bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparative Persistence of Dinitroaniline Type Herbicides on the Soil Surface
Authors: Kennedy J.M. , Talbert R.E.
Published: May 2019

Field and laboratory experiments were conducted over a 3-yr period to evaluate the persistence of several dinitroaniline herbicides. Incorporation of these herbicides was delayed for 1, 3, and 7 days after application. Herbicidal activity was assessed by a sorghum bioassay, and by GLC analysis of soil samples. Herbicides least affected by a 2-day delay in incorporation were oryzalin (3,5-dinitro-N4,N4-dipropylsulfanilamide, nitralin 4-(methylsulfonyl)-2,6-dinitro-N,N-dipropylaniline, butralin 4-(1,1-dimethylethyl)-N-(1-methylpropyl)-2,6-dinitrobenzenamine, dinitramine (N4,N4-diethyl-α,α,α-trifluoro-3,5-dinitrotoluene-2,4-diamine), fluchloralinN-(2-chloroethyl)-2,6-dinitro-N-propyl-4-(trifluoromethyl)aniline, and penoxalinN-(1-ethylpropyl)-3,4-dimethyl-2,6-dinitrobenzenamine. Of the herbicides evaluated, trifluralin (α,α,α-trifluoro-2,6-dinitro-N,N-dipropyl-P-toluidine) and profluralinN-(cyclopropylmethyl)-α,α,α-trifluoro-2,6-dinitro-N-propyl-p-toluidine, were the least persistent after a 1-day incorporation delay. Losses of nitralin, butralin, dinitramine, fluchloralin, penoxalin, trifluralin, profluralin, benefin (N-butyl-N-ethyl-α,α,α-trifluoro-2,6-dinitro-p-toluidine), and isopropalin (2,6-dinitro-N, N-dipropylcumidine) increased dramatically when incorporation was delayed 3 or more days. Persistence on the soil fur-face under field conditions was demonstrated the most by oryzalin. After incorporation, dinitramine was least persistent. The effects of temperature in UV light and dark on loss of dinitroaniline herbicides were demonstrated in the laboratory by applying the herbicide to TLC plates of soil. While herbicide losses did occur in 24 h of UV light, differences in herbicide losses were not significantly different between butralin, penoxalin, profluralin, trifluralin, isopropalin, oryzalin, nitralin, fluchloralin, and benefin. Dinitramine was most affected by the UV light. Butralin, oryzalin, nitralin, isopropalin, and dinitramine were least affected by 45 C in the dark with losses of 2 to 10% in 24 h. Profluralin, benefin, and trifluralin were found most volatile with losses of 35%, 25%, and 18%, in 24 h respectively. With increasing moisture levels, no significant increased losses were detected for butralin, nitralin, oryzalin, penoxalin, and isopropalin at the greater moisture contents. There was a moderate increase in the loss of dinitramine with increased soil moisture. AT 33% initial soil moisture, fluchloralin, benefin, and trifluralin were rapidly lost (75 to 94% in 24 h at 30 C). The trifluoro-methyl group was a common structural component where moisture affected the compound's loss. Application of the intermediate to very volatile dinitroanilines to moist soil surfaces without soil incorporation as soon as possible is not feasible unless higher rates of herbicide are applied.
A Method for Assessing Herbicide Performance in Small Plot Experiments
Authors: Hamill A.S. , Marriage P.B. , Friesen G.
Published: May 2019

A method is described that provides an accurate and useful assessment of herbicide performance in small plot experiments. This method is an extension of previous rating systems and provides an assessment of the control of individual species through an estimation of the percentage that each contributes to the total broadleaf or grass weed cover on the whole plot area. It permits data collection on individual weed species but is less time-consuming than counting individual plants and it takes into account the size and vigor of individual weed plants as well as their relative abundance. Further, the system allows tabulation of data from across the entire plot rather than from small areas within the plot. The data can be readily entered into various computerized retrieval systems.
Uptake and Phytotoxicity of Tebuthiuron
Authors: Steinert W.G. , Stritzke J.F.
Published: May 2019

Differences in the phytotoxicity of tebuthiuron (N-[5-(1,1-dimethylethyl)-1,3,4-thiadiazol-2-yl]-N,N′-dimehtylurea) to nine plant species were observed on the basis of calculated GR50values. Japanese brome (Bromus japonicusThunb.) with a GR50value of 0.016 ppmw was the most susceptible and corn (Zea maysL. ‘Gold Rush’) with a GR50value of 0.436 ppmw the least susceptible. There was some growth suppression with foliar application but primary activity on all species was attributed to root uptake. The most significant translocation of labeled tebuthiuron was to the tops of common ragweed (Ambrosia artemisiifoliaL.) plants treated through the nutrient solution where 24.5% of the total amount recovered was detected after 24 h. Only 7.3% of the total amount recovered was detected in the top of rye (Secale cerealeL. ‘Elbon’) plants with the same treatment. With both species, more than 90% of the radioactivity recovered following foliar treatments was still in the treated leaf after 24 h. Less than 5.5% of the recovered activity for both species was in the tops, less than 3% in the roots, and less than 1.5% was in the nutrient solution.
Generation of Alkylarsines from Soil
Authors: Woolson E.A.
Published: May 2019

Products volatilized from arsenical-treated soil were identified and their rates of formation measured to determine if generation of alkylarsines by soils is part of a natural arsenic cycle.74As-sodium arsenate,14C-MSMA (monosodium methanearsonate), or14C-cacodylic acid (hydroxydimethylarsine oxide), were added at 13.3μMoles (10 ppmw As) to individual flasks containing 100 g of Mattapeake silt loam. Either air or N2was used to sweep gases from the flasks and through trapping solutions. Arsenical content in the solutions was monitored by liquid scintillation and assayed for arsenic by atomic absorption spectroscopy. Volatile arsine gases were produced under all conditions. The organo-arsenicals formed volatile compounds most quickly under aerobic conditions. In 160 days, the trapping solutions contained 18.0%, 12.5%, and 1.0% of the activity from soils treated with cacodylic acid, MSMA, or sodium arsenate respectively, when flushed continuously with air, and 7.8%, 0.8%, and 1.8% when flushed with N2. The volatile gases were identified as dimethyl- and trimethylarsine (DMA and TMA) by ion exchange and gas chromatography, and mass spectroscopy. Methylarsine (MA) was not detected. Most of the extractable arsenic remaining in the soil was present as a trimethyl arsenical compound regardless of the treatment. Since arsenic was transferred to air regardless of arsenical treatment, the transfer of arsenic from soil to air is part of the natural arsenic cycle in soils.
Effects of Herbicides on Diseases of Rice (Oryza sativa)
Authors: Inderawati E. , Heitefuss R.
Published: May 2019

Seven herbicides were tested for their effect on growth of Pyricularia oryzae Cavara, Hypochnus sasakii Shirai, and Xanthomonas oryzae Uyeda & Ishiyama Dowson on agar media and for subsequent influence on disease intensity on rice plants (Oryza sativa L.) in the greenhouse. The herbicides studied were: propanil 3′,4′-dichloro-propionanilide), NTN 5$006 [O-(2-nitro-4-methylphenyl)-O-ethyl-N-isopropyl-phosphor-amidothioate], simetryn [2,4-bis(ethylamino)-6-)methylthio)-s-triazine], terbutryn [2-(tert-butylamino)-4-(ethylamino)-6-(methylthio)-s-triazine], nitrofen (2,4-dichlorophenyl-p-nitrophenyl ether), molinate (S-ethyl hexahydro-1H-azepine-1-carbothioate), and aglypt (4-amino-3-methylthio-6-phenyl-1,2,4-triazine-5-on). The growth of P. oryzae, H. sasakii and X. oryzae on culture media containing 10 μg/ml commercial formulation of propanil was reduced to approximately 50% of the control. The other herbicides tested were less effective. Differences in disease severity produced on rice plants treated with the previously mentioned herbicides were in agreement with the results obtained by the culture method. The effect of simetryn and nitrofen on disease severity was stronger than expected from the small direct action on the pathogen in culture. It is suggested that the influence of these two compounds on the disease intensity is due to their effect on the host plant rather than the pathogen directly. Propanil was effective only if applied immediately or up to 1 day before inoculation, indicating that this herbicide is degraded on or within the rice leaves.
Factors Involved in Alachlor Injury to the Potato (Solanum tuberosum)
Authors: Belote J.N. , Monaco T.J.
Published: May 2019

Results from greenhouse and growth chamber studies indicated that alachlor [2-chloro-2′,6-diethyl-N-(methoxymethyl) acetanilide] injury to ‘Superior’ potatoes (Solanum tuberosumL.) was related to time of herbicide application and temperature. Injury to the ‘Superior’ cultivar was observed when alachlor was applied just before potato emergence. Necrosis of shoots near the soil surface, shoot dieback, stem swelling, leaf crinkle, and plant stunting were characteristic symptoms of alachlor injury. Cool temperatures appeared to intensify the injury. ‘Superior’ potatoes outgrew injury within 41 days after treatment. Herbicide placement studies in the growth chamber suggested that alachlor or its metabolites were absorbed by the shoots of emerging ‘Superior’ potatoes. Under growth chamber conditions the ‘Katahdin’ cultivar was injured by preemergence applications of alachlor when the herbicide was applied just before plant emergence. Injury symptoms were similar to those observed on the ‘Superior’ cultivar. ‘Pungo’ and ‘Norchip’ potatoes were tolerant to preemergence applications of the herbicide regardless of time of application.
Evaluation of Herbicides in No-tillage Production of Burley Tobacco (Nicotiana tabacum)
Authors: Chappell W.E. , Link L.A.
Published: May 2019

Burley tobacco (Nicotiana tabacum L. ‘Kentucky 14′) was grown as a no-tillage crop in 1974 and 1975 by planting tobacco directly into an existing stand of orchardgrass (Dactylis glomerata L.) or rye (Secale cereale L.). Paraquat (1,1′-dimethyl-4,4′bipyridium ion) and glyphosate [N-(phosphonomethyl)glycine] were used to kill existing vegetation. Benefin (N-butyl-N-ethyl-α,α,α-trifluoro-2,6-dinitro-p-toluidine), oryzalin (3,5-dinitro-N4,N4-dipropylsulfaniiamide), metribuzin [4-amino-6-tert-butyl-3-(methylthio)-as-triazin-5(4H)one], and chlorbromuron [3-(4-bromo-3-chlorophenyl), 1-methoxy-1-methylurea] were used to control annual grasses and broadleaf weeds.

Glyphosate was generally more effective than paraquat in killing existing vegetation. There was some injury to the tobacco associated with the glyphosate and paraquat treatments, but this was generally confined to those plants which came into contact with the treated herbage. Metribuzin caused severe damage to the tobacco and was discontinued after the first year. Chlorbromuron caused little injury if kept on the surface but injured the tobacco if incorporated by cultivation as in conventional tillage. Benefin and oryzalin caused little or no injury to the tobacco. All four herbicides gave adequate control of annual grasses and broadleaf weeds.
Temperature Effect on Barban Phytotoxicity
Authors: Miller S. D. , Nalewaja J. D. , Dobrzanski A. , Pudelko J.
Published: May 2019

The phytotoxicity of barban (4-chloro-2-butynylm-chlorocarbanilate) applied 14 days after emergence to wheat(Triticum aestivumL. ‘Waldron’) and wild oat(Avena fatuaL.), at constant, fluctuating or alternating day-night temperatures was determined in controlled environmental chambers. Wheat and wild oat susceptibility to barban increased as post-treatment temperature decreased. Maximum barban selectivity for wild oat in wheat occurred with a constant 18 C or an alternating 18 C day and 10 C night post-treatment temperature. At least three days of 10 C immediately following barban application were necessary to cause wheat injury. However, two days at 29 C immediately after barban application in an otherwise 10 C post-treatment regime reduced wheat injury. Further, a night temperature lower than the day temperature after barban application increased wild oat control but did not correspondingly increase wheat injury compared to the constant temperature treatments.
Response of Range Vegetation to Grid Placement and Aerial Application of Karbutilate
Authors: Scifres C. J. , Mutz J. L. , Meadors C. H.
Published: May 2019

Karbutilate [tert-butylcarbamic acid ester with 3(m-hydroxypheny)-1, 1-dimethylurea], formulated as a ball 1.34 cm in diameter, was applied to brush-infested rangeland with fixed-wing aircraft and in a grid pattern by hand at an average density of four balls/12.4 m2 (1.83-m spacing). Control of woody plants with karbutilate applied by hand in an exact grid pattern was not different from aerial applications at the same rate. Based on evaluations at least 24 months after application, karbutilate at 0.56 or 1.12 kg/ha did not control honey mesquite [Prosopis juliflora (Swartz) DC. var. glandulosa (Torr.) Cockerell] in the subhumid Post Oak Savannah or semiarid Rolling Plains of Texas. At 2.24 kg/ha, canopy reduction of honey mesquite averaged 70% with 20 to 25% of the population killed. Post oak (Quercus stellata Wangenh.), blackjack oak (Quercus marilandica Muenchh.), yaupon (Ilex vomitoria Ait.), or winged elm (Ulmus alata Michx.) in Post Oak Savannah were not killed by 2.24 kg/ha. Karbutilate eliminated all vegetation in a 25 to 45-cm diameter circle, depending on concentration of active ingredient in the ball, the year of treatment regardless of vegetation region. The bare areas were revegetated within 2 yr following application in the Post Oak Savannah. However, bare areas in sodgrasses, primarily tobosa [Hilaria mutica (Buckl.) Benth.] and buffalograss [Buchloe dactyloides (Nutt.) Engelm.], where 1.12 and 2.24 kg/ha were applied averaged 20 to 30 in diameter, respectively, 32 months after application to sandy clay loam in the Rolling Plains.
Effect of Cylocate and Aldicarb Alone and in Combination on Growth of Three Sugarbeet Species(Betaspp.)
Authors: Abivardi Cyrus , Altman Jack
Published: May 2019

Growth of sugarbeet(Beta vulgarisL. ‘Mono Hy A1’ and ‘Mono Hy D2′) and(B. patellarisMoq.) seedlings in cycloate(S-ethylN-ethylthiocyclohexanecarbamate)-amended soil infested with the sugarbeet nematode(Heterodera schachtiiSchmidt) was reduced (P = 0.05) at a concentration of 4 jug cycloate/g soil. Although the combination of cyloate with aldicarb [2-methyl-2-(methylthio) propionaldehyde-O-(methylcarbomyl) oxime] resulted in a significantly (P = 0.05) reduced growth of both sugarbeet cultivars andB. patellaris, it did not affect the nematicidal properties of aldicarb. Cycloate alone or in combination with aldicarb did not affect the growth ofB. procumbensChr. Sm. seedlings.
Quackgrass(Agropyron repens)Control in Established Alfalfa(Medicago sativa)With Pronamide
Authors: Fawcett R. S. , Harvey R. G. , Schlough D. A. , Block I. R.
Published: May 2019

The degree and longevity of quackgrass [Agropyron repens(L.) Beauv.] control provided by autumn applications of pronamide [3,5-dichloro(N-1,1-dimethyl-2-propynyl)benzamide] was influenced greatly by alfalfa(Medicago sativaL.) stand density, as well as by rate of application and soil type. When applications were made to a field with a sparse alfalfa stand (10 to 20 crowns/m2), quackgrass yields were reduced the year following pronamide application, but quackgrass reinfested the plots the second year after treatment. Quackgrass yields one and two seasons following autumn treatment with 2.2 kg/ha pronamide were 1480 and 3890 kg/ha compared to 4480 and 4870 kg/ha for control plots. Annual applications of pronamide were necessary to maintain quackgrass control in the sparse alfalfa stand. Pronamide application to a vigorous, dense alfalfa stand (40 to 50 crowns/m2) provided quackgrass control which persisted into the second year after treatment. Quackgrass control ratings one and two seasons after application of 1.1 kg/ha pronamide were 100 and 90%. Pronamide treatments reduced first cutting quackgrass yields, and increased first cutting alfalfa yields. Treatment of the sparse alfalfa stand with 2.2 kg/ha pronamide resulted in first cutting alfalfa and quackgrass yields of 2420 and 990 kg/ha compared to 1430 and 3940 kg/ha for controls. Treatment of a dense alfalfa stand with 1.1 kg/ha pronamide resulted in first cutting alfalfa and quackgrass yields of 3850 and 300 kg/ha compared to 1710 and 1660 kg/ha for controls. Total herbage yields from all cuttings were either slightly decreased when fields with sparse alfalfa stands were treated or remained constant or slightly increased when more dense alfalfa stands were treated. Pronamide applied with potash as the carrier was as effective as when applied in water. Pronamide treatment resulted in increased crude protein concentration in first cutting herbage at all locations in all years. Crude protein concentration in first cutting control herbage ranged from 13.3 to 16.1%. Crude protein concentration in first cutting herbage from plots treated with 1.1 kg/ha pronamide ranged from 17.7 to 20.6%, depending on year and location. In vitro digestible dry matter (IVDDM) concentrations were increased by most rates of pronamide in first, second, and third cutting herbage. IVDDM for first cutting control herbage was 51.4% compared to 61.3% for herbage treated with 2.2 kg/ha pronamide. Acid detergent fiber concentration in first cutting herbage was not affected by pronamide.
Selecting Appropriate Weed Control Systems for Developing Countries
Authors: Young Douglas , Miller Stanley , Fisher Herbert , Shenk Myron
Published: May 2019

Herbicides can increase agricultural productivity and rural welfare where agronomic considerations or labor shortages favor their utilization, but ecological, social, and economic conditions in developing countries often favor alternative weed control methods. Traditional hoeing by peasant farmers in a Northeast Brazil upland region was found to be both effective and economical in comparison with other methods. In another Northeast Brazil region, government herbicide subsidies and payroll taxes were projected to encourage excessive use of herbicides at the expense of displaced workers with few alternative employment opportunities.
Glyphosate and Paraquat Effects on Weed Seed Germination and Seedling Emergence
Authors: Egley G. H. , Williams R. D.
Published: May 2019

Glyphosate [N-(phosphonomethyl)glycine] (30, 125, 250 mg/L) in petri dishes had no effect on germination of prickly sida(Sida spinosaL.), velvetleaf(Abutilon theophrastiMedic), barnyardgrass [Echinocloa crus-galli(L.) Beauv.] and johnsongrass [Sorghum halepense(L.) Pers.] seeds, but additional experimentation indicated that glyphosate stimulated germination of redroot pigweed(Amaranthus retroflexusL.) seeds. Paraquat (1,1′-dimethyl-4,4′-bipyridinium ion) (30, 125, 250 mg/L) did not affect germination of the three broadleaf species, but inhibited johnsongrass and barnyardgrass germination. In the greenhouse, soil surface applications of glyphosate (1.1, 2.2, 9.0 kg/ha) did not significantly affect emergence of these five weed species when they were on or beneath the soil surface at time of treatment. Paraquat (same rates) did not affect broadleaf weed emergence but some rates inhibited grass weed emergence when the seeds were treated while on the soil surface. It is unlikely that normal field use rates of glyphosate will influence weed emergence; whereas paraquat may inhibit the emergence of some grass weeds if the herbicide contacts seeds on the soil surface.
Atrazine Adsorption on Soil as Influenced by Temperature, Moisture Content and Electrolyte Concentration
Authors: Dao T. H. , Lavy T. L.
Published: May 2019

The adsorption of atrazine [2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine] was measured on soil at water:soil ratio of 5:1 and 0.4:1. The adsorption isotherms for atrazine were described by the Freundlich equation. A decrease in water:soil ratio and in soil moisture content led to an increased adsorption of the herbicide. Increasing the concentration of electrolytes in the soil solution by adding solutions up to 0.1M CaCl2increased atrazine adsorption. Greater amounts of atrazine were adsorbed at 30 than at 5 C on four soils at 0.1 bar moisture content. This indicates an endothermic reaction which was observed both before and after correction for differential atrazine solubility due to temperature. Thermodynamic quantities associated with the adsorption reaction were calculated to characterize the adsorption of atrazine on soil.
Arsenic Levels in Crops Irrigated with Water Containing MSMA
Authors: Anderson L. W. J. , Pringle J. C. , Raines R. W.
Published: May 2019

Mature plants of tomato(Lycopersicon esculentumMill. ‘Super Sioux’), cucumber(Cucumis sativasL. ‘Early pickling’), and pinto bean(Phaseolus vulgarisL.), in small field plots, were exposed once to sprinkler or furrow irrigation water containing 0.11 kg/ha or 1.12 kg/ha MSMA (monosodium methanearsonate). Concentrations of MSMA in water were about 0.22 ppmw and 2.2 ppmw for the two rates, respectively. Samples of crops and soil were subsequently analyzed for elemental arsenic content by colorimetric and atomic absorption methods. Arsenic residues were higher, compared to controls, only in crops exposed to MSMA applied in sprinkler irrigation. Average arsenic levels were highest in tomatoes exposed to 2.2 ppmw MSMA by sprinkler irrigation, and after 30 and 45 days were 0.26 ppm and 0.35 ppm, respectively. Average arsenic levels in sprinkler-irrigated crops ranged from double to triple the arsenic levels in control (untreated) crops. Atomic absorption was more sensitive than the colorimetric method and could detect smaller differences in arsenic content of samples. The average arsenic residues in soil varied from 1 to 3 ppm, but the differences could not be attributed to treatment with MSMA.
Dicamba use and Injury on Soybeans(Glycine max)in South Dakota
Authors: Auch D. E. , Arnold W. E.
Published: May 2019

Field experiments were conducted from 1974 to 1977 at Redfield and Centerville, South Dakota, to evaluate the tolerance of soybeans [Glycine max(L.) Merr.] at different growth stages and five varieties of soybeans to dicamba (3,6-dichloro-o-anisic acid) and to determine dicamba residue in the foliage. Yield reduction occurred from applications when soybeans were flowering. Furthermore, germination was reduced by dicamba application at pod-fill. Dicamba residue was detected in foliage 7 days but not 18 days after application. Extent of dicamba use and drift occurrence was determined by a telephone survey of 159 farmers. Thirty-one percent of the farmers surveyed used dicamba in 1976.
Response of Zoysia(Zoysiaspp.) and Bermudagrass(Cynodon dactylon)Cultivars to Herbicide Treatments
Authors: Johnson B. J.
Published: May 2019

Annual herbicide treatments are usually necessary for acceptable control of grassy weeds in turfgrasses and it is important that repeated treatment do not injure the turf. Seven herbicides were applied annually for 4 yr at recommended and three times recommended rates to ‘Emerald’, ‘Meyer’, and ‘Matrella’ zoysia(Zoysiaspp.) and three herbicides were applied annually for 3 yr at similar rates to Tifway′, ‘Tifgreen’, ‘Tifdwarf’ and ‘Ormond’ bermudagrass [Cynodon dactylon(L.) Pers.]. Herbicide treatments delayed early spring green-up of Emerald and Matrella slightly more than Meyer zoysia when compared with respective untreated checks. Four annual treatments of napropamide [2-(α-naphthoxy)-N,N-diethylpropionamide] and profluralin [N-(cyclopropylmethyl)-a,a,a-trifluoro-2, 6-dinitro-N-propyl-p-toluidine] reduced the cover of Meyer more than Emerald or Matrella when final ratings were made. The 10.1 kg/ha rate of prosulfalin {N-[[4-(dipropylamino)-3,5-dinitrophenyl] sulfonyl]-S,S-dimethylsulfilimine} and benefin(N-butyl-N-ethyl-α,α,α-trifluoro-2,6-dinitro-p-toluidine) also reduced the cover of Meyer. Profluralin at 10.1 kg/ha was the only treatment that reduced the stand of Matrella and none of the treatments reduced the stand of Emerald. The 10.1 kg/ha treatments of profluralin and prosulfalin reduced the stand of Tifgreen, Tifdwarf, and Ormond more than Tifway bermudagrass. None of the herbicide treatments reduced the stand of Tifway.
Effect of Stage of Growth on Metribuzin Tolerance
Authors: da Silva J.F. , Warren G.F.
Published: May 2019

Six species of Solanaceae including tomato (Lycopersicon esculentumMill ‘Campbell 28′) were sprayed in the greenhouse at weekly intervals for 4 weeks starting when tomato plants had one true leaf. All species gained tolerance to metribuzin [4-amino-6-tert-butyl-3-(methylthio)-as-triazine-5(4H)one] with age but tomato and black nightshade (Solarium nigrumL.) were the most tolerant and gained tolerance fastest with age. Jimsonweed (Datura stramoniumL.) and eggplant (Solanum melongenaL. ‘Black Beauty’) were the most susceptible species and the ones that gained least tolerance with age. Potato (Solanum tuberosumL.) from true seeds and pepper (Capsicum annuumL. ‘Yolo wonder’) were intermediate in tolerance. In the field, tomato and nine weed species planted in separate plots and kept free from competition were sprayed at weekly intervals starting when tomato plants had one true leaf. Tomato, large crabgrass (Digitaria sanguinales(L.) Scop.), ivyleaf morningglory (Ipomoea hederaceae(L.) Jacq.) and yellow foxtail (Setaria glauca(L.) Beauv.) were the most resistant species to metribuzin and the ones that gained tolerance fastest with age. The most susceptible weeds were velvetleaf (Abutilon theophrastiMedic), common purslane (Portulaca oleraceaL.), pale smartweed (Polygonum lapathifoliumL.), redroot pigweed (Amaranthus retroflexusL.), common lambsquarters (Chenopodium albumL.), and jimsonweed. Low amounts of sunlight during the 3 days before spraying greatly reduced the resistance of tomato to metribuzin.
Control of Green Sagewort in the Nebraska Sandhills
Authors: Morrow L. A. , McCarty M. K.
Published: May 2019

Plots were established in 1970 in the Nebraska Sandhills for the control of green sagewort (Artemisia campestris L.). Herbicides were applied in 1970; 1970 and 1971; 1970, 1971, and 1972; and 1970 and 1972. Nitrogen fertilizer at 45 kg/ha was applied in 1973. Herbicide treatments included 2,4-D amine [(2,4-dichlorophenoxy)acetic acid], 2,4-D ester, 2,4,5-T [(2,4-5-trichlorophenoxy)acetic acid], silvex [2-(2,4,5-trichlorophenoxy)propionic acid], and mixtures of picloram (4-amino-3,5,6-trichloropicolinic acid) or dicamba (3,6-dichloro-o-anisic acid) and 2,4-D amine. Herbicides were most effective for the control of broadleaf weeds when they were applied in 3 consecutive years or in alternate years. Herbicides applied only once did not effectively control broadleaf weeds. When nitrogen was applied after weed control treatments, weed production increased if herbicide applications were not effective. If weed control treatments were effective, nitrogen did not affect weed production.
Herbicide-Root Rot Interaction in Navy Bean
Authors: Wyse Donald L. , Meggitt William F. , Penner Donald
Published: May 2019

Navy bean (Phaseolus vulgarisL.) seedlings grown in soil treated with EPTC (S-ethyl dipropylthiocarbamate) were more susceptible to root rot caused byFusarium solani(Mart.) Appel and Wr. f.phaseoli(Burk.) Snyd. and Hans. than were control seedlings. The navy bean line ‘RRR041,’ which is moderately resistant to root rot, did not show reduced growth when grown in soil infested withF. solaniand treated with EPTC. None of the several herbicides tested increasedF. solanichlamydospore virulence when grown on potato dextrose agar supplemented with herbicides. No herbicide tested increasedF. solanihyphal development in liquid culture or soil. Dinoseb (2-sec-butyl-4,6-dinitrophenol) reduced hyphal development by the greatest amount. Scanning electron micrographs indicated that navy bean plants grown in EPTC had altered hypocotyl surfaces. EPTC and dinoseb increased the exudation of electrolytes, amino acids, and sugars from root and hypocotyl tissue.
Hexaflurate in Soils and Plants
Authors: Allen T. J. , Dodd J. D. , Prince D. K.
Published: May 2019

A clean-up procedure for soil and plant samples utilizing a non-ionic exchange resin column followed by treatment with lead acetate was developed for determining microgram quantities of hexaflurate (potassium hexafluoroarsenate) spectrophotometrically. The method is sensitive to 0.45 ppm with a standard deviation of 0.09 ppm with a recovery of better than 85%. Samples high in organic matter require this treatment to remove interfering substances. Soil samples containing little or no organic matter could be analyzed by using either the lead acetate treatment or the non-ionic exchange resin column. Soil and plant samples analyzed 5 to 7 yr following treatment of south Texas soils for pricklypear (Opuntia spp.) control were found to contain trace quantities of hexaflurate. Downward movement of hexaflurate is either very slow or plants continually assimilate the ion and redeposit it on the soil surface through decomposition of plant parts. The tri- and pent-oxide forms of arsenic did not interfere with analysis of the hexaflurate ion using the clean-up procedure.
Factors Affecting Thiocarbamate Injury to Corn II. Soil Incorporation, Seed Placement, Cultivar, Leaching, and Breakdown
Authors: Burt G. W.
Published: May 2019

The influence of several factors on the injury to corn (Zea maysL.) seedlings from high rates of EPTC (S-ethyl dipropylthiocarbamate) + R-25788 (N,N-diallyl-2,2-dichloroacetamide) was determined in growth chambers. This herbicide combination severely injured 6% of the corn seedlings at rates as low as 14 ppm if the herbicide was poorly incorporated into the soil. If thoroughly incorporated, severe injury did not occur unless the rate of application exceeded 56 ppm. Decreased injury resulted when seed were placed so as to insure rapid shoot emergence. Seed planted at 2 cm with its coleoptile pointed upward or horizontally (with posterior facing upward) was injured less than in other positions, Corn cultivars differ in their susceptibility to EPTC + R-25788 at 30 but not at 20 C. Of the several corn cultivars tested at 30 C, SX-98 was the least injured by EPTC + R-25788. Corn injury was progressively reduced as leaching volumes were increased and as the time from herbicide application to corn planting was increased.
Herbicide Distribution in a Block of Soil
Authors: Robinson E. L.
Published: May 2019

A technique of collecting contiguous soil samples was developed that showed the distribution of nitralin [4-(methylsulfonyl)-2,6-dinitro-N,N-dipropylaniline] in the soil profile. About 60 days after the herbicide was applied and incorporated with a disk harrow, the soil was sampled from two sites in 1968, five sites in 1969, and five sites in 1970. Bioassays, that utilized root lengths of grain sorghum [Sorghum bicolor(L.) Moench ‘Dekalb 57E’], indicated large variation in herbicide concentrations among adjacent or on contiguous soil samples.
Renovation of Turfgrasses with Herbicides
Authors: Johnson B. J.
Published: May 2019

Renovation of common bermudagrass [Cynodon dactylon(L.) Pers.] turf to either ‘Tifway’ or ‘Tifdwarf’ bermudagrasses, zoysia (Zoysia japonica Steud.xZoysia tenuifoliaWilld. ex Trin. ‘Emerald’) or centipedegrass [Eremochloa ophiuroides(Munro) Hack.] was undertaken with the aid of herbicides. Glyphosate [N-(phosphonomethyl)glycine] applied to common bermudagrass turf followed by treatments of MSMA (Monosodium methanearsonate) + 2,4-D[2,4-dichlorophenoxy)acetic acid] alone or in sequence with DCPA (dimethyl tetrachloroterephthalate) reduced the cover of common bermudagrass in renovated Tifway or Tifdwarf bermudagrass turf. Dalapon (2,2-dichloropropionic acid) applied alone or in sequence with DCPA, MSMA + 2,4-D, or DCPA + MSMA + 2,4-D also reduced coyer of common bermudagrass in some plantings. Paraquat (1,1′-dimethyl-4,4′-bipyridinium ion) and cacodylic acid (hydroxydimethylarsine oxide) did not reduce the cover of common bermudagrass in turf renovations. Slower growing Emerald zoysia and centipedegrass could not compete with the common bermudagrass that escaped the herbicide applications and renovation was unsuccessful.
Adsorption and Mobility of Metribuzin in Soil
Authors: Savage K. E.
Published: May 2019

The sorption equilibria and relative mobility of metribuzin [4-amino-6-tert-butyl-3-(methylthio)-as-triazin-5(4H)-one] were evaluated on 16 soils from the lower alluvial flood plain of the Mississippi River as a function of soil properties. Metribuzin sorption and mobility were significantly correlated with each other and both parameters were significantly associated with clay content, organic matter, and water content at 0, 0.33 field capacity (FC), and 15 bars tension. Prediction equations for adsorption (K1= −1.10 + 0.08 FC) and mobility (Rf= 0.81 − 0.015 FC) indices were developed based on water content at 0.33 bar tension (FC). A competitive effect was observed between the combination of various levels of clay and organic matter as related to metribuzin adsorption.
MILITARI E POLITICA: UNA RASSEGNA DI STUDI
Authors: Pasquino Gianfranco
Published: May 2019

Introduzione

La letteratura sul ruolo dei militari in politica è cresciuta negli ultimi anni in maniera considerevole, seguendo di pari passo la crescente importanza del fenomeno militare sotto i più diversi aspetti. Basti pensare che «il 12% degli Stati indipendenti nel 1961 era guidato da governi i cui leaders avevano preso il potere con colpi di Stato. Nel 1966 la percentuale era salita a 19, nel 1972 a 27». Alla crescita quantitativa delle analisi sul ruolo politico dei militari non ha però fatto riscontro un'adeguato approfondimento teorico, cosicché oggi il campo dello studio dei militari è caratterizzato da una varietà di definizioni, di prospettive, di generalizzazioni e di ipotesi che rasenta spesso la confusione. Si sente fortissima l'esigenza di una teoria storico-comparata che possa portare ordine e immaginazione.
LA CULTURA POLITICA: STORIA INTELLETTUALE DEL CONCETTO
Authors: Almond Gabriel A.
Published: May 2019

Introduzione

Una nozione di cultura politica, o almeno qualcosa del genere, esiste sin da quando si è parlato o scritto di politica. Nei pensatori classici, come Platone o Aristotele, si trovano esplicitate anche le sottocategorie che usiamo oggi nell'analisi della cultura politica. Ad esempio, subcultura politica dell'élite, socializzazione politica, mutamento culturale. Fatte le debite differenze, né il maggior teorico del Rinascimento, Machiavelli, o dell'Illuminismo, Montesquieu, raggiungono la stessa profondità di Aristotele quando parlano delle proprietà culturali di nazioni e gruppi. Solo Tocqueville nei suoi studi sugli atteggiamenti delle classi sociali durante la Rivoluzione Francese e sugli orientamenti della cultura americana raggiunge un livello di raffinatezza comparabile.
DESTRA, SINISTRA O CENTRO? SULLA LEGITTIMAZIONE DI PARTITI E COALIZIONI NEL SUD EUROPA
Authors: Di Palma Giuseppe
Published: May 2019

Introduzione

In ultima analisi i partiti politici servono a governare, ma quali partiti hanno titolo a governare? Se in molti paesi la scelta riflette pacificamente i normali mutamenti nelle preferenze partitiche degli elettori, le cose non sono cosí semplici nell'Europa del Sud. Il risorgere di un sistema di partiti dopo decenni di autoritarismo in Spagna e Portogallo, la ripresa della competizione partitica dopo un piú breve intervallo di dittatura militare in Grecia, una crisi acutissima dei vecchi equilibri di partito e di coalizione in Italia, aprono infatti un periodo di difficile transizione e propongono con urgenza il delicato dilemma continuismo-rottura, mettendo cosí in questione la credibilità di governo e persino la legittimità di molti partiti, nonché dei sistemi di partito e perciò stesso delle coalizioni di governo che essi esprimono. A riguardo di queste ultime possiamo offrire due criteri di classificazione su cui si appuntano scelte e valutazioni di merito: il primo e sincronico ha come oggetto la composizione, l'ambito e la collaborazione spaziale lungo lo spettro partitico di una data coalizione di governo; il secondo e diacronico ha come oggetto l'alternanza o meno delle coalizioni. A metterli insieme, i due criteri ci danno quattro modi di stare al governo (Fig. 1), compresi tra due estremi idealtipici — governare insieme e a tempo indefinito, governare separatamente e a turno.
LO STATO IN AMERICA LATINA
Authors: Dillon Soares Glaucio Ary
Published: May 2019

Introduzione

Il punto di partenza di questo articolo è la convinzione che non è possibile elaborare una teoria generale dello Stato valida per tutti i tempi e per tutti i paesi, ma che è necessario, invece, cercare di individuare le variabili piú significative delle diverse esperienze storiche e costruire su questa base tipologie dinamiche e comparate che consentano di porre altre domande feconde sul ruolo dello Stato con particolare riferimento al suo intervento nell'economia. Il presente articolo intende fornire un contributo in questo senso sulla base specifica dell'esperienza latinoamericana.
AREE ELETTORALI E FORZA DEI PARTITI: 1968–1976
Authors: Sadocchi Sandro
Published: May 2019

Introduzione

Dopo ogni consultazione elettorale esiste, da parte dei partiti politici e dell'opinione pubblica, la tendenza ad associare tra loro le entità territoriali dove i partiti hanno riportato risultati simili, al fine di visualizzare le zone di influenza di un certo partito o di una coalizione di partiti. L'interesse per questo argomento ha alimentato la letteratura politologica con un certo numero di lavori riguardanti la geografia elettorale.
UN MANUALE DI SCIENZA POLITICA
Authors: Morlino Leonardo
Published: May 2019

Introduzione

Manuale o handbook è una parola che suscita nelle scienze sociali molte speranze, illusioni e, spesso, notevoli delusioni. L'esigenza di disporre di manuali nasce dalla necessità di far riferimento a un sicuro, consolidato e coerente insieme di conoscenze da parte dei cultori di una materia. Scrivere un manuale significa, dunque, raccogliere, sistemare, rendere coerenti e, finalmente, presentare l'intero corpo teorico elaborato dalla disciplina. Un manuale è costitutivamente — per le stesse necessità e fini a cui risponde — molto poco problematico. Dal momento che deve sistemare e presentare quanto è ormai acquisito, dovrà dare molto piò spazio al relativamente certo, piuttosto che all' « incerto ». D'altra parte, in termini di prospettive analitiche emergeranno le direzioni di ricerca che in quel particolare momento sembrano piú proficue.
RICAMBIO ELETTORALE E IDENTIFICAZIONI PARTITICHE: VERSO UNA EGEMONIA DELLE SINISTRE?
Authors: Sani Giacomo
Published: May 2019

Introduzione

I risultati delle elezioni amministrative del 15 giugno hanno fatto da sfondo ai dibattiti politici di questi ultimi mesi ed hanno condizionato i comportamenti e le tattiche dei protagonisti della vita politica. Difficoltà, sbandamenti, tentativi di «rifondazione» nella DC, dibattito all'interno del PSI sulla strategia del partito nel futuro, rinnovate aperture e prese di posizione del PCI, incertezza e posizione di attesa negli altri partiti, tutto ciò riflette in larga misura i mutamenti intervenuti nella forza dei partiti a seguito delle elezioni per il rinnovo dei consigli comunali, provinciali e regionali che hanno interessato la quasi totalità dell'elettorato (vedi Tabella 1). Il successo riportato dalle sinistre il 15 giugno è stato generalmente interpretato da politici ed osservatori come una svolta molto significativa non solo agli effetti della formazione degli organi di governo a livello locale, ma anche agli effetti del quadro politico piú generale, cioè degli schieramenti e degli assetti del sistema partitico in sede nazionale negli anni futuri. Ai dirigenti politici, insomma, i mutamenti nei rapporti di forza intervenuti il 15 giugno hanno posto con urgenza il problema di riesaminare, adeguare o eventualmente re-inventare strategie adatte alla nuova situazione.
Narrow Band Photometry of Comet Kohoutek
Authors: Brown Larry W.
Published: May 2019

Photometric observations of emission line features of the coma of comet Kohoutek (1973f) were made with narrow band interference filters. The emission features observed were CN(3879 A°), C3(4057 A°), and C2(4732, 5165,5634 A°). The radial dependence of the emission was investigated by employing six diaphragms set concentrically about the brightest part of the comet's head.

The photometric observations were made at the Optical Research Facility and Observatory of NASA/Goddard Space Flight Center (GSFC) in Greenbelt, Maryland. The observatory is located 13 miles Northeast of Washington, D.C. (longitude = 5h07m18s22, latitude = +39° 01′ 11.″48, altitude = 49 meters) and is operated by the Laboratory for Optical Astronomy of Goddard (GSFC).
H20+ Ions in Comets: Comet Kohoutek (1973f) and Comet Bradfield (1974b)
Authors: Wehinger Peter , Wyckoff Susan
Published: May 2019

Herzberg and Douglas (1973) first predicted that the H20+ ion might be observable in comet tail spectra. Subsequently Lew and Heiber (1973) discovered the laboratory spectrum of H20+. In October and November 1973, Herbig (1973), Benvenuti and Wurm (1974), and Wehinger and Wyckoff (1974) reported unidentified features in the tail spectrum of comet Kohoutek. On the basis of these observations, Herzberg and Lew (1974) made a tentative identification by pointing out coincidences with several strong low-lying lines in the H20+ spectrum. Further observations were obtained in November 1973 and January 1974 at the Wise Observatory and by Herbig at the Lick Observatory. Six vibronic bands (5-0 through 10-0), including a total of approximately 50 rotational lines were identified with laboratory H20+ spectrum (Wehinger et al. 1974). The predicted spin splitting of those lines with 2 to 4 Å separation was observed in the coude spectra of Herbig.
Radio Detections of Cometary Molecular Transitions: A Review
Authors: Snyder L E.
Published: May 2019

The various radio searches for cometary molecules finally came to fruition with the radio detections of CH, OH, HCN and CH3CN and several unidentified species in Comet Kohoutek (1973f) and the detection of H2O emission from Comet Bradfield (1974b) As a result of these detections we have learned something about why past radio searches of other comets for molecules were less than successful. Also, it is now possible to identify and discuss some of the similarities and differences between cometary molecules and interstellar molecules, particularly with regard to the excitation and chemistry Finally, given the observed projected densities and resulting gas production rates, the feasibility of future radio molecular observations of comets can be discussed.
A High-Velocity Component of Atomic Hydrogen in Comet Bennett (1970 II)
Authors: Keller H. U. , Thomas Gary E.
Published: May 2019

The Lyman alpha emission from Comet Bennett (1970II) was measured near perihelion (March 1970) by the University of Colorado ultraviolet photometer experiment on OGO-5 The spectrometer field of view of about 3° crossed the cometary hydrogen coma four times. The hydrogen coma was observed to extend more than 30 x 106 km in the antisolar direction.

A model for the hydrogen density was developed which took the actual cometary motion and the gradients of the forces of gravitation and radiation pressure into account Exact trajectories of atoms in the orbital plane representing the column densities perpendicular to the plane were calculated. The variation of the hydrogen lifetime along the trajectory as well as the solar Lα profile were considered.
Photometric Observations of Recent Comets
Authors: Ney E. P
Published: May 2019

The first infrared observations of a comet were made by Becklin and Westphal (1966) who studied Comet Ikeya Seki (1965f) Their data at wavelengths of 1.6 to 10 microns revealed that this comet was a bright infrared object because of thermal radiation by dust grains in the coma. This is just another example of the importance of dust in infrared astronomy. The success of infrared is largely due to the extreme visibility of dust which reveals itself by reradiation in the infrared and by scattering or extinction in the visible. Optical opacities are χ = 104cm2/gm for one micron dust particle, for plasma free electrons, χ = 10-4cm2/gm for neutral molecules. By the time Bennett came along (1969i) infrared techniques were well developed, and the presence of an emission feature at 10 and 20 microns had been discovered in the infrared energy distributions of late type luminous supergiant stars (Woolf and Ney, 1969, for a summary see Ney (1972)).
Focused written corrective feedback and linguistic target mastery: Conceptual replication of Bitchener and Knoch (2010)
Authors: Ekiert Monika , di Gennaro Kristen
Published: May 2019

This study replicates Bitchener and Knoch (2010), which reported that written corrective feedback (WCF) targeting two single-rule English article functions (first mention a and subsequent mention the) is effective. The current replication study repeats the original study in most respects but adds to the assessment of the intervention's efficacy by recording the impact of focused WCF on all functional article uses, and not just on the two uses targeted by the WCF. The results of the replication study partially confirm Bitchener & Knoch's results and introduce some further differentiated findings. It is concluded that while the focused WCF leads to increased accuracy in the targeted functions of articles, the same WCF may negatively impact the remaining non-targeted article functions, especially for the group that received the most explicit WCF in the form of metalinguistic explanation.
Cost-Effectiveness Analysis of Non-invasive Prenatal Testing for Down Syndrome in China
Authors: Xu Yan , Wei Yan , Ming Jian , Li Na , Xu Ningze , Pong Raymond W. , Chen Yingyao
Published: May 2019

Objectives

There is little evidence in China regarding the cost-effectiveness of non-invasive prenatal testing (NIPT) for Down syndrome (DS). This study aims to evaluate the cost-effectiveness of NIPT and provide evidence to inform decision-making.

Methods

To determine the cost-effectiveness of NIPT for DS, a decision-analytic model was developed using the TreeAge Pro software from a societal perspective in a simulated cohort of 10 000 pregnant women. Main indicators were based on field surveys from sampled hospitals in four locations in China and a literature review.

Results

The conventional maternal serum screening (CMSS) strategy, contingent screening strategy (NIPT delivered to high risk pregnant women after CMSS), and universal screening strategy could prevent 3.02, 7.53, and 9.97 DS births, respectively. NIPT would decrease unnecessary invasive procedures, resulting in fewer procedure-related miscarriages. The cost-effectiveness ratio of the contingent screening strategy was the lowest. When compared with the CMSS strategy, the incremental cost per DS birth averted by the contingent screening strategy and universal screening strategy were USD 20,160 and 352,388, respectively. One-way sensitivity analysis showed that, if the cost of NIPT could be decreased to USD 76.92, the cost-effectiveness ratio of the universal screening strategy would be lower than the CMSS strategy.

Conclusions

Although NIPT has the merits of greater effectiveness and safety, CMSS is unlikely to be replaced by NIPT at this time because of NIPT's higher cost. Contingent screening may be an appropriate strategy to balance the effectiveness and cost factors of the new genetic testing technology.