bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nitrogen, Chloride, and Water Balance with Irrigated Russet Burbank Potatoes in a Sandy Soil1
Authors: Saffigna P. G. , Keeney D. R. , Tanner C. B. 
Published: July 2010

AbstractLarge applications of sprinkler irrigation and N fertilizer have been implicated in causing nitrate contamination of ground water in central Wisconsin.Field and lysimeter experiments were established in 1972 and 1973 on the Plainfield loamy sand to determine the effect of reducing the amount of sprinkler‐irrigation and fertilizer N on potato (Solanum tuberosum L., var. ‘Russet Burbank’) tuber yields and on the field water and N balance. Two main treatments were used. The conventional (CON) treatment received irrigation water and N fertilizer according to current recommendations. The improved (IMP) treatment received less irrigation water than the CON treatment in both years. In both years fertilizer N was applied more frequently to the IMP treatment and in 1973 the total amount applied was less in the IMP treatment than in the CON treatment. Chloride (as KCl) accompanied N on a one‐to‐one weight basis to provide an independent ion for tracing. Additional subtreatments included planting potatoes without hilling in a furrow, additional application of N late in the season, and cropping a high N fertility area.The overall average fresh weight tuber yield was 515 q/ha. Total yields were the same in both CON and IMP treatments for both years. However, grade A tuber yields were greater on the IMP treatment than the CON treatment in 1973 when irrigation was applied every 3 rather than every 5 days, and fertilizer N was applied in 11 rather than three doses. The greater grade A tuber yields occurred despite a decrease in fertilizer N from 260 to 170 kg N/ha and a decrease in irrigation water applied from 45 to 27 cm. Evapotranspiration and N uptake by tubers were not appreciably affected by irrigation and N management.In 1973 most of the N applied at planting was leached except where S‐coated urea was used to provide a source of slow‐release fertilizer N. Application of fertilizer N and Cl with the irrigation water resulted in substantial variability in inputs over the plot area due to variation in the water distribution. The average coefficient of variation for inputs of fertilizer and water was 19% and the average uniformity coefficient (Cu) was 85%.A satisfactory mass balance of water, N and Cl for potatoes grown in the dosimeters was obtained. Drainage accounted for considerable amounts of the water, N, and Cl outputs with nearly all of the remainder going to and plant uptake. The carefully managed IMP treatment decreased NO3‐N leaching from 200 to 120 kg N/ha and lowered the overall average NO3‐N concentration of the leach ate from 23 to 16 mg N03‐N/liter. However, the additional costs required to effect a small savings in N fertilizer is probably not justified.
Crownvetch‐Grass Mixtures under Frequent Cutting: Yields and Nitrogen Equivalent Values of Crownvetch Cultivars1
Authors: Hart Richard H. , Thompson A. J. , Hungerford W. E. 
Published: July 2010

AbstractCrownvetch (Coronilla varia L.)‐grass mixtures are recommended for pastures, but data were needed on forage yields under frequent severe defoliation, and on yields of crownvetch‐grass mixtures vs. grass fertilized with N. ‘Penngift’, ‘Chemung’, and ‘Emerald’ crownvetch were seeded with ‘Ky‐31’ tall fescue (Festuca arundinacea Schreb.), ‘Potomac’ orchardgrass (Dactylis glomerata L.) and Kentucky bluegrass (Poa pratensis L.) in 1965 in a field trial on a fine‐loamy, mixed mesic Fluvaquentic Dystrochrept. Mixtures were clipped every week, 2 weeks, or 4 weeks, leaving a 5‐ or 10‐cm stubble, in 1968 and 1969. In 1970, we removed crownvetch from some plots with herbicide. In 1970 and 1971, we applied N at 112 or 224 kg/ha to the resulting pure grass plots, and cut all grasses and mixtures every 2 weeks. Only fescue and fescue‐crownvetch mixtures were studied in 1972 and 1973. Fifty‐six, 112, 168, and 224 kg N/ha were applied, and all entries were cut every 2 weeks.In 1968 and 1969, yields of all mixtures increased as the interval between cuttings increased. Yields of all mixtures in 1968 and 1969, and of grass plus N in 1970 and 1971, were higher when cut back to 5‐cm rather than 10‐cm stubble height. Penngift‐grass mixtures outyielded Chemung‐ and Emerald‐grass mixtures at both stubble heights from 1968 to 1971, and at the 5‐cm stubble height in 1972. Over 4 or 6 years, Penngift‐grass mixtures produced about 30% more forage than Chemung‐ or Emerald‐grass mixtures. Bluegrass‐crownvetch often outyielded orchardgrass‐ or fescue‐crownvetch in 1968 and 1969, but total yields over 4 years of bluegrass‐, orchardgrass‐, and fescue‐crownvetch mixtures were almost the same. Fescue plus Penngift produced as much forage as fescue plus 155 and 62 kg N/ha in 1970 and 1973, respectively (mean of 5‐ and 10‐cm stubble). Corresponding N equivalent values were 69 and 39 kg/ha for Chemung and 88 and 25 kg/ha for Emerald.
Effects of Paraquat on Yield and Quality of Coastal Bermudagrass1
Authors: Monson Warren G. 
Published: July 2010

AbstractParaquat (1, l'‐dimethyl‐4‐4‐bypyridinium ion) has been utilized as a pasture renovation tool and to provide “cured” standing forage for later utilization. This study was undertaken to determine the amount of standing ‘Coastal’ bermudagrass (Cynodon dactylon L.) forage that can be successfully desiccated with paraquat. Subsequent effects on yield and quality of the grass were assessed.Accumulated Coastal bermudagrass up to 4 metric tons/ha can be effectively desiccated with paraquat. Quality of Coastal hay desiccated with paraquat decreased by more than 20%, within 1 week after treatment, indicating that this is not a practical means of providing cured forage in situ in the humid southeastern United States. Paraquat plus burning can be used to remove accumulated forage and redistribute some of the dry matter production or provide succulent regrowth in late summer if moisture is adequate. Paraquat plus burning to remove forage reduced yields significantly P < 0.05 when compared to mowed plots.
Sequential DCPA Treatments for Weed Control in Turfgrasses1
Authors: Johnson B. J. 
Published: July 2010

AbstractIn the southeastern USA, herbicides have not generally given consistent preemergence control of large crabgrass [Digitaria sanguinalis (L.) Scop.] and annual bluegrass (Poa annua L.). DCPA (dimethyl tetrachloroterephthalate) was applied as single and repeated treatments over a 3‐year period for large crabgrass control at Griffin and Blairsville, Georgia, and for annual bluegrass control at Griffin. The soil types were Cecil sandy loam (Typic Hapludult) or sandy clay loam at Griffin and Hatboro loam (Typic Fluvaquents) or sandy loam at Blairsville.None of the DCPA treatments controlled large crabgrass or annual bluegrass consistently at the, rates included in these studies. Treating plots with DCPA at 11.2 kg/ha in both March and June gave the greatest control in 2 of 3 years at each location. A significant multiple correlation between temperature prior to treatment and weed control ratings indicated that poor control of large crabgrass was related to germination of crabgrass prior to treatment. High temperatures that induced germination of crabgrass during 2 weeks prior to time of treatment resulted in less control than in years with lower temperatures. This emphasizes the need for early application of DCPA in Georgia.
Effect on Plant Growth of Constricting Forces Applied to the Upper Part of Roots1
Authors: White Everett M. 
Published: July 2010

AbstractContraction forces developed by soils as they dry may compress roots and reduce growth. In order to evaluate this effect on growth, plants were placed with their upper roots between two rigidly fixed adjacent plastic tubes that could be inflated against the roots with 0 to 15 bars air pressure. Root and top growth of corn (Zea mays L.), oats (Avena sativa L.), and western wheatgrass (Agropyron smithii Rydb.) decreased gradually as a constricting force on the upper part of the roots was increased from about 4 to 15 bars. At pressures lower than about 4 bars, growth was larger than growth of the plants in loose sand, which applies little if any constricting force on roots. When wet puddled soil was dried around the upper roots of corn or oat seedlings, growth was decreased in some experiments and increased in others possibly because the pressure was larger or smaller, respectively, than 4 bars. The effect that drying of poor soil structure has on compressing roots and reducing plant growth needs to be investigated.
Effects of Natrustoll (Solonetz) Soil Horizons and Nitrogen on Growth of Tall Wheatgrass1
Authors: McGinnies William J. , Ludwig Jim R. 
Published: July 2010

AbstractVast hectarages of potentially valuable pasture land in Colorado and Wyoming are dominated by saltgrass (Distichlis stricta (Torr.) Rydb.), an undesirable pasture component. Saltgrass meadows could possibly be revegetated with a more valuable forage species such as tall wheatgrass (Agropyron elongatum (Host) (Beauv.). A greenhouse study was conducted to evaluate the effects of the A, B, and C horizons of a solonetz soil on herbage yield of tall wheatgrass; the effect of N application was also investigated. Yields of plants grown in soils from the A horizon were highest, those from the B horizon where somewhat lower, and those from the C horizon were very low. Mixtures of A and B horizons usually produced higher yields than the A or B alone. Plants grown in any soil mixture which included the C horizon showed reduced yields. The deleterious effect of the C horizon was attributed to its high Na‐salt content. Nitrogen, applied at rates equivalent to 56 to 448 kg N/ha, significantly increased herbage yield. Compared to no N application, the highest rate resulted in a three‐fold increase in yield. The highest N efficiences in terms of total biomass produced per unit of N applied were obtained from rates of 112 and 224 kg N/ha which produced 39 and 37 kg of additional biomass per kg of N applied, respectively.
Soaking Procedures and Hydroseeder Damage to Common Bermudagrass Seeds1
Authors: Kay Burgess L. , Evans Raymond A. , Young James A. 
Published: July 2010

AbstractHydroseeding is increasingly important as a technique for vegetating roadside, industrial, and residential areas. Presoaking of seeds in solutions of growth regulators has proven valuable as a germination accelerator in the laboratory, but has not been previously field tested. The objectives of these studies were: 1) to develop production procedures for presoaking seeds of hulled common bermudagrass [Cynodon dactylon (L.) Pers.] in solutions of growth regulators, 2) to determine whether presoaked seeds were damaged in a commercial hydroseeder, and 3) to demonstrate the effectiveness of presoaking under field conditions. We undertook these studies because hydroseeding is extensively used in the USA, and presoaking seeds has been shown to be valuable to this industry. To determine optimum procedures, seeds were soaked for 24 through 96 hours in an aqueous solution containing 1.0 mmole/liter KNO2, 0.035 mmole/liter GA3 and 0.01 mmole/liter kinetin at seed‐to‐solution ratios by weight of 1:1, 1:2, 1:5, 1:10, 1:20, and 1:30, some with aeration (1:5 and 1:30). To determine damage, seeds were soaked in water for 0, 36, 60, and 96 hours and then agitated in a commercial hydroseeder for I hour, with samples removed at intervals. Germination in petri dishes was not affected by different ratios of seeds to solution varying from 1:1 to 1:30 if soaking was limited to 24 hours. With longer soaking the higher ratios decreased germination. Soaking for 36 hours in water before agitation did not alter seeds to the extent that damage was excessive even after 30 min in the hydroseeder. Damage of both soaked and dry seeds by cracking or rubbing was negligible at the agitation times normally used in hydroseeding. In field testing, seedling numbers were increased when seeds were presoaked with growth regulators. The technique of presoaking seeds in hydroseeders appears to be effective and practicable.
Effect of Photoperiod and Size at Flowering on Vegetative Growth and Seed Yield of Soybean1
Authors: Patterson David T. , Peet Mary M. , Bunce James A. 
Published: July 2010

AbstractIn comparisons of soybean [Glycine max (L.) Merr.] ‘Ransom’ from growth chambers and field plots, seed yield per plant was generally lower in the chambergrown plants. To determine the limiting factors, we studied the effects of photoperiod and plant size at flowering on final seed yield in controlled environment rooms at 26/20 C (day/night) temperatures. To obtain plants of three size classes at time of flowering, a 37‐day period of photoinductive 8‐hour days was used at three ages: (22, 30, and 38 days after planting; three, six, and nine main stem trifoliolate stages respectively). Delaying the beginning of photoinduction for 8 days increased total seed weight 34%. When photoinduction was delayed 16 days there was an 84% increase in seed weight. The increased yield was primarily associated with an increase in the number of axillary nodes produced as photoinduction was delayed. Delayed photoinduction had little effect on the average numbers of pods per node, numbers of seeds per pod, or weight of individual seeds. When the plants were grown under 16‐hour daily periods of full illumination, after photoinduction was completed, final seed yield was significantly greater than under 12‐hour daily periods of full illumination, but vegetative growth was not significantly increased. It was concluded that by controlling flowering times in chamber‐grown plants, seed yields per plant and per unit area could match similar yields in field plants.
Corn Forage Production in No‐Till and Conventional Tillage Double‐Cropping Systems1
Authors: Nelson L. R. , Gallaher R. N. , Holmes M. R. , Bruce R. R. 
Published: July 2010

AbstractDouble‐cropping systems involving feed grains are becoming increasingly important for the long growing season in the Southeast and to meet consumer demands for food. Therefore, corn (Zea mays L.) forage production and quality were evaluated in double‐cropping systems following wheat (Triticum aestivum L.) and barley (Hordeum vulgare L.). These systems were evaluated at two locations in Georgia Upper Coastal Plain (soil is member of the clayey, kaolinitic, thermic family of Typic Hapludults) regions. Variables in this study were no‐till (NT) vs. conventional tillage (CT), irrigated vs. non‐irrigated, and early vs. late planting date. Forage yields from corn NT planted in small grain stubble (harvested for silage) in April were about equal to those from CT‐planted corn. Corn forage yields when NT was planted in small grain stubble in mid‐June were reduced compared with that planted in April in the Coastal Plain Region of Georgia, while forage yields in the Piedmont Region were nearly equal for corn planted early and late. The lower yields of late planted corn were related to a lower percentage of ears in the forage than early planted corn. Forage yield increases due to irrigation varied from zero to over 100%, depending on season and location. A high forage yield potential for double cropped NT corn planted early (mid‐April) throughout the Southeastern USA is evidenced. With present varieties and known management, forage yields of late planted (June corn) will usually be lower than those for early corn in the Coastal Plain region.
Barley Yields and Tissue N, P, and K with High‐Low N Supply for Different Growth Periods1
Authors: Suzuki Michio , MacLeod L. B. 
Published: July 2010

AbstractGrain production with minimum use of N has been a major concern of producers. Since physiological characteristics of a barley plant having high N utilization efficiency (grain yield/supplied N) have not been fully elucidated, grain yields and chemical components of Herta barley (Horedum distichon L.) from hydroponic cultures with high and low N supply for different growth periods were determined. A high rate of N at 75 ppm was applied for 0 (check), 1, 2, 3, 4, 5, 6, 7, and 12 weeks after emergence and low rate of N at 20 ppm for the remaining period to maturity. The highest grain yield and N utilization efficiency occurred by supplying the high rate of N for 5 weeks after emergence. In the primary tiller of the productive and efficient plant at 9 weeks after emergence the leaf‐to‐stem‐N ratio was approximately 7:3, and the P concentrations of the fifth leaf was twice as high as of the second top leaf. This study suggests that an ideal N supply would involve applications of a low rate of N for 1 week after emergence, a high rate of N for the following 4 or 5 weeks until the first node of the stem becomes visible on the primary tiller and then a low rate of N for the remaining period to maturity.
A Technique of Monitoring Acidity of Silage during Preservation and Storage1
Authors: Sprague Milton A. , Taylor B. Brooks 
Published: July 2010

AbstractMeasurement of the rate of drop in pH of silage is important in research since it indicates the kind of fermentation which takes place. Ability to monitor pH changes without opening the silo permits a time‐development study of agronomic factors which affect the efficiency of preservation of different kinds of forages. pH electrodes were placed within plastic silos and electrode lead wires extended through the plastic to a portable pH meter outside. In addition, a KCI agar‐salt bridge was inserted and led to a calomel electrode outside the silo. Its perormance was compared closely with where both electrodes were placed in the silo (r = 0.995). The method is demonstrated with data from 12 silos of orchardgrass fertilized with 28, 140 and 364 kg/ha of N and harvested at early and late stages of maturity. Medium N forage harvested at late maturity attained a pH of 4.2 within 15 hours, whereas that harvested early required 2 days. High N forage of early maturity remained above pH 4.2 for 103 days and butyric acid was detected. Dry matter content of forage below 30% is required for best operation of the electrodes.
The Gompertz Function as a Model for Cotton Hypocotyl Elongation1
Authors: Pegelow E. J. , Taylor B. B. , Horrocks R. D. , Buxton D. R. , Marx D. B. , Wanjura D. F. 
Published: July 2010

AbstractSuccessful modeling of cotton (Gossypium hirsutum L.) seedling emergence requires a model capable of simulating hypocotyl growth under a wide range of soil environments. A previous model used an autocatalytic growth equation which was satisfactory for relatively favorable soil environments. We report here the use of the Gompertz equation as a hypocotyl elongation model which should have adaptability to greater environmental extremes than the autocatalytic model. A three parameter form of the Gompertz equation was applied to a comprehensive set of cotton hypocotyl elongation data, obtained over a range of steady‐state soil environments. The form used was y = A exp {—exp [b(c—t]} where y is hypocotyl length at time t, A is maximum (potential) hypocotyl length under prevailing soil conditions, b is the weighted mean relative growth rate, and c is the time at which maximum growth rate is attained. This function describes an asymmetrical sigmoid curve in which all parameters can be assigned physiological meaning. Best‐fit estimates of the Gompertz parameters were derived for hypocotyl elongation in each environment by a non‐linear least squares program. Multiple linear regression analyses of the estimated Gompertz parameters (in ) with soil temperature, physical impedance, and moisture were used to examine the influence of soil environment on the parameters. Each of the three Gompertz parameters were adequately described by a cubic regression model involving these soil factors. The regression models were used to develop a Gompertz model in which each parameter was responsive to fluctuating changes in soil environment. The model should be adaptable to simulating cotton hypocotyl elongation under a wide range of soil conditions, including those resulting in seedling stress.
Guttation Deposits on Turfgrass1
Authors: Duell Robert W. , Markus Denes K. 
Published: July 2010

AbstractThe infrequently observed, and insufficiently documented phenomenon of guttation and accumulations is herein related to environmental specifics to better comprehend responses observed. Three applications of 367 kg/ha of 10‐4.4‐8.3 were made at 12 and 13‐day intervals to low maintenance turfgrasses on a regraded field of sandy loam. The second of the series resulted in the accumulation of guttation deposits. The white solids were concentrated on the abaxial surface of the distal 1 to 1.5 cm of the tips of certain grasses. Deposits were most conspicuous on certain broad‐bladed cultivars of Poa pratensis and were confined to inconspicuous white spheres on the tips of blades of a large series of several species of Festuca and other turfgrasses. The absence of such deposits on the same grasses receiving similar fertilizer treatments 12 days earlier or 13 days later was attributed to their dissolution by rainfall after fertilization. No injury related to the deposits could be discerned; hence, no remedy is needed, but irrigation or the next rain will eliminate the deposits.
Temperature Gradient Effects on in situ Hygrometer Measurements of Water Potential1
Authors: Wiebe Herman H. , Brown Ray W. , Barker Jerry 
Published: July 2010

AbstractThe effects of temperature gradients on water potential measurements with various commercial and laboratory soil hygrometers were tested in a soil column at —18 bars or in a sponge column wetted with a —18 bar sodium chloride solution. Temperature gradients were induced in the medium by warming or cooling either the base or the top of the column for several hours. Hygrometers in which the measuring (wet) junction was located in the middle of the cylindrical sample surface gave small temperature gradient errors, less than 3 bars when the temperature gradient in the surrounding medium was 1 degree cm−1. Locating the measuring thermocouple near the base of the cylindrical sample surface gave errors ranging from 10 to 18 bars per gradient of 1 degree cm−1. Hygrometers with an “end window” sample surface gave errors ranging from 23 to 62 bars. Water potential readings were consistently too low (dry) when the sample surface was cooler than the measuring junction, and too high (near zero) when the sample surface was warmer. Accurate water potentials were obtained with all models when medium temperature was uniform. Double junction, so called “temperature compensated” units, gave the largest temperature gradient errors. The zero offset voltage of single junction models was a systematic function of the temperature gradient in the medium, and could be used as a warning that temperature gradients exist and in calibrating individual sensors.
A Flotation Method for Determining Root Mass in Soil1
Authors: Al‐Khafaf S. , Wierenga P. J. , Williams B. C. 
Published: July 2010

AbstractRoot weight is commonly determined as a criterion of root response to the environment. Determination of root weight by soaking soil and associated roots, and washing over sieves may result in losses of root material. In this study the distribution of cotton roots with depth and time was determined by soaking soil and roots in a solution containing 40 g/liter sodiumhexametaphosphate in a 1:5 soil solution ratio. The density of the resulting soil suspension was increased to 1.5 g/cm3 by adding dry, 78% pure CaCl2 in a ratio of 1 g CaCl2 to 2 g soil suspension. Roots floated to the surface and were skimmed from the surface with a fine wire strainer. By subsequent washing in tap water roots and organic debris ,were separated. Distributions of fine roots (mean diameter 0.25 mm) and total root mass for field grown cotton is shown at various times and depths.