bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Time of Rhizomatous Propagation of a Temperate Zone Bamboo on Shoot Growth1
Authors: DeRigo H. T. , Hawley W. O.
Published: July 2010

An experiment was designed to evaluate the influence of time of rhizomatous propagation of a temperate zone bamboo, Phyllostachys viridis, on shoot growth. Propagules (rhizomes) were dug at random from the field at approximately monthly intervals from September 30, 1960 to September 5, 1961. Three nodal sections of the propagules were planted in the greenhouse and evaluated 6 weeks later for the percent of nodal buds producing shoots and for the resultant shoot growth.

There was no significant difference in mean shoot growth from rhizomes propagated during September, November, or December. December propagation favored smaller, but a greater number of shoots. Fifty percent greater shoot growth was realized from the propagation on February 21, 1961 than any earlier or later planting due to both the number of shoots produced and their average height per node.
Effect of Selected Soil Fertility Parameters on Soybean Yields1
Authors: Walker W. M. , Long O. H.
Published: July 2010

A soybean yield prediction equation was developed by fitting a regression model that included the variables lime, molybdenum, PK fertilizer, soil pH, soil phosphorus, soil potassium, and soybean yields at 5 sites over periods of 2 to 5 years for a total of 14 location‐years. A total of 352 yield observations with their associated lime‐fertilizer‐soil test levels were used. The regression analysis is described and the statistical significance of parameters in the regression model was measured.

The predicted optimum soil levels of pH, P, and K for maximum yields were determined. One set of isoquants was developed showing various combinations of soil pH values and tons of agricultural limestone required for selected yield levels; a second set was developed showing various combinations of soil P and K.
Influence of Triiodobenzoic Acid on Growth, Nodulation and Yields of Inoculated Soybeans1
Authors: Burton Joe C. , Curley R. L.
Published: July 2010

In field studies with two lines of inoculated soybeans, a spray application of 1 ounce per acre of triiodobenzoic acid (TIBA) during the early blossom period reduced plant height by 16%, increased branching, shortened leaf petioles, and produced a conical‐shaped row profile. Pod numbers were increased by 4 to 15% and were concentrated on the lower branches; lodging was minimal. With 36‐inch rows, TIBA had no effect on yield.

Nodulation of the TIBA treated plants was equal to that of untreated plants. No adverse effect on symbiotic nitrogen fixation was noted. Inoculation produced significant yield increases on both untreated and TIBA treated plants. With TIBA, inoculation increased yield only when plants received a side‐dressing of fertilizer nitrogen in mid‐August. Apparently the nodules were unable to supply the demand of TIBA treated plants for nitrogen during the heavy podding stage.
Comparison of Calcium and Boron Deficiencies of the Peanut I. Physiological and Yield Differences1
Authors: Harris Henry C. , Brolmann John B.
Published: July 2010

Comparisons of calcium and boron deficiency and normal peanuts (Arachis hypogaea L. var. “Florigiant”) were made from plants grown to maturity on soils supplying inadequate and adequate (with fertilization) levels of these nutrients. The characteristics of boron and calcium deficiencies were distinctive and strikingly different. Boron deficiency seemed to affect all parts of the plant. It changed foliage characteristics, flowering pattern, and usually increased shoot and root yields. However, the deficiency decreased fruit yield and caused poor quality of fruit. In contrast, calcium deficiency seemed to affect only fruit yield and quality. Without calcium the yield usually was lower and the quality of the seed poorer.
Forage and Nitrogen Production by Subclover‐Grass and Nitrogen‐fertilized California Grassland1
Authors: Jones Milton B.
Published: July 2010

A 3‐year study was made with resident annual grasses and broadleaf herbs in 3 management systems and 8 fertility treatments.

In a moisture‐deficient year (rains commencing late in November and ending in March), stands of subclover‐grass produced forage yields equivalent to those from California annual‐type grasslands fertilized with 45 to 90 kg N/ha. Uptake of N by subclover was equivalent to 90 to 179 kg N/ha in this dry year. In a moisture‐adequate year (rains commencing in early October and ending in May), subclover‐grass stands produced more forage than did resident grasslands fertilized with 179 kg N/ha. In this same year, uptake of N by subclover‐grass was about double that by grass fertilized with 179 kg N/ha. Nitrogen fertilization made its most valuable contribution to forage production during the winter period. Second and third year stands of subclover also increased production early in the season but made the greatest gains in April and May.
Effect of Soil pH, Drainage, and Fertility on Growth, Survival, and Element Content of Crownvetch, Coronilla varia L.1
Authors: McKee Guy W. , Langille Allan R.
Published: July 2010

Field observations and greenhouse studies indicated that crownvetch, Coronilla varia L., required good to excellent drainage, a pH of 6.5 to 7.0, and high levels of P, K, Ca, and Mg for rapid seedling growth and stand persistence. Crownvetch compared favorably with ‘Mansheld’ birdsfoot trefoil in rate of seedling growth. While minor cultivar differences in relative top and root growth were noted, ‘Chemun’, ‘Emerald,’ and ‘Penngih’ crownvetch all produced dense vegetative canopies 2 to 3 months after seeding. On 42 highway slopes successfully seeded to crownvetch in 27 Pennsylvania counties, areas of poor or zero crownvetch cover on upper and lower portions of the slope were more closely associated with limiting physical conditions, poor drainage, or extreme desiccation, than with inadequate fertility or low pH.
Pathways of Nitrogen Transfer in Some Tropical Legume‐Grass Associations1
Authors: Whitney A. S. , Kanehiro Y.
Published: July 2010

Three ways by which legumes release nitrogen for possible transfer to an associated grass were evaluated in greenhouse experiments utilizing Desmodium intortum (Mill.) Urb., D. canum (Gmel.) Schintz & Thellung, and Centrosema pubescens Benth. Legume root systems, growing in cinders and perfused with nitrogen‐free solutions, normally released only trace amounts of nitrogen to the solutions. However, immediatedly after the plants were cut back marked increases in the release of ammonium and amino nitrogen were observed. When the root systems of nitrogen‐starved grass plants (Digitaria decumbens Stent) were perfused in series with the legume roots, significant nitrogen transfer occurred from the more vigorous legume plants, especially after cutting back the legumes.

Release of soluble nitrogen from legume leaves due to leaching was studied by shaking excised leaves of varying ages in distilled water. The amounts of soluble nitrogen extracted were always small, but rapidly expanding leaves, yellowing leaves, and shaded leaves contained much higher levels of extractable amino nitrogen than did other classes of leaves.

Leaf fall accounted for significant nitrogen losses from D. intortum and C. pubescens plants allowed to shed mature leaves over a period of time, thus providing a third source of transferable nitrogen.

The combined effects of root losses, leaching of leaves, and leaf fall provide an adequate explanation for the nitrogen transfer observed in an earlier small plot experiment.
Trifluralin Behavior in Soil. II. Volatilization as Influenced by Concentration, Time, Soil Moisture Content, and Placement1
Authors: Bardsley C. E. , Savage K. E. , Walker J. C.
Published: July 2010

Vapor loss of trifluralin from water was found to be proportional to concentration, with losses being greater uring a 12‐hour period than during an 8‐hour period.

Vapor losses were greater from a soil at maximum retentive capacity than from a soil at field capacity when the trifluralin was applied at equal rates to the soil surface. This is attributed to a greater proportion of free liquid available for vapor loss (high moisture), more trifluralin in the liquid due to the solubility effect, and to competition of water with the herbicide for adsorption sites.

Placement of trifluralin 1.27 cm (½ inch) below the soil surface resulted in a very low vapor loss of the same magnitude for both moisture regimes.

The experiments were run in a vapor‐trap apparatus involving still air. It is presumed that air movement would accelerate vapor losses of this compound under certain conditions.
Weed Control Methods for Kinkaoil, Kenaf, and Sunn Crotalaria1
Authors: Burnside O. C. , Williams J. H.
Published: July 2010

These studies deal with mechanical, cultural, and chemical weed control methods that will selectively control weeds in kinkaoil (Vernonia anthelmintica Willd.), kenaf (Hibiscus cannabinus L.), and sunn crotalaria (Crotalaria juncea L.). Sunn crotalaria was most competitive, followed closely by kenaf, with kinkaoil being a very poor competitor to the annual weeds present. The most selective herbicide for these crops was α,α,α,‐trifluro‐2,6‐dinitro‐N,N‐dipropyl‐p‐toluidine (trifluralin). The crops can be ranked from most to least tolerant to trifluralin as follows: kenaf, sunn crotalaria, and kinkaoil. A combination of cultivation plus trifluralin gave the most effective and consistent weed control in the seed crop, kinkaoil, and the pulp crops, kenaf and sunn crotalaria.
Response of Corn to White and Black Ground Covers1
Authors: Aase J. K. , Kemper W. D. , Danielson R. E.
Published: July 2010

Corn was grown in rows between sloping concrete slabs painted either black or white. Grain yields were highest for the black concrete treatment. Transpiration was increased about 40% by the white concrete treatment.

With white surfaces, leaf temperatures were about 1 C higher and reflected radiation was five to six times greater compared to black surfaces. Corn leaves sampled adjacent to black concrete contained 40% more chlorophyll than corn leaves sampled adjacent to white concrete.
Extraction of Chlorinated Hydrocarbon Insecticides from Soils1
Authors: Pionke H. B. , Chesters G. , Armstrong D. E.
Published: July 2010

A Soxhlet procedure is described for the quantitative extraction from soils of γ‐BHC, aldrin, dieldrin, heptachlor epoxide, p,p′‐DDD, p,p′‐DDT, and methoxychlor in mixtures containing all these insecticides. On prolonged equilibration (30 days) of the insecticides with soil, indicatons of γ‐BHC and aldrin degradation were noted. When soils were incubated in sealed containers to restrict O2 availability the rates of γ‐BHC and aldrin degradation were enhanced. No effect of soil H2O content at the time of incubation or extraction on the efficiency of the extraction procedure was found.
Varietal Tolerance of Tobacco to Ozone Dose Rate
Authors: Menser H. A. , Hodges G. H.
Published: July 2010

We determined the relative degree of ozone injury to genetically susceptible and resistant tobacco (Nicotiana tabacum L.) plants in studies of ozone tolerance. Essentially equal ozone doses derived from three ozone concentrations and nine exposure intervals were imposed on three tobacco varieties in fumigation experiments. Length of exposure determined relative injury at 0.10 ppm, but ozone concentration controlled injury when plants were exposed at 0.20 and 0.30 ppm. Ozone‐resistant cv. ‘Bel‐B’ sustained less than 10% total injury from a 0.15 ppmhr dose given at any of the three ozone concentrations. A 0.15 ppmhr dose, however, caused significantly greater injury to ozone‐susceptible cv. ‘Bel‐W3’ at the two higher ozone concentrations. Ozone caused almost 40% leaf injury to Bel‐B when we exposed plants to a 0.30 ppmhr dose at 0.20 and 0.30 ppm, but total injury remained near 10% when the 0.30 ppmhr dose was given at 0.10 ppm. Results indicate that varietal response to ozone is controlled by exposure interval and concentration rather than ozone concentration independently. Ozone dose rate affected the size of fleck lesions displayed by Bel‐W3. Leaves exposed for 6 hr at 0.10 ppm developed flecks four to six times larger than the flecks obtained after 1 hour at 0.30 ppm.
Adaptation of a Linear Transducer for Measuring Leaf Thickness1
Authors: Heilman M. D. , Gonzalez C. L. , Swanson W. A. , Rippert W. J.
Published: July 2010

A linear displacement transducer has been successfully adapted for determining leaf thickness. Leaf thicknesses were determined on young and mature leaves of seven plant species. Measured differences in leaf thickness of cotton following treatment with a growth regulator are also reported.
Effect of Varying Levels of Soil and Fertilizer Phosphorus and Soil Temperature on the Growth and Nutrient Content of Bromegrass and Reed Canarygrass1
Authors: Read D. W. L. , Ashford R.
Published: July 2010

Bromegrass and reed canarygrass responded differently to soil temperature, available soil P, and phosphatic fertilizer when grown in a growth chamber. Bromegrass yielded less than reed canarygrass but contained more N and P in the forage. The difference in P content was greatest on soils with medium levels of P and was very small on soils with either high or low levels of P. The yield of reed canarygrass was reduced more by lower temperature than the yield of bromegrass. The study was conducted at three soil temperatures, on three soils differing in levels of available P and applications of four rates of phosphatic fertilizer.
Drainage with Perforated Plastic Tubing1
Authors: Klock G. O. , Boersma L. , Watts D. G. , Brooks R. H.
Published: July 2010

The feasibility of placing drains at shallow depths and close together to improve drainage conditions on a planosol was evaluated. Field lysimeters were obtained by surrounding soil blocks with vertical sheets of heavy plastic penetrating well into the impermeable subsoil. Perforated plastic tubing placed 22.5 feet (approx. 6.9 m) apart at a depth of 20 inches (approx. 51 cm) provided adequate drainage. Dupuit alfalfa yielded better than 10 T/A dry matter. Manganese levels were below concentrations considered toxic. When a spacing of 45.0 feet (approx. 13.7 m) was used, the alfalfa yields were greatly reduced, and the manganese concentrations were well above levels considered toxic.
Effect of Plant Age and Nitrogen Fertilization on the Chemical Composition and In Vitro Cellulose Digestibility of Tropical Grasses1
Authors: Gomide J. A. , Noller C. H. , Mott G. O. , Conrad J. H. , Hill D. L.
Published: July 2010

This study was conducted in the state of Minas Gerais, Brazil, on a sandy loam soil low in fertility and a pH of 5.1. The mean monthly rainfall ranged from near zero during the 5‐ to 6‐month winter dry season and up to 330 mm in the mid‐summer wet season. The percentages of dry matter, crude protein, cellulose, crude fiber, and in vitro digestibility were determined on six tropical grass species: Melinis minutiflora Beauv., Digitaria decumbens Stent., Pennisetum purpureum Schum., Pennisetum clandestinum Hochst, Cynodon dactylon Pers., and Panicum maximum Jacq. var. Gongylodes Doell. Samples were taken with advancing age every 4 weeks beginning at the outset of the wet summer seasons in each of 2 years, 1964 and 1965, and each sampling period continued for 36 weeks. Lime, N, P, and K were applied as a basal application. In addition, N was applied each year at the rates of 0, 100, and 200 kg/ha. The increase in dry matter percentage was linear over time with an increase of 21.2 to 51.4% for all grasses. P. purpureum had the lowest dry matter percentage and C. dactylon the highest. Application of N fertilizer resulted in decreased dry matter percentage during the early growth stages but not at the more mature stages. The crude fiber percentage increased with age and the in vitro cellulose digestibility decreased. The cellulose percentage of three of the grasses increased with age while the other three remained almost constant during the sampling period.
Effect of Time and Method of Nitrogen Application and Source of Nitrogen on the Yield and Nitrogen Content of Corn (Zea mays L.)1
Authors: Stevenson C. K. , Baldwin C. S.
Published: July 2010

Fall plowdown, spring preplant, and side‐dress applications of nitrogen were compared in field experiments on Brookston clay, Brookston clay loam, and Haldimand silt loam soils. Ammonium nitrate, urea, and anhydrous ammonia were compared at 56, 112, 168, and 224 kg N/ha. Spring application (preplant or side‐dress) produced higher grain yields than fall application in all experiments regardless of the rate of nitrogen applied. Preplanting the nitrogen was as effective in increasing grain yield as the side‐dress method. Yield results with fall‐applied nitrogen were poorer on the clay soil than the loam soils. Spring application of nitrogen gave 370 to 2,610 kg/ha higher yield of corn grain than fall application on clay soils, and 200 to 1160 kg/ha higher yield of corn grain on the loam soils. No rate of nitrogen applied in the fall was found that would give the same yield as the optimum rate applied in the spring. The three nitrogen materials gave similar results whether applied in the fall or in the spring.

The nitrogen content of the grain varied with the time and method of application of nitrogen. Grain from plots that received nitrogen in the fall was markedly lower in percent nitrogen than grain from plots that received nitrogen in the spring.
Stand and Early Growth of Orchardgrass and Red Clover Seeded after No‐Tillage Corn1
Authors: Moschler W. W. , Jones G. D. , Shear G. M.
Published: July 2010

Increased soil moisture, pH, organic matter, and available phosphorus and calcium in the 0 to 5‐cm soil layer were found after corn (Zea mays L.) was grown by the notillage method rather than by the conventional method. Orchardgrass (Dactylis glomerata L.)—red clover (Trifolium pratense L.) mixtures seeded in early spring after no‐tillage corn gave better stands and better early growth than when seeded after conventionally tilled corn.
Evaluation of Cotton Response to Rates, Sources, and Timing of Nitrogen Application by Petiole Analysis1
Authors: Amer Fathi , Abuamin Hoda
Published: July 2010

Three experiments were conducted on a calcareous clay loam soil to determine the relationship between nitratenitrogen content of cotton (Gossypium barbadense) petiole and yield; and to employ the petiole analysis technique for evaluation of calcium nitrate, ammonium nitrate, and urea as N sources and evaluation of timing of N application. Increase in cotton yield associated with unit increment of petiole nitrate was proportional to the decrement from the maximum and the data were fitted to the exponential equation of Spillman. Cotton yield was not affected by N source and time of application, but petiole nitrate was sensitive to both. Calcium nitrate was the best fertilizer and the availability coefficients of N in ammonium nitrate and urea as a fraction of that in calcium nitrate were 0.714 and 0.511, respectively. Splitting the applied N in thirds proved superior to a split into two applications or to a single total application, and the availability coefficients ratios were 20.889, and 0.566, respectively.
Photosynthetic Light Sensor for Measurements in Plant Canopies1
Authors: Norman J. M. , Tanner C. B. , Thurtell G. W.
Published: July 2010

A photosynthetic light sensor is described, which is based on experimental evidence that absorbed quanta at various wavelengths in the visible region (400‐700 nm) are nearly equally effective in initiating photosynthesis. Silicon photovoltaic cells are used as light detectors and their spectral response tailorded with Wratten filters to provide quantum response. A sharp near‐infrared cutoff is obtained by subtracting the signal of a cell sensing only the infrared from the signal of the cell sensing both the visible and infrared wavelengths. This pair of cells is then placed under heat absorbing glass to further reduce their differences. The differenced current signals from the cells are fed directly into an operational amplifier designed for current amplification. A fair cosine rtsponse is obtained by using a flat piece of diffusing plastic as the uppermost part of the sensor. Calculations and measurements are made to estimate errors resulting from imperfections in spectral tailoring and cosine correction.
Recovery of Differentially Placed NO3‐N in a Silt Loam Soil by Five Crops1
Authors: Dancer W.S. , Peterson L.A.
Published: July 2010

Placement of NO3‐N at soils depths of 8, 23, 38, 53, and 69 cm was accomplished by an injection method with minimum disturbance to plant roots and to the soil profile. Utilization of the differentially placed NO3‐N by five crops for two cropping seasons indicated that these crops varied in their ability to recover the NO3‐N. Lima beans (Phaseolus lunatus L.) and green beans (Phaseolus vulgaris L.) obtained most of their N from the plow layer; while corn (Zea mays L.), tobacco (Nicotiana tabacum L.), and red beets (Beta vulgaris L.) recovered NO3‐N equally well from either the plow layer or the subsoil.
Molybdenum Response of Soybeans (Glycine max (L.) Merrill) in Iowa1
Authors: DeMooy cornelis J.
Published: July 2010

Highly significant yield responses of soybeans were obtained for the first time from molybdenum treatment of seed at planting on several Iowa soils during 1968. Yields were raised 269 to 336 kg/ha (4 to 5 bu/acre)in response to 93 g molybdenum per ha at two sites in the soil pH range from 5.8 to 6.7. No responses occurred on some other soils in the same pH range. On calcareous Webster soil, molybdenum treatment resulted in a significant reduction in yield of 226 kg/ha. Yield effects were not accompanied by significant changes in molybdenum content of the leaves at bloom.
Effect of Adsorbed Cations on Phosphorus Absorption by Various Plant Species1
Authors: Franklin R. E.
Published: July 2010

P uptake by excised roots of 10 different plant species was found to be stimulated by a short pretreatment with polyvalent cations, or by raising the ionic strength of the absorbing solution.

The pretreatment consisted of a l‐min rinse with 10−3 N chloride salt solutions prior to exposure to 2 × 10−5 M KH2PO4. Also, the root CEC was estimated by isotopic exchange using a labeled CaCl2 solution. The stimulation of P uptake by the polyvalent cation pretreatments was significantly correlated with the amount of P taken up by the control and the root cation exchange capacities. The results supported the hypothesis that the cell wall can act act as a negatively charged membrane regulating P uptake.
Ethanol Concentration in Tomato Plants during Soil Flooding1
Authors: Bolton E. F. , Erickson A. E.
Published: July 2010

Tomato plants were studied to assess the potential value of ethanol accumulation in plant tissue as a measure of O2 stress resulting from short periods of soil flooding. Ethanol concentration in xylem exudate was markedly associated with air temperature, and to a lesser extent with light intensity and soil temperature under conditions of flooding. Field flooding results agreed closely with simulated environments.

A small amount of ethanol was eliminated by transpiration from flooded tomato plants under environmental conditions that favored accumulation. A slightly higher amount of ethanol was excreted from the roots.

Ethanol in tomato plant samples appeared to indicate the intensity of O2 deficiency during flooding by reflecting both soil O2 supply and environmental effects, and could serve as a useful indicator in relating tomato plant injury to flooded conditions.
Effects of Air Pollutants on Burley Tobacco Cultivars
Authors: Menser H. A. , Hodges G. H.
Published: July 2010

Nine burley tobacco (Nicotiana tabacum L.) varieties were tested for susceptibility to air pollutants in fumigation chamber and field experiments. Ozone administered for short intervals (1.0 and 1.5 hours) at relatively high concentrations (30.0 and 20.0 pphm, respectively) caused significantly more leaf injury than when used for a longer period (3.0 hours) at a lower concentration (10.0 pphm). These tendencies were apparent even though total ozone dosages were about equal. At the lowest rate, ozone caused the most injury to ‘Burley 2’ and ‘Ky 16,’ and the least injury to ‘Burley 49’ and ‘Ky 9.’ Cultivars exhibited much smaller differences in degree of leaf injury when ozone was given at high as compared to low concentrations. Burley 2 and Ky 9 continued to be susceptible and tolerant, respectively, at the high rates. Response of the nine varieties to low concentration mixtures of ozone and sulfur dioxide revealed: (1) the two gases acted synergistically to cause injury; and (2) Burley 21 and Burley 49 reversed positions of susceptibility to mixed gases as compared to injury by ozone.

In the field weather fleck was more severe on Burley 2, Burley 21, Ky 9 and Ky 16 than on ‘Burley llB’ and ‘Burley 37.’ The varieties that showed the greatest fleck tolerance were Burley 49 and ‘Ky 12.’ Ozone, the primary cause of weather fleck, reached a phytotoxic level of 5.0 pphm (Mast 724‐1) on 20 dates during July. Highest concentration recorded was 12.0 pphm on July 24.

All varieties exposed to pollutants in the chamber displayed identical symptoms. Ozone at low dosages caused tiny, bleached stipples or flecks to appear on the upper leaf surface. Ozone and sulfur dioxide mixtures induced upper surface fleck‐like markings very similar to (but a little larger than) ozone lesions. Field symptoms of weather fleck consisted of characteristic ozone flecking on Burley 2, Burley 11B, Ky 9, Ky 12, and Ky 16 and biracial necrotic lesions (2.0 to 3.0 mm) on Burley 37, Burley 49, and ‘Ky 35.’
Yield and Leaf Area of Type 41, Pennsylvania Broadleaf, Tobacco as Affected by Variety and Plant Population1
Authors: Yocum John O. , McKee Guy W.
Published: July 2010

Studies in southeastern Pennsylvania utilizing two recommended varieties of Type 41, Pennsylvania broadleaf, tobacco indicated that conventional plant populations (13,000 to 15,000 per ha) may be too low for optimum yield of cured leaf. While leaf area per plant decreased as population increased, the decrease was more than compensated for by the increased number of plants. In 1965, nearly normal as regards precipitation, leaf area indices (leaf area/unit land area) just prior to harvest were, respectively, 5.54, 6.14, and 8.10 for 10,500, 14,600, and 20,900 plants/ha. Leaves were more erect at the high population than at the other two populations studied. In 1966, a relatively dry year with precipitation 56% of normal, leaf area indices were, respectively, 2.30, 3.68, and 5.32 for 9,000, 16,100, and 24,600 plants/ha. At all populations, leaves were less erect in 1966 than in 1965. Leaf quality was not significantly affected by plant population. Both total yield of cured leaf and gross cash return increased as population increased.
A Comparison of Three Methods for Estimating Root Length1
Authors: Reicosky D. C. , Millington R. J. , Peters D. B.
Published: July 2010

The root system from a 10‐week‐old soybean plant was washed free of soil and total root length estimated by three different techniques. Direct measurements were first made on fresh root samples and later, from projected black and white photograph transparencies of the fresh material, further estimates of root length were obtained by two additional methods. The first of these was the opisometer method which, in essence, requires tracing over the entire length of root in the sample. The second method, developed by Newman, requires counting of the number of intersections between the randomly diffused roots and a grid line of known length.

The coefficient of variation for means of three estimates by each method showed that there was little difference in precision between methods. However, with Newman's method, an estimate was made in 1.0 hour compared with 5.0 hours for the direct method and 1.5 hours for the opisometer method.
Nitrate Accumulation in Smooth Bromegrass (Bromus inermis, Leyss.): I. Effects of Applied N, P, and K1
Authors: Vanderlip R. L. , Pesek John
Published: July 2010

The NO3−N content of smooth bromegrass (Bromus inermis, Leyss.) was determined for two N, P, and K fertilizer experiments in each of 2 years (1962 and 1963) on Shelby silt loam in south‐central Iowa to determine the extent to which nitrate would accumulate in this species and the effects of these nutrients on accumulation. Nitrate‐nitrogen content of the forage was determined by steam distillation on samples taken periodically throughout the growing season and related to rates of applied N, P, and K and time after fertilization and time after clipping by multiple regression techniques. All three elements affected the NO3−N content; however, the effects varied among site‐years. The effects were interrelated as shown by the large number of significant interactions. Time after application and time after clipping also were important in determining the NOa‐N content. A large number of applied element by time variable interactions were found significant indicating the dependence of the applied fertilizer effects upon either time after application or time after clipping.
Speeding the Drying of Alfalfa Hay with Fusicoccin1
Authors: Turner Neil C.
Published: July 2010

Fusicoccin, a wilt toxin produced by the fungus Fusicoccum amygdali Del., was sprayed onto alfalfa (Medicago sativa L.) 3 hours before cutting. Under constant environmental condition in the laboratory, the shoots treated with 10‐5 M fusicoccin solution dried to a moisture content of 40% (dry weight basis) in half the time of the controls. In the field the drying time to a moisture content of 22% (dry weight basis) was reduced from 54 to 46 hours; thus the hay could be safely stored after 3 days instead of 4 days. The fusicoccin also reduced losses by respiration. Rainfall probabilities for Connecticut suggest that use of fusicoccin would prevent damage by rain on 15% of the days suitable for haymaking. The results also suggest that fusicoccin will be more beneficial when drying conditions are poor.
Effect of Soil Temperature on Rate of Barley Development and Nutrition1
Authors: Power J. F. , Grunes D. L. , Reichman G. A. , Willis W. O.
Published: July 2010

Results from this experiment indicate that for barley plants harvested at equal stages of morphological development, low soil temperatures per se are not deterimental to growth. Barley was grown to maturity in a growth room at soil temperatures of 9, 15.5, and 22C with either 9 or 44 ppm fertilizer phosphorus. At a given stage of plant development, dry matter production and N and P uptake were usually lowest at a soil temperature of 22C. Dry weights, grain yields, and nutrient uptake at 9C usually equalled or exceeded those at 15.5C — the soil temperature considered optimum for barely production. At 9C growth was very slow until the barley developed to the 4‐leaf stage, but thereafter approximated the growth rate at higher soil temperatures. Nutrient uptake and water use data suggest that the slow initial growth rate at 9C may be due to restricted nutrient translocation from roots to tops, rather than to reduced rate of uptake of water or nutrients. Soil temperatures affected both the growth rate and water use rate, resulting in only a small effect of soil temperature on total water used to reach a given growth stage.
Effects of Weather, Nitrogen and Population on Corn Yield Response1
Authors: Bondavalli Bruno , Colyer Dale , Kroth Earl M.
Published: July 2010

The effects of rainfall and temperature on the yield and response of corn (Zea Mays L.) to plant population and nitrogen application rates were estimated from experimental data collected at three Missouri sites over an 8‐year period. The growing season from May through August was divided into 15‐day periods to test for the effect of rainfall and temperature on corn response to several nitrogen and planting rates. Preseason rainfall and total rainfall during the growing season also were included as variables. Both temperature and rainfall variables affected yield significantly with the first half of August being most significant with respect to rainfall and the second half of May with respect to temperature. The economic optimum inputs at the mean rainfall for the growing season were 41,850 plants/ha and 163 kg N/ha. The optimal input of nitrogen was relatively sensitive to the rainfall level with the optimal population level less affected.
A Combination Belt, Cone and Vacuum Seeder for Experimental Cereal Plots1
Authors: Dewey W. G. , Agathangelides D. , Rich H.
Published: July 2010

A drill is described which combines the desirable features of belt, cone, and vacuum seeders. The drill and tractor unit is easily portable in the back of a pickup truck. We are using the drill primarily to seed wheat and barley nurseries, but it could be used equally well for a variety of other crops.
The Effects of Potassium on Ammonium Nutrition of Tomato (Lycopersicon esculentum Mill.)1
Authors: Ajayi O. , Maynard D. N. , Barker A. V.
Published: July 2010

Tomato plants (Lycopersicon esculentum Mill.) grown in pot culture in the greenhouse were easily injured by continuous, prolonged application of (NH4)2SO4. When an equivalent amount of K was supplied with the NH4, plant injury due to excessive NH4 was prevented. The presence of K in the NH4 culture system enhanced growth and restricted total N and NH4‐N accumulation. The magnitude of the restriction of N constituents suggests that the ameliorating K effect was due in part to a K:NH4 competition for uptake but principally to the enhancement of NH4 assimilation.
Preparation of and Plant Response to a Yellow Phosphorous‐Ammonia Solution1
Authors: Cressman H. K. , Richards G. E. , Edwards T. A.
Published: July 2010

Yellow phosphorus was dissolved in liquid anhydrous NH3 and evaluated as a P source for corn (Zea mays L.) and ryegrass (Lolium multiflorum L.). The composition was phytotoxic and the P was of low plant availability. When the solution was incubated in soil prior to seeding corn, toxicity was less pronounced. The residue following evaporation of NH3 was also phytotoxic. In a short term study on a fine‐textured soil, corn failed to respond to either toxic compounds or orthophosphate present in the zone of NH3 injection.
Influence of Date of Planting on the Yield of Kenaf (Hibiscus cannabinus, L.)1
Authors: Whiteley Eli L.
Published: July 2010

abstract

Kenaf (Hibiscus cannabinus L.) is a promising new annual source of pulp for industry. Dry matter yields which are sufficiently high to compete with existing crops in Texas are needed. Adaptation and cultural studies were undertaken to determine levels of productivity that can be expected in the eastern part of the state. Some varieties of kenaf are classified as daylength insensitive and should produce high yields from early planting dates. However, in this test the variety × planting interaction within years was not significant. The earliest planting date produced the highest yield in only one (1967) of the 3 years of the study. Moisture and light influenced yields as much as date of planting.

Average dry mater yields of 5.17 to 14.29 tons/ha were obtained over the 3 years of tests. Yields in excess of 12 tons/ha were obtained each year of the tests. Differences in production potential of available varieties were obtained. Yields of some of the varieties were quite different from year to year. 'Guatemala 45' produced 6.52 tons/ha in 1968 and 14.67 tons/ha in 1969.
Black Layer Development in Corn1
Authors: Rench W. Eugene , Shaw Robert H.
Published: July 2010

A study was made to determine the relationships between visual kernel black layer development, dry matter accumulation, and moisture level.

Kernels taken from the same plants every 3 days were rated as to their visual black layer phase of development from plants approaching maturity. Remaining kernels from the same sample were dried and evaluated for dry matter and moisture content.

Peak dry matter accumulation coincided with initial occurrence of visual black layer formation. Weight lost by kernels from initial visual black layer development to completed black layer development was significant.

Kernel moisture declined significantly during black layer development. Black layer mature kernels had moisture levels that differed statistically between varieties and within a variety planted at different dates.
Response of Alfalfa Varieties to Different Water Table Depths at Various Stages of Growth1
Authors: Rai S. D. , Miller D. A. , Hittle C. N.
Published: July 2010

Two varieties of alfalfa, Medicago sativa L., ‘Kentucky Syn. Z1’ and ‘Narragansett,’ were grown in glazed tiles 90 cm deep with water tables of 15, 30, and 45 cm from the surface. When the water‐tables were raised immediately after the harvest, the dry matter yield was drastically reduced in both varieties. No significant yield difference was found when the treatments were applied 14 or 28 days after harvest. The highest yield was obtained when water table was held 45 cm from the surface and when applied 14 or 28 days after harvest.
Overseeding Winter Annual Grasses in Sericea Lespedeza1
Authors: Hoveland C. S. , Carden E. L.
Published: July 2010

Forage yields of rye (Secale cereale L.), rescue (Bromus catharticus Vahl.) and ryegrass (Lolium multiflorum Lam.) seeded annually for three years on Serala sericea (Lespedeza cuneata (Dumont) G. Don) were compared.

Rye furnished 1,400 kg/ha of dry forage by March 20 while rescue and ryegrass produced less than 250 kg/ha by the same date. Rye extended the productive season by about 2 months and increased total annual yields 2,000 kg/ha over the 6,600 kg/ha produced by sericea alone. Sericea growth in spring was not reduced by rye, but it was reduced by rescue and ryegrass. None of the species reduced stands of sericea.
Rapid Transectioning of Plant Leaves1
Authors: Gausman Harold W. , Schupp Marcia
Published: July 2010

Photomicrographs of oleander leaf transections (Nerium oleander L.) were taken within 15 min after leaves were excised from the plant and sectioned with a Hooker plant microtome. This rapid procedure, compared with the approximately 20‐day conventional method involving tissue fixation, paraffin embedding, staining, and sectioning with a rotary microtome, apparently gave a truer representation of the leaf mesophyll arrangement (particularly size of intercellular spaces), and usually gave better definition to leaf cuticles, druses, multiple epidermal layers, trichomes, and stomates within stomatal crypts. Variability among leaf sections, however, was greater for the Hooker than for the conventional method. Discounting some disadvantages, the rapid procedure should be useful in a portable field laboratory for “on‐the‐spot” sectioning and photomicrographic recording of plant tissue development.
Soil Heating Studies with Cool Season Turfgrasses. III. Methods for the Establishment of Turf with Seed and Sod during the Winter1
Authors: Ledeboer F. B. , Skogley C. R. , McKiel C. G.
Published: July 2010

Turf establishment methods using seed and sod transplants were investigated on electrically heated soil during two winters. Five turfgrass species were seeded on March 3, 1968, in plots maintained at 4.4, 10.0 and 15.5 C soil temperatures. Plots were half covered with a black polypropylene screen giving 55% shade. Treatments produced similar responses in all grasses. Germination time was reduced by increasing soil temperature and adding cover. Response differences between 10 and 15 C were smaller than between 4 and l0 C. ‘Manhattan’ perennial ryegrass germinated first under all treatments and established most rapidly. Following germination, cover influenced grass development more than did soil temperature. Regardless of soil temperature, grasses in open plots developed slowly until mid April. During early grass establishment, cover effect was magnified by increased soil temperatures.

‘Merion’ Ky. bluegrass sod rooted better at 8 C than at 6 C. Rooting was inhibited by shade, but foliar growth increased. Medium shade (55%) did not cause serious rooting inhibition. Shade effects were increased by increasing temperatures. N treatments produced better rooting in open plots, but under shade, N decreased rooting. Practically no rooting occurred under 73% shade.
Internal Water Status and Water Transport in Seed Onion Plants1
Authors: Millar A. A. , Gardner W. R. , Goltz S. M.
Published: July 2010

Water potential, transpiration rate, and stomatal resistance of the various parts of the onion (Allium cepa L.) plant were measured under field and controlled conditions.

Water potentials of florets and pedicels were always lower than leaf water potentials. Water potential difference between the florets and the soil of as much as —9 bars were found. The greatest drop in water potential was found between the flowers and the upper part of the seed stalk. These differences in water potential were found even when plants were growing in soil well supplied with water.

Transpiration rates of the leaves were the greatest of all plant parts, the seed stalk next (about 15 to 20% of the flux density from the leaves), and the umbel lowest, representing a very small fraction of the total. Stomatal resistance of the leaves was at all times lower than seed stalk stomatal resistances. An almost on‐off stomatal behavior by which the onion plant regulates its transpiration was found to operate in a narrow range of leaf water potential, —3 to —7 bars.

The relation between flux density and water potential drop was found to be highly nonlinear in plants growing in different soils and under a wide range of soil water potential and environmental conditions. Impedance to water flow in the seed stalk was 5 to 8 times greater than in the leaves. For the same conditions potential drop between soil and root surface was less than 5 cm of water.
Influence of Mechanical Impedance on Rice Seedling Root Growth1
Authors: Kar S. , Varade S. B.
Published: July 2010

The influence of bulk density and the strength of lateritic sandy loam soil of Kharagpur on root growth of rice (Oryza saliva) seedlings was studied under controlled conditions. Rice (‘Taichung Native‐1’) seedlings were grown for 14 days in soils compacted to different bulk densities in painted galvanized iron cylinders. Water and nutrient requirements were met through nutrient solution.

Maximum rice root growth and penetration occurred when the soil bulk density and penetration pressure were 1.6 g cm− 3 and 36 kg cm− 2, respectively. Lower bulk densities resulted in poor root growth, whereas subsequent increase in bulk densities above 1.6 g cm−3 decreased root growth. A penetration pressure of 72 kg cm− 2 was found to be critical for rice root penetration and growth. Rice root growth under saturated conditions is more significantly related to bulk density than to strength of the soil.
Preservation of Soil Samples for Inorganic Nitrogen Analyses1
Authors: Nelson D. W. , Bremner J. M.
Published: July 2010

Analysis of soils for inorganic forms of N is complicated by the fact that the amounts of these forms of N can change significantly during transport, pretreatment and storage of soil samples. Studies of the effects of several pretreatments and storage conditions on the inorganic N contents of 10 Iowa soils indicated that storage at —5 C in an airtight container is a satisfactory method of preserving field‐moist soil samples for inorganic N analyses. Storage at this temperature did not cause a significant change in the exchangeable ammonium N, nitrate N, or fixed ammonium N contents of the soils studied (the average change after storage at −5 C for 9 months was 0.1 ppm for exchangable ammonium N, 0.8 ppm for nitrate N, and 0.3 ppm for fixed ammonium N). Air‐drying at 22 C increased the inorganic N contents of most of the soils studied, with the average increase 4.2 ppm for exchangeable ammonium N, 1.7 ppm for nitrate N, and 4.4 ppm for fixed ammonium N. Oven‐drying at 55 C resulted in a slightly larger increase in exchangeable ammonium N (average, 5.1 ppm) than did air‐drying at 22 C, and drying at 22 C in ammonia‐free air caused a smaller increase in exchangeable ammonium N (average, 1.9 ppm) than drying at the same temperature in laboratory air. Storage of air‐dried soils in paper bags for 9 months led to marked increases in their inorganic N contents, with the average increase 10.2 ppm for exchangeable ammonium N and 5.5 ppm for fixed ammonium N. Only small increases in exchangeable ammonium N, nitrate N, and fixed ammonium N contents were observed when air‐dried soils were stored in stoppered bottles.
Competition Between Phosphate and the Plant for Fe from Fe2+ Ferrozine1
Authors: Brown J. C.
Published: July 2010

Much has been written about how phosphate accentuates Fe deficiency in plants; but little attention has been given to the genotype of rootstock as a controlling factor in Fe uptake. The important role of the plant was studied in these experiments.

Competition between phosphate, the plant, and ferrozine for Fe in nutrient solution was examined. Feinefficient and Fe efficient varieties of soybeans [Glycine max (L.) Merr.] (Lycopersicon esculentum Mill.) were used as test plants because they differ, respectively, in their ability to tolerate P and to reduce Fe3+ to Fe2+ at the root. Within 2 days after adding 16 ppm of P to the nutrient solution, only about 10% of the Fe2+ferrozine was colorimetrically detected in solution. The Fe was removed from Fe2+ferrozine, and it appeared in the solution as a suspension of iron‐phosphate. Phosphate was dominating the system for Fe. Four days later, the plants developed Fe deficiency (Fe stress). Fe‐efficient plants responded to Fe stress by releasing more H+ into solution and reducing more Fe3+ to Fe2+ than was reduced by Fe‐inefficient plants. As this occurred, Fe2+ferrozine reappeared in solution. The Fe‐efficient plants now dominated the system for Fe. On day 17 (final harvest), the green top leaves of Fe‐efficient HA soybeans contained 86 ppm of Fe, whereas the chlorotic top leaves of Fe‐inefficient PI soybeans contained only 36 ppm Fe. In the latter, phosphate still dominated the system for Fe because the reducing capacity (Fe3+ to Fe2+) of the Fe‐inefficient plants was not great enough to overcome the effects of phosphate.
Interaction of Temperature and Salinity on Sugar Beet Germination1
Authors: Francois L. E. , Goodin J. R.
Published: July 2010

Because high temperatures and soil salinity adversely affect sugarbeet (Beta vulgaris L.) germination in the southwestern United States, the interaction of temperature and salinity on germination was studied by a modification of the standard blotter technique. The interaction was highly significant. Salinity had little effect on germination at 10 C and 15 C but was increasingly inhibitory as temperature increased from 25 C to 40 C. Germination was maximum at 25 C, with low salinity, and almost completely inhibited at 45 C with all salinity levels. Of the four varieties studied, ‘US‐H2,’ ‘US‐H6,’ ‘US‐H8,’ and ‘HH‐5,’ germination of the US‐H2 variety was most sensitive to salinity over the 30‐C to 40‐C range.