bluuebunny/crossref_metadata_2025_split huggingface dataset:
Vernonia anthelmintica: A Potential Seed Oil Source of Epoxy Acid. IV. Effects of Line, Harvest Date, and Seed Storage on Quantity and Quality of Oil1
Authors: White G. A. , Earle F. R. 
Published: July 2010

AbstractPre‐ and post‐frost harvested seeds of Vernonia anthelmintica (L.) Willd. lines PI 283729, VS63‐40, and VS65‐224 (pre‐frost only) were stored under continuous cold, room, and barn (ambient) conditions and sampled at 0, 48, and 96 weeks to determine the effects of storage on oil quantity and quality.Harvest date did not affect oil content. For the prefrost harvest, oil content declined with storage time, especially under room and barn conditions, but the gradual reduction was not of practical significance. The oil percentages for seeds of PI 283729 (26.6%) and VS63‐40 (29.9%) significantly exceeded that of VS65‐224 (22.0%). Seed oils of the three lines did not differ in amounts of epoxy acid or free fatty acids. Epoxy acid content declined during the period from 0 to 48 weeks and then rose from 48 to 96 weeks. Time in storage affected epoxy acid content more than storage conditions. The level of free fatty acids remained essentially unchanged during the storage period. Good quality vernonia seeds can be stored for relatively long periods without a serious reduction in oil content or quality.Poor quality oils with significantly lower levels of epoxy acid and higher levels of free fatty acids were obtained from the post‐frost harvest. The oil from PI 283729 seeds was of poorer quality than that from VS63‐40 seeds; the quality of both declined in storage at ambient temperatures.
Organochlorine Insecticide Residues in Soybean Plant Tops: Root vs. Vapor Sorption1
Authors: Beall M. Leroy , Nash Ralph G. 
Published: July 2010

AbstractSoybeans were grown in specially constructed pots to determine the amount of residue contamination in plant tops from 20 ppm surface or subsurface soil‐applied 14C‐labeled p,p'‐DDT, dieldrin, endrin, or heptachlor. Regardless of the insecticide treatment, plant tops were contaminated by both root sorption and foliar sorption of vapors emanating from the soil. Root sorption was the major source of contamination by dieldrin, endrin, and heptachlor, though vapor sorption of dieldrin was nearly as great. Foliar contamination by vapor sorption of DDT residues was nearly seven times greater than for root sorption. Foliar contamination from vapor sorption of residues from all four insecticides was near the same order of magnitude, about 6.5 ppm plant dry weight, whereas contamination from root sorption from endrin was 38, heptachlor 21, dieldrin 11, and DDT 1 ppm.Plant parts were assayed by several methods. Although residue concentrations were different for each insecticide, both the apparent plant degradation and mobility of the insecticide, or degradation products, were: DDT ≥ heptachlor > endrin > dieldrin where root sorption was the source of residue. One heptachlor degradation product, in addition to heptachlor epoxide, two endrin degradation products, and p,p'‐DDE and p,p'‐DDD were found.
Influence of Aluminum on Plant Growth and Mineral Nutrition of Potatoes1
Authors: Lee C. R. 
Published: July 2010

AbstractEight potato varieties were grown vegetatively in nutrient culture solutions to study the effect of aluminum on plant growth and mineral nutrition. The addition of 20 ppm Al to the growth medium reduced yields of plant tops and roots for all varieties. In other experiments, a differential tolerance to 1 to 5 ppm of Al was found among four potato varieties. Aluminum tolerance decreased among varieties in the order ‘Netted Gem’ > ‘Sebago’ > ‘Katahdin’ > ‘Green Mountain.’ P, Al, Mn, Fe, and Cu accumulated within plant roots grown in AI solutions while translocation of P to plant tops was depressed. Ca, Mg, and Zn absorption by plant roots was inhibited by AI. K absorption by plant roots was stimulated at low AI levels (1 to 2 ppm) but inhibited at high Al levels (5 to 10 ppm). Al tolerance among potato varieties may be related to the ability of plant roots to absorb Mg and K.
Interpreting the Rate of Change in Nitrate‐Nitrogen in Sugarbeet Petioles1
Authors: Carter J. N. , Jensen M. E. , Bosma S. M. 
Published: July 2010

AbstractNitrate‐nitrogen in sugarbeet petioles is used to evaluate current N status of sugarbeet crops. Since the NO3‐N changes rapidly during the season, better relationships are needed to interpret these data relative to sugarbeet N nutrition.Sugarbeets (Beta vulgaris, L.) were grown at four N fertilization rates and two irrigation levels to determine the root yield, sucrose percentage, sucrose yield, and N uptake in relation to the NO3‐N concentration in the petioles. NO3‐N in beet petioles increased to a peak concentration and then decreased exponentially during the two growing seasons on all treatments. The exponential decrease after the peak enables prediction of the NO3‐N in the petioles during the remainder of the growing season. This rate of change approach can be used to predict N needs when adding supplemental N for sugarbeets and to characterize the N status of soil‐crop systems.
Effect of Rotations, Tillage Methods, and N Fertilization on Winter Wheat Production1
Authors: Tucker Billy B. , Cox M. B. , Eck H. V. 
Published: July 2010

AbstractWinter wheat (Triticum aestivum L.) was grown continuously and in rotation with alfalfa (Medicago sativa L.) or grass on Pond Creek and Grant silt loams in the 64‐cm rainfall area of north central Oklahoma. Studies were conducted from 1956 through 1967. Stubble mulch and clean tillage were compared in continuous wheat and alfalfa‐wheat systems. The principal effect of alfalfa on wheat yield was to supply N. Wheat in rotation with alfalfa (3 years alfalfa, 3 years wheat) yielded 2,020 kg/ha, while continuous wheat fertilized annually with 45 kg N/ha yielded 2,180 kg/ha. Yields of wheat in a grass‐wheat rotation were inferior to those of continuous wheat plus N because of N deficiency.Without N fertilizer, clean‐tilled continuous wheat outyielded stubble‐mulched continuous wheat by 23% (clean tilled: 1,790 kg/ha; stubble‐mulched: 1,460 kg/ha). With 45 kg N/ha, the advantage for clean tillage was reduced to about 8% (clean tilled: 2,160 kg/ha; stubble‐mulched: 2,000 kg/ha). The 45 kg/ha N fertilizer rate was sufficient for near maximum wheat yields under both clean and stubble‐mulch tillage.
Diurnal Variation in Nonstructural Carbohydrates, In Vitro Digestibility, and Leaf to Stem Ratio of Alfalfa1
Authors: Lechtenberg V. L. , Holt D. A. , Youngberg H. W. 
Published: July 2010

AbstractAlfalfa (Medicago sativa L.) was sampled four times daily during first and second growths and eight times daily for three days during third growth in order to detect diurnal changes in carbohydrate constituency, in vitro digestibility, and leaf to stem ratio. The implications of these changes with regard to forage yield and nutritional value were considered.Reducing sugars and sucrose were removed from freezedried, ground material by alcohol extraction. Starch in the residue was hydrolyzed by takadiastase. Ferricyanide, resorcinol, and phenol‐sulfuric acid procedures were used to quantitatively assay sugars in the extracts. Glucose and fructose percentages increased slightly but significantly from 6 AM to 12 N and declined to 6 PM in second and third growth alfalfa. About three times as much glucose as fructose was present. Sucrose comprised less than 3% of the dry matter, but varied considerably diurnally, generally increasing from 6 AM to 6 PM. Leaf starch increased from 10.2 to 20.3% of the dry matter during daylight hours, most of the increase occurring between 9 AM and 3 PM. Stem starch remained between 4 and 5% of the stem dry matter. In general, all nonstructural carbohydrates studied began to accumulate after 6 AM. Hexoses peaked first in leaves followed by sucrose and then starch. These were depleted in the same order in the afternoon and at night. Peak levels of glucose and sucrose occurred in stems later than in leaves. Leaf stem ratio increased from 1.1 to 1.5 between morning and evening and declined at night.In vitro dry matter digestibility averaged 1.6% higher at 6 PM than at 6 AM.
Water Balance of a Seed Onion Field1
Authors: Goltz S. M. , Tanner C. B. , Millar A. A. , Lang A. R. G. 
Published: July 2010

AbstractTranspiration, evaporation, and drainage from a sparsely populated onion field were measured separately by a method which should be applicable to many row crops. Transpiration computed from measured evapotranspiration, potential evaporation, and stomatal resistances agreed well with values calculated independently from raeasured stomatal resistance, air vapor pressure, plant‐temperature and wind. Transpiration was only about 20 percent of total evapotranspiration. When the population was increased threefold to near maximum commercial density, evapotranspiration increased only about 15 percent because as transpiration increased, evaporation decreased. The portion of transpiration accounted for by each plant part was 3 percent for umbels, 42 percent for leaves and 55 percent for scapes. Drainage from this sandy soil exceeded evapotranspiration.
Radicle Elongation of Pea Seedlings as Affected by Oxygen Concentration and Gradients between Shoot and Root1
Authors: Eavis B. W. , Taylor H. M. , Huck M. G. 
Published: July 2010

AbstractPea seedlings grown in divided gas‐tight containers were arranged so that O2 concentration of soil air around the radicles could be varied independently of that around the cotyledons and plumules. When the soil around the radicle tip contained 0.21 atm O2, no significant reduction in radicle elongation rate was observed until the gas mixture surrounding the cotyledons was reduced below 0.10 atm partial pressure. Even with O2 partial pressure at 0 around the cotyledons radicle elongation rate was 50% as high as that of the controls.When O2 concentration around the radicle was varied, while that around the cotyledons remained at 0.21 atm, the radicle elongation rate at a given O2 level was markedly reduced. At zero O2 around the radicle elongation rate was only 20% of normal. It is suggested that a high diffusion impedance between internal gas channels and the relatively undifferentiated tissues near the root tip limits O2 supply to respiring tissue.
Tillage and Crop Residue Management During Seedbed Preparation for Continuous Spring Wheat1
Authors: Bond J. J. , Power J. F. , Willis W. O. 
Published: July 2010

AbstractField experiments were conducted to determine the effect of four tillage and crop residue management methods of seedbed preparation on continuous spring wheat (Triticum aestivum L.) receiving four rates of applied N. Effects of tillage and surface‐crop residues were separated by seedbed treatments of (a) conventional moldboard tillage, (b) conventional stubble mulch tillage, (c) moldboard tillage with part of the surface residue removed before and replaced after tillage, and (d) moldboard tillage with all surface residue removed before and replaced after tillage. Treatments were evaluated relative to grain yields, yield components, dry‐matter production, N uptake, soil nitrate content, soil temperature, plant water use and weed populations. for 3 of 4 years average grain yields (for all N rates) were 1,380, 1,060, 1,380, and 1,330 kg/ha for treatments a, b, c, and d, respectively. Yield reduction with stubble mulch tillage was related to poor weed control (primarily green foxtail) and not to the effects of surface residue per se. Use of fertilizer N failed to overcome yield reduction associated with stubble mulch tillage.
Effect of Nitrogen on Nodulation and Yield of Irrigated Soybeans1
Authors: Beard Benjamin H. , Hoover Richard M. 
Published: July 2010

AbstractWayne soybeans [Glycine max L. (Merrill)] were sown immediately after barley harvest in a 2 crop, 1‐year rotation experiment, to determine the effects of additions of nitrogen (as ammonium sulfate) on nodulation and yield. Treatments consisted of all combinations of: (i) barley straw residue (burned or shredded); (ii) timing of nitrogen application (before planting, at flowering or a combination); and, (iii) rates of application (0, 56, 112, 168 kg/ha of nitrogen) in a split‐split‐split design.Nodule number per plant was linearly and inversely related to rate of nitrogen application. There were fewer nodules per plant if 56 kg/ha or more nitrogen was applied at planting time, but up to 112 kg/ha did not affect nodule numbers if applied at flowering. There appeared to be more nodules per plant on plots with the straw shredded, but the differences between shredding and burning the barley straw were not significant.Even though plants on the 0 nitrogen plots were yellow‐green in early growth stages, there were no significant differences in yield due to straw treatment, timing, or rate of application of nitrogen.
Estimating Leaf Water Content by Reflectance Measurements1
Authors: Thomas J. R. , Namken L. N. , Oerther G. F. , Brown R. G. 
Published: July 2010

AbstractRegression equations expressing reflectance of incidentlight from the upper (adaxial) surface of single leaves as a function of their relative turgidity and water content were developed. Reflectance at the 1.45‐ and 1.93‐µ water absorption bands was significantly related (p = 0.01) to the leaf relative turgidity or water content. However, because of variations in internal leaf structure associated with the availability of water during leaf development, the ability to predict the leaf water status from reflectance easurements was poor. With cotton (Gossypium hirsutum L.) the greatest change in reflectance occurs when the relative turgidity is below 70% and the leaves are visibly wilted. Within the relative turgidity range, 70 to 80%, reflectance changes are small and may not be definable for predictive purposes because of variation among leaves of field‐grown cotton caused by age differences and osmotic stresses.
Effects of Photoperiod, Light Intensity, and Temperature on Vegetative Growth, Flowering, and Seed Production in Cicer arietinum L.1
Authors: Sandhu S. S. , Hodges H. F. 
Published: July 2010

AbstractSeveral diverse strains of Cicer arietinum L. were grown in growth chambers to study the effects of temperature, photoperiod, and light intensity on flowering and seed set. Plants were grown in 15, 22.5, and 30 C conditions at about 16 and 28 kilolux. Generally, plants in the high light intensity, 16‐hour photoperiod, and at 22.5 C, produced more flowers and seed than did other treatment combinations. Some strains produced flowers and set seed under short photoperiods and may have potential in breeding chickpea cultivars with wider environmental adaptability.
Estimating Leaf Area from Length Measurements for Hybrid Granex Onion1
Authors: Hoffman Glenn J. 
Published: July 2010

AbstractA logarithmic linear relationship was found between leaf length and area for onion (Allium cepa L. ‘F‐l Hybrid Yellow Granex’) grown from seed in sunlit climate chambers with controlled temperature and humidity. Atmospheric relative humidity and root medium salinity had no effect on the relationship.
Estimating Nitrogen Content of Sweet Pepper Leaves by Reflectance Measurements1
Authors: Thomas J. R. , Oerther G. F. 
Published: July 2010

AbstractA study was conducted to determine the feasibility of using spectrophotometrically measured diffuse light reflectance from top (adaxial) leaf surfaces of sweet pepper (Capsicum annum, L. var. ‘Yolo Wonder’) leaves to quickly estimate their N status. Reflectance was found to be inversely correlated (p = 0.01) with the leaf N content. Regression equations expressing reflectance as a function of leaf N content of greenhouse‐grown sweet peppers were used to estimate the N content of fieldgrown sweet peppers. The difference between Kjeldahldetermined and reflectance‐estimated N contents was less than 0.7%. The regression equation at the 550‐nm wavelength suggests that near the 4% N level a 1% change in reflectance would change the predicted N content by 0.2%. Results show that leaf reflectance can be used to quickly estimate the N status of sweet peppers.
Microclimate Modification by Slat‐fence Windbreaks1
Authors: Skidmore E. L. , Jacobs H. S. , Hagen L. J. 
Published: July 2010

AbstarctThe influence of windbreaks on the microclimate has been widely studied, but more information is needed on the dynamics of wind barriers and how they modify the microclimate. Meteorological parameters were measured in the spatial vicinity of slat‐fence windbreaks of 0, 40, and 60% porosity to characterize microclimate modification by windbreaks of various porosities. The highest daytime air temperature, lowest nighttime air temperature, and generally the greatest vertical temperature differences all occurred in the area of lowest windspeed. However, lowest windspeeds occurred at different locations for the different porosity windbreaks. The water‐vapor‐pressure and vapor‐pressure differences between 40 and 5 cm above the crop surface were greatest at 2H leeward of the solid and 40‐percent‐open barriers throughout most of the daylight hours, whereas the vapor pressure at 2H leeward of the 60‐percent‐open barrier was similar to vapor pressure at other leeward positions. The vapor pressure was lower at 12H leeward of all barriers than in the open fieldBowen ratios indicated that evapotranspiration was greater in the sheltered area than in the open, contrary to our earlier findings of less evaporation from evaporimeters leeward of similar barriers. Possible explanations of this anomaly are lower potential evaporation in the shelter, leaving the plants more passive to transpiration, and unaccounted‐for horizontal divergence of sensible and latent heat in the sheltered area.
A Comparison of Ammonium and Nitrate Nitrogen for Cigar Wrapper Tobacco1
Authors: Rhoads F. M. 
Published: July 2010

AbstractFive N fertilizer treatments ranging from all ammonium to all nitrate were applied in a randomized block experimental design, replicated four times, to cigar wrapper tobacco (Nicotiana tabacum L.). The NH4‐N to NO3‐N ratios were as follows 1:0, 3:1, 1:1, 1:3, and 0:1. A nitrification inhibitor was applied to control nitrification of NH4‐N, and black polyethylene mulch was placed on the soil surface to minimize leaching of NO3‐N.The purpose of this experiment was to evaluate plant response of cigar wrapper tobacco to varying ratios of NH4‐N to NO3‐N.Soil samples were taken at monthly intervals and tested for NO3‐N in order to check the effectiveness of the nitrification inhibitor. Yield, quality, and nutrient content of leaves were measured as indexes of plant response.Nitrification appeared to be controlled satisfactorily by the inhibitor 2‐chloro‐6‐(trichloromethyl) pyridine. Cigar wrapper tobacco produced a higher yield and better quality with NO3N than with NH4‐N. Leaf concentrations of N, P, and Mg were affected very little by source of N; however, concentrations of leaf K and Ca increased as applied NO3‐N increased.
Patterns of Water Uptake and Root Distribution of Soybeans (Glycine max.) in the Presence of a Water Table1
Authors: Reicosky D. C. , Millington R. J. , Klute A. , Peters D. B. 
Published: July 2010

AbstractThe increasing importance of water use in crop production has demonstrated the need for integrated studies of water transport phenomena in the soil‐plant‐atmosphere system. A better understanding of the basic principles involved can lead to better management techniques for efficient water use. The purpose of this work was to measure water uptake patterns of soybeans (Glycine max.) and relate these to root distribution and water uptake per unit root length.Water uptake in soil columns was analyzed using the flow equations for water movement in the soil, treating the root system as a macroscopic sink. The sink term represents the volume of water removed by the roots from a known volume of soil per unit time. Two soil columns were analyzed periodically for water content, root weight, and root length. Graphical evaluation of the water content and soil water flux distributions as a function of depth and time permitted determination of the sink term.The results indicated that in the presence of a water table, water uptake was not necessarily related to root distribution and that a small amount of roots near the capillary fringe absorbed most of the water. The results also showed the combined importance and interaction of the hydraulic conductivity and the root distribution in determining the magnitude and the distribution of the sink term. Both of these factors limited the rate of uptake. As the plants grew, both increased water uptake per unit root length and increase in the length of roots contributed to meeting the rising daily rate of water use.
Accumulative Effects of Manure and N on Continuous Corn and Clay Soil. I. Growth, Yield, and Nutrient Uptake of Corn1
Authors: McIntosh J. L. , Varney K. E. 
Published: July 2010

AbstractFour rates of manure and five rates of N were applied yearly in a factorial arrangement to a Panton clay soil (Typic Ochraqualf). Applications of 120 kg/ha of P and 90 kg/ha of K were made each year to all plots. The plots were planted to corn (Zea mays L.). The objectives of the study were to study the effects of continuous corn and manure and N treatments on the physical and chemical properties of the soil and on the growth, yield, and mineral composition of the corn plants over a period of at least 5 years. The results for the latter objective are reported in this paper.During years of normal or less than normal rainfall (1965–67), manure application significantly increased yields of corn grain and stover. Averaged over all treatments of N, plots receiving 66 tons/ha of manure yielded 2.04 tons/ha more than no‐manure plots. This response is especially significant in that basic applications of P and K had been made and starter P used at planting each year. For these years, the first increment of N (56 kg/ha) increased yields on unmanured plots. Higher applications of N reduced yields. Where manure was applied, there was no significant response to N.During relatively wet years (1968–69), manure had beneficial effect on corn growth and yield. The highest, or 66 ton/ha, manure application appeared to be detrimental, particularly where N had been applied. Nitrogen, on the other hand, significantly increased growth rate and yield of corn grain and stover at all levels of manure. For example, plots receiving 224 kg/ha of N yielded 5.51 tons/ha more than no‐N plots.Manure treatments increased percentage K by as much as 0.30% in the corn ear leaves but decreased Ca and Mg. Manure had little effect on percentage N and P. In 1969, a wet year, manure reduced N from 2.72 to 2.44% when averaged over all treatments of N.Chemical analysis of small plants showed the same trends as did analysis of ear leaves. Percentages of AI and Fe were high. But Al varied proportionally to applied N and inversely to manure. For all treatments of N, manure decreased Al from 139 to 85 ppm.Manured plots were slightly but consistently higher in soil moisture. Small differences of about 1% were measured when the soil was near saturation (43% moisture). Differences of 2.5% were measured 1 week later when the soil was near 30% moisture.