bluuebunny/crossref_metadata_2025 huggingface dataset:
Management of Land Diverted from Crop Production. II. Annual Cover Crops and Fallow1
Authors: Robinson R. G.
Published: July 2010

Cover crops belonging to the Cruciferae, Gramineae, and Leguminoseae families, summer fallow, and annual weed cover were compared in weed control and effect on the next year's corn (Zea mays L.) and sunflower (Helianthus annuus L.) crops.

Corn yields were increased if legumes were present in the cover crop. Some grass‐legume mixtures gave more weed control at lower seed costs than pure legumes, and corn following some mixtures yielded as much as corn following pure legumes. Annual Cruciferae gave satisfactory performance at very low seed costs. Corn following most cover crops yielded considerably more than corn following annual weed cover. Sunflower yields following the cover crops did not differ significantly.

Corn but not sunflower following summer fallow showed retarded growth and lighter green foliage than after cover crops. The symptoms disappeared in mid‐summer, but corn ear moisture was high at harvest. Concentrations of 14 chemical elements in corn and sunflower indicated that, except in P, composition of both crops responded similarly to cover crops and summer fallow. P concentration in corn plants after summer fallow was lower than after cover crops.
Chemical Composition and Yield of Corn as Affected by Deep Placement of Dolomitic Limestone1
Authors: Lutz J. A. , Jones G. D.
Published: July 2010

An experiment was conducted on Tatum silt loam to measure the effects of placement of 0, 22.4, and 44.8 mt/ha of dolomitic limestone on the plow sole (30.5 cm) in the spring of 1968 on the yield and chemical composition of corn (Zea mays L.). Treatments consisted of 0, 12.2, 24.4, and 48.8 kg P/ha without K; 24.4 and 48.8 kg P/ha with 23 kg K/ha; and 48.8 and 97.6 kg P/ha with 46 kg K/ha with each rate of lime. The P and K treatments were surface applied and disced in.

Placement of lime on the plow sole increased the yield of corn. The P, K, and Ca contents of corn leaves were increased, the Mg content decreased, and the N content was unaffected by deep lime placement. Corn yields were affected by P and K treatments.
Effects of Irrigation Water Temperature on Soil Temperature1
Authors: Wierenga P. J. , Hagan Robert M. , Greogory E. J.
Published: July 2010

Soil temperatures were measured in fields irrigated with normal and cold water and in unirrigated soil, to study the effects of irrigation water temperature on soil temperature. Temperatures were measured with probes made of thermocouple wire enclosed in 3 mm O.D. stainlesssteel tubing. The probes were inserted vertically into the soil. Errors in temperature measurement resulting from heat conduction along the probes were on the order of 0.1 C or less. The effects of irrigation water temperature on soil temperature were small and of short duration. Differences in soil temperature resulting from irrigation with water of 27 and 14 C lasted for less than 24 hours at 5 and 10 cm, and for 60 hours at 30 cm. Irrigated soil temperatures were significantly reduced by evaporative cooling from the soil surface after irrigation in mid‐April, though not in mid‐February.
Method for Precision Planting Small Plots of Soybeans1
Authors: Arthur R. E. , Davis W. H. , Shepherd E. L.
Published: July 2010

abstract

A punched belt, precision seed placement vegetable planter was combined with a vacuum seed extraction method in order to allow precision planting of uncounted seeds into a uniform population plot regime.
Split Appointments in Agronomy1
Authors: Robison L. R. , Fenster C. R. , Flowerday A. D.
Published: July 2010

A questionnaire on attitude toward split appointments was sent to 350 extension agronomists in the United States, Of those responding, 38.5% were on split appointments and 64.7% were in favor of them. Those respondents with a research division or who desired a research division indicated the necessity of technician and budget support for such an appointment to be successful.
Multidimensional Approaches in Autotutorial Teaching of the Crop Science Laboratory1
Authors: Burger A. W. , Everly J. C. , Steele J. C.
Published: July 2010

In the summer of 1968, an undergraduate instructional award was granted for two courses in the Department of Agronomy at the University of Illinois (Urbana‐Champaign campus). Introductory Crop Science, a 4‐semester hour credit course was converted from 3 hours of lecture and 2 hours of laboratory to 2 hours of lecture and up to 2 hours of scheduled, programmed independent study per week in a constantly supervised carrel‐science laboratory environment. The crop science laboratory procedure incorporates bi‐weekly, 1‐hr discussions, completion of each student's assigned experiment reported in publishable form, and opportunity for bonus credit by completion of an open‐end experiment. Favorable student reaction to autotutorial instruction, the use of taped comments by a writing consultant to give the student sugestions on improving writing skills before submitting final report, and publication of every student's research report during three semesters involving 269 students were recorded.

Freshmen, majors in agricultural communications, agricultural science (graduate training), and agronomy, and students earning grades of A and B, respectively, devoted more time to independent study than upperclassmen, students in other curricula, and students earning grades below B.
Incorporation of EPTC and Trifluralin for Weed Control in Field Beans1
Authors: Fenster C. R. , Flowerday A. D. , Robison L. R.
Published: July 2010

Applications of a,a,a‐trifluoro‐2,6‐dinitro‐N,N‐dipropylp‐toluidine (trifluralin) at .56 and 1.12 kg/ha and S‐ethyl dipropylthiocarbamate (EPTC) at 1.68 and 3.36 kg/ha were incorporated before planting. Five different tillage implements were used to determine the influenc of incorporation on weed control effectiveness in field beans (Phaseolus vulgaris L.) cultivar ‘Great Northern UI 1140.’ Weed yields were lowest where .56 and 1.12 kg/ha of trifluralin and 3.36 kg/ha EPTC were used and incorporated 5.08 to 10.16 cm in the soil using the tandem disk. Bean seed and plant yields were significantly higher when herbicides were used.
Nitrogen Utilization in Blue Panicgrass1
Authors: Spiers J. M. , Holt E. C.
Published: July 2010

Blue panicgrass (Panicum antidotale Retz) plants were grown in a sand culture, subjected to contrasting forms of nitrogen fertilization applied at differing rates, and harvested at varying intervals following fertilization. A determination of total nitrogen in plant material was used to evaluate uptake efficiency. Fractionations of the total nitrogen portion into insoluble, soluble, nitrate, and soluble reduced N forms were used to evaluate the metabolic effectiveness of this grass.

Data indicate a ceiling rate of nitrogen uptake in blue panicgrass, but a high level of available nitrogen must be present in a growing medium to maintain a high level of uptake. Leaf samples contained a greater percentage of insoluble than soluble nitrogen with almost all of the soluble fraction made up of soluble reduced N compounds. Stem and root samples had less insoluble nitrogen than soluble. The ratio of nitrogen reaching the leaves to protein metabolism in the leaves remained relatively constant with no accumulation of nitrate in the leaves. In leaves, stems, and roots, there was a decline in protein N with time and a corresponding increase in the soluble N fraction. Nitrate‐N in stem and root samples decreased with time, with a corresponding increase in the soluble reduced fractions of these samples.
Modified Tube Solarimeters for Additive and Net Measurements of Visible, Infrared and Solar Radiation1
Authors: Luxmoore R. J. , Millington R. J. , Aston A. R.
Published: July 2010

A tube solarimeter was modified to measure energy (310‐ to 2,700‐nm waveband) received on upper and lower surfaces to give either an additive or a net measurement. A glass filter fitted to a solarimeter provided an instrument sensitive to energy in the 700‐ to 2,750‐nm waveband. Visible energy (310‐ to 700‐nm waveband) may be measured by difference in readings of instruments without and with the filter. A solarimeter that directly measures energy in the 310‐ to 700‐nm waveband is described.
Vernonia anthelmintica: A Potential Seed Oil Source of Epoxy Acid. III. Effects of Line, Harvest Date, and Seed Storage on Germination1
Authors: White G. A. , Bass L. N.
Published: July 2010

Pre‐ and post‐frost harvested seeds of three lines of Vernonia anthelmintica (L.) Willd. were stored for 96 weeks under combinations of cold (0.6 C with 30 to 35% R.H.), room (25 to 30 C with uncontrolled R.H.) and barn (ambient temperature and R.H.) conditions to determine the effects of storage conditions on germination. The seed yield from the pre‐frost harvest of VS63‐40 significantly exceeded that of PI 283729. Seed yields of both lines from the post‐frost harvest were very low because of shattering. Pre‐frost harvested seeds were very dormant with an initial germination of 8 to 12%. Tetrazolium tests indicated viabilities of 86 to 89% for the three lines. The average initial germination of post‐frost harvested seeds was 12% and the viability was less than 50%.

Seeds in cold storage lost dormancy slowly, while seeds in room and barn storage reached maximum germination by 24 or 48 weeks. After this period, a gradual decline in germinability occurred. The best storage treatment used was 24 weeks at room conditions followed by cold storage. Seeds of VS63‐40 germinated higher than those of PI 283729 and VS65‐224. Seeds of VS65‐224 were the most dormant and were not suitable for planting without 48 weeks or more of room or barn storage. Seeds from frostkilled plants should not be used for planting purposes.
Effects of Seasonal Timing of Competition on Grain Yield Components of Winter Barley1
Authors: Green J. T. , Finkner V. C. , Duncan W. G.
Published: July 2010

Grain yield components in a bordered row of winter barley (Hordeum vulgare, L. emend. Lam.), and rows from which the borders were removed (by hoeing) at various times in the growing season, were compared for two cultivars. The yield component, number of spikelets per‐row‐length, was responsive to the more favorable environment, resulting from removed borders, until two or three weeks before head emergence. After that, stage removal of bordering rows produced no response. Weekly border‐row clipping, (removal of top growth and subsequent regrowth at weekly intervals), during the spring growing season did not increase this component. Only slight differences in average kernel weight resulted from different duration of border competition. Primary yield differences among treatments for both cultivars were due to number of heads per‐unit‐row‐length and this was related to tiller mortality rather than the total number of tillers.
Effect of Two Growth‐Regulating Chemicals on Yield and Water Use of Three Perennial Grasses1
Authors: Mathias E. L. , Bennett O. L. , Jung G. A. , Lundberg P. E.
Published: July 2010

Growth responses of smooth bromegrass (Bromus inermis Leyss), Kentucky‐31 tall fescue (Festuca elatior L.), and common Kentucky bluegrass (Poa pratensis L.) to the growth‐regulating chemicals F‐529 (N‐pyrrolidinosuccinamic acid) and Cycocel (2‐chloroethyltrimethylammonium chloride) were studied. Growth of grasses was reduced to near zero when Cycocel was applied at a concentration of 0.584M, with at least some retardation occurring up to 100 days after application.

F‐529 was less effective than Cycocel in retarding grass growth. Maximum reduction occurred at the 0.45M concentration where growth was reduced to 35% of the control, and at 70 days following application there was no reduction. Recovery from both chemicals was generally followed by a period of stimulated growth.

Water use, in general, was highly correlated with amount of top growth.

Food reserves of plants as determined by eiolated growth were significantly reduced only at the 0.292M and 0.584M concentrations of Cycocel, where severe foliar damage had occurred.
Rt esponse of Cotton to Boron1
Authors: Murphy B. C. , Lancaster J. D.
Published: July 2010

Field experiments were conducted with rates and methods of application of B to cotton. Broadcast was as effective as drilled, foliar application was as good as soil application, and there was no advantage to a combination of soil and foliar application. A highly soluble source of B was superior to a more slowly soluble one.

Young leaves, the third or fourth node from the growing point, were found to have a critical level of about 15 ppm B. Mature leaves occurring at the fifth and sixth nodes from the growing point had a B content of 5 to 10 ppm higher. The critical level of hot‐water soluble B in the top 15 cm of soil was in the range of 0.10 to 0.16 ppm.
Rates of Net Carbon Dioxide Assimilation in Rice as Influenced by Growth Temperature and Photoperiod1
Authors: Azmi A. R. , Ormrod D. P.
Published: July 2010

Plants of ‘Bluebonnet,’ ‘Caloro,’ ‘Dokri,’ and ‘Kangni’ cultivars were grown for 2, 4, 6 and 8 weeks in growth cabinets using temperatures of 35/18, 35/26.5, 35/35 and 40.5/18 C day/night and photoperiods of 8, 10, 12 and 14 hours.

The rate of net CO2 assimilation on a leaf blade weight basis was highest at 2 weeks in all varieties at all temperatures and photoperiods and declined with age. The greatest decline at 8 weeks compared to 2 weeks was 71% in Dokri and least was 65% in Bluebonnet. The assimilation rate was consistently higher in plants grown in 8‐hour photoperiod. Compared to 14‐hour, the rate at 8‐hour was higher by 28 and 25% at 6 and 8 weeks, respectively. In most cases, the highest assimilation rates were recorded at 40.5/18 and 35/35 C. Both Bluebonnet and Caloro had higher assimilation rates than Dokri and Kangni.
Boron and Manganese Effects on Protein, Oil Content, and Fatty Acid Composition of Cottonseed1
Authors: Anderson O. E. , Worthington R. E.
Published: July 2010

Field experiments were conducted to study the effect of Mn and B on the oil and protein content and the fatty acid composition of cotton‐seed produced on soils where supplements of these elements have increased yields of lint cotton. Manganese and B, in separate experiments, were applied to the foliage or to the soil at three growth stages. With only one exception, neither time nor method of applying B or Mn to cotton influenced the oil or protein content, or the distribution of fatty acids within the seed oil. In the single exception, a small but significant increase in oil content occurred when B was applied to the foliage at the 5‐ to 10‐leaf stage. There were negative correlations (P = .01) between seed protein and oil for both Mn and B. Seed oil and protein content varied among locations due to factors other than available soil Mn or B.
Water Stress and Stem Radial Contraction of Cotton Plants (Gossypium hirsutum L.) under Field Conditions1
Authors: Namken L. N. , Bartholic J. F. , Runkles J. R.
Published: July 2010

Radial contraction and expansion of cotton plant stems (Gossypium hirsutum L.) were monitored with linear variable displacement transducers throughout the 1969 and 1970 growing seasons under field conditions. Relative water content and water potential measurements of the leaves were routinely made as indices of water stress of the cotton plant for comparison with stem contraction measurements. The amount of stem radial contraction was directly related to the water‐stress indices of the cotton plant. Stem contraction was more sensitive to plant water stress as stress increased. No contraction occurred until relative water contents were below 79 or 83%, depending on stage of plant growth, or until leaf water potentials were lower than −8.0 bars.

The relation between relative water content and stem contraction was influenced by stage of plant growth. A higher degree of plant water stress was required to provide an equivalent radial change during the square and early bloom period when vegetative growth rates were high than during the late bloom and boll development period when vegetative growth rates were low. Stage of plant growth did not affect the relation between leaf water potential and radial stem contraction.

Leaf water potential recovered more rapidly than cotton stem contraction. However, the relation was well defined for the desorption phase of the stress cycle from minimum stress in early morning (0600 hr) to maximum stress at about 1400 hr.
Effect of Race T of Helminthosporium maydis on Corn Grain Yield1
Authors: Jellum M. D. , Ethredge W. J.
Published: July 2010

The effect of southern corn leaf blight (Helminthosporium maydis) on corn (Zea mays L.) yield as related to dates of planting was determined in 1970 at two locations in Georgia. Estimates of yield loss were based on the relative yields of six susceptible hybrids and one resistant hybrid grown under disease‐free conditions in 1969 and under a severe epiphytotic of southern corn leaf blight in 1970. Yield of susceptible hybrids from the earliest planting date (April 8 and 9) was not reduced by leaf blight in 1970. Yield was reduced by 23% when hybrids were planted on May 8 in the Piedmont region, compared with 46% when planted on May 1 in the Upper Coastal Plain region. A late planting date at each location resulted in an estimated yield loss of 71%.
Growth Patterns of Irrigated Sugarbeet Roots and Tops1
Authors: Johnson Wendell C. , Davis Ronald G.
Published: July 2010

Electronic growth sensors were used in the field near Amarillo, Texas, to obtain continuous records on strip chart recorders of the root and top growth of irrigated sugarbeets (Beta vulgaris). The purpose of the study was to characterize the typical diurnal variation in growth rate of the crop and to determine its growth response to variations in ambient atmospheric and soil conditions. The growth sensors were potentiometers, either constructed in the form of slidewire discs or adapted from commercial linear transducers. The root sensors were operated by a pulling action of a noose surrounding the root. The height sensors were rotating slidewire discs attached with fine wires to leaf tips.

The growth patterns of sugarbeet roots and tops were very similar with most of the growth occurring at night. The main difference was a decrease in size of roots during the daytime that did not occur with leaves.

On a typical day with few clouds in July or August and with the plants under a moderate moisture stress, the growth rate of roots and tops accelerated suddenly about an hour before sunset and reached a peak or maximum point around sunset. Growth continued at a high rate during the night. The growth rate of roots usually reached a secondary peak between midnight and sunrise. The growth rate of roots and tops decreased rapidly after 7 to 8 A.M. and little or no growth took place during the middle of the day. The normal dear−day growth pattern was altered by high moisture stress as well as by cloudiness and rain showers.
Soil Heating Studies with Cool Season Turfgrasses. IV. Energy Requirements for Electric Soil Heating1
Authors: McKiel C. G. , Ledeboer F. B. , Skogley C. R.
Published: July 2010

Electrical energy use was recorded for soil heating studies conducted in turf from 1967 to 1969. Heating densities of 54 W/m2 (5W/ft2), 108 W/m2 (10 W/ft2), and 162 W/m2 (15 W/ft2) were employed. Energy consumption was a function of environmental conditions. Regression lines were constructed from kilowatt‐hour and degree‐day data. These data should be useful for estimating energy requirements of similar soil heating installations in turf.
Comparison of Partially Acidulated Rock Phosphate and Concentrated Superphosphate as Sources of Phosphorus for Corn1
Authors: Lutz J. A.
Published: July 2010

The data available measuring the relative efficiencies of acidulated rock phosphate at various levels of applied P are limited, and further investigation of this subject is warranted. Florida rock phosphate was acidulated with H3PO4 at 20 and 100% of that required to convert rock phosphate to concentrated superphosphate. These two materials plus a check (0 P) were applied as treatments for corn (Zea mays L.) during three consecutive years on an acid soil in field experiments. Rates of total P from each source were 0, 10, 20, 30, and 100 kg/ha, which was broadcast and disked in each year just prior to planting.

There was an excellent response to P fertilization. Corn yields were similar from both sources of P at some rates of applied P, while at other rates, P from concentrated superphosphate appeared to be the superior source. Phosphorus content of the ear leaves was not affected by P source in 1968, but differences were evident in 1969 and 1970. Leaf K content in 1970 was significantly increased by the highest rate of applied P from both P sources. There was an increase in available soil P only at the highest rates of applied P.

At low rates of applied P, CSP was the most economical source of P. At the highest rate of P application, the 20% acidulated rock phosphate appeared to be more economical
Factors Affecting Zinc Absorption by Corn from Volcanic Ash Soils1
Authors: Marinho M. L. , Igue K.
Published: July 2010

In high P‐fixing soils, such as volcanic ash soils and tropical oxisols, the need for heavy P application may be of consequence in the absorption of Zn. The objectives of this study were to determine the availability of native and applied Zn in three soils considered deficient, to determine the effect of P application and the level of free R2O3 in the soil on Zn absorption, and to correlate Zn absorption with soil tests.

The amount of Zn extracted with 0.01 M Na2‐EDTA and 0.1 N HC1 increased with Zn applications and decreased as the free R2O3 content increased. P applications increased the amount of Zn extracted by the EDTA method, but did not show any definite trend in the case of the HC1 method, although higher amounts of Zn are extracted by the latter.

The total amount of Zn absorbed by the corn (Zea mays L.) plant increased with Zn application and decreased as the free R2O3 present in the soil increased. The effect of P was not statistically significant. However, Zn concentration in the tissue decreased as the free R2O3 content and applied P increased. The L value also increased with Zn application, but P application had no definite effect on it. Higher correlation coefficients between Zn absorption and soil‐extracted Zn were obtained from the EDTA method as compared to the HC1 method. The EDTA method also correlated better with the L value than with the HC1 method.
Environmental Factors Affecting Root Development and Reserve Carbohydrates of Bermudagrass Cuttings1
Authors: Burns Robert E.
Published: July 2010

Bermudagrass (Cynodon sp.) cuttings were grown in growth chambers to determine the effect of temperature, light intensity, and daylength on root development. Total root length, average length of root, number of roots, and roots per node were less when grown under lower temperature, (27/15 C vs. 32/24 C), light intensity (800fc vs. l,500fc), or daylength (10 hr vs. 16 hr). Root branching was 67% less at the low temperature, 42% less in low light intensity, but was not affected by daylength. Reserve carbohydrates were less with short daylength or low light intensity, but were higher under low temperature. The number of cuttings that produced no roots, those on which new shoots developed, and the number of nodes producing roots varied independently of temperature, daylength, or light intensity. Light intensity and temperature appear to be as important as daylength in the performance of late‐sprigged bermudagrass.
Sensitivity of Southern Peas to Plant Water Deficit at Three Growth Stages1
Authors: Hiler E. A. , van Babel C. H. M. , Hossain, M. M. , Jordan W. R.
Published: July 2010

Response of southern peas (Vigna sinensis L. Endl. var. Burgundy) to different levels of water deficit at three different stages of growth was measured in a greenhouse. In each stage, plants were stressed to three levels of leaf water potential: — 14 bars, — 21 bars, and —28 bars. Crop susceptibility factors (fractional reductions in yield compared to a nonstressed treatment) were determined for each stage of growth and level of plant water deficit. The flowering period was found to be the most sensitive stage, regardless of deficit level. The pod development stage was found to be least sensitive to level of deficit. A water deficit of — 28 bars, however, caused a yield reduction of greater than 50% for all growth stages. Stress‐day index values were calculated and related to crop yield. The use of the stress‐day index concept in irrigation scheduling is discussed. Leaf water potential varied linearly with soil water potential between 0 and — 15 bars. Leaf diffusion resistance became high and transpiration was negligible after the leaf water potential reached — 10 to — 12 bars; the corresponding soil water potential was — 5 bars. Water‐use efficiencies were highest for the nonstressed treatment and the treatment with the low deficit level during the first stage.
Effects of Increasing Amounts of Organic Residues on Continuous Corn: II. Organic Carbon, Nitrogen, Phosphorus, and Sulfur1
Authors: Larson W. E. , Clapp C. E. , Pierre W. H. , Morachan Y. B.
Published: July 2010

With the advent of well‐fertilized corn (Zea mays L.) raonocultures with large amounts of residues returned to the soil, the question arose as to whether organic matter could be maintained at satisfactory levels in Corn Belt soils. To answer this question changes in the amounts and composition of the soil organic matter were determined in a field experiment where different types [alfalfa (Medicago sativa L.), cornstalks, sawdust, oat straw (Avena sativa L.), and bromegras(Bromus inermis Leyss)] and amounts (from 0 to 16 tons/ha/yr) plant residues were added to Marshall silty clay loam (Typic Hapludoll) for 11 consecutive years. The soil was cropped to corn and large amounts of N fertilizer were added. Organic C, N, S, and P contents of the soils increased in proportion to the amount of plant residues added. After 11 years contents of the 0‐ to 15‐cm depth of the check plots were 1.6% C, 0.15% N, 0.023% S, and 0.018% P. Average increases over the check for C, N, S, and P were 47, 37, 45, and 14%, respectively, for the 16‐ tons/ha/yr treatment. Type of plant residue when added at 8 tons/ha/yr did not influence the C or P contents of the soils differently. The organic N and S contents, however, were lower with sawdust than with the other residues. Cumulative effects of increasing quantities of organic residues on available nutrients in the soils showed that NH4‐N production, weak‐acid‐soluble P, and exchangeable K increased significantly. The amount of cornstalk residue needed to prevent loss of organic C was estimated to be 6 t/ha/yr.
Digestion of Fresh Forage in Rumen Fluid1
Authors: Monson Warren G. , Powell Jerrel B. , Burton Glenn W.
Published: July 2010

This technique to evaluate digestion of fresh forage was developed as an additional tool for our forage breeding and evaluation programs. Leaf discs or segments were incubated in rumen fluid to assess the rate and progression of digestion of fresh forage samples. Digestion occurred at cut or broken surfaces as the cuticle formed a barrier to entry of rumen microflora. Differences in rate of digestion between species and between lines within a species were clearly apparent.
Effects of Variety, Seeding Rate, Companion Species, and Cutting Schedule on Crownvetch Yield1
Authors: Mays D. A. , Evans E. M.
Published: July 2010

Crownvetch (Coronilla varia L.) has previously been used for erosion control at several southern locations, but little or nothing was known of its productivity under intensive management or its competitive ability in mixtures with grasses of the region. At present seed prices the recommended seeding rate of 20 kg/ha or more would make establishment costs prohibitive.

With the increasing interest in crownvetch as a forage, it was necessary to learn whether it is adapted for intensive management in the South either alone or in mixtures and to show that establishment costs could be reduced by use of lower seeding rates.

‘Penngift,’ ‘Chemung,’ and ‘Emerald’ varieties of crownvetch were seeded at Muscle Shoals, Ala., at rates of 5.6, 11.2, and 22.4 kg/ha in pure stands. At the same time, Penngift was seeded at 2.8, 5.6, and 11.2 kg/ha with orchardgrass (Dactylis glomerata L.), tall fescue (Festuca elatior), and alfalfa (Medicago sativa L.)

Data from the pure stands indicated that there were no significant yield differences attributable to variety or seeding rate over a 2‐year period. New treatments were then assigned and the three varieties were subjected to two, three, or four cuttings annually. Four cuttings resulted in significantly less forage yield than two or three cuttings and caused severe stand loss after 2 years.

The presence of alfalfa in the seeding mixture depressed crownvetch establishment and long‐term yields. Mixtures with fescue or orchardgrass produced more total forage than crownvetch alone in 2 out of 4 years. A good legume‐grass mixture was maintained for 3 years, but there were severe crownvetch stand losses by the 4th year.

It was concluded that crownvetch is not adapted for intensive use as a forage plant in the South, although it seems well adapted for use as an infrequently cut ground cover.
Effect of Nitrogen Source on Corn and Bromegrass Production, Soil pH, and Inorganic Soil Nitrogen1
Authors: Power J. F. , Alessi J. , Reichman G. A. , Grunes D. L.
Published: July 2010

Little information is presently available on the effects of N source on dryland crop production in the Northern Plains. Therefore a field experiment was conducted for 4 years to assess the relative merits of ammonium sulfate, ammonium nitrate, calcium nitrate, and urea applied annually at 55 and 110 kg N/ha to both corn (Zea mays, L.) and bromegrass (Bromus inermis, L.) grown on a fine sandy loam (pachic haploboroll) with surface pH of 6.5 and no free carbonates. Plants were harvested at maturity and soils were periodically sampled for water content, inorganic N content, and pH. Corn production was highest for ammonium sulfate and ammonium nitrate at 110 kg N/ha. Leaf tissue at silking from all fertilized corn contained over 2.8% total N. Soil inorganic N accumulating during the first 3 years under corn was leached below the root zone by 514 mm of precipitation during the fourth growing season. At the 110‐kg N rate, bromegrass production was lowest with urea, possibly because of ammonia volatilization. Nitrate sources of N greatly enhanced early season growth of bromegrass. All fertilizer N applied was immobilized in the bromegrass ecosystem, prohibiting any carryover or leaching of soil nitrate. Soil pH changes due to fertilization were not reflected in plant growth.
Response of Tifway Bermudagrass to Sulfur on Sandy Soils1
Authors: Volk G. M. , Horn G. C.
Published: July 2010

It was the purpose of this investigation to determine if previously reported differential growth and color response of Tifway bermudagrass (Cynodon dactylon L. Pers.) on a loamy fine sand to various N and K sources in field plot tests correlated with S applied in these materials and S percentages in the grass. The growth response to (NH4)2SO4 over NH4NO3 correlated positively with S percentage increase in the grass. Subblock treatments of K sources within the 2 N sources showed a growth response and S percentage increase in the grass in increasing order for K2SO4, KCl, SuL‐po‐mag, and K2CO3, which did not follow the S applied as a component of the K source. Retention of applied SO4‐‐ by the mineral subsoil was negligible, but increase in total S in the surface soil probably was the result of build‐up of organic S during a 4‐ year period. There was no differential effect of NH4 + vs. NO3 on the uptake of S at the average N/S ratio of 12.5 and average S percentage of 0.35 in the grass. It is suggested that sulfate‐S application be coordinated with N application frequency on sandy soils.
Water Potentials in Nonwilted Dianthus Grown in Different Nutrient Solution Concentrations1
Authors: Schekel Kurt A. , Hanan Joe J.
Published: July 2010

Experiments were undertaken to determine if Dianthus caryophyllus L. adjusted its internal osmotic potential downward with decreasing solution potential and the concomitant effects on water and turgor potentials. Plants were grown in a gravel substrate, irrigated two to four times daily with solutions of varying potentials, and measurements were made from before sunrise to noon or shortly thereafter on clear days. Plant osmotic potentials adjusted to increase the potential gradient between solution and plant with decreasing solution potential. There were no observable differences between treatments with respect to stomatal aperture or leaf diffusion resistance. The xylem hydrostatic pressure decreased to a greater extent in plants grown in —1.0 bar solutions than in those grow in −0.3 bar solutions as atmospheric evaporative demand increased. Polynomial regressions of potential on evaporative demand had calculated correlations exceeding 0.90. Differentiation to determine the rate of hydrostatic potential change with change in evaporative demand showed the rate to be highest at low evaporative demands in plants grown in −1.0 bar solutions, gradually decreasing to 0 at high vapor pressure differences near 16 mm Hg. Carnations in −0.3 bar solutions had rates approaching O at low and high atmospheric demands, with a definite maximum near 9 to 10 mm Hg. The differences between hydrostatic potential and plant osmotic potential, ignoring matric and xylem potentials, showed carnations in −1.0 bar solutions to have consistently lower turgor potentials than plants grown in less concentrated solutions.
Response of Rice Plants Grown in Three Potted Luzon Soils to Additions of Boron, Sulfur, and Zinc1
Authors: Lockard R. G. , Ballaux J. C. , Liongson Emma A.
Published: July 2010

Three low‐yielding Luzon soils, Quingua clay loam, Bantog loam, and Umingan loam, on which plants did not respond sufficiently to N, P, or K, were tested in pot studies with three levels of B, S, and Zn in a 34 factorial design to show the response on the yield and nutrient content of rice (Oryza sativa L.).

None of the soils was deficient in B, as additions of B resulted in decreased yield and the development of foliar symptoms resembling those of B toxicity. Plants in two soils responded to the addition of S; those in Quingua clay loam gave a greater response than those in Bantog loam. Addition of Zn did not increase the yield of plants in any of the three soils. However, young plants growing in Umingan loam exhibited symptoms resembling those of Zn deficiency in treatment Zn0.

The level of each nutrient in the straw was increased by the addition of that nutrient to the soil. The most pronounced effect was on the S level in the plant when S was applied to the soil. The linear or quadratic equation to calculate this relationship is presented for each nutrient.

The highest level of B applied to the soil, treatment B2, significantly increased the level of S in the straw compared to treatment B0 but it did not increase yield.
Effect of Moisture Stress at Different Stages of Growth: II. Cytoplasmic Male‐sterile Corn1
Authors: Vincent G. B. , Woolley L. G.
Published: July 2010

The purpose of this study was to determine if the greater stress‐tolerance of corn plants with male‐sterile cytoplasm was due to their ability to extract, more moisture from the soil and retain it against atmospheric demand. If this is true, it would have significant impact on the water management and adaptation of the corn (Zea mays L.) plant.

An experiment was conducted on Colo silt loam soil in 1967 at Ames, Iowa to compare the effects of moisture stress at different stages of growth on Texas male‐sterile cytoplasm (cms) corn hybrids and their normal cytoplasm counterparts.

Grain yields were reduced significantly by a moisture stress imposed at anthesis. Hybrids with cms did not yield differently from their counterparts with normal cytoplasm, but cms hybrids maintained a higher level of leaf turgor when exposed to moisture stress at anthesis. The method used to establish equally severe intensities of stress was the withholding of irrigation water until a minimum level of 75% leaf turgidity was reached. Hybrids with normal cytoplasm withstood 1 day of serious stress during a 3‐day period, while hybrids with cms withstood 3 days of serious stress during a 10‐day period before reaching the minimum leaf turgidity.
Estimates of Optimum Plot Size and Shape from Uniformity Data in Burley Tobacco (Nicotiana tabacum L.)1
Authors: Gupton C. L.
Published: July 2010

To obtain estimates of optimum plot size and shape for burley tobacco (Nicotiana tabacum L.), we conducted uniformity trials during 1969 and 1970 at Greeneville, Tennessee, and during 1970 at Spring Hill, Tennessee. Each trial consisted of 3,000 plants which were subdivided into 600 basic units of 5 plants each. Data from each basic unit were recorded for yield of cured leaf, number of days to flower, number of harvestable leaves, plant height, and the length and width of the fifth leaf from the top of the plant.

Hatheway's “convenient plot size” and Smith's soil heterogeneity index methods were used to estimate optimum plot size. The results from Hatheway's method suggest that the greatest precision would be gained by minimizing the number of plants per plot and maximizing the number of replications in the experiment. Because 25 to 30 plants are required for visual evaluation of burley tobacco, it appears that a convenient plot size for yield and quality trials is 30 plants with the number of replications adjusted to the desired difference to be detected or the maximum number permitted by space and cost of production. We found that most other agronomic characters may be measured with acceptable precision on 10 to 20 plants per plot. For percent total alkaloids, precision is expected to increase rapidly with either an increased number of plants per plot or replications in the experiment. The optimum size of plot for yield computed by Smith's minimum cost procedure ranged from 9 to 179 plants. These results do not appear as useful as those from Hatheway's method.

Our data suggest that one‐row plots may be slightly better than two‐row plots. Taking into consideration the optimum number of plants per plot and shape, we concluded that single‐row plots containing 30 plants each are most desirable for yield and quality trials. Smaller one‐row plots with increased replication may be more efficient for obtaining genetic information relative to specific characters.
Establishment of Nine Forage Legumes in the Central Great Plains1
Authors: Townsend C. E. , McGinnies W. J.
Published: July 2010

Species used in range seedings must be relatively easy to establish in diverse environments. This study evaluated the ability of nine legumes to emerge and to become established from three depths of planting at five locations in the Central Great Plains. The nine species (Medicago sativa L., Onobrychis viciaefolia Scop., Vicia tenuifolia Roth., Coronilla varia L., A. stragalus cicer L., A, falcatus Lam., A. galegiformis L., A. striatus Nutt., and an unidentified Astragalus sp.) were seeded in the spring at 1.3‐, 2.5‐, and 3.8.cm depths. Seedling emergence counts were taken in early summer and stand ratings were made in late summer. Seedling emergence was best from the 1.3‐cm depth at all locations except one where the soil was very sandy and the best emergence was from the 2.5‐cm depth.

In general, V. tenuifolia, M. sativa, A. falcatus, and O. viciaefolia gave better seedling emergence than the other five species over all depths of planting at all locations. Although V. tenuifolia gave the best average emergence, it is probably not adapted to the sandy soils of the region, because by late summer most plants had died at the two locations with sandy soil. Emergence of A. cicer was relatively poor, but because of its rhizomatous characteristic, the stand of A. cicer was fair to good at the 1.3‐ and 2.5‐cm depths at most locations by late summer. The small‐seeded entries, A. striatus and Astragalus sp., were very sensitive to depth of planting. Seedling emergence of A. striatus was poor at most depths and locations. Emergence of Astragalus sp., however, was fair to excellent at most locations at the 1.3‐cm depth. Emergence of the large‐seeded species, A. galegiformis and C. varia, was poor at all locations.
A Versatile Small Plot Forage Harvester1
Authors: Smith R. R.
Published: July 2010

A versatile, small plot forage harvester developed at the University of Wisconsin is composed of basic, commercially available items such that the power unit (a standard garden tractor) can be used for other maintenance chores. The unit can be assembled and disassembled rapidly (10 min) and has hastened forage harvesting operation.
Influence of Seed Orientation on Bean Seedling Emergence1
Authors: Bowers S. A. , Hayden C. W.
Published: July 2010

Observation from an unrelated field bean experiment indicated that certain seed orientations might reduce emergence. Consequently, studies were initiated to determine if orientation variations occur in planting and if these variations influence emergence.

Orientation of bean seeds, dropped into both “V” and flat‐bottom furrows, were classified and tabulated. In “V” furrows almost all orientations were possible; 36% assumed the “lay‐flat” orientation. In the flat‐bottom furrow 85% of the beans were in the “lay‐flat” position. The influence of 11 different seed orientations on emergence was evaluated in greenhouse studies. With crusted soils seeds planted “hypocotyl end down” produced significantly less emerged seedlings (1% level) and a lower emergence rate. Orientation effects were observed to a lesser degree in noncrusted soils.

The adverse influence of “hypocotyl end down” orientations was attributed to seed rotation within the soil. For controlled plantings the “lay‐flat” orientation is recommended due to both its high frequency of occurrence and high emergence.
A Reliable and Inexpensive Soil Frost Gage1
Authors: Wilen B. O. , MacConnell W. P. , Michelson L. F.
Published: July 2010

Researchers have been interested in indirect methods of measuring soil frost penetration because direct methods require laborious digging that destroys the study area. Several indirect soil frost measuring techniques have been developed in the past. The use of commercially produced gypsum electrical resistance blocks has been established as one reliable technique. The research presented in this note will demonstrate that fabricated gypsum blocks are very accurate and durable enough to last several years in soil frost surveys in very acid soils.
Soxlet Glassware Technique for Nutrient Culture Studies1
Authors: Heilman M. D. , Anderson W. B.
Published: July 2010

Standard Soxlet extraction glassware was used as plant containers for nutrient culture experiments. The thimble reservoir served as the root chamber. Fresh nutrient solution was continuously exchanged in the root growth chamber by a self‐pumping technique utilizing air injected into the bulk solution for lifting the newly aerated solution to the root growth chamber.
A Computerized Personal Bibliographic Reference System1
Authors: Strand R. H. , Fribourg H. A.
Published: July 2010

A computer program for the creation and maintenance of an indexed personal bibliographic reference file is described. It is capable of providing an alphanumeric listing of all entries in a reference file, an alphabetic listing of all sources referenced, an alphabetic listing of all authors present, and an alphabetic index of all meaningful words (key words). In addition to the printed index for key word search, the system, which does not require sophisticated computer expertise, provides simple means for organizing, adding, or retrieving references. After the initial computer file creation, minimal computer access is required for updating the file.
Rate and Time of Nitrogen Application on Blueboy Wheat (Triticum aestivum L.)1
Authors: Clapp J. G.
Published: July 2010

The semi‐dwarf, stiff‐strawed soft winter wheat variety ‘Bineboy’ (Triticum aestivum L.) was released in 1965 by the North Carolina State University Agricultural Experiment Station. Presumably, its greater straw strength would allow producers to use higher rates of nitrogen without as much risk of lodging. Information was needed, however, on the nitrogen requirements of this new type of wheat and the most beneficial time for these applications.

Field experiments were conducted on two soil types (Davidson clay loam and Lynchburg fine sandy loam) for 2 years to determine the response of Bluehoy wheat to nitrogen rates of 56, 112, 168, and 224 kg/ha applied at seeding in October or partly in October at seeding (56 kg/ha) and partly in February as topdressing rates of 56, 112, and 168 kg/ha.

Applying all the nitrogen at seeding on the Davidson clay loam was just as effective for high grain yields and high test weight as the split applications. The 112 kg/ha applied in October (seeding) on this soil type was sufficient for maximum yields.

Grain yields were lower on the Lynchburg fine sandy loam soil for October applications than for February applications at nitrogen rates of 112 and 168 kg/ha. No difference in yield was obtained for the two dates at the highest rate of nitrogen (224 kg/ha).

Test weights were significantly lower both years when the nitrogen was applied in February on the Lynchburg fine sandy loam as compared to the same total rate applied at seeding. A similar trend was also found for the February nitrogen applications on the Davidson clay loam.

This study shows that Blueboy wheat producers can apply all of the nitrogen fertilizer to clay loams and fine sandy loam soils at the time of seeding rather than splitting the application into a small amount at seeding followed by a topdressing in February. A higher level of nitrogen fertilization will be required, however, to offset possible losses from leaching on soils with a sandy surface texture. On these soils producers must weigh the cost of using a higher nitrogen rate at seeding against the possibility of producing a lower‐quality wheat and the cost of an extra trip over the field in February when fields may be wet.
Utilization of Pelleted Phosphorus by Flax, Wheat, Rape, and Buckwheat from a Calcareous Soil1
Authors: Strong W. M. , Soper R. J.
Published: July 2010

Reaction zone root development and P absorption efficiency of roots of flax (Linum usitatissimum L. ‘Redwood’), wheat (Trlticum vulgate L. ‘Manitou’), rape (Brassica napus L. ‘Tanka’), and buckwheat (Fagopyrum esculentum Moench) have been contrasted in order to explain the large variability among them in utilizing P from pellets of KH2PO2 and K2HPO4 in a pot experiment. A large proportion of plant P was extracted from the pelleted applications by rape (40.8 to 57.6%) and buckwheat (33.1 to 55.5%). It is suggested that applied P utilization by rape was enhanced by e~tensive proliferation of its root system detected around points of application of fertilizer pellets. It is suggested for buckwheat, on the other hand, that its utilization of applied P was aided by the high efficiency of its root in absorbing P from high concentrations as indicated in absorption studies using excised roots. Relative to rape or buckwheat a much smaller proportion of plant P was extracted by flax (3.8 to 8.1%) and wheat (12.5 to 19.7%) from P applications. The poorer utilization of applied P by these two crops is considered due to the inability of their root systems to either proliferate extensively or to absorb P efficiently from high P concentrations.

It is reasoned that the greater P availability from a 40‐mg P application as KH2PO4 than from a 20‐mg P application as K2HPO4 was due to the higher water‐soluble P level in the reaction zone of the former application, with the two applications spread through the same soil volume. A given P application as K2HPO4 spread through a larger volume of calcareous soil than the same rate of P as KH2PO4. The water‐soluble P level, however, was lower in reaction zones of the former carrier. Thus, the effect of reaction zone size and of its watersoluble P level on the availability of P from KH2PO4, and K2HPO4 pellets offset one another, resulting in a similar availability of the two carriers to the four crops tested.