bluuebunny/crossref_metadata_2025_split huggingface dataset:
Corn Leaf Area Response to Early‐Season Soil Temperature under Crop Residues
Authors: Fortin M. ‐C. , Pierce F. J. , Edwards M. 
Published: July 2010

AbstractResidue cover from conservation tillage modifies the soil temperature regime, compared with conventional tillage. This study was conducted to examine the influence of crop residue on the area of corn (Zea mays L.) leaves developed when the apical meristem is below the soil surface. Field studies compared the effects of residue‐covered and bare soil (Conover loam in East Lansing MI in 1988 and Brookston clay in Woodlsee, ON, in 1990), on maximum area per leaf (LAmax) at V6 and on leaf area index (LAI) after silking. LAmax for Leaves 4 to 6 was 11 to 52% higher in plants grown in residue‐covered soil than in bare soil. LAI after silking was similar in both treatments. LAmax differences could not be related to differences in volumetric water content or N concentration. Thermal effects of crop residue on LAmax and leaf appearance rates were tested in growth chamber. After emergence, the corn apical meristem was exposed to air. Nighttime air temperatures were maintained at 16°C and daytime air temperatures were controlled at 18, 21, and 25°C, simulating seed zone temperatures measured in the field. Daytime air temperatures of 21°C resulted in higher LAmax for Leaves 4 to 6 on V6 plants than did 18 or 25°C. Appearance rates increased with temperature. These results suggest that seed zone temperature under residue from emergence to V6 (≈23°C) was more favorable for LAmax than seed zone temperature under bare soil (≈26°C). Thus, for corn Leaves 4 to 6 the temperature optimum for LAmax is lower than the temperature optimum for leaf development.
A Colorimetric Method for Assaying Dissolved Oxygen Loss from Container‐Grown Rice Roots
Authors: Kludze H. K. , DeLaune R. D. , Patrick W. H. 
Published: July 2010

AbstractAlthough not easily measured measured, oxygen release from rice (Oryza sativa L.) roots determines the plant's ability to survive reducing conditions. Our main objective was to test titanium‐citrate complex for its potential to quantify dissolved O2 concentrations in solutions bathing the whole root system of container‐grown rice cultivars. Influences of aeration status on root aerenchyma formation and radial oxygen loss from roots were also evaluated. Seven rice cultivars were grown in sand culture fertilized with nutrient solution under well drained and hypoxic conditions. Oxygen concentration was measured colorimetrically 6 h after placing plant roots in the Ti3+ ‐citrate solution. Plants were harvested for root porosity and radial oxygen loss estimates at 14 and 35 d after transplanting. Estimates of radial oxygen loss with the Ti3+‐citrate technique were comparable to those obtained with a polarographic oxygen electrode. Both radial oxygen loss and root porosity were enhanced by hypoxia. Rapid formation of aerenchyma at early growth stages coupled with correspondingly high O2 leakage from roots may explain why some rice cultivars cope with the adverse effects of anaerobiosis better than other cultivars.
Wind Erosion Losses as Related to Plant Silhouette and Soil Cover
Authors: Bilbro J. D. , Fryrear D. W. 
Published: July 2010

AbstractWind erosion adversely affects soils, plants, animals, equipment, the environment, and people. Wind erosion can be minimized or prevented by either standing residue or flat residue cover. Our objective was to develop mathematical relationships between these two crop residue properties and soil loss ratio (SLR: soil loss from protected soil/soil loss from flat, bare soil), for more accurate predictions of wind erosion soil losses. Therefore, from a previously reported wind tunnel study (wind tunnel 1.1 m high, 0.51 m wide, and 5 m long) we took data for velocities ranging from 9.4 to 16.1 m s−1 and silhouette areas (S) of upright wood dowels (simulating plant stems) ranging from 31 to 813 cm2 m−2 of soil surface (washed sand <0.42 mm) and developed the following equation for standing residue and SLRs: SLRs = exp(−28.49 × S0.6413/V2.423) (r2 = 0.95), where S = stalk height (cm) × stalk diameter (cm) × stalk density (no. m−2) and V = wind velocity in m s−1 at a height of 0.61 m. We combined data from a second previously reported wind tunnel (0.9 m high, 0.6 m wide, and 7 m long) study in which the soil had been covered from 0.0 to 80.0% with wood dowels, artificial clods, or cotton (Gossypium hirsutum L.) gin trash with data from field studies published by other researchers for various soil types and soil coverages ranging from 8 to 95% with wheat (Triticum aestivum L.) residue or gravel, and developed the following equation for soil cover and SLRc: SLRc = exp(‐0.04380 × psc) (r2 = 0.94), where psc is the percent of the soil that is covered by nonerodible material (e.g., soil aggregates, rocks, plant material). These equations should be useful to researchers developing and evaluating wind erosion models, prediction systems, and wind erosion control practices.
Root Hydraulic Conductivity and Its Components, with Emphasis on Desert Succulents
Authors: Huang Bingru , Nobel Park S. 
Published: July 2010

AbstractPlant growth and development are often limited by the ability of roots to extract water and nutrients from the soil and to transport them to the shoots. The water absorption and transport ability of roots can be quantified by the hydraulic conductivity, LP. This quantity can be considered in terms of two components, the radial conductivity (LR) for water movement into the root and the axial conductance per unit pressure gradient (Kh) for water movement along the root xylem. The pathways for water movement through roots are discussed, and the hydraulic conductivities are expressed mathematically. The techniques currently used for determining LP, LR, and Kh are presented and conductivities for various plant species are compared. Recent experimental results on structural factors controlling LP and Kh together with the influences of two major environmental factors, temperature and soil water availability, are analyzed for roots of desert succulents. Interpreting the anatomical and physiological controls for LP, LR, and Kh and the variations caused by environmental factors is essential to understand the functioning of root systems for water uptake.
Root‐to‐Shoot Communication in Flooded Plants: Involvement of Abscisic Acid, Ethylene, and 1‐Aminocyclopropane‐1‐carboxylic Acid
Authors: Jackson Michael B. 
Published: July 2010

AbstractNonhydraulic communication between roots and shoots of flooded plants is reviewed. Contrary to reports for roots of droughted plants, those of flooded tomato plants (Lycopersicon esculentum L.) did not export increased amounts of abscisic acid (ABA) to the shoots, even though stomata closed in association with increased foliar ABA, and in the absence of marked losses in leaf hydration. Flooded tomato root systems did export more of the ethylene precursor 1‐aminocyclopropane‐1‐carboxylic acid (ACC). Ethylene formed in the leaves by oxidation of the ACC to ethylene and the epinastic leaf curvatures the ethylene induced were found to be inhibited in tomato plants transformed with an antisense gene to the ethylene‐forming enzyme ACC oxidase. Our estimates of the concentration and delivery of ABA and ACC in the xylem sap as it passes into the shoot from the roots avoided artifacts associated with variable sap flow rates and temporary contamination from wounded tissue. Measurements of ethylene production by individual roots of intact seedlings of maize (Zea mays L.) by highly sensitive photoacoustic laser detection confirmed earlier work linking enhanced ethylene evolution with more extensive aerenchyma development in roots that are partially deficient in oxygen. The development of aerenchyma enhances oxygen movement from shoots to roots.
Soybean Pubescence Color Influences Seed Yield in Cool‐Season Climates
Authors: Morrison Malcolm J. , Voldeng Harvey D. , Guillemette Ron J. D. 
Published: July 2010

AbstractSoybean [Glycine max (L.) Merr.] pubescence color (gray or tawny) may influence the microclimate of the canopy and consequently the seed yield. The objectives of this research were to examine the influence of pubescence color on the seed yield of soybean. Yield data were collected from soybean with either gray or tawny pubescence grown in a regional adaptation trial for three years at three locations. Mean yield, yield stability, and general adaptability were examined to determine if pubescence color interacted with the climate to affect yield. In years or locations receiving >2600 corn heat units (CHU), soybean lines with gray pubescence had either significantly higher yield or the same yield as lines with tawny pubescence. In years or locations receiving <2600 CHU, however, tawny soybean had a significantly higher yield than gray soybean. In cool‐season climates, soybean lines with tawny pubescence had greater seed yield stability and higher general adaptability than those with gray pubescence.
Turgor Potential and Osmotic Constituents of Kentucky Bluegrass Leaves Supplied with Four Levels of Potassium
Authors: Carroll Mark J. , Slaughter Leon H. , Krouse John M. 
Published: July 2010

AbstractSolute accumulation is one mechanism by which plants are able to sustain positive leaf turgor potentials (ψt). Potassium, the cation most often found in greatest concentration in Kentucky bluegrass (Poa pratensis L.), can influence accumulation of solutes. A 2‐yr glasshouse study was conducted to determine the effect of K availability on accumulation of six osmotically active solutes and ψ1 within leaves of Kentucky bluegrass. Four nutrient solutions containing 0, 10, 100, or 124 mg K L−1 were applied three times weekly to plants grown in silica sand. Small increases in K (0 to 10, or 100 to 124 mg L−1) had no effect on ψt but increasing K from 0 or 10, to 100 or 124 mg L−1 increased leaf ψt 0.19 to 0.35 MPa. Increasing K from 10 to 100 mg L−1 caused leaf osmotic potential (ψЛ) to decline by 0.17 to 0.23 MPa. Potassium was the only measured osmotically active solute that could account for most of the decline in ψЛ. When the supply of K was increased from 10 to 100 mg L−1, the resulting increase in leaf K concentration caused the calculated contribution of K alone to depress leaf ψЛ by 0.29 to 0.31 MPa. Conversely, the combined calculated osmotic contribution of Ca, Mg, glucose, fructose, and sucrose increased leaf ψЛ by 0.12 to 0.13 MPa when K was increased from 10 to 100 mg L−1. The calculated osmotic contribution of all six osmolytes accounted for 46 to 60% of the measured ψЛ. Increasing Kentucky bluegrass K tissue concentration appears to have a small but positive influence in increasing leaf turgor.
Irrigation and Culm Contribution to Yield and Yield Components of Winter Wheat
Authors: McMaster Gregory S. , Wilhelm Wallace W. , Bartling Patricia N. S. 
Published: July 2010

AbstractWater is generally the limiting factor in U.S. Great Plains wheat (Triticum aestivum L.) production. With increasing demands for limited water, improving the efficacy of irrigation is critical. One technique is to irrigate during responsive stages of crop development, but few studies have examined this approach. This 2‐yr study on a Nunn clay loam soil (fine, montmorillonitic, mesic Aridic Argiustoll) was designed to examine the effects of irrigation, based on stage of crop development, on winter wheat yield, yield components (on a plant basis), and specific culm responses. In the first year, the treatments were control (dryland), and irrigation at late jointing. In the second year, the treatments were dryland, irrigation at late jointing, irrigation at anthesis, and irrigation at both late jointing and anthesis. Irrigation at late jointing or anthesis significantly increased grain yield and the most important yield component (spikes per plant), as well as spikelets per plant, number of kernels per plant, and kernel weight per plant. The increased spikes per plant in the irrigation treatments, particularly with late‐jointing irrigation, was due to reduced tiller abortion. Increased yield was primarily due to the contribution of more secondary tillers (T10, T11, T20, T21, T30, and T31) that produced spikes. The contribution of main stems to the total yield decreased from 92% to at most 86% with irrigation, although the dry weight of main‐stem spikes increased with irrigation. The contribution to total yield of the main yield‐producing tillers, Tl and T2, decreased from 20 to 15% and 19 to 15%, respectively, with irrigation. As with main‐stem spikes, irrigation also increased T1 and T2 spike dry weight. Therefore, the production of secondary spikes due to irrigation treatments was not at the expense of main stem or primary tiller spikes. If only one irrigation can be applied, irrigation at late jointing is recommended for central Great Plains conditions, due to its greater effect on tiller survival. This implies that developmental and physiological processes at late jointing are critical in determining final grain yield, and water stress should be avoided at this growth stage.
A Simple Conductimetric CO2 Analyzer with Automatic Recalibration: I. Design, Implementation, and Functionality
Authors: Acock Basil , Wall Gerard W. 
Published: July 2010

AbstractControlled‐environment plant growth cabinets may be used to investigate the long‐term effect of elevated carbon dioxide concentration ([CO2]) on plant growth. Infrared gas analyzers (IRGAs) are normally used to monitor and control [CO2] in plant cabinets. With many cabinets in use, however, it soon becomes impractical to purchase an individual IRGA for each cabinet. A more economical method of monitoring and controlling [CO2] relies on the change in electrical conductivity when CO2 is dissolved in demineralized water. This work describes the design, implementation, and functionality of an inexpensive conductimetric system for controlling [CO2] in plant growth cabinets. Regressing electrical conductivity against [CO2] over the range 0 to 1000 μL L −1 yields a quadratic response. Calibration drift inherent in the conductimetric CO2 analyzer requires that each analyzer be recalibrated periodically. Automatically recalibrating with an IRGA every 900 s gave control of the [CO2] within the plant enclosures to within 10 to 15 üL L−1 of the set point. The [CO2] control system is robust enough to maintain this accuracy regardless of the desired [CO2] set point or the mass of plant material within the plant growth cabinet. In this approach, only one IRGA is required to control [CO2] in many plant growth cabinets if each cabinet has a dedicated conductimetric CO2 analyzer.
Alfalfa Establishment with Barley and Oat Companion Crops Differing in Stature
Authors: Simmons Steve R. , Sheaffer Craig C. , Rasmusson Donald C. , Stuthman Deon D. , Nickel S. E. 
Published: July 2010

AbstractSmall‐grain companion crops are commonly used for establishing forage legumes in the north‐central USA. Semidwarf‐stature barley (Hordeum vulgare L.) and oat (Avena sativa L.) show promise as less competitive and more lodging‐resistant companion crops. This study compared forage production and agronomic characteristics of companion‐cropped semidwarf and conventional‐stature genotypes of barley and oat. Alfalfa (Medicago sativa L.) was seeded both with and without companion crops in experiments conducted at St. Paul, MN, from 1987 through 1989 on a Waukegan silt loam soil (fine‐silty over sandy or sandy‐skeletal, mixed, mesic Typic Hapludoll). Both semidwarf and conventional‐stature barley and oat genotypes were evaluated. Small‐grain and alfalfa forage harvests were made at the boot and soft dough stages of the small grain. Subsequent alfalfa harvests also were made later in the establishment season and at first flower in the following spring. Light penetration through the canopies of the various companion crops was monitored in all years. Weed biomass was measured in 1989, to estimate weed suppression by the companion crops. Light intensity at the level of the alfalfa within the semidwarf companion crop canopy was consistently higher than within the conventional‐stature companion crops. Averaged over all small‐grain genotypes, companion crop treatments produced from 202 to 2355 kg ha−1 more forage dry matter than direct‐seeded alfalfa (no companion crop). Alfalfa dry matter production during establishment was suppressed by all companion crops, especially those with conventional stature. Weeds were greatly suppressed by all companion crops. Companion crops increased mortality of alfalfa plants during establishment, but did not lower production of the alfalfa at subsequent harvests in the establishment season or in the following spring. Overall, semidwarf and conventional barley and oat were comparable in performance as companion crops in these studies, but semidwarf genotypes should prove particularly advantageous under conditions where lodging is likely to occur.
Hairy Vetch Kill Date Effects on Soil Water and Corn Production
Authors: Clark Andrew J. , Decker A. Morris , Meisinger John J. , Mulford F. Ronald , McIntosh Marla S. 
Published: July 2010

AbstractHairy vetch (Vicia villosa Roth) can fix N2 for subsequent release to a corn (Zea mays L.) crop, but kill date effects on vetch N accumulation, soil water, and subsequent corn production have not been studied. A hairy vetch cover crop can deplete soil water through transpiration, but cover crop mulches can conserve soil water for no‐till corn. In order to determine optimum spring kill date and corn fertilizer N (FN) rates, hairy vetch was killed early April, late April, or mid‐May, followed by three corn planting dates and four FN rates (0, 45, 135, and 202 kg N ha−1). From early April to mid‐May, hairy vetch aerial phytomass and N content increased significantly, from 2800 to 4630 and 96 to 149 kg ha−1, respectively. Corn grain yields ranged from 5.2 to 10.1 Mg ha−1 and were significantly greater following mid or late kill, compared with early kill of vetch, regardless of corn planting date or FN rate. Gravimetric soil water under mid‐ or late‐kill vetch was often significantly greater than after early‐kill vetch. We conclude that soil water conservation by late‐killed vetch mulches had a greater influence on corn production than vetch spring water use. Optimum N production and water conservation occurred when vetch was killed the last week of April. Earlykill vetch sacrificed N production and minimized soil water conservation, resulting in reduced corn grain yield. Late kill did not add significant N benefits, but could deplete soil water or interfere with timely corn planting.
A mobile, Self‐contained, Simulated Rainfall Infilrometer
Authors: Radke Jerry K. 
Published: July 2010

AbstractWater infiltration rates into soils can provide important insights into the physical properties of the soil and its potential for crop production. Rainfall infiltrometers can make measurements under conditions closer to natural rainfall than ponded or tension infiltrometers. In the past, field measurements of infiltration with rainfall simulators have required the transport and assembly of bulky equipment. A self‐contained rainfall infiltrometer was designed and constructed on a high‐clearance tricycle tractor that can be easily transported over roads on a trailer and then driven in cropped or uncropped field plots. Performance of the unit is the same as the trailer‐based infiltrometer that it replaced.
Wind and Windblown Sand Damage to Pearl Millet
Authors: Michels Karlheinz , Armbrust Dean V. , Allison Bruce E. , Sivakumar Mannava V. K. 
Published: July 2010

AbstractPearl millet [Pennisetum glaucum (L.) R. Br.] is grown worldwide in areas affected by wind erosion, but no data on associated damage to millet are available. Laboratory wind tunnel experiments were conducted to determine the kind and extent of damage to millet caused by wind, sandblasting, and burial. In Exp. 1, millet was exposed for 15 min to wind (8, 11, or 14 m s−1) or wind + sand (8.3, 25.0, or 41.7 g m−1 s−1 sand abrader flux) at 8 and/or 16 d after emergence (DAE). Viable leaf area, leaf net photosynthesis, and NO3 content were measured through 21 DAE and dry matter production through 57 DAE. In Exp. 2, millet was seeded as three single seeds or in tufts, exposed to 25 g m−1 s−1 sand flux for 15 min at the 1‐, 2‐, or 3‐leaf stage, and then manually covered by 15 mm sand. Survival was monitored weekly; dry matter was determined 70 DAE. In Exp. 1, survival was uniformly 100%. Wind alone or low sand flux had no effect on viable leaf area. High sand flux decreased viable leaf area by 74% at 2 d after the 8‐DAE exposure and 42% at 5 d after the 16‐DAE exposure. Photosynthesis of the remaining leaf area was reduced up to 88% immediately after exposure compared with the control, and NO3 content of sandblasted millet was increased up to six times. Dry weight was reduced 40% at 21 DAE by the highest sand flux, but 9.7% at 57 DAE. In Exp. 2, burial decreased millet survival and dry weight. Buried tufts had a higher survival rate and 35% more dry weight than buried single plants. Millet buried at the 1‐leaf stage had 28% higher survival than plants treated later. Sandblasting reduced dry matter of buried millet only. Regression analyses between calculated total kinetic effects and growth parameters showed low r2 values. Millet can survive short‐term sandblasting at any growth stage, but growth is reduced by strong sand flux, a sequence of wind erosion events during early growth, or by combinations of abrasion with burial by blown sand.
Evaluation of Excess Soil Phosphorus Supply for Corn by the Ear‐Leaf Test
Authors: Mallarino Antonio P. 
Published: July 2010

AbstractThe P concentrations of ear leaves at silking are often used to assess P status of corn (Zea mays L.). The ear‐leaf test has been evaluated for its ability to detect P deficiencies, but little attention has been given to its ability to quantify excess P supplies. The quantification of high P supplies is important for both economic and environmental reasons and because fertilization has increased P supplies of many soils to levels where additional yield responses are not likely. Grain yields and tissue samples were collected from 41 site‐years corresponding to 2 long‐term and 24 short‐term P‐response trials from 1980 to 1990. The sites included a wide variety of soil types, soil‐test P values, and management practices. Phosphorus fertilization increased corn yields at 13 site‐years and leaf P concentrations at 24 site‐years. Fertilization increased leaf P concentrations at 85% of the soils where fertilization increased yields but at only 46% of the soils where fertilization did not increase yields. The determined critical concentration range for the leaf test, based on various models fit to relationships between yields and leaf P concentrations, was 2.3 to 2.5 g kg−1. This range is below or within the lower range of previously published critical concentrations for this test. Leaf P concentrations increased curvilinearly with increasing soil‐test values, and there were small or no increases at high soil‐test values. This trend, together with the failure of fertilization treatments to increase leaf P concentrations at many high‐testing soils, indicates limited luxury uptake of P in the leaves. The results of this study show that the ear‐leaf test does not evaluate excess soil P supplies appropriately and is not a reliable diagnostic tool for regions having abundant high‐testing soils. The inappropriate evaluation of excess P and the high variability in leaf P concentrations due to growth factors other than P availability limit the value of this test to the diagnosis of severe P deficiency.