bluuebunny/crossref_metadata_2025_split huggingface dataset:
Influence of Silt and Clay on the Physical Performance of Sand‐Soil Mixtures
Authors: Whitmyer R. W. , Blake G. R. 
Published: July 2010

AbstractSmall variations in component characteristics of materials used for soil mixtures for landscaped areas, such as sportsfields, sometimes result in unpredictable performance. The objective of this research was to determine the effect of variation in the relative amounts of silt and clay in soil mixtures having high sand content on soil physical properties of importance to mixture performance. Soil mixtures having sand contents ranging from 80 to 92% by weight and silt/clay ratios varying from 0.2 to 4.8 were formulated using seven soils. For 28 mixture combinations, determinations were made for shear strength, air‐filled porosity, saturated hydraulic conductivity, and hydraulic diffusivity. The extent and texture of particles migrating during saturated water flow were also determined. Sand content was the primary variable determining physical properties of the soil mixtures, the magnitude of measured differences being greater for variations in sand content compared to variations in the silt/clay ratio. Variations in the mixture silt/clay ratio did however result in significant differences in properties. As the silt/clay ratio increased from 0.2 to 4.8 in a soil sample having a sand content of 88%, shear strength decreased from 34 to 20 kPa (at a normal stress of 36 kPa), and air‐filled porosity increased from 12 to 24 m3/100 m3 (at a water potential of −2.9kPa). Saturated hydraulic conductivities and the volume of migrating particles increased as the silt/clay ratio increased at a given sand content.
Spring Establishment of Turf‐Type Tall Fescue Seed Crops with Cereal Companion Crops
Authors: Chastain T. G. , Grabe D. F. 
Published: July 2010

AbstractSpring plantings of tall fescue (Festuca arundinacea Schreb.) for seed production are common in the Pacific Northwest, but seed yields are negligible in the year of planting. Planting tall fescue seed crops with cereal companion crops could increase the profitability of seed production. The purpose of this study was to determine the competitive effects of spring cereals on growth, seed yield, and economic return of turf‐type tall fescue. ‘Bonanza’ tall fescue was interplanted iin 45‐cm rows with ‘Waverly’ spring wheat (Triticum aestivum L.), ‘Steptoe’ spring barley (Hordeum vulgare L.), and ‘Cayuse’ spring oats [Avena fatua var. sativa (L.) Haussk.] in 15‐ and 30‐cm rows. Experiments were initiated in March 1985 near Corvallis, OR, and repeated in 1986. Cereals reduced the photosynthetic photon flux density (PPFD) available for tall fescue seedlings, which caused transient increases in chlorophyll content and reduced soil temperature by 1.8 °C. Soil water content was decreased by competition from cereals, causing greater stomatal resistance and lower transpiration rate. Reduction in PPFD and soil water by cereals was responsible for low tall fescue tiller and dry matter production. Following cereal harvest, tall fescue regrowth and new tiller initiation were delayed until spring as a consequence of competition with cereals, resulting in fewer fertile tillers and a 61% reduction in firstyear (after planting) seed yield compared with no companion crop. Tall fescue growth and seed yield were similar with all cereals, row spacings, and combinations of row spacings and cereals. Second‐year (after planting) seed yield was 15% greater when fescue was established with cereals than when no companion crop was used. Dry conditions caused low grain yield and increased competition by cereals, and was partly responsible for poor economic returns; however, fescue planted with spring oats earned $139.00 ha‐1 more than monoculture over a 3‐yr period because of compensatory increases in second‐year seed yield. This suggests that turf‐type tall fescue establishment with cereals could be more profitable in spring with irrigation or in fall when water is not limiting.
Nitrogen Economy and Canopy Carbon Dioxide Assimilation of Tropical Lowland Rice
Authors: Schnier H. F. , Dingkuhn M. , De Datta S. K. , Mengel K. , Wijangco E. , Javellana C. 
Published: July 2010

AbstractIncreased irrigated areas, availability of short‐duration modern rices (Oryza sativa L.) and herbicides, and increasing labor cost have motivated Asian farmers to shift from transplanting to direct seeding of lowland rice. Information on cultural requirements of direct seeded lowland rice in Asia is limited. Thus, two field experiments were conducted during the dry season on a Vertic Tropaquept soil to evaluate various cultural practices of direct seeded rice, and to compare the growth characteristics of direct seeded and transplanted rice. Direct seeding increased vegetative growth and shortened crop duration by more than 1 wk. Broadcast seeded rice gave the highest tiller number, followed by row seeded and hill‐wise dibbled rice. Relative tillering rate was significantly correlated with relative growth rate. Greater vegetative growth of direct seeded rice decreased tissue N concentration which in turn impeded sink formation. Grain yield of direct seeded rice was significantly correlated with spikelet number per panicle but not with panicle density, while the reverse trend was observed in transplanted rice. Band placement of fertilizer N gave significantly higher canopy CO2 assimilation rates and grain yield than did conventional fertilizer application methods in both direct seeded and transplanted rice. By increasing N availability to the plant, band placement allowed the use of a one‐third to two‐thirds N split application which increased plant N concentration during the reproductive stage, particularly in direct seeded rice. Leaf area index (LAI) was higher in direct seeded than in transplanted rice. Canopy photosynthesis was limited by LAI during the vegetative growth stage and by foliage N concentration during the reproductive stage.
Evaluating a Model for Predicting Nutrient Uptake by Rice During Vegetative Growth
Authors: Teo Y. H. , Beyrouty C. A. , Gbur E. E. 
Published: July 2010

AbstractSince submerged soils create a unique chemical environment from which roots take nutrients, models that estimate nutrient uptake for upland crops may differ from those for rice (Oryza sativa L.). A mathematical model that had been used to predict nutrient uptake by corn (Zea mays L.), soybean [Glycine max. (L.) Merr.], and sorghum (Sorghum bicolor L.) was evaluated for predicting uptake by rice under flooded soil conditions. Our objectives were to evaluate such a model for rice and to conduct greenhouse and growth chamber studies to measure the soil and plant parameters required by the model. Sensitivity analyses were also conducted to determine the parameter most influencing N, P, and K uptake. Two soils (Crowley silt loam (Typic Albaqualfs) and Calhoun silt loam (Typic Glossaqualfs)] and three rice cultivars (Lemont, Katy, and Mars) were selected for this study. Linear regression of predicted vs. observed uptake for N, P, and K gave satisfactory fits to the data with R2 values of 0.48, 0.99, and 0.88, respectively. The slopes of the lines for predicted vs. observed uptake for N and K were 1.01 and 0.94, respectively, and the relationships did not depend upon either soil or cultivar. However, the prediction of P did depend on cultivar. The slopes of the lines for predicted vs. observed P uptake by Mars, Lemont, and Katy were 1.81, 1.08, and 1.02, respectively. The parameters most affecting N uptake were root growth rate, N concentration in the soil solution, and the half‐distance between root axes. However, parameters most influencing P and K uptake were root growth rate, root radius, and maximal influx rate.
Developing Guidelines for Replanting Grain Sorghum: III. Using a Plant Growth Model to Determine Replanting Options
Authors: Heiniger Ronnie W. , Vanderlip Richard L. , Williams Jeffrey R. , Welch Stephen M. 
Published: July 2010

AbstractThe adaptability of grain sorghum [Sorghum bicolor (L.) Moench] complicates decision making regarding the replacement of damaged stands. Our objective was to construct replanting guidelines for a broad range of situations by using a sorghum growth model to project yields for both original and replanted stands. Sorghum yields were simulated for 33 seasons for every combination of seven planting dates, six plant populations, and three hybrid maturity classes at three Kansas sites representative of Midwest sorghum producing areas. The outputs were tabulated to obtain yield distributions for both original and replanted crops. Net returns for replanting were calculated from yield differences, input costs, and harvest prices. Increases in both mean yields and net returns were associated with greater variability. The choices of replant timing, hybrid maturity, and planting density therefore depend on the grower's risk preferences. In western Kansas, an area with soils and climate representative of most of the Great Plains, risk‐neutral producers should replant with an early‐maturity hybrid at 50 000 plants ha−1 if the original population declines to less than 20 000 plants ha−1. In eastern Kansas, an area representing western Corn Belt sorghum production, replanting with a medium‐maturity hybrid at 200 000 plants ha−1 is a good option when a medium‐ or late‐maturity hybrid falls below 20 000 plants ha−1 or an early hybrid drops beneath 100 000 plants ha−1.
Germination of Vicia Species and Interspecific Lines as Affected by Temperature Cycles1
Authors: Elkins D. M. , Hoveland C. S. , Donnelly E. D. 
Published: July 2010

Temperature cycles of 4.5–21, 21–4.5, 21–32, and 32–21 C were used in germinating scarified and unscarlfied seed of vetch species and advanced generation interspecific hybrids.The initial temperature of a cycle had marked effects on both the rate and final germination percentage of certain entries. Variation in response to temperature cycles was found between Vicia species and within V. sativa and V. angustifolia. Scarified seed of parents of the interspecific hybrids differed greatly; the V. sativa parent (Ala. 1894) germinated faster at high temperatures, whereas the V. angustifolia parent (P.I. 121275) germinated faster at low temperatures. The behavior of interspecific hybrid progeny indicated a recombination of genes that conditioned the physiological requirements for germination. Unscarified seed of V. grandiflora and an interspecific hybrid germinated more rapidly at low temperatures. Unscarified seed of another hard‐seeded species, V. angustifolia, responded in a reverse manner, germinating more rapidly at high temperatures. Germination response to temperature was found to be controlled by hard seedcoat in addition to a physiological response of the embryo.
Interception of Solar Radiation and Dry Matter Production by Various Soybean Planting Patterns1
Authors: Shibles R. M. , Weber C. R. 
Published: July 2010

Solar radiation interception and dry matter production were studied in soybeans (Glycine max (L.) Merr.) grown in various planting patterns (4 populations of 26, 52, 104, and 209 thousand plants per acre within each of 4 row widths – 5, 10, 20, and 40 inches).Increased population resulted in increased leaf area index (LAI) and a reduction in the number of days from emergance to 95% (daily basis) solar radiation interception (D95). At corresponding populations of 52,000 or above, D95 was considerably higher for the 40‐inch row pattern than for the other spatial arrangements, which differed in reaching D95 by only a few days.Dry matter production was a functin of percent solar radiation interception regardless of planting pattern. However, the efficiency of utilization of intercepted energy differed between years for the mean of all treatments, and was significantly lower for the 208,000 plant population in 1962. These differences were attributed to a limitation imposed by moisture stress.Seed yield was not correlated with total dry matter produced, dry matter produced during seed formation, or solar radiation intercepted. As determined by differences in harvest index, seed yield was a function of differential utilization of photosynthate between vegetative and seed production. In general, high population or close plant spacing in any one direction tended to result in a low harvest index. Thus, while full interception during seed formation is required for maximum seed yield, conditions resulting in a high seasonal interception may not result in highest seed yield.
Quantitative Presentation of the Systematic Relationships Among Twenty‐one Sorghum Species1
Authors: Liang George H. L. , Casady A. J. 
Published: July 2010

Twenty‐one species in the subsection ArundinaceaS nowden, subgenus Eu‐Sorghum Stapf, genus Sorghum Moench, were studied to obtain the pattern of interspecific variation. A statisical taxonomic method which employs numerous but unweigbted characters was used to derive the quantitative index of affinity between any two species. The indices of association then were exploited in establishment of a diagram suggestive of phylogenetic relationships.A tree‐like diagram was constructed from between species correlations and the resultant correlation matrices. The diagram shows the interspecific relationship amongth e species studied, and indicates that the species may be divided into three series consisting of 14, 6, and 1 species, respectively.
Tillering and Carbohydrate Contents of Orchardgrass as Influenced by Environmental Factors1
Authors: Auda Hamid , Blaser R. E. , Brown R. H. 
Published: July 2010

Three experiments were conducted in the greenhouse and environment chambers to study effects of nitrogen rates, light intensity, daylength, temperature, and defoliation, and their interrelationships on tillering, growth, and water‐soluble carbohydrates in orchardgrass. Tillering, growth, and carbohydrates increased as light intensity was increased from 25% to normal sunlight. Tillering was associated with light energy rather than photoperiod. Extending the photoperiod with low light intensity reduced tillering, but not carbohydrates.Tillering and growth was low at 50 to 60 F as compared with 70 to 80 F night‐day temperatures; carbohydrates were much higher for the lower temperature, this was attributed to rapid carbohydrate utilization at the higher temperature.Tillering and plant weights increased as defoliation was relaxed. Such improved tillering was attributed to more carbohydrates in stubble bases where new tillers formed. Root growth trends were similar to those for tillering.Nitrogen stimulated tillering and growth, which lowered carbohydrates. Root weights decreased with added nitrogen.The single order interactions of the factors mentioned above on tillering and carbohydrates were generally significant. High tillering appeared to be associated with factors that have potentially high photosynthesis and carbohydrate storage, but environmental factors must also favor rapid growth and utilization of carbohydrates in a dynamic biological system.
Estimating Harvest Date of Corn in the Field1
Authors: Schmidt J. L. , Hallauer Arnel R. 
Published: July 2010

Moisture data for 12 years from the period 1940 to 1963 were summarized to determine the relation between kernel moisture and time. The rate of kernel moisture reduction was determined for five arbitrary moisture phases and used to predict when specified moisture levels would be attained from pollination date. Correlation studies were made between rate of kernel moisture reduction and four weather factors (air temperature, saturation deficit, wet bulb depression, and relative humidity).The average daily rates of kernel moisture reduction varied considerably from year to year within the five phases of corn growth. Above 30% kernel moisture content the rate of moisture reduction was significantly related to the temperature of the air. Below 30% kernel moisture the reduction rate was significantly related to saturation deficit, wet bulb depression, and relative humidity of the air.A curve, along with a 95% confidence band, was constructed to show the average number of days for corn to go from pollination to a given kernel moisture.
Carbohydrates in Grasses. I. Sugar and Fructosan Composition of the Stem Bases of Several Northern‐Adapted Grasses at Seed Maturity1
Authors: Smith Dale , Grotelueschen R. D. 
Published: July 2010

Extraction of the stem base tissue of timothy, orchardgrass, and redtop at near seed maturity with concentrations of ethanol from 95 to 0% yielded steadily increasing percentages of carbohydrates, indicating a series of fructosans of increasing chain length. Reed canarygrass and Kentucky bluegrass tissue also yielded increasing percentages, but not continuously so. Fructosans in all of the above species were predominantly of long‐chain length. Bromegrass,t all rescue, ryegrass, and quackgrass tissue yielded no additional carbohydrate at low ethanol concentrations, indicating that the fructosans present were relatively short‐chain polymers.Concentration of the ethanol must be considered in separating free sugars from low molecular weight fructosans, or otherwise some of the fructosans may De extracted along with the sugars. Thin layer chromatography showed that 85% ethanol was the most suitable concentration with which to extract the free sugars from the fructosans in those species containing predominantly long‐chain fructosans. With the species containing predominantly short‐chain fructosans, 90% ethanol was most suitable. More dilute ethanol solutions extracted short‐chain fructose polymers along with the glucose, fructose, and sucrose.Glucose, fructose, and sucrose constituted only a small part of the total water‐soluble carbohydrates in all of the grass species. Fructosans were the predominant carbohydrates.
Directed Effects of Environment on Populations of Small Grain Varieties1
Authors: Grafius J. E. 
Published: July 2010

Evidence was presented that the effect of environmental stress on a population of oat (Avena sativa L.) and barley (Hordeum vulgate L.) varieties is directed. if random subsets are drawn from a population, then it is expected that the subsets will respond to stress in a similar manner.I t appears, on the basis of limited evidence, that nonrandom subsets will also respond to stress in a similar way, providing the various subsets are not too divergent. Just how great a divergence is permitted before the subsets react differently can probably only be determined by tests. In the case of oats, varieties from Europe, Canada, and northern USA, and from the Corn Belt reacted in a similar manner, indicating a directed effect of environmenot n the subsets.Subsets drawn from a barley population in a nonrandom manner showed diverse reaction in the case of a split into 6‐row and 2‐row groups. But when a nonrandom split of the 2‐row group into an early and late subset was made, fair agreement between the subsets in their response to environmental change was observed for several traits.If a directed impact of environment on moderately divergent subsets, such as the change in breeding populations over a period of time, can be demonstrated it will be a means of establishing meaningful genetic correlations. These correlations would be a measure of constancy of a trait at a location over a period of years and would be of use in selection and prediction. It is expected that the hypothesis will apply more to polygenic traits than to traits such as rust resistance.
Observed and Expected Response in Four Selection Experiments in Maize1
Authors: Moll R. H. , Robinson H. F. 
Published: July 2010

Full‐sib family selection is being conducted in three populations of maize; viz. a hybrid population derived from a cross of inbred lines and two populations which are open‐pollinated varieties. Reciprocal recurrent selection is being conducted in the crossbred of the varieties. The results of the first several cycles of selection are compared with expectations based on estimates of variances.There is good agreement between observed and expected selection response of the primary trait, yield, in three of the four experiments. Number of ears per plant showed a reasonably consistent increase associated with selection for high yield. Correlated responses of two other traits, ear height and days to tassel, were less consistent and generally in poor agreement with expectation.Reciprocal recurrent selection for crossbred performance and full‐sib family selection for purebred performance were compared in their effectiveness for improving both purebred and crossbred performance. After 3 cycles of selection, it appears that full‐sib family selection was at least as effective as reciprocal recurrent selection in improving crossbred performance.
Inheritance of Plant Height, Yield of Grain, and Other Plant and Seed Characteristics in A Cross of Hard Red Winter Wheat, Triticum aestivum L.1
Authors: Johnson V. A. , Biever K. J. , Haunold A. , Schmidt J. W. 
Published: July 2010

The inheritance mechanisms of seven plant and seed characters were studied in the F1, backcrosses and segregating generations from the cross of two winter wheat varieties differing in plant height and other characteristics.Evidence for the control of plant height by three major gene pairs was obtained. Additive gene action accounted for most of the plant height variance. Maturity was controlled by a single dominant gene pair for earliness. A bimodal F2 frequency distribution for kernel weight indicated operation of a relatively few genes. Heterosis for high yield was evident. The 4380‐pounds‐per‐acre yield of the F1 exceeded the most productive parent by 12.9%. Heavy kernel weight and, to a lesser extent, number of spikes per plant contributed to the high yield of the F1. The genetic expression of spike length and number of rachis internodes was completely additive.Heritability percentages for plant height, spike length, maturity, and kernel weight were sufficiently high to indicate that selection in the F2 for these traits could be effective. Selection for number of rachis internodes, number of tillers, or grain yield would be ineffective. Plant height was significantly correlated with kernel weight, spike length, maturity, grain yield, number of spikes per plant, and number of rachis internodes.
Outcrossing of Oat Plants (Avena sativa L.) Grown from Mutagen‐Treated Seeds1
Authors: Grindeland R. L. , Frohberg R. C. 
Published: July 2010

The percent of outcrossing on oat plants from untreated and mutagen‐treated seeds was determined from four experiments. The mutagens used were thermal neutrons and ethyl methanesulfonate.The year‐to‐year percent outcrossing varied from 2.4 to 6.0 in the mutagen‐treated populations and 0.5 to 2.4 in the checks. The mean outcrossing percents for all experiments were 4.0 and 1.4, in the mutagen‐derived and check populations, respectively. Both mutagens, when applied in proper dosages, were equally effective in causing outcrossing.
Production of F1 Seed in Castorbeans by Use of Sex Genes Sensitive to Environment1
Authors: Zimmerman L. H. , Smith J. D. 
Published: July 2010

By growing castorbeans, Ricinus communis L., in different environments, genotypes were obtained with both the N‐pistillate gene ƒ for female racemes and environmentally sensitive genes for interspersed‐staminate flowers. These genotypes were homozygous for the ƒ gene, but not always for the genes for interspersed‐staminate flowers. With penetrance of the genes for interspersed‐staminate flowers at a location having high summer te~nperatures, a July average of 91 F, plants were propagated by selfing or sibbing. With nonpenetrance at locations having lower summer temperatures, July averages of 75 to 83 F, F1 hybrid seed was produced without roguing. Previous methods using the ƒ gene required roguing monoecious plants from the female parent, often involving more than 50% of the plants.In test crosses, presence of interspersed‐staminate flowers was recessive to absence. There was wide variation among genotypes tested for frequency of interspersed‐staminate flowers, suggesting a polygenic system with considerable opportunity for selection.