bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Study of Certain Nutritional Requirements for Tifgreen Bermudagrass (Cynodon dactylon × C. transvaalensis L.) Utilizing a Hydroponic System1
Authors: Menn Wallace G. , McBee George G. 
Published: July 2010

AbstractTifgreen bermudagrass was grown under greenhouse conditions on a modified hydroponic system and subjected to various levels of N, P, and K. Characteristic deficiency symptoms were induced for each element being studied. Tissue levels of each element were related to aesthetic value ratings, thus indicating the point at which each elemental deficiency might begin to appear. These relationships lend themselves to predicting the occurrence of nutrient deficiency symptoms in Tifgreen bermudagrass based on tissue analysis.Noticeable N‐deficiency symptoms occurred as the tissue level dropped below 22,500 ppm. A P deficiency was observed when the content of this element dropped below 2,000 ppm; however, further investigation is needed concerning the effects of P on Tifgreen nutrition. Growth suppression occurred under high P treatments. Appearance of K deficiency symptoms occurred as the tissue level of this nutrient dropped below 18,000 ppm.
Effect of Soil Temperature, Strength, and pH on Cotton Seedling Root Elongation1
Authors: Pearson R. W. , Ratliff L. F. , Taylor H. M. 
Published: July 2010

AbstractCotton (Gossypium hirsutum ‘Empire’) seedlings were grown in glass‐fronted boxes in a growth chamber with varying soil temperature, pH, and compaction levels. Root elongation rate increased rather gradually as temperature increased, reaching a maximum at 32 C, then falling sharply as temperature was increased further. The effect of temperature was amplified at low levels of soil strength and at high pH. Temperature interacted with both strength and acidity on root elongation rate, but the effects of soil strength and acidity on roots were exerted independently.
Influence of Simazine on Crude Protein and Cellulose Content and Yield of Forage Grasses1
Authors: Allinson D. W. , Peters R. A. 
Published: July 2010

AbstractConditions evaluated the influence of sub‐herbicidal applications of 2‐chloro‐4,6‐bis(ethylamino)‐s‐triazine (simazine) on the crude protein content and yield of several forage cultivars. In the greenhouse significant increases in percent crude protein and, generally, decreases in both dry matter yield and percent cellulose occurred when ‘Kenwell’ and ‘Kentucky 31’ tall fescue (Festuca arundinacea Schreb.), ‘Climax’ timothy (Phleum pratense L.), common perennial ryegrass (Lolium perenne L.), annual ryegrass (Lolium multiflorum Lam.), an allotetraploid ryegrass (Lolium sp.), and several Lolium‐Festuca synthetics were treated with simazine. Significant simazine × cultivar Interactions occurred. Tall fescue gave increased yields of crude protein without sacrificing yields of dry matter. Under field conditions reed canarygrass (Phalaris arundinacea L.), treated at five nitrogen (N) levels — 0, 56, 112, 224, and 448 kg/ha — was sprayed with simazine at rates of 0, 0.07, 0.14, 0.28, and 0.56 kg ai/ha on two dates. Three harvests were taken. Simazine and N effects were significant (P<0.01) with respect to dry matter yield. Increased levels of crude protein were evident as a result of simazine application in the first harvest and at the high N level in the second. Increased yields of crude protein were obtained at the 224 kg N/ha level as a result of simazine application compared to controls.
Performance of Five Maize Hybrids in Varying Plant Populations and Row Widths1
Authors: Hunter R. B. , Kannenberg L. W. , Gamble E. E. 
Published: July 2010

AbstractFive short‐season maize (Zea mays L.) hybrids were grown in 91‐cm and 46‐cm rows at populations of 48,000, 62,000 and 72,000 plants per hectare. The five hybrids responded similarly to changes in population density and distribution. All hybrids increased in grain yield with each increase in population and gave small but significant yield increases to narrowing the row width. Leaf area index (LAI) increased with increasing plant population or decreasing row width. The LAI values, even at the highest population, were much lower than those usually reported as giving maximum grain yield. This suggests that for short‐season hybrids the plant densities presently being used under standard production practices are too low to give maximum grain yields or to detect hybrid by population interactions for yield.
A Convenient Method of Placing Radioactive Substances in Soil for Studies of Root Development1
Authors: Jacobs E. , Atsmon D. , Kafkafi U. 
Published: July 2010

AbstractAqueous radioactive solution is placed into medical gelatine capsules which are then quickly frozen over dry ice. The frozen capsules are dropped into holes of various known depths, and root growth to those depths is timed by detection of radioactivity in the leaves.
Effects of Time and Height of Cut on Rooting Activity of Merion Kentucky Bluegrass as Measured by Radioactive Phosphorus Uptake1
Authors: O'Donnell J. L. , Love J. R. 
Published: July 2010

AbstractRadioactive phosphorus provides a means by which the depth and lateral extent of ‘Merion’ Kentucky bluegrass (Poa pratensis L.) rooting can be measured over the growing season under field conditions. Each 15.2‐cm (6‐inch) depth increment, irrespective of the height of cut, was found to have 1.5 to 3 times as much root activity as the increment immediately below it. The depth of rooting activity was least in the spring (May) and increased to a maximum in the fall (October). The relative lateral distribution of root activity for both heights of cut was approximately 62, 27, 8, and 2% of the total activity for each 5.1‐cm (2‐inch) lateral strip from the line of injection. The lateral extent was least in the spring and greatest in the fall. Throughout the growing season there was more total root activity with the 4.4‐cm (1 ¾‐inch) cutting height than with the 2.2‐cm (7/8‐inch) cutting height. In comparison to the radioactive phosphorus method, the physical measurement of roots tends to overestimate the importance of the roots above 20.3 to 25.4 cm (8 to 10 inches) and underestimate the importance of the roots below this depth.
Oxygen Diffusion in the Soil‐Plant System I. A Model1
Authors: Luxmoore R. J. , Stolzy L. H. , Letey J. 
Published: July 2010

AbstractA model for steady state, isothermal oxygen diffusion into a cylindrical root surrounded by a water film of uniform thickness is proposed. Equations are developed which account for longitudinal oxygen flux through the intercellular gas spaces, radial flux through the water film, and a respiratory oxygen sink which is defined as a function of oxygen concentration.A method of computer analysis is outlined whereby the law of continuity is applied sequentially to small sections of root, such that the amount of oxygen diffusing into a section is equated with the oxygen diffusing out plus the respiratory consumption. The solution for the model defines a series of oxygen concentrations along the root length. From these data the amount of oxygen consumed in respiration which diffuses into the top of the root (plant aeration) and the amount diffusing radially from the soil (soil aeration) may be calculated, and effects of soil and plant characteristics examined.
Effect of Ethrel on Growth and Yield of Soybeans
Authors: Slife F. W. , Earley E. B. 
Published: July 2010

AbstractEthrel sprayed on plants of ‘Amsoy’ 1.12, and 2.24 kg/hectare at six stages of development caused a reduction in plant height, percent three‐ and four‐seeded pods per plant, weight per 100 seed, and yield of seed per hectare. Percent moisture, protein and oil of mature seed were not appreciably affected by the treatments. The anti‐lodging effect of Ethrel is discussed.
Effect of Time and Rate of N Applications on Yield, Nutritive Value Index, Crude Protein, and Nitrate Content of Bromegrass1
Authors: Kin W. K. Look , MacKenzie A. F. 
Published: July 2010

AbstractThe influence of pre‐winter, spring, summer, and fall applications of N on yield and quality of bromegrass was studied over a 12‐month period on two Quebec soils. N applications increased the yield of dry matter, digestible energy (Yield‐NVI), and crude protein significantly (5%) for each increment of 112 kg N/ha. There was no significant difference among pre‐winter, spring, and summer applications of N. Mitscherlich and multiple regression equations indicated that dry matter yield of bromegrass could be increased by rates of N above 336 kg/ha.N applied prior to any growth period did not affect the NVI of bromegrass but the crude protein and NO3 contents were significantly increased in the resulting harvested material.N‐fertilized bromegrass at the 336 kg/ha level gave comparable yields of dry matter and digestible energy to alfalfa‐brome pastures.
Differential Response of Navy Beans (Phaseolus vulgaris L.) to Zinc. I. Differential Growth and Elemental Composition at Excessive Zn Levels1
Authors: Polson D. E. , Adams M. W. 
Published: July 2010

AbstractSaginaw and Sanilac navy beans (Phaseolus vulgaris) were grown at various combinations of high and normal levels of Zn, Cu, Fe, and Mn in sand culture. Saginaw variety grew normally at 5.0 ppm Zn, while the growth of Sanilac was extremely reduced. This difference was manifested in plant height, leaf number, and root and shoot weight. In addition, a differential Fe‐Cu interaction induced by high Cu levels was observed.These differences apparently were not related to differential uptake or distribution of the nutrients, since the differences in elemental composition of the two varieties did not seem to be of sufficient magnitude to be biologically significant.The Saginaw‐Sanilac nutrient interaction relationship is proposed as a valuable system for the study of nutrient utilization since these two varieties differ in their tolerance to high as well as low levels of Zn and other unbalanced micronutrient conditions.
Effect of Picloram on Growth and Protein Levels in Herbaceous Plants1
Authors: Baur J. R. , Bovey R. W. , Benedict C. R. 
Published: July 2010

AbstractWe applied 4‐amino‐3,5,6‐trichloropicolinic acid (picloram) to eight species of herbaceous plants 14 days after planting. Analysis of aerial portions 21 days after planting revealed a significant stimulation in fresh weight of corn, sorghum, cotton, cowpea, and soybean treated at from 0.25 to 0.50 ppb, and wheat at 100 ppb. Significant stimulation in dry weight was noted in corn, sorghum, cotton, and soybean at 0.25 ppb, and cowpea at 1.0 ppb. Significant decreases in fresh and dry weight occurred in corn, wheat, and sorghum at 1000 ppb, and all dicot species at 100 ppb. Herbicide treatments had no effect on the dry weights of rice and wheat, or fresh weight of rice. Herbicide treatments caused reduction in soluble protein concentrations in all monocot species and sunflower. Significant increases in soluble protein occurred at 1.0 and 0.25 ppb in cotton and cowpea, respectively.
Characterizing Soil Aeration Under Changing Soil Moisture Conditions for Bean Growth1
Authors: Dasberg S. , Bakker J. W. 
Published: July 2010

AbstractAn attempt was made to evaluate different soil aeration indices as related to plant growth during fluctuations in soil moisture content. Beans (Phaseolus vulgaris var. ‘Dubbele Witte’) were grown in soil at different aeration conditions obtained by changing bulk density (1.30 and 1.38 g cm‐3), irrigation frequencies (3 to 11 days between irrigations), and O2 concentrations at the soil surface (11% vs 21%). Frequent measurements were taken of O2 and CO3 concentrations of the soil air, oxygen diffusion rate (ODR), and redox potential and a continuous record was kept of soil air content by pot weighings.After each irrigation, the O2 concentration of the soil air decreased to less than 10% and 5%, respectively, for O2 concentrations at soil surface of 21% and 11%. No complete recovery to the soil surface values was obtained, especially with frequent irrigations. The CO2 concentration of the soil air was never high (6.5% maximum) because of the high solubility of CO2 in the irrigation water.The redox potentials measured did not show any relationship with air content or with 02 concentration. The ODR measurements were quite variable, the mean values per pot all dropped below 0.2 µg cm‐2in‐1 after irrigation.Vegetative growth and dry matter production were affected strongly by bulk density and irrigation frequency (yields ranged 4 to 16 g dry matter per plant). Total root production was hardly influenced, but the depth of root penetration was affected strongly by these aeration treatments. Lowering the O2 concentration at the soil surface from 21% to 11% had no significant effect on plant growth.Comparing the measured aeration indices (02 concentration, ODR, and air content), the mean daily air content gave the best correlation with plant growth (r = 0.82). A continuous record of soil air content seems a good index for evaluating aeration under changing soil moisture conditions.
Growth of Cotton Seedlings in Relation to Maximum Daily Plant‐Water Potential1
Authors: Jordan Wayne R. 
Published: July 2010

abstractA pressure chamber technique was used to evaluate the relation between leaf‐water potential (leaf Ψw) and growth of cotton (Gossypium hirsutum L.) seedlings under greenhouse conditions. A water potential gradient of about 5 bars developed from plant top to bottom by early afternoon, but disappeared after several hours of darkness. A diurnal change of about −12 bars occurred during one day of a drying cycle. Maximum leaf ΨW were reached just prior to sunrise. Growth processes depending largely on cell expansion for expression were affected at identical water deficits during the drying cycle. Increases in plant height, in leaf area, and in fresh weight were inhibited when potentials above −8 bars were not reached for a portion of each day. Predawn wilting was not observed until the eighth and final day of the stress period, corresponding to a leaf ΨW of −26 bars.
Differential Responses of Sorghum Varieties to Picloram1
Authors: Scifres C. J. , Bovey R. W. 
Published: July 2010

Abstract‘Pioneer 820’ seedlings were the most tolerant of seven sorghum (Sorghum bicolor (L.) Moench.) varieties to pre‐ or postemergence irrigation and to postemergence sprays with various concentrations of 4‐amino‐3,5,6‐trichloropicolinic acid (picloram). Response to the herbiside varied widely among varieties. Significant increases in dry weight of Pioneer 820, ‘RS‐625’, and ‘PAG‐665’ occurred when treated preemergence with irrigation water containing 0.5, 1, and 2 ppm of picloram whereas ‘GA‐615’, ‘RS‐671’, ‘Tophand’, and ‘RS‐626’ were reduced in growth by these concentrations. Dry weights of Pioneer 820 and RS‐625 were increased by irrigation water containing .001 to .005 ppm of picloram applied postemergence or when treated with sprays containing 0.035 to 0.7 kg/ha. Tophand was the least tolerant of picloram regardless of method of application. Varieties intermediate in susceptibility to picloram such as GA‐615, RS‐671, and RS‐626 tolerated the low concentrations used with the various treatment methods, but the higher concentrations often reduced seedling growth.
Dryland Evaporative Flux in a Subhumid Climate: I. Micrometeorological Influences1
Authors: Ritchie Joe T. 
Published: July 2010

AbstractDaily values of the major energy balance components were determined throughout complete growing seasons of dryland cotton and grain sorghum in Central Texas. Daily net radiation was found to be partitioned primarily between evaoprative flux and sensible heat flux. When crop canopies covered at least 45% of the ground surface and plant evaporation was not limited by soil water, daily net radiation was approximately equal to daily measured evaporation. Before a crop cover was established, evaporation was highly dependent on the water content of the surface soil and the fractional crop cover. For both crops, when water was depleted from the soil to the extent that plant evaporation began to be limited, daily evaporative flux decreased within 10 days to approximately half the daily net radiation. Diurnal variation in the evaporative flux during plant water stress was approximately proportional to net radiative flux, with the proportionality principally determined by the degree of soil water availability and the magnitude of the net radiation.Seasonal variation in the net radiation was influenced primarily by the solar radiation and the surface reflectance (albedo). The seasonal albedo variation depended primarily on degree of plant cover, ranging from 0.055 over practically bare, freshly plowed, black clay soil to approximately 0.23 over a practically complete cover cotton canopy. This result suggests a possibility for water conservation by increasing the surface albedo during the part of the growing season when wet topsoil is exposed to direct radiation. Closer row spacing and higher plant populations should help in achieving this effect.
Serogroups of Rhizobium japonicum in Soybean Nodules Sampled in Iowa1
Authors: Ham G. E. , Frederick L. R. , Anderson I. C. 
Published: July 2010

AbstractSerogroups of Rhizobium japonicum present in the nodules of soybeans and their relationship to soil properties were studied on 613 nodule samples obtained at 75 locations during 1965 and 1966. The homogenized nodule suspensions were typed serologically by a quick agglutination test using somatic antisera of cultures of R. japonicure representing seven serogroups. Only 2.8% and 1.1% of the nodules tested failed to react with one of the seven antisera in 1965 and 1966, respectively.R. japonicum serogroup 123 was the dominant serogroup found in soybean nodules on soils below pH 7.5, while serogroup 135 dominated when the soil pH was greater than 7.8. Individual serogroups were related to at least 2 and as many as 6 soil properties. In 1966, 81% of the variation in the occurrence of serogroup 135 was attributed to soil pH. Relating the occurrence of serogroup 135 to all soil properties accounted for 84% of the variation or only 3% more than pH alone. Less of the variation in other serogroups was attributed to soil properties.
Sites of Iron Reduction in Soybean Plants1
Authors: Ambler J. E. , Brown J. C. , Gauch H. G. 
Published: July 2010

AbstractReduction of iron (Fe3+ → Fe2+) at the root of Glycine max. (L.) Merrill var. Hawkeye soybean was studied to identify areas of reduction in the root. Sites of iron reduction were indicated by the formation of a Prussian or Turnbull's blue precipitate. This blue precipitate formed whenever the iron in either FeEDDHA or potassium ferricyanide was reduced by the plant. Where FeEDDHA and potassium ferricyanide were supplied together in the nutrient solution, a blue precipitate appeared in epidermal areas. This precipitate appeared in the endodermal areas of the root when FeEDDHA was supplied to the plant 20 hours before placing them in a ferricyanide solution. Reduction was most pronounced between the regions of root elongation and root maturation at both the epidermis and the endodermis. Reducing capacity was greatest in the young lateral diarch roots indicating that these roots contribute significantly to the ability of the plant to take up iron. A reductant which exuded from the roots of an irondeficient plant was capable of reducing approximately 360 µg of inorganic iron. The ability of some plants to reduce iron may partially explain why they can obtain iron from synthetic chelates and can utilize iron in calcareous soils more effectively than other plants.
Molybdenum Accumulation by Forage Plants1
Authors: Jensen E. H. , Lesperance A. L. 
Published: July 2010

AbstractMolybdenum accumulation by forage plants was affected by its concentration in a neutral soil, by plant species, and by depth to water table. Accumulation by Medicago sativa L. and Festuca arundinacea Schreb. increased 5.2 and 3.5 ppm, respectively, for each kg/ha Mo added to the soil.Molybdenum accumulation varied significantly among the 25 forages tested. Legumes generally accumulated more Mo than grasses did. Forage from Lotus sp. had the highest concentration of Mo, and Trifolium sp. ranked next in accumulation of this element. Twelve grasses and Carex sp. are classified as low Mo accumulators.Depth to water table was associated with Mo accumulation during 2 of 3 years. Forage grown where the water table was near the soil surface contained more Mo than where depth to water table was greater.
Evaluation of Rhizobium japonicum Inoculants in Soils Containing Naturalized Populations of Rhizobia1
Authors: Ham G. E. , Cardwell V. B. , Johnson H. W. 
Published: July 2010

AbstractAn important question in current soybean (Glycine max (L.) Merrill) production is whether inoculation is beneficial when seed is planted in soils where effectively nodulated plants have been produced previously. These studies were conducted to measure the effective of inoculating soybeans with commercial cultures of R. japonicum on seed yield and protein percentage when soybeans were grown on soils which had grown nodulated soybeans previously.Paired samples of different lots of soybean seed taken before and after commercial inoculation with R. japonicum were planted at two Minnesota locations in 1967. More extensive studies were conductedi in 1968 at five locations in cooperation with various inoculant companies. Seed from a common lot was sent to the participating companies to be inoculated. Two treated samples and an uninoculated check were returned from each company. Two samples were treated immediately prior to planting with humus samples from each inoculant company. Three humus cultures of single strains of R. japonicum, selected from the more effective strains in an inoculation study on rhizobia free soils in Minnesota, also were used as inoculants.Soybean seed yields and seed protein percentage were not significantly increased by inoculating soybean seeds with Rhizobium japonicum at planting time. The uninoculated checks were adequately nodulated by rhizobia which were in the soil from previous soybean crops. Serotyping of single strain inoculants indicated a substantial range of recovery (0–17%) depending on the strain and location.
Effects of Leaf Orientation on Leaf Resistance to Water Vapor Diffusion in Soybean (Glycine max L. Merr) Leaves1
Authors: Stevenson K. R. , Shaw R. H. 
Published: July 2010

AbstractSoybeans (Glycine max L. Merr) were grown in 75‐liter potometers within an area that could be covered by a movable shed during rainfall periods. Leaves on 3 of 10 plants in each potometer were tied upright, while leaves on the other plants were left naturally exposed. Two soil moisture levels were used.The leaf resistance values for upright leaves were less than those of naturally exposed leaves on 8 of the 9 sunny days and averaged 1.38 sec/cm less. Similarly, leaf temperatures were less for upright leaves. On overcast days, leaf orientation had no effect on leaf resistances or temperatures.These differences were measured on individual plants and not on whole canopies. The data do suggest, however, that less leaf resistance to water vapor diffusion and lower temperatures of leaves would occur in soybean canopies with upright leaves and that this characteristic could be a worthwhile objective in breeding soybean varieties with tolerance to moisture stress.