bluuebunny/crossref_metadata_2025_split huggingface dataset:
Genotypic Response of Burley Tobacco (Nicotiana tabacum L.) to Air‐curing Detached Leaves1
Authors: Gupton C. L. 
Published: July 2010

AbstractBurley tobacco (Nicotiana tabacum L.) production still requires about 340 hours of labor per acre. Harvesting, barning, and preparing the leaf for market have about as intense labor requirements as 30 years ago. These operations must be mechanized to some degree to maintain production. The major objective of this study was to determine if there is a differential response of diverse burley genotypes when the leaf is cured detached from the stalk, with a view to producing cultivars whose mechanically‐harvested leaf possesses the normal characteristics of burley tobacco.Ten burley tobacco cultivars and breeding lines that differed from each other in plant type were grown in a split‐plot design with genotypes as whole plots and methods of curing as subplots. The methods of curing consisted of conventional air‐curing on the stalk and aircuring leaves that had been detached from the stalk and strung on sticks. Yield and grade index were determined for the cured leaf of each treatment. The leaf web was sampled and analyses for percent total nitrogen, percent α‐amino nitrogen, water‐soluble acids, pH, percent ash, percent K2O, percent nicotine, percent nornicotine, and content of citric and malic acids were made.Yield, pH, water soluble acids, percent total nitrogen, and percent α‐amino nitrogen were higher for detached than for stalk‐cured leaves. No significant differences existed between curing methods for percent K2O, percent nicotine, or percent nornicotine. Leaves cured detached were lower in percent ash and in grade index than those cured conventionally.Certain genotypes, such as Va 509, produced much more acceptable tobacco from the standpoint of both visual and chemical characteristics than others when the leaves were cured detached. Progress may be expected in breeding for cultivars that produce burley tobacco that is acceptable when it is cured detached from the stalk.
Errors Incurred by Use of Hydrogen Peroxide Digestion in Determination of Nitrate‐Nitrogen in Plant Material
Authors: Boggero J. D. , Stromberg L. K. 
Published: July 2010

AbstractDeterminations of the nitrate‐nitrogen (NO3‐N) content of leaf tissue samples of sesame (Sesamum indicum L.) by two analytical methods show that erroneous results may be obtained if digestion with hydrogen peroxide is employed during the procedure. This appears to be caused by the oxidation of nonnitrate nitrogen compounds to nitrates which results in higher nitrate levels than were present in the original samples.Nonnitrate nitrogen compounds of reagent grade, including two amino acids, were tested qualitatively for NO3‐N with negative results. These same compounds showed the presence of nitrate when tested both qualitatively and quantitatively after digestion with hydrogen peroxide.Sesame leaf samples demonstrated considerable absolute and relative errors in many cases when analyzed quantitative by two methods, one which employs hydrogen peroxide digestion and one which does not. The relative error is shown to be substantial, particularly at the lower levels of NO3‐N.
Comparative Response of Soybeans and Corn to Phosphorus and Potassium1
Authors: DeMooy C. J. , Young J. L. , Kaap J. D. 
Published: July 2010

AbstractMuch interest has developed concerning the comparative responses of soybeans [Glycine max (L.) Merr.] and corn (Zea mays L.) to fertilization. Grain yields of soybeans and corn grown side by side and in response to direct and residual P and K fertilizer applications were compared on an energy basis over 4 years of field experimentation. Corn was significantly more responsive than soybeans to direct and residual fertilizer P and to direct application of K. Limited nutritional requirements of soybeans were indicated by the small response from applied P and K fertilizers on land of low fertility, by the lack of response to more than a maintenance rate of P application, and by the fact that soybeans did not respond appreciably to a second cycle of P and K fertilization although the soil remained low in P and low to medium in K. The corn responded to the second increment of P and to a second cycle of P fertilization. Soybeans showed little difference between the effect of direct and residual fertilizer on yield. Corn responded to K in the year of application, but not to residual fertilizer. Differential response of corn from direct and residual P application was dependent on seasonal conditions. In the corn‐soybean cropping sequence on Webster silty clay loam where direct response from fertilizers occurred, P and K applications in alternate years were more effective for corn than for soybeans. The advantage of corn fertilization was relatively insensitive to soybean/corn price ratios.
Determinate Cotton Cultivars for More Efficient Cotton Production on Medium‐Textured Soils in the Lower Rio Grande Valley of Texas1
Authors: Namken L. N. , Heilman M. D. 
Published: July 2010

AbstractThe short‐season concept (early defoliation and early harvest) offers, perhaps, the greatest potential for increasing the efficiency of cotton (Gossypium hirsutum L.) production and for minimizing insect control requirements in the Lower Rio Grande Valley of Texas. Early defoliation also allows harvesting during the most optimum period in relation to expected rainfall.The fruiting, earliness, yield, and fiber quality of three determinate cultivars of early‐maturing cotton were compared with those of a standard nondeterminate cultivar to determine the potential of these cultivars for increasing cotton production efficiency in the Lower Rio Grande Valley. The determinate cultivars, ‘Paymaster 266,’ ‘Paymaster Dwarf,’ and ‘Acco 1764,’ produced their first blooms 3 to 7 days earlier and developed a very high rate of bloom production shortly after the first blooms, as compared with the standard cultivar, ‘TPSA 110.’ The determinate cultivars set fruit over a relatively short time, making early defoliation and harvest feasible with comparable yield and only a slight reduction in fiber quality.
Comparative Effects of Nitrogen and Sulfur Fertilization and Liming on Three Crops Grown on Four Soils1
Authors: Kemper D. W. , Sorensen R. C. 
Published: July 2010

AbstractTwo consecutive crops of corn (Zea mays L.), soybeans (Glycine max (L.) Merrill), and bromegrass (Bromus inermis) were grown in the greenhouse on four soils to 1) compare degree of response of these three crops to nitrogen and sulfur fertilizations as affected by overall soil characteristics; 2) evaluate the effect of soil characteristics on the relationship of dry matter production and plant N content; and 3) evaluate the N/S ratio and plant N content as indicators of adequacy of N for maximum dry matter production of these crops. The crops and soils were selected to give a wide range in crop and soil characteristics which would serve as a basis for concurrent comparisons.Dry matter production and plant N and S contents were determined. Regression procedures were used to develop response surfaces for the effect of N and S applications on these measured variables. Curves relating dry matter production with plant N content were examined for relationships among soils. Correlation was used to compare plant N content and N/S ratio as indicators of N supply for the plants.Response to nitrogen was common for corn and brormegrass but occurred to a smaller extent for soybeans. Although the magnitudes of N responses varied with the soil type, they were not closely related to soil organic matter or nitrate levels.Response to S was more evident during the second growing period than during the first period. Soybeans responded to S application only on the sandy Thurman soil. Interactions of N and S applications were observed primarily where large main effects of each of the fertilizers were observed. The CaCO3, had little effect on crop growth.The curves relating dry matter production to N content of the corn plants were essentially the same for all but one soil, whereas those for bromegrass were less similar. For soybeans, these two quantities were negatively related in several cases, indicating increasing plant growth with decreasing N content in the plant.The N content of the plant was more closely related to dry matter production than was the N/S ratio.
White Phosphorus‐Ammonia Reaction Product as a Phosphatic Fertilizer in Alkaline and Limed Acid Soils1
Authors: Hill Walter A. , Bohn Hinrich L. , Johnson Gordon V. 
Published: July 2010

AbstractWhite phosphorus dissolved in liquid ammonia yields an insoluble, black, phosphorus‐rich material. In alkaline and limed acid soils, this substance did not inhibit germination or seedling development of sorghum (Sorghum vulgare pers.) but supplied little or no phosphate to tomatoes (Lycopersicum esculentum, var. ‘manapal’). White phosphorus injected into the ammonia zone was available to the tomatoes as phosphates.
Wind Turbulence in a Soybean Field Sheltered by Four Types of Wind Barriers1
Authors: Radke J. K. , Hagstrom R. T. 
Published: July 2010

AbstractCrop yields and quality are frequently improved when the crop is sheltered by temporary, field wind barriers. To better understand the influence of temporary wind barriers on the microclimate, plant‐water relations, and crop yield, it is necessary to understand the effect of wind barriers on wind structure and turbulence.Several mathematical and statistical functions characterizing wind turbulence were determined for four types of wind barriers from hot‐film anemometer signals fed into a real‐time correlator with subsequent computer analysis. Wind barriers tested were double rows of corn (Zea mays L.), double rows of sunflowers (Helianthus annuus L.), a snowfence, and a solid board fence.The wind structure and turbulence parameters were always different behind the solid barrier compared to the porous barriers because the wind had to go up and over the top of the solid barrier. The porous barriers broke up the larger eddies into smaller eddies, decreased the wind velocity, and reduced the amount of energy at the lower frequencies. In general, the crop barriers gave results similar to those for snowfence for velocity but were different for energy, frequency, and scale considerations. The crop barrier leaves fluttered, causing greater energy dissipation and the generation of new distinctive frequencies. The corn and sunflowers gave similar results, although the sunflower barriers tended to be like a solid barrier because of their denser canopy.
Performance of Rice Varieties in a Highly Saline Sodic Soil as Influenced by Plant Population
Authors: Dargan K. S. , Abrol I. P. , Bhumbla D. R. 
Published: July 2010

AbstractIt is generally recognized that increased initial plant population or increased seeding rate in saline sodic soils would compensate for decreased germination, and seedling mortality. However, there is little or no experimental evidence of the gains obtained from such a practice. In present investigation the performance of seven rice (Oryza sativa L.) varieties at three plant populations in a highly saline sodic soil was studied in the field at the Central Soil Salinity Research Institute, Karnal, India. Varieties tested were the tall indica types ‘Jhona 349,’ ‘Jhona 351,’ ‘Basmati 217,’ and ‘Basmati 370’ and the semidwarf types ‘IR 8,’ ‘IR 8–68’ and ‘Jaya.’ Plant populations used were 2, 4, and 6 transplants/hill. Variety IR 8–68, a local selection from IR 8, with 6 transplants/hill gave the significantly highest grain yield at 57.33 quintals/ha. Variety IR 8 at 6 transplants/hill and Jhona 349 at 4 transplants/hill yielded next in order. Increase in plant population from 2 to 4 and 6 transplants/hill resulted in significantly higher grain yield in all varieties except Jhona 349 where there was a decrease at 6 transplants/hill. Increased yield resulted from increased survival of hills and greater number of panicle‐bearing tillers per hill.
Construction of Welded ‘Wet Loop’ Thermocouple Psychrometer Junctions1
Authors: Spomer L. Arthur 
Published: July 2010

AbstractThe construction and performance of a welded wire, wet loop (Richards') thermocouple psychrometer measuring junction are described. This junction is simpler to construct, not subject to the incomplete wetting error probable with previous designs, and more sensitive and stable than the silver ring junctions.
Overseeding Small Grain in Standing Soybeans vs Conventional Planting Methods1
Authors: Clapp J. G. 
Published: July 2010

AbstractRye (Secale cereale L.) and wheat (Triticum aestivum L.) were overseeded in a soybean (Glycine max (L.) Merrill) crop on both Coastal Plain and Piedmont soils. This method of seeding enables the small grain crop to be planted at an optimum time rather than being subjected to a possible delay in planting caused by a late soybean harvest and/or wet fields. Rye and wheat grain yields were 53 and 75% higher, respectively, for overseeding than for late plantings.
Effect of Root Pruning on Water Relations and Growth of Cotton1
Authors: Stansell J. R. , Klepper Betty , Browning V. Douglas , Taylor H. M. 
Published: July 2010

AbstractTo investigate changes in plant water use and growth rates brought about by the loss of a part of a root system, an experiment was conducted to determine quantitatively the effects of removing pan of a cotton (Gossypium hirsutum L.) root system. Approximately one‐fourth of the total root length was severed by forcing a sharp‐edged plate horizontally through the soil from front to rear of a rhizotron compartment. Root length was estimated from the number of roots appearing at the glass viewing surface of the compartment. Stem diameters were monitored continuously with linear variable differential transformers. Plant height was measured daily. Growth reductions after root pruning were greater when the root system was small and concentrated in the upper 25 cm of soil than when the root system was larger and confined to the upper 50 cm of soil. Consequently, effects of root damage by cultivation or by root pathogens may, in part, depend on the size and extent of the root system at the time of damage.
Lint Yield of Hill‐Dropped and Drill‐Planted Pima Cotton1
Authors: Kittock D. L. 
Published: July 2010

AbstractCotton (Gossypium sp.) growers in recent years have been changing from planting cotton by drill‐planting and thinning to planting to a stand. Much planting to a stand is done by hill‐dropping seed. This study was initiated to compare lint yield of ‘Pima S‐4’ cotton (G. borbadense L.) when drill‐planted and thinned and when hill‐dropped at 23‐cm spacing. There were three population levels, 1, 2 and 3 plants/hill, for hill‐dropped and comparable plant populations for drill‐planting and thinning. There were no significant differences in lint yield between hill‐dropping and drill‐planting in 3 years.
Differential Response of Oats to Manganese Stress1
Authors: Brown J. C. , Jones W. E. 
Published: July 2010

AbstractOat (Avena sativa L.) varieties differ in their susceptibility to Mn deficiency. A Mn‐efficient plant utilizes a limited supply of Mn, whereas a Mn‐inefficient plant, grown under identical conditions, develops Mn‐deficiency symptoms. The objective of this study was to characterize these differences.Four Mn‐inefficient oat varieties (‘Star,’ ‘Maelor,’ ‘Cayuse,’ and ‘Vicland’) and four Mn‐efficient oat varieties (‘S171,’ ‘Avon,’ ‘Park,’ and ‘Golden Rain’) were grown in nutrient solution containing increasing amounts of Mn. All of the Mn‐inefficient varieties except Star developed Mn‐deficiency symptoms when grown at 0.005 mg/liter Mn. None of the Mn‐efficient varieties developed the symptoms. Concentration of Ca was consistently greater in tops of the Mn‐efficient than in those of Mn‐inefficient oat varieties. Where the concentration of P was increased in the nutrient solution, Vicland contained more P and less Ca than Golden Rain. It is suggested that Ca may physically substitute for Mn at nonspecific sites in the plant, thus making more Mn available for specific chemical reactions that require it.
Nonionic Surfactant Effects on Growth and Porosity of Barley Roots1
Authors: Luxmoore R. J. , Valoras N. , Letey J. 
Published: July 2010

AbstractNonionic surfactant materials were applied in both solution and soil culture to assess the direct surfactant and the soil‐surfactant interaction effects on root dry weight and root porosity (gas space volume per unit root volume) of barley (Hordeum vuigare L.).Plants were grown for 28 days in solution culture with nonionic surfactant Soil Penetrant 3685 up to 100 ppm. Root dry weight was significantly reduced at 40 ppm and was further reduced to 32% of control plant root weight at 100 ppm. Root porosity, determined by the pycnometer method decreased from 13% (control) to 9% with 20 to 80 ppm surfactant. At 100 ppm, porosity was 4.5%. These results suggest that surfactant penetrated the root at concentrations above 20 ppm and caused flooding of intercellular gas spaces. At a high concentration (> 40 ppm) root growth decreased and the surfactant inhibited root tip meristematic processes. Soil Penetrant was more toxic to roots than Water In surfactant and this more toxic than Aqua Gro surfactant in a soil having little water repellency. Adsorption of surfactants by soil reduced the toxicity to roots. In a water repellent soil, root growth at 28 days was greatly enhanced with a 5,000 ppm addition of either Aqua Gro or Water In indicating more favorable soil‐plant water relations. In both soils root dry weight was reduced at high surfactant concentration, however, there were no significant effects on root porosity (mean value 5.7%) suggesting that root tip physiology was more affected by surfactants than internal root morphology.
Effect of Plant‐Available Stored Soil Moisture on Corn Yields. I. Constant Climatic Conditions1
Authors: Leeper R. A. , Runge E. C. A. , Walker W. M. 
Published: July 2010

AbstractAgronomists have long been interested in how variation in soils and climate are related to crop yields. An experiment was conducted to quantify the effect of weekly plant available stored soil moisture (PASSM) during 10 weeks of the growing season on corn (Zea mays L.) yield under constant and variable climatic conditions. The objective of this study was to determine how soils, varying in the amount of water supplied to corn, affect corn yield under constant climatic conditions. Plot yields from four Illinois locations (farms) for 3 years (1969–1971) were correlated with weekly PASSM, rooting depth, and available water‐holding capacity in the rooting zone. Experimental plots had high fertility and management levels. Approximately six sites to various depths to a root‐restricting glacial till or natric horizon, giving a wide range in independent variables, were established at each location. The PASSM values were calculated from weekly gravimetric moisture samples that were adjusted for rooting depth, bulk density, and 1/3 and 15 bar water retentions. The PASSM values were summed by a method similar to Fisher's polynomial technique as previously modified.The average R2 value of quadratic regression calculated for each year location was 58%. Above average PASSM was most beneficial either during tasseling or grain‐filling stages depending on the season. Quadratic regressions for each year‐location were calculated using rooting depth and available water‐holding capacity instead of weekly PASSM as the treatment variable, with average R2 values of 73 and 71%, respectively. The effect of each centimeter of rooting depth or available water‐holding capacity, as estimated from linear regression coefficients, varied considerably with the favorableness of the season. The lower precision of the weekly PASSM models, when compared with the rooting depth and available water‐holding capacity models was due to weekly sampling variation and possibly water movement above and below the soil surface. It was concluded that with adequate fertility and a high level of management, the potential of a soil to produce corn was largely determined by the soil's capacity to store and supply water.
Effects of Herbicides in a Crop‐Herbicide Rotation on Sulfur Oxidation in Tifton Soil1
Authors: Jones L. S. , Anderson O. E. , Dowler Clyde 
Published: July 2010

AbstractCrop production on light‐textured soils is often dependent on the microbial oxidation of sulfur from soil organic matter or S‐amended fertilizers. Because of the recognized influence of some herbicides on microbial activity, we investigated possible effects of herbicides on the oxidation of S. To study the possible relationship between S availability and herbicides, a field of Tifton Is was selected where herbicides had been applied for 3 years to soil on which corn, soybeans, cotton, and peanuts were grown continuously and in rotation. Recommended rates and methods of application were used in applying the chemicals. During the third year, soil samples were collected from the 0 to 15 cm layer of all plots. Samples were amended with elemental S, incubated at 32C, and sulfates were determined at 10‐day intervals. Oxidation of added S proceeded in all samples, and though the accumulation of sulfates was slowed during the first 10 days, never was it completely inhibited. Irrespective of treatment, the added S was completely oxidized to sulfate by the 40th day of incubation. Though the effect was minor, the combinations of herbicides applied to soybeans and peanuts tended to affect sulfofication more than those applied to corn and cotton.
Evaluation of Computational Methods for an Exponential Regression Model1
Authors: Carmer S. G. 
Published: July 2010

AbstractSeveral computational methods are available for the estimation of parameters A and K in the exponential regression model Y = NAKN relating yield of corn (Zea mays L.), Y, per unit area to plant density, N. From estimates of A and K two additional parameters may be estimated: Nopt, the agronomic optimum plant density, and Ymax, the maximum yield of corn which is obtained at the optimum plant density.Objectives in this study were to compare three methods of computing estimates of A, K, Nopt, and Ymax and to determine if the effects of computational methods vary with treatment design, random error magnitude, and random error structure. One computational method involves linearization of the model through logarithmic transformation, whereas the other methods retain the non‐linearity of the model and utilize iterative least squares procedures.Estimates of the four parameters were obtained from each of 100 simulated experiments for each of 270 combinations of nine treatment designs, two random error structures, five random error magnitudes, and three computational methods. Little of the variation in the 270 average values of each parameter was due to the effects of computational method, random error structure, or their interaction. Effects of treatment design, magnitude of random error, and then‐ interaction, however, accounted for 85 to 94% of the variation, depending on the parameter being estimated. Computational methods had only slight effects on coefficients of determination, average residual variances, and the range and bias of average parameter estimates.