μm) to 91% in the coarse (>250 μm), light (b.d. <1.13 g cm–3) fractions. Pasture installation resulted in a rapid recovery of the total SOM content. Up to 90% of the pasture-derived carbon that was mineralized during maize cropping was replaced within 9 years. Especially the medium and coarse size (>150 μm) and light (b.d. <1.13 g cm–3) fractions were almost completely regenerated by input of root-derived SOM. The amount of medium-weight and heavy macro-organic fractions (>150 μm; b.d. >1.13 g cm–3) in the 0- to 20-cm layer was still 40–50% lower than in the continuous pasture plots. Average half-life times calculated from 13C analyses ranged from 7 years in the light fractions to 56 years in heavy fractions. Fractionation results and 13C data indicated that mechanical disturbance (plowing) during maize cropping had resulted in vertical displacement of dispersed soil carbon from the 0- to 20-cm layer down to 60–80 cm. Conversion of arable land to pasture, therefore, not only causes a regeneration of the soil carbon content, it also reduces the risk of contaminant transport by dispersed soil carbon.

Predictions of soil erodibility factors for selected clay subsoils were studied in relation to physical and chemical properties. Erodibility factors were determined from soil erosion rates on scalped surfaces during a series of simulated rainstorms. Subsoils were analyzed for their textural, chemical, and mineralogical composition. A predictive model, derived from previously gathered data of 46 surface soils, was used to determined the significance of soil properties in predicting subsoil erodibility. Weighted linear regression analysis using data from surface soils of the test model and seven selected subsoils indicated that a textural parameter and the percent of iron plus aluminum extractable with citrate‐dithionite‐bicarbonate (CDB) were significant prediction properties of erodibility for these clay subsoils. Multiple linear regression yielded a prediction equation with a coefficient of multiple determination of R2= 0.90.

Knowledge of porosity, air permeability, pore structure, and surface layering of soils is desirable in agricultural research. The conventional techniques are invasive, typically requiring sample extraction. When monitoring seasonal changes, the conventional methods disrupt considerable proportions of the test plot surface. The sample area used in conventional measurements may be too small to represent the variations in the test plot. Here, the feasibility of acoustical techniques for monitoring surface air porosity (total porosity minus volumetric water content), air permeability, and pore structure and the variation of these properties to depths of several centimeters below the surface is demonstrated. Test soil plots prepared using three soil materials, masonry sand, a Grenada silt loam (fine‐silty, mixed, thermic Glossic Fragiudalf) and a Catalpa silty clay (fine, montmorillonitic, thermic Fluvaquentic Hapludoll), were considered. Variation in water content and compaction of each soil material were considered. Both acoustic reflection and transmission measurements were made in the audio‐frequency range. The soils are modeled as air‐filled, rigid‐framed porous media. The acoustic‐reflection measurements involve analysis of propagation data from a small loudspeaker and two vertically separated microphones. The acoustic‐transmission measurement requires a specially designed probe microphone. Analysis of the acoustic‐reflection data yields qualitative indications of the relative air permeability of the soils. The transmission measurement yields information about the changes in air permeability with depth. Quantitative information on surface porosity, air permeability, tortuosity, and layering is presented by fitting theoretical predictions based on the soil model to the measured sound reflection and transmission data. The acoustically determined air porosity for the soils considered is within 10% of the values determined by gravimetric techniques.

The microrelief of the soil surface, termed soil surface roughness, affects water movement into a soil profile as well as seedling germination in the seedbed. When analyzing surface roughness, the selection of a measurable, physically significant parameter describing roughness is critical. An evaluation was conducted on eight roughness parameters, including maximum peak height, a microrelief index (the area per unit transect length between the measured surface profile and the least‐squares regression line through all measured positions of the transect), peak frequency, and MIF (the product of the microrelief index and peak frequency). The objective of the study was to select the parameter being the best descriptor of soil surface roughness. An automated, noncontact profiler was used to obtain surface profiles along transects, 5‐cm apart, of 1‐m by 1‐m plots after a cultivation and a simulated rainfall application at each of three different stages of soybean [Glycine max(L.)] development. For each cultivation, surface profiles were obtained on bare plots before rainfall and on adjacent vegetated plots after rainfall. The common logarithm of the MIF parameter was selected as the best descriptor of surface roughness because of its sensitivity to simulated rainfall as a source of variation, and its consistent response to such rainfall. MIF can also account for spatial dependency and can be measured relatively precisely.

Soil surface roughness, the configuration of the soil surface, affects infiltration, runoff velocities, erosion, and plant establishment and growth. One difficult aspect of studying surface roughness is that parameters describing roughness vary spatially. Eight roughness parameters were identified as possible indices of soil surface roughness. They were maximum peak height, maximum depression depth, peak frequency, the ratio of peak frequency to peak height, microrelief index (the area per unit transect length between the measured surface profile and the least‐squares regression line through the measured elevations of the transect), the ratio of microrelief index to peak height, the ratio of microrelief index to peak frequency, and lastly the product of the microrelief index and peak frequency (the MIF parameter). The objective of the study was to determine the spatial variation of the eight indices using a semivariogram analysis. An automated, noncontact profiler was used to obtain surface profiles along transects 5 cm apart of 1‐m by 1‐m plots after a cultivation and a simulated rainfall application at each of three different stages of soybean [Glycine max(L.)] development. For each cultivation, surface profiles were obtained on bare plots before rainfall and on adjacent vegetated plots after rainfall. None of the eight indices commonly showed spatial dependence. When a roughness parameter was spatially dependent, however, its semivariogram usually was spherical, linear with a nugget constant, or exhibited a hole effect. Across all plots on which they were found to be spatially dependent, the indices exhibited zones of influence averaging from 15 to 20 cm.

The effect of P fertilizer mixed into soil on the P composition of runoff was studied. Runoff samples from artificial rainstorms on fallow plots of Russell sil soil, and P enriched soil‐water mixtures (1:50) of Russell sil and selected other soils were analyzed for water soluble orthophosphate and extractable, total, and organic P in sediment. The relation of P addition rate to the soluble orthophosphate or sediment extractable phosphorus level in runoff was approximately linear. The relation of soluble orthophosphate to extractable P in soil‐water systems was linear for most soils studied. Soluble orthophosphate and extractable P in sediment were not related to total P or to organic P in sediment. A procedure was suggested for estimating the soluble orthophosphate concentration in runoff from fertilized wet soil using laboratory analyses.

Soil surface roughness greatly affects surface sealing and runoff generation, yet little information is available about the effect of roughness on the spatial distribution of runoff and on flow concentration. This study tested the hypothesis that runoff distribution and flow concentration differ with roughness and affect the amount of soil loss. Sequences of four rainstorms of constant rainfall amount but decreasing intensity (60, 45, 30, and 15 mm h−1) were applied to the Ap horizon material of a loess soil (Glossic Fragiudalf) packed into a 0.6 by 3.7 m flume. Rough, medium, and smooth soil surfaces were studied at 17, 8, and 2% slope steepness. Surface roughness and flow pathways were visualized with digital elevation maps obtained from laser microrelief measurements. On the smooth surfaces, runoff was uniformly distributed during the first two rainstorms and soil losses were 0.23, 0.07, and 0.12 kg m−2for the first and 2.26, 0.35, and 0.2 kg m−2for the second storm at 17, 8, and 2% slope steepness, respectively. On the rough and medium surfaces, flow concentrated in pathways between clods and soil losses were up to eight and three times that on the smooth surfaces during the first and second storms, respectively. During the last two storms, flow concentrated also on the smooth surfaces and soil losses were similar for the three initially different surface configurations. Surface roughness effects on runoff amount were minor, but roughness affected the spatial distribution of runoff, thereby affecting the amount of soil loss.

To investigate the role of dissolved Ca on the sorption and complexation behaviour of dissolved organic carbon (DOC), and the effect on dissolved Cu concentration, batch sorption studies and titration experiments have been performed. Both adsorption and desorption studies showed that the DOC concentration depends on the presence of Ca. With increasing Ca content, the DOC concentration decreased as a result of sorption and precipitation processes. The formation of aqueous Ca-DOC complexes could be described well with a 1:1 Ca:DOC ratio. Log KCaDOC values for the formation of Ca-DOC complexes ranged from 3.7 to 4 in the low pH range (3.5 to 6, interaction with carboxyl groups) and from 5.8 to 6 in the pH range from 7 to 9 (interaction with phenolic groups). The results indicate that a large part of the available DOC is in a Ca form at near neutral pH values. In batch sorption experiments, the addition of Ca2+ significantly reduced the DOC as well as the Cu concentration in solution. This indicates that sorption of Ca-DOC complexes at near neutral pH is more important in regulating the Cu solution concentration compared to cation exchange processes.

The resistance to penetration developed during the formation of fragipan horizons effectively excludes plant roots from the water stored in this zone. Thus, plant roots are believed to be restricted to the use of water stored in the profile between the fragipan and soil surface. This study was conducted to determine if fragipan horizons contribute water to plant rooting zones during the growing season. Twelve experimental field plots were installed at each of three sites situated on Grenada silt loam (fine‐silty, mixed, active, thermic Glossic Fragiudalfs). Based on relative depths to the fragipan horizon, these three sites represented slight, moderate, and severely eroded phases of the soil. Access tubes were inserted to a depth of 30.5 cm below the fragipan surface on six of the plots at each site. Water contents were measured weekly by a combination of gravimetric and neutron probe methods from the 1984 through the 1987 growing seasons. Results indicate that the fragipan horizons contributed water to the overlying profile each growing season at all three sites. The extent of water loss from the fragipan was determined by its proximity to the soil surface. For the four growing seasons, the fragipan horizon contributed on average 15.6% of the water lost at the severely eroded site, compared with 5.5 and 6.1% at the slightly and moderately eroded sites, respectively. These results suggest that plants grown on soils with fragipan horizons have indirect access to water stored in that zone. Consequently, yield data from such studies must be carefully interpreted when comparing sites with a range of depths to fragipan.

Loess soils are among the most erodible soils. Therefore, evaluating and enhancing infiltration is paramount in controlling soil loss. A laboratory study was conducted to evaluate the relative difference in infiltration among selected loess surface and subsurface soils from Belgium, Canada, China, and the United States, representing the major loess belts of the Northern Hemisphere. Soils were subjected to simulated rainstorms of constant intensity (I= 41.1mm· h−1), duration (2 hours), and energy rate (27.0 J · m−2 per mm of rain). Infiltration, runoff, and soil water pressure were continuously monitored. Infiltration was described by a linear relationship for the pre-ponding period and by a power series for the post-ponding period. Differences in infiltration response were attributed to differences in soil properties such as differences in organic matter, particle size, swelling clay content, Fe-oxyhydroxides, and carbonates. Despite the high organic carbon content and coarser texture of the Canadian loess surface soil, the presence of highly expansive smectitic clay caused a rapid reduction in infiltration rates indicating the importance of soil mineralogical constituents in surface seal development.

The effect of tillage methods on the N and P composition in runoff water and runoff sediment from corn (Zea maysL.) plots was studied on Bedford silt loam soil by applying simulated rainstorms. Five tillage‐planting systems were compared: coulter‐plant, till‐plant, chisel‐plant, disk and coulter‐plant, and conventional‐plant. The coulter and chisel systems controlled soil loss, but runoff water contained high levels of soluble N and P from surface‐applied fertilizer. The disk and till systems were less effective in controlling soil erosion, but had lower concentrations of soluble N and P in runoff water. Conventional tillage, in which fertilizers were plowed under, had the highest losses of soil and water but small losses of soluble N and P. However, high percentages of the total nutrients removed by runoff were components of the sediment from all treatments.

Summary: An implicit relationship between root size and soil reaction to root growth pressure is developed for a cohesionless soil from data of one-dimensional consolidation tests. The mathematical model employed describes a phenomenological procedure of relating root size and root frequency to soil mechanical parameters. The model is based on: (i) a simplification of the observed dependency of void ratio on compression pressure, and (ii) the assumption of an inverse relationship over the domain of root influence between the radial stress and the distance from the axis of the root. As radial expansion of a root proceeds, three successive and mathematically distinct stages of root growth are recognized in a preconsolidated soil. Relationships between root growth pressure and root size were computed for various combinations of bulk density, preconsolidation pressure, and values of the compression index in and beyond the range of preconsolidation. Root frequencies were calculated for a number of hypothetical situations assuming a hexagonal network of evenly distributed roots.

Square initiation was reduced by increased tension limit and was directly related to plant height increase prior to 4 weeks past first bloom. Associated with the greater square production of treatments at low tension all season was a greater number of squares shed. Bloom production was also progressively reduced by increasing the tension limit. Prior to maximum fruit load square and post‐bloom abscission relative to total fruit production was not significantly affected by tensions of 2.5 atmospheres.

Pancreatitis is the most common complication of endoscopic retrograde cholangiopancreatography (ERCP). Prophylactic rectal administration of non-steroidal anti-inflammatory drugs (NSAIDs) is considered as standard of care to reduce the risk of post-ERCP pancreatitis. It has been suggested that aggressive hydration might further reduce this risk. Guidelines already recommend aggressive hydration in patients who are unable to receive rectal NSAIDs, although it is laborious and time consuming. We aimed to evaluate the added value of aggressive hydration in patients receiving prophylactic rectal NSAIDs.

A laboratory rainfall simulator with high intensity precision and nearly uniform rain distribution was developed for studying rain infiltration into soils and soil detachability by rainfall. The rainfall simulator consists of an assembly of closely packed hypodermic syringes with plungers driven by a common plate. Rainfall intensity is determined by controlling the plunger speed at variable motor speeds. Rain is distributed uniformly by superpositioning three independent motions—rotation, and perpendicular and linear motions in the horizontal plane. Rainfall intensities were generally within 2.5% of predicted values. The average coefficient of variation of rain distribution for various rainfall intensities over a 100‐cm2area was reduced from 31.9% with no motion to 8.5% with rotation and linear motions.