bluuebunny/crossref_metadata_2025_split huggingface dataset:
Molybdenum Concentration of Certain Crop Species as Influenced by Previous Applications of Molybdenum Fertilizer1
Authors: Hawes R. L. , Sims J. L. , Wells K. L. 
Published: July 2010

AbstractExcessive Mo concentrations in forage crops have been reported to cause toxicity in livestock. Since forage crops often are grown following crops fertilized with Mo, a study was conducted to determine the effect of previous applications of Mo on Mo concentration and yield of dry matter of certain crop species. Five different crops were grown on Maury (Typic Paleudult; clayey, mixed, mesic) soil (pH 6.4) fertilized the previous year with levels of Mo (0, 0.22, 0.44, 0.88, 1.32, and 2.64 kg Mo/ha). The above‐ground plant parts were sampled at one or more dates, weighed, dried, and ground for Mo analysis.Generally, concentration of Mo increased as the level of Mo applied previously increased in all crops sampled and at most sampling dates. For crops sampled at two maturity dates, Mo concentrations were higher in plants sampled at the earlier date than when plants were mature. The lower values at mature harvest may be attributed to dilution by dry matter. Although concentrations increased with level of Mo applied, the highest concentration found (3.89 μg Mo/g dry weight) was judged unlikely to cause toxicity in livestock. Mo fertilization at recommended rates of soils with low‐to‐average Mo levels should not subsequently result in forage with Mo concentrations that are toxic to livestock. Mo fertilization had little effect on dry matter yields.
Rates of Photosynthesis and Transpiration and Diffusive Resistance of Six Grasses Grown Under Controlled Conditions1
Authors: Frank A. B. , Barker R. E. 
Published: July 2010

AbstractPhotosynthesis (Pn) and transpiration (E), and the components of diffusion resistance to CO2 and water vapor transport were measured in western wheatgrass (Agropyron smithii Rydb.), crested wheatgrass (A. desertorum [Fisch.] Schult.), pubescent wheatgrass (A. intermedium var. trichophorum [Link] Haloc.), Russian wildrye (Elymus junceus Fisch.), orchardgrass (Dactylis glomerata L.), and reed canarygrass (Phalaris arundinacea L.) to determine the rates of these processes and the role of stomates in controlling Pn and E. Plants were grown in a glasshouse and Pn and E measured at tillering and heading growth stages at three ambient CO2 concentrations and four light levels.At 1,160 μEm−2s‐−1 and 300 μl/liter CO2, Pn at tillering ranged from 10.2 to 26.2 mg CO2 dm−2hour−1 for reed canarygrass and western wheatgrass, respectively. E was lowest in reed canarygrass (1.1 g H2O dm−2hour−1) and highest in western wheatgrass (3.6 g H2O dm−2hour−1). Pn increased and E decreased for all species as ambient CO2 increased from 100 to 500 μl/liter CO2. Somate sensitivity to CO2 concentration and light level was evident in pubescent wheatgrass and orchardgrass but other species exhibited only slight changes. Minimum stomatal diffusion resistance to water vapor transport (rs) varied considerably among species. Partitioning of the components of resistance to CO2 and water vapor transport indicated that, at 1,160 μEm−2s−1 and 300 μ1/1 CO2, Pn of pubescent wheatgrass was primarily limited by stomatal apertures controlling diffusion of CO2 into the leaf (r's), whereas Pn of western and crested wheatgrasses, Russian wildrye, reed canarygrass, and possibly orchardgrass was limited more by the chemical process and/or internal resistances to CO2 diffusion in the liquid phase than by stomatal resistance. Ratios of E/Pn and rs/(r's+rm) (rm is mesophyll resistance), indicate that water use efficiency was highest in pubescent wheatgrass and lowest in western wheatgrass.
Budding Phenology of Guar in the Rolling Plains of Texas1
Authors: Rogers C. E. , Stafford R. E. 
Published: July 2010

AbstractDevelopment of a sound pest management program for the midge, Contarinia texana (Felt), requires a knowledge of the budding phenology of guar, Cyamopsis tetragonoloba (L.) Taub. Thus a 3‐year study was designed to determine the budding pattern for guar in the Rolling Plains of Texas. Guar was sampled and the number of floral buds counted weekly from the onset of budding until the plants reached maturity or were terminated by a freezing temperature.Bud production in guar under dryland cultivation was greatest in plants that emerged in mid‐June. With adequate soil moisture, three‐quarters of the total bud load in dryland guar was produced during the middle one‐third of the production period. Maximum bud production in dryland guar occurred during the 8th, 8th, 11th, and 16th week, respectively, for guar emerging on 25 May 1973, 12 July 1973, 12 July 1972, 15 June 1972 and 19 July 1974. Plants emerging on these dates produced 100, 50, 90 and 60% of the total bud load, respectively, by mid‐September.Bud production in irrigated guar was greatest in plants that emerged in mid‐to‐late May. Irrigated guar emerging on 22 May, 18 June, and 18 July, 1973, experienced maximum bud production during the eleventh, eighth, and sixth week postemergence, respectively. Plants emerging on these dates produced 90, 70, and 57% of the total buds, respectively, by mid‐September.This study indicates that for maximum returns for chemical control of the “guar midge,” treatment should be restricted to the middle one‐third of the budding season.
Alfalfa Weevil Effects on Root Reserves, Development Rate, and Canopy Structure of Alfalfa1
Authors: Fick Gary W. , Liu Beverly W. Y. 
Published: July 2010

AbstractDefoliation by the alfalfa weevil (Hypera postica Gyllenhal) results in a direct reduction in yield of alfalfa (Medicago sativa L.). Indirect responses to insect feeding may partially compensate for direct losses or cause further reductions in yield and feed quality. The purpose of this study was to identify indirect responses of alfalfa to weevil defoliation. We studied the effects of the alfalfa weevil on (i) root reserves, as measured by total nonstructural carbohydrates (TNC) in the taproot, (ii) morphological rate of development, and (iii) canopy structure.Alfalfa weevil defoliation produced statistically significant effects on all three factors. When the peak of the undisturbed larval population was about three/stem, TNC levels were reduced by up to 0.14 metric ton/ha while defoliation occurred. After the larval population declined, there was recovery growth and TNC yields reached levels up to 0.09 metric ton/ha higher than where weevils were controlled. The crossover from lower to higher TNC levels was associated with delayed morphological development and a prolonged TNC accumulation period where damage occurred. When alfalfa was cut before the larval population reached a peak, TNC levels were reduced during the regrowth period. Larval populations higher than two/stem reduced canopy height and leaf percentages during defoliation. During the post‐defoliation recovery period, moderately damaged plants increased in leaf percentage and produced more branches than lightly defoliated plants. However, the moderately defoliated plants remained shorter and there were resulting large differences in canopy structure. These findings showed a wide range of indirect effects of insect defoliation on alfalfa growth, and they should be considered in evaluating insect damage to the crop.
Growth Rate and Nutrient Uptake of Two Cotton Cultivars Grown Under Irrigation1
Authors: Halevy J. 
Published: July 2010

AbstractThe production of high cotton yield is highly dependent on adequate growth rate and nutrient uptake about which relatively little information is available under semiarid conditions. Growth rate and N, P, K uptake of two cotton (Gossypium hirsutum L.) cultivars, ‘Acala 1517‐C’ and ‘Acala 4‐42,’ which differ in their response to K fertilizer, were investigated in an irrigated field (soil type ‐ Typic Rhodoxeralf) under favorable conditions conducive to high yields.The rate of dry matter production was slow until flowering and after the first bolls opened. Up to 72 days from emergence, 15% of the total dry matter was produced; from 112 days until picking, 10%; and during the 40‐day period from 72 to 112 days, 75%. Throughout this period the growth rate was nearly linear, 250 kg/ ha/day.Total dry matter was 12,200 to 13,480 kg/ha. Its distribution in mature plants was 26% in the leaves, 24% in stems, 16% in burs, 21% in seeds, and 13% in lint. The lint yield was 1,700 kg/ha. Total uptake of N, P, and K was 230, 45, and 174 kg/ha.The total uptake of N and P followed that of dry matter production, whereas K was absorbed more rapidly, reaching a maximum at 112 days from emergence and then decreasing. The removal of nutrients from the field by seed and lint was 98 to 109 kg N/ha, 19 to 21 kg P/ha, and 43 to 47 kg K/ha.Toward the end of growing season Acala 1517‐C suffered more than Acala 4‐42 from K deficiency in soils with a low supply of available K. The factors which may be responsible for this in Acala 1517‐C are earlier development, greater uptake of K during early growth, the larger uptake of K by relatively more developed reproductive parts, and the relatively smaller root system.The rates of growth and uptake in the present experiment were greater than those reported in the literature. Also, Acala 1517‐C and Acala 4‐42 differed in their nutrient uptake, especially of potassium.
Stomatal Response to Leaf Water Potential as Affected by Preconditioning Water Stress in the Field1
Authors: Thomas J. C. , Brown K. W. , Jordan W. R. 
Published: July 2010

AbstractPrevious research has shown that stomatal response to decreasing soil water potential of chamber‐grown sorghum (Sorghum bicolor L. Moench. ‘Oro’) and cotton (Gossypium hirsutum L. ‘Stoneville 213’) is altered by exposure to previous water stress. This work was undertaken to determine if stomatal response of field‐grown plants is also altered by previous water stress.Stoneville 213 cotton was grown in the field under movable rainshelters and was subjected to three treatments: control — well watered, one period of water stress, and two periods of water stress. After this preconditioning period, all plants underwent a final stress during which stomatal response to leaf water potential was measured.The periods of preconditioning water stress were characterized by decreased cumulative growth as measured by leaf area per plant. Leaf areas for the control, one soil water stress plants, and two soil water stress plants were 5,200, 2,200, and 1,200 cm2, respectively. Lower stomates of preconditoned field‐grown plants remained open to lower leaf water potentials (—28 to —30 bars) during the final stress than those of plants which were not preconditioned (—22 bars). These results were similar to those found previously on chamber‐grown plants which had been exposed to more frequent but shorter stresses. The 6 to 8 bar adjustment in leaf water potential vs. stomatal resistance as a result of previous water stress indicates a need for caution in interpreting data from plants of unknown water stress history.
Effect of Soil Moisture Tension and Amendments on Yields and on Herbage N, P, and S Concentrations of Alfalfa1
Authors: Nuttall W. F. 
Published: July 2010

AbstractLow protein concentration has been observed in alfalfa herbage grown on Gray Wooded Luvisol soils, particularly in cool, wet years. Nutrient deficiencies of N, P, and S also occur on these soils. The objectives of this experiment were to determine how soil moisture and soil type interact with amendments to increase yield and change N, P, and S concentrations in alfalfa (Medicago media Pers.) herbage grown in the greenhouse.Three Gray Wooded Luvisols, Typic Cryoboralf (Arborfield clay, Garrick clay loam, Mollic Cryoboralf, and Waitville loam) and one Dark Gray Luvisol soil (Nipawin sandy clay loam) × two soil moisture tensions (100 and 151 millibars) were main treatments. Amendments of cattle manure, sedge peat, and wheat straw were applied on subplots at 2.5y0 of soil weight. Additional subplots of a control and nitrate (70 μg N/g soil before each crop) were added. Two crops of barley (Hordeum vulgare L.) and one of rape (Brassica napus L.) were grown before ‘Rambler’ alfalfa.Yield of alfalfa was significantly related to moisture use (r2 = 77% in cut 1; r2 = 78% in cut 2). Moisture use by alfalfa was higher with cattle manure incorporated in the heavier textured Garrick clay loam and Arborfield clay soils than for other amendments or soil types. The manure treatment applied to Garrick clay loam and Arborfield clay soils under low soil moisture tension (LSMT = 100 millibars) produced the highest herbage yields.In the first‐cut only, N concentration of alfalfa herbage was higher under high soil moisture tension (HSMT = 151 millibars) than LSMT (5.0 vs. 4.8% N) and was higher for ammonium nitrate than for manure or peat amended soils. Concentration of P in alfalfa herbage was significantly higher under LSMT than HSMT. Concentration of S in herbage was significantly lower under LSMT than under HSMT only for cut 1.In general, LSMT interacting with soil type and amendments markedly increased alfalfa yields, reduced N and S, and increased P concentration in herbage as compared with HSMT.
Critical Ca Levels and Ca/Mg Ratios in Trifolium subterraneum L. Grown on Serpentine Soil1
Authors: Jones M. B. , Vaughn C. E. , Harris R. S. 
Published: July 2010

AbstractSerpentine soils are known to have a low Ca/Mg ratio and to respond to applied Ca in many instances. To assist in assaying the Ca status of these soils we determined the effect of growth stage, plant part, and defoliation treatment on the critical Ca concentrations and Ca/Mg ratios in subclover growing in potted serpentine soil of the Henneke series, a lithic Argixeroll.One of six rates (0, 200, 400, 800, 1,600, and 3,200 ppm) of Ca as CaSO4 and uniform rates of P, K, S, and Mo were applied to each pot and the soil was mixed uniformly and planted to ‘Geraldton’ subclover (Trifolium subterraneum L.). On one set, leaves were removed 61, 85, and 114 days after planting. On a second set, leaves were removed on days 85 and 114, and the third set grew without clipping until day 114.Critical Ca percentages in the three youngest leaves ranged from 0.55 to 0.69%, with no consistent trend due to growth stage or number of times the plant had been defoliated. In old leaves, critical Ca levels ranged from 0.81 to 1.47% and were higher for 114‐day‐old plants than for 85‐day‐old plants. The more often the plant was defoliated the lower the critical Ca level in old leaves. There was no significant difference between young and old stem tissue in critical Ca levels: 0.30 to 0.38% Ca. Defoliation did not induce a consistent change.Critical Ca/Mg ratios in young leaves increased from 0.42 to 0.60 between plant ages of 61 and 85 days, whereas no significant change occurred from day 85 to 114. With plants defoliated for the third time at day 114 the critical Ca/Mg ratio was 0.36, although at the first and second clippings their critical ratios were 0.60. Calcium/Mg ratios were similar in young and old leaves. In young stems the critical Ca/Mg ratios on day 114 for the first, second, and third clippings were respectively 0.48, 0.39, and 0.21. The same values for old stem tissue were 0.38, 0.27, and 0.18.It was concluded that percent Ca and Ca/Mg ratios in new and old stems were insensitive as measures of Ca status since these values changed less in stem than in leaves over a wide range of Ca levels. Percent Ca in young leaves was the best measure of Ca status because critical values varied less due to stage of growth or clipping treatment than did percent Ca in old leaves or Ca/Mg ratios in young or old leaves.
Response of 21 Oat Cultivars to Nitrogen Fertilization1
Authors: Ohm H. W. 
Published: July 2010

AbstractThe importance of percent protein in oats (Avena sativa L.) as a food and feed grain has resulted in the recent development of cultivars with an inherently high percent of groat protein. The need to determine the effects of N fertilization as an additional means of increasing the percent protein prompted experiments to determine responses to fertilizer N of 21 oat cultivars differing widely in percent groat protein and several agronomic traits. Two N treatments: one, no added N (40 to 50 kg available N/ha in the soil); and two, 110 kg N/ha in a split application were assigned at random to main plots. The 21 cultivars (19 of A. sativa and 2 of A. sativa × Avena sterilis L.) were assigned at random to subplots.Application of N resulted in significant increases in plant height, lodging score, percent protein, and yield; it did not affect heading date or seed weight; and it reduced test weight. Short‐strawed types increased in plant height more with N application than several taller cultivars although plant height increases were greatest for other tall types. Lodging scores of weaker strawed cultivars did not always increase more with N application than those of stronger strawed cultivars. Percent protein in certain low protein cultivars increased more than that of some high protein cultivars with fertilizer N. A given cultivar may not respond similarly to N for percent protein and/or yield.More extensive testing of potential new cultivars to determine specific fertility × cultivar interactions is recommended.
Differential Tolerances of Triticale, Wheat, Rye, and Barley to Aluminum in Nutrient Solution1
Authors: Mugwira L. M. , Elgawhary S. M. , Patel K. I. 
Published: July 2010

AbstractAluminum toxicity to cereals is an important consideration when adapting a new crop to the acid soils of the Southeast. The objective of this study was to evaluate the relative tolerances of different cultivars of triticale (X Triticosecale) a new crop, wheat (Triticum aestivum L.), rye (Secale cereale L.), and barley (Hordeum vulgare L.) to Al in nutrient solution with a pH of 4.8 at the time of transplanting. Plant induced pH change in the nutrient solution and dry matter produced were used as criteria for evaluating Al tolerance. Triticale resembled the other three species in increasing the pH of the solution during growth when no Al was added to the nutrient solution. When 6 ppm Al was added, triticale ‘6TA 131’ and ‘6TA 298,’ Al‐tolerant ‘Thorne’ and ‘Seneca’ wheats, and ‘Vitagraze’ rye increased the nutrient solution pH to values higher than 5.0. However, triticales ‘6TA 385,’ ‘6TA 203,’ and 6TA 522,’ the different barley cultivars, and ‘Abruzzi’ rye either decreased or had no effect on solution pH. ‘Atlas 66’ wheat induced significantly higher pH at 6 ppm Al added to the medium than all the other cultivars tested.The addition of 6 ppm Al to the nutrient solution reduced the shoot growth of the different cultivars generally in a similar manner. However, reductions in root dry matter by Al indicated that, on the average, Al tolerances were: Al‐tolerant wheat and rye > triticale and Al‐tolerant barley > Al‐sensitive barley and Al‐sensitive wheat. The pH changes induced by the plants in the solution with 6 ppm Al generally confirmed the same order of tolerance as obtained from reductions in root dry matter. Increasing Al in solution significantly increased Al but decreased Ca and P in triticale, wheat, and rye. Aluminum‐sensitive wheat contained higher Al in roots than Al‐tolerant wheat. The roots of triticale and rye cultivars significantly differed in Al concentration.
Leaf Conductance Response to Humidity and Water Transport in Plants1
Authors: Hall Anthony E. , Hoffman Glenn J. 
Published: July 2010

AbstractStomatal response to humidity is a potentially important adaptive characteristic. The possibility that stomata may respond to humidity independently of changes in bulk leaf water status was tested. Also the basis for reported differences in leaf water potential response to transpiration was investigated.Simultaneous measurements of in situ leaf water potential, transpiration, and net photosynthesis were made in controlled environments using sunflower (Helianthus annuus L.) and pinto bean (Phaseolus vulgaris L.). Responses of leaf conductance and leaf water potential to changes in ambient humidity and root medium water potential were determined.Leaf conductance responded consistently to changes in the vapor pressure difference between leaf and air. Decreases in ambient humidity resulted in decreases in leaf conductance with constant, decreasing or increasing leaf water potentials. Leaf conductance responded to changes in leaf water potential only when manipulations of plant water supply resulted in rapid decreases in leaf water potential below a threshold level of —8 bars. These data demonstrate that stomata may respond to humidity independently of changes in leaf water potential.On occasions environmental perturbations resulted in changes in leaf water potential that were negatively correlated with changes in transpiration. On other occasions leaf water potential remained constant when transpiration rate or water potential of the root medium was changed. On one occasion an inverted water potential gradient between root medium and leaves was observed in a transpiring plant. Models of the simultaneous movement of water and solutes within plant roots provided qualitative explanations for these observations by predicting that changes in the uptake and translocation of solutes may influence leaf water potential response to transpiration.
Photosynthate Distribution in Natural Stands of Salt Water Cordgrass1
Authors: Hull R. J. , Sullivan D. M. , Lytle R. W. 
Published: July 2010

AbstractSpartina alterniflora Loisel. is a major grass species of Atlantic coast tidal marshes which contributes heavily to the primary productivity of estuarine ecosystems. As human activity increases in marsh areas, the capability of marsh vegetation to withstand disturbance must be understood and constitute the basis for formulating sound management programs. Toward this end, the seasonal distribution of photoassimilated carbon was studied in S. alterniflora growing under natural conditions. Single culms were exposed to 14CO2 at various times during the 1970 and 1971 growing seasons. Plants were harvested 1, 3, and 7 days following exposure to 14CO2. subdivided into leaves, culm, rhizomes, and roots; and each portion assayed for 14C. Assimilate translocation reached a more or less stable distribution pattern within 24 hours. Throughout much of the growing season, most photosynthate was retained in leaf and culm tissue with less than 10% translocated to roots and rhizomes. Only during early autumn was substantial photosynthate translocated into rhizomes. This and seasonal carbohydrate levels within perennial organs indicate that the stability of S. alterniflora stands may be adversely affected by summer disturbance especially defoliation.
Influence of Various Row Widths on Yields and Agronomic Characteristics of Proso Millet1
Authors: Nelson L. A. 
Published: July 2010

AbstractSeveral varieties of proso millet (Panicum miliaceum L.) were tested in five environments at 18‐, 36‐, 53‐, and 71‐cm row spacings on typic argustoll soils. The objectives of the tests were to determine the influence of row spacing on several agronomic traits of proso and to detect any row spacing by variety interaction influence on these traits which would indicate the importance of testing varieties at the same row spacing as the producers use.Yields were highest with 18‐cm spacings and lowest with 71‐cm spacings. Each additional 18 cm in row width reduced yield 220 kg/ha. Only one environment caused a significant yield change due to variety by row spacing interaction. Plants responded to wider row spacing by increasing in height and decreasing slightly in the time to heading.Higher plant populations within a row at a wide row spacing reduced the proportion of planted seed which survived. Results of these tests indicate that variety testing should be conducted at a row spacing similar to that used for production of proso and that a producer should consider buying a drill with a narrow row spacing for the production of proso.