bluuebunny/crossref_metadata_2025 huggingface dataset:
Intraspecific Competition of an Insect‐Resistant Transgenic Canola in Seed Mixtures
Authors: Ramachandran Suresh , Buntin G.David , All John N. , Raymer Paul L. , Stewart C.Neal
Published: July 2010

Seed mixtures are recommended as a strategy to minimize or avoid having insects develop resistance to insect‐resistant transgenic crops. The objective of this study was to evaluate a canola, Brassica napus L., transgenic for a Bacillus thuringiensis cry1Ac gene for its resistance against diamondback moth, Plutella xylostella L., and for its competitive ability with nontransgenic canola in seed mixtures. Transgenic and nontransgenic canola were planted either as pure stands or in mixtures of 75:25, 50:50, and 25:75 in plastic trays in greenhouse experiments or in field experiments at three locations during the 1996 through 1998 field seasons. The trays and plots were either infested with diamondback moth neonates or left without any insect infestation. In diamondback moth‐infested treatments, transgenic plants had low levels of damage both as a pure stand and in mixtures. Nontransgenic plants in diamondback moth‐infested trays and plots suffered high levels of defoliation and produced less biomass and seed yield compared with transgenic plants. Relative crowding coefficient (RCC), a measure of competition between the two plant types, ranged from 0.6 to 1.1 in plots where there was no diamondback moth infestation and 1.1 to 12.8 in plots where there was diamondback moth infestation. No competitive advantage was observed for either plant type in seed mixtures when there was no diamondback moth infestation. Transgenic canola because of its high level of resistance was competitively superior in seed mixtures when there was diamondback moth infestation.
Yield Parameters as Affected by Introduction or Discontinuation of Catch Crop Use
Authors: Hansen Elly M⊘ller , Kristensen Kristian , Djurhuus J⊘rgen
Published: July 2010

A 24‐yr‐old permanent field trial on coarse sand (Orthic Haplohumod) under temperate coastal climate conditions was used to determine (i) the effect of introducing perennial ryegrass (Lolium perenne L.) as a catch crop on plots with a history of low input of organic matter, and (ii) the residual effect of long‐term use of ryegrass as a catch crop on main crop yield and N uptake. The catch crop (8–10 kg ha−1) was undersown in spring wheat (Triticum aestivum L.). From 1993 to 1996, four treatments were included: catch crop since 1968, catch crop since 1993, no catch crop, and catch crop until 1993. Each treatment was conducted at two previously established N rates (60 and 120 kg N ha−1 yr−1), which were subdivided into four new N rates (0, 60, 90, and 120 kg N ha−1 yr−1). Two years after introduction of the catch crop, yields were no longer different from yields with long‐term previous catch crop use. The residual effect of long‐term catch crop use on yield persisted for more than 4 yr. With previous long‐term use of a catch crop compared with no previous use, N fertilization could be reduced by 15 or 27 kg N ha−1 yr−1 at the 60 or 120 kg N ha−1 yr−1 rate, respectively, without yield reductions. The experiment shows that the use of ryegrass as a catch crop has the potential to benefit main crop yield and soil fertility.
Allelopathic Potential of Rice Hulls on Germination and Seedling Growth of Barnyardgrass
Authors: Ahn Joung Kuk , Chung Ill Min
Published: July 2010

Hull extracts from 91 cultivated rice cultivars (Oryza sativa L.) were used to determine their allelopathic potential on seed germination and seedling growth of barnyardgrass (Echinochloa crusgalli P. Beauv. var. oryzicola Ohwi). The allelopathic effects of various concentrations of hot and warm water hull extracts from selected cultivars were also investigated. In the initial screening the ‘SR31’ extract inhibited germination 59%. The length and dry weight of roots were more affected by hull extract than the shoots. The greatest total seedling length and dry weight inhibition was from the ‘Janganbyeo’ warm extracts and was 75 and 96%, respectively. Rice cultivars demonstrating significant allelopathic potential were compared using varying concentrations with a hot or warm extraction procedure. The two extraction procedures displayed different ultra violet (UV) absorption, pH, electrical conductivity (EC), and osmotic potential. Warm extracts exhibited a lower percentage absorbance in the UV range, higher percentage absorbance in the visible range, higher EC (S m−1) and osmotic potential (kPa), and showed lower pH than those of hot extracts. As concentration increased, the warm extracts had a greater inhibitory effect on barnyardgrass germination, seedling growth, weight, and caloric content than the hot extracts. The greatest inhibition occurred when the highest concentration (8 g L−1) warm water extract was applied. These results suggest that rice hull extracts may be a source of natural herbicide, and warm water may extract more allelochemicals than hot water. There may be genetic differences among rice cultivars for allelopathic potential on barnyardgrass. The breeding of rice cultivars with greater allelopathic potential may be possible.
Stubble Management Effects on Three Creeping Red Fescue Cultivars Grown for Seed Production
Authors: Meints Paul D. , Chastain Thomas G. , Young William C. , Banowetz Gary M. , Garbacik Carol J.
Published: July 2010

Nonthermal management to mechanically remove residue in creeping red fescue (Festuca rubra L.) seed crops has been associated with yield loss when compared with field burning. This 2‐yr field study was conducted to investigate the underlying causes for reduced seed yield potential under mechanical residue removal management compared with traditional burning. The effects of two stubble heights, 2.5 and 5.0 cm, complete mechanical stubble removal, and burning were measured on three cultivars of creeping red fescue stands during the first, second, and third year after establishment. Plant reserves for regrowth were reduced by an average of 47% over all cultivars when stubble was completely removed by burning or mechanically below 5.0 cm. Fall regrowth in stubble >2.5 cm in height ranged from 0.6 to 1.9 cm taller compared with treatments where stubble was completely removed. Fall tiller height showed a consistent negative relationship with fertile tiller production in the following spring. Rhizome development in ‘Shademaster’ and ‘Hector’, which produce many rhizomes, was reduced >30% when stubble was removed below 2.5 cm. Fertile tiller production, a major component of creeping red fescue yield potential, increased by >25% when stubble was removed by burning or mechanically to ground level in both Shademaster and Hector but was unaffected in ‘Seabreeze’, which produces few rhizomes. In seed production of creeping red fescue, stubble removal to the plant crown, particularly in cultivars producing many rhizomes, is crucial for maximizing seed yield potential.
Discriminating Crop Residues from Soil by Shortwave Infrared Reflectance
Authors: Daughtry Craig S.T.
Published: July 2010

Quantifying crop residue cover on the soil surface is important for evaluating the effectiveness of conservation tillage practices. Current methods of measuring residue cover are inadequate in characterizing the spatial variability of residue cover over large fields. The objectives of this research were to determine the spectral reflectance of crop residues and soils as a function of water content and to evaluate the limits of discrimination that can be expected. Spectral reflectances of corn (Zea mays L.), soybean [Glycine max (L.) Merr.], and wheat (Triticum aestivum L.) residues plus five diverse soils were measured over the 400‐ to 2400‐nm wavelength region at a wide range of moisture conditions in the laboratory. Reflectance factors for scenes with varying proportions of crop residues and soils were simulated. The spectra of dry crop residues displayed a broad absorption feature near 2100 nm, associated with lignin and cellulose, that was absent in spectra of soils. The relative depth of the cellulose–lignin absorption feature, defined as the cellulose absorption index (CAI), was positive for all crop residues, except those saturated with water. In contrast, all soils had negative CAI values. Water significantly altered reflectance spectra of wet crop residues, but it did not prevent the discrimination of crop residues from the soils using the CAI. The wide range of CAI values expected for dry and moist conditions makes quantification of crop residue cover feasible. This reflectance technique appears promising for field‐ and regional‐scale surveys of crop residue cover and conservation tillage practices.
Plant Growth and Nitrogenase Activity of Glyphosate‐Tolerant Soybean in Response to Foliar Glyphosate Applications
Authors: King C.Andy , Purcell Larry C. , Vories Earl D.
Published: July 2010

Glyphosate [N‐(phosphonomethyl)glycine] inhibits 5‐enolpyruvylshikimate‐3‐phosphate synthase, EC 2.5.1.19 (EPSPS), thereby blocking aromatic amino acid synthesis. While glyphosate‐tolerant (GT) soybean [Glycine max (L.) Merr.] contains resistant EPSPS, the N2‐fixing symbiont in soybean root nodules, Bradyrhizobium japonicum, does not contain a resistant enzyme, and glyphosate spray to GT soybean may interfere with the symbiotic relationship. Glyphosate‐tolerant soybean was treated with glyphosate at several different stages of development to evaluate N2 fixation, growth, and yield in a series of greenhouse, growth chamber, and field experiments. Early applications of glyphosate generally delayed N2 fixation and decreased biomass and N accumulation in the cultivar Terral TV5866RR (TV5866RR) harvested at 19 d after emergence (DAE), but plants had recovered by 40 DAE. The biomass and N content of GT soybean were also decreased by glyphosate in plants that were grown with available soil N. There were differences in sensitivity to glyphosate among GT cultivars, with biomass decreases in response to glyphosate ranging from 0 to 30% at 40 DAE for the most tolerant and sensitive cultivars that were evaluated. In growth chamber studies, N2 fixation was more sensitive to water deficits in glyphosate‐treated plants. In field studies, there was no measured effect of glyphosate on GT soybean at Fayetteville, AR where there was adequate soil water throughout the growing season. However, glyphosate tended to decrease biomass and seed yields under conditions of limited soil water at Keiser, AR.
Developmental Dynamics of Forage Chicory
Authors: Clapham William M. , Fedders James M. , Belesky David P. , Foster Joyce G.
Published: July 2010

Most studies on forage chicory (Cichorium intybus L.) are empirical, and very little information exists regarding the growth of chicory as it relates to development, productivity, persistence, and stand age. Development of uncut ‘Grasslands Puna’ chicory was studied in southern West Virginia on previously established plots at the Scott Farm in 1997 and 1998 and on 1‐yr‐old plantings at the Plumley Farm in 1998 and 1999. Chicory developmental parameters were modeled as a function of growing degree days (GDD) from Calendar Day 90 using a base of 5°C. On average, only 58% of the chicory plants became reproductive in any single growing season or location after the establishment year. Mean time to initiation of bolting and first open flower occurred consistently at approximately 400 and 1030 GDD, respectively, across locations and years. The indeterminate meristem of vegetative plants continuously produced leaves of relatively uniform mature area throughout the growing season. In comparison, the determinate meristem of reproductive plants rapidly expressed progressively smaller leaves on the main stem from initiation of bolting only until the time of first open flower. The developmental data herein create a framework with which to begin optimizing strategies for pasture and livestock grazing management of forage chicory.
Seasonal Variations in Hydrogen Cyanide Concentration of Three Lotus Species
Authors: Gebrehiwot Lulseged , Beuselinck Paul R.
Published: July 2010

Cyanogenic glucosides, generally considered antinutritional factors, are important defense molecules against predators and, in some cases, diseases. The objectives of this study were: (i) to determine the seasonal variations in hydrogen cyanide (HCN) concentration of three widely grown Lotus spp. and (ii) to assess the overall cyanogenic potential of the different plant components of a rhizomatous cultivar of broadleaf birdsfoot trefoil [Lotus corniculatus L.] (BFT). In this study, we used BFT cultivars Norcen and ARS‐2620, narrowleaf trefoil (L. glaber Mill.) germplasm ARS‐1207, and big trefoil (L. uliginosus Schkur.) germplasm ARS‐1221. The experiments were conducted in the field and greenhouse using a randomized complete block design. Significant seasonal variations in HCN concentrations in Norcen, ARS‐2620, and ARS‐1207 were observed. Hydrogen cyanide concentrations were greatest in spring and summer and least in winter. ARS‐1221 was acyanogenic. Of the three cyanogenic entries grown in the field study, ARS‐1207 had the greatest concentration of HCN, averaging 900 μg g−1 dry matter while Norcen and ARS‐2620 had similar levels of HCN. In the greenhouse, Norcen and ARS‐1207 had greater HCN concentrations than ARS‐2620. Partitioning of the rhizomatous BFT cultivar ARS‐2620 demonstrated that leaves and flowers produced the greatest concentration of HCN, five times as much as stems and ripe‐seed pods. Rhizomes, which are typically produced in winter and fall, did not exhibit HCN production. Seeds of Norcen and ARS‐2620 were acyanogenic, but ARS‐1207 seeds were weakly cyanogenic. However, as seeds germinated and seedlings formed cotyledons, Norcen, ARS‐2620, and ARS‐1207 exhibited HCN. Roots of all species were acyanogenic.
Spatial Legume Composition and Diversity across Seeded Landscapes
Authors: Harmoney Keith R. , Moore Kenneth J. , Brummer Edward C. , Burras C. Lee , George J. Ronald
Published: July 2010

Pastures typically have diverse landscapes, and resulting soil conditions and plant composition can vary within small area units. This study was performed to quantify the spatial variation in legume contribution to the plant community when seeded into established perennial cool‐season grass pastures. Pastures were interseeded with an 11‐legume mixture and divided into three stocking methods (continuous, rotational, and nongrazed), with each stocking method containing five landscape positions (summit, backslope, toeslope, opposite backslope, and opposite summit). Grass and legume components were sampled three times annually between 1996 and 1998. Backslopes had greater legume dry matter (DM) composition (161 g kg−1) than either summit (62 g kg−1) or toeslope positions (7 g kg−1), and total legume concentrations increased over years. Legume composition consisted mostly of red clover (Trifolium pratense L.), birdsfoot trefoil (Lotus corniculatus L.), and white clover (T. repens L.). Species richness and Shannon–Weiner diversity index (H’dm) for the legume functional group were also greatest on backslope landscape positions, especially in continuously and rotationally stocked pastures. Legume DM composition showed a positive linear relationship with legume species richness in continuous, rotational, and nongrazed pastures (r2 = 0.76). The H’dm showed a positive linear relationship with legume DM composition in only rotationally stocked paddocks (r2 = 0.88). The legume component at grazed backslope sites filled a niche left unoccupied by the grass component. Species and site recommendations for pasture improvement and management should be made based on landscape position and stocking method.
Cost of Steer Weight Gain to Rate of Supplementation with Ground Corn on Bermudagrass Pasture
Authors: Aiken G. E.
Published: July 2010

Cattle (Bos sp.) weight gain on bermudagrass [Cynodon dactylon (L.) Pers.] pastures declines in the middle to late grazing season regardless of forage supply. Nutrient supplementation with concentrates is an option for boosting average daily gain (ADG), but economic feasibility of this management is not clearly understood. A grazing experiment was conducted in 1998 and 1999 with yearling steers grazing bermudagrass to evaluate ADG and costs as amounts of supplemented ground corn (Zea mays L.) (0, 0.45, 1.35, and 2.25 kg steer−1 d −1) increased and to monitor seasonal changes in bermudagrass in vitro digestible dry matter and crude protein (CP) concentration. There was a curvilinear increase in ADG as supplementation was increased from 0 and 1.35 kg steer−1 d−1, but ADG stabilized between the 1.35‐ and 2.25‐kg rates. In vitro digestible dry matter and CP concentrations declined over the two grazing seasons, but CP concentration increased following the second application of N fertilizer in 1998 when rainfall was adequate for bermudagrass growth and N uptake. Cost of additional ADG from supplementation tended to be lowest for the 1.35 kg steer−1 d−1 supplementation rate over a range in corn costs from $90 to $250 Mg−1. The 1.35‐kg supplementation rate provided costs of additional ADG that were lower than break‐even costs for low ($1.32 kg−1 liveweight), intermediate ($1.77 kg−1 liveweight), and high ($2.20 kg−1 liveweight) cattle prices. Costs of additional ADG for the 0.45‐ and 2.25‐kg supplementation rates were lower than the break‐even costs for high cattle prices when corn costs were less than $170 and $190 Mg−1, respectively. Supplementation with ground corn at rates of 0.45 to 1.35 kg steer−1 d−1 can cost effectively enhance weight gain of yearling steers grazing bermudagrass.
Bahiagrass Production and Nutritive Value as Affected by Domestic Wastewater Residuals
Authors: Adjei Martin B. , Rechcigl Jack E.
Published: July 2010

Approximately 70% of Florida's biosolids is land‐applied with little supporting agronomic information. This experiment was conducted on bahiagrass (Paspalum notatum Flugge), on Pomona fine sand soil (sandy, siliceous, hyperthermic Ultic Alaquods), to compare the agronomic value of aerobically digested slurry biosolid, lime‐stabilized slurry biosolid, lime‐stabilized cake biosolid, and ammonium nitrate all applied to supply 90 or 180 kg N ha−1 vs. an unfertilized control. Forage production (3–5 Mg ha−1 yr−1) was similar for the ammonium nitrate and the slurries in 1998 and 1999, highest for the lime‐stabilized slurry in 2000, but always 30% lower for the cake biosolid due to the cake's lower N availability. The slurries and ammonium nitrate gave 50% or more forage and higher spring crude protein (CP) concentration (100–170 g kg−1) than the control (75–110 g kg−1). The CP was improved with ammonium nitrate in early spring, after which, there were no consistent differences in CP or in vitro organic matter digestion (460–600 g kg−1) among N sources. Tissue P (2.0–3.5 g kg−1), Ca (3.0–8.0 g kg−1), and Fe (40–250 mg kg−1) were increased by both biosolid slurries in the spring, whereas tissue Cu (6–15 mg kg−1) and Mn (10–100 mg kg−1) were elevated periodically only by the aerobically digested slurry. Forage was deficient in K and Mn in summer across treatments. Lime‐stabilized biosolid could boost bahiagrass production in Florida because it is lower in pathogens, inexpensive, and provides lime and organic matter.
Optimum Planting Procedures for Eastern Gamagrass
Authors: Aberle Ezra Z. , Gibson Lance R. , Knapp Allen D. , Dixon Phillip M. , Moore Kenneth J. , Brummer E. Charles , Hintz Roger
Published: July 2010

Eastern gamagrass (Tripsacum dactyloides L.) is a warm‐season, perennial bunch grass with great potential for use in grazing, cut forage, and conservation systems. Current recommendations for planting eastern gamagrass during the winter (November to February) are suitable for many areas but are inadequate in locales were the ground is frozen during most of this period. The objectives of this study were to determine the best combinations of planting date, planting depth, and seed stratification for eastern gamagrass in the northern range of its adaptation. Unstratified and stratified gamagrass seed was planted in mid‐August, late October–early November, mid‐April, mid‐May, and mid‐June at 2.5‐ and 5.0‐cm planting depths over two growing seasons. Planting in the late summer and fall resulted in better stand establishment than planting in the spring and early summer. The net seedling survival from plantings in April and May was 39 and 48% less than from summer and fall plantings of unstratified seed in 1999–2000 and 2000–2001, respectively. Seed stratification was beneficial to April plantings in only one year of the study and did not improve May or June plantings. At most planting dates, depth had little influence on final stand. Full stands contained at least one plant per 25 cm of row. Plantings producing stands above this level were the August, November, and June plantings in both years and the April planting of stratified seed in the first study year. While the June plantings resulted in adequate final stand numbers, stand establishment was delayed for more than 10 mo because most of the plants did not emerge until the following spring.
Soybean Yield Potential and Phenology in the Ultra‐Short‐Season Production System
Authors: Ishibashi Tetsuaki , Sneller Clay H. , Shannon Grover
Published: July 2010

Summer drought is a major yield limitation for soybean [Glycine max (L.) Merr.] in the Midsouth. Yield may be improved by matching crop development to periods of sufficient soil moisture, requiring a crop that matures by late July. Our objective was to evaluate early maturing lines for their ability to avoid drought and yield potential in the Midsouth. We evaluated maturity group (MG) 00 through I lines for yield and other traits in 2000 (222 lines) and 2001 (152 lines), planting irrigated plots in late April with final stands of >800000 plants ha−1. Sixty‐one lines selected from the 2000 trials were also grown in 2001. Many lines matured in <78 d from emergence and would avoid mid‐July or later droughts. In different environments, the average yield of this maturity class ranged from 1310 to 2712 kg ha−1 while the maximum yield of individual lines ranged from 2342 to 3594 kg ha−1. Other lines matured in 78 and 91 d and would avoid August droughts. In different environments, the average yield of this maturity class ranged from 2630 to 4128 kg ha−1 while the maximum yield of individual lines ranged from 3144 to 4676 kg ha−1. The potential of this ultra‐short‐season production system to produce a viable crop in less than 78 d may have significant implications as water supplies become more limited and expensive in the Midsouth and many other regions of the world.
Corn (Zea mays L.) Yield Prediction Using Multispectral and Multidate Reflectance
Authors: Chang Jiyul , Clay David E. , Dalsted Kevin , Clay Sharon , O'Neill Mary
Published: July 2010

Yield predictive models based on multiple sampling dates may explain more yield variability than models based on a single sampling date. This study determined the influence of two approaches (multiple regression of either soil and crop multispectral and multidate reflectance or variables developed during principal‐component analysis of reflectance data) on corn (Zea mays L.) yield predictions. Research was conducted in 1999, 2000, and 2001. Corn yield data from two 65‐ha fields were collected with a yield monitor, and crop and soil radiance [green, red, and near‐infrared (NIR) wavebands] was measured three times (April–May, July, and August–September). Relative radiance (reflectance) was determined by dividing the measured radiance by the radiance at invariant target. Stepwise multiple regression based on reflectance or principal components was used to develop predictive equations. Multiple‐regression models based on 2 yr of reflectance data were biased and provided poor estimates of yield whereas a model based on variables developed during principal‐component analysis of reflectance data measured in the spring and summer of 1999 and 200 was unbiased and explained 45% of the corn yield variability in 2001. Differences between these models were attributed to multicollinearity of the data. Models that included data from two or three sampling dates generally explained more yield variability than models that used only one sampling date. Reflectance measured early in the season provided information about soil water and color while reflectance measured in August and September provided information about plant conditions.
Nitrogen Dilution Curves and Nitrogen Use Efficiency During Winter–Spring Growth of Annual Ryegrass
Authors: Marino María A. , Mazzanti Arturo , Assuero Silvia G. , Gastal François , Echeverría Hernán E. , Andrade Fernando
Published: July 2010

For some species, mathematical models have been developed to describe tissue N dilution during crop growth and to estimate the plant N status applying the N nutrition index (NNI), the ratio between the actual tissue N concentration and the tissue N concentration needed to obtain the maximum instantaneous crop growth rate (critical tissue N concentration). The objectives of this work were (i) to obtain the critical N dilution curve (NDC) for annual ryegrass (Lolium multiflorum Lam.) corresponding to late winter and early spring growth, (ii) to compare it with NDCs obtained by other authors, (iii) to estimate the NNI for different levels of N fertilization, and (iv) to determine the apparent N use efficiency (NUE) and its components: N uptake efficiency (NUpE) and N conversion efficiency (NCE). Experiments were established in 1994 and 1995 to evaluate impacts of six N fertilization levels (0–250 kg N ha−1) applied at the end of winter. Fertilization significantly increased forage dry matter (DM) and N accumulation in both years. A fitted critical NDC [Ncr (g kg−1) = 40.73DM (t ha−1)−0.379; r2 = 0.69] presented lower values than a published reference NDC. The NNIs calculated using the critical NDC showed higher values at higher N fertilization levels. The validity of the critical NDC and the usefulness of the NNIs should be tested in further experiments. High NUE values were observed in both years (44.20 and 52.21 kg DM kg−1 N applied in 1994 and 1995, respectively) although NUpE and NCE values varied between experiments.
Greening of Agriculture for Long‐Term Sustainability
Authors: Francis Charles A.
Published: July 2010

Consolidation and growth of large corporations in U.S. agriculture are facing increasing scrutiny from a consumer public with growing awareness of environment issues. More people in society now question not only where food is grown and what types of practices impact the environment, but how the benefits are distributed. Although driven by short‐term economics in many purchasing decisions, consumers are asking whether we could continue our standard of living while maintaining the natural resource base and not polluting the environment. Agricultural corporations are responding to this consumer concern by greening some of their operations and especially greening their images. Is this a real conversion in methods and products or merely a “greenwashing” of the corporate image? Large corporations face economic, environmental, and social challenges in their quest for an improved image. Examples in five major areas illustrate the impacts of corporate agriculture: industrial organic food production, consolidation of farms, genetically modified organisms, global food systems, and unregulated capitalism and limited‐liability corporations. Each is related to structural conditions in agriculture, and each must be addressed by corporations that are serious about improving their images with consumers. To deal with these issues that impact both farmers and consumers, positive alternatives to conventional mainstream business approaches are discussed.
Influence of Planting Date on Aflatoxin Accumulation in Bt, non‐Bt, and Tropical non‐Bt Hybrids
Authors: Wiatrak P. J. , Wright D. L. , Marois J. J. , Wilson D.
Published: July 2010

Aflatoxin, produced by the fungus Aspergillus flavus Link, reduces the value of corn (Zea mays L.) and is usually associated with high temperatures, water stress, and insect damage. The objective of this study was to determine if Bt (Bacillus thuringiensis) corn hybrids or “tropical” germplasm could reduce aflatoxin accumulation with later planting dates. Aflatoxin accumulation (B1, B2, G1, and G2) in corn grain was evaluated on Bt, non‐Bt, and tropical non‐Bt hybrids and four planting dates (March, April, May, and June) from 1998 to 2000. Aflatoxin concentration in corn varied across years but generally decreased with later planting date. In 1998, aflatoxin accumulation was lower in Bt (314 ng g−1) than non‐Bt hybrids (634 ng g−1) but not different than tropical non‐Bt hybrid (470 ng g−1). However, aflatoxin contamination was lower from Bt hybrids (70 ng g−1) than from the tropical non‐Bt hybrid (259 ng g−1) but not different in non‐Bt hybrids (86 ng g−1) in 1999. In 2000, aflatoxin levels were low, and hybrid had no effect on aflatoxin concentration. Temperature and irrigation effects on aflatoxin accumulation were not consistent. Increased temperature and delayed harvest may lead to aflatoxin accumulation before harvest. However, precipitation may influence aflatoxin levels in some years. The results of this study indicate that aflatoxin accumulation in corn may be decreased with later planting date, and less accumulation in Bt than non‐Bt or tropical non‐Bt hybrids may be indirectly explained by insect reductions.
Management, Topographical, and Weather Effects on Spatial Variability of Crop Grain Yields
Authors: Kravchenko A. N. , Robertson G. P. , Thelen K. D. , Harwood R. R.
Published: July 2010

The quantitative characterization of spatiotemporal variability in crop grain yields is an important component for successful precision‐agriculture applications. The objective of this study was to analyze and quantify effects of management practices, topographical features, and weather conditions on spatial variability of crop yields. A one‐factor randomized complete block design experiment with six replications was established at the Long Term Ecological Research site in southwest Michigan in 1988. The treatments used in this study were two treatments with conventional chemical inputs (chisel plow and no‐till) and two organic‐based chisel‐plowed treatments with a winter leguminous cover crop (low chemical input and zero chemical input). The data consisted of corn (Zea mays L.)–soybean [Glycine max (L.) Merr.]–wheat (Triticum aestivum L.) yields collected via combine monitors from 1996 to 2001. We observed that stressful conditions, regardless of the stress origin, were associated with increase in the overall yield variability (coefficient of variation) as well as the small‐scale yield variability (variogram values at short lag distances and variogram slopes near the origin) with yields probably being more sensitive to the small‐scale variations in growth conditions due to soil and microtopographical differences. Coefficients of variation were as high as 45% in years with low precipitation and as low as 14% in years with above‐average precipitation. During the years with low precipitation, both the coefficients of variation and the small‐scale variability were often significantly higher in the zero chemical input treatment than in the treatments that received fertilizer inputs. The coefficients of variation and the small‐scale variability parameters also tended to be higher in corn stressed by antagonism from previous wheat crop in the no‐till treatment.
Gaseous Ammonia Losses from Urea Solutions Applied as a Foliar Spray to Various Grass Sods
Authors: Simpson D. M. H. , Melsted S. W.
Published: July 2010

The gaseous loss of NH3 from urea applied to plant sods was studied under laboratory conditions, using various grasses which had been grown in pots under greenhouse conditions. Spray applications of N15‐ and C14‐labeled urea solutions equivalent to 50, 100, and 150 pounds of N per acre were made to the potted plant samples which had been transferred to a bell‐jar apparatus. Care was taken to spray as much of the solution as possible directly on the plant foliage. The total amount of NH3 lost through volatilization, as measured over a period of 8 to 10 days, increased with increasing rates of application. Losses ranged from about 0.5 pounds per acre with a 50‐pound application to about 45 pounds with the 150‐pound application. A lag period of 2 to 3 days occurred before any measurable quantity of NH3 was lost from any of the plants, with the exception of bluegrass. The greatest amount of urea hydrolysis, as measured by C14O2 evolution, occurred during this 2‐ to 3‐day period. The amount of NH3 lost and the rate of urea hydrolysis were influenced somewhat by the type of sod to which urea was applied. In most cases, there apparently was little or no direct relationship between C14O2 evolution and the NH3 lost.
A Genesis Study of a Mohave Sandy Loam Profile
Authors: Buol S. W. , Yesilsoy M. S.
Published: July 2010

A Mohave sandy loam profile, representative of Red Desert soils, developed in the Avra Valley in southern Arizona was studied to determine its pedogenesis. A lithologic discontinuity was found at a depth of 60 inches which separates the soil profile from an underlying caliche layer. Only a weak and relatively recent carbonate accumulation is pedogenically associated with the present soil surface. Kaolinite and illite are the predominant clay minerals in the upper layer. Thin sections reveal few clay skins developed in the profile.
Physiological Activity of Hydrogen and Aluminum Clays and Resins
Authors: Polle E. O. , Jenny H.
Published: July 2010

Suspensions of H‐clay and Al‐H‐clay severely depleted excised barley roots of K, Mg, and Ca. Clays with exchangeable H ions were much more harmful than clays with exchangeable aluminum ions. The clear filtrates of these clay suspensions were no more effective than distilled water. Soybeans growing in columns of Al‐Ca resin had severely stunted side roots whereas plants in the adjacent sand columns that received the effluent from the resin exhibited a proliferating root system.
The Movement of DDT in Forest Soil Solutions
Authors: Riekerk H. , Gessel S. P.
Published: July 2010

DDT was sprayed at two rates on a gravelly forest soil. Periodic leachate collections from tension lysimeters placed under the forest floor and surface soil have been analyzed by gas chromatography. Only five micrograms/dm2 DDT leached through surface soil, independent of rates of application. This represented less than 1% of applied DDT, indicating a highly sensitive technique.
Acetylene‐Ethylene Assay Studies on Excised Root Nodules of Myrica asplenifolia L.
Authors: Fessenden R. J. , Knowles R. , Brouzes R.
Published: July 2010

The acetylene‐reducing activity of excised root nodules of Myrica asplenifolia L. [Comptonia peregrina (L.) Coult.] was measured on a large number of samples both in the field and in the laboratory. The apparent Km for acetylene was determined to be 0.006 atm and was not significantly different in the presence or in the absence of 0.8 atm of N2. Maximum activity was obtained between 26 and 30C and between 0.15 and 0.25 atm O2. No significant diurnal fluctuation in activity could be detected. High variation (coefficient of variation ca. 50%) between replicate samples of field‐collected nodules was a consistent feature of estimates of acetylene‐reducing activity over a range of sites, sample weights, and sample numbers. Therefore, field‐collected nodules are unsuitable for physiological experiments unless the effect of the treatments on acetylene‐reducing activity is large. In ecological studies where field‐collected nodules must be used, extensive sampling is required to permit reliable estimates of the activity. The ratio of the rate of ethylene produced from acetylene to the rate of 15N2 incorporated was measured by exposing individual nodule samples sequentially to 15N2, then acetylene. The mean ratio for 24 samples was 3.14 ± 0.30.
Sampling Tool for Taking Undisturbed Soil Cores
Authors: Robertson W. K. , Pope P. E. , Tomlinson R. T.
Published: July 2010

A tool is described that can be attached to a commercially available soil sampler3 that will take undisturbed soil cores 15 cm diam and 75 cm long in corlon4 tubes. The tubes were sealed at the bottom with a sheet of plastic in which drainage tubes were inserted. Leaching studies could be made when tubes containing cores were placed on racks in the greenhouse. Further refinements include suction cups at regular intervals in the side of the column for nutrient movement studies and porous plates at the top and/or the bottom to make moisture tension in the profile similar to natural conditions.
Identification of Clay Minerals in Soil: The Effect of Sodium‐Pyrophosphate
Authors: Omueti J. A. I. , Lavkulich L. M.
Published: July 2010

The effect of Na4P2O7 on soil clay minerals, layer silicate clays, and chloritized montmorillonite (synthetic) was investigated by x‐ray diffraction. The soil samples were treated with 30% H2O2, boiled, and water‐washed by centrifugation. The resulting organic‐free solids were dispersed as follows: shaken with 0.1 M Na4P2O7 · 10H2O for 16 h only; treated with dithionite‐citrate‐bicarbonate (DCB); and treated with DCB followed by 0.1 M Na4P2O7 · 10H2O. The 0.1 M Na4P2O7 · 10H2O treatment caused the peak at 1.403 nm in the soil samples to become enlarged, sharp, and move to 1.339 nm. Other sharp peaks were also produced at 0.666, 0.637, 0.590, 0.561, 0.444, and 0.334 nm. These peaks were not observed in the x‐ray diffractograms of kaolinite and halloysite, but those of montmorillonite, chloritized montmorillonite, and chlorite were very similar to those of the soils. Heat treatment at 100°C destroyed the 0.637‐, 0.590‐, and 0.561‐nm peaks in some of the soil clay samples. At 300° the remaining peaks disappeared suggesting that sharp peaks resulting from the 0.1 M Na4P2O7 treatment may be the result of mineral hydration. Some of these new peaks from 0.1 M Na4P2O7 treatment of soil clays, the 0.334‐nm peak for example, can be mistaken as indicative of quartz in samples that do not contain this mineral. Thus the continued use of this reagent for mineralogical studies is not recommended.
Some Medicinal Plants among the Tribes of Chhatarpur District (M.P.) India
Authors: Arjariya Amita , Chaurasia Kalpana
Published: July 2010

The Chhatarpur District in central India is home to numerous herb species. The agro-climatic conditions prevailing in the region provide an ideal habitat for the natural growth of a variety of plants and herbs, which provide raw materials for pharmaceutical, phytochemical, food, flavoring and cosmetic industries. The paper provides information on 58 medicinal plants used by the Gond, Bhil and Bediya tribes of Chhatarpur district of Madhya Pradesh, India, for the treatment of various diseases. Traditional medicine remains an integral part of the health system in this area. Medicinal plants of forest origin hold great promise to enhance the health and livelihoods of the forest dwellers. Key words: Ethno medicinal, tribes, medicinal plants, traditional uses, diseases. DOI: 10.3126/eco.v16i0.3472ECOPRINT 16: 43-50, 2009
Richard Bradley (c. 1688–1732): an annotated bibliography, 1710–1818
Authors: EDMONDSON JOHN
Published: July 2010

Richard Bradley FRS (c. 1688–1732) was the author of the first illustrated book on succulent plants, Historia plantarum succulentarum (1716–1727), and editor of the first British horticultural journal. This bibliography, containing 140 main entries, attempts to list each of the separate editions (including translations) of his many works. It includes titles translated or adapted from French, Greek and German authors, along with some anonymous works written in his style.
Microwave‐Assisted Dieckmann Reaction: Efficient One‐Step Synthesis of 2‐Aroylbenzofuran‐3‐ols
Authors: Zhou Zhong‐Zhen , Deng Yan‐Hong , Jiang Zhi‐Hong , Chen Wen‐Hua
Published: July 2010

This paper describes the first efficient one‐step synthesis of 2‐aroylbenzofuran‐3‐ols from the microwave‐assisted Dieckmann reaction of substituted methylsalicylates with 2‐bromo‐1‐aroylethanones in alkaline aprotic solvents. This method features excellent yields, short reaction time (15 min) and high functional group compatibility, making it an efficient and practical approach for the synthesis of 2‐aroylbenzofuran‐3‐ols.
Continuous screening system for inhibited enzyme catalysis: A membrane reactor approach
Authors: Lyagin Evgenij , Drews Anja , Bhattacharya Subhamoy , Ansorge‐Schumacher Marion B. , Kraume Matthias
Published: July 2010

The screening of catalysts, substrates or conditions in the early stages of bioprocess development requires an enormous number of experiments and is a tedious, expensive and time‐consuming task. Currently available screening systems can only be operated in batch or fed‐batch mode, which can lead to severe misinterpretations of screening results. For example, catalysts that are inhibited by substrates or accumulating products will be excluded from further investigations in the early stages of process development despite the fact that they might be superior to other candidates in a different operational mode. Important and advantageous properties such as turnover stability can also be overshadowed by product inhibition. The aim of this study was to develop a novel screening system that enables continuous feeding of substrates and continuous removal of products. A prototype based on the membrane reactor concept was designed and operated for a model reaction, the hydrolysis of cellulose.
Efficacy, safety, and tolerability of overnight switching from immediate‐ to once daily extended‐release pramipexole in early Parkinson's disease
Authors: Rascol Olivier , Barone Paolo , Hauser Robert A. , Mizuno Yoshikuni , Poewe Werner , Schapira Anthony H.V. , Salin Laurence , Sohr Mandy , Debieuvre Catherine ,   for the Pramipexole Switch Study Group
Published: July 2010

The aim of this article is to test the feasibility, in early Parkinson's disease (PD), of an overnight switch from immediate‐release (IR) pramipexole to a new once‐daily extended‐release (ER) formulation. Nonfluctuating patients on pramipexole IR three‐times daily, alone or with levodopa, for early PD were randomly switched overnight to double‐blind IR three‐times daily (N = 52) or ER once‐daily (N = 104) at initially unchanged daily dosage. Successful switching (defined as no worsening >15% of baseline UPDRS II+III score and no drug‐related adverse event withdrawal) was assessed at 9 weeks, after optional dosage adjustments (primary endpoint), and at 4 weeks, before adjustment. Other secondary endpoints included adjusted mean changes from baseline in UPDRS scores and proportion of responders based on Clinical or Patient Global Impression (CGI/PGI). Absolute difference between percentage of successful switch to ER versus IR was tested for ER noninferiority, defined as a 95% confidence‐interval lower bound not exceeding −15%. At 9 weeks, 84.5% of the ER group had been successfully switched, versus 94.2% for IR. Noninferiority was not demonstrated, with a difference of −9.76% (95% CI: [−18.81%, +1.66%]). At 4 weeks, 81.6% of the ER group had been successfully switched, versus 92.3% for IR, a difference of −10.75% (95% CI: [−20.51%, +1.48%]). UPDRS changes and CGI/PGI analyses showed no differences between the groups. Both formulations were safe and well tolerated. Pramipexole ER was not equivalent to IR, but the difference was marginal. The fact that >80% of the patients successfully switched overnight at unchanged dosage shows that this practice was feasible in most patients. © 2010 Movement Disorder Society
Rapid motion correction in MR‐guided high‐intensity focused ultrasound heating using real‐time ultrasound echo information
Authors: de Oliveira Philippe Lourenço , de Senneville Baudouin Denis , Dragonu Iulius , Moonen Chrit T. W.
Published: July 2010

The objective of this study was to evaluate the feasibility of integrating real‐time ultrasound echo guidance in MR‐guided high‐intensity focused ultrasound (HIFU) heating of mobile targets in order to reduce latency between displacement analysis and HIFU treatment. Experiments on a moving phantom were carried out with MRI‐guided HIFU during continuous one‐dimensional ultrasound echo detection using separate HIFU and ultrasound imaging transducers. Excellent correspondence was found between MR‐ and ultrasound‐detected displacements. Real‐time ultrasound echo‐based target tracking during MR‐guided HIFU heating is shown with the dimensions of the heated area similar to those obtained for a static target. This work demonstrates that the combination of the two modalities opens up perspectives for motion correction in MRI‐guided HIFU with negligible latency. Copyright © 2010 John Wiley & Sons, Ltd.
Interchromatin granule clusters of the scorpionfly oocytes contain poly(A)+ RNA, heterogeneous ribonucleoproteins A/B and mRNA export factor NXF1
Authors: Batalova Florina M , Bogolyubov Dmitry S , Parfenov Vladimir N
Published: July 2010

IGCs (interchromatin granule clusters), or nuclear speckles, are one of the most universal subnuclear organelles of eukaryotic cells. We have used insect oocytes to study the possible association of poly(A)+ RNA and some factors involved in mRNA export with IGCs. Oogenesis of the mecopteran, Panorpa communis, used as a model object, is characterized by a strict cessation of oocyte genome transcription activity towards the end of oocyte growth. Our previous studies on P. communis oocyte nuclei have shown that oocyte IGC counterparts in this species are very unusual, both in morphology and molecular composition, compared with the typical IGCs of mammalian somatic cells traditionally used as a model system. We have now used microinjections of 2′‐O‐Me(U)22 probes conjugated with the fluorochrome TAMRA to localize poly(A)+ RNA in IGCs. RNA export proteins were also detected by immunofluorescent/confocal and immunogold labelling electron microscopy. We found that poly(A)+ RNA, hnRNPs A/B and NXF1 mRNA export factors are located in IGCs regardless of the transcriptional status of the nucleus. Our data support the idea of IGCs as universal and conserved nuclear domains that serve not only as splicing factor reservoirs, but also take part in mRNA retention and export.
Properties of knotted ring polymers. II. Transport properties
Authors: Mansfield Marc L. , Douglas Jack F.
Published: July 2010

We have calculated the hydrodynamic radius Rh and intrinsic viscosity [η] of both lattice self-avoiding rings and lattice theta-state rings that are confined to specific knot states by our path-integration technique. We observe that naive scaling arguments based on the equilibrium polymer size fail for both the hydrodynamic radius and the intrinsic viscosity, at least over accessible chain lengths. (However, we do conjecture that scaling laws will nevertheless prevail at sufficiently large N.) This failure is attributed to a “double” cross-over. One cross-over effect is the transition from delocalized to localized knotting: in short chains, the knot is distributed throughout the chain, while in long chains it becomes localized in only a portion of the chain. This transition occurs slowly with increasing N. The other cross-over, superimposed upon the first, is the so-called “draining” effect, in which transport properties maintain dependence on local structure out to very large N. The hydrodynamic mobility of knotted rings of the same length and backbone structure is correlated with the average crossing number X of the knots. The same correlation between mobility and knot complexity X has been observed for the gel-electrophoretic mobility of cyclic DNA molecules.