bluuebunny/crossref_metadata_2025_split huggingface dataset:
Moisture Stress and N Redistribution in Soybean1
Authors: Egli D. B. , Meckel L. , Phillips R. E. , Radcliffe D. , Leggett J. E. 
Published: July 2010

AbstractThe redistribution of N from vegetative plant parts to the developing seed of soybean [Glycine max (L.) Merr.] may influence the duration of seed filling and yield. The objective of this study was to investigate the effect of moisture stress during various developmental stages on N redistribution. Soybean (cv. Williams) was grown in the field at Lexington, Ky., for 3 years (1979 to 1981) on a Maury silt loam (fine, mixed, mesic Typic Paleudalf) soil. Irrigated controls were compared with moisture stress treatments from planting to beginning seed fill (growth stage R5), during seed filling (growth stage R5 to R7) or throughout the growing season. Stress was applied by not irrigating until the soil water potential reached – 300 9 kg−1 or by covering the soil with black plastic after emergence to allow severe stress to develop. Plant weight at growth stage R5 and yield were affected by the moisture stress treatments; however, moisture stress had only a limited effect on N concentration in the plant tissue. The proportion of seed N that came from redistribution varied among treatments and years from 33 to 102% and there was no consistent relationship between the level or timing of moisture stress and the contribution of redistributed N to seed N. The proportion of the N in the vegetative plant and pod walls that was redistributed was nearly constant across treatments and years. The data suggest that the contribution that redistributed N makes to the seed N at maturity is more closely related to the amount of N available for redistribution than it is to the ability of the plants to obtain N from the soil or via N2 fixation during seed filling.
Nitrogen and Yield as Related to Water Use of Spring Barley1
Authors: Kallsen C. E. , Sammis T. W. , Gregory E. J. 
Published: July 2010

AbstractThe water‐production function is the relationship between marketable crop yield and seasonal evapotranspiration. Variability in the parameters of the function for different growing seasons result in error in estimating the effect of a water management strategy on yield. The present study was conducted to determine if the parameters describing the functional relationship between transpiration and yield for field‐grown spring barley (Hordeum vulgareL.), was stable for different levels of nitrogen fertility and seasonal differences in the atmospheric evaporative demand. A sprinkler‐line‐source was used to impose different irrigation treatments and seasonal evapotranspiration resulting from these treatments was calculated by a water budget technique. Soil‐water evaporation was estimated using equations taken from the literature and transpiration was calculated by subtracting the estimated evaporation from evapotranspiration. The experiment was done on a sandy loam soil, Typic Calciorthid (coarse, loamy, mixed, calcareous, mesic family), which resulted in frequent light irrigations being applied to maintain the barley at the sprinkler line under non‐moisture stress conditions. The water‐production function was found to vary significantly among N‐fertility levels, and between seasons. However, a constant linear relationship existed between grain yield and transpiration, independent of seasonal differences in evaporative demand, or the level of nitrogenfertility in the field.
Comparison of Experimental Designs Used to Detect Changes in Yields of Crops Exposed to Acidic Precipitation1
Authors: Evans Lance S. , Thompson Keith H. 
Published: July 2010

abstractA comparison of experimental designs used to detect changes in yield of crops exposed to simulated acidic rain was performed. Seed yields were determined from field‐grown soybeans (Glycine max L.) exposed to simulated rainfalls in which all ambient rainfalls were excluded by automatically moveable rainfall exclusion shelters. When all eight, 4 ✕ 4 , latin squares were used, simulated rainfalls of pH 4.1,3.3, and 2.7 exhibited yields 10.6,16.8, and 23.9%, respectively, below yields of plants exposed to pH 5.6. The linear component of pH treatment differences showed a highly significant decrease in yield (p < 0.001). The eight latin squares analyzed as individual experiments yielded erratic conclusions. However, when all eight latin squares were combined a satisfactory evaluation can be made. The low probability value for differences among latin squares (p < 0.005) indicates that field locations are a legitimate source of stratification. Sources of variation are also highly significant for both pooled among rows within squares (p = 0.0028) and the pooled among columns within squares (p = 0.0168) indicating that the two stratifications within each latin square was doubly effective in reducing the residual error term. The relative efficiency of the latin square to a randomized complete block design, and a completely randomized design was 132‐146 and 162%, respectively.
Protein and Mineral Concentrations of Selected Wild Sunflower Species1
Authors: Seiler Gerald J. 
Published: July 2010

AbstractAlthough wild sunflowers (Helianthusspp.) can be components of pastures, hay, and silage, limited information is available on the forage‐quality of sunflower species. The objective of this study was to evaluate wild species of sunflower for protein and mineral concentrations. The experiment had a completely randomized design with three replications. The plots were planted in Pullman clay loam (fine, mixed, thermic Torrertic Palenstolls) soil. The leaves and stems of 26 perennial and one annual wild Helianthusspp., and a commercial annual sunflower hybrid planted in pure stands were evaluated at vegetative, flowering, and fruiting stages to ascertain their nutritive value for ruminants. Crude protein (CP) of 140 g kg−1and above occurred in the leaves of 11 of the 26 perennial species at the vegetative stage. At the flowering stage, only two of the 26 perennial species had CP concentrations above 140 g kg−1in the leaves. Willow‐leaf sunflower (Helianthus salicifoliusDieter) had the highest leaf CP (180 g kg−1) at the vegetative stage. Wild annual sunflower (H. annuusL.) and the commercial ‘Hybrid 894’ had leaf CP concentrations above 140 g kg−1at all stages of maturity. Crude protein concentrations generally declined as plants matured. Crude protein concentrations of seeds were higher in most of the perennial sunflower species than in the wild annual or commercial sunflower. Nutritionally, adequate amounts of Ca (2 to 5 g kg−1), Mg (2 g kg−1), and K (8 g kg−1) were present in the leaves and seed of all wild sunflower species and commercial sunflower. The leaves and stems of all species except the Arizona sunflower (H. arizonensisR. Jackson) had sub‐optimum P levels for high‐producing ruminants. Nutritionally adequate amounts of P (3 g kg−1) were present in seeds of all sunflowers examined. At the vegetative stage, nutrient level of some of the wild perennial sunflowers is comparable to that of cultivated sunflower. Ruminants most likely would not graze pure stands of wild sunflower, but would graze it in mixed stands with other forbs and grasses. The wild sunflower species may also be incorporated in hay or silage and still offer a satisfactory nutrition level.
Predicting Sand Content of Modified Soil Mixtures from Sand, Soil, and Peat Properties1
Authors: Taylor D. H. , Blake G. R. 
Published: July 2010

AbstractObtaining a specified texture in a sand‐soil‐peat mixture after mixing by a contractor requires some assumptions on the part of the soil/turf scientist. Its estimation depends on calculations based on analysis of the individual components and knowledge of bulk density values for the sand, soil, and peat. Its conformance to the specifications depends on the skill and care of the mixing operator as well as on the accuracy of the analyses. The purpose of this research was (1) to determine the mean values and variation of bulk densities of sand, soil, and peat found at construction sites and, (2) to determine the effects on sand content of the resulting mixture of variations in the following: mixing volume ratio of sand, soil, and peat; sand content of the soil component; sand content of the peat; and bulk densities of the individual components. The mean bulk densities of sands and soils found at soil mixing sites were 1.57 and 1.19 Mg/m3, respectively. The bulk densities of peats with organic contents greater than 75% by weight varied from 0.11 to 0.20 Mg/m3. A simulation model showed that the volume ratio needed to obtain a specified sand content varied considerably depending on the texture of the soil used in the mixture. To achieve 90% sand in the mixture using a hypothetical silt loam required a sand‐soil‐peat volume ratio of 7‐1‐1 while a mixture using a sandy loam soil required a volume ratio of 3‐1‐1. Relative to mixing volumes and soil texture, other variables had minor effects on the sand content of the resulting mixture. A simulation nomograph allows one to specify a sand‐soil‐peat mixing ratio to obtain a given sand content in the resulting mixture.
Drought and Flooding Effects on N2Fixation, Water Relations, and Diffusive Resistance of Soybean1
Authors: Bennett J. M. , Albrecht S. L. 
Published: July 2010

AbstractSymbiotic N2fixation depends on an interaction between bacteria and a host plant and is affected by both aerial and below‐ground environments. The specific objectives of this study were to determine the effects of drought and flooding on nitrogenase activity of soybeans [Glycine mar(L.) Merr.] growing in sandy soils and to relate the changes in activity to the availability of soil water and to observed stress responses of the shoot. Three greenhouse experiments were conducted in which plants were subjected to drought or flooding for 14 days. During the stress periods, midday measurements of gravimetric soil water content, leaf water potential (ΨL) leaf diffusive resistance, nodule water potential (Ψmod) and nitrogenase activity were collected. Flooding of soybeans for 14 days had little effect on (ΨL), leaf diffusive resistance, or (Ψmod). Although some initial leaf yellowing and structural alterations of the root and crown were apparent in the flooded plants, the nitrogenase activities of nodules after removal from the flooded environment were similar to those of the controls by the termination of the experiment. Data from drought stressed plants indicated a very sensitive response of nitrogenase activity to reductions in (Ψmod) and further suggest that nodules surrounded by dry soil may desiccate to water potentials lower than those observed for leaf tissue. Even after water deficits reduced midday N2fixation to near zero for several days, rewatering restored activities to values equal to or above those of well‐watered plants. Reduced rates of nitrogenase activity were observed as (ΨL) decreased and diffusive resistance increased.
Establishment Characteristics of Kentucky Bluegrass‐Perennial Ryegrass Turf Mixtures as Affected by Seeding Rate and Ratio1
Authors: Brede A. D. , Duich J. M. 
Published: July 2010

AbstractMixtures of grass species are desirable in a lawn for genetic diversity and to help ensure against establishment failures. Furthermore, it has been suggested that mixtures may potentially outperform monocultures of their components in terms of foliar density and possibly other factors. The purpose of this study was to determine the effects of various seed ratios (1:0, 3:1, 1:1, 1:3, 0:1) and rates (60 to 480 field‐viable seeds dm−2) of Kentucky bluegrass (Poa pratensis L., cv. Touchdown) and perennial ryegrass (Lolium perenne L., cv. Penfine) on leaf area index (LAI), shoot density, shoot size, species composition, ground cover, and clumping of the two grasses in the field. The treatments were based on field‐ viable‐seed ratios, which required data on the field survival, purity, and seeds g−1 of the seedlots. The soil was a Hagerstown silt loam (a fine, mixed, mesic Hapludalf). A shoot‐sizing technique was developed for the rapid measurement of LAI in turf stands. Using this method, results could be obtained with accuracy similar to direct area measurements but in less time. Mixtures tended to outperform monocultures by 8% in LAI, by 14% in shoot density (2 months after establishment), by 11 and 6% in foliar ground coverage (at 1.4 and 3 months, respectively), and by 44% in spring greening. A bluegrass ‐ ryegrass mixture containing 70 to 95% bluegrass field‐viable seeds provided the best compromise between adequate establishment of the bluegrass and minimal clumping of the ryegrass, which often occurs at low ryegrass seed densities. A seeding rate of 196 field‐viable seeds dm−2 produced a peak LAI value at 2 months after planting. No benefit was derived, in terms of leaf area, shoot density, or shoot size, from exceeding this rate. Low seeding rates of bluegrass and high rates of ryegrass tended to produce plants with the thinnest leaves during establishment. Shoot number, mass, and size of the two species were also affected by seeding rate and ratio.
Foliar Application of N and Fe to Kentucky Bluegrass1
Authors: Yust A. K. , Wehner D. J. , Fermanian T. W. 
Published: July 2010

AbstractThe goal of the professional lawn care industry is to provide the homeowner with a dark green weed‐free lawn. Members of this industry are interested in techniques to enhance the color of a turfgrass stand in lieu of excessive N fertilization. The purpose of this research was to evaluate the use of foliar applications of Fe alone or in combination with N on the color response of Kentucky bluegrass (Poa pratensis L.). Iron sulfate or an iron chelate was applied at the rate of 1.1, 2.2, or 4.5 kg Fe ha−1 in combination with either 0, 25, or 49 kg N ha−1 to a mixed ‘Columbia’/‘Touchdown’ Kentucky bluegrass turf growing on a Catlin silt loam (flne‐silty, mixed, mesie Typic Argiudoll). Color ratings and clipping weights were determined on a weekly basis until treatment effects were no longer significant. In a separate experiment, both sources of Fe were applied at rates of 1.1 to 72.4 kg Fe ha−1 to Kentucky bluegrass to evaluate phytotoxicity. The color enhancement due to Fe applications without N lasted from several weeks to several months depending on the weather following application. Use of Fe during cool wet periods enhanced turf color for only 2 to 3 weeks and therefore, was considered of limited value. Iron applications during cool dry periods enhanced turf color for several months. The treatment of 2.2 kg ha−1 of Fe from iron chelate was judged to be the most effective Fe treatment because the color enhancement was usually equal to that provided by a 4.5 kg rate of either source but it did not result in any discoloration as was found with the 4.5 kg rate. Combining Fe with the 25 kg ha−1 rate of N resulted in color enhancement equal to that caused by applying 49 kg ha−1 of N alone. The results of the study indicate that combining Fe with N can result in acceptable turfgrass color with lower rates of N. No permanent damage was caused to turfs receiving Fe at rates up to 72.2 kg ha−1 although foliar phytotoxicity was observed.
Regional‐Scale Estimates of Surface Moisture Availability from GOES Infrared Satellite Measurements1
Authors: Carlson Toby N. , Rose Fred G. , Perry Eileen M. 
Published: July 2010

AbstractA method for obtaining remotely a measure of surface moisture, called moisture availability, is derived here using satellite infrared surface temperature measurements in conjunction with a numerical boundary layer model. Results are presented largely in the form of a statistical comparison between rainfall (antecedent precipitation index) and soil moisture patterns. Moisture availability patterns were determined from Geostationary Operational Environmental Satellite (GOES) thermal infrared temperature measurements for 12 days during the dry summers of 1978 and 1980 over eastern Kansas and southeastern Nebraska. Representative analyses of moisture availability are presented, along with a summary of results for all cases. A significant correlation was found between M and the antecedent precipitation (API) for virtually all 12 days analyzed. The relationship between M and API can be expressed as a log‐linear one: API (cm) = 0.32 (2a, where n = a + bM and a ∼ 0.9 and b ∼ 2.2. Agreement between M and API was poorest on the smallest scales, for reasons which are discussed in the text. The relatively narrow range of API values over which M is sensitive to changes in rainfall suggest that the infrared method is most suitable for deriving surface moisture availability over plains or semiarid vegetation and where there are large horizontal precipitation gradients. The accuracy of the method may permit inference of percent soil moisture over the rooting depth of plants to within plus or minus 10 to 20%, at least when averaged over a regional‐scale domain.
Salt Effects on Seedling Growth and Ion Uptake of Three Pecan Rootstock Cultivars1
Authors: Miyamoto S. , Gobran G. R. , Piela K. 
Published: July 2010

AbstractSalt damage is often reported in irrigated cultivation of pecans (Carya illinoensis K.), yet little is known about the concentration or the salt element present in soils, which causes the damage. This study was conducted to evaluate the effects of salinity, Na and Cl on growth and ion uptake of pecan seedlings used as rootstock. The seedlings of three cultivars (‘Apache’, ‘Burkett’, and ‘Riverside’) were grown for 2 years in outdoor lysimeters containing fine loamy sand (calcareous, mixed, thermic, Typic Torripsaments). They were irrigated with eight different qualities of water; four of which had salinity levels of 0.8, 2.1, 3.4, and 6.2 dS m−1 and the additional four containing greater proportions of Na, Cl, or CaSO4. Seedling growth evaluated in terms of leaf, stem, and root weights was inversely related to Na concentrations in soil solutions as well as Na contents of seedling leaves with r values generally exceeding 0.90. The concentrations of Na in soil solutions corresponding to 25% reduction in seedling growth were approximately 40 mmol L−1 for Apache and Burkett, and 50 mmol L−1 for Riverside. Leaf Cl contents correlated neither with Cl concentrations in the soil solutions nor with seedling growth. Seedlings of Riverside absorbed substantially lesser amounts of Na and produced equal or greater root mass, and may be better suited as rootstock in saline areas.
Preharvest And Postharvest Dormancy In Spring Triticale
Authors: Salmon D. F. , Helm J. H. 
Published: July 2010

AbstractSusceptibility to sprouting is a major production problem for spring triticale (X TriticosecaleWittmack) grown in areas of Canada with high rainfall during the harvest period. During 1982 and 1983, seven spring triticales and three spring wheats (Triticum aestivumL. em. Thell) were evaluated for preharvest and postharvest dormancy. for the evaluation of preharvest dormancy, primary, secondary, and tertiary spikes were collected 1 week prior to harvest. Seed was germinated for up to 96 h at a temperature of 18 ± 1 °C. Postharvest dormancy was based on seed from random spikes collected at harvest and stored for 3 months on the shelf and in a freezer at approximately 20 and − 20 °C, respectively. Seed from each storage temperature was rated for germination using temperatures of 18 and 30 ± 1 °C for up to 72 h. In both years, primary, secondary, and tertiary spike seed provided similar rankings of lines and cultivars for preharvest sprouting. The sprouting‐resistant red seeded wheat line, RL4137 the red seeded utility wheat cultivar Glenlea, and the triticale line 7431A‐68E4 showed the most consistent levels of preharvest as well as postharvest dormancy over the 2‐yr period. The 30 °C germination temperature identified lines and cultivars with low levels of dormancy not expressed at 18 °C. Regardless of the seed source, collection date, or germination temperature, none of the experimental lines and cultivars approached the dormancy of RL4137.
Potato Top Growth as Influenced by Day‐Night Temperature Differences1
Authors: Benoit G. R. , Grant W. J. , Devine O. J. 
Published: July 2010

AbstractPast work has considered plant growth as a function of average or constant temperatures and has not evaluated the affect of diurnal temperature variations on growth. This study was conducted to evaluate the growth response of potato plant tops (Solanum tuberosumL.) to exposure to 72‐h controlled‐temperature treatments consisting of 14 different day‐night temperature combinations. Day‐night temperature differences ranged from 0 to 30°C with no night temperature ever exceeding a given day temperature. Ten potato plants were grown in individual pots in a greenhouse for each treatment with the treatment accomplished by inserting the plants into a growth chamber for 72 h at two stages of vegetative growth. Plants were maintained under “nonlimiting” soil moisture conditions. Growth was measured as increase in plant height and leaf area during the treatment period. Developed equations (all significant at P<0.01) express plant growth (plant height and leaf area) as a function of the combined influence of maximum and minimum temperatures at both growth stages. The data suggest that each maximum daytime temperature has an optimum night temperature for growth. In general, the difference in temperature between the maximum temperature and its optimum minimum temperature increases as the maximum temperature increases. Plant growth models should incorporate functions that include day‐night temperature effects on growth.
Yield and Regrowth Characteristics of Alfalfa Grazed with Sheep. I. Spring Grazing1
Authors: Allen V. G. , Wolf D. D. , Fontenot J. P. , Cardina J. , Notter D. R. 
Published: July 2010

AbstractGrazing alfalfa (Medicago sativa L.) in early spring would provide high quality pasture prior to using the forage for subsequent hay production. ‘Arc’ alfalfa grown on Groseclose silt loam (clayey, mixed, mesic Typic Hapludult) at Blacksburg, VA, was grazed by sheep beginning 6 Apr. 1981 and 1982 for four grazing durations (GD) of 0,2,4, and 6 weeks. Two experiments were conducted which differed in level of available forage (AF); high (to maintain about 0.9 Mg ha−1 and low (to maintain less than 0.4 Mg ha−1). The GD's were replicated four times within each AF as two experiments on adjacent sites. Non‐grazed alfalfa was harvested as hay at late bud stage. Regrowth on all treatments was harvested at 1/10 bloom during the remainder of the season. Increasing GD at either AF had no adverse effects on alfalfa stands in 1981. In 1982, grazing for 6 weeks at either AF reduced plant regrowth compared to non‐grazed alfalfa. Respective yields of two hay harvests in 1983 were 5.5,5.3,4.6, and 5.9 Mg ha−1 for 0‐, 2‐, 4‐, and 6‐week GD treatments at high AF, and 5.8,6.2, 5.5, and 5.1 Mg ha−1 at low AF. Results indicate that alfalfa in similar soil‐climatic regions can be grazed beginning in early spring for 4, and possibly 6, weeks for two consecutive years with minimal influence on stand longevity and productivity, particularly if AF is maintained at about 0.9 Mg ha−1.