bluuebunny/crossref_metadata_2025_split huggingface dataset:
Plant Water Relations, Photosynthesis, and Rubber Content of Young Guayule Plants during Water Stress1
Authors: Allen S. G. , Nakayama F. S. , Dierig D. A. , Rasnick B. A. 
Published: July 2010

AbstractGuayule (Parthenium argentatum Gray, cv. N565 II), a drought tolerant, rubber‐producing shrub native to the desert Southwest, was grown in field plots at Phoenix, AZ, in an Avondale loam soil [fine, loamy, mixed (calcareous), hyperthermic Typic Torrifluvent] in well‐watered and drought conditions. The purpose of the investigation was to characterize the relationships between plant water relations, photosynthesis, and rubber content during drought stress to improve water management practices. The drought treatment lasted 70 days (29 May–5 Aug. 1986) during which the soil moisture content gradually declined from 340 to 165 mm in the top 1.1 m of soil. The well‐watered plots were maintained at greater than 260 mm soil moisture per 1.1 m of soil. Values for psychrometric measurement of water potential of the stressed plants declined to −3.0 MPa, 1.2 MPa less than the well‐watered plants, while maintaining approximately equal and positive pressure potential. This suggests an important role for osmotic adjustment in the drought tolerance of guayule. Net photosynthesis in both treatments steadily declined from about 10.0 to 3.5 µMol m−2 s−1 during the experiment, but with no apparent inhibition due to drought stress. Rubber content increased over fivefold in the stressed plants (from 0.4 to 2.1%) and doubled in the well‐watered plants (from 0.4 to 0.8%) over the course of the experiment. However, the stress treatment reduced final plant size, based on plant height and width measurements, by approximately one‐third compared to the well‐watered treatment. Controlled periods of stress should be investigated as a potential management tool to increase rubber content as well as reduce irrigation water requirements.
Tolerance of Perennial Ryegrass and Tall Fescue Seedlings to Fenoxaprop1
Authors: Dernoeden Peter H. 
Published: July 2010

AbstractSummer annual grass weed competition can limit successful spring or summer establishment of cool‐season grasses. Fenoxaprop [(±)‐ethyl 2‐{4‐[(6‐chloro‐2‐benzoxazolyl) oxy]phenoxy}propanoate] is an effective postemergence summer annual graminicide that is safe to use on mature stands of perennial ryegrass (Lolium perenne L.) and tall fescue (Festuca arundinacea Schreb.). Field studies were conducted to determine the tolerance of perennial ryegrass and tall fescue seedlings to fenoxaprop and to assess fall turfgrass cover of the aforementioned species grown in competition with smooth crabgrass [Digitaria ischaemum (Schreb.) Muhl.]. Separate areas of ‘Citation’ and ‘Palmer’ perennial ryegrass and ‘Olympic’ and ‘Houndog’ tall fescue were seeded on either a Chillum silt loam (fine‐silty, mixed, mesic Typic Hapludults) or a Beltsville silt loam (fine‐loamy, mixed mesic Typic Fragiudults). Fenoxaprop caused seedling yellowing of both species on one of six application dates over a 2‐yr period. No stand reduction or other adverse visual effects from any fenoxaprop treatment (0.09–0.28 kg ha−1) were observed. Fenoxaprop applied at 0.09 kg ha−1 effectively controlled (>90%) one‐ to 3‐leaf stage smooth crabgrass, but 0.28 kg ha−1 were required to effectively control two‐ to four‐tiller stage smooth crabgrass. Single applications of fenoxaprop at all rates and dates of application were sufficient to reduce smooth crabgrass competition and insure good (89%) to excellent (99%) turfgrass cover.
Root Morphology and Vigor Effects on Winter Heaving of Established Alfalfa1
Authors: Perfect E. , Miller R. D. , Burton B. 
Published: July 2010

AbstractThere has been considerable speculation regarding the influence of root system morphology on the susceptibility of alfalfa (Medicago sativa L.) to frost heaving injury. This field study represents a first attempt at quantification of that relationship. A tagging technique was developed for monitoring heave of established alfalfa plants during winter. Measurements were made on a Collamer silt loam (Glossoboric Hapludalf) intergrading to a Niagara silt loam (Aeric Ochraqualf) near Ithaca, NY. Final (net) crown displacement above the soil surface was positively correlated with plant upheaval in midwinter, although maximal uplift was partially reversed as the soil thawed. Plants were retrieved after the winter and evaluated for differences in vigor and taproot architecture. Under comparable soil heaving conditions, 2‐yr‐old plants with the creeping root trait experienced a mean net uplift of 5.5±1.1 mm compared to 8.5±1.2 mm for plants with a pronounced taproot; this difference was significant at P < 0.06. In contrast, spatial variation in maximum soil heave was more important than root morphological parameters in determining uplift of 3‐yr‐old plants from a single taprooted cultivar. Only 45% of the total variance in maximal crown displacement could be explained by multiple regression analysis, suggesting that undefined variables, such as root anchorage and tissue elasticity, may be involved. Approximately 60% of the taproots appeared to have heave related lesions. The vigor of these mature plants was generally unrelated to frost heaving; net upheaval was correlated with the degree of crown rot, but not with root rot, number of crown buds, or curculio (Sitona hispidula F.) scarring.
Indeterminate and Determinate Soybean Responses to Planting Date1
Authors: Wilcox J. R. , Frankenberger E. M. 
Published: July 2010

AbstractDeterminate and indeterminate soybean [Glycine max (L.) Merr.] strains respond differently to planting date in the northern United States. The objectives of this study were to compare performance of closely related determinate and indeterminate strains in response to planting date. Five pairs of determinate and indeterminate isolines or related cultivars were evaluated at three planting dates for 1 yr, and five planting dates for two succeeding years at West Lafayette, IN. Dates were recorded when plants reached stages V1 to V5 and all reproductive stages. Additional data were recorded on agronomic characteristics of the isolines. Planting delays resulted in fewer days between stages V1 to V5 in 2 of the 3 yr and in stages R2 through R8 in all 3 yr. Determinate and indeterminate strains responded the same to planting delays in the vegetative stages V1 to V5 but not in the reproductive stages. Indeterminate strains were shorter and had fewer nodes with planting dates after May 24. Determinate strains either increased or were the same in plant height and number of nodes with successive planting dates after May 24. When lodging was moderate to severe, strains of both types lodged more severely when planted in June than in May. In general, determinate strains yielded more when planted late May or early June; indeterminate strains produced maximum yields when planted from early to late May. Determinate strains responded similarly to planting date regardless of the source of the dt1 gene.
Effects of Nitrogen Fertilization on a Chinese Cabbage Hybrid
Authors: Guillard K. , Allinson D. W. 
Published: July 2010

AbstractBrassica spp. may be used advantageously during forage‐deficit periods, particularly for late‐season grazing in the northern USA. This study evaluated the influence of N fertilization on the yield and N metabolism and distribution in ‘Tyfon’ [B. rapa L. × B. pekinensis (Lour.) Rupr.], a Chinese cabbage hybrid. Field experiments were conducted in August through November of 1983 and 1984 on a Woodbridge fine sandy loam soil (coarse‐loamy, mixed, mesic Aquic Dystrochrept). Tyfon was no‐till seeded into a herbicide‐suppressed sod, followed by broadcast N at rates of 0, 56,112,168, and 224 kg ha−1. Foliage yields, N uptake, and concentrations of total N and NO3−N increased with applied N. Root yields, concentrations of dry matter, and N use efficiencies were reduced as N rate increased. The amount of N partitioned into the foliage was much greater than in the roots. Once total N uptake reached approximately 100 kg ha−1, no significant increases in yield were observed. Total N recovery, averaged over years, exceeded 75% at the 56 to 168 kg N ha−1 treatments. These data suggest that N fertilization of Tyfon is beneficial only when the amount of N available to plants results in N uptakes of less than 100 kg ha−1. Excessive N fertilization is accompanied by accumulation of NO3–N in the plant.
Timing and Intensity of Water Deficits During Flowering and Grain‐Filling in Pearl Millet
Authors: Mahalakshmi V. , Bidinger F. R. , Rao G. D. P. 
Published: July 2010

AbstractYields of pearl millet [Pennisetum americanum (L.) Leeke]–a rainfed crop grown mainly on light soils in the semiarid and arid regions–are often reduced by water deficit when rains end early. The comparative response of this crop to varying intensity and timing of water deficit during flowering and grain‐filling was investigated in field experiments using a line‐source sprinkler system. The soil was an Alfisol (Udic Rhodustalf) with approximately 60 mm of plantextractable moisture. Genotypes differing in maturity were used to simulate differing timings of terminal stress. Grain yields were linearly reduced with increasing intensity of stress in all genotypes. Yield reduction rate was dependent on the time of stress onset in relation to time of flowering, as earlier‐flowering genotypes partially escaped stress. Grain number per unit area and grain size were reduced by intensity of water deficit. Grain yield and grain number, but not grain size, were affected by the time of stress onset at all intensities. Across the entire data set, stress intensity and timing accounted for 75% of the variation in measured grain yield. An advance in time of onset of stress by a day caused a 0.9% reduction in relative grain yield, compared to a 0.7% reduction in relative grain yield for each 1% additional irrigation deficit. Effects of timing of stress increased significantly with increase in stress intensity. The results emphasize the importance of timing and intensity of stress when comparing genotypes of different maturity groups using linesource gradient system, or when selecting genotypes for droughtprone environments
Short‐Term Crop Rotation Systems for Soybean Production
Authors: Dabney S. M. , McGawley E. C. , Boethel D. J. , Berger D. A. 
Published: July 2010

AbstractContinuous monocrop soybean [Glycine max (L.) Merr.] production has been common in Louisiana for 20 yr. This field study was undertaken to determine if, and how, short‐term crop rotations could increase soybean yield on a Providence silt loam (fine‐silty, mixed, thermic Typic Fragiudalfs) in southeast Louisiana. Eight 2‐yr rotations were evaluated in a field following 15 yr of continuous soybean production. Rotations investigated were: continuous soybean; soybean rotated with grain sorghum (Sorghum bicolor L.); soybean rotated with fallow; soybean doublecropped with winter wheat (Triticum aestivum L.); soybean alternated with winter wheat underseeded with alfalfa (Medicago sativa L.); and three additional rotations, identical to the first three listed with the addition of a winter ryegrass (Lolium multiflorum L.) cover crop. Two soybean cultivars, Centennial and Davis, with different plant parasitic nematode susceptibility, were evaluated in each rotation. Over four complete rotation cycles, Centennial consistently out‐yielded Davis. Soybean grown after either grain sorghum or fallow consistently out‐yielded soybean grown following soybean. This difference existed during favorable and unfavorable growing seasons and was greater for Davis than for Centennial. Insect populations were not high at the study site and did not have a major impact on crop yields. Soybean cyst nematode (Heterodera glycines Inchinohe) populations were higher under Davis than Centennial soybean, increased each year, and were greater with continuous soybean than with rotation. Control of cyst nematode populations appeared to be the main reason for the beneficial rotation effect observed in this study.
Aerial Accumulation and Partitioning of Nutrients by Corn
Authors: Karlen D. L. , Flannery R. L. , Sadler E. J. 
Published: July 2010

AbstractAmounts and rates of dry matter and nutrient accumulation for very high‐yielding corn (Zea mays L.) were unknown, but were needed to develop a base for future research and on‐farm maximum economic yield demonstration programs. Aerial whole plant samples, collected from a maximum yield research experiment that resulted in a 19.3 Mg ha−1 grain yield on a Typic Hapludult soil (Freehold sandy loam) near Adelphia, NJ, were used to provide that information. Samples were collected at growth stages V4, V8, V12, VT, R1, R2, R5, and R6; separated into lower leaves, upper leaves, stem and tassel, and ear and shank fractions; and analyzed to determine N, P, K, Ca, Mg, S, B, Cu, Fe, Mn, and Zn concentrations. Accumulation curves for each plant fraction were computed using those data and described mathematically using compound cubic polynomial equations. Dry matter and nutrient accumulation rates were computed by differentiating the equations. Total accumulation at physiological maturity was approximately 31 800, 386, 70, 370, 59, 44, 40, 0.13, 0.14, 1.9, 0.9, and 0.8 kg ha−1 for dry matter, N, P, K, Ca, Mg, S, B, Cu, Fe, Mn, and Zn, respectively. Distribution among the four plant fractions, as well as rates of accumulation, are discussed. Diagnosis and recommendation integrated system indices were calculated using leaf concentration data. Nutrient balance was very good, although fertilizer recovery was not optimum. Amounts and rates of accumulation measured in this study can provide general guidelines for very high corn yields when more economical practices are used.
Grass Seedling Emergence, Morphology, and Establishment as Affected by Planting Depth
Authors: Newman P. R. , Moser L. E. 
Published: July 2010

AbstractThe seeding depth of grasses affects emergence and adventitious root development. Seedling root morphology and development should be considered when determining planting depth for forage grasses. A field study was conducted on a Kennebec silt loam (fine‐silty, mixed, mesic Cumulic Hapludolls) during June to August 1985 and 1986 to investigate the effect of planting depth on seedling emergence, morphology, and establishment of smooth bromegrass (Bromus inermis Leyss.), big bluestem (Andropogon gerardii var. gerardii Vitman), indiangrass [Sorghastrum nutans (L.) Nash], and switchgrass (Panicum virgatum L.). Seeds were planted by hand to insure seeding depths of 1.5, 3.0, 4.5, and 6.0 cm. Emergence percentage decreased with increased planting depth for all grasses except switchgrass, which had similar percentages at the 1.5‐ and 3.0‐cm planting depths. Coleoptile length and seedling crown depth were positively correlated with actual planting depth in smooth bromegrass, while subcoleoptile internode length was positively correlated with actual planting depth in big bluestem, indiangrass, and switchgrass. Indiangrass differed from big bluestem and switchgrass, since its coleoptile length was positively correlated with actual planting depth. Smooth bromegrass may have the potential of increased adventitious root development due to deep placement of the seedling crown in the soil. Big bluestem, indiangrass, and switchgrass do not have the potential of increased adventitious root development as seeding depth increases, since there was no correlation of seedling crown depth with actual planting depth. Rapid increase in adventitious root number of big bluestem, indiangrass, and switchgrass was noted after three or more consecutive days of rainfall after 4 wk from planting.
Effect of Water Deficit at Different Growth Phases of Peanut. II. Response to Drought During Preflowering Phase
Authors: Rao R. C. Nageswara , Williams J. H. , Sivakumar M. V. K. , Wadia K. D. R. 
Published: July 2010

AbstractWater deficits can affect peanut yields differentially depending on time of occurrence and intensity. Previous reports have shown that moderate water deficit during the preflowering phase increases pod yields by 13 to 19% relative to the fully irrigated control. This paper describes, in a more quantitative way, crop physiological factors that contribute to these increased yields. In the 1980 to 1981 and 1981 to 1982 postrainy seasons, a study was conducted on a medium deep Alfisol at the International Crop Research Institute for the Semi‐Arid Tropics (ICRISAT) in central India, to examine the responses of peanut (Arachis hypogaea L.), cv. Robut 33‐1, under three levels of soil water deficits during preflowering phase relative to an adequately irrigated control. Three intensities of drought were created (from 10–50 d after sowing [DAS]) using‐line source sprinkler irrigation, while the control was irrigated at 10‐d intervals. Moderate water deficits during the preflowering phase increased subsequent crop growth and pod growth rates in 1980 to 1981 but not in 1981 to 1982. Differences in flowering and total pod numbers between treatments were relatively small when compared to the subsequent differences in pod setting and maturity. In both seasons, greater synchrony of pod set in the moderately stressed plots resulted in a greater proportion of mature pods at final harvest. The most severely stressed plot had lower yields despite adequate irrigation subsequent to the preflowering water deficits.
Irrigation Water Management for Guar Seed Production
Authors: Alexander W. L. , Bucks D. A. , Backhaus R. A. 
Published: July 2010

AbstractAgricultural crops with low water requirements and drought tolerance are needed for semiarid irrigation regions. Guar [Cyamopsis tetragonoloba (L.) Taub.] is promising as a crop for producing food‐thickening agents and fluid additives for the oil drilling industry. The effects of irrigation timing, cultivar, and plant population on water use, growth, and yield of guar were investigated at Maricopa, AZ, on a Mohall sandy loam soil (fine‐loamy, mixed, hyperthermic Typic Haplargid) with a water salinity of 1.1 dS m−1 total dissolved salts over a 2‐yr period. Variables were: six irrigation levels (one to four irrigations based on physiological plant growth stages), three cultivars (‘Kinman’, ‘Santa Cruz’, and ‘Lewis’), and three populations (78, 26, and 13 plants m−2). Three post‐establishment irrigations—one before flowering, one during initial pod development, and one at mid‐pod filling—were optimal. Four irrigations maximized vegetative growth but reduced seed production per unit of water use; two irrigations lowered growth, seed yield, and water use efficiency. Seed yields averaged 1567, 1650, and 1830 kg ha−1 for Kinman, Santa Cruz, and Lewis, respectively. Seasonal evapotranspiration was 400 mm on the optimal seed production treatments, and water use efficiencies were as high as 0.64 kg seed m−3 in 1983, and 0.41 kg seed m−3 in 1984. The newer Lewis has the potential for higher yields, in addition to being an attractive, low water‐use summer crop for the southwestern United States.
Efficiency of Maize Dry Matter Production During Periods of Complete Leaf Area Expansion
Authors: Tollenaar M. , Bruulsema T. W. 
Published: July 2010

AbstractCrop dry matter production, in the absence of other limiting factors, is determined by the absorption of photosynthetically active radiation (PAR) by a crop canopy and the efficiency with which absorbed PAR is converted into dry matter. This study was conducted to investigate the effects of plant density and phase of development on PAR absorption and conversion efficiency of two maize (Zea mays L.) hybrids. The maize hybrids Pioneer 3851 and Pioneer 3925 were grown in 1984 and 1985 at plant densities of 3.9, 6, and 10 plants m−2 in irrigated field experiments near Elora, Ontario, on a London loam (Aquic Hapludalf) soil that had been systematically tile drained. Conversion efficiency was estimated from rates of aboveground dry matter accumulation and PAR absorption from approximately 2 wk before to 6 wk after silking. PAR absorption was estimated from continuous measurements of incident PAR, PAR reflectance and PAR transmittance. Crop growth rates declined during the phase of development under study due to a decline in incident PAR and a decline in conversion efficiency from 5.8 to 3.5%; PAR absorptance was approximately 89% and remained fairly stable. Leaf area index among density‐hybrid treatments ranged from 2.0 to 4.8, and PAR absorption of the latter was 9% higher than that of the former. Although crop growth rates of the plant densities were not different during the grain‐filling period, differences in PAR absorption were too small to show a significant effect of plant density on conversion efficiency. Photosynthetic conversion efficiency appears to be influenced by phase of development, but the effects of plant density on efficiency appear to be small.
Long‐Term Tillage and Rotation Effects on Corn Growth and Yield on High and Low Organic Matter, Poorly Drained Soils
Authors: Griffith D. R. , Kladivko E. J. , Mannering J. V. , West T. D. , Parsons S. D. 
Published: July 2010

AbstractLittle information is available that evaluates long‐term use of a range of tillage systems and different cropping sequences on poorly drained soils. This study relates corn (Zea mays L.) growth and yield to several reduced tillage systems used with continuous cropping and a corn‐soybean (Glycine max L.) rotation. Experiments were conducted on Chalmers silty clay loam (fine‐silty, mixed, mesic Typic Haplaquoll) with 40 g kg−1 organic matter for 12 yr, and Clermont silt loam (fine‐silty, mixed, mesic Typic Ochraqualf) with 10 g kg−1 organic matter for 7 yr. Both soils are nearly level and poorly drained. Tillage systems compared included moldboard plowing, chisel plowing, ridge planting, and no‐till planting. Shallow disking (10 cm) was also included at the Clermont site. On the high organic matter Chalmers soil, continuous no‐till corn was 25 cm shorter at 8 wk, 2% wetter at harvest, and 9.2% lower in yield compared to plowing. Data for chisel and ridge systems were intermediate between plowing and no‐till. No‐till yields were consistently lower than those for plowing after the first 4 yr. When following soybean, no‐till corn was 7 cm shorter at 8 wk, 1% wetter at harvest, and 2.6% lower in yield than corn under moldboard plowing. Corn growth and yield from chisel and ridge treatments were equal to those with plowing when in rotation. On the low organic matter soil in continuous notill corn, plant growth and yields were reduced for the first 3 yr, but were equal or better, compared to plowed corn, for the final 4 yr. In rotation, no‐till corn was equal to plowed corn the first 3 yr and significantly better in 3 of the last 4 yr. Yields with intermediate tillage were similar to plowed yields for continuous and rotational cropping. The relative advantage for no‐till planting with time on the low organic matter soil is attributed to improved soil physical properties.