bluuebunny/crossref_metadata_2025 huggingface dataset:
Accuracy of Aerial Telemetry in Fisheries Studies
Authors: Roberts James J. , Rahel Frank J.
Published: May 2005

Radiotelemetry has become an important method for examining movement patterns of fishes. The use of aircraft allows transmitter-implanted fish to be tracked over long distances and in areas difficult to access on the ground. However, the accuracy of aerially determined locations can limit the types of conclusions one can draw about fish habitat use. We utilized aerial telemetry while studying the effects of irrigation canals on a population of cutthroat trout Oncorhynchus clarkii. To determine the accuracy of aerially determined locations, we used a method common in terrestrial studies whereby transmitters are placed at known locations and then located by a naïve pilot. These aerially determined locations were then compared with the known locations of transmitters to determine the mean error associated with aerial telemetry. In our study, we found that aerially acquired location errors ranged from 22 to 426 m and had a mean of 178 m. In a review of recent studies that used aerial telemetry, we found that 15 of 34 (44%) terrestrial studies but only 4 of 17 (24%) aquatic studies reported an estimate of the error associated with aerial telemetry locations. The overall mean location error of these studies was 158 m. We urge aquatic biologists to consider location errors when using aerial telemetry, especially when making inferences about fish habitat use or movement patterns.
PIT-Tag Detection System for Large-Diameter Juvenile Fish Bypass Pipes at Columbia River Basin Hydroelectric Dams
Authors: Axel G. A. , Prentice E. F. , Sandford B. P.
Published: May 2005

We developed a prototype detection system with increased reading range for passive integrated transponder (PIT) tags. The system eliminates the need to route juvenile salmonids to sampling and collection facilities for detection and allows fisheries management greater flexibility in safely bypassing juvenile salmonids at dams. This technology can be applied to PIT-tag studies elsewhere, especially those directed at recovery of threatened and endangered salmonid populations. The system exceeded the intended goal of 95% tag-reading efficiency and yielded reading efficiencies near 100% for the four antennas combined. In tests using juvenile steelhead Oncorhynchus mykiss and subyearling Chinook salmon O. tshawytscha, the system worked as designed under a variety of release times and densities. Both direct and indirect methods were used to evaluate the system. The direct method used a known number of tagged fish released at a specific location and compared that number to the number of unique tag codes read. Using this method, over 98% reading efficiency was obtained under all test conditions. The indirect method relied upon a statistical comparison of reading performance between antennas during the juvenile migration season. This method showed that the system efficiency ranged between 99.5% and 100%.
Initial Predation of Stocked Fingerling Largemouth Bass in a Texas Reservoir and Implications for Improving Stocking Efficiency
Authors: Buckmeier David L. , Betsill Robert K. , Schlechte J. Warren
Published: May 2005

We assessed the importance of initial predation as a source of mortality of stocked fingerling Florida largemouth bass Micropterus salmoides floridanus (30–46 mm total length). Florida largemouth bass were tagged with coded wire tags and stocked (3,000 fish/site) at six sites in Elm Creek Embayment of O. H. Ivie Reservoir, Texas—the location of an earlier study in which the immediate mortality of stocked fish was found to be highly variable. Stocked fish were eaten by at least five species of predators that varied widely in size. Ninety-three percent of the stocked fish recovered from predator stomachs were consumed by juvenile and adult largemouth bass M. salmoides and smallmouth bass M. dolomieu. Assuming a capture efficiency of 8% for our predator sampling, losses of stocked fish to predation were as high as 27.5% within 12 h of stocking, and losses generally increased with predator density. In comparison, the mortality of stocked fish held in predator-free enclosures was only 3.5% at 84 h poststocking, indicating that mortality resulting from transport and other variables was low and similar among stocking sites (P = 0.17). This study suggests that predation was the primary factor affecting the poststocking survival of fingerling Florida largemouth bass, and we recommend that managers consider predator densities when selecting stocking sites. Future efforts should examine the relationships between predation and habitat variables such as habitat composition and habitat complexity. Additional research should evaluate alternative stocking strategies such as using larger fish and habituating stocked fish before release.
Effect of Baiting on Hoop Net Catch Rates of Endangered Humpback Chub
Authors: Stone Dennis M.
Published: May 2005

The effects of unbaited, scented (odor emitted by inaccessible hatchery feed), and baited (accessible feed) single-throated hoop nets on the catch rates of the federally endangered humpback chub Gila cypha (≥100 mm total length) were assessed in the Little Colorado River, Arizona, to determine how baiting affected the catch of these fish. Of a total of 1,297 unique humpback chub captured, 262 (20%) were caught in 179 unbaited nets, 330 (25%) in 179 scented nets, and 705 (54%) in 178 baited nets. Humpback chub retention in unbaited nets did not differ from a 50:50 chance event (P = 0.075) but probably peaked in baited nets where these fish were preoccupied with feeding (i.e., gorging themselves), which would explain the higher catch rates in baited than in scented or unbaited nets (P ≤ 0.001). Moreover, humpback chub catch rates were not significantly higher in scented than in unbaited nets (P = 0.779), which suggests that elevating both “fish attraction” and “fish retention” are essential to substantially increase their captures in these nets. However, scenting may still be a viable option when used in conjunction with passive gears possessing higher fish retention capabilities or to target species less prone to escape. The findings of this study should provide valuable insight to anyone wishing to optimize catch rates by baiting or scenting passive entrapment gear.
Temporal and Spatial Relationships between Within‐Field Yield Variability in Cotton and High‐Spatial Hyperspectral Remote Sensing Imagery
Authors: Zarco‐Tejada P. J. , Ustin S. L. , Whiting M. L.
Published: May 2005

Traditional remote sensing methods for yield estimation rely on broadband vegetation indices, such as the Normalized Difference Vegetation Index, NDVI. Despite demonstrated relationships between such traditional indices and yield, NDVI saturates at larger leaf area index (LAI) values, and it is affected by soil background. We present results obtained with several new narrow‐band hyperspectral indices calculated from the Airborne Visible and Near Infrared (AVNIR) hyperspectral sensor flown over a cotton (Gossypium hirsutum L.) field in California (USA) collected over an entire growing season at 1–m spatial resolution. Within‐field variability of yield monitor spatial data collected during harvest was correlated with hyperspectral indices related to crop growth and canopy structure, chlorophyll concentration, and water content. The time‐series of indices calculated from the imagery were assessed to understand within‐field yield variability in cotton at different growth stages. A K means clustering method was used to perform field segmentation on hyperspectral indices in classes of low, medium, and high yield, and confusion matrices were used to calculate the kappa (κ) coefficient and overall accuracy. Structural indices related to LAI [Renormalized Difference Vegetation Index (RDVI), Modified Triangular Vegetation Index (MTVI), and Optimized Soil‐Adjusted Vegetation Index (OSAVI)] obtained the best relationships with yield and field segmentation at early growth stages. Hyperspectral indices related to crop physiological status [Modified Chlorophyll Absorption Index (MCARI) and Transformed Chlorophyll Absorption Index (TCARI)] were superior at later growth stages, close to harvest. From confusion matrices and class analyses, the overall accuracy (and kappa) of RDVI at early stages was 61% (κ = 0.39), dropping to 39% (κ = 0.08) before harvest. The MCARI chlorophyll index remained sensitive to within‐field yield variability at late preharvest stage, obtaining overall accuracy of 51% (κ = 0.22).
Sulfur Fertilization of Bahiagrass with Varying Levels of Nitrogen Fertilization on a Florida Spodosol
Authors: Kalmbacher R. S. , Ezenwa I. V. , Arthington J. D. , Martin F. G.
Published: May 2005

Low levels of available S in soils may limit bahiagrass (Paspalum notatum Flugge) growth in Florida. To characterize the response of bahiagrass to S fertilizer, we annually applied a factorial combination of four N (N0–N255 = 0, 85, 170, and 255 kg ha−1, respectively) and S (S0–S285 = 0, 95, 190, and 285 kg ha−1, respectively) levels to a >40‐yr‐old pasture and measured forage yield, N and S concentrations, and N and S uptake at 35, 70, and 105 d after fertilization (DAF) over 3 yr. There were highly significant N × S fertilizer interactions for yield, concentration of N, and N uptake. In the absence of N, each of these responses increased with increasing rates of S, but as level of N increased, these three responses to S diminished. For example, with N0, yield ranged from 1140 to 2640 kg dry matter (DM) ha−1 over S0 to S285, but with N255, yield did not vary (mean 3210 kg DM ha−1). Up to 80 kg N ha−1 yr−1 came from apparent mineralization of soil organic matter (OM) as a result of addition of S to plots that received no N. At 35 DAF, concentrations of S in forage ranged from 2.6 to 3.8 g kg−1 with S0 to S285. Maximum annual uptake was 28 kg S ha−1 with recovery at 136 g S kg−1 of applied S. With 56 to 67 kg N ha−1 yr−1, as is common on Florida ranches, fertilization with S may not be necessary on older pasture.
Legume Green Fallow Effect on Soil Water Content at Wheat Planting and Wheat Yield
Authors: Nielsen David C. , Vigil Merle F.
Published: May 2005

Growing a legume cover crop in place of fallow in a winter wheat (Triticum aestivumL.)–fallow system can provide protection against erosion while adding N to the soil. However, water use by legumes may reduce subsequent wheat yield. This study was conducted to quantify the effect of varying legume termination dates on available soil water content at wheat planting and subsequent wheat yield in the central Great Plains. Four legumes [Austrian winter pea,Pisum sativumL. subsp.sativumvar.arvense(L.) Poir.; spring field pea,P. sativumL.; black lentil,Lens culinarisMedikus; hairy vetch,Vicia villosaRoth.) were grown at Akron, CO, as spring crops from 1994 to 1999. Legumes were planted in early April and terminated at 2‐wk intervals (four termination dates), generally starting in early June. Wheat was planted in September in the terminated legume plots, and yields were compared with wheat yields from conventional till wheat–fallow. Generally there were no significant differences in available soil water at wheat planting due to legume type. Soil water at wheat planting was reduced by 55 mm when legumes were terminated early and by 104 mm when legumes were terminated late, compared with soil water in fallowed plots that were conventionally tilled. Average wheat yield was linearly correlated with average available soil water at wheat planting, with the relationship varying from year to year depending on evaporative demand and precipitation in April, May, and June. The cost in water use by legumes and subsequent decrease in wheat yield may be too great to justify use of legumes as fallow cover crops in wheat–fallow systems in semiarid environments.
Illinois Bundleflower Forage Potential in the Upper Midwestern USA: II. Forage Quality
Authors: Fischbach Jason A. , Peterson Paul R. , Ehlke Nancy J. , Wyse Donald L. , Sheaffer Craig C.
Published: May 2005

Illinois bundleflower [Desmanthus illinoensis (Mich.) MacMill] is a warm‐season perennial legume native to the central USA. Little is known about its forage quality in the upper midwestern USA. Two experiments were established at four Minnesota locations in 2000 to evaluate the effects of N fertilization, maturity at harvest, and residual height of cutting on the acid detergent fiber (ADF), neutral detergent fiber (NDF), crude protein (CP), in vitro true digestibility (IVTD), in vitro dry matter digestibility (IVDMD), and leaf proportion of three Illinois bundleflower (IBF) ecotypes. Whole‐herbage forage quality was greatest (P < 0.05) at early flower in mid‐July with average ADF, NDF, and CP concentrations of 315, 352, and 180 g kg−1, respectively. Fiber values increased to 412 and 479 g kg−1, respectively, while CP decreased to 129 g kg−1 at late pod in mid‐August. Leaf proportion decreased (P < 0.05) from 618 g kg−1 at early flower to 335 g kg−1 at late pod while leaf CP decreased (P < 0.05) from 216 to 147 g kg−1. Whole‐herbage IVDMD and IVTD concentrations decreased (P < 0.05) from 470 and 648 g kg−1 at early flower to 390 and 560 g kg−1 at late pod, respectively. Increasing residual cutting height from 15 to 35 cm decreased (P < 0.05) ADF and NDF concentrations by an average of 50 g kg−1 and increased (P < 0.05) IVTD, IVDMD, and CP concentrations by 43, 39, and 20 g kg−1, respectively. Illinois bundleflower can provide good quality summer forage in the upper midwestern USA, but more research is needed to ascertain the implications of its low IVDMD on animal performance.
Tillage and Urea Ammonium Nitrate Fertilizer Rate and Placement Affects Winter Wheat following Grain Sorghum and Soybean
Authors: Kelley K. W. , Sweeney D. W.
Published: May 2005

In the eastern Great Plains, winter wheat (Triticum aestivum L.) is often rotated with other crops to diversify cropping systems. In these multicropping systems, wheat typically is planted with conservation tillage methods, but previous crop residues influence fertilizer N management. This field study was conducted from 1992 through 2001 in southeastern Kansas on a Parsons silt loam soil (fine, mixed, thermic, Mollic Albaqualf). The objectives were to determine effects and interactions of previous crop {grain sorghum [Sorghum bicolor (L.) Moench] and soybean [Glycine max (L.) Merr.]}, tillage system [reduced tillage (RT) and no‐tillage (NT)], N rate (67 and 134 kg ha−1), and preplant placement (surface‐broadcast and subsurface‐knife) of urea ammonium nitrate solution (UAN, 280 g kg−1) on wheat grain yield, yield components, and plant N uptake in a 2‐yr cropping rotation. Wheat yields averaged 3.39 Mg ha−1 following soybean compared with 2.90 Mg ha−1 following grain sorghum. Tillage effects on grain yield were smaller than other treatment factors, averaging 3.23 Mg ha−1 for RT and 3.06 Mg ha−1 for NT. Grain yields were greatest in all cropping systems for the high‐N‐rate subsurface‐knife treatment. Plant N uptake responses indicated that grain yield differences were primarily related to greater immobilization of both fertilizer and soil N following grain sorghum, compared with soybean, and to better utilization of subsurface‐knifed N than surface‐broadcast N. Results indicate that wheat yield potential is more strongly influenced by previous crop, fertilizer N rate, and N placement method than tillage system.
Management and Production Potential of Value‐Added Soybean Cultivars in South Central USA
Authors: Kumudini Saratha , Grabau Larry J. , Pfeiffer Todd W. , Steele Colleen C.
Published: May 2005

Growth of value‐added commodities, especially high‐protein and tofu soybean [Glycine max (L.) Merr.], may offer a profitable option for growers faced with the decline in traditional crops in the south central region of the USA. There is limited information on the production potential and management options necessary for optimal production of value‐added soybean crops in this region. The objectives of this study were (i) to determine the production potential of value‐added soybean cultivars in the south central region, and (ii) to evaluate various management options for optimal production in this area. Three tofu‐type and three high‐protein soybean cultivars were compared with commodity‐type (check) soybean cultivars under various N and plant density treatments over 4 location/years. Yield and yield component data were collected including seed protein and oil concentrations. Both high protein and tofu‐type soybean cultivars had comparable yields and generally greater protein concentrations and larger seed size (tofu‐type soybean) than an equivalent check cultivar. The exceptions were cultivars that had, on average, a greater than 10% higher protein concentration than the check cultivar. These higher protein cultivars generally yielded less than other value‐added soybean cultivars or the standard check cultivar. The value‐added soybean cultivars responded well to management practices currently being used to grow standard commodity cultivars. Neither change in plant population density nor late‐season fertilizer applications was necessary to maintain total yield and yield components at a level equivalent to the check cultivar. There is good production potential of value‐added soybean cultivars in the south central region, even when grown with current equipment and management practices utilized for commodity soybean crop production.
Evaluating a Leaf‐Level Canopy Assimilation Model Linked to CERES‐Maize
Authors: Lizaso J. I. , Batchelor W. D. , Boote K. J. , Westgate M. E. , Rochette P. , Moreno‐Sotomayor A.
Published: May 2005

The simple approach of calculating crop growth rate as the product of intercepted light and radiation use efficiency may not adequately represent plant growth under stress conditions. We developed a photosynthesis and respiration model for maize (Zea mays L.) and linked it to CERES‐Maize v.3.7, calling the new model CERES‐PR. The purpose of this work was to evaluate CERES‐PR simulation of photosynthesis at three levels of integration: instantaneous leaf assimilation, hourly canopy assimilation, and seasonal crop growth under conditions where water and N supply were not limiting growth. Instantaneous leaf assimilation measured in field plots were obtained in the central portion of the 13th leaf on three dates during the grain filling to test the model at the leaf level. Carbon dioxide fluxes measured above the canopy with the eddy correlation technique were used to test the model at the canopy level. The progression of leaf area index (LAI) and aboveground biomass from experiments planted at latitudes ranging from 21 to 45° N was used to evaluate the seasonal simulation of crop growth. CERES‐PR was in close agreement with measured values. A sensitivity analysis indicated that the temperature function affecting leaf assimilation have a large impact in the simulated growth and grain yield. The new model provides opportunities to simulate plant processes more realistically under stress. Our future efforts will focus on developing new modules to simulate energy balance and stomatal conductance to incorporate into CERES‐PR leaf‐level C, water, and N balances.
Supplemental Irrigation at Reproductive Growth Stages to Improve Popcorn Grown at Different Populations
Authors: Sweeney Daniel W. , Marr C. W.
Published: May 2005

When irrigation sources are limited, supplemental irrigation at selected growth stages may help avoid crop stress. The objective of this study was to determine the effect of limited, supplemental irrigation at two reproductive growth stages of popcorn (Zea mays L.) grown at different populations. The experiment was conducted from 1995 through 1998 on a Parsons silt loam (fine, mixed, thermic Mollic Albaqualf). The experimental design was a randomized complete block with a split‐plot arrangement of treatments. Six irrigation schemes of no irrigation, application of 2.5 or 5 cm at R1 (silk stage) or R3 (milk stage), and 2.5 cm at both R1 and R3 were main plots, and populations of 37000, 49000, and 62000 plants ha−1 were subplots. Popcorn yield was affected by irrigation in only 2 of 4 yr. In the driest growing season (1996), yields were low, but either 2.5 or 5 cm of irrigation applied at R1 increased yields by 60% or more compared with irrigations at R3 or no irrigation. In 1997, 2.5 cm of irrigation at R1 or 2.5 cm at both R1 and R3 resulted in 23 to 27% greater yield than with no irrigation. These responses were partially explained by 12 to 13% greater number of kernels per ear. The optimum plant population was 49000 plants ha−1; this treatment maximized yield, kernel weight, and produced one ear per plant. Responses to irrigation were not affected by plant populations for any measured parameters. Popping expansion ratio was unaffected by treatments. Supplemental irrigation at critical reproductive growth stages influences yield but is inadequate to provide consistent yield and quality improvements for popcorn grown in the eastern Great Plains.
Sugarcane Yield, Sugarcane Quality, and Soil Variability in Louisiana
Authors: Johnson Richard M. , Richard Edward P.
Published: May 2005

This study was conducted to determine the extent of temporal and spatial variability present in commercially cultivated sugarcane (interspecific hybrids ofSaccharumspp. cv. LCP 85‐384) grown in South Louisiana. Sugarcane fields at two locations were harvested for three consecutive years (2001–2003) in a grid pattern with a single‐row, chopper harvester and a field transport wagon equipped with electronic load sensors to determine cane yields. Sugar yield and quality were determined from a random cane sample from each grid cell, and soil samples were collected after harvest from each grid cell (2002–2004). At each location, the majority of soil properties exhibited nonnormal distributions with coefficients of variation ranging from 1 to 56% over all years and locations, and all soil properties were spatially correlated with the range varying from 26 to 241 m. Cane and sugar yields and sugar quality parameters at both locations were found to exhibit nonnormal distributions in selected years, and the coefficients of variation ranged from 5 to 20% over all years and locations. Cane and sugar yields and quality parameters were spatially correlated with a range varying from 26 to 187 m with the exception of theoretically recoverable sugar and fiber at one location in 2003. Soil S and Ca/Mg ratio were correlated to all sugar parameters at one location, and soil organic matter and soil buffer pH were correlated to all sugar parameters at the second location. These data would indicate that sufficient variability exists in commercially produced Louisiana sugarcane to justify a precision agricultural management approach.
Weed Interference and Glyphosate Timing Affect Corn Forage Yield and Quality
Authors: Cox William J. , Hahn Russell R. , Stachowski Paul J. , Cherney Jerome H.
Published: May 2005

Corn (Zea mays L.) planting and the first harvest of perennial forages overlap in the northeastern USA in some years. The use of glyphosate [N‐(phosphonomethyl)glycine]–resistant corn may help dairy producers lessen their workload during this time by allowing for a timely glyphosate application after completion of the first harvest of perennial forages. We evaluated 92 and 103‐d hybrids to determine the impact of season‐long weed interference and the optimum timing for glyphosate application on corn forage yield and quality. Season‐long weed interference vs. weed‐free corn in two competitive growing seasons reduced dry matter (DM) accumulation at silking (R1 stage) by 50 to 65%, DM yield by 70 to 75%, and calculated milk yield by 75 to 80%. Season‐long weed interference reduced milk per megagram, a forage quality index, by 10% in a dry year by preventing grain formation. Glyphosate application at the three to four leaf stage (V3–V4) vs. weed‐free corn resulted in similar DM accumulation at the R1 stage, DM content at harvest, DM yield, forage quality, and calculated milk yield in both years. Glyphosate application at the V5–V6 stage vs. weed‐free corn increased milk per megagram by 7% in the dry year, but resulted in 20 to 25% less DM yield in both years. Dairy producers in the northeastern USA should apply glyphosate by the V3–V4 stage in competitive growing conditions, regardless of hybrid maturity, which may overlap with the first harvest of perennial forages in some years.
Leaf Color Chart for Managing Nitrogen Fertilizer in Lowland Rice in Bangladesh
Authors: Alam M. Murshedul , Ladha J. K. , Khan S. Rahman , Foyjunnessa  , Harun‐ur‐Rashid  , Khan A. H. , Buresh R. J.
Published: May 2005

Nitrogen (N) fertilizer, while essential for high yield and profit in rice (Oryza sativa L.) farming, is often managed inefficiently by Asian rice farmers. We evaluated the leaf color chart (LCC) as a simple tool for improving the time and rate of N fertilizer use in farmers’ fields with no limitation in water supply in southwestern Bangladesh. Use of the LCC for N management consistently increased grain yield and profit as compared with the farmers’ fertilizer practice across the three wet (Aman) and three dry (Boro) seasons, which each involved 1 to 5 villages and a total of 8 to 36 farmers. Use of the LCC for N management without any other change in the farmers’ fertilizer or crop management increased average grain yield by 0.1 to 0.7 Mg ha−1 across villages and seasons. This corresponded to an average added net return of US$ 41 to 65 ha−1 season−1, which arose largely because of increased yield. Grain yields were increased by an additional ≥0.3 Mg ha−1 at about half the combinations of villages and seasons when the LCC was combined with recommended P, K, S, and Zn fertilization. Grain yields were further increased by another ≥0.4 Mg ha−1 at about half the combinations of villages and seasons when the LCC and recommended P, K, S, and Zn fertilization were combined with improved crop management, involving the recommended manual weed control and plant spacing. Use of the LCC with rice is ready for wide‐scale promotion in Bangladesh.
Response of Soybean Grain Oil and Protein Concentrations to Foliar and Soil Fertilization
Authors: Haq Mazhar U. , Mallarino Antonio P.
Published: May 2005

Numerous studies investigated fertilization effects on soybean [Glycine max (L.) Merr.] grain yield, but few focused on oil and protein concentrations. This study determined fertilization effects on soybean grain oil and protein concentrations in 112 field trials conducted in Iowa from 1994 to 2001. Forty‐two trials evaluated foliar fertilization (N–P–K mixtures with or without S, B, Fe, and Zn) at V5–V8 growth stages. Seventy trials evaluated preplant broadcast and banded P or K fertilization (35 P trials and 35 K trials). Replicated, complete block designs were used. Foliar and soil P or K fertilization increased (P < 0.05) yield in 20 trials. Foliar fertilization increased oil concentration in one trial (1 g kg−1) and protein in one trial (5 g kg−1) but decreased protein in two trials (6 g kg−1). Phosphorus fertilization increased oil concentration in two trials (6 g kg−1) and protein in five trials (5 g kg−1) but decreased oil in five trials (4 g kg−1) and protein in two trials (6 g kg−1). Potassium fertilization increased oil in four trials (3 g kg−1) and protein in two trials (9 g kg−1) but decreased oil in two trials (4 g kg−1) and protein in two trials (11 g kg−1). Total oil and protein production responses to fertilization tended to follow yield responses. Fertilization increased oil production in 20 trials and protein production in 13 trials. Fertilization that increases soybean yield has infrequent, inconsistent, and small effects on oil and protein concentrations but often increases total oil and protein production.
Method and Timing of Rye Control Affects Soybean Development and Resource Utilization
Authors: Westgate Leslie R. , Singer Jeremy W. , Kohler Keith A.
Published: May 2005

Cover crops provide environmental and soil quality benefits, yet their adoption into production agriculture has been limited. This study was conducted to determine the influence of the growth stage and method of rye (Secale cereale L.) control on soybean [Glycine max (L.) Merr.] development and resource utilization. Fall‐planted rye was controlled the following spring using a stalk chopper (mechanical) or glyphosate (chemical) at the second‐node, boot, and anthesis growth stages near Boone, IA, in 2002 and 2003. Regrowth from mechanical rye control in 2002 depleted soil water until rye matured. Maximum light interception by soybean was reduced by as much as 43 and 30% in chemical and 51 and 23% in mechanical control compared with the no‐rye check in 2002 and 2003. Dry matter (DM) accumulation was reduced by as much as 267 and 907 g m−2 in chemical and mechanical control in 2002 compared with the check. In 2003, the range in DM accumulation was 242 g m−2. Rye delayed pod maturity in both years by as much as 7.9 d. Producers who adopt these methods of rye management can expect delayed soybean maturity and reduced DM accumulation.
Seed Yield and Oil Content of Cuphea as Affected by Harvest Date
Authors: Gesch Russ W. , Cermak Steven C. , Isbell Terry A. , Forcella Frank
Published: May 2005

Cuphea (Cuphea viscosissima Jacq. × C. lanceolata W.T. Aiton) can serve as an oilseed crop substitute for small‐ and medium‐chain triglycerides, which are in high demand for chemical manufacturing. Domesticated genotypes of cuphea show good potential for agricultural production, but their indeterminate growth may result in seed shatter if left in the field too long. Little information exists on when to harvest cuphea to obtain greatest seed yield and oil content. A study was conducted on a Barnes soil in west‐central Minnesota to determine the best time to harvest cuphea when sown at an optimum time in the spring. Harvests were taken at 1‐ to 2‐wk intervals from mid‐August through mid‐October during 2001 and 2002. Seed yields were greatest within a time period of about 20 d in late September to early October. Soon after a killing frost (≤−2°C), 5 October in 2001 and 9 October in 2002, yield declined sharply at a rate of about 10.6 kg ha−1 d−1, probably due to increased shattering. However, shattering due to mechanical harvesting was greater than that from natural causes. Total seed oil content also was influenced by harvest date. Across years, oil content averaged 247 g kg−1 in August, increasing to 304 g kg−1 by late September and thereafter. For greatest seed yield and oil content, the optimum time to harvest cuphea is in late September to early October in west‐central Minnesota. However, until more shatter‐resistant, determinate genotypes are developed, improved harvest management is needed to reduce shatter‐induced yield loss.
Response of No‐Till Soybean [Glycine max (L.) Merr.] to Timing of Preplant and Foliar Potassium Applications in a Claypan Soil
Authors: Nelson Kelly A. , Motavalli Peter P. , Nathan Manjula
Published: May 2005

Potassium availability in agronomic crops has recently decreased due to periodic drought conditions, soil compaction, reduced K applications, lower frequency of soil testing, and higher K fertilizer requirements because of increasing corn (Zea mays L.) yields and larger soybean [Glycine max (L.) Merr] acreage. Little research has evaluated the effects of foliar K applications on low to medium soil test K claypan soils, which are susceptible to drought and surface compaction. Field research was conducted in 2001 and 2002 to determine soybean response to foliar‐applied K fertilizer compared with a preplant application and evaluate the cost‐effectiveness of these treatments. Potassium fertilizer (K2SO4) was either broadcast‐applied at 140, 280, and 560 kg K ha−1 as a preplant application or foliar‐applied at 9, 18, and 36 kg K ha−1 at the V4, R1–R2, and R3–R4 stages of soybean development. Soybean grain yield increased 727 to 834 kg ha−1 when K was foliar‐applied at 36 kg ha−1 at the V4 and R1–R2 stage of development in 2001 and 2002. Foliar‐applied K at the R3–R4 stage of development increased grain yield but not as much as V4 or R1–R2 application timings. Treatment cost‐effectiveness ranked preplant K at 280 kg ha−1 = preplant K at 140 kg ha−1 > preplant K at 560 kg ha−1 = V4 or R1–R2 foliar‐applied at 36 kg ha−1. Foliar K did not substitute for preplant K in this research; however, foliar K may be a supplemental option when climatic and soil conditions reduce nutrient uptake from the soil.
Corn Yield, Nitrogen Use, and Corn Rootworm Infestation of Rotations in the Northern Corn Belt
Authors: Pikul Joseph L. , Hammack Leslie , Riedell Walter E.
Published: May 2005

Crop rotation may improve production efficiency and reduce fertilizer N requirements for corn (Zea mays L.). Objectives were to determine effect of rotation and N on corn yield, efficiency of water use (WUE) and N use (NUE), and corn rootworm (Coleoptera: Chrysomelidae) beetle populations (CR). Rotations (started in 1990) were continuous corn (CC), corn–soybean [Glycine max (L.) Merr.] (CS), and a 4‐yr rotation of corn–soybean–spring wheat (Triticum aestivum L.) companion‐seeded with alfalfa (Medicago sativa L.)–alfalfa hay (CSWA). Nitrogen treatments for corn were corn fertilized for a grain yield of 8.5 Mg ha−1 (highN), 5.3 Mg ha−1 (midN), and no N fertilizer (noN). Average yield (1992–2003) was greatest (p = 0.003) under CS and highN (7.0 Mg ha−1). Yield differences (p = 0.001) among rotations increased with decreased fertilizer N. Average (1992–2003) yield with noN fertilizer was 5.8 Mg ha−1 under CSWA, 4.5 Mg ha−1 under CS, and 2.8 Mg ha−1 under CC. Nitrogen use efficiency differed (p = 0.096) only under midN with CSWA = CS > CC. Soil water (upper 1.8 m) for corn measured on 1 June (average of N treatments) was 55, 54, and 45 cm for CC, CS, and CSWA, respectively. For CSWA under highN, available water limited yield in 3 of 6 yr. At highN, CR adult populations were greater under CS compared with CC and greater at higher N fertilizer levels within CC. Rotations have potential to improve production efficiency; however, there is potential for reduced corn yield after alfalfa due to less available soil water.
High Rates of Fe‐EDDHA and Seed Iron Concentration Suggest Partial Solutions to Iron Deficiency in Soybean
Authors: Wiersma John V.
Published: May 2005

Plants require a continuous supply of iron (Fe) to maintain proper growth. Low rates of Fe chelates applied to reduce Fe deficiency in soybean [Glycine max (L.) Merr.] probably do not satisfy this requirement. Our objective was to evaluate the effectiveness of high rates of Fe‐EDDHA in reducing Fe deficiency when applied to susceptible and resistant cultivars grown on soils where soybean historically has exhibited mild to severe Fe deficiency. Four cultivars (two resistant, two susceptible) and six rates of Fe‐EDDHA (0, 2.24, 4.48, 6.72, 8.96, and 11.20 kg ha−1) were evaluated at one location in 2002 and two locations in 2003. Severity of Fe deficiency varied markedly across environment and cultivars. Unifoliolate relative chlorophyll concentrations indicated that Fe deficiency can occur early in plant development and that planting seed Fe concentration (seed [Fe]) may be insufficient for early growth. Responses to higher rates of Fe‐EDDHA were environment and cultivar specific and occurred over an extended period, manifest at maturity. At lower rates (<6.72 kg Fe‐EDDHA ha−1), resistant cultivars exceeded susceptible cultivars in plant height, seed number, and grain yield, whereas at higher rates, susceptible cultivars often had values similar to resistant cultivars. Both resistant and susceptible cultivars exhibited linear responses to increasing rates when grown in harsh or intermediate environments, suggesting that even at very high rates of Fe‐EDDHA, Fe deficiency limited plant growth and grain yield. Seed [Fe] changed very little in response to added Fe. Plotting relative grain yield versus seed [Fe] for each environment illustrated the narrow range of seed [Fe] associated with wide ranges in relative yield and the large difference between resistant and susceptible cultivars regardless of relative yield.
Chromium (VI) separation from aqueous solution using anion exchange membrane
Authors: Pugazhenthi G. , Kumar Anil
Published: May 2005

The preparation is reported of a chemically modified crosslinked poly(methyl methacrylate–ethylene glycol dimethacrylate) (PMMA–EGDM) copolymer anion exchange ultrafiltration membrane on a macroporous clay support. This is obtained by nitrating a PMMA–EGDM membrane using NOx (a mixture of NO and NO2), which is further reduced to an amine group using hydrazine hydrate to form an anion‐exchange membrane (AEM). The membrane thus formed is characterized for its properties such as ion‐exchange capacity, membrane swelling, contact angle measurements, and membrane morphologies. The results show that the membrane becomes highly hydrophilic on the introduction of a charge and the separation experiments on the chromium (VI) salt solution show that the permeate flux (keeping the same rejection level of 90%) is considerably increased (by 100‐fold). The analysis of separation of Cr(VI) from its aqueous solution has been done by solving a two‐dimensional (in cylindrical coordinates) space‐charge model (SCM). A series solution of the nonlinear Poisson–Boltzmann equation has been generated, which leads to a considerable reduction in the computational time (from 15 h of batch time using the method reported earlier to 15 min for our method). The effective pore radius and wall potential of the unmodified and AEMs are evaluated by fitting the experimental data of the separation. The permeate flux calculated from this model matches well with the experimental values and a correlation is developed between the separation characteristic (rejection) and the wall charge developed by the chemical modification of the membrane. © 2005 American Institute of Chemical Engineers AIChE J, 2005
Pore diffusion simulation model of bimodal catalyst for Fischer‐Tropsch synthesis
Authors: Xu Bolian , Fan Yining , Zhang Yi , Tsubaki Noritatsu
Published: May 2005

The Fischer‐Tropsch (FT) synthesis reaction was conducted using bimodal catalyst in a slurry phase reactor. The bimodal catalyst was prepared from a bimodal support which was tailor‐made by introducing SiO2 sol directly into the large pores of a SiO2 gel pellet The bimodal catalyst exhibited significantly higher activity in the slurry‐phase Fischer‐Tropsch synthesis than in other unimodal catalysts. The support with a large surface area allowed a highly dispersed cobalt particle, and its large pore size improved the diffusion of reactants and products. The diffusion of reactants inside the catalyst pores was simulated, and the effects of pore structure and pore size on catalytic performances were consistent with the simulation results. © 2005 American Institute of Chemical Engineers AIChE J, 2005
Does female dominance facilitate feeding priority in black‐and‐white ruffed lemurs (Varecia variegata) in southeastern Madagascar?
Authors: Overdorff Deborah J. , Erhart Elizabeth M. , Mutschler Thomas
Published: May 2005

Although many Malagasy lemurs are thought to be female dominant and to have female feeding priority, to date the relationship between these behaviors has been rigorously established only in Lemur catta, and other ways that females might achieve feeding priority have not been examined closely. Erhart and Overdorff [International Journal of Primatology 20:927–940, 1999] suggested that one way female primates achieve feeding priority is to initiate and lead groups to food, thereby gaining access to the food first and positively influencing their food intake compared to other group members. Here we describe female dominance patterns and potential measures of feeding priority in two groups of black‐and‐white ruffed lemurs (Varecia variegata) that were observed over a 15‐month period in southeastern Madagascar. We predicted that the females would 1) be consistently dominant to males, 2) lead groups to food sources more often than males, and 3) have higher feeding rates compared to males when they arrived at food sources first. The results were dissimilar between the study groups. During the study, the oldest adult female in group 1 died. There was no evidence for female dominance in this group, and the remaining (likely natal) female did not lead the group more often, nor did she have a higher food intake than males. Group 1 dispersed shortly after the time frame reported here. In contrast, the resident female in group 2 was dominant to group males (based on agonistic interactions), led the group to food sources more often, and experienced a higher food intake when she arrived first at a food source. How these patterns vary over time and are influenced by the number of females in groups, group stability, food quality, and reproductive condition will be examined in future analyses. Am. J. Primatol. 66:7–22, 2005. © 2005 Wiley‐Liss, Inc.
Environmental enrichment to address behavioral differences between wild and captive black‐and‐white ruffed lemurs (Varecia variegata)
Authors: Kerridge Frances J.
Published: May 2005

I compared the behaviors of wild Varecia variegata living in a Malagasy rain forest with those of caged groups living in zoos in the United Kingdom in order to design environmental enrichment to encourage more natural behaviors. Comparisons were made between wild and captive animals in terms of activity budgets (instantaneously sampled at 1‐min intervals) and social and solitary behaviors, which were continuously recorded for focal individuals. I followed the same sampling protocol during behavioral enrichment experiments, with additional monitoring of the amount and type of food consumed, and with more detailed observations of feeding behavior. No significant differences were found in resting or moving between wild and captive V. variegata. However, captive V. variegata spent more time on self‐grooming and social behaviors, and less time feeding than wild V. variegata. There was also a lack of manual manipulation of food items. Behavioral enrichment experiments were carried out in which whole rather than chopped fruit was provided and presented in a more naturalistic manner. With this method of dietary presentation, manual manipulation of dietary items increased. Time spent feeding also increased significantly. Captive conservation breeding programs should not be wholly concerned with maintaining a diverse gene pool–they should also be concerned with conserving species‐typical behaviors, especially if they are to produce behaviorally intact captive animals that can be reintroduced to the wild with minimal training, financial resources, and loss of individuals. Am. J. Primatol. 66:71–84, 2005. © 2005 Wiley‐Liss, Inc.
Titelbild: “On Water”: Unique Reactivity of Organic Compounds in Aqueous Suspension (Angew. Chem. 21/2005)
Authors: Narayan Sridhar , Muldoon John , Finn M. G. , Fokin Valery V. , Kolb Hartmuth C. , Sharpless K. Barry
Published: May 2005

Reaktionen “an Wasser” bieten eine einfache Isolierung des Produkts und können erheblich schneller sein als dieselben Reaktionen in organischen Solventien. Das Titelbild zeigt den zeitlichen Verlauf einer En‐Reaktion zwischen (S)‐β‐Pinen und Diethylazodicarboxylat: Die unlöslichen Reaktanten treiben auf dem Wasser, während das Produkt unter die Wasserschicht absinkt und als farbloses Öl isoliert wird. Mehr über diese Reaktionen erfahren Sie in der Zuschrift von K. B. Sharpless et al. auf S. 3339 ff.
Cover Picture: “On Water”: Unique Reactivity of Organic Compounds in Aqueous Suspension (Angew. Chem. Int. Ed. 21/2005)
Authors: Narayan Sridhar , Muldoon John , Finn M. G. , Fokin Valery V. , Kolb Hartmuth C. , Sharpless K. Barry
Published: May 2005

Reactions “on water” offer ease of product isolation and may be substantially faster than the same reactions performed in organic solvents. The cover picture shows the time course of an ene reaction between (S)‐β‐pinene and diethyl azodicarboxylate performed on water. The insoluble reactants float on water, whereas the product descends under the water layer and is isolated as a colorless oil. For more details on these reactions, see the Communication by K. B. Sharpless and co‐workers on page 3275 ff.
Virtual laboratory manual for microscopic anatomy
Authors: Michaels John E. , Allred Kelly , Bruns Christina , Lim Wan , Lowrie D.J. , Hedgren Wade
Published: May 2005

Using digital technology, we have assembled a virtual laboratory manual (VLM) that is a Web‐based copy of our traditional laboratory manual. The VLM is used to enhance traditional laboratory instruction in histology. For each reference in the VLM to either a histological slide or an electron micrograph (EM), hyperlinks are included that download digital images derived from the students' glass slide sets or scanned EMs. The VLM serves as an atlas of digital images for concurrent study of similar sections by light microscopy during laboratory sessions. In addition, students can review the images from the VLM at remote locations. We have encouraged continued use of light microscopes in laboratories by basing the majority of practical examination identifications on analysis of marked histological slides that require students to use their own microscopes. The VLM provides the convenience of a Web‐based resource with high‐quality images, yet allows retention of the many excellent traditional aspects of our course. An example of a VLM laboratory on epithelium is available online (http://users.von.uc.edu/michaeje/VLM‐Epithelium/exLab4.pdf). Anat Rec (Part B: New Anat) 284B:17–21, 2005. © 2005 Wiley‐Liss, Inc.
A new way to teach an old topic: The cadaver‐based anatomy short course for high school students
Authors: Hubbard Christopher J. , Miller Jon S. , Olson Dan
Published: May 2005

An outreach program has been developed at the Department of Biological Sciences, Northern Illinois University (NIU), that offers an intensive short course in human gross anatomy to high school students and their teachers. Prior to the short course, the high school teachers attend a laboratory orientation, view the facilities, and then develop a syllabus suitable for the class needs. When the students arrive, they spend between 1 and 2 days rotating through five different work stations. Using their syllabus, they identify and learn the function of various structures on human cadavers and models. Evaluation and content testing of 143 students demonstrated a significant degree of enthusiasm and retention of the syllabus material at the end of the course. All teachers who participated in the program indicated that they wish to return the following year and new groups have already applied to attend. The results of the program demonstrate ways that universities can generate excitement about science and learning at the high school level. Anat Rec (Part B: New Anat) 284B:6–11, 2005. © 2005 Wiley‐Liss, Inc.