bluuebunny/crossref_metadata_2025_split huggingface dataset:
Time and Rate of Fertilizer Application for Seeded Warm‐season and Bluegrass Pastures. I. Yield and Botanical Composition1
Authors: Rehm G. W. , Sorensen R. C. , Moline W. J. 
Published: July 2010

AbstractField studies were initiated in 1971 and continued through 1974 to evaluate the influence of time and rate of fertilizer application for both seeded warm‐season and bluegrass (Poa pratensis L.) pastures. The warm‐season pastures consisted of a mixture of big bluestem (Andropogon gerardi Vitman), switchgrass (Panicum virgatum L.), indiangrass (Sorghastrum nutans L.) and sideoats grama (Bouteloua curtipendula L.). Prior studies had shown that fertilization would increase production of several forage species. Yet results were often conflicting and influence of time of fertilizer application had not been investigated. Rates of fertilization ranged from 0 to 180 kg N/ha and from 0 to 34 kg P/ha. Fertilizer was broadcast in both early and late spring on established stands on Crofton silt loam, a Typic Usthorthert. Applications were repeated each year. The relationship between yields of the bluegrass to rate of applied N and P was linear in each year of the study. Higher yields were recorded when fertilizer was applied in early (15 April) compared to late (30 May) spring.For the warm‐season grasses, the relationship of yields to rate of N application was linear in 1971 and 1972 but was curvilinear in 1973 and 1974. Yields were linearly related to rate of P applied in all years except 1972. Botanical composition of the warm‐season grass mixture was influenced by time of fertilization. Early spring application encouraged encroachment by cool‐season species, intermediate wheatgrass (Agropyron intermedium Host.), which dominated the stand after 2 years of fertilization. Application of N rates less than 90 kg/ha in late spring did not result in encroachment. At the lower N rates, higher yields of warm‐season grasses were observed when fertilizer was applied in late spring.
Differential Response of Wheat Cultivars to Al1
Authors: Lafever H. N. , Campbell L. G. , Foy C. D. 
Published: July 2010

AbstractPrevious observations indicate that the adaptability of certain wheat (Triticum aestivum L. em Thell) cultivars to strongly acid conditions is due to their ability to tolerate high levels of free aluminum. Studies were conducted to determine the differential response of cultivars to high levels of exchangeable Al in soil and to correlate these data to nutrient solution screening techniques. Field plots were located on a naturally low pH (4.5) Wooster silt loam soil (fine, loamy, mixed, mesic Typic Fragiudalf) in which pH levels, and, thus, available Al were controlled by liming. Data on yield, height, maturity, and winter survival of 43 wheat cultivars and experimental lines and two barley (Hordeum vulgare L. emend.) cultivars were obtained in 1973, 1974, and 1975. Field results were related to measurements of root length, weight, and number, leaf length and top weight of plants grown for 10 days in nutrient solutions containing 0 and 8 ppm Al. Many cultivars developed in the eastern USA appeared to have been selected unconsciously for Al tolerance. ‘Fultz’, ‘Trumbull’, ‘Fulcaster’, ‘Thorne’, ‘Seneca’, ‘Lucas’, ‘Butler’, ‘Fulton’, ‘Atlas 66’, ‘Blueboy’, and ‘Pennoll’ were classified as tolerant; whereas, most Indiana developed varieties such as ‘Abe’, ‘Arthur’, ‘Arthur 71’, ‘Redcoat’, ‘Reed’, and ‘Riley’ tended to lack aluminum tolerance. ‘Logan’, ‘Fairfield’, ‘Ruler’, and many of the experimental lines exhibited intermediate degrees of tolerance, indicating that this trait was not simply inherited. Root length in nutrient solutions containing Al was a good indicator of varietal response to the high acid conditions of the field. Nutrient solution techniques provide an efficient nondestructive screening method for use in the development of Al‐tolerant wheat cultivars.
Phytotoxicity and Efficacy of Nematicide Seed Treatment on Wheat, Rye, Oats, and Ryegrass1
Authors: Hoveland C. S. , Rodriguez‐Kabana R. , Haaland R. L. 
Published: July 2010

AbstractRoot‐pruning nematodes can restrict roots of winter annual forage grasses (seeded in autumn) and prevent utilization of water at greater than normal depths during autumn droughts in the southeastern U.S. The efficacy of seed treatment as an inexpensive method for precise delivery of the nematicide in the seedling root zone was studied in the greenhouse. Seed of ‘Maton’ rye (Secale cereale L.), ‘Coker 68‐15’ wheat (Triticum aestivum L.), ‘Florida 501’ oats (Avena sativa L.), and ‘Gulf’ ryegrass (Lolium multiflorum Lam.) were treated in acetone solutions of oxamyl (methyl N′, N′‐dimethyl‐N {(methylcarbamoyl) oxy}‐1‐thiooxamiimidate), carbofuran (2, 3‐dihydro‐ 2, 2‐dimethyl‐7‐benzofuranyl methylcarbamate) or phenamiphos (ethyl‐3‐methyl‐4‐(methyl thio) phenyl (1‐ methylethyl) phosphoramidate) containing 0, 0.25, 0.50, 1.25, 2.5, or 5.0% (w/v) nematicide. Seeds were planted in sterilized soil or soil naturally infested with lance (Hoplolaimus galeatus (Cobb) Sher.) and stunt (Tylen‐ chorhynchus claytonii Steiner) nematodes. Both oxamyl and carbofuran were relatively non‐toxic to germinating seed while phenamiphos was quite phytotoxic. Relative tolerances of the grass species to nematicide seed treatment were rye>wheat>ryegrass>oats. Seed treatment at 1.25% w/v with all nematicides reduced the soil population of stunt nematodes, although the effect was greatest on wheat and oats. Stunt nematodes on wheat declined 65% or more with treatment concentrations of 1.25% w/v. Oxamyl was most effective in reducing populations of lance nematodes. These results indicate that seed treatment is a promising economical method of applying nematicide to control plant parasitic nematodes.
Yield and Quality Trends of Tall Fescue Grazed with Different Subdivisions of Pasture1
Authors: Vartha E. W. , Matches A. G. , Thompson G. B. 
Published: July 2010

AbstractSubsequent to a grazing experiment which showed average daily gains of growing cattle on N‐fertilized tall rescue (Festuca arundinacea, Schreb.) to be similar whether grazed continuously or in a two‐paddock grazing round baled hay aftermath system, a study was done to determine short‐term changes in the quantity and quality of herbage‐on‐offer for pastures with 0, 2, or 4 subdivisions of grazing. The objective of this experiment was to provide possible explanations for the lack of differences in rate of gain in the on‐going grazing trial. Six groups of three weaner calves grazed replicated pastures of N‐fertilized tall rescue (0.256 ha/group) for 80 days in spring‐summer and 40 days in fall. Cattle were used as defoliators, and animal performance data are not presented. During each grazing cycle, cattle were continuously grazed on pastures with no subdivisions, rotated every 20 days with 2 subdivisions and every 10 days on pastures with 4‐subdivisions. At 5‐day intervals, herbage samples (10 × 0.26 m2) were cut to ground level from each subdivision under grazing. These samples were later analyzed for in vitro dry matter disappearance (IVDMD), N, and mineral composition. Residual herbage samples were also obtained following the completion of the second and third grazing cycles.In the spring and summer (20 May to 7 August), subdivision treatments did not differ in average amount of herbage‐on‐offer/ha. On removal of cattle on 7 August when the no‐subdivision treatment was fully grazed, amount of residual herbage among treatments was nearly the same. Percent IVDMD declined curvilinearly in all treatments from an average of 64% in May to 49% in mid‐July, followed by a 2.5 percentage unit increase in August.In the fall (17 September to 27 October), average amount of herbage‐on‐offer/ha ranged from 800 to 1,000 kg/ha higher with 4 subdivisions than with the other treatments. Fall digestibilities ranged from 62 to 43% IVDMD. Low values occurred at the end of the grazing cycle, especially in the 4 subdivision treatment where the most residue (trampled herbage) was observed.Composited herbage samples from the no‐ and 4‐subdivision treatments showed little difference between the spring‐summer and fall grazing cycles in range of concentrations for N and eight minerals.The results indicate that subdividing pastures for rotational grazing did not have a marked effect on average quantity and quality of tall rescue during the spring and summer. However, pastures with 4 subdivisions did provide more herbage growth in the fall. These findings may partially explain why cattle daily gains in another on‐going grazing trial have not been different.
Changes in Water Potential During Pressure Bomb Measurement1
Authors: Wenkert W. , Lemon E. R. , Sinclair T. R. 
Published: July 2010

AbstractPotential errors in the pressure bomb measurement of water potential are important to a wide range of users. We report here specifically on changes in water potential within the chamber associated with measurement technique. Individual soybean leaves (Glycine max L..) were measured repetitively while left in the chamber for varying amounts of time, both with and without a plastic covering. Thermocouples were used to monitor leaf and air temperature during compression. For uncovered leaves, initially at −3 to −5 bars, water potential decreased as much as 1 bar during a single measurement due to drying associated with high tissue temperatures during the compression. Passing the entering air through water in the bottom of the chamber did not limit either the temperature increase or desiccation. When the leaves were wrapped in more than one layer of plastic, they were effectively insulated from the temperature increase in the chamber and decreases in water potential were reduced to 0.1 to 0.2 bars per measurement. Changes in water potential with time were negligible when desiccation was prevented. We conclude that the pressure bomb can yield highly reproducible measurements if the leaves are covered to prevent desiccation.
Concentration, Composition, and in vitro Disappearance of Hemicellulose in Tall Fescue and Orchardgrass1
Authors: Daughtry C. S. T. , Holt D. A. , Lechtenberg V. L. 
Published: July 2010

AbstractHemicelluloses are complex groups of cell wall polysaccharides which comprise significant proportions of the dry matter of many forages. Factors affecting hemicellulose concentration in grasses could influence efficient utilization of fibrous feeds by ruminants. The purpose of this research was to evaluate the effects of N‐fertilization, maturity, and plant tissue on the disappearance of cell wall constituents (CWC), hemicellulose, and the components of hemicellulose in two forage grasses during in vitro rumen fermentation.Tall fescue (Festuca arundinacea Schreb.) and orchardgrass (Dactylis glomerata L.) plots on a Chalmers silty clay loam (fine silty typic argiaquolls) were fertilized with either 0 or 112 kg/ha of N as urea. The grasses were labeled with 14CO2 on 21 May 1975 (heading stage) and were sampled on the 1st, 7th, and 19th days after labeling. Cell wall constituents were prepared by neutral detergent extraction of lyophilized, ground tissue before and after the tissue had been incubated in buffered rumen fluid for 48 hours. Hemicellulose was hydrolyzed in situ with 1.0 N H2SO4. Sugar residues of hemicellulose were separated and identified by paper chromatography and the radioactivity was measured by liquid scintillation counting.The concentrations of each cell wall component of tall rescue and orchardgrass generally were not significantly different (P = 0.10). Leaves of N‐fertilized grass contained 51.1% CWC and 29.5% hemicellulose compared to 58.1% CWC and 24.0% hemicellulose in leaves of non‐fertilized grass. Concentrations of CWC and hemicellulose in stems were 10 and 5 percentage units, respectively, higher than in leaves. Xylose and arabinose were the major components of hemicellulose, accounting for 37.8 and 23.6%, respectively, of the hemicellulose. Glucose, galactose, and uronic acids formed the remainder. The relative proportion of xylose in the hemicellulose of leaves declined an average of 14% during the sampling period.Disappearance of CWC and hemicellulose was 52.6 and 69.1%, respectively, during in vitro tureen fermentation. All of the hemicellulose components were not fermented equally. The ratio of xylose:arabinose increased from 1.6 in the original leaf tissue to 3.0 after rumen fermentation. Arabinose in vitro disappearance was 74.7% compared to 53.7% for xylose. 14C‐Xylose accounted for 50% of the radioactivity in hemicellulose before rumen fermentation and more than 70% of the radioactivity in hemicellulose after fermentation. Greater than 96% of 14C‐arabinose and nearly all of the radioactivity in glucose and galactose were lost during fermentation, further indicating that the constituents of hemicellulose are not equally available to rumen microorganisms. An inverse relationship between hemicellulose in vitro disappearance and the xylose: arabinose ratio suggests possible selection criteria for improving forage utilization by ruminants.
Metabolic Changes in Indian Ricegrass Seeds in Relation to Coat‐imposed and Embryonal Dormancy1
Authors: McDonald M. B. , Khan A. A. 
Published: July 2010

AbstractIndian ricegrass, Oryzopsis hymenoides (Roem & Shult.) Ricker, seeds are dormant at harvest and show a coat‐imposed as well as an embryo dormancy. In this investigation we report on the relationship of the two types of dormancy to changes in certain enzymes implicated in seed germination and seedling growth. Scarification with concentrated sulfuric acid followed by hormonal treatments released both types of dormancy. The removal of seed coat was essential for germination and for the induction of peroxidase, α‐amylase, and ribonuclease activities. Marked quantitative differences were found in cathodic isoperoxidases from intact and scarified seeds as early as 24 hours after imbibition suggesting their involvement in pregermination processes. Hormones had little effect on peroxidases. Inhibitor studies indicated that all isoperoxidases with the exception of one might be synthesized de novo. The enhancement of α‐amylase and ribonuclease by gibberellic acid and kinetin in scarified seeds occurred only after 24 hours. This result suggests, that gibberellin or cytokinin modulation of these enzymes might be post‐germination events and that seeds are presumably deficient in these hormones. Qualitative and quantitative changes were not detected in isoribonucleases of intact seeds. The differences in isoribonucleases between hormone treated and untreated scarified seeds appeared only after 24 hours. The enhancement of RNA polymerase activity by chilling in intact seeds at zero time and in scarified seeds at 24 hours may be due to gene derepression directly related to the release of embryonal dormancy.
Alkaloid Levels in Phalaris aquatica L. as Affected by Environment1
Authors: Ball Donald M. , Hoveland Carl S. 
Published: July 2010

AbstractPhalaris aquatica L. (also referred to as P. tuberosa L.), a species widely grown in Australia, may have forage potential in the southeastern U.S. and, therefore, has been made the subject of an Auburn University breeding program. In Australia, however, livestock toxicities have been reported from alkaloids in the forage. Field, greenhouse, and environmental chamber experiments were conducted to determine the effect of N fertilization, radiation density, and drought stress on alkaloid concentration of Phalaris aquatica lines. Nitrogen applications up to 336 kg/ha had no effect on alkaloid concentrations in the field on a Cahaba fine sandy loam (Typic hapldult, fine‐loamy, siliceous, thermic) soil, and 224 kg/ha had only a slight effect in an environmental chamber study. Shading to 30 or 55% of full sun caused slight alkaloid increases in the field, but decreased radiation had no effect in an environmental chamber. The order of alkaloid concentration in aerial portions of individual plants of two genotypes was: upper one‐half of leaves>leaf sheaths>stems. Drought stress caused greater alkaloid increases both in field and environmental chamber studies than did any other factor. In Australia, toxicity frequently occurs after severe drought, while in the southeastern U.S. drought is less frequent and severe. Also, pasture composition in the southeastern USA is more diverse, a factor known to lessen toxicity potential probably by dilution. In addition, cattle (which are less susceptible to toxicity than sheep) predominate on pastures in this region, and the chronic form of toxicity occurs only in Co deficient areas, a condition not prevalent here. It is concluded from comparisons to conditions in Australia that the probability of toxicity to grazing animals due to high alkaloid concentrations in P. aquatica in the southeastern U.S. is low, and that selection for low alkaloid types is presently unnecessary.
Influence of Percent NO3−/NH4+ on Growth, N Absorption, and Assimilation by Lima Beans in Solution Culture1
Authors: McElhannon William S. , Mills Harry A. 
Published: July 2010

AbstractApplication of the appropriate quantity and form of N in proportion to the rate of plant uptake and assimilation could significantly increase the utilization of applied N fertilizers. The objective of this study was to determine the influence of various percentages of NO3− to NH4+ and N concentration on N absorption, assimilation, growth, and yield for lima beans (Phaseolus lunatus L.) when grown in solution culture. Nitrogen was supplied as Ca(NO3)2 and/or (NH4)2SO4 at three N concentrations and five percentages of NO3− to NH4+. Peak absorption periods for NO3− and NH4+ were observed when NH4+ supplied 50% of the N. Two peak absorption periods for NO3− occurred, the first at the initiation of inflorescence and the second during pod filling. Peak periods of NH4+ absorption occurred during initiation of the inflorescence, pod development, and pod filling.Dry weights of all plant parts were consistently higher when NO3− was 75% or more of the N. Lima bean root morphology was altered at all N concentrations when NH4+ was more than 50% of the N. Plant N content was highly influenced by the form and level of N available for assimilation and may not be an accurate indicator of the N available for pod development.
Effect of Thatch on Residual Activity of Nonselective Herbicides Used in Turfgrass Renovation1
Authors: Hurto K. A. , Turgeon A. J. 
Published: July 2010

AbstractParaquat (1,1′‐dimethyl4,4′‐bipyridinium ion) and glyphosate (N‐[phosphonomethyl]glycine) are used for controlling existing vegetation in turfgrass renovation programs. While these nonselective herbicides are rapidly inactivated in many soils, the effect of a thatch layer at the soil surface on the residual activity of these herbicides has not been reported. The purpose of this study was to determine the effect of thatch on the residual activity of paraquat and glyphosate as it affects the establishment of perennial ryegrass (Lolium perenne L.) from seed.Paraquat and glyphosate were applied to Kentucky bluegrass (Poa pratensis L.) turf growing on an Aquic Arquidoll (Flanagan silt loam) at thatchy and thatchfree sites. Establishment of perennial ryegrass on paraquat‐treated thatchy sites was inhibited due to herbicide residues in the thatch. Modification of the thatch by soil incorporation following core cultivation, or removal of the thatch layer by vertical mowing, significantly improved the percent cover of ryegrass on these sites. Glyphosate showed no adverse affects on perennial ryegrass development. Placement of clipping debris containing paraquat residues onto the soil surface inhibited emergence of perennial ryegrass and Kentucky bluegrass in greenhouse studies. Adsorption of paraquat by thatch was rapid, but the tenacity with which it was adsorbed appears to differ from soil as evidenced by field and laboratory studies.
Selection for Aluminum Tolerance in Soybeans Based on Seedling‐Root Growth1
Authors: Hanson W. D. , Kamprath E. J. 
Published: July 2010

AbstractLaboratory techniques for screening soybean (Glycine max (L.) Merrill) genotypes for tolerance to Al would facilitate breeding programs for areas where AI toxicity limits soybean production. Genotypes from a broad‐base soybean population were screened For Al tolerance based on root growth rate of 5‐day‐old seedlings grown in solutions containing 0.4 ppm Al and 10 ppm Ca (pH 4.6). The selections were intermated to produce a second cycle. Three cycles of divergent selection were completed. The changes associated with selection were evaluated in laboratory studies and in greenhouse studies using Lynchburg sandy loam soil (Aeric Paleaquult).Tolerance to Al as measured by root growth rates proved to be heritable (0.67) with responses in each cycle of selection; however selections completely tolerant to 0.4 ppm Al in solution were not obtained. When high quality seed was used, genetic differences for tolerance were not affected by the environment used for seed production. Selection based on seedlings from individual plants was feasible. Genotypes selected for Al tolerance had less reduction in growth in soils with high exchangeable Al saturation than non‐tolerant selections; however, the differences were not as distinct as that found for the seedling root‐growth studies. Divergent selections had similar levels of metabolic intermediates in the root tips when seedlings were grown in 0 ppm Al, but pyruvate and ATP levels increased significantly under Al stress for the tolerant but not the non‐tolerant selections. Selection for Al tolerance based on growth of 5‐day‐old soybean seedlings in 0.4 ppm Al apparently identified genetic differences for tolerance in established plants as well as tolerance which appeared unique to the seedling stage.
Field Evaluations of the Herbicidal Effects of Fluridone on Two Soils1
Authors: Banks P. A. , Merkle M. G. 
Published: July 2010

AbstractThe selective control of perennial weeds in cotton (Gossypium hirsutum L.) with soil applied herbicides has been difficult to achieve with currently available chemicals. Also, the long‐term use of the dinitroaniline herbicides in cotton has resulted in a shifting of the weed spectrum to species which are resistant to these herbicides. New herbicides are needed to control these weed problems. The purpose of this study was to evaluate fluridone {l‐methyl‐3‐phenyl‐5‐[3‐trifluoromethyl)phenyl] ‐4(lH)‐pyridinone}, a newly developed soil applied herbicide, for effectiveness in the control of various annual and perennial weeds found in cotton. Fluridone, at several rates, was applied preplant incorporated or preemergence to Miller clay, a fine, mixed thermic vertic Haplustolls, and Lufkin fine sandy loam, a fine montmorillonitic, thermic vertic Albaqualfs, in the springs of 1976, 1977, and 1978 and in the fall of 1977. Weed control evaluations in cotton were made periodically after application. Spring applications of 0.45 kg/ha or higher effectively controlled broadleaf weeds for the growing season. Fluridone at 0.45 and 0.90 kg/ha effectively controlled rhizome johnsongrass [Sorghum halepense (L.) Pers.] 2 of 3 years evaluated. Season‐long control of yellow nutsedge (Cyperus esculentus L.) in a sandy loam soil was observed with preplant incorporated and preemergence rates of 0.90 kg/ha. Phytotoxic effects of fluridone residue were noted in a sandy loam soil one year after treatment but these effects were not as evident in the clay soil. Fluridone applied in the fall provided variable weed control the following spring depending upon soil type, weed density, and weed species present. Incorporation of the fall treatments increased the effectiveness of fluridone on annual grasses in the sandy loam soil. These experiments determined that fluridone could effectively control yellow nutsedge, rhizome johnsongrass, and many annual weeds in cotton at rates above 0.45 kg/ha but the residue of this treatment may limit the use of rotational crops the following year.