bluuebunny/crossref_metadata_2025 huggingface dataset:
Relative Efficiency of Plot Sizes and Numbers of Replications as Indicated by Yields of Orchardgrass Seed in a Uniformity Test1
Authors: Rampton H. H. , Petersen Roger G.
Published: July 2010

Synopsis

Increasing replications or increasing plot size permitted detection of smaller differences in yield of orchardgrass seed. Accuracy of yield estimates changed most rapidly with change in replications. Hence, on a given area, most accurate yield estimates would result with plots of minimum size and increased replications. Plot cost:land cost relationships showed that as land cost increased, optimum plot size decreased. Optimum plot size for close‐drills was about half that for 3‐foot rows.
Influence of Soil Oxygen on Growth and Mineral Concentration of Barley1
Authors: Letey J. , Stolzy L. H. , Valoras N. , Szuszkiewicz T. E.
Published: July 2010

Synopsis

Techniques for varying soil oxygen in studies involving grasses are described. Vegetative growth of barley was found to be rather insensitive to low soil oxygen. Oxygen diffusion rates of approximately 15 × 10−8 gm. cm.−2 min.−1 is limiting for barley root growth whereas the optimum diffusion rate for shoot growth is less than 40 × 10−8. Low oxygen decreased the concentration of K and P in the shoot, but Na and Ca+Mg were not greatly influenced by the oxygen treatment.
Effect of Soil Temperature and Nitrogen Fertilization on the Growth of Soft Chess (Bromus mollis) at Two Elevations
Authors: Jones M. B. , McKell C. M. , Winans S. S.
Published: July 2010

Synopsis

Applied nitrogen increased the growth rate of the grass very little when the average soil temperature was below 45° F. Grass fertilized with nitrogen showed the greatest increase in growth compared with unfertilized grass when the average soil temperature was between 47° and 55°. When the temperature went above 55° the difference between unfertilized and fertilized grass decreased.
Leachable Nitrogen from Soils Incubated with Turfgrass Fertilizers1
Authors: Bredakis E. J. , Steckel J. E.
Published: July 2010

Synopsis

Leachable nitrogen was greatest in the first 3‐week period and varied as follows: (NH4)2S04 = Urea > castor pomace > Milorganite > Uramite = Nitroform. In the 3‐ to 12‐week period leachable nitrogen varied as: Uramite = Nitroform > castor pomace = Milorganite. Decreased soil acidity increased the leachable nitrogen from all materials in the first 3 weeks.
Estimates of Optimum Plot Size and Shape and Replicate Number for Forage Yield of Alfalfa‐Bromegrass Mixtures1
Authors: Torrie J. H. , Schmidt D. R. , Tenpas G. H.
Published: July 2010

Synopsis

Increasing plot length was more efficient than increasing plot width to reduce variation among plots for forage yield of alfalfa‐bromegrass mixtures. Estimates of optimum plot size and replicate number to detect differences among treatments were similar, using the coefficient of variability and Smith's b. Greater efficiency and less variation in the relative costs of plots of different sizes were observed for the lattice as compared with the randomized complete block designs.
Effect of Aluminum on Copper Sorption by Wheat1
Authors: Hiatt A. J. , Amos D. F. , Massey H. F.
Published: July 2010

Synopsis

The uptake of copper by excised wheat roots was inhibited by the presence of low concentrations of aluminum in the substrate. No evidence was obtained to indicate that copper and aluminum were competing for a common ion carrier involved in active accumulation. The inhibition tended to be overcome by higher levels of copper concentrations, suggesting that aluminum and copper were competing for common binding sites at or near the root surface.
Irrigation Water Management and Nitrogen Fertilization of Grain Sorghums1
Authors: Musick J. T. , Grimes D. W. , Herron G. M.
Published: July 2010

Synopsis

Grain yields were curvilinearly related to the number of irrigations, depletion of soil moisture, and increments of applied N. Evapotranspiration was related to number of irrigations and to available soil moisture. Plant growth response to applied N increased evapotranspiration slightly. Irrigation and applied N both increased the efficiency of water use. Maximum efficiency occurred at a yield level below maximum production.
Calculation of Orthogonal Coefficients When Treatments Are Unequally Replicated and or Unequally Spaced1
Authors: Carmer S. G. , Seif R. D.
Published: July 2010

Synopsis

A simple and easy method of calculation is presented and illustrated. It is based on the conditions necessary for orthogonality.
Effects of Mineral Nutrition on High Temperature Induced Growth Retardation of Kentucky Bluegrass1
Authors: Pellett Harold M. , Roberts Eliot C.
Published: July 2010

Synopsis

Turf grown on low N was more resistant to high temperatures than that on high N. Neither P nor K affected this resistance. High levels of N and P gave less‐resistant plants than high N and low P. The reverse was true with N and K.
Row Spacing, Plant Populations and Moisture Supply as Factors in Dryland Grain Sorghum Production1
Authors: Bond J. J. , Army T. J. , Lehman O. R.
Published: July 2010

Synopsis

Field experiments and long term weather data indicate that in the Southern Great Plains plant populations of about 18,000 plants per acre in 40‐inch rows will in most years result in the best grain yields. Forage production was higher with reduced row width and increased seeding rates. Results are explained on the basis of water availability and use during the growing season.
Principles of Nutrient Uptake From Fertilizer Bands. VI. Germination and Emergence of Corn as Affected by Ammonia and Ammonium Phosphate1
Authors: Allred S. E. , Ohlrogge A. J.
Published: July 2010

Synopsis

Free ammonia associated with diammonium phosphate fertilizer was toxic to germinating corn. Ammonia at partial vapor pressures as low as 0.125 mm. Hg was toxic to corn when it was exposed to this environment for 2 days during the initial stages of germination.
Pans in the Southern Great Plains Soils. I. Why Root‐Restricting Pans Occur1
Authors: Taylor H. M. , Mathers A. C. , Lotspeich F. B.
Published: July 2010

Synopsis

Seventeen root‐restricting pans of the Southern Great Plains were investigated. The concept that soil pans are either genetic in origin or that they develop as a result of man's manipulation of the soil can explain less than half of the cases. The theory is developed that the root‐restricting features of these 17 pans are caused by excessive soil strength that occurs largely as a result of soil drying.
Studies with Sudangrass. I. Effect of Growth Stage and Level of Nitrogen Fertilizer Upon Yield of Dry Matter; Estimated Digestibility of Energy, Dry Matter and Protein; Amino Acid Composition; and Prussic Acid Potential1
Authors: Jung G. A. , Lilly B. , Shih S. C. , Reid R. L.
Published: July 2010

Synopsis

Yields increased and digestibility decreased with advance in maturity. Nitrogen fertilization influenced yields markedly but had only a minor effect on digestibility of dry matter. Amino acid levels were altered by both cutting management and nitrogen fertilization. Prussic acid levels for all treatments were low and considered as safe for livestock.
An Evaluation of Nitrogen Fertilization in Legume‐Grass and All‐Grass Pasture1
Authors: Wedin W. F. , Donker J. D. , Marten G. C.
Published: July 2010

Synopsis

A simple legume‐grass mixture was more productive than a grass + N mixture in 1958 but less productive in 1959, following legume depletion due to winter‐killing. A low rate of nitrogen applied to depleted legume‐grass swards was economically superior to high rates on either legume‐depleted or all‐grass pastures, but especially the latter. Results over the 5‐year period suggest the desirability of seeding simple legume‐grass mixtures with limited nitrogen amendments after legume depletion rather than seeding of either complex or all‐grass mixtures.
The Growth and Yield of Corn. II. Daily Growth of Corn Kernels1
Authors: Duncan W. G. , Hatfield A. L. , Ragland J. L.
Published: July 2010

Synopsis

Under the conditions of this experiment the stalk was an important storage organ for sugar which, under some conditions, can be translocated to maintain dry weight growth of the kernels for extended periods in the absence of photosynthesis. It seems probable that sugar storage in the stalk provides most of the reservoir of readily mobile sucrose required to maintain relatively uniform kernel growth in spite of wide diurnal and day‐to‐day variation in photosynthesis.
An Exponential Model for Predicting Optimum Plant Density and Maximum Corn Yield1
Authors: Carmer S. G. , Jackobs J. A.
Published: July 2010

Synopsis

The relationship between yield of corn, Y, and plant density, N, per unit area may be depicted as Y = NAKN. Methods of estimating the parameters A and K and optimum density, Nopt, and maximum yield, Ymax, are presented. Data from a yield trial of 8 single cross hybrids at 4 densities are used to illustrate the usefulness of the model.
Effect of Temperature and Cutting on the Growth of Creeping Bentgrass (Agrostis palustris Huds.) Roots1
Authors: Beard James B. , Daniel William H.
Published: July 2010

Synopsis

The rate of growth of individual roots and total root production of creeping bentgrass was significantly reduced at 90° F. Cessation of growth of individual roots occurred more rapidly as temperature was increased from 60° to 90° F., but the rate of root growth on a per day basis was similar in the 60 to 80° F. range.
Effect of Planting Time and Photoperiod on Tephrosia vogelii
Authors: Irvine J. E. , Freyre R. H.
Published: July 2010

Twenty‐six consecutive plantings of Tephrosia vogelii were made at 2‐week intervals at Mayaguez, Puerto Rico, to determine the effect of planting time on growth rate, flowering, and rotenoid content. The replicated plantings showed that maximum growth occurred in the spring, irrespective of planting time. Flowering occurred as a photoperiodic response to a 13‐hour day or to an interrupted night. Leaf‐rotenoid content as measured by the red‐color test was lowest in spring and highest in fall in plants of the same age.
Soil Fertilization and Nitrate Accumulation in Vegetables1
Authors: Brown J. R. , Smith G. E.
Published: July 2010

Five different rates of nitrogen were applied to plots upon which were grown several different varieties of vegetables. Nitrogen fertilization caused significant increases in nitrate content in red radishes, kale, mustard, and turnip roots and tops. The maximum accumulation of nitrates appeared to vary with species, but differences in harvest dates between species precluded valid statistical tests of the differential accumulations. No significant differences in nitrate accumulation were found between varieties of the same species. Early maturing vegetables tended to accumulate more nitrate than late maturing varieties at a given rate of fertilization. Differences in nitrate content were observed at different sampling dates. The absence of phosphorus, potassium, or lime, or the presence of trace elements in the fertilizer treatment had no significant influence on nitrate accumulation.
Longevity and Dormancy in Seeds of Several Cool‐Season Grasses and Legumes Buried in Soil1
Authors: Rampton H. H. , Ching Te May
Published: July 2010

Nine kinds of crop seeds were buried in the field at 1‐, 2‐, 3‐, 5‐, and 7‐inch depths in Saran mesh bags to determine seed longevity and dormancy. Generally, persistence and viability were lowest at the 1‐inch depth and increased with depth, with differential longevity among species. Seeds of perennial ryegrass declined in viability most rapidly; orchardgrass and chewings fescue lost their viability after three winters; Highland bentgrass and Oregon annual ryegrass retained considerable viability; and red clover was highest in viability.
A Physiological Effect of Nitrogen on Phosphorus Absorption by Corn1
Authors: Leonce F. S. , Miller M. H.
Published: July 2010

A series of soil and solution experiments were conducted to study the mechanism responsible for the increased P absorption which occurs when N is added to a P fertilizer band.

The addition of (NH4)2SO4 or NH4Cl to a pellet P‐32 labelled, concentrated superphosphate placed 0.5 inch to the side of a corn root greatly increased the labelled P content of the plant tops. The addition of KNO3 reduced the P content of the tops when compared to concentrated superphosphate only. When the pellets consisted of phosphate only or phosphate plus KNO3, labelled P accumulated to high levels in the root as revealed by autoradiographs. No such accumulation occurred in the presence of NH4+ ions.

The addition of NH4NO3 to a nutrient solution increased the transfer of P through a 1‐inch segment of a corn root exposed to the solution, but did not influence the accumulation in the root.

It was concluded that the NH4+ ion has a specific influence on the transfer of P across the root symplast to the xylem.
Salt Tolerance of N. Co. Varieties of Sugar Cane. I. Sprouting, Growth, and Yield1
Authors: Bernstein Leon , Francois L. E. , Clark R. A.
Published: July 2010

The salt tolerance of N. Co. 293 and N. Co. 310 was determined in large greenhouse soil cultures with four levels of added NaCl and CaCl2 and in artificially salinized field plots. In the latter, sulfate salinity and high proportions of magnesium salts were also studied. ‘N. Co. 293’ was more salt‐tolerant than ‘N. Co. 310’ at moderate and high salinities, but both varieties had similar salt tolerance in the greenhouse at a low salinity. Yields decreased by 10% at 3 mmho/cm (ECe) and by 25% at about 5 mmho/cm. The ratoon crop in the field plots was only half as salt tolerant as the seed crop, and differences in salt tolerance between the varieties diminished during the second year. The greater sensitivity of the second year's growth is tentatively attributed to the combined effect of low winter temperature and salinity.
Poor Growth of Alfalfa (Medicago sativa) on Some Alberta Soils1
Authors: Webster G. R. , Khan S. U. , Moore A. W.
Published: July 2010

abstract

Alfalfa grows poorly on certain soils in central Alberta where it had previously grown well. All affected (“poor”) soils studied to date have light textured surface horizons. Plants are generally short, spindly, yellowish‐green, and poorly nodulated with patches of vigorous growth often scattered throughout the fields. Macro‐ and micro‐nutrients applied in the field have produced unsatisfactory responses.

A number of greenhouse experiments have been conducted using soils collected from areas of good and poor alfalfa growth and from an area that has never grown this crop. Steaming increased yields for two “poor” soils, and “Vaparn” increased yields and nodulation to a much greater extent than did fertilizer for one of these. Aqueous extracts from some “poor” soils, depressed growth and nodulation appreciably. Liming and nutrient solution increased yields for all soils, but failed to promote nodulation or produce healthy plants in soil sampled from areas of very poor growth. These treatments eliminate nutrient deficiency or toxicity as the primary causes for the poor growth. It would appear that these “poor” soils contain an agent toxic to alfalfa that is probably of biological origin. Barley was not affected by the toxic agent.
Apparent Photosynthesis in Field Soybean Communities1
Authors: Sakamoto Clarence M. , Shaw Robert H.
Published: July 2010

abstract

Limited data of net photosynthesis observations in a field chamber study indicated that a soybean community was light saturated at about 6,000 to 6,400 foot‐candles in the initial flowering stage and at 5,500 foot‐candles in the pod‐formation and the pod‐filling period. Thereafter, the saturation level dropped abruptly. Maximum net photosynthesis at light saturation showed a similar pattern.

Data are presented which showed that although leaf area increased from flowering to pod‐formation, net photosynthesis did not increase correspondingly.

Projection of the net photosynthesis‐light intensity curve indicates that the compensation point in the soybean community was about 1,000‐1,500 foot‐candles.
Chemical Fallow in Dryland Cropping Sequences1
Authors: Wiese A. F. , Burnett E. , Box J. E.
Published: July 2010

In continuous crops of dryland sorghum, propazine at 2.2 kg/ha eliminated one tillage and one cultivation operation during the crop year. At least one tillage operation was required to control volunteer sorghum before planting. In a wheat‐sorghum‐fallow cropping sequence, propazine at 2.2 kg/ha applied immediately after wheat harvest eliminated three tillage operations during the fallow period after wheat and one cultivation in the sorghum crop. The reduced tillage did not conserve extra wheat stubble for wind erosion control during the winter months. Diuron at 1.1 kg/ha applied in March to sorghum stubble eliminated cotton crop cultivation 2 of 4 years. Considerable sorghum residue was conserved for wind erosion control the winter after cotton harvest when no preplant tillage occurred.
Effect of Changes in Root Zone Temperature on the Subsequent Growth and Development of Young Corn Plants1
Authors: Beauchamp Eric G. , Lathwell D. J.
Published: July 2010

Corn plants were grown to defined stages of shoot development in sand culture at root zone temperatures of 15, 20, and 25C from emergence. Some plants were grown at constant root zone temperatures and others were transferred to the other two root zone temperatures at the 2‐leaf and 4‐leaf stages and then grown to the 4‐leaf and 6‐leaf stages, respectively.

The dry weights of the shoots and roots decreased with increasing root zone temperatures at similar leaf stages. Although relative growth rates and absolute growth rates were generally correlated, the latter were chosen on a rational basis to indicate the effects of root zone temperature changes on the rate of dry matter accumulation. The rate of morphological development of the plants increased substantially with increasing root zone temperatures. On the other hand, absolute growth rates of both the shoots and roots tended to be greatest at 20 and lowest at 25C. The optimum root zone temperature apparently decreased for shoot growth but increased for root growth during the 2‐leaf to 6‐leaf stage interval. The previous root zone temperature had a variable influence on subsequent growth for all three temperatures. This effect was difficult to explain but depended somewhat on the corn variety.
Comparison of Conventional and Automated Procedures for Nitrogen, Phosphorus, and Potassium Analysis of Plant Material Using a Single Digestion1
Authors: Thomas R. L. , Sheard R. W. , Moyer J. R.
Published: July 2010

Nitrogen content in 10 plant samples of widely varying concentrations of N, P, and K was measured by a H2SO4—H2O2 ashing procedure and the AutoAnalyzer system and found comparable to nitrogen content obtained by conventional Kjeldahl analysis. Phosphorus content measured by the AutoAnalyzer system on the same H2SO4‐H2O2 ashing was similar to that obtained by dry‐ashing combined with the molybdo‐vanadate procedure. Potassium analyses on the solutions from the two ashing procedures by atomic absorption spectroscopy were comparable. Details are presented for simultaneous N and P analysis by the AutoAnalyzer and for K analysis by atomic absorption on plant material performed on a single H2SO4‐H2O2 digest at a rate of 160 samples per week by one technician.
Nature of Ice‐Sheet Injury to Alfalfa1
Authors: Freyman S. , Brink V. C.
Published: July 2010

Ice sheets frequently result in widespread damage to herbaceous plants in temperate latitudes; the cause of injury is a matter of controversy. In a series of experiments with alfalfa in which artificial ice sheets were formed over essentially unfrozen soil, marked changes in the soil atmosphere were recorded. Under one ice sheet, for example, which lasted for 50 days, soil CO2 rose to 8.7% and alfalfa plants died. From observations such as this and from experiments in which the CO2, O2, and N2 in ice‐covered soils were artificially altered, it was concluded that CO2 accumulation is the prime factor in the death of herbaceous plants under ice sheets.

Intermittent thawing of artificial ice sheets reduced or eliminated injury. Stubble protruding through the ice sheet did not prevent injury.
Evapotranspiration by Snap Beans Grown in Sand Nutrient Culture1
Authors: Mielke L. N. , Peck N. H.
Published: July 2010

Evapotranspiration by snap bean plants was measured by continuously recording changes in volume of solution in a sand‐nutrient culture system. Evapotranspiration rate increased with increased plant growth up to complete leaf canopy coverage over the sand surface. Plants with a complete leaf canopy had a maximum evapotranspiration rate of 1.3 mm per hour at 1300 hour. Daily evapotranspiration had high correlations with vapor pressure deficit and pan evaporation.
Yield and Stand Survival of ‘Coastal’ Bermudagrass as Influenced by Management Practices1
Authors: Holt Ethan C. , Lancaster J. A.
Published: July 2010

A study was conducted over a 5‐year period to evaluate the effects of clipping practices and fertility levels on forage yields and stand survival of ‘Coastal’ bermudagrass, Cynodon dactylon (L) Pers. Yields were greater with a short stubble height (5 cm), infrequent harvest (35 to 40 cm of growth) and nitrogen fertilization. Yield and ground cover density increased with nitrogen fertilization and also in each succeeding year of the experiment. Root weight was not influenced by nitrogen fertilization and declined in each succeeding year of the study. Ground cover increase and root weight decline were slightly greater with close, frequent defoliation. Neither the density nor the root weight changes were related to yields. Differences in carbohydrate percent of both stems and rhizomes were detectable immediately following clipping, but no permanent or major sustained treatment effects were found. Height of cutting appears to be less important in Coastal bermudagrass production than either frequency of defoliation or level of fertilization, but Coastal bermudagrass will tolerate a wide range in both height and frequency of defoliation.
Relationship of Seedling Vigor to Respiration and Tetrazolium Chloride Reduction by Germinating Wheat Seeds1
Authors: Kittock D. L. , Law A. G.
Published: July 2010

The effects of age and size of seed on seedling vigor, rate of respiration, and 2,3,5‐triphenyl‐2H‐tetrazolium chloride (TTC) reduction by germinating seeds were studied in the laboratory. Wheat seed (Triticum aestivum ssp. compactum (Host) MacKey ‘Elmar’) was used. Stratification was necessary to eliminate the effect of dormancy in the youngest seed class. Significant positive correlations were found between rate of emergence and vigor (ability to emerge from deep seeding), emergence and rate of respiration, and between vigor and both tetrazolium reduction and rate of respiration for seed of different ages.

With different seed size classes, significant positive correlations were found between seed weight and tetrazolium reduction, and between shoot weight per plot and tetrazolium reduction.

In a preliminary test, varietal differences in seedling vigor, which were largely due to relative coleoptile elongation, were not correlated with TTC reduction. The possible place of TTC reduction as an empirical seedling vigor test and respiration of germinating seeds as a component of vigor are discussed.
Influence of Gas Mixtures on Cell Division and Root Elongation of Broad Bean, Vicia faba L.1
Authors: Williamson R. E.
Published: July 2010

Roots were grown in airtight chambers in an intermittent nutrient solution mist. Various gaseous mixtures were used to determine the effects of short‐term aeration deficiencies on cell division and root growth. Following treatments of 4 to 24 hours, the roots were aerated with air for 5 days. Root tip samples were prepared for microscopic examination at several times during and after treatment.

Oxygen levels of I to 10% without CO2 reduced the rate of cell division as much as 80% at the end of a 94‐ hour treatment; however, cell division resumed rapidly after treatment. Nitrogen reduced cell division in secondary roots within 15 minutes, stopped all division within 94 hours, and frequently killed primary root tips. After being returned to air, the rate of cell division in the old secondary root system was approximately 70% of normal within 48 hours, but few new roots developed. Mixtures of gases containing 1 to 10% O2 plus enough CO2 to equal 91% killed part of the secondary root system but rarely killed the primary root tip. These data show that either zero 02 or high CO2 for only 94 hours injures the root system of Vicia faba L. and that high CO2 is more injurious than zero 02.
Long‐Term Fertility Requirements of Coastal Bermudagrass, I. Potassium1
Authors: Woodhouse W. W.
Published: July 2010

A trial involving four levels of K on coastal bermudagrass was conducted over an ll‐year period on a Eustis sand. Applied K increased yields by about one‐third the first year with K deficiency becoming so acute on the K0 treatment in succeeding years as to virtually eliminate the stand on that treatment after the 7th year. Under low to moderate rates of applied K, the grass removed far more K than was applied. Roots penetrated to a depth of at least 244 cm and exchangeable K was affected to a depth of 122 cm. K content of the forage declined linearly from the beginning to the end of the growing season under low to intermediate levels of applied K. Optimum K content fluctuated widely both between and within growing seasons as did the degree of luxury consumption. Exchangeable K appears to be preferable to the strong‐acid method in identifying zones in this soil affected by the application of K. Neither method was effective in identifying supplies of native K. Findings indicate that long‐term trials with plants of this kind can be of value.
Effect of Planting Date on High‐Amylose Corn (Zea mays L.)1
Authors: Helm J. L. , Fergason V. L. , Zuber M. S.
Published: July 2010

Four high‐amylose single cross hybrids were planted near Columbia, Missouri, for the 4‐year period 1962 through 1965 on the following dates: April 20th, May 10th, June 1st, and June 20th. Amylose content of the endosperm and number of degree days during the growing season were inversely correlated with later plantings having higher amylose contents. However, later planted corn had a lower yield, test weight, whole kernel nitrogen content, kernel hardness, and number of days to tassel. Whole kernel ash content and ear height increased with later planting. It is doubtful if the increased amylose content of the endosperm will offset the reduced agronomic performance of later plantings.
Water Diffusivity of Germinating Soybean, Corn, and Cotton Seed1
Authors: Phillips Ronald E.
Published: July 2010

Theory and procedure are presented whereby the diffusivity of germinating seed can be calculated if certain conditions are fulfilled. These conditions are (1) the ratio of amount of water absorbed at a given time to amount of water absorbed at the time of germination must exceed a certain, critical value for the ratio of the time required for germination to the time under consideration, and (2) the shape of the seed is assumed to be a sphere but the seed can deviate considerably from the shape of a sphere, for example, football shaped, without introducing appreciable error.

The diffusivity of soybean seed germinating in aerated, distilled water was approximately four times larger than for corn seed and approximately 18 times larger than for cotton seed. The diffusivity of soybean and corn seed germinating in Zanesville silt loan soil at four moisture contents ranging from wilting percentage to field capacity was approximately equal at each soil moisture content. The diffusivity of each seed increased as soil moisture content increased. The diffusivity of cotton seed germinating in Zanesville silt loam soil could not be calculated because condition (1) above was not fulfilled.
Amazon Cacao (Theobroma cacao L.) Shade and Manurial Experiment (K2‐01) at the Cocoa Research Institute of Ghana. I. First Five Years1
Authors: Ahenkorah Yaw , Akrofi G. S.
Published: July 2010

The experimental layout, initial crop husbandry, preliminary girth measurements and yield results before and after the imposition of 2 years' shade and fertilizer treatments on the Amazon cacao Shade and Manurial Experiment (K2‐01) at Tafo are reported.

In assessing the uniformity of the 4‐year‐old cacao stand analyses of data on girth measurements gave C.V. of 10.26% and 12.86% for subplot and main plots, respectively. These are remarkably lower and highly satisfactory compared with the C.V. of 57.75% for the corresponding yield.

Statistical evaluation of variations between NPK fertilizer, block, cropping seasons, and shade effect is reported. The significant slope effect during the minor crop season was interpreted to be only a seasonal reflection of the probable variation in the available soil moisture. The shade effect of this experiment is compared with a similar and older experiment (Kl) at Tafo. The significant shade effect during the 1964/65 season in both cases varies with time of the year irrespective of the different shade trees.

Shade, K, and PK fertilizer effects are highly significant with the dtshaded cacao yielding almost twice as the plots under heavy shade whilst the fertilizer is about 10% greater. “No shade” with PK treatment has the uniformly highest yield followed by the “medium shade” with PK and the least being “heavy shade” with PK fertilizer. Shade effect is well marked during the main cropping season while that of K is pronounced without overhead shade.

There is a suggestion of rapid depletion of exchangeable K after 7 years of continuous cropping. The Amazon cacao on the WACRI series does not respond to the NPK fertilizer until it is over 5 years old.
Measuring the Color of Growing Turf with a Reflectance Spectrophotometer1
Authors: Birth Gerald S. , McVey George R.
Published: July 2010

A single−beam spectrophotometer was used to measure the spectral reflectance properties of growing turf. From the data a two−wavelength reflectance ratio R745/R675 was developed for an objective index of turf color. This ratio changed from 3.0 for light green turf color to 6.5 for dark green turf color. (visual rating of 4 to 10, respectively). A two−filter instrument (Ratiospect) was used to measure this index on eight samples of turf of three species. A correlation of 0.984 was obtained between the Ratiospect readings and a visual score of turf color.
Effect of Several Fertilizer Treatments on the Production of American Beachgrass Culms1
Authors: Augustine Marshall T. , Sharp W. Curtis
Published: July 2010

Coastal dune stabilization is greatly influenced by the type of vegetative cover. The most effective plant species for initial dune stabilization along the Atlantic coast is American beachgrass (Ammophila breviligulata Fern.) being very responsive to fertilization as measured by culm numbers produced.

Each of 17 different fertilizer treatments significantly increased culm production. Potassium increased production in the 1st year only. Annual fertilization with soluble nitrogen fertilizer alone was effective. Magnesium ammonium phosphate as Mag Amp, applied at planting only, rapidly increased culm numbers for 3 years but decreased thereafter, approaching the effectiveness of annual applications of mixed 10‐10‐10 mineral fertilizer.
Emergence Time, Seed Quality, and Planting Depth Effects on Yield and Survival of Cotton (Gossypium hirsutum L.)
Authors: Wanjura D. F. , Hudspeth E. B. , Bilbro J. D.
Published: July 2010

Time of emergence is a good indication of a cotton plant's vigor and potential yielding ability. Emergence time of the cotton plant integrates the effects of seed quality and planting depth. In this study, plant survival and yield were most highly correlated with emergence time and to a lesser degree with germination percentage and planting depth.
Coding of the Independent Variable in Yield Function Calculations1
Authors: Escobar Giron Jorge A. , Cady F. B.
Published: July 2010

Coding or transforming the independent variable(s) in regression situations affects estimation and hypothesis testing. Methods are developed for understanding these coding effects and a table presented with the factors required to calculate easily the estimated coefficients and subsequent t‐statistics in one system of coding from another. The systems of coding include four commonly used codings of the original values. A worked example of a quadratic polynomial model in two variables is then given and the results interpreted with the objective of decreasing the potential confusion that may arise from a coding situation, e.g., when the independent variables have been coded for convenience in calculation but the final yield function is desired in units of the original variables.
Relationships Between N Response, Plant Population, and Row Width on Growth and Yield of Corn1
Authors: Nunez Roberto , Kamprath Eugene
Published: July 2010

The leaf area index increased linearly as the plant population of corn (Zea mays L.) was increased from 34,500 to 69,000 plants per hectare. The leaf area per plant, however, decreased as the plant population increased. Nitrogen rates of 112 to 280 kg per hectare and row width had no effect on leaf area per plant nor the leaf area index.

The yield of grain per plant was dependent upon the leaf area per plant. The efficiency of a given leaf area to produce grain was higher as nitrogen rates increased.

The yield of grain per hectare of the long season hybrid was not influenced by row width except under drought conditions where 53‐cm wide rows gave higher yields than 106‐cm wide rows. Highest grain yields were obtained at 280 kg of N per hectare and 51,750 plants per hectare. Maximum yields were obtained with a leaf area index of 3.5 and remained constant up to an index of 4.5 with adequate nitrogen.
Effects of Nitrogen‐Potassium Levels on the Growth and Chemical Composition of Kentucky Bluegrass1
Authors: Monroe C. A. , Coorts G. D. , Skogley C. R.
Published: July 2010

The performance of an apomictic strain of Kentucky bluegrass under eight fertility levels was studied during 1966 and 1967 under greenhouse conditions. Fertilizers were applied as nutrient solutions. Treatments included two nitrogen (65 and 130 ppm) and four potassium (0, 100, 200, and 400 ppm) levels in all factorial combinations. Clipping weights, weights of underground plant parts (roots and rhizomes) and tops, vigor scores, tiller counts, blade widths, and rhizome lengths were taken as measures of growth. Amounts of N, P, K, and C in leaf tissue were determined by chemical analysis.

All growth measurements, except rhizome lengths under 130 ppm N, were increased by potassium when compared to the 0‐ppm K level. However, levels of K above 100 ppm were often detrimental under 65 ppm N and sometimes had little effect with 130 ppm N.

N content of leaf tissue was increased by 130 ppm N while levels of K exceeding 100 ppm appeared to cause a slight, although significant decrease under both N rates. N and K had no significant effect on P content of leaf tissue. Added K increased the amount of K in leaf tissue up to the 200 ppm level. High nitrogen increased the K content significantly, but the increase was less than 0.2%.

The balance between N and K appeared to effect growth responses. With 65 ppm N, 100 ppm K had the greatest effect on increasing growth measurements. With 130 ppm N, the balance requirement was less critical but the 200 ppm level gave the greatest growth measurement increases. The 400 ppm K level generally resulted in reduced growth regardless of N levels.
Water Use by Cotton From Low and Moderately Saline Static Water Tables1
Authors: Namken L. N. , Wiegand C. L. , Brown R. G.
Published: July 2010

A 4‐year lysimeter study was conducted to determine the contribution of low to moderately saline, shallow static water tables to the total water use and yield of cotton grown on deep, permeable soils. Water tables controlled at 91‐, 183‐, and 274‐cm depths contributed 54.4, 26.4, and 17.3% of the total water use under the high moisture treatment and 60.6, 48.9, and 39.2% under the low moisture treatment. Total water use consisted of soil profile depletion, rainfall, irrigations, and additions of water to maintain the water tables. Water uptake from the 274‐cm water table was strongly related to the salinity level (electrical conductivity of saturated soil extract, ECe) of the capillary (183‐ to 274‐cm) zone. Lint cotton yields were related to the total amount of water obtained from the table as well as to the salinity level of the capillary zone. Moderate salinity (ECe of 10 to 14 mmhos/cm) of the capillary zone reduced monthly and seasonal water use from the water tables as compared with low salinity (ECe of 2 to 3 mmhos/cm) conditions. The high moisture treatment delayed significant use of water from 183‐ and 274‐cm water tables until late in the season, when irrigations were discontinued and the upper soil profile dried.
Performance of Three Grass Species Grown Alone and with Alfalfa under Intensive Pasture Management: Animal and Plant Response1
Authors: Hamilton R. I. , Scholl J. M. , Pope A. L.
Published: July 2010

Animal and plant responses of three grass species: smooth bromegrass (Bromus inermis Leyss.), timothy (Phleum pratense L.), and orchardgrass (Dactylis glomerata L.), grown alone and fertilized with nitrogen (112, 146 and 168 kg N/ha in 1962, 1963, and 1964, respectively) and each grass in two‐component mixtures with ‘Vernal’ alfalfa, (Medicago sativa L.), were measured at Arlington, Wis.

Animal response, measured by average daily lamb gains and total weight gains per hectare did not differ between grass species, although alfalfa‐dominant swards showed a trend towards higher total weight gains in comparison to the grass species grown alone with nitrogen fertilizer. Although no differences occurred between varieties within species, species did differ in total forage dry weight yields, aggressiveness in mixtures, seasonal distribution of dry matter production, winter hardiness and persistence.
Reflectance and Internal Structure of Cotton Leaves, Gossypium hirsutum L.1
Authors: Gausman H. W. , Allen W. A. , Myers V. I. , Cardenas R.
Published: July 2010

Cotton (Gossypium hirsutum L.) plants were grown hydroponically in a controlled environment. Sodium chloride was used to induce three osmotic stresses: low (0 atm), medium (6 atm), and high (12 atm). Leaves of approximately the same age were harvested 49 days after planting from five replications of each treatment, and their reflectance and transmittance spectra were obtained for the wavelength interval 500‐ to 2,500µ Osmotic stresses of 6 and 12 atm reduced reflectance and increased transmittance of near‐infrared light (750 ‐ 1,350 mµ) as compared with leaves from plants grown with low osmotic stress. Tissue sections from the same leaves were processed to provide transverse sections for histological examination; leaves from plants grown with 6 and 12 atm of osmotic stress exhibited a more compact cell arrangement than nonosmotically stressed leaves.
Factors Affecting Plant Growth in High‐Zinc Medium: I. Influence of Iron on Growth of Flax at Various Zinc Levels1
Authors: Lee C. R. , Craddock G. R. , Hammar H. E.
Published: July 2010

Growth chamber experiments, employing a two‐zone root technique and nutrient solutions, were conducted to study the influence of iron on the growth of Linum usitatissimum L., fiber flax, at various levels of zinc sulfate. Zinc and iron variables were added to one root zone, while all other essential nutrients were added to a second root zone. Plant growth in nutrient solutions containing as much as 1.00 ppm of Zn was increased by the addition of 5.0 ppm of iron as FeCl3. Competition for root absorption sites existed between Zn+2 and Fe+3. Zinc appeared to interfere with iron uptake, whereas iron did not interfere with zinc uptake. FeEDDHA (sodium ferric ethylenediamine di‐[o‐hydroxyphenylacetate]) and Rayplex Fe (iron complexed with modified polyflavonoid copolymers) also increased plant growth in solutions containing 0.50 ppm zinc.
Relative Occurrence of Toxic Concentrations of Cyanide and Nitrate in Varieties of Sudangrass and Sorghum‐Sudangrass Hybrids1
Authors: Gillingham J. T. , Shirer M. M. , Starnes J. J. , Page N. R. , McClain E. F.
Published: July 2010

A field experiment was conducted to determine the concentrations of CN and NO3‐N that could occur in successive aftermaths of recommended varieties of Sudangrass (Sorghum sudanense P. Stapf) and sorghum‐sudangrass hybrids (Sorghum bicolor L. Moench × Sorghum sudanense P. Stapf) when fertilized with frequently used rates of N.

Nitrate concentration was affected by N rate, and CN concentration was affected by N rate, variety, and especially height of the forage (P=.05). The overall varietal means for CN concentration were: ‘Trudan II’‐189, ‘Su Chow 34’‐326, ‘Sweet Sioux’‐378, ‘Grazer A’‐396, and ‘Tift’‐402 ppm CN. The probability of CN poisoning was found to exceed that for NO3 poisoning significantly.

Attention is called to the special case where toxic concentrations of CN and NO3 coexist in these forages; a poisoning would result in which methemoglobin arising from the NO3 poisoning would be a “built‐in” treatment for the initial and rapid detoxification of CN. Consequently, in this situation NaNO2 injection, to induce a limited methemoglobinemia, should be omitted.

We suggest that diagnosis and treatment of symptoms associated with “nitrate poisoning” in animals eating these heavliy fertilized aftermaths or green chop should involve more than clinical judgement. Cyanide poisoning should be confirmed or excluded before treating sick animals for NO3 poisoning.
Annual Legume‐Grass Mixtures for Forage and Seed1
Authors: Robinson R. G.
Published: July 2010

Mixtures of soybeans (Glycine max (L.) Merr.) and annual grasses were compared with soybeans for forage production. Soybeans‐foxtail millet (Setaria italica (L.) Beauv.) was the best mixture and exceeded soybeans in forage yield, dry matter percentage, weed control, and lodging resistance. The mixture equalled soybeans in protein yield but was lower in protein percentage.

Oat (Avena sativa L.)‐legume mixtures, legume mixtures, and legume‐Brossica mixtures were compared with oats alone for forage and seed production. Oat‐legume mixtures were superior to pure oats in protein yields and concentrations but did not produce greater forage or seed yields. Oat‐horsebean (Vicia faba L. equina Pers.) mixture is an alternative to oats‐peas (Pisum sativum L.) for fertile soils where oats‐peas lodge badly.

Alternate rows of soybeans and millet produced forage of higher protein percentage but lower forage yield than did drilling soybeans and then broadcasting or drilling millet. For oat‐horsebean mixture, alternate rows were less satisfactory than mixed drilling.
Variable Selectivity for Sr by Corn Hybrids Which Accumulate Different Concentrations of Sr, Ca, Mg, and K1
Authors: Bradford R. R. , Baker Dale E.
Published: July 2010

Four single‐cross corn hybrids (Zea mays L.) which differ with respect to their accumulations of Ca, Sr, Mg, and K were grown under greenhouse conditions in soil treated with 0, 100, 200, and 400 ppm of Sr as SrNO3. The investigation was conducted to determine if these hybrids would exhibit variable selectivity for Sr compared with Ca and Mg.

All hybrids responded substantially to Sr additions to the soil. The concentrations of Sr in hybrids I and IV increased more with increasing rates of Sr than was observed for the other two hybrids. Relative to concentrations of Ca plus Mg in the plants, hybrid IV accumulated more Sr than did hybrid III with the other two hybrids being intermediate. Results for selectivity ratios indicated that Sr was removed as readily by hybrid IV as were Ca and Mg, while other hybrids were selective for Ca and Mg in preference to Sr. It was concluded that although variable selectivity was evident among the hybrids, the concentrations of Sr accumulated by the hybrids were predominantly a function of the availability of Sr in the soil and the Sr and Ca accumulation characteristics of the hybrids. It is not likely that hybrids can be developed which accumulate high concentrations of Ca and low concentrations of Sr.
Effect of Phosphorus and Potassium on Alfalfa Root Anatomy1
Authors: Schnappinger M. G. , Bandel V. A. , Kresge C. B.
Published: July 2010

The effects of P and K on alfalfa (Medicago saliva L.) root anatomy were determined. A sand culture method was used to grow the plants. Phosphorus (P) levels in the nutrient solutions were 0, 3.4, 6.9, 13.8, 27.7, and 55.4 ppm at the beginning of the experiment. Potassium (K) was supplied at the rates of 0, 4.3, 8.6, 17.3, 34.6, 51.9, 69.3, and 173.2 ppm. No effort was made to maintain the nutrient solutions at their initial levels.

Plants were harvested three times at approximately 28‐day intervals when the plants were in the full‐bloom stage. The roots were preserved in a 70% Formalin‐acetoalcohol fixative. Permanent microscope slides were prepared from which various characteristics of alfalfa root anatomy could be studied.

Root diameter was Increased by the addition of either P or K to the nutrient solution. Xylem vessel diameter was decreased by the removal of either P or K. But, removal of P from the nutrient solution had a greater effect on xylem vessel diameter than did K. Xylem vessel differentiation as well as the percent of the root area occupied by xylem vessels was increased more by P than by K.
Monitoring Cotton Plant Stem Radius as an Indication of Water Stress1
Authors: Namken L. N. , Bartholic J. F. , Runkles J. R.
Published: July 2010

Cotton plant water stress was monitored continuously during a drying cycle by measuring microchanges in plant stem radius with a linear variable displacement transducer (LVDT). Plant stem contraction was directly related to the degree of leaf water stress, and plant stem radius was very responsive to changes in the energy load at the evaporating surface. The LVDT provided a stable, trouble‐free method for monitoring relative plant water stress under field conditions without destroying plant tissue.
Effect of Windbreaks and Soil Water Potential on Stomatal Diffusion Resistance and Photosynthetic Rate of Sugar Beets (Beta vulgaris)1
Authors: Brown K. W. , Rosenberg Norman J.
Published: July 2010

The stomatal resistance (rs) to diffusion of water vapor and CO2 through leaves of sugar beets grown in well irrigated open plots and plots sheltered by windbreaks was calculated from measurements of stomatal density and aperture.

Mean daily stomatal resistance in both sheltered and exposed situations increased markedly as the soil water potential decreased from −035 to −0.52 bars. As potential decreased, increases in the stomatal resistance occurred earlier in the day. Superimposed upon this increase in resistance were cyclical changes which were attributed to the readjustment of stomatal apertures necessary for the maintenance of a balance between water uptake and loss. The results suggest that, even under well‐irrigated conditions, climatic stresses characteristic of the Plains environment may induce partial slomatal closure during afternoon hours on many days.

The mean stomatal resistances were found to be independent of CO2 concentration, air temperature, water vapor pressure, and wind speed, except in an extreme case where the passage of a front caused high winds and the influx of dry air. In this case, the stomatal resistance increased sharply.

Mid‐day values of stomatal resistance averaged 1.4 sec cm−1. The mean difference in stomatal resistance between the open and sheltered plots can explain a 6% decrease in the resistance to CO2 flux and therefore a 6% increase in photosynthetic rate in shelter. The extreme observed difference in r. can explain a 26% increase in photosynthetic rate in shelter.

These results occurred under conditions of ample irrigation. The data suggest that photosynthetic rate should be even more strongly favored where plants grown on dryland are sheltered from wind.