bluuebunny/crossref_metadata_2025_split huggingface dataset:
Turfgrass Wear Tolerance Mechanisms: II. Effects of Cell Wall Constituents on Turfgrass Wear Tolerance1
Authors: Shearman R. C. , Beard J. B. 
Published: July 2010

AbstractThis investigation was conducted to assess the relationship of cell wall constituents of seven cool‐season turfgrass species to wear tolerance. The turfgrass literature contains no data of this nature. The percent total cell wall (TCW), lignocellulose (ADF), cellulose, hemicellulose, and lignin were determined on a gram dry weight and mg/dm2 basis. Species differed significantly in cell wall constituents for both methods of determination. The relative ranking of the species based on the content of various cell wall constituents expressed on a gram dry weight basis was as follows: Cascade chewings fescue (Festuca rubra var. commutata Gaud) > Pennlawn red fescue (F. rubra L.) and Kentucky 31 tall fescue (F. arundinacea Schreb.) > Manhattan perennial ryegrass (Lolium perenne L.) > Merion Kentucky bluegrass (Poa pratensis L.) > Italian ryegrass (L. multiflorum Lam.) > rough bluegrass (P. trivialis L.). However, the species ranked as follows when the cell wall components were expressed on mg/dm2 basis: Kentucky 31 > Manhattan and Merion > Pennlawn and Italian ryegrass > Cascade > rought bluegrass. Cell wall constituents reported on a g/dry wt. basis were not correlated individually to wear tolerance. However, the combined effects of TCW, ADF, cellulose, and lignin accounted for 96% of the observed wear tolerance variation among the seven turfgrass species studied. TCW, ADF, cellulose, and hemicellulose contents expressed as mg/dm2 were significantly correlated individually to wear tolerance. Their combined effects accounted for 97% of the variation in inter‐species wear tolerance. Total cell wall content expressed on a mg/dm2 basis accounted for 98% of the variation in wear tolerance among the seven turfgrass species.Cell wall constituents were found to increase significantly with plant maturity, with the exception of hemicellulose. TCW increased significantly during the period from July to September, but declined in all species during October. The TCW, ADF, cellulose, hemicellulose, and lignin contents of leaf blades were significantly less than for the leaf sheath for all species.
Reflectant Induced Modification of Soybean Canopy Radiation Balance. II. A Quantitative and Qualitative Analysis of Radiation Reflected from a Green Soybean Canopy1
Authors: Lemeur Raoul , Rosenberg Norman J. 
Published: July 2010

AbstractThis report is one of a series of papers describing reflectant‐induced modification of the canopy radiation balance. Water‐saving effects are expected since net radiation, which is the driving force for evapotranspiration, should be reduced by the reflectant treatment. The experiments were planned to establish reflection patterns over soybeans (Glycine max. [L.] Merr. ‘Amsoy’) at Mead, Nebraska.This study was undertaken to determine reflection coefficients at various solar elevations and at two values of leaf area index (LAI = 2.5 and 5.5) of a normal, unreflectorized soybean canopy so as to develop a base line against which to evaluate the effectiveness of various factorial treatments of reflectant materials, times and amounts of application. Therefore, net radiation, incoming and reflected radiation (300 to 3,000 nm) and the corresponding energy spectra within the 380 to 1,550 nm wavelength band were measured using a net radiometer, an upright and inverted pyranometer and a spectroradiometer, respectively.The shortwave reflection coefficient, αs, as well as the coefficients for photosynthetically active radiation α(PAR) and near‐infrared radiation α(NIR) remained nearly constant throughout most of the day, but increased significantly when solar altitude was less than 35°The dependence of albedo on LAI was a function of wavelength. At medium to high solar elevations α(PAR) decreased with increasing LAI while α(NIR) increased sharply. At lower solar altitudes both α(PAR) and α(NIR) increased with increasing LAI. The radiant energy reflected from the soybean crop showed a strong spectral shift toward NIR wavelengths with the increase in leaf area.
Estimating Evaporation and Transpiration from a Row Crop during Incomplete Cover1
Authors: Tanner C. B. , Jury W. A. 
Published: July 2010

AbstractIn order to model the evapotranspiration (ET) from a crop with incomplete cover, the evaporation (E) is estimated separately from the transpiration (T) since E and T usually do not vary proportionately. Our objective was to develop and test an ET model based on the “potential” ET formula of Priestley and Taylor and ‘potential’ E and T estimates that are consistent with the potential ET estimate. When E is less than the potential E (the falling rate phase), it is estimated by two approaches based on E falling as t½; however, the model assumes transpiration is at the ‘potential’ rate.ET estimates during cover development of potato (Solanum tuberosum L. ‘Russet Burbank’) for 2 years were compared with lysimeter measurements. The standard error of estimate varied from 0.40 to 0.94 mm/day depending on the method for estimating E. The estimate of cumulative ET for 4 weeks varied from the lysimeter a maximum of 1 cm in 9.7 cm ET.
Planting Corn in Sod and Small Grain Residues with Minimum Tillage1
Authors: Robertson W. K. , Lundy H. W. , Prine G. M. , Currey W. L. 
Published: July 2010

AbstractHigh costs of labor, fuel, and machinery; need to conserve moisture; loss of soil from erosion; and desire to double crop are some of the factors considered in the trend towards no‐tillage methods of planting crops.No‐tillage planting of corn in Pensacola bahiagrass (Paspalum notatum Flugge) sod and small grains such as rye (Secale cereale L.) was compared to conventional planting “rotavating, disking, and planting” for 3 years on Lakeland fine sand (Typic Quartzipsamment).When Pensacola bahiagrass was treated with paraquat + residual herbicide before planting corn by the notillage method, it recovered quickly and competed with the corn for water and nutrients. Corn (Zea mays L.) planted no‐tillage had lower yields than when conventionally planted, but after corn harvest the bahiagrass growth was adequate for grazing. Adding extra N to the no‐tillage corn increased yields of both corn and grass. Corn under no‐tillage in rye treated with paraquat + residual herbicides generally yielded about the same as conventionally planted corn.Pensacola bahiagrass when treated with glyphosate in combination with other herbicide was almost all killed and offered little competition to the corn. Forage yield in the fall was only 37% of yield after paraquat‐residual herbicide application.The effectiveness in controlling broadleaf weeds with atrazine, cyanazine, alachor, linuron, and combinations of these herbicides varied seasonally, but had no significant effect on corn yields. Weed growth at corn harvest was considerably less on the no‐tillage plots; however, after 3 years of continuous no‐tillage corn perennial weeds were beginning to appear while few perennial weeds were observed in the conventionally planted corn.
Comparison of Simulated and Measured Nitrogen Accumulation in Burley Tobacco1
Authors: Zartman R. E. , Phillips R. E. , Leggett J. E. 
Published: July 2010

AbstractEfficient utilization of N fertilizers by plants is important for scientific, economic, and environmental reasons. The objectives of this experiment were (1) to experimentally evaluate the simultaneous mass flow and diffusion of NO3‐N to tobacco roots and (2) to compare the calculated accumulation of N in tobacco, the root of which was assumed to be a perfect sink for NO3‐N (Model I), or flux of NO3‐N into the root which was assumed to be proportional to concentration of NO3‐N at the root surface (Model II), to measured accumulation of N in Burley tobacco grown under field conditions. Model I overestimated accumulation of N an average of 52%. Model II underestimated accumulation an average of 26%. The proportionality constant, k, assumed by Model II, was found to be 4.27 ✕ 10−7 cm2 sec−1 throughout the growing season, except when moderate plant water stress was experienced by the plant. The data show that the accumulation of N by Burley tobacco was proportional to the concentration of NO3‐N in the soil solution.
Evaluation of Sulfur‐coated Urea (SCU) Applied to Irrigated Potatoes and Corn1
Authors: Liegel E. A. , Walsh L. M. 
Published: July 2010

AbstractExcessive rates of soluble N fertilizers are sometimes used on irrigated sands in Central Wisconsin to compensate for loss of some of the applied N by leaching. Use of a slow‐release form of N or several small applications of a soluble N fertilizer may eliminate some leaching and subsequent loss of NO3‐N. This study was designed to evaluate these methods of reducing N losses by measuring yield and recovery of applied N by potato (Solanum tuberosum L.) tubers and corn (Zea mays L.) grain. Supplemental N treatments applied each year for 3 years were as follows: 1) urea in a single or split application, 2) SCU impregnated with a wax coating, and 3) SCU with only a sulfur coating.Recovery of applied N by tubers from a single urea application was extremely low in 1972 due to severe leaching induced by abnormally high precipitation. Slow‐release SCU carriers produced higher yields and N recovery that year because their slow dissolution reduced leaching losses of N. However tuber yields and recovery of N from urea treatments were greater than from SCU treatments in 1973 and 1974 because of reduced leaching those years. In addition, the supplemental N (urea or SCU) for all potato treatments was protected from leaching in 1973 and 1974 by placement of the N into a relatively dry zone of the potato hill.Corn yields and grain N recovery were similar among carriers of N in 1972 and higher from urea than SCU in 1973 and 1974. The greater recovery of N from urea by corn grain as compared to potato tubers in 1972 apparently was due to the deeper rooting of corn. Furthermore the potatoes received twice as much water by irrigation as compared to the corn.Oat (Avena sativa L.) forage yields from both trials in 1975 indicated there was greater residual N in SCU plots than urea plots due to incomplete release of urea‐N from SCU. Adequate dissolution of SCU‐N within a single growing season occurred only under severe N‐leaching conditions.
Effect of Rice Straw Incorporation on Rice Plant Growth and Nutrition1
Authors: Rao D. Niranjan , Mikkelsen D. S. 
Published: July 2010

AbstractRice (Oryza sativa L.) straw disposal by soil incorporation may have adverse effects on subsequent rice seedling growth from toxic anaerobic decomposition products and temporary immobilization of the soil mineral N. Glasshouse and laboratory studies were conducted to study the problem under conditions of direct sowing of rice.Samples of a typical rice soil, Sacramento clay, which is a very fine, montmorillonitic thermic Vertic Hapiquall, were collected. Rice straw in amounts of 0, 0.25, and 0.5% was added to soils which were incubated aerobically for 0, 15, and 30 days in a glasshouse plant growth experiment, and for 0 and 20 days in preparation for a laboratory soil incubation experiment. Nitrogen was applied at the rate of 50 ppm in the glasshouse experiment and 50, 75, and 100 ppm in the laboratory study. N was added after aerobic incubation and subsequently rice was grown for 21 days to measure seeding growth effects. The glasshouse experiment with rice cultivar ‘Earlirose’ also evaluated the production of acetic, propionic, and butyric acids, while the laboratory soil incubation experiment was for N transformation data.The results clearly indicate that when soil and rice straw were not incubated prior to planting rice seedlings, applied N was immobilized, causing inhibition of plant growth and low N content of plants. When rice straw was incubated in soil for 15 to 30 days before planting seedlings, N immobilization was reduced and plant growth was promoted. Nitrogen immobilization was observed to be the principal cause of inhibition of plant growth from added rice straw. Organic acids (acetic and propionic) were produced in amounts considered to be below the toxic concentration of plants. Butyric acid was not found in the soil extracts.
Growth of Subterranean Clover in a Range Soil as Affected by Microclimate and Phosphorus Availability. I. Field Studies1
Authors: Raguse C. A. , Evans R. A. 
Published: July 2010

AbstractRelationships between microenvironment and phosphorus availability are important to stand establishment and winter growth of introduced annual legumes in California's foothill rangelands.Ridge, furrow, north‐facing, and south‐facing microsites were established to create variations in light and temperature microenvironments in previously tilled soils of the Sobrante and Las Posas series. An additional microsite treatment, consisting of a simulated range drill seeding, with and without a litter cover, was made on adjacent untilled soil. Phosphorus rates, applied as single superphosphate, were 0, 40, 80, and 160 kg P/ha.Pellet‐inoculated seeds of subterranean clover (Trifolium subterranean L.) were sown in rows 15 cm apart perpendicular to the microsite ridges, slopes, and furrows.Soil (1 cm) and air (3 cm above soil) temperatures were monitored hourly with thermistors.Plant sampling was done at four times from November to March to determine morphological development, plant weight, and percent P per plant. At maturity, remaining plants were sampled to estimate seed production.Large diurnal temperature differences were associated with microsite treatments and were more pronounced for soil than for air.Percent P in shoot tissue generally reached highest values in January, indicating that plant growth was restricted more during winter than was P uptake. With warmer temperatures and higher light intensities in February, growth dilution resulted in a decrease in P percentage. Small modifications of microrelief significantly altered the microenvironment, especially soil temperature. Morphological development and plant weight responses were greatest on south‐facing slopes and at the highest P level. Seed production was not influenced by P fertilization.
Effect of Water Stress During Different Stages of Growth of Soybean1
Authors: Sionit Nasser , Kramer Paul J. 
Published: July 2010

AbstractThe effects on yield of controlled water stress applied at various stages of development were studied on two varieties of soybean (Glycine max (L.) Merr.), ‘Ransom’ and ‘Bragg.’ The plants were grown in a controlled environment chamber at 28/17 C with a 9‐hour photoperiod at 450 hlx and an interrupted dark period. Interruption of the dark period was suspended for 7 days to induce flowering. Groups of plants were subjected to water stress during flower induction, flowering, pod formation, and pod filling.Leaf water potential during stress fell as low as —23 bars, but after rewatering the potential of plants in all treatments returned approximately to normal. Plants stressed during flower induction and flowering produced fewer flowers, pods, and seeds than controls because of a shortened flowering period and abortion of some flowers. Stress during early pod formation caused greatest reduction in number of pods and seeds at harvest. However, yield as measured by weight of seeds was reduced most by stress during early formation and pod filling. Water stress at no stage of growth materially affected the oil or protein content of the seeds.
Root Zone pH Changes and Ion Uptake Imbalances by Triticale, Wheat, and Rye1
Authors: Mugwira L. M. , Patel S. U. 
Published: July 2010

AbstractDifferential pH induced in growth media and the ion uptake imbalances of different cultivars are important criteria of degrees of aluminum tolerance. The objective of this study was to determine if changes in pH of nutrient solutions and soil and anion‐minus‐cation (A—C) uptake from solution can be used to rank cultivars of triticale (X Triticosecale Witt Mack) of differential Al tolerance. Changes in pH induced by 11 cultivars of triticale, wheat (Triticum aestivum L.), and rye (Secale cereale L.) were measured in 1/5‐strength Steinberg solution with initial pH of 4.8 and in Al‐toxic Tatum clay loam subsoil (clayey, mixed, thermic, Typic Hapludults) at different lime rates in a growth chamber. The A—C uptake, pH, and H+ changes were measured for 4 days in a solution containing 1 × 10‐3 M KNO3 plus 2 × 10‐4 M Ca (NO3)2 initially adjusted to pH 4.65. Aluminumtolerant ‘Seneca’ and ‘Atlas 66’ wheats induced significantly higher pH in both solution and soil at low pH values of 3.84 and 4.39 than Al‐sensitive ‘Arthur’ and ‘Morion’ wheats. However, at pH 5.88 Seneca produced significantly higher pH than Atlas 66 and Monon wheats. Aluminum‐tolerant ‘6TA 298’ triticale induced the same pH in solution but higher pH in the soil than the more Al‐sensitive ‘6TA 131’ ‘6TA 385’, ‘6TA 522’, and ‘6TA 203’ triticales except at pH 5.88, when 6TA 298 and 6TA 385 gave the same pH value. Abruzzi and Vitagraze ryes gave similar pH values to Atlas 66 in solution but were less effective in raising the pH of the soil. The A—C accounted for pH changes (r = 0.731**) in solution containing KNO3 and Ca(NO3)2 and there was an approximately stoichiometric relationship between A—C and H+ changes during each of the 4 days without clear separation of the cultivars according to their differential Al tolerances. The pH changes were consistently related to Al tolerance in the Steinberg solution for wheats and in the soil below pH 4.5 for triticales and wheats.
Leaf Reflectance vs. Leaf Chlorophyll and Carotenoid Concentrations for Eight Crops1
Authors: Thomas J. R. , Gausman H. W. 
Published: July 2010

AbstractLeaf reflectance in the 0.40‐ to 0.75‐μm wavelength interval is influenced primarily by the pigments chlorophyll and carotenoid. However, the literature contains very few references to the relation between reflectance from leaves and their carotenoid content. Our objectives in this study were to determine which of three wavelengths in the visible spectral region best related leaf reflectance to total chlorophyll and carotenoid concentrations, and the relative effect of these pigments on reflectance.Hemispherical reflectances of single leaves at each of the 0.45‐, 0.55‐, and 0.67‐μm wavelengths for cantaloupe (Cucumis melo L. cv. reticulatus Naud.), corn (Zea mays L.), cotton (Gossypium hirsutum L.), cucumber (Cucumis sativus L.), head lettuce (Lactuca sativa L. cv. capitata L.), grain sorghum (Sorghum bicolor (L.) Moench), spinach (Spinacia oleracea L.), and tobacco (Nicotiana tabacum L.) were regressed on each crop's leaf total chlorophyll and carotenoid concentrations. The crops were grown in sand culture, and their leaf pigment concentrations were varied by supplying N at rates of 14, 28, 84, 140, and 196 ppm to a basic nutrient solution.Hemispherical reflectance of leaves was inversely related to each crop's leaf chlorophyll and carotenoid concentrations. However, of the three wavelengths tested, the 0.55‐μm wavelength seemed superior for individually relating the two pigments to leaf reflectance. The independent effects of carotenoid on hemispherical reflectance were small and generally not statistically significant, whereas the independent effects of chlorophyll while small were generally significant. The combined effects of these variables were highly significant and accounted for 39 to 95% of the reflectance variability.This study indicated that even though including carotenoid with total chlorophyll measurements improved the correlation of reflectance with pigment concentration, satisfactory results would be obtained by chlorophyll analysis alone.
Mechanical Scarification of Dormant Wild Rice Seed1
Authors: Oelke E. A. , Albrecht K. A. 
Published: July 2010

AbstractWild rice (Zizania aquatica L.), which formerly grew only under natural conditions until the early 1960's, is now being grown as a cultivated field crop. A 3 to 6‐month, post‐harvest seed dormancy hinders the continued development of wild rice as a field crop. Part of this dormancy is due to an impermeable pericarp. Scarification with chemicals to increase permeability has not been successful, and scraping the individual seeds to remove the pericarp above the embryo is too time‐consuming. A small rock polisher was evaluated as a scarification device in this study. Three dehulled seed lots, one from greenhouse‐grown plants and two from field‐grown plants with different harvest dates were used. Samples from each were tumbled with dry crushed granite in the polisher for varying times or scraped with a razor blade to remove the pericarp above the embryo. Laboratory and greenhouse gemination were used to measure the resulting release of dormancy. Seed tumbled in the laboratory for 1 hour gave gemination percentages in water of 44 to 60, depending on the seed lot. Scraped seed gave gemination percentages of 65 to 100 for the corresponding seed lots. Tumbling resulted in less seed injury and required less time than scraping seed. Placing tumbled or scraped seed 1.5 cm deep into soil in the greenhouse before flooding gave an average gemination percentage of only 13 compared to 64 when seed was germinated in water. Transplanting seedlings from scarified seeds germinated in water was more successful than direct planting of scarified seed to establish greenhouse stands. Use of the rock polisher significantly accelerated scarifying wild rice seed with a minimum amount of injury. This method may be adapted to other high moisture seed that requires scarification.
Testing Salt Tolerance Variability Among Tall Wheatgrass Lines1
Authors: Shannon Michael C. 
Published: July 2010

AbstractThe vague symptoms of moderate salt stress on plants and the lack of understanding about the mechanisms that confer salt tolerance have hampered efforts to develop reliable screening procedures for this trait. In the present study a screening procedure was evaluated to determine its usefulness in detecting variation among introductions of tall wheatgrass [Agropyron elongatum (Host) Beauv.]. In greenhouse sand flats, 32 lines tall wheatgrass were established and subjected to stepwise increases in salinity up to 765 meq/liter or until severe leaf damage resulted. The lines were classified into five groups based on relative leaf damage and recovery rates from salt treatment. Repeating the screening procedure on seven each of the most tolerant and most sensitive lines reaffirmed the results of the first screening. Mineral analyses indicated that tolerance was associated with restricted accumulation of Na, Ca, and Cl in the shoots. Proline and soluble sugars contributed to osmotic adjustment at high salinities, but sensitive and tolerant lines did not differ in proline content. This screening technique appears to discriminate between lines with different ion transport properties and different salt tolerances. The sensitive and tolerant lines identified may be beneficial in future breeding and physiological studies.