bluuebunny/crossref_metadata_2025 huggingface dataset:
Soft Red Winter Wheat (Triticum aestivum) Cultivar Response to Metribuzin
Authors: Schroeder Jill , Banks Philip A. , Nichols Robert L.
Published: May 2019

Greenhouse and field experiments, at two locations in Georgia, evaluated the tolerance of several soft red winter wheat cultivars (Triticum aestivumL.) to postemergence applications of metribuzin [4-amino-6-(1,1-dimethylethyl)-3-(methylthio)-1,2,4-triazin-5(4H)-one]. In the greenhouse, none of the cultivars growing in pots tolerated a 0.6 kg ai/ha treatment of metribuzin applied at the two-to three-tiller, six- to nine-tiller, or early-stem elongation growth stages. In nutrient culture, ‘McNair 1003’ was more tolerant to a 0.15 μg/ml concentration of metribuzin than other cultivars. Significant injury and yield reductions of wheat cultivars treated in the field with 0.6 and 1.1 kg/ha of metribuzin occurred. Differences between the cultivars were not uniform over all experiments. Increased injury was accompanied by higher rainfall and low temperatures subsequent to application. None of the wheat cultivars evaluated in the field experiments was injured by the 0.3 kg/ha rate of metribuzin. Acceptable selective weed control was obtained with this rate, indicating that metribuzin could be used in these soft red winter wheat cultivars.
Germination of Cutleaf Groundcherry (Physalis angulata), Smooth Groundcherry (Physalis virginiana), and Eastern Black Nightshade (Solanum ptycanthum)
Authors: Thomson Craig E. , Witt William W.
Published: May 2019

Factors that govern the germination of cutleaf groundcherry (Physalis angulataL. # PHYAN), smooth groundcherry [Physalis virginianavar.subglabrata(Mackenz. and Bush) Waterfall # PHYSU], and eastern black nightshade (Solanum ptycanthumDun. # SOLPT) were evaluated. Maximum germination of all three species occurred at a constant 30 C or alternating temperature regimes that included 30 C. Seed of all species germinated in light and dark, but germination was reduced in the dark. Germination and seedling vigor of all species decreased as substrate pH decreased. Cutleaf groundcherry seed were slightly less sensitive than seed of other species to simulated moisture stress. All species produced 90% or more viable seed by 8 weeks after anthesis.
Expression in Plants of a Bacterial Gene Coding for Glyphosate Resistance
Authors: Thompson Gregory A. , Hiatt William R. , Facciotti Daniel , Stalker David M. , Comai Luca
Published: May 2019

The target site of glyphosate [N-(phosphonomethyl)glycine] inhibition in plants and bacteria is 5-enolpyruvylshikimate 3-phosphate (EPSP) synthase. Our strategy for developing glyphosate-resistant crops has been to genetically engineer plants with a gene that codes for EPSP synthase with low sensitivity in glyphosate. We cloned such a gene from thearoAlocus of a glyphosate-resistant mutagenized strain ofSalmonella typhimurium.The enzyme encoded by this gene has a single amino acid change resulting in lower affinity for glyphosate and higher affinity for substrates than either plant or wild-type bacterial counterpart. A chimaeric gene containing the mutantaroAgene behind the octopine synthase promoter was constructed and integrated intoAgrobacteriumT-DNA vectors. Analysis of gall tissue fromBrassica campestrisL. (turnip rape) infected withA. tumefaciensK12 containing this chimaera showed mRNA and protein expressed from the bacterial gene; 50% of the total EPSP synthase activity present had kinetic properties of the mutant bacterial enzyme. Tobacco (Nicotiana tabacumL. ‘Xanthi′) plants have been regenerated from cocultivation withA. rhizogenescontaining the same construct; analysis indicates expression of the gene and enhanced tolerance to glyphosate.
Effects of Johnsongrass (Sorghum halepense) Density on Sugarcane (Saccharum officinarum) Yield
Authors: Ali Ahmed D. , Reagan T. Eugene , Kitchen Lynn M. , Flynn Jeff L.
Published: May 2019

The effects of johnsongrass [Sorghum halepense(L.) Pers. # SORHA] infestations were determined during a 2-yr study on sugarcane (Saccharum officinarumL. ‘CP-65-357’) yield. Both cane and sugar yields were lower (36 and 31%, respectively) in plots heavily infested with johnsongrass than in weed-free plots. Sugarcane yields were inversely influenced by johnsongrass equivalents (the sum of the values obtained by multiplying the number of clumps by their corresponding importance value for each plot). In 1983, both johnsongrass standing crop and johnsongrass equivalents correlated negatively with cane yield much better than any other factor combinations, while in 1984, the same was true for stalk population. Substantial yield reductions from johnsongrass interference were observed at johnsongrass infestation levels higher than 15 to 35%.
Influence of Adjuvants and Application Variables on Postemergence Weed Control with Bentazon and Sethoxydim
Authors: Harrison S. Kent , Wax Loyd M. , Bode Loren E.
Published: May 2019

Experiments were conducted at Urbana, IL, in 1983 and 1984 to determine the effect of adjuvants, adjuvant rate, and carrier volume on postemergence weed control with bentazon [3-(1-methylethyl)-(1H)-2,1,3-benzothiadiazin-4(3H)-one 2,2-dioxide] and sethoxydim {2-[1-(ethoxyimino)butyl]-5-[2-(ethylthio)propyl]-3-hydroxy-2-cyclohexen-1-one} in soybeans [Glycine max(L.) Merr. ‘Williams’]. Little difference was observed between a petroleum oil:emulsifier blend (83:17, v/v) (POC) and a soybean oil: emulsifier blend (85:15, v/v) (SBOC) in enhancing control of velvetleaf (Abutilon theophrastiMedik. # ABUTH) with 0.6 or 1.1 kg ai/ha bentazon. Application of bentazon in a carrier volume of 94 L/ha provided velvetleaf control equivalent to that applied in 187 L/ha. Increasing the adjuvant rate from 2.3 to 11.7 L/ha increased visible soybean injury but had no effect on velvetleaf control with bentazon. Control of giant foxtail (Setaria faberiHerrm. # SETFA) with 0.1 kg ai/ha sethoxydim was enhanced more by POC than by SBOC. Phytotoxicity of sethoxydim was not altered by changes in carrier volume or adjuvant rate under conditions of adequate soil moisture in 1983. Under limiting soil moisture in 1984, giant foxtail control with sethoxydim increased slightly when the adjuvant rate was increased from 4.6 to 11.7 L/ha, and carrier volume was increased from 47 to 187 L/ha.
Effect of Trifluralin Soil Metabolites on Soybean (Glycine max) Growth and Yield
Authors: Koskinen William C. , Oliver James E. , McWhorter Chester G. , Kearney Philip C.
Published: May 2019

The effects of twelve soil metabolites of trifluralin [2,6-dinitro-N,N-dipropyl-4-(trifluoromethyl)benzenamine] on soybean [Glycine max(L.) Merr.] growth, yield, and seed oil and protein content were determined. The metabolites included oxidative dealkylated, reduced nitro group, benzimidazole, azoxy, azo, oxidized, and hydroxylated derivatives of trifluralin. When applied at 0.22 kg ai/ha and incorporated 7.5 cm deep, no individual metabolite had a significant adverse effect on growth or yield. Three of the metabolites significantly decreased seed oil content and two of the metabolites significantly increased seed protein content. These effects are not considered important in that the differences, while statistically significant, are very small. Also, the amounts of metabolites applied greatly exceeded those expected to be found after many years of continuous use of trifluralin. Potential accumulation of individual metabolites from long-term use of trifluralin does not appear to adversely affect soybean growth, yield, or quality.
The Degradation and Bioactivity of Metolachlor in the Soil
Authors: Braverman Michael P. , Lavy Terry L. , Barnes Clyde J.
Published: May 2019

In bioassays, rice (Oryza sativaL.) recovery from metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl)acetamide] injury tended to be slower in flooded rice, but was not significantly different from the recovery rate in a nonflooded rice. In soils treated with 1 ppm (w/w) metolachlor and incubated in constant-temperature chambers, the half-life of metolachlor was shorter at 40 C than at 30 C. The degradation rate of metolachlor was not significantly correlated with declining moisture potentials in the range of −30 to −80 kPa. The CO2evolution from metolachlor-treated soil was negatively correlated with incubation time and positively correlated to declining moisture levels. In a field study, metolachlor, as determined by bioassay, was mobile in a Taloka silt loam soil profile. After being incorporated to 7.5 cm, it became evenly distributed in the top 15 cm of the soil profile within 18 days. Metolachlor adsorption was positively correlated with clay and organic carbon content.
Inhibited Mitotic Entry is the Cause of Growth Inhibition by Cinmethylin
Authors: El-Deek Mahmound H. , Hess F. Dan
Published: May 2019

The herbicide cinmethylin {exo-1-methyl-4-(1-methylethyl)-2-[(2-methylphenyl)methoxy]-7-oxabicyclo [2.2.1] heptane} inhibited oat (Avena sativaL. ‘Porter’) root growth during the first 6 h of treatment at a concentration of 6.7 × 10-8M. A concentration of 1 × 10-8M cinmethylin inhibited root growth within 12 to 18 h. Inhibition of shoot growth was less sensitive, but was inhibited by 36 to 48 h after treatment with 1 × 10-7M and by 12 to 24 h after treatment with 1 × 10-5M cinmethylin. Cinmethylin concentrations of 1 × 10-5M and lower did not inhibit cell elongation in isolated oat coleoptiles during a 24-h exposure. Mitotic frequency in oat root tips was reduced after 12 h of treatment with 1 × 10-7M cinmethylin. The frequency of all stages of mitosis (prophase, metaphase, and anaphase + telophase) was reduced. Concentrations of 1 × 10-6M cinmethylin resulted in nearly complete arrest (87% inhibition) of mitosis. These data suggest cinmethylin inhibits growth by inhibiting entry of cells into mitosis. The cause of mitotic arrest is unknown; however, the mechanism appears to be different from other herbicides known to inhibit mitosis.
Soil Solution and Mobility Characterization of Imazaquin
Authors: Goetz Andrew J. , Wehtje Glenn , Walker Robert H. , Hajek Ben
Published: May 2019

Imazaquin {2-[4,5-dihydro-4-methyl-4-(1-methylethyl)-5-oxo-1H-imidazol-2-yl]-3-quinolinecarboxylic acid} sorption and mobility were studied in five Alabama soils ranging from sandy loam to clay. Techniques included thinlayer soil chromatography, batch equilibrium, and soil solution recovery. Imazaquin was mobile in all soils with Rfvalues of 0.8 to 0.9. Sorption based on batch equilibrium was minimal with Kdvalues ranging from 0.001 to 0.21. The soil solution recovery technique was used to evaluate imazaquin sorption in each soil as influenced by imazaquin concentration, wetting and drying, and pH. As herbicide concentration added to the soils was increased from 0.1 to 10 mg/kg, the amount of14C-imazaquin in soil solution increased. Temporarily drying each soil to 25 or 50% of field capacity resulted in maximum sorption of imazaquin. Lowering the pH enhanced sorption in all soils such that the amount of imazaquin in solution ranged from 38 (low pH) to 100% (high pH). Soil sorption appeared to be governed by the pH-dependent charge surfaces from aluminum and iron oxyhydroxides (specifically hematite and gibbsite) and kaolinite.
Germination Responses to Temperature of Atrazine-Resistant and -Susceptible Biotypes of Two Pigweed (Amaranthus) Species
Authors: Weaver Susan E. , Thomas A. Gordon
Published: May 2019

Percent germination and germination rates of seeds of atrazine (6-chloro-N-ethyl-N′-(1-methylethyl)-1,3,5-triazine-2,4-diamine)-resistant and -susceptible biotypes of redroot pigweed (Amaranthus retroflexusL. # AMARE) and Powell amaranth (A. powelliiS. Wats. # AMAPO) from southern Ontario were compared in petri dishes using a 100-cell germination plate. The plate provided 100 separately controlled, alternating temperature combinations ranging from 0 to 45 C in increments of 5 C. The experiment was conducted under alternating light and dark conditions for 21 days and under constant dark conditions for 7 days. Initial seed viabilities exceeded 90% for all four biotypes. Under alternating light and darkness, the resistant biotype of Powell amaranth had significantly lower total germination and a slower rate of germination than the susceptible biotype, whereas the biotypes of redroot pigweed did not differ in germination response. Germination rate and total germination were positively correlated for all four biotypes. In constant darkness, the atrazineresistant biotypes of both species had significantly lower germination percentages compared to the susceptible biotypes. In general, percent germination of Powell amaranth was greater than that of redroot pigweed for day and night temperatures <25 C, whereas redroot pigweed had greater germination at higher temperatures. Greater seed dormancy of the resistant biotypes under some light and temperature combinations may have implications for the persistence of resistant populations in the field.
Evaluation of Ethofumesate for Annual Bluegrass (Poa annua) and Turfgrass Tolerance
Authors: Coats G. Euel , Krans Jeff V.
Published: May 2019

Field and greenhouse studies were conducted to evaluate annual bluegrass (Poa annuaL. # POAAN) control and phytotoxicity of ethofumesate [(±)-2-ethoxy-2,3-dihydro-3,3-dimethyl-5-benzofuranyl methanesulfonate] to selected warm- and cool-season turfgrass species. Annual bluegrass control in non-overseeded dormant hybrid bermudagrass [Cynodon dactylon(L.) Pers. XC. tranvaalensisBurtt-Davy Tifgreen’ # CYNDA] was 75% or greater with at least two ethofumesate applications at monthly intervals starting in December. Tifgreen bermudagrass spring growth was delayed with more than two applications of ethofumesate at 1.1 kg ai/ha, or when the second application was made after January. Under greenhouse conditions the growth of both Tifgreen and Tifdwarf bermudagrass was less when treated with ethofumesate. Stand and shoot growth of 29 cultivars of ryegrass (Loliumspp.), bluegrass (Poaspp.), bentgrass (Agrostisspp.), and red fescue (Festuca rubraL. # FESRU) were reduced by ethofumesate at 1.1 kg/ha as a preemergence or split (0.5 kg/ha preemergence + 0.5 kg/ha postemergence) application. Postemergence applications were less phytotoxic to cool-season turfgrasses than preemergence applications. Perennial ryegrass stands were generally not reduced by postemergence application of ethofumesate at 1.1 kg/ha. However, shoot growth of perennial ryegrass was reduced.
Herbicide-Induced Microbial Invasion of Plant Roots
Authors: Greaves Michael P. , Sargent John A.
Published: May 2019

Although herbicides are designed to have no effects on the crops in which they are used, crop damage can occur, especially when overdoses are used or if chemicals are applied at an inappropriate time. Usually the resulting damage is recognized as foliar symptoms but roots may be severely affected as well.
Translocation of Clopyralid and 2,4-D in Canada Thistle (Cirsium arvense)
Authors: Turnbull G. C. , Stephenson G. R.
Published: May 2019

The translocation and root exudation of leaf-applied sublethal concentrations of14C-labeled clopyralid (3,6-dichloropicolinic acid) and14C-labeled 2,4-D [(2,4-dichlorophenoxy)acetic acid] were compared in Canada thistle [Cirsium arvense(L.) Scop. var.horridumWimm. and Grab. ♯ CIRAR] at the rosette stage over a period of 9 days. The rate of absorption and export of14C out of the treated leaf was similar for both herbicides. However, the distribution of the herbicides throughout the plant was very different. After 9 days, 15 vs. 3% of the applied14C from14C-clopyralid vs.14C-2,4-D, respectively, was isolated from the foliage of the treated leaf. In the roots, twice as much14C was recovered from the14C-clopyralid treatments as from the14C-2,4-D treatment at all sampling times, with 33 vs. 15% being recovered, respectively, after 9 days. When the plants were grown hydroponically, 20% of the14C-clopyralid vs. 48% of the14C-2,4-D was recovered in the nutrient solution during a 9-day period. No metabolites of either herbicide were recovered from the foliage, root system, or nutrient solution. Large differences in translocation of these herbicides may account for the unequal toxicity to young Canada thistle plants.
Interference and Control of Giant Foxtail (Setaria faberi) in Soybeans (Glycine max)
Authors: Harrison S. Kent , Williams C. Steven , Wax Loyd M.
Published: May 2019

Interference studies utilizing manipulated and natural infestations of giant foxtail (Setaria faberiHerrm. ♯ SETFA) in soybeans [Glycine max(L.) Merr. ‘Williams’] were conducted at Urbana, IL, in 1982 and 1983. Giant foxtail clumps, each consisting of 3 to 6 plants per dm2, were used to determine the effect of clump density on giant foxtail dry weight and soybean seed yield. In both years, regression equations predicted a soybean seed yield loss of 0.8% for each giant foxtail clump per 9 m of row. The highest density of 30 clumps per 9 m of row reduced soybean yield 26%. In a second study, fluazifop {(±)-2-[4-[(5-(trifluoromethyl)-2-pyridinyl)oxy]phenoxy]propanoic acid} at 0.28 kg ai/ha or fluazifop + alachlor [2-chloro-2’,6’-diethyl-N-(methoxymethyl)acetanilide] at 0.28 + 2.24 kg/ha applied 10 or 15 days after emergence gave maximum giant foxtail control with little or no reduction in soybean seed yield. Interference from uncontrolled giant foxtail began to reduce soybean dry-matter accumulation 15 days after emergence under favorable growing conditions in 1982. Under less favorable conditions in 1983, similar effects were not observed until 25 days after emergence.
Biocontrol of Sicklepod (Cassia obtusifolia) in Soybeans (Glycine max) withAlternaria cassiae
Authors: Walker H. Lynn , Boyette C. Douglas
Published: May 2019

In four tests conducted in 2 years,Alternaria cassiaeJurair and Khan effectively controlled sicklepod (Cassia obtusifoliaL. ♯ CASOB) as indicated by stand counts of the weed and by soybean [Glycine max(L.) Merr.] yields. The number of sicklepod seedlings was reduced more than 90% within 14 days after foliar applications ofA. cassiaeconidia were banded (46 cm) at rates of 4.2 and 2.1 kg/ha (9.4 and 4.7 kg/ha broadcast, respectively). One banded application of 0.04 or 0.4 kg/ha (0.09 or 0.9 kg/ha broadcast, respectively) did not satisfactorily control sicklepod. These results indicate that sicklepod control may be enhanced by multiple applications ofA. cassiae.
Inactivation of Metribuzin in Winter Wheat by Activated Carbon
Authors: Rydrych D. J.
Published: May 2019

Preemergence and postemergence application of metribuzin [4-amino-6-tert-butyl-3-(methylthio)-as-triazine-5(4H)-one] at 0.6 and 1.1 kg ai/ha controlled downy brome (Bromus tectorumL. ♯ BROTE) in winter wheat (Triticum aestivumL. ‘McDermid’) but caused considerable injury without the use of activated carbon over the seeded row. Activated carbon applied in 5-cm bands over the seeded row at 84, 167, and 336 kg/ha protected winter wheat at Pendleton on a silt loam soil. On a sandy loam soil, only a 336 kg/ha rate provided protection from metribuzin. Metribuzin toxicity to winter wheat was more difficult to neutralize when applied preemergence. Downy brome control was not reduced by carbon applied over the wheat row. The best treatment in this study was carbon at 336 kg/ha applied preemergence over the row followed by metribuzin at 0.6 or 1.1 kg/ha postemergence. A 10-week delay between preemergence carbon banding and postemergence metribuzin protected winter wheat from chemical injury.
Weed Management in Minimum-Tillage Peanuts (Arachis hypogaea) as Influenced by Cultivar, Row Spacing, and Herbicides
Authors: Colvin Daniel L. , Wehtje Glenn R. , Patterson Mike , Walker Robert H.
Published: May 2019

Field experiments were conducted in 1982 and 1983 on a Dothan sandy loam (Plinthic Paleudult) at Headland, AL, to investigate minimum-tillage production of peanuts (Arachis hypogaeaL.). The experiments included two peanut varieties: a) ‘Pronto’ (an earlier maturing Spanish type), and b) ‘Florunner’ (a later maturing runner type). Two row-spacing patterns were used: a) conventional 91-cm rows, and b) a modified twin 18-cm row pattern. A constant seeding rate (140 kg/ha) was used regardless of row spacing. Six herbicide systems were evaluated within each combination of variety and row spacing. The Florunner variety outyielded the Pronto variety across both years and weed management systems. Modified twin 18-cm rows outyielded conventional 91-cm rows across years and peanut varieties. Two of the six weed management systems were successful: 1) paraquat (1,1’-dimethyl-4,4’-bipyridinium ion) + oryzalin (3,5-dinitro-N4,N4-dipropylsulfanilamide) (preemergence), paraquat (ground cracking), naptalam (N-1-naphthylphthalamic acid) + dinoseb (2-sec-butyl-4,6-dinitrophenol) (postemergence); and 2) paraquat + pendimethalin [N-(1-ethylpropyl-3,4-dimethyl-2,6-dinitrobenzenamine] (preemergence), acetochlor [2-chloro-N(ethoxymethyl)-6’-ethyl-o-acetotoluidide] + dinoseb (ground cracking), and cyanazine {2-[[4-chloro-6-(ethylamino)-s-triazine-2-yl]amino]-2-methylpropionitrile} (early postdirected spray). Both systems provided the best overall control of Texas panicum (Panicum texanumBuckl. ♯ PANTE), Florida beggarweed [Desmodium tortuosum(Sw.) DC. ♯ DEDTO], and sicklepod (Cassia obtusifoliaL. ♯ CASOB) and were acceptable for use in minimum-tillage peanut production.
Effect of Timing of Spring Applications of Herbicides on Quality of Bermudagrass (Cynodon dactylon) Turf
Authors: Johnson B. Jack , Burns Robert E.
Published: May 2019

Oxadiazon [2-tert-butyl-4(2,4-dichloro-5-isopropoxyphenyl)-δ2-1,3,4-oxadiazolin-5-one] applied to dormant bermudagrass [Cynodon dactylon(L.) Pers. ‘Tifway’ ♯ CYNDA] retarded early foliar growth more than other herbicides evaluated. When bensulide [O,O-diisopropyl phosphorodithioateS-ester withN-(2-mercaptoethyl)benzenesulfonamide] treatments were delayed until after bermudagrass initiated spring growth, foliar growth and quality were generally lower than when the treatments were applied to dormant turf. Retardation of early foliar bermudagrass growth by 2,4-D [(2,4-dichlorophenoxy)acetic acid] + mecoprop {2-[(4-chloro-o-tolyl)oxy] propionic acid} + dicamba (3,6-dichloro-o-anisic acid) was generally the same whether applied to dormant or semidormant turf. This combination of herbicides reduced the quality and density of bermudagrass when applied to growing but not to dormant turf. Atrazine [2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine] did not retard bermudagrass growth or affect density whether applied to dormant or semidormant turf, but turf quality was slightly lower when atrazine was applied to semidormant turf.
Effects of Herbicides on Bermudagrass (Cynodonspp.) Sprig Establishment
Authors: Bingham S. Wayne , Hall John R.
Published: May 2019

Bermudagrass [Cynodon dactylon(L.) Pers. ♯ CYNDA ‘Vamont’, ‘Midiron’, andCynodon dactylonXCynodon transvaalensisBurlt-Davy ♯ CYNTR ‘Tifway’] cultivars were tolerant to oxadiazon [2-tert-butyl-4(2,4-dichloro-5-isopropoxyphenyl)-Δ2-1, 3,4-oxadiazolin-5-one] applied at rates up to 4.5 kg ai/ha during sprig establishment. The rate of shoot growth from sprigs after oxadiazon treatment was excellent and provided adequate ground cover within 3 months. Oxadiazon applications adversely affected root development of the Midiron cultivar as measured by the force required to uproot the sod. Root development of Vamont and Tifway after oxadiazon application was equal to that of untreated bermudagrass. Oxadiazon plus bensulide [O,O-diisopropyl phosphorodithioateS-ester withN-(2-mercaptoethyl)benzenesulfonamide] was inhibitory to both root and shoot growth of all cultivars. Metribuzin [4-amino-6-tert-butyl-3-(methylthio)-as-triazin-5(4H)-one] applications at 3 and 5 weeks after sprigging caused severe root injury to Vamont and Midiron bermudagrass.
Interference of Certain Broadleaf Weed Species in Soybeans (Glycine max)
Authors: Shurtleff Janet L. , Coble Harold D.
Published: May 2019

Field experiments were conducted in 1979, 1980, and 1981 to determine the level of interference five broadleaf weed species exert on soybean [Glycine max(L.) Merr.]. Weed species studied were common cocklebur (Xanthium pensylvanicumWallr. ♯ XANST), common ragweed (Ambrosia artemesiifoliaL. ♯ AMBEL), common lambsquarters (Chenopodium albumL. ♯ CHEAL), sicklepod (Cassia obtusifoliaL. ♯ CASOB), and redroot pigweed (Amaranthus retroflexusL. ♯ AMARE). The following soybean seed yield reductions were observed with a density of 16 weeds/10-m row: redroot pigweed 22%, common lambsquarters 15%, common ragweed 12%, and sicklepod 5%, respectively. At a density of 8 weeds/10-m row, common cocklebur reduced soybean yield 11%. No single weed growth parameter predicted soybean seed yield reduction for all weed species. Soybean height was reduced by sicklepod competition; was not affected by competition from common lambsquarters, common ragweed, or common cocklebur; and was increased in the presence of redroot pigweed at 12 weeks after planting, when measured 30 cm from the weeds. Leaf area of soybean was higher at greater distances from the weed for all weed species. The range of soybean leaf area reductions occasioned by proximity to individual weed species corresponded fairly well with differences in soybean yield reduction.
The Interaction of Soybean (Glycine max) and Five Weed Species in the Greenhouse
Authors: Shurtleff Janet L. , Coble Harold D.
Published: May 2019

The influence of relative planting date on the growth of common cocklebur (Xanthium pensylvanicumWallr. ♯ XANST), common ragweed (Ambrosia artemesiifoliaL. ♯ AMBEL), sicklepod (Cassia obtusifoliaL. ♯ CASOB), and redroot pigweed (Amaranthus retroflexusL. ♯ AMARE) grown in competition with soybean [Glycine max(L.) Merr. ‘Bragg’] was studied in the greenhouse. Increases in dry matter and height were slower for the five weed species than for soybean throughout the period of the study. The root: shoot ratio of soybean was the highest of any plant in the study, while common ragweed, common cocklebur, common lambsquarters, and sicklepod were intermediate, and redroot pigweed was the lowest. Soybean dry weight was always reduced when grown in competition with a weed. Soybean dry-matter production was reduced most when weeds were planted 2 weeks before soybean, especially with common cocklebur and common lambsquarters. Weed dry-matter content was severely reduced when the weed seed were planted simultaneously with or following soybean. Soybean height was usually reduced by competition with the weeds. The height of common ragweed was increased, however, when planted simultaneously with soybean. Common lambsquarters, redroot pigweed, and common ragweed heights were increased when planted 2 weeks prior to soybean.
Response of Three Annual Grasses to Fluazifop
Authors: Derr Jeffrey F. , Monaco Thomas J. , Sheets Thomas J.
Published: May 2019

In greenhouse studies, the butyl ester of fluazifop {(±)-2-[4-[[5-(trifluoromethyl)-2-pyridinyl]oxy]phenoxy]propanoic acid} applied preemergence at 0.035 kg ai/ha gave 91% control of goosegrass (Eleusine indicaGaertn. ♯ ELEIN), 79% control of large crabgrass [Digitaria sanguinalis(L.) Scop. ♯ DIGSA], and 73% control of giant foxtail (Setaria faberiHerrm. ♯ SETFA). In field studies, the butyl ester of fluazifop at 0.56 kg ai/ha applied preemergence gave 79% control of goosegrass, 76% control of large crabgrass, and 53% control of giant foxtail. The butyl ester of fluazifop at 0.07 kg/ha gave 79 to 85% control of each grass at the pretillering stage in field studies. The same rate applied at the early tillering stage gave 84% control of goosegrass but only 53 and 58% control of large crabgrass and giant foxtail, respectively. Relative species response was similar from spray and leaf-spot applications of the herbicide. The butyl ester of fluazifop at 4 μg/plant when spot-applied to leaves of the three grasses at the tillering stage resulted in 65% control of goosegrass but only 20 and 25% control of large crabgrass and giant foxtail, respectively.
Comparison of Chlorophyll Fluorescence and Fresh Weight as Herbicide Bioassay Techniques
Authors: Shaw David R. , Peeper Thomas F. , Nofziger D. L.
Published: May 2019

The sensitivities of chlorophyll fluorescence and fresh weight as bioassay techniques for the determination of metribuzin [4-amino-6-tert-butyl-3-(methylthio)-as-triazin-5 (4H)-one], diuron [3-(3,4-dichlorophenyl)-1,1-dimethylurea], and atrazine [2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine] concentrations in soil were compared. The ratio of the initial inflection point (I) to the variable fluorescence maximum (P) of intact oat (Avena sativaL. ‘Chilocco’) leaves was determined for plants seeded directly into herbicide-treated soil and for those transplanted into treated soil after 14 days of growth in nutrient solution. Using the chlorophyll fluorescence of transplanted oats bioassay, 0-, 0.13-, 0.25-, and 0.50-ppm concentrations could be distinguished from one another within 8 h for metribuzin, within 24 h for diuron, and within 48 h for atrazine. These distinctions between rates could not be made 17 days after seeding into treated soil when using fresh weight as the bioassay indicator. Chlorophyll fluorescence of oats seeded directly into treated soil was also a reliable technique, but required much more time to attain sufficient plant size for convenient chlorophyll fluorescence determinations.
Weed Survey System used in Saskatchewan for Cereal and Oilseed Crops
Authors: Thomas A. Gordon
Published: May 2019

A weed survey system methodology was developed and used annually for 4 yr in the province of Saskatchewan. Based on a stratified random sampling procedure, fields were selected in wheat (Triticum aestivumL.), barley (Hordeum vulgareL.), oat (Avena sativaL.), rye (Secale cerealeL.), rape (Brassica napusL.,Brassica campestrisL.), and flax (Linum usitatissimumL.) crops. The boundaries of the 43 agricultural extension districts in the province formed the strata. The provincial agricultural extension service provided staff to conduct the survey. Computer processing of the data enabled reports, containing summary tables and distribution maps, to be distributed to extension, research, and industry personnel within 3 months after completion of the field survey. The field surveys were conducted late in the growing season before harvest commenced; hence, the weed populations consisted of species that had been present during the early part of the growing season and may have contributed to yield losses. During the 4 yr of the survey, weeds were counted in 4423 fields. Of the 164 species recorded, 97 species occurred in more than three fields. Only 29 species were encountered frequently in the fields. Green foxtail [Setaria viridis(L.) Beauv. # SETVI), wild buckwheat (Polygonum convolvulusL. # POLCO), and wild oat (Avena fatuaL. # AVEFA) were the top three species based on a ranking system using a measure called relative abundance.
Response of Herbaceous Vegetation in East-Central Texas to Herbicides
Authors: Meyer Robert E. , Bovey Rodney W.
Published: May 2019

Twenty herbicides were applied to a rangeland pasture in the Post Oak Savannah Resource Area of Texas in April 1978 and May 1979. At time of treatment, total vegetation cover was 88 to 100%, with 36% grasses and 52 to 64% broadleaf cover. From May 31 through September, total, grass, and broadleaf covers were 89 to 100, 51 to 65, and 27 to 44%, respectively. One to 2 months after treatment, grass cover generally increased except where certain herbicides, particularly bromacil (5-bromo-3-sec-butyl-6-methyluracil), dalapon (2,2-dichloropropionic acid), glyphosate [N-(phosphonomethyl)glycine], or hexazinone [3-cyclohexyl-6-(dimethylamino)-1-methyl-1,3,5-triazine-2,4 (1H, 3H)-dione] had been applied. By September or October in the year of application only dalapon consistently reduced grass cover. In the year following treatment, grass cover was still reduced on the dalapon-treated plots. Most herbicides reduced broadleaf cover in the year of treatment. Broadleaf cover returned most rapidly to those areas treated with dalapon. During the year following treatment, broadleaf cover remained low on plots treated with picloram (4-amino-3,5,6-trichloropicolinic acid), 2,4,5-T [(2,4,5-trichlorophenoxy)acetic acid], and picloram + 2,4,5-T. For plots treated in 1978, the grass and broadleaf standing-crop weights of untreated plots were 490 and 450 kg/ha, respectively, in October 1978, and 2707 and 1033 kg/ha in October 1979. In 1978, grass weight increased with several herbicide treatments whereas only dalapon increased the broadleaf weight. For plots treated in May 1979 and harvested in September 1979, grass and broadleaf standing-crop weights of untreated plots were 2629 and 607 kg/ha, respectively.
DIFFERENZE TERRITORIALI E TIPI DI VOTO. LE CONSULTAZIONI DEL MAGGIO-GIUGNO 1985
Authors: Cartocci Roberto
Published: May 2019

Introduzione

Il referendum sulla scala mobile del 9–10 giugno 1985 è probabilmente destinato ad essere presto rimosso dalla memoria non solo della classe politica, ma anche dei singoli cittadini. Contingenze temporali e politiche hanno congiurato per smussarne rapidamente il rilievo. Il suo esito è stato interpretato unanimemente come una mera conferma delle elezioni del mese precedente, che peraltro hanno avuto ben maggiori riflessi sui rapporti tra i partiti. Sul piano del merito, la concomitante disdetta dell'accordo con i sindacati da parte della Confindustria ha ridefinito radicalmente i termini stessi delle questioni su cui il referendum era stato indetto.
OPZIONI POLITICHE E VINCOLI MILITARI. IL “ DILEMMA DELLA SICUREZZA ” DEL 1914
Authors: Rusconi Gian Enrico
Published: May 2019

Introduzione

Un governo decide di sviluppare il proprio armamento e di migliorare le proprie strategie militari, senza alcuna intenzione aggressiva, ma per garantirsi maggiore sicurezza. Di riflesso i governi degli altri Stati adottano misure analoghe. Il risultato è l'aumento di insicurezza per tutti — maggiore di quanto non fosse all'inizio dell'operazione. In circostanze di acuta tensione internazionale e in presenza di tecnologie e dispositivi strategici instabili, l'esito finale è un'altissima probabilità di guerra.
LA VOLATILITÀ ELETTORALE
Authors: Bartolini Stefano
Published: May 2019

Introduzione

Nelle scienze sociali sono utilizzati di frequente concetti importanti e ricchi di significato teorico che, però, non si prestano facilmente ad essere operazionalizzati e misurati nemmeno in modo indiretto. Il concetto di volatilità elettorale non appartiene a questo gruppo; anzi, rappresenta un esempio, tipico quanto raro, della situazione inversa. Sin dall'inizio della sua relativamente recente intrusione nel gergo degli studi elettorali, la volatilità elettorale ha trovato facile e non controversa misurazione sia al livello dei singoli partiti che del sistema partitico. Si è in generale etichettata questa misura come « mutamento elettorale netto » o « aggregato » tra una elezione e la successiva.
POLARIZZAZIONE PARTITICA E NON-PROPORZIONALITÀ ELETTORALE IN GRECIA
Authors: Seferiades Seraphim
Published: May 2019

Introduzione

Questo saggio si propone di esaminare l'evoluzione del sistema partitico greco nel dopoguerra. Anche se rappresentano solo un subsistema del sistema politico, i partiti assolvono indubbiamente una cruciale funzione di intermediazione fra società e governo e sono, dunque, estremamente importanti per comprendere il rendimento del sistema nel suo complesso. Cionondimeno, fino ad epoca molto recente essi sono stati quasi del tutto trascurati dalla moderna storiografia greca; e non si rischia di esagerare affermando che a tutt'oggi non esiste alcuna ricerca sul sistema partitico in quanto tale, cioè visto come un insieme integrato di attori le cui interazioni concrete e tipizzate sono in grado di influire su altri ambiti, o altri subsistemi, della polity. Se non proprio ignorati del tutto, i partiti sono stati abitualmente confinati in un ruolo reattivo e in nessun caso considerati capaci di strutturare le tensioni sociali. Da questo punto di vista, la Grecia si può considerare un esempio per antonomasia di ciò che Sartori ha chiamato « riduzionismo sociologico », ed è appunto contro questa tendenza che si rivolge il presente lavoro. D'altro canto, con ciò non intendo naturalmente sostenere che i partiti abbiano il potere di creare dal nulla e introdurre nella società civile conflitti non preesistenti nel suo seno. Ma, certo, la natura della competizione interpartitica come tale è un fattore che influisce sull'andamento di questi conflitti e può contribuire ad acuirli o a smorzarli.
Shell fragments as indicators of bed sediment transport in the Tay Estuary
Authors: Al-Dabbas M. A. M. , McManus J.
Published: May 2019

Synopsis

The sediments of the floor of the Tay Estuary are dominated by assemblages of quartzo-feldspathic sands, although pebbles and silts are locally important. The sands are principally of inorganic materials, but they include shell fragments which account for up to 25% of the material, depending upon locality.

Detailed analyses of the shell components of the 0.3–1.2 mm size fraction (400 particles from each site) in the area between Balmerino and Monifieth Bay reveal the presence of much molluscan debris (identified as mature and immature bivalves and gastropods), with significant proportions of bryozoan, barnacle or echinoderm skeletal fragments according to locality. Ostracoda and foraminifera are less common. The shelly material occurs mostly within zones inhabited by the same living organisms.

The characteristic blue-colouredMytilus edulisshell fragments are also recognised up to 6 km landwards of the westernmost known colonies, along the railway bridge.

Shell matter is dissimilar in shape and surface texture to the clastic grains and large shell fragments are frequently associated with sand sized inorganic sediments, which have been shown in flume experiments to respond in a similar manner to hydraulic controls.

TheMytilusis therefore suitable for use as a natural tracer. It indicates up-estuary net residual motion of sediments in the middle and upper reaches. This pattern confirms evidence from heavy mineral assemblages that North Sea derived sands enter the estuary and migrate westwards to accumulate on the upper estuarine tidal flats.
Variations in marsh surface levels in the upper Tay Estuary
Authors: McManus J. , Alizai S. A. K.
Published: May 2019

Synopsis

In the upper Tay Estuary the marshes bordering the northern intertidal mud-flats are dominated byPhragmites communisin the west, withJuncus gerardibecoming more important eastwards, whereAster tripoliumis also significant. Sedimentation on the surface of the marshes at Kingoodie and Invergowrie has been measured at monthly intervals over a twenty-three month period, using stake implants to provide local marker levels. The marsh surfaces were at their greatest heights in early summer and fell during autumn and winter. Maximum accretion rates were measured in spring on the outer marshes at both sites, where net accretion over the entire period was greatest. The net accretion in thePhragmitesmarsh was 2.5 mm, in theAsterbelt 5 mm, in establishedJuncus9 mm and in newly colonisingJuncus8.7 mm, whereas on the adjacent Kingoodie mud flats there was net stability over the twenty-three-month interval. Accretion was less at Invergowrie (3–5 mm) than at Kingoodie (2.5–9 mm). Monthly analysis of the upper 0.5 cm of the surface sediments showed the Invergowrie marsh sediments to be sandier than those of Kingoodie. Silts and clays deposited on the outer marsh surface in spring migrate landward during the summer and autumn. The apparent annual net accretion varied greatly with the specific month used for comparison, with 13 mm net losses based on November figures and 10 mm gains using January data.
Intertidal habitats and benthic macrofauna of the Forth estuary, Scotland
Authors: McLusky Donald S.
Published: May 2019

Synopsis

The intertidal habitats of the Forth estuary are dominated by fine-grained muds, which experience a salinity range of 0–32%, j over the length of the estuary from Stirling to Queensferry. The current total area of the intertidal zone is 23.3 km2, the majority of which is found in the three central bays of Skinflats, Kinneil and Torry Bay. Over the centuries, agricultural and industrial reclamation has reduced by almost 50% the size of the Forth estuary intertidal habitat. The upper estuary has narrow intertidal shores, inhabited almost exclusively by oligochaete worms, which are very abundant due to organic enrichment of the area. The middle estuary is responsible for the greatest biomass and production of the intertidal benthic macrofauna. The lower estuary has a greater diversity of species than the upper and middle estuary, but has a lower biomass and abundance of macrofauna. It is shown that the production/biomass (P/B) ratio of several species in the Forth estuary is lower than that of the same species in other estuaries. This depression cannot be explained by natural environmental variables, and is suggested as being due to the levels of pollutants throughout the area. Despite this depressed productivity, and the threats from further reclamation, the Forth estuary retains abundant populations of intertidal animals, which are an important food source for birds and fish.
Towards a Model of Regional Vessel Near-miss Collision Risk Assessment for Open Waters based on AIS Data
Authors: Zhang Weibin , Feng Xinyu , Qi Yong , Shu Feng , Zhang Yijin , Wang Yinhai
Published: May 2019

The absence of a regional, open water vessel collision risk assessment system endangers maritime traffic and hampers safety management. Most recent studies have analysed the risk of collision for a pair of vessels and propose micro-level risk models. This study proposes a new method that combines density complexity and a multi-vessel collision risk operator for assessing regional vessel collision risk. This regional model considers spatial and temporal features of vessel trajectory in an open water area and assesses multi-vessel near-miss collision risk through danger probabilities and possible consequences of collision risks via four types of possible relative striking positions. Finally, the clustering method of multi-vessel encountering risk, based on the proposed model, is used to identify high-risk collision areas, which allow reliable and accurate analysis to aid implementation of safety measures.
The Evolution of Individual Property Rights in Massachusetts Agriculture, 17th–19th Centuries
Authors: Field Barry C.
Published: May 2019

Economic studies of changes in property rights institutions have been hampered by the use of ideal types. Conceptually we usually identify a small number of discrete property rights regimes, e.g., “open-access,” “common property” and “private property,” and then try to comprehend our data in terms of these categories. But in the so-called real world ideal types are seldom encountered. Instead we usually see complex mixtures of assorted arrangements, all growing or declining or mixing or separating at different rates and in different directions. Models containing nothing but ideal-type concepts are ill-suited to the analysis of such a reality. In this paper I want to examine a case of institutional change where one institutional regime was transformed into another; not by a discrete jump from one system to another, but through a gradual process of institutional adaptation and transition.
Successful Dairy Farm Management Strategies Identified by Stochastic Dominance Analyses of Farm Records
Authors: Kauffman Jonas B. , Tauer Loren W.
Published: May 2019

First-degree and second-degree stochastic dominance were used to separate a panel of 112 dairy farms with ten annual observations per farm into successful and less successful groups using four different performance measures. Logit regression using 16 independent variables was then used to determine important farm characteristics leading to farm success. High milk production and controlling hired labor and purchased feed expenses were important. The selective adoption of new technologies was also important. Optimal debt-asset ratios varied over the 10-year period.
Integrative emotion regulation: Process and development from a self-determination theory perspective
Authors: Roth Guy , Vansteenkiste Maarten , Ryan Richard M.
Published: May 2019

Grounded in self-determination theory's (SDT; Ryan & Deci, 2017) organismic perspective, we present a process view of integrative emotion regulation. SDT describes three general types of emotion regulation: integrative emotion regulation, which focuses on emotions as carrying information that is brought to awareness; controlled emotion regulation, which is focused on diminishing emotions through avoidance, suppression, or enforced expression or reappraisal; and amotivated emotion regulation, in which emotions are uncontrolled or dysregulated. We review survey and experimental research contrasting these emotion regulation styles, providing evidence for the benefits of integrative emotion regulation for volitional functioning, personal well-being, and high-quality relationships, and for the costs of controlled emotion regulation and dysregulation. The development of emotion regulation styles is discussed, especially the role of autonomy-supportive parenting in fostering more integrative emotion regulation, and the role of controlling parenting in contributing to controlled or dysregulated emotion processing. Overall, integrative emotion regulation represents a beneficial style of processing emotions, which develops most effectively in a nonjudgmental and autonomy-supportive environment, an issue relevant to both development and psychotherapy.
Reconsidering the Moralization of Health: Practices Versus Concepts, and What We Can Learn from Evidence-based Research
Authors: THOMAS S. JOSHUA
Published: May 2019

This article aims to do two things. First, it argues that moralization of health occurs not only at the practical level of individual healthcare choices and health states, but also at the conceptual level of health itself. This is most evident in cases where the concept of health is presumed to possess the property of “overridingness” when compared to competing values and norms, that is, when it is treated as taking precedence over other values and norms it may come into conflict with. Second, the article makes a case for being critically skeptical of specific deployments of the concept of health when it has been moralized in this way. In such cases, what typically results is that some other personal value/norm, or set of values/norms, held by the individual is treated as intrinsically at odds with the concept of health, which is presumed, uncritically, to be superior, often because it is taken to be free-standing and self-justifying. Yet, a growing body of evidence-based research suggests that the role played by dimensions of personal meaningfulness in the quality of individuals’ overall health is quite underappreciated. It is useful to think of these dimensions of personal meaning and significance as representing the individual’s values. Thus, taking these data more seriously ought to lead to a reevaluation of the moralization of health at the conceptual level. In the first place, it is not obvious that if the concept of health runs afoul of other values/norms held by an individual, the latter should automatically yield. In the second place, they suggest that other values/norms held by an individual are not necessarily intrinsically opposed to the concept of health, but in fact may go a good distance in support of it.