bluuebunny/crossref_metadata_2025_split huggingface dataset:
Rates of Net Carbon Dioxide Assimilation in Rice as Influenced by Growth Temperature and Photoperiod1
Authors: Azmi A. R. , Ormrod D. P. 
Published: July 2010

AbstractPlants of ‘Bluebonnet,’ ‘Caloro,’ ‘Dokri,’ and ‘Kangni’ cultivars were grown for 2, 4, 6 and 8 weeks in growth cabinets using temperatures of 35/18, 35/26.5, 35/35 and 40.5/18 C day/night and photoperiods of 8, 10, 12 and 14 hours.The rate of net CO2 assimilation on a leaf blade weight basis was highest at 2 weeks in all varieties at all temperatures and photoperiods and declined with age. The greatest decline at 8 weeks compared to 2 weeks was 71% in Dokri and least was 65% in Bluebonnet. The assimilation rate was consistently higher in plants grown in 8‐hour photoperiod. Compared to 14‐hour, the rate at 8‐hour was higher by 28 and 25% at 6 and 8 weeks, respectively. In most cases, the highest assimilation rates were recorded at 40.5/18 and 35/35 C. Both Bluebonnet and Caloro had higher assimilation rates than Dokri and Kangni.
Boron and Manganese Effects on Protein, Oil Content, and Fatty Acid Composition of Cottonseed1
Authors: Anderson O. E. , Worthington R. E. 
Published: July 2010

AbstractField experiments were conducted to study the effect of Mn and B on the oil and protein content and the fatty acid composition of cotton‐seed produced on soils where supplements of these elements have increased yields of lint cotton. Manganese and B, in separate experiments, were applied to the foliage or to the soil at three growth stages. With only one exception, neither time nor method of applying B or Mn to cotton influenced the oil or protein content, or the distribution of fatty acids within the seed oil. In the single exception, a small but significant increase in oil content occurred when B was applied to the foliage at the 5‐ to 10‐leaf stage. There were negative correlations (P = .01) between seed protein and oil for both Mn and B. Seed oil and protein content varied among locations due to factors other than available soil Mn or B.
Water Stress and Stem Radial Contraction of Cotton Plants (Gossypium hirsutum L.) under Field Conditions1
Authors: Namken L. N. , Bartholic J. F. , Runkles J. R. 
Published: July 2010

AbstractRadial contraction and expansion of cotton plant stems (Gossypium hirsutum L.) were monitored with linear variable displacement transducers throughout the 1969 and 1970 growing seasons under field conditions. Relative water content and water potential measurements of the leaves were routinely made as indices of water stress of the cotton plant for comparison with stem contraction measurements. The amount of stem radial contraction was directly related to the water‐stress indices of the cotton plant. Stem contraction was more sensitive to plant water stress as stress increased. No contraction occurred until relative water contents were below 79 or 83%, depending on stage of plant growth, or until leaf water potentials were lower than −8.0 bars.The relation between relative water content and stem contraction was influenced by stage of plant growth. A higher degree of plant water stress was required to provide an equivalent radial change during the square and early bloom period when vegetative growth rates were high than during the late bloom and boll development period when vegetative growth rates were low. Stage of plant growth did not affect the relation between leaf water potential and radial stem contraction.Leaf water potential recovered more rapidly than cotton stem contraction. However, the relation was well defined for the desorption phase of the stress cycle from minimum stress in early morning (0600 hr) to maximum stress at about 1400 hr.
Effect of Race T of Helminthosporium maydis on Corn Grain Yield1
Authors: Jellum M. D. , Ethredge W. J. 
Published: July 2010

AbstractThe effect of southern corn leaf blight (Helminthosporium maydis) on corn (Zea mays L.) yield as related to dates of planting was determined in 1970 at two locations in Georgia. Estimates of yield loss were based on the relative yields of six susceptible hybrids and one resistant hybrid grown under disease‐free conditions in 1969 and under a severe epiphytotic of southern corn leaf blight in 1970. Yield of susceptible hybrids from the earliest planting date (April 8 and 9) was not reduced by leaf blight in 1970. Yield was reduced by 23% when hybrids were planted on May 8 in the Piedmont region, compared with 46% when planted on May 1 in the Upper Coastal Plain region. A late planting date at each location resulted in an estimated yield loss of 71%.
Growth Patterns of Irrigated Sugarbeet Roots and Tops1
Authors: Johnson Wendell C. , Davis Ronald G. 
Published: July 2010

AbstractElectronic growth sensors were used in the field near Amarillo, Texas, to obtain continuous records on strip chart recorders of the root and top growth of irrigated sugarbeets (Beta vulgaris). The purpose of the study was to characterize the typical diurnal variation in growth rate of the crop and to determine its growth response to variations in ambient atmospheric and soil conditions. The growth sensors were potentiometers, either constructed in the form of slidewire discs or adapted from commercial linear transducers. The root sensors were operated by a pulling action of a noose surrounding the root. The height sensors were rotating slidewire discs attached with fine wires to leaf tips.The growth patterns of sugarbeet roots and tops were very similar with most of the growth occurring at night. The main difference was a decrease in size of roots during the daytime that did not occur with leaves.On a typical day with few clouds in July or August and with the plants under a moderate moisture stress, the growth rate of roots and tops accelerated suddenly about an hour before sunset and reached a peak or maximum point around sunset. Growth continued at a high rate during the night. The growth rate of roots usually reached a secondary peak between midnight and sunrise. The growth rate of roots and tops decreased rapidly after 7 to 8 A.M. and little or no growth took place during the middle of the day. The normal dear−day growth pattern was altered by high moisture stress as well as by cloudiness and rain showers.
Soil Heating Studies with Cool Season Turfgrasses. IV. Energy Requirements for Electric Soil Heating1
Authors: McKiel C. G. , Ledeboer F. B. , Skogley C. R. 
Published: July 2010

AbstractElectrical energy use was recorded for soil heating studies conducted in turf from 1967 to 1969. Heating densities of 54 W/m2 (5W/ft2), 108 W/m2 (10 W/ft2), and 162 W/m2 (15 W/ft2) were employed. Energy consumption was a function of environmental conditions. Regression lines were constructed from kilowatt‐hour and degree‐day data. These data should be useful for estimating energy requirements of similar soil heating installations in turf.
Comparison of Partially Acidulated Rock Phosphate and Concentrated Superphosphate as Sources of Phosphorus for Corn1
Authors: Lutz J. A. 
Published: July 2010

AbstractThe data available measuring the relative efficiencies of acidulated rock phosphate at various levels of applied P are limited, and further investigation of this subject is warranted. Florida rock phosphate was acidulated with H3PO4 at 20 and 100% of that required to convert rock phosphate to concentrated superphosphate. These two materials plus a check (0 P) were applied as treatments for corn (Zea mays L.) during three consecutive years on an acid soil in field experiments. Rates of total P from each source were 0, 10, 20, 30, and 100 kg/ha, which was broadcast and disked in each year just prior to planting.There was an excellent response to P fertilization. Corn yields were similar from both sources of P at some rates of applied P, while at other rates, P from concentrated superphosphate appeared to be the superior source. Phosphorus content of the ear leaves was not affected by P source in 1968, but differences were evident in 1969 and 1970. Leaf K content in 1970 was significantly increased by the highest rate of applied P from both P sources. There was an increase in available soil P only at the highest rates of applied P.At low rates of applied P, CSP was the most economical source of P. At the highest rate of P application, the 20% acidulated rock phosphate appeared to be more economical
Factors Affecting Zinc Absorption by Corn from Volcanic Ash Soils1
Authors: Marinho M. L. , Igue K. 
Published: July 2010

AbstractIn high P‐fixing soils, such as volcanic ash soils and tropical oxisols, the need for heavy P application may be of consequence in the absorption of Zn. The objectives of this study were to determine the availability of native and applied Zn in three soils considered deficient, to determine the effect of P application and the level of free R2O3 in the soil on Zn absorption, and to correlate Zn absorption with soil tests.The amount of Zn extracted with 0.01 M Na2‐EDTA and 0.1 N HC1 increased with Zn applications and decreased as the free R2O3 content increased. P applications increased the amount of Zn extracted by the EDTA method, but did not show any definite trend in the case of the HC1 method, although higher amounts of Zn are extracted by the latter.The total amount of Zn absorbed by the corn (Zea mays L.) plant increased with Zn application and decreased as the free R2O3 present in the soil increased. The effect of P was not statistically significant. However, Zn concentration in the tissue decreased as the free R2O3 content and applied P increased. The L value also increased with Zn application, but P application had no definite effect on it. Higher correlation coefficients between Zn absorption and soil‐extracted Zn were obtained from the EDTA method as compared to the HC1 method. The EDTA method also correlated better with the L value than with the HC1 method.
Environmental Factors Affecting Root Development and Reserve Carbohydrates of Bermudagrass Cuttings1
Authors: Burns Robert E. 
Published: July 2010

AbstractBermudagrass (Cynodon sp.) cuttings were grown in growth chambers to determine the effect of temperature, light intensity, and daylength on root development. Total root length, average length of root, number of roots, and roots per node were less when grown under lower temperature, (27/15 C vs. 32/24 C), light intensity (800fc vs. l,500fc), or daylength (10 hr vs. 16 hr). Root branching was 67% less at the low temperature, 42% less in low light intensity, but was not affected by daylength. Reserve carbohydrates were less with short daylength or low light intensity, but were higher under low temperature. The number of cuttings that produced no roots, those on which new shoots developed, and the number of nodes producing roots varied independently of temperature, daylength, or light intensity. Light intensity and temperature appear to be as important as daylength in the performance of late‐sprigged bermudagrass.
Sensitivity of Southern Peas to Plant Water Deficit at Three Growth Stages1
Authors: Hiler E. A. , van Babel C. H. M. , Hossain, M. M. , Jordan W. R. 
Published: July 2010

AbstractResponse of southern peas (Vigna sinensis L. Endl. var. Burgundy) to different levels of water deficit at three different stages of growth was measured in a greenhouse. In each stage, plants were stressed to three levels of leaf water potential: — 14 bars, — 21 bars, and —28 bars. Crop susceptibility factors (fractional reductions in yield compared to a nonstressed treatment) were determined for each stage of growth and level of plant water deficit. The flowering period was found to be the most sensitive stage, regardless of deficit level. The pod development stage was found to be least sensitive to level of deficit. A water deficit of — 28 bars, however, caused a yield reduction of greater than 50% for all growth stages. Stress‐day index values were calculated and related to crop yield. The use of the stress‐day index concept in irrigation scheduling is discussed. Leaf water potential varied linearly with soil water potential between 0 and — 15 bars. Leaf diffusion resistance became high and transpiration was negligible after the leaf water potential reached — 10 to — 12 bars; the corresponding soil water potential was — 5 bars. Water‐use efficiencies were highest for the nonstressed treatment and the treatment with the low deficit level during the first stage.
Effects of Increasing Amounts of Organic Residues on Continuous Corn: II. Organic Carbon, Nitrogen, Phosphorus, and Sulfur1
Authors: Larson W. E. , Clapp C. E. , Pierre W. H. , Morachan Y. B. 
Published: July 2010

AbstractWith the advent of well‐fertilized corn (Zea mays L.) raonocultures with large amounts of residues returned to the soil, the question arose as to whether organic matter could be maintained at satisfactory levels in Corn Belt soils. To answer this question changes in the amounts and composition of the soil organic matter were determined in a field experiment where different types [alfalfa (Medicago sativa L.), cornstalks, sawdust, oat straw (Avena sativa L.), and bromegras(Bromus inermis Leyss)] and amounts (from 0 to 16 tons/ha/yr) plant residues were added to Marshall silty clay loam (Typic Hapludoll) for 11 consecutive years. The soil was cropped to corn and large amounts of N fertilizer were added. Organic C, N, S, and P contents of the soils increased in proportion to the amount of plant residues added. After 11 years contents of the 0‐ to 15‐cm depth of the check plots were 1.6% C, 0.15% N, 0.023% S, and 0.018% P. Average increases over the check for C, N, S, and P were 47, 37, 45, and 14%, respectively, for the 16‐ tons/ha/yr treatment. Type of plant residue when added at 8 tons/ha/yr did not influence the C or P contents of the soils differently. The organic N and S contents, however, were lower with sawdust than with the other residues. Cumulative effects of increasing quantities of organic residues on available nutrients in the soils showed that NH4‐N production, weak‐acid‐soluble P, and exchangeable K increased significantly. The amount of cornstalk residue needed to prevent loss of organic C was estimated to be 6 t/ha/yr.
Digestion of Fresh Forage in Rumen Fluid1
Authors: Monson Warren G. , Powell Jerrel B. , Burton Glenn W. 
Published: July 2010

AbstractThis technique to evaluate digestion of fresh forage was developed as an additional tool for our forage breeding and evaluation programs. Leaf discs or segments were incubated in rumen fluid to assess the rate and progression of digestion of fresh forage samples. Digestion occurred at cut or broken surfaces as the cuticle formed a barrier to entry of rumen microflora. Differences in rate of digestion between species and between lines within a species were clearly apparent.
Effects of Variety, Seeding Rate, Companion Species, and Cutting Schedule on Crownvetch Yield1
Authors: Mays D. A. , Evans E. M. 
Published: July 2010

AbstractCrownvetch (Coronilla varia L.) has previously been used for erosion control at several southern locations, but little or nothing was known of its productivity under intensive management or its competitive ability in mixtures with grasses of the region. At present seed prices the recommended seeding rate of 20 kg/ha or more would make establishment costs prohibitive.With the increasing interest in crownvetch as a forage, it was necessary to learn whether it is adapted for intensive management in the South either alone or in mixtures and to show that establishment costs could be reduced by use of lower seeding rates.‘Penngift,’ ‘Chemung,’ and ‘Emerald’ varieties of crownvetch were seeded at Muscle Shoals, Ala., at rates of 5.6, 11.2, and 22.4 kg/ha in pure stands. At the same time, Penngift was seeded at 2.8, 5.6, and 11.2 kg/ha with orchardgrass (Dactylis glomerata L.), tall fescue (Festuca elatior), and alfalfa (Medicago sativa L.)Data from the pure stands indicated that there were no significant yield differences attributable to variety or seeding rate over a 2‐year period. New treatments were then assigned and the three varieties were subjected to two, three, or four cuttings annually. Four cuttings resulted in significantly less forage yield than two or three cuttings and caused severe stand loss after 2 years.The presence of alfalfa in the seeding mixture depressed crownvetch establishment and long‐term yields. Mixtures with fescue or orchardgrass produced more total forage than crownvetch alone in 2 out of 4 years. A good legume‐grass mixture was maintained for 3 years, but there were severe crownvetch stand losses by the 4th year.It was concluded that crownvetch is not adapted for intensive use as a forage plant in the South, although it seems well adapted for use as an infrequently cut ground cover.
Effect of Nitrogen Source on Corn and Bromegrass Production, Soil pH, and Inorganic Soil Nitrogen1
Authors: Power J. F. , Alessi J. , Reichman G. A. , Grunes D. L. 
Published: July 2010

AbstractLittle information is presently available on the effects of N source on dryland crop production in the Northern Plains. Therefore a field experiment was conducted for 4 years to assess the relative merits of ammonium sulfate, ammonium nitrate, calcium nitrate, and urea applied annually at 55 and 110 kg N/ha to both corn (Zea mays, L.) and bromegrass (Bromus inermis, L.) grown on a fine sandy loam (pachic haploboroll) with surface pH of 6.5 and no free carbonates. Plants were harvested at maturity and soils were periodically sampled for water content, inorganic N content, and pH. Corn production was highest for ammonium sulfate and ammonium nitrate at 110 kg N/ha. Leaf tissue at silking from all fertilized corn contained over 2.8% total N. Soil inorganic N accumulating during the first 3 years under corn was leached below the root zone by 514 mm of precipitation during the fourth growing season. At the 110‐kg N rate, bromegrass production was lowest with urea, possibly because of ammonia volatilization. Nitrate sources of N greatly enhanced early season growth of bromegrass. All fertilizer N applied was immobilized in the bromegrass ecosystem, prohibiting any carryover or leaching of soil nitrate. Soil pH changes due to fertilization were not reflected in plant growth.
Response of Tifway Bermudagrass to Sulfur on Sandy Soils1
Authors: Volk G. M. , Horn G. C. 
Published: July 2010

AbstractIt was the purpose of this investigation to determine if previously reported differential growth and color response of Tifway bermudagrass (Cynodon dactylon L. Pers.) on a loamy fine sand to various N and K sources in field plot tests correlated with S applied in these materials and S percentages in the grass. The growth response to (NH4)2SO4 over NH4NO3 correlated positively with S percentage increase in the grass. Subblock treatments of K sources within the 2 N sources showed a growth response and S percentage increase in the grass in increasing order for K2SO4, KCl, SuL‐po‐mag, and K2CO3, which did not follow the S applied as a component of the K source. Retention of applied SO4‐‐ by the mineral subsoil was negligible, but increase in total S in the surface soil probably was the result of build‐up of organic S during a 4‐ year period. There was no differential effect of NH4 + vs. NO3 on the uptake of S at the average N/S ratio of 12.5 and average S percentage of 0.35 in the grass. It is suggested that sulfate‐S application be coordinated with N application frequency on sandy soils.
Water Potentials in Nonwilted Dianthus Grown in Different Nutrient Solution Concentrations1
Authors: Schekel Kurt A. , Hanan Joe J. 
Published: July 2010

AbstractExperiments were undertaken to determine if Dianthus caryophyllus L. adjusted its internal osmotic potential downward with decreasing solution potential and the concomitant effects on water and turgor potentials. Plants were grown in a gravel substrate, irrigated two to four times daily with solutions of varying potentials, and measurements were made from before sunrise to noon or shortly thereafter on clear days. Plant osmotic potentials adjusted to increase the potential gradient between solution and plant with decreasing solution potential. There were no observable differences between treatments with respect to stomatal aperture or leaf diffusion resistance. The xylem hydrostatic pressure decreased to a greater extent in plants grown in —1.0 bar solutions than in those grow in −0.3 bar solutions as atmospheric evaporative demand increased. Polynomial regressions of potential on evaporative demand had calculated correlations exceeding 0.90. Differentiation to determine the rate of hydrostatic potential change with change in evaporative demand showed the rate to be highest at low evaporative demands in plants grown in −1.0 bar solutions, gradually decreasing to 0 at high vapor pressure differences near 16 mm Hg. Carnations in −0.3 bar solutions had rates approaching O at low and high atmospheric demands, with a definite maximum near 9 to 10 mm Hg. The differences between hydrostatic potential and plant osmotic potential, ignoring matric and xylem potentials, showed carnations in −1.0 bar solutions to have consistently lower turgor potentials than plants grown in less concentrated solutions.
Response of Rice Plants Grown in Three Potted Luzon Soils to Additions of Boron, Sulfur, and Zinc1
Authors: Lockard R. G. , Ballaux J. C. , Liongson Emma A. 
Published: July 2010

AbstractThree low‐yielding Luzon soils, Quingua clay loam, Bantog loam, and Umingan loam, on which plants did not respond sufficiently to N, P, or K, were tested in pot studies with three levels of B, S, and Zn in a 34 factorial design to show the response on the yield and nutrient content of rice (Oryza sativa L.).None of the soils was deficient in B, as additions of B resulted in decreased yield and the development of foliar symptoms resembling those of B toxicity. Plants in two soils responded to the addition of S; those in Quingua clay loam gave a greater response than those in Bantog loam. Addition of Zn did not increase the yield of plants in any of the three soils. However, young plants growing in Umingan loam exhibited symptoms resembling those of Zn deficiency in treatment Zn0.The level of each nutrient in the straw was increased by the addition of that nutrient to the soil. The most pronounced effect was on the S level in the plant when S was applied to the soil. The linear or quadratic equation to calculate this relationship is presented for each nutrient.The highest level of B applied to the soil, treatment B2, significantly increased the level of S in the straw compared to treatment B0 but it did not increase yield.
Effect of Moisture Stress at Different Stages of Growth: II. Cytoplasmic Male‐sterile Corn1
Authors: Vincent G. B. , Woolley L. G. 
Published: July 2010

AbstractThe purpose of this study was to determine if the greater stress‐tolerance of corn plants with male‐sterile cytoplasm was due to their ability to extract, more moisture from the soil and retain it against atmospheric demand. If this is true, it would have significant impact on the water management and adaptation of the corn (Zea mays L.) plant.An experiment was conducted on Colo silt loam soil in 1967 at Ames, Iowa to compare the effects of moisture stress at different stages of growth on Texas male‐sterile cytoplasm (cms) corn hybrids and their normal cytoplasm counterparts.Grain yields were reduced significantly by a moisture stress imposed at anthesis. Hybrids with cms did not yield differently from their counterparts with normal cytoplasm, but cms hybrids maintained a higher level of leaf turgor when exposed to moisture stress at anthesis. The method used to establish equally severe intensities of stress was the withholding of irrigation water until a minimum level of 75% leaf turgidity was reached. Hybrids with normal cytoplasm withstood 1 day of serious stress during a 3‐day period, while hybrids with cms withstood 3 days of serious stress during a 10‐day period before reaching the minimum leaf turgidity.