bluuebunny/crossref_metadata_2025_split huggingface dataset:
Tall Fescue Yield, Tillering, and Invaders as Related to Management1
Authors: Dobson James W. , Beaty E. R. , Fisher C. D. 
Published: July 2010

AbstractTall fescue (Festuca arundinacea Schreb.) is widely grown as a winter perennial forage in the upper South. It is primarily used for cool‐season grazing by cattle producers, and improved digestibility and increased fall and winter forage production would be useful. A field experiment was conducted for 3 years on a tall fescue sod growing on a member of fine loamy mixed family of Cumulic Haplumbrepts to establish the effect of four clipping schedules, 5‐ and 10‐cm clipping heights and 56‐ and 224‐kg/ha N‐rates on dry forage yields, tiller numbers, and percent invaders.Forage yields varied from slightly more than 3,600 kg/ha when fertilized with 56 kg/ha of N and clipped at a height of 10 cm to more than 8,820 kg/ha when fertilized with 224 kg/ha N and clipped at 5 cm. Reducing the clipping height from 10 to 5 cm increased average forage yield from 5,512 to 6,735 kg/ha or 22%. Increasing N fertilization from 56 to 224 kg/ha doubled dry forage production from 4,137 to 8,111 kg/ha. Tillers/unit area were highest at the 5‐cm clipping height, 224 kg/ha rate, and frequent clipping schedule. Lowest numbers of tillers/area were obtained on plots clipped at 10 cm, fertilized with 56 kg/ha N, and clipped infrequently.Invaders were limited almost exclusively to plots clipped at a height of 5 cm where 56 kg/ha N was applied. Very few invaders were present on plots clipped at 10 cm. More invaders were present on 56‐kg/ha N plots than on 224‐kg/ha N plots.Tall fescue responded to management treatments applied. However, it is probable that new treatments can be developed that will more uniformly distribute forage production through the season, facilitate the introduction of invaders (clovers), and stabilize tillers/area for increased fall and winter growth and improve forage quality (digestibility). These additions would add appreciably to the value of tall fescue as a forage crop in the Southeast.
Seedling Emergence as Related to Temperature and Moisture Tension1
Authors: Wright D. L. , Blaser R. E. , Woodruff J. M. 
Published: July 2010

AbstractMixtures of seed that provide quick germination and seedling growth during most seasons are important for controlling erosion and establishing an aesthetically pleasing turf in highway corridors. To aid in selection of species for mixtures, we designed an experiment to determine total emergence and rates of emergence of several grass and legume species and cultivars under various soils moisture and temperature regimes. Rates of seedling emergence for 12 grass and legume species or cultivars were determined in the laboratory on a Groseclose (clayey, mixed, mesic, Typic, Hapludult) subsoil maintained at soil water potentials of −1/3, −3, −6, and −9 bars and at 21 and 28 C over a 19‐day period. Abruzzi rye (Secale cereale L), German millet (Setaria italica L.), perennial and annual ryegrasses (Lolium perenne L. and L. multiflorum Lam), weeping lovegrass (Eragrostis curvula Schrad. Nees), and redtop (Agrostis alba L.) were considered aggressive species. After 4 days at −1/3 bar of soil water potential, seedling emergence for these species ranged from 54 to 100% emergence and by day 6 total emergence was the highest for all groups at either temperature. Intermediate species included creeping red rescue (Festuca rubra L.) Kentucky bluegrass (Poa pratensis L.), Kentucky 31 tall fescue (Festuca arundinacea Schreb.), crownvetch (Coronilla varia L.) at 21 C, and common bermudagrass (Cynodon dactylon L.) at 28 C. Emergence at 21 C and −1/3 bar generally began on day 3 or 4 and near maximum emergence rates of the intermediate species occurred by day 8 at 21 C and −1/3 bar. Total emergence was less than observed for the aggressive group. Emergence was also sharply reduced at −6 and −9 bars as compared to Abruzzi rye, German millet, and perennial ryegrass. Common bermudagrass at 21 C and Sericea (Lespedeza cuneata G. Don.), and crownvetch at 28 C had few seedlings emerge until day 8 in the soil maintained at −1/3 bar, and their total emergence was the lowest of all species with near maximum occurring between day 10 and 13; therefore, they were considered non‐aggressive species. Generally, as temperature and moisture tension increased, the rate of emergence and total emergence of all species declined. Of the aggressive species, only Abruzzi rye, German millet, and perennial ryegrass had above 50% relative emergence after 19 days at a soil water potential of −9 bars and 21 C. Seed mixtures for different planting seasons should be designed with species adapted to various temperature and moisture extremes.
Physical Characteristics of Le Sueur Clay Loam Soil Following No‐till and Conventional Tillage1
Authors: Gantzer C. J. , Blake G. R. 
Published: July 2010

AbstractAlthough the effects of no‐till on crop yields has been widely investigated, there are virtually no data on its physical effects on clay loam soils like those in the Corn Belt. In order to compare the effects of no‐till with conventional fall plow tillage on a south‐central Minnesota clay loam soil (Aquic Argiudoll), we measured some soil physical properties 6 years after beginning a field experiment with corn (Zea mays L.). Data show that soil under no‐till had significantly greater bulk density, both in spring and fall, for samples in the surface 30 cm. Densities of no‐till soil ranged from 1.24 to 1.32 g/cm3 in in contrast to those of conventional tillage, which ranged from 1.05 to 1.12 g/cm3. Air‐filled porosities of surface samples under no‐till were lower at all potentials measured. At −100 rob, no‐till averaged 0.143 cm3/cm3 compared to 0.198 cm3/cm3 for conventional tillage. Mean number of channels 1 mm and greater created by earthworms and decomposed rootlets were significantly greater for no‐till, ranging from 666 to 1,732/m2 compared to 243 to 1,475/m2 for conventional tillage. Volumetric water contents were also greater for no‐till surface samples, ranging from 0.35 to 0.28 cm3/cm3 vs. 0.31 to 0.25 cm3/cm3 for conventional tillage. Saturated hydraulic conductivities of spring surface samples were lower under no‐till than conventional tillage averaging 14.6 cm/hour and 38.2 cm/hour, respectively. Generally. differences in measured parameters between treatments were smaller for samples collected in fall before harvest, than those in spring. Significant differences for tillage treatment were not found below 30 cm depth. At high water potentials, lower porosity under no‐till may restrict gaseous exchange and create conditions unfavorable for germination and seedling development. However, higher number of biochannels in the no‐till soil may compensate for this reduced exchange.
A Thermogradient Generating Sand Table1
Authors: Clegg Max D. , Eastin Jerry D. 
Published: July 2010

AbstractA need to study the effect of a wide range of temperatures on early plant growth as well as seed germination of a wide range of sorghum [Sorghum bicolor (L.) Moench] germplasm led to the construction of a sand thermogradient sand table. The table was constructed so heat was transferred between water baths of two different temperatures. A continuous, linear thermogradient was established when the water baths were at 15 and 45 C. Other temperature differentials produced nearly linear gradients. Temperature deviation at any depth during the experiments never exceeded 1 C and usually was less. Germination and early growth of sorghum and corn (Zea mays L.) were measured to demonstrate the type of response curves that could be obtained with this apparatus. The table lends itself to many applications for physiological studies, including screening genetic material for temperature tolerance.
Effect of Soil pH and Liming on Growth and Nodulation of Soybeans in Histosols1
Authors: Mengel D. B. , Kamprath E. J. 
Published: July 2010

AbstractSoil acidity severely limits the growth of soybeans [Glycine max. (L.) Merr.] on Histosols in North Carolina. Laboratory and greenhouse studies were conducted to determine the critical soil pH levels for soybean growth and the chemical factors influencing growth. Soybeans were grown on eight organic soils which had been limed with dolomitic limestone to give a pH range from 4 to 5. Lime rates were based on the CaCl2 exchangeable acidity of each soil. Measurements were made of exchangeable soil acidity, exchangeable AI and Ca, and water soluble AI and Ca. Plant variables measured were shoot, root and nodule dry weight, nodule number and concentration of N, P, K, Ca, Mg, and AI in shoots and roots. These measurements were made at 28 and 40 days after planting in order to calculate growth rates and nutrient uptake rates. Growth responses to liming were obtained on all soils. Shoot growth was significantly related to soil pH and water soluble AI and Ca. Nodule number and weight increased significantly as soil pH increased. Both N con. centration and uptake increased markedly as soil pH increased. Critical soil pH for shoot, root, and nodule growth was in the range of 4.6 to 4.8 for most of the soils. The growth responses to liming are attributed to decreasing the exchangeable and water soluble AI, increasing the water soluble Ca and providing a favorable soil pH for rhizobium activity.
Diurnal Changes in Plant Water Potential and Canopy Temperature of Wheat as Affected by Drought1
Authors: Ehrler W. L. , Idso S. B. , Jackson R. D. , Reginato R. J. 
Published: July 2010

AbstractThe diurnal courses of plant water potential (ψplant and temperature (canopy‐air) (ΔT) were determined for 4 days for a wet soil (six levels of water content, θv, corresponding to values of soil water potential (ψm) of −0.1 to −0.5 bars) as compared with a dry soil (six values of ψm, from −1.6 to −18.0 bars), established by withholding irrigations. In wet soil, ψplant decreased from near zero at predawn to −16 bars from solar noon until 1600 hours, and then returned to near zero shortly after sunset. For this treatment, ΔT increased from an initial negative value (−2 to −9 C, depending on the saturation deficit) to either the least negative or a slightly positive value near 1000 hours, and then it gradually decreased and was negative at 1400 hours in five of the six wet plots.For dry soil, the ψplant curve reasonably paralleled that for a well watered crop, but was more negative and did not necessarily return to the predawn value after sunset. For dry soil, ΔT increased rapidly after sunrise, peaked near solar noon (rather than at 1000 hours) and decreased only slightly by 1400 hours, and was positive (0.7 to 7.0 C) in all six dry plots.Because typical diurnal curves for ΔT differed in shape depending on soil water content, canopy temperatures of plants on wet and dry soils differed most near 1400 hours. Thus, it is feasible to use ΔT measured at this time to represent the whole day. Such ΔT measurements can lead to routine monitoring capabilities by remote sensing techniques.
Effect of Nitrogen Fertilization on Yield, Composition, and Quality of Kenaf1
Authors: Adamson W. C. , Long F. L. , Bagby M. O. 
Published: July 2010

AbstractKenaf (Hibiscus cannabinus L.), a potential pulp crop, has not shown a consistent yield response to N, and the influence of N on pulp quality factors is unknown. The response of kenaf to lime and the amounts of various elements removed with the harvested crop are also of interest. A field study was conducted to determine the effect of N on yield, mineral composition and quality of kenaf at two pH levels. Tests were conducted for 2 years, 1970 and 1971; in two soil areas, Edisto (Glossaquic Fragiudalf) and Ona (Typic Haplaguod); and in high and low pH areas established by, prior applications of lime. Nitrogen was applied at three levels and in single and three‐way split applications. Nitrogen increased the yield, height and diameter of kenaf. Nitrogen had the favorable effect of increasing woody fiber length, however lignin content was also increased. Cellulose content was unaffected. Split applications of N usually produced higher yields than the same amount in a single application but were only significant for the fist year on limed Edisto soil. Increasing rates of N decreased the P, K, Ca and B content of harvested kenaf. Lime increased the Mg content an1 reduced the Mn, Al, Sr, and Ba contents. Neither N or lime had any significant effect on ZnZ Cu or Mo content.
N Uptake and Corn Yield as Affected by Applications of Nitrapyrin with Anhydrous Ammonia1
Authors: Touchton J. T. , Hoeft R. G. , Welch L. F. , Mulvaney D. L. , Oldham M. G. , Zajicek F. E. 
Published: July 2010

AbstractThe use of nitrapyrin as a nitrification inhibitor of ammonium fertilizers applied to corn (Zea mays L.) has gained widespread interest. Even though initial nitrification rates are usually decreased by nitrapyrin, its use does not always result in increased grain yield. To evaluate the effects of nitrapyrin applied with anhydrous ammonia on yield and N uptake of corn grown on poorly drained soils, field studies were conducted in Illinois at Urbana, Brownstown, and DeKalb. The soil at Urbana and DeKalb was Typic Haplaquoll and Mollic Albaqualf at Brownstown. Anhydrous ammonia was applied with and without nitrapyrin in the fall and spring. Nitrapyrin and N rates ranged from 0 to 1.12 and 0 to 268 kg/ha, respectively.The addition of nitrapyrin had varied effects on N concentration in the plant tissue and on grain and total dry matter yield; however, these effects were not consistent among N rates, locations, or years. At Urbana, the addition of nitrapyrin increased the N concentration in the plant tissue at the fifth‐leaf growth stage in 1975 by as much as 7% and in the ear leaf at silk in 1976 by as much as 6%, when comparing within N rates and seasons of application. The N concentration in the grain and stover was reduced by as much as 8 and 27%, respectively, by the addition of nitrapyrin at low rates of N. At DeKalb in 1975, nitrapyrin did not affect N in the plant tissue. In 1976, applications of nitrapyrin with fall‐applied N increased N in the ear leaf up to 20% over fall‐applied N without nitrapyrin, and increased it up to the concentration found for spring‐N applications with or without nitrapyrin. At Brownstown in 1975, plants did not respond either to applied N or nitrapyrin. In 1976, plants responded to nitrapyrin, but adverse weather resulted in data that did not follow expected trends.Grain and stover‐yield increases could not be attributed to applied nitrapyrin when N was applied at levels required for maximum economical yield. Soil moisture during both years was not favorable, however, for N losses that would occur normally through leaching and denitrification.
Tolerance of Soil Acidity in Symbioses of Mung Bean with Rhizobia1
Authors: Munns D. N. , Keyser H. H. , Fogle V. W. , Hohenberg J. S. , Righetti T. L. , Lauter D. L. , Zaroug M. G. , Clarkin K. L. , Whitacre K. W. 
Published: July 2010

AbstractVariation in tolerance of soil acidity among 40 rhizobial strains was assessed in greenhouse trials in which the strains were applied as separate seed inoculants (5 ✕104 cells per seed) to two cultivars of mung bean (Vigna radiata L.) and performance was measured by nodulation, growth, and N‐yield of the host plant. The plants grew in a low N, low Ca acid subsoil, Goldridge fine sandy loam (Typic Hapludult, fine loamy, mixed, mesic), left at its natural pH of 5.0 (saturation paste) or limed with CaCO3 to pH 6.3. Each pH ✕ strain treatment was triplicated in separate pots.Strains demonstrated a large and perhaps continuous variation in acid tolerance. A few were very sensitive: they failed to nodulate at pH 5.0. About half were moderately sensitive: nodulation and growth were significantly impaired at pH 5.0. The remainder were tolerant: like NH4NO3 they supported similar plant growth at both soil pH values. Some strains combined high tolerance with high effectiveness.A strain's acid tolerance could not be predicted from the abundance or effectiveness with which it nodulated at favorable pH, or from its growth rate or acid production in conventional yeast mannitol medium.A few strains were sensitive on one host cultivar and tolerant on the other, implying that acid tolerances of symbiotic legumes cannot be compared validly in trials with only one inoculant.
Leaf and Stem Yields and Forage Quality of Three N‐fertilized Warm‐Season Grasses1
Authors: Perry L. J. , Baltensperger D. 
Published: July 2010

AbstractNitrogen fertilization of warm‐season tall grasses may increase dry matter yields, percentage crude protein, and in vitro dry matter disappearance (IVDMD). Leaf and stem portions of total dry matter may vary among grasses, years, and fertility levels and during the growing season. Established pure field stands of switchgrass (Panicum virgatum L.), indiangrass [Sorghastrum nutans (L.) Nash], and big bluestem (Andropogon gerardi Vitman) were fertilized annually with 0, 45, and 90 kg N/ha and harvested at six biweekly dates beginning in mid‐June during 1973 and 1974 to determine leaf and stem yields and forage quality of these warm‐season grasses as influenced by N‐rate and plant maturity. Leaf and total dry matter yields decline 50% following the 1st year of clipping due to below average precipitation of 1974 as compared with 1973. Leaf yields increased with N fertilization more at the later harvests. Big bluestem responded with more than double the dry matter (leaf and total) production per kg of N and showed less decline the 2nd year than the other grasses. Leaf material of all grasses comprised approximately 85% of the total forage yield at most N levels both years. Leaf crude protein percentages were increased with N fertilization during the first three harvests; whereas, leaf IVDMD ercentages were increased with N fertilizer during the first five harvests. Leaf IVDMD was highest in indian. grass followed by big bluestem and switchgrass. Rapid declines occurred in leaf crude protein and IVDMD throughout the growing season, indicating that leaf maturation primarily is responsible for declining forage quality rather than increasing plant development, i.e., increasing stem growth, in these grasses.
Variations in the Number of Seeds per Unit Weight Among Turfgrass Cultivars1
Authors: Christians N. E. , Wilkinson J. F. , Martin D. P. 
Published: July 2010

AbstractKentucky bluegrass (Poa pratensis L.) and the fine fescues (Festuca rubra L., Festuca rubra var. commutata Gaud. and Festuca ovina var. duriuscula L. Koch) are widely used turfgrasses in temperate regions. Seeding rate recommendations for these species are dependent on seed number per unit weight and are based on counts available in the literature. In recent years, however, breeding and selection have produced cultivars of these species with visible differences in seed size, yet variations in seed numbers have not been documented. This study was conducted to determine seed count variations among several cultivars of Kentucky bluegrass, fine fescue, and among individual lots of Kentucky bluegrass cultivars. Counts for the fine fescues were estimated by calculations made from the weight of 100 seeds. Kentucky bluegrass seed numbers were estimated by the above method and by an electric seed counter.Differences in seed count existed among cultivars of both turfgrasses. Fine fescue cultivars varied from 1,272 seeds/g to 618 seeds/g with a mean for all cultivars of 1,020 seeds/g. Kentucky bluegrass cultivars varied from 4,413 seedsjg to 1,847 seeds/g with a mean of 2,744 seeds/g. Significant differences in seed count were also found to exist among lots of individual Kentucky bluegrass cultivars. Differences among lots as large as 805 seeds/g for ‘Merion’ and 373 seeds/g for ‘Pennstar’ were recorded.Six Kentucky bluegrass cultivars with widely varying seed counts were established on a seed count (308 live seed/dm2) and on a weight basis (0.75 kg/are). This part of the investigation was conducted on a Typic Argiaquolls, Fine‐Loamy, mixed mesic soil at the Ohio State Univ. turf plots in Columbus, Ohio.Initially, cultivars with higher seed counts were established more rapidly than were cultivars with fewer seeds/g, when seeded at the 0.75 kg/are rate. After 6 growing months, no differences in percent cover between either seeding rate or cultivars existed. After 1 year, sod strength determinations were essentially the same among all treatments. If the goal of seeding is rapid establishment, there may be an advantage to seeding Kentucky bluegrass cultivars with fewer seeds/g (larger seeds) at a higher weight/unit area than cultivars with greater seed counts.
Corn Residue Management and Soil Organic Matter1
Authors: Barber Stanley A. 
Published: July 2010

AbstractOrganic matter in a soil results from the balance between rate of loss from decomposition of the soil organic matter and rate of gain from formation of organic matter during decomposition of crop residues and roots returned to the soil. Interest in using corn plant residues as a source of energy production raises the question of how much residue removal would reduce soil organic matter and soil productivity. Effect of residue management was studied in field experiments with corn (Zea mays L) on a Raub silt loam (Aquic Arqiudoll) near Lafayette, Ind. One experiment had continuous corn growth for 11 years with residues removed, residues returned, and double residues returned. It also had a continuous fallow treatment. A second experiment had differing levels of residues returned because of N levels used on 12‐year, continuous corn. Soil samples taken from the plow layer during and at the conclusion of the experiments were analyzed for organic carbon. Losses of organic matter from plots fallowed continuously for 6 years indicated a decomposition rate of 2.4% per year. Corn stalk residue removal for 10 years was compared with residue return. About 11% of the C in the residues was synthesized into new organic matter. In a fertility experiment, where level of residues varied with treatment, the change in soil organic matter after 12 years indicated 8% of the C in residues was transformed into C in organic matter. Corn roots also appeared to contribute at least 18% of their C to formation of new organic matter. These results are in agreement with an experiment in Iowa and can be used to estimate the effect of residue management practices on soil organic matter level of similar soils.
Statistical Designs and Response Models for Mixtures of Cultivars1
Authors: Federer W. T. 
Published: July 2010

AbstractIn spite of current interest in growing mixtures (composites) of cultivars and in multiple cropping systems, appropriate response models, definitions, treatment designs, and statistical analyses are not available when more than two cultivars are involved. Since the beneficial or detrimental effects of using mixtures of size k equal to or greater than two cultivars (lines, species) as compared to sole cropping (monoculture) needs to be assessed, the objective of this study is to present response models, treatment designs (the selection of entities or treatments for an experiment), definitions of effects, and statistical analyses for estimating and comparing the various effects involved in experiments on mixtures of k cultivars. The concepts of general mixing (blending), bi‐specific mixing, tri‐specific mixing, . . . , nth specific mixing effects are formulated. Treatment designs are derived from weighing, balanced incomplete block, and supplemented block experiment designs. It is shown that solutions for parameters in the response models are dependent upon the number and types of mixtures used in the treatment design. A statistical analysis is presented for a particular treatment design involving mixtures of all possible pairs of eight dry bean cultivars plus the cultivars themselves. Finally, it is noted that the results may be useful for a number of other types of experiments involving mixtures, such as herbicide, nutrition, medicine, education, etc.