bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of Cutting Date on Digestibility and Intake of Irrigated First‐Crop Alfalfa Hay1
Authors: Anderson M. J. , Fries G. F. , Kopland D. V. , Waldo D. R. 
Published: July 2010

AbstractDelayed cutting during the practical harvesting season of first‐growth forages raised in humid climates has resulted in a linear decline in the digestibility component of nutritive value. This study considered the effect of cutting date upon the digestibility and intake components of nutritive value of first growth alfalfa (Medicago sativa L.) raised under irrigated conditions at two altitudes in Utah and Montana. Duration of the study was 5 years with harvests occurring over ranges of 23 to 62 days. Intake and digestibility by total collection of each hay were determined with four sheep. Digestibility was determined during three years at both ad libitum and a controlled feeding level. Hays were harvested at Huntley, Montana for the first two years and at Logan, Utah for the remaining three years. The variety ‘Ranger’ was used during the first four years and ‘DuPuits’ and ‘Lahontan’ varieties were compared during the last year. Daily intake of dry matter decreased 0.21 g/kg BW¾ for each day of delay with large variations in rate of change for different year‐variety sets of data. Digestibility of the dry matter decreased approximately 0.28 percentage units per day for both Huntley and Logan hays, but Ranger alfalfa was about six percentage units more digestible on June 10 at Huntley than at Logan. Correlations between dry matter and energy digestibilities and between dry matter and organic matter digestibilities were 0.98 and 0.97, respectively. Crude protein concentration declined 0.20 percentage units per day. Digestible protein concentration of alfalfa forage can be expressed as a function of crude protein concentration by Y = −4.15 + 0.97X with r = 0.98.
Movement of Herbicides through Soil to Soybean Roots1
Authors: Don Scott H. , Phillips Ronald E. 
Published: July 2010

AbstractAbsorption of pesticides is one of the primary means by which pesticide residues enter the food chains of humans, domestic animals, and wildlife. Thus, a comparison was made between the theoretical and observed uptake of isopropyl m‐chlorocarbanilate (chlorpropham) and 2‐chloro‐4‐( ethylamino )‐6‐ (isopropylamino)‐s‐triazine (atrazine) from soil by soybean roots (Glycine max (L.)). The rate of absorption of both 14C‐herbicides as determined by liquid scintillation techniques was rapid initially and decreased as plant growth increased. These rate curves were approximately parallel throughout the growth range with the rate of absorption of atrazine being always greater than that of chlorpropham.The theoretical movement of the two herbicides to the root surface was calculated assuming certain boundary conditions for the system. Assuming the roots to be “perfect sinks,” the diffusion process accounted for the total quantity of herbicide absorbed except during the early hours following germination. As root growth increased, the roots became less of a sink for these two herbicides, and diffusion to a “perfect sink” could theoretically supply more than the amount absorbed. Assuming the rate of uptake to be proportional to the concentration at the root surface, a curvilinear rate constant was observed during the uptake period. The data indicated that the plant controlled the amount of herbicide accumulated as well as its principal transport mechanism to the root, probably through its influence on the permeability of the root or root saturation.
Effects of Gibberellic Acid and Sublethal Levels of Four Herbicides on the Cool‐season Regrowth of Two Tropical Forage Grasses1
Authors: Whitney A. S. , Green R. E. , Younge O. R. 
Published: July 2010

AbstractA series of experiments were conducted at two locations in Hawaii to evaluate the feasibility of increasing the cool‐season growth of pasture grasses by means of chemical sprays.In a preliminary trial from December to March, pangolagrass (Digitaria decumbens Stent) was treated with three levels of nitrogen (0, 56, and 112 kg/ha as (NH4)2SO4) and then with the following chemicals: ametryne, atrazine, simazine, and dicamba, each at 560 and 2240 g/ha; and gibberellic acid (GA) at 12 and 37 g/ha. Ametryne at 2240 g/ha reduced yields at the ll2‐kg N/ha level only. No other significant effects were noted, but there was some indication of a small non‐significant GA response.Kikiyugrass (Pennisetum clandestinum Hocht. ex Chiov.) was treated at two locations during February with three levels of N (22, 56, and 168 kg/ha as (NH4)2SO4) and then with simazine at 247 or 741 g/ha, GA at 62 g/ha, or simazine plus GA. Simazine did not affect yields except at the 168‐kg/ha level of N at the 640‐m elevation site; under this set of conditions, dry matter (DM) and crude protein (CP) yields were increased by 40% over the untreated control.Much larger increases in DM and CP yields were associated with GA treatment; relative increases were highest, up to 9‐fold, under low N levels, especially at the 900 m elevation site (av. soil temp. @ 5 cm ≤ 18 C). Absolute responses were highest, up to 2200 kg DM/ha, under high nitrogen levels and at the 640 m elevation. The GA treatment appeared to stimulate production by causing rapid increases in both photosynthetic area and stem tissue. The added stem tissue presumably provided additional carbohydrate “sink” capacity, thereby minimizing starch accumulation in the chloroplasts during daylight hours. Subsequent yields of GA‐treated swards harvested a second time were less than controls at the 900 m elevation but greater than the controls at the 640 m elevation.The limited response from the application of triazine compounds is in contrast to many previous reports. Our results indicate that they may be of only limited usefulness for tropical grasses, especially when the N is supplied in forms other than nitrate.In contrast, the application of 62 g/ha of GA may be a useful adjunct to nitrogen fertilization for increasing forage production during periods of moderate temperature stress.
Water Loss from an Irrigated Sorghum Field: II. Evapotranspiration and Root Extraction1
Authors: Stone L. R. , Horton M. L. , Olson T. C. 
Published: July 2010

AbstractTechniques for estimating evapotranspiration from water depletion within the soil profile frequently do not account for flux below the root zone. A method using tensiometers for obtaining evapotranspiration rates and root extraction patterns within an actively growing sorghum (Sorghum bicolor (L.) Moench) crop is discussed. Profile water depletion was calculated from water content profiles determined using tensiometer readings and laboratory‐measured soil water characteristics. Profile water depletion minus flux below the root zone yielded the daily evapotranspiration rate. During the 31‐day study, approximately 65% of the total water loss was due to evapotranspiration and approximately 35% was due to flux loss from the root zone. These data clearly show the importance of considering flux below the root zone when attempting to determine evapotranspiration rates using depletion methods. The method of determining evapotranspiration rates illustrated in this paper provides an alternative to the microclimatological and lysimeter methods.
Experimental Grassland Renovator1
Authors: Smith E. M. , Taylor T. H. , Casada J. H. , Templeton W. C. 
Published: July 2010

AbstractGrassy swards inevitably become deficient in nitrogen unless some measure is used to replenish the supply. Renovation is a process by which legumes may be introduced into grass‐dominant fields. The legumes serve to replenish the nitrogen and to improve the quality and quantity of forage produced.The main problems in grassland renovation have been to determine tillage and seed placement requirements and to develop methods to meet these needs. Basic research has shown that there is a high probability of success in establishing whlite clover (Trifolium repens) and alfalfa (Medicago sativa L.) in a Kentucky bluegrass (Poa pratensis L.) sod when the following tillage and seed placement requirements are satisfied: till a furrow 0.6 cm wide and 1.9 cm deep, place the seeds in this furrow, cover the seeds 0.6 to 1.2 cm deep, press the soil over the seeds, and spray a band of herbicide 10 cm wide over the seeded furrow.The once‐over renovator described in this note is designed to satisfy the specified requirements of tilling, seeding, cnltipacking, and spraying. Tillage is accomplished with power‐driven blades that float in a vertical plane to follow the land surface, while seed placement is achieved with small double‐disk openers. The machine is designed to operate on rough terrain such as is prevalent in many grassland situations.
Reflectance, Transmittance, and Absorptance of Light by Subcellular Particles of Spinach (Spinacia oleracea L.) Leaves1
Authors: Gausman H. W. 
Published: July 2010

AbstractThis study considered the premise that subcellular particles in leaves contribute to the reflectance (R) and absorptance (A) of near‐infrared (IR) (light 750 to 350 nm).Subcellular particles of spinach (Spinacia oleracea L.) leaves were differentially sedimented and resuspended in a buffered sucrose solution. A spectroreflectometer was used to measure R and transmittance (T) over the 500‐ to 2,500‐nm wavelength interval (WLI) on replicated aliquots of five preparations: buffered sucrose solution (control); chloroplast preparation; S1, sediment of chloroplast preparation supernatant; $2, sediment of S1 supernatant; and S3, sediment of S2 supernatant. Absorptance was calculated: A= 1 ‐ (R + T).All suspensions of particulates caused less R than the buffered sucrose solution over the 500‐ to 650‐nm WLI. The chloroplast preparation, compared with the buffered sucrose solution, increased R over the 750‐ to 950‐nm WLI.The chloroplast preparation, compared with the buffered sucrose solution, S2, and S3, decreased T over the 500‐ to 1,250‐nm WLI; SI decreased T over the 500‐ to 900‐ nm WLI.Compared with remaining treatments, the chloroplast preparation increased A over the 500‐ to 1,100‐nm WLI.Excluding the buffered sucrose solution, R and A increased and T decreased in the IR region as particle size increased.A conclusion was reached that subcellular particles in leaves contribute to the R and A of IR light.
Diurnal Variation in Nonstructural Carbohydrates of Sorghum sudanense (Stapf) as Influenced by Environment1
Authors: Lechtenberg V. L. , Holt D. A. , Youngberg H. W. 
Published: July 2010

AbstractSudangrass (Sorghum sudanense (Stapf) herbage (leaves plus stems) and leaves, with 0 and 140 kg/ha of N fertilizer, were sampled four times daily on 8 days and eight times daily on 3 days to i) measure the diurnal variation in several nonstructural carbohydrates, ii) relate carbohydrate trends to environmental conditions, and iii) determine the influence of nitrogen fertilization on diurnal carbohydrate changes.Reducing sugars and sucrose were extracted from freeze‐dried, ground tissue with alcohol. Starch in the residue was hydrolyzed with takadiastase. Ferricyanide, resorcinol, and phenol‐sulfuric acid procedures were used to quantitatively assay sugars in the extracts.Sucrose concentration in sudangrass herbage varied from 1.8% of the dry matter at 6 AM to 5.8% at 6 PM. Starch increased from 6.6 to 8.8% in the same period. Half of the daily increase in carbohydrate disappeared between 6 PM and 12 M. The diurnal trends in leaves were similar to those observed in herbage. Nitrogen fertilization (140 kg/ha) reduced the average total carbohydrate concentrations from 16.6 to 14.8% but did not change the magnitude of diurnal trends. Starch concentration declined from 9.9 to 5.9% of the dry herbage and sucrose increased from 1.2 to 6.6% during the 16‐day sampling period. This change was more pronounced in N‐deficient sudangrass. Rates of sucrose accumulation varied with radiation level and temperature, but the maximum concentrations reached each day were about 5.5%, indicating a physiological limit. A cold night caused the leaves to retain unusually high levels of sucrose overnight. Sucrose concentrations were as high as 2.5% compared to concentrations of less than .3% on warm nights. Sudangrass temporarily stores most excess photosynthate as sucrose in contrast to alfalfa (Medicago sativa L). which accumulates much more starch.
In situ Estimation of Alfalfa Forage Yields1
Authors: Burzlaff D. F. , Ham G. L. , Kehr W. R. 
Published: July 2010

AbstractAn electronic capacitance meter to estimate yields of forage in situ was developed and tested at the University of Nebraska, Lincoln. Use of this type of measurement leaves vegetation in a relatively undisturbed state with a potential for successive sampling at the same location. The forage meter permits estimation of growth rates over short periods of time as well as forage consumption under grazing. Prediction equations were developed for use of the machine in estimating first‐ and second‐cutting alfalfa (Medicago sativa L.) yields. Yield predictions of alfalfa varieties were obtained with the capacitance meter and compared to data obtained by conventional harvest procedures. The results indicated that yields of first‐ or second‐cutting alfalfa can be estimated by use of an electronic capacitance meter. Correlation coefficients (r) of .80 for first‐cutting and .73 for second‐cutting were obtained for estimating alfalfa yield in situ as compared to conventional harvesting procedures.
Response of Subirrigated Hay Meadows to the Application of Nitrogen, Phosphorus, and Sulfur1
Authors: Rehm G. W. , Moline W. J. , Sorensen R. C. , Burzlaff D. F. 
Published: July 2010

AbstractHay production from subirrigated meadows is an important part of the economy of several states. Although fertilization with N and P had been researched in separate studies, little attention had been directed toward the interaction effect of these nutrients on forage production and the grass‐legume composition of these meadows. This study was designed to evaluate the effect of five rates of N, P and S on the yield and grass‐legume composition of subirrigated meadows. Forage yields were recorded and separations made to determine grass‐legume composition. Yields increased linearly with applied N while the response to P was curvilinear. There was no response to S. The percentage of grass in the meadows increased with applied N. Legume percentages increased with added P. Grass yields showed a linear increase with applied N and a curvilinear response to added P. Legume yields decreased linearly at low P rates when high rates of N were applied but increased curvilinearly as P rates were increased. Throughout the study, combinations of N and P produced the highest yields, thus demonstrating the importance of the combination of these two nutrients for maximum production from subirrigated hay meadows.
Muskmelon Response to Rates and Sources of Nitrogen1
Authors: Wilcox Gerald E. 
Published: July 2010

AbstractThe method and rate of nitrogen fertilization of muskmelons (Cucumis melo) on sandy soils is of concern because of the leaching potential of N. The relative availability of nitrogen from ammonium nitrate, urea‐formaldehyde, and sulfur coated urea (SCU) was studied in the field with regard to influence on growth, leaf and petiole composition, and fruit yield of muskmelon. The field studies compared various nitrogen materials in different timing and rate schedules. The fertilizers were used at 0, 33, 66, 99, 132, and 264 kg/ha in single (preplant) and split (preplant + sidedressing) applications. Data were collected for 4 seasons. In each year N application increased vine growth and intensity of the green color of the leaves. The N concentration of the recently mature melon leaves was increased more by NH4NO3 than by urea‐formaldehyde or SCU. The relationship of N rate was linear with N composition but parabolic with yield. Optimum plant growth and fruit yields were obtained with a preplant application of 80 to 90 kg/ha. The same total N rate as a split application or as a less available N source was not as effective for fruit yield production. The increased yield from N treatment was due to increased vine size and increased numbers of fruit. Optimum fruit yields were produced at leaf composition of total N over 4.5% or petiole content of NO3‐N over 15,000 ppm during vegetative and fruit initiation stages. Sulfur coated urea with 37% dissolution rate produced NO3‐N and total N concentrations of petioles about equal to the same N rate as NH4NO3; SCU with 12% dissolution rate resulted in NO3 concentrations equal to one‐quarter the N rate as NH4NO3 at the runner stage and equal to one‐half the N rate as NH4NO3 just prior to harvest.Ammonium nitrate, a soluble, immediately available N source, applied in preplant at 80 to 90 kg/ha was the most effective treatment and resulted in optimum muskmelon fruit yields on sandy soils of southwestern Indiana in each year of the study.
Influence of Previous Crop on Nitrate Distribution in a Clay Soil Profile and Subsequent Response to Applied N1
Authors: Hipp Billy W. , Gerard C. J. 
Published: July 2010

AbstractCrop response to N can be difficult to predict under semitropical irrigated conditions. To aid in the explanation of erratice N response, studies were conducted over a 4‐year period to determine the influence of cotton (Gossipium hirsutum L.) and sorghum (Sorghum bicolor (L.) Moench.) on NO3‐N distribution in a clay soil profile and its effect on subsequent crop response to applied N. Double‐cropping systems used in the study were cotton— winter vegetable and sorghum—winter vegetable with plots split to include N rates of 0, 67, and 134 kg/ha. Nitrate nitrogen determinations were made periodically from soil samples taken from profiles of each treatment. Where sorghum was grown for 3 years, the profile was depleted of NO3‐N to a depth of 120 cm. In contrast, where cotton was grown NO3‐N accumulated at the 60 to 120 cm depth. This resulted in little response to residual N by mustard (Brassica juncea) after sorghum, but residual N from applications of 134 kg/ha per year to cotton precluded a response to N applied to winter mustard. These studies indicate that the depleted soil profile after sorghum results in a need for higher rates of N fertilizer on crops following sorghum than those following cotton.
Recovery of K2SO4 by Alfalfa After Placement at Different Depths in a Low Fertility Soil1
Authors: Peterson L. A. , Smith Dale 
Published: July 2010

AbstractKnowledge of the quantitative contribution of plant nutrients from the soil volume penetrated by crop roots is needed for an overall analysis of present methods of fertilization. An experiment was initiated in 1971 to determine the uptake of K and SO4 by alfalfa (Medicago sativa L.) from different depths in a low K Plano silt loam soil profile. An injection method was used to place a solution of K2SO4 at depths of 7.5, 22.5, 37.5, 52.5, 67.5, and 82.5 cm below the soil surface in a 2‐year‐old stand. A check and surface broadcast application of K2SO4 also were included as treatments. Potassium sulfate was applied at the rate of 224 kg/ha of K and 92 kg/ha of S. Treatment areas were 8350 cm2. Three cuttings of the entire treatment area were made at first flower during the 1971 season, and the herbage was analyzed for yield and concentrations of K and S.Alfalfa recovered 41, 29, 19, 16, 10, 15, and 11% of the added K from the surface, 7.5, 22.5, 37.5, 52.5, 67.5, and 82.5 cm soil depths, respectively. No major differences were observed in S concentration of the tissue between the check and treatments.These data show that alfalfa absorbed K most heavily from the surface soil area as compared to the Ap and deeper horizons.
Influence of Tobacco Plant Canopy on Percolation1
Authors: Terry D. L. 
Published: July 2010

AbstractThis study was conducted to investigate the relationship between percolation at various positions in Lakeland sand and Norfolk loamy sand soils under tobacco (Nicotiana tabacum L.) culture and the growth and development of the plant canopy. A procedure is described for making direct measurements of percolation at various positions at a depth of 30 cm in a soil with respect to plant location as follows: A) through a ridge directly below a plant; B) through a ridge half way between two plants; C) through a fallow ridge; and D) through a fallow level area. During the first 15 to 20 days of the season percolation was similar at all positions studied and amounted to 40 to 60% of an average rainfall. From about 40 days after transplanting to the end of the growing season percolation at position A was about 40 to 100% of the rainfall while that at B and C was near zero. Percolation at D was intermediate averaging around onehalf that of A. The large amount of percolation at A after canopy development was explained as the result of water being intercepted by the leaves and channeled to the base of the stalk. The results indicated that percolation and possible leaching below 30 cm in a tobacco field are significant during the early part of the season (15 to 20 days from transplanting or later); however, after canopy development (40 to 49 days from transplanting or earlier) they are probably not significant except in a small soil volume directly below the plants.
Evaluation of Herbicides in the Establishment of Alfalfa, Ladino White Clover, and Crownvetch1
Authors: Cope W. A. , Waldrep T. W. , Chamblee D. S. , Lewis W. M. 
Published: July 2010

AbstractFive experiments were conducted to determine the effects of herbicides on seedling injury and on weed control in the establishment of alfalfa (Medicago sativa L.), ladino clover (Trifolium repens L.), and crownvetch (Coronilla varia L.) in North Carolina. Six treatments with commercial herbicides were included in the series of tests, and a number of other commercial and experimental herbicides were included in one or more of the tests. Two of the five tests were spring seeded to determine the feasibility of using herbicides for successful spring seeding in the area as opposed to the standard practice of fall seeding. Each herbicide was tested in either a preplant incorporated, preemergence, or postemergence application. Herbicide effects were measured in terms of legume stands, vigor, and injury ratings. All the herbicides caused some injury but certain herbicides were only slightly injurious while giving excellent weed control. In prepllant incorporated applications, S‐propyl dipropylthiocarbamate (vernolate) and S‐ethyl dipropylthiocarbamate (EPTC) provided excellent weed control and insignificant injury to all legumes. The higher of two rates of vernolate and EPTC were only slightly more injurious to the legumes than the lower rates. Preplant incorporated treatments of N‐butyl‐N‐ethyl‐a,a,a‐triflouro‐2,6‐dinitro‐p‐toluidine (benefin), 4‐(methylsulfonyl)‐2,6‐dinitro‐N,N‐ dipropylaniline (nitralin), and a,a,a‐triflouro‐2,6‐dinitro‐N,N‐dipropyl‐p‐toluidine (trifluralin) generally gave low injury, but effects were variable for tests and legume species, especially at the higher rate. Postemergence treatment with 2‐sec‐butyl‐4,6‐dinitrophenol (dinoseb) caused little injury in certain tests but resulted in severe defoliation in others, with the least injury to alfalfa and the most to crownvetch. None of the herbicides used in preemergence applications gave good weed control without severe legume injury. There were no readily apparent differences between fall and spring effects of the herbicides. Injury to legumes in one test on sandy soil was generally greater than in the four tests on clay soil.