bluuebunny/crossref_metadata_2025_split huggingface dataset:
Simple Beta Distribution Representation of Leaf Orientation in Vegetation Canopies1
Authors: Goel Narendra S. , Strebel Donald E. 
Published: July 2010

AbstractIt is shown that a two‐parameter beta distribution represents very well the leaf angle distribution for a variety of vegetation canopies. Comparison to theoretical distributions as well as field data suggests that this distribution be considered as a candidate for a “universal” leaf angle distribution. The parameters of the distribution can then be used to identify and classify intermediate canopy types and possibly to quantify canopy changes caused by environmental stress.
Syringing Effects on the Canopy Temperatures of Bentgrass Greens1
Authors: DiPaola J. M. 
Published: July 2010

AbstractSyringing of fine turf, particularly bentgrass golf greens, is practiced throughout the USA. The literature indicates that this procedure offers some potential to moderate turfgrass canopy temperature. The practical utility of syringing from canopy temperature reduction under the warm, humid conditions of the southeastern USA was examined in this study. A ‘Penncross’ creeping bentgrass (Agrostis palustris Huds.) green constructed to U.S. Golf Association (USGA) specifications and located in Raleigh, NC was subjected to eight rates of water applications (0, 0.05, 0.1, 0.7, 1.4, 2.7, 4.1, and 5.5 mm) as syringing treatments at one of two times (1100 or 1300 h) during the day. Green soil construction consisted of mixing 9 parts sand with 1 part of a Typic Hapludult Clayey, kaolinitic, thermic (Cecil gravelly sandy loam) soil and 1 part peat. The objective of a second study was to evaluate canopy temperature changes following a syringing treatment of 2.7 mm of water applied as single or multiple applications. In the absence of wilt, bentgrass canopy temperatures were not significantly altered 1 h after syringing regardless of the water volume or timing of the syringing application. Therefore, in the absence of wilt, the routine syringing of bentgrass greens must be reevaluated given the substantial economic cost of this procedure, particularly for labor and water.
Contribution of Genetic Improvement to Recent Wheat Yield Increases in the USA1
Authors: Feyerherm A. M. , Paulsen G. M. , Sebaugh J. L. 
Published: July 2010

AbstractGenetic yield potential of wheat (Triticum aestivum L. and T. turgidum L. var. durum) has increased markedly during recent decades, but its impact on production has not been well documented. Studies were conducted to measure the effect of genetic improvements from 1954 through 1979 on growers' yields of wheat in states where each major class is grown. Differential yielding ability (DYA) values were calculated for popular cultivars from a broad data base of performance trial yields and weighted by the mix of cultivars in production in each state. Yield increases attributed to changing cultivar mixes in spring wheat states ranged from 268 kg ha−1 in Montana to 550 kg ha−1 in Minnesota. Increases in the hard red winter wheat region were greatest in Nebraska (416 kg ha−1), Oklahoma (368 kg ha−1), and Kansas (348 kg ha−1) and were smallest in Texas (233 kg ha−1), Colorado (228 kg ha−1), and Montana (193 kg ha‐'). Soft wheat yield increases ranged from 739 to 854 kg ha−1 in Corn Belt states and 734 kg ha−1 in Washington State. We concluded that the impact of genetic improvement was inversely related to environmental constraints, that substantial yield improvement in unfavorable environments requires greater emphasis on stress resistance, and that no slowing of the rate of yield improvement is evident.
Stem Excision as a Means of Simulating Hail Injury on ‘Alaska’ Peas1
Authors: Miller D. G. , Muehlbauer F. J. 
Published: July 2010

AbstractAccurate assessment of stem hail injury in peas (Pisum sativum L.) resulting from excised stems is difficult to make and can cause problems in hail adjustment methods. This study evaluated stem excision and its effect upon subsequent growth and yield in fieldgrown peas. Four levels of simulated hail injury were applied to ‘Alaska’ peas previously thinned to 13, 20, 26, or 33 plants m−2. Injury treatments were made by cutting the primary stem and removing all tissue above the point of excision on plants at the rate of 0, 5, 10 or 20% of the total plant population when plants were in the eighth node (vegetative) and full‐bloom (reproductive) growth stages. Plants in the vegetative stage were excised between the fourth and fifth node (Treatment 1). Those in the reproductive stage were excised between the fist and second flowering node (Treatment 2a) or immediately below the first flowering node (Treatment 2b). Individual plant performance at all treatments showed that damaged plants had delayed maturity, reduced plant height, increased branching, and reduced seed weight when compared to undamaged plants. Seeds pod−1 were similar on damaged and undamaged plants except at Treatment 2b, where a significant reduction in seeds pod−1 was noted on damaged plants. Pods plant−1 were reduced for Treatments 1 and 2a, but not for Treatment 2b. Damaged plants recovered by initiating branches from lateral buds; however, they required 6 to 7 days more than untreated plants to reach dry seed maturity. When peas were treated in the vegetative stage, yield declined 0.41% for each 1% increase in damaged plants. Yield declines of 0.59% for Treatment 2a and 0.85% for Treatment 2b were obtained for each 1% increase in damaged plants in the reproductive stage. This information concerning plant recovery from excised stem damage and yield compensation by undamaged plants should make hail damage adjustment in peas more precise.
Harvesting Losses of Spring Wheat in Windrower/Combine and Direct Combine Harvesting Systems1
Authors: Clarke John M. 
Published: July 2010

AbstractHarvest loss of cereal crops has been reported to be reduced by windrow‐drying prior to combing compared to direct combining, but few comparisons of the two systems have been made. Field studies were conducted in order to compare harvesting losses of five wheat (Triticum spp.) cultivars of varying shattering resistance in direct combine and windrower/combine harvesting systems on a Swinton loam soil (Aridic Haploboroll). Cutting treatments were initiated when kernel water concentration was about 670 g water per kg kernel dry weight and continued for at least 2 weeks after kernel water concentration reached 170 g kg−1. Natural shattering losses and cutting losses were measured at each cut; combine pick‐up losses were measured when the windrows were combined. Cutting and pickup losses did not change with cutting time and there was no consistent variation among cultivars. Cutting losses ranged from 0.75 to 3.03 g m−2; pick‐up losses ranged from −0.10 to 0.98 g m−2. Natural shattering losses varied with cultivar and year; cummulative loss ranged from a low of 4 to a high of 27 g m−2 over a period to some 2 weeks after kernel water concentration reached 170 g kg−1. Harvesting losses were similar for the two harvesting systems for cultivars resistant to shattering, but greater for the direct combine than for the windrower/combine system for cultivars susceptible to shattering. An earlier start to direct combining (at kernel water concentrations of 170 to 250 g kg−1) narrowed the difference between the systems for cultivars susceptible to shattering as did delayed windrowing.
Emergence of Inbred and Hybrid Corn Following Flooding1
Authors: Fausey N. R. , McDonald M. B. 
Published: July 2010

AbstractWhile it is commonly accepted that the Occurrence of excess soil water following planting adversely affects the establishment and early growth of corn (Zea mays L.) seedlings, the effect of flooding duration, soil temperature at time of flooding, and cultivar have not been determined. Such information would be useful to drainage system designers and corn breeders. The objective of this study was to determine whether pregermination flooding duration and soil temperature at time of flooding affect the emergence of selected inbred and hybrid corn cultivars. Five popular inbred [A632, B37, B73, H60, and Mo17] and five hybrid [(A635 ✕ A632)Mo17, B73 ✕ H60, (H95 ✕ H99) A632, (OH514 ✕ OH7B)H95, Mol7 ✕ B73] corn cultivars grown in Ohio were exposed immediately following planting to differing durations of flooding (0,48,96, and 144 h) at two temperatures (10 and 25 °C) in the laboratory and at cold (near freezing) and warm (approximately 25 °C) temperatures in a silty, clay, loam Typic Argiaquoll soil in the field. Seedlots were selected which possessed a germination percentage above 90. Laboratory and field results showed inbred cultivars to be more tolerant of flooding than hybrid cultivars. Flooding damage as measured by reduced emergence was noted in both inbred and hybrid cultivars after only 48 h flooding in both laboratory and field studies. The severity of flooding damage was enhanced for both cultivar groups when flooding temperature was increased from 10 to 25 °C.
Nitrogen from Forage Legumes: Harvest and Tillage Effects1
Authors: Groya F. L. , Sheaffer C. C. 
Published: July 2010

AbstractIncreasing interest in forage legumes as green manures in crop rotations has emphasized the need for information on harvest and tillage management of modern cultivars. Our objectives were to: 1) determine the effects of four seeding year harvest managements on sweetclover [Melilotus officinalis (L.) Lam.], red clover (Trifolium pratense L.), and alfalfa (Medicago sativa L.) herbage and root dry matter (DM) and N yields, and on DM yield and N recovery by a subsequent sudangrass [Sorghum bicolor (L.) Moench] crop, and 2) determine the effect of moldboard or chisel plowing on DM yield and N uptake by sudangrass grown following incorporation of alfalfa residues. Two separate experiments were conducted on a fine‐silty over sandy‐skeletal, mixed, mesic Typic Hapludolls. With a hay harvest management (three or four harvests), legumes had similar total season herbage N yields (261 kg ha−1), and root DM (1.4 Mg ha−1) and N yields (30 kg ha−1), and total plant N yields (325 kg ha−1). Unharvested sweetclover had greater fall whole plant N yields (348 kg ha−1) than alfalfa (195 kg ha−1) and greater root DM (5.1 Mg ha−1) and N yields (175 kg ha−1) than alfalfa or red clover (average root DM and N yields of 1.9 Mg ha−1 and 48 kg ha−1, respectively). Nitrogen incorporation (272 kg ha−1) was greater when legume herbage was accumulated in situ than when herbage was removed and only fall regrowth and/or crowns and roots incorporated (86 kg ha−1). Legume species selection within harvest management had little effect on sudangrass DM yield or N uptake. Tillage method had no consistent effect on sudangrass, DM yield, or N uptake. Since fallowing resulted in sudangrass yields similar to those from the best legume treatments, it might be considered as an alternative to legume production for diverted cropland on some soils.
Predicting Rice Grain Yield from Dry Matter Production at Late Tillering1
Authors: Gilmour J. T. 
Published: July 2010

AbstractIt was hypothesized that grain yield of rice (Oryza sativa L.) was related to dry matter accumulation at late tillering. Using published data from N rate and timing studies conducted in Arkansas on Crowley silt loam (fine, montmorillonitic, thermic Typic Albaqualf) and in the Philippines, this hypothesis was tested by regressing relative grain yield against relative dry matter production at late tillering. A linear, highly significant relationship which had a slope of 0.52 and intercept of 40% was obtained. In this equation, the dry matter and grain yield were expressed as a percentage of an unfertilized control. The mean relative growth rates after late tiilering were relatively constant irrespective of N management which explained, in part, the influence of dry matter at late tillering on grain yield for these data. Application of this relationship to specific plant‐soil‐climate situations to predict and/or increase grain yield are potential uses of these findings.
New Hand‐Operated Press for the Extraction of Tissue Sap for the Measurement of Osmotic Potential1
Authors: Markhart Albert H. , Lin Tsai‐Yun 
Published: July 2010

AbstractConventional methods of extracting sap from leaf tissue for the measurement of osmotic potential are time consuming and often result in changes in sap concentration due to evaporation or enzymatic activity. In this paper, a simple hand operated press is described which facilitates rapid extraction and filtration of tissue contents with either direct deposition on a filter paper disk for osmotic potential measurement or collection in a suitable vial for future analysis. A complete measurement is made in 5 min. Triplicate measurement of samples with the same osmotic potential differed by an average of 0.05 MPa at an osmotic potential of −0.7 MPa. Osmotic potentials measured with a vapor pressure osmometer on expressed sap were 10% higher than values derived from pressure volume carves. This error is most likely due to dilution of the protoplasm by the cell wall water. Convenience and reliability make this new press a useful tool for the water relations laboratory.
Linear Increase in Soybean Harvest Index during Seed‐Filling1
Authors: Spaeth S. C. , Sinclair T. R. 
Published: July 2010

AbstractGrain‐to‐stover ratio and harvest index (the ratio of seed mass to total aboveground mass) were studied during soybean [Glycine max (L.) Merr.] seed‐filling to determine the potential for using these normalized expressions of yield to improve measurements of the seed‐filling period. For example, if either grain‐to‐stover ratio or harvest index increased linearly during seed‐filling, it could be used to calculate an effective filling period. However, calculation of an effective filling period requires a linear approximation. Thus, the specific objective was to determine whether grain‐to‐stover ratio or harvest index increased as a linear function of time for various genotypes and environments. First, C and N assimilation and distribution rates within plants were simulated. Simulations predicted that harvest index increased linearly throughout seed filling, while grain‐to‐stover ratio increased curvilinearly. Next, simulations were compared with data from field‐grown plants at three northern locations. Cultivars included determinate and indeterminate types, and a range from early to late maturities. To a good approximation, harvest index increased linearly during the seed‐filling period for all but the early cultivars. The early cultivars approached maximum values of harvest index curvilinearly. Therefore, harvest index has potential for use in calculations which require linear approximations.
Potato Tubers and Soil Aeration1
Authors: Cary J. W. 
Published: July 2010

AbstractPotato plants are more sensitive to soil oxygen stress than many other common crops. Some recent literature suggests this may be due to a relatively high oxygen requirement for tuber growth, rather than a greater requirement for the roots per se. Consequently, the oxygen consumption of growing potato tubers (Solanum tuberosum cv. Russet Burbank) was measured in the field on a Portneuf silt loam (coarse‐silty, mixed, mesic Durixerallic Calciorthid). Typical rates were 15 µg O2 cm−2 hr−1. A simple method for measuring soil oxygen diffusion rates in the laboratory was then devised, utilizing an oxygen meter and a stream of N2 gas. Soil conditions such as texture, bulk density, compaction around expanding tubers, oxygen sinks and water contents were studied with respect to their relative effects on limiting oxygen uptake by tubers. The minimum soil oxygen diffusion coefficient required for adequate tuber aeration is quite sensitive to the soil respiration rate and the depth of soil covering the tubers. Water contents of “field capacity” or a little wetter were found to not necessarily inhibit tuber aeration in loamy sand, silt loam, and silty clay soils provided the bulk densities were not excessive; i.e., greater than 1.6 or 1.7 Mg m−3 in the silt loam. Reduced aeration due to compaction around growing tubers is a possibility in the silty clay, but probably not in well drained silt loam or loamy sand. The criteria for a minimum acceptable soil oxygen diffusion coefficient must be based on tuber periderm permeability, soil ethylene generation, and other anaerobic soil reactions, as well as tuber respiration per se.
Phosphorus Efficiency and Phosphate–Iron Interaction in Maize1
Authors: Elliott George C. , Läuchli André 
Published: July 2010

AbstractGenotypic differences in absorption or utilization of P might be exploited to improve efficiency of fertilizer use or to obtain higher productivity on P‐deficient soils. Experiments were conducted to determine rates of P absorption, P accumulation, and P utilization in 15 inbred genotypes of maize (Zea mays L.) at 3 P supply levels. Nutrient solution P concentrations were maintained at approximately 5,25, and 100 mmol m−3 (P1, P2, and P3, respectively) with an alumina‐P solid phase buffer. There were significant differences among genotypes for rate of P utilization, but not for rate of P absorption by roots. Utilization of P was negatively correlated with the ratio of inorganic P accumulation rate to total P accumulation rate, indicating that P utilization is limited by partitioning of P between free orthophosphate and organically combined forms. Absorption of P by roots and utilization of P in shoots were positively correlated. Iron deficiency occurred with all genotypes grown in the P2 and P3 treatments, but not in the P1 treatment. Both Fe absorption by roots and partitioning of Fe to shoots decreased with increasing concentration of P in the nutrient solution. Utiliition of Fe (rate of dry matter production per unit of Fe accumulated) in shoots increased in Fe‐deficient plants. Phosphate‐induced Fe deficiency in maize evidently involves both inhibition of Fe absorption by roots and inhibition of Fe transport from roots to shoots.
Grain Yield and Yield Components of Soft Red Winter Wheat as Affected by Management Practices1
Authors: Frederick J. R. , Marshall H. G. 
Published: July 2010

AbstractThe use of intensive management practices could substantially increase soft red winter wheat (Triticum aestivum L. em Thell.) grain yields in the northeastern USA, but more information is needed about the influence of management factors on components of yield. Our objective was to determine the effects of seeding rate, row spacing, seeding depth, and rate of spring‐applied N fertilizer on grain yield components and to calculate the yield changes associated with changes in the yield components. ‘Roland’ wheat was grown on eight Pennsylvania farms during 1981 and 1982 on either Typic or Ultic Hapludalf soils. Treatments were row spacings of 12.7 and 17.8 cm, seeding depths of 1.9 and 3.8 cm, seeding rates of 101,168, and 235 kg ha−1 and spring N topdressing rates of 0, 34, 67, and 101 kg ha−1. Plot subsamples were used to determine grain yield, tiller number, kernel number per tiller, and kernel weight. The over all treatment means for locations ranged from 291 to 420 g m−2 for yield, 440 to 585 for tillers m−2, 20.0 to 27.6 kernels/tiller, and 27.2 to 35.5 g/l000 kernels. Kernel number per tiller appeared to be consistently below genetic and phenotypic potentials. Yield changes associated with increasing levels of N varied from positive to negative quadratic responses at the low and high yielding sites, respectively. The primary component of yield decreases was reduced kernel weights. Increasing the seeding rate beyond 101 kg ha−1 always resulted in increases in tiller number and decreases in the number of kernels per tiller while increases in kernel weight occurred at six locations. When row spacing was decreased to 12.7 cm, grain yields increased by an average of 8.2%, and the primary contributing component was more tillers per unit area. This was the only treatment without consistent negative responses in at least one other yield component. Increasing planting depth to 3.8 cm reduced the number of tillers and was associated with increased kernel number per tiller at most locations. The only yield change was a decrease at a location where planting date was delayed.
Soyphen: Soybean Growth Stages Modeled from Temperature, Daylength, and Water Availability1
Authors: Hodges Tom , French Vikki 
Published: July 2010

AbstractThe soybean plant (Glycine max L.) responds strongly to daylength and temperature in its phasic development. Daylength responses vary greatly between varieties. Under very dry conditions, water stress may also affect development. Attempts to develop physiologically based large area yield models for soybeans have been hampered by the lack of a growth stage model incorporating these responses and applicable to a wide geographic and climatic range. The objective of this work was to develop a physiologically based model to predict growth stage dates for soybeans for the widest possible range of maturity groups and geographic areas. A phenology model was developed and tested for soybean Maturity Groups I to V based on temperature, daylength, and water availability. Coefficients were also developed, but not tested independently for Maturity Groups 00, 0, and VI to IX. Coefficients for Maturity Groups I to V were developed from 3 years (1971 to 1973) of data with five planting dates per year collected at Columbia, MO. The coefficients were tested on data sets taken at the same time at Spickard and Mt. Vernon, MO and on data for the 1981 season from 22 international sites. The test results indicate that the model will generate reliable estimates of soybean growth stages over a wide range of climatic conditions. The coeffients for Maturity Groups 00, 0, and VI to IX were developed from data from international sites, but no data were available for independent testing. The model is available in the FORTRAN and PL/I programming languages. It is suitable for incorporation into a soybean growth simulation model or for running as an independent crop calendar model. The model may be run wherever daily maximum and minimum temperatures and rainfall are available.
Plant Accumulation and Soil Sorption of Cobalt from Cobalt‐Amended Soils1
Authors: Pinkerton B. W. , Brown K. W. 
Published: July 2010

AbstractPresent industrial uses of Co result in elevated metal concentrations in soils around industrial activities and land treatment facilities. Laboratory and greenhouse studies were conducted to determine Co uptake by tall fescue (Festuca arundinaceaSchreb.) as affected by soils, Co levels, lime additions, Mn additions, and soil layering. In a laboratory sorption study using solutions containing 5 to 1000 mg Co L−1, the Marietta (Aquentic Dystrochrepts) and Norwood (Typic Udifluvent) soils had sorption maxima of 1440 and 3787 mg Co kg−1, respectively. The higher sorption of the Norwood soil was presumably due to the formation of complexes or precipitates between the CaCO3and Co. Addition of up to 6.7 Mg lime ha−1resulted in decreased concentrations of Co in tall fescue grown in soils containing 400 mg Co kg−1. Addition of 50 to 2000 mg MnO2kg−1soil had no effect on Co accumulation by tall fescue. Layering of uncontaminated soil over Co‐amended soil increased plant uptake of Co over that taken up by plants grown in Co‐amended soil alone. Apparently, the healthy roots in the upper layers of soil removed Co from the lower layers of soil; whereas, elevated Co in the total soil volume retarded root development sufficiently to prevent Co uptake. Total Co determinations were as good as or better than any of the three extractants (2.5% acetic acid, 0.01 MEDTA [ethylenediamine tetracetic acid] and DTPA‐TEA [diethylenetriamine pentacetic acidtriethanolamine]) in predicting plant accumulation of Co. Of the tested extractants, acetic acid had the lowest correlation coefficient when compared with plant Co accumulation.