bluuebunny/crossref_metadata_2025 huggingface dataset:
Estimating the Nutritive Value of Forages Containing Tannin and Phenols by Chemical and Bioassay Methods1
Authors: Burns J. C. , Cope W. A.
Published: July 2010

Anti‐quality substances in crownvetch (Coronilla varia L.) and sericea lespedeza [Lespedeza cuneata (Dumont) G. Don] require that analytical methods show their presence and effect on nutritive value of these forages. This study compares a chemical and a bioassay (in vitro dry matter disappearance) method of estimating the nutritive value of six morphologically different crownvetch clones (separated into stems, petioles, leaflets and flowers) and three strains of sericea lespedeza (separated into stems and leaves).

The chemical method uses detergents to fractionate the fibrous constituents of forages. Use of the content of fibrous fractions in a summative equation provides an estimate of true digestible dry matter (EDDM). The bioassay relies on rumen microflora to degrade the forage sample, resulting in an in vitro estimation of dry matter disappearance (IVDMD).

When total phenol and tannin concentrations were high and fiber low (leaf tissue) agreement was lacking between the chemical and bioassay methods (crownvetch r = —0.22; lespedeza r = —0.38, harvest 1 and r = 0.04, harvest 2). The relationship between methods was significant (P ≤ 0.01) when total phenol and tannin concentrations were low and fiber (stems) of primary concern (crownvetch stems r = 0.93; lespedeza stems r = 0.59, harvest 1 and r = 0.77, harvest 2).

The chemical method was insensitive to either total phenol or tannin concentrations, whereas, the bioassay appeared sensitive to both structural constituents and the anti‐quality substances. Methods used to estimate nutritive values of forages that reflect only some of the quality constituents are of specific applicability and their indiscriminate use may lead to erroneous conclusions.
Returned Clippings and N Fertilization on Bahiagrass Herbage Production and Nitrogen and Organic Matter Contents of Soil1
Authors: Beaty E. R. , Tan K. H. , McCreery R. A. , Edwards J. H. , Stanley R. L.
Published: July 2010

Plot clipping has been the time honored method of evaluating forage fertility investigations. Evidence is available suggesting that clipping data are not predictive of nutrient needs of grazed pasture. The following research was conducted with the objective to observe the effect of returning herbage to pasture at various rates of N fertilization on herbage production, N and organic matter contents of soils.

A field experiment in a completely randomized split plot design, employing three replications, was conducted in 1966 and 1967 with Pensacola bahiagrass (Paspalum notatum, Flugge) grown on a Eustis loamy sand at 4 N rates. None to 100% of the harvested and dried forage was returned to the plots. Increases in forage yield due to forage return ranged from non‐significant when no N was applied to considerable increases as indicated by the steeper regressions as N application increased. Over the 2 years, application of 84 kg/N/ha together with returning the forage produced as much forage as 168 kg/N/ha in combination with removing it.

Returning the forage had minor influence on soil N and organic matter contents. Evidence obtained suggested that mineralization and availability of recycled nutrients to a sward is probably a long‐term affair when available N is low. N applications appeared to appreciably shorten the length of time required for returned forage to offer advantage to the sward. The evidence presented indicated that both high forage yields and maximum improvement of soil fertility in the Eustis soil could be achieved when 40 to 60% of the bahiagrass herbage were returned to the pasture accompanied by large application of N fertilizers.
Plant Growth Regulator Effects on Flowering of Poa pratensis L. under Field Conditions1
Authors: Buettner Mark R. , Ensign R. D. , Boe A. A.
Published: July 2010

The imminent ban on fall burning of Kentucky bluegrass (Poa pratensis L.) residues has threatened the grass seed industry with subsequent reductions in yield. In order to assess the use of plant growth regulators as a potential alternative to burning, eight chemicals were applied at two developmental growth stages of unburned plots of Kentucky bluegrass. Information on panicle emergence, panicle number, and seed weight was recorded. Applications of growth regulators were made in autumn to ‘Merion,’ ‘Fylking,’ and ‘Nugget,’ and in spring to ‘Park’ and ‘Baron.’ All treatments were applied during the second seed crop year.

Growth regulator applications affected flowering in Merion more than in the other cultivars. Terbacil, 3‐tertbutyl‐5‐chloro‐6‐methyluracil; chlormequat, (2‐chloroethyl)‐trimethylammonium chlorides; and ethephon, (2‐chloro‐ethyl)‐phosphoric acid, increased panicle numbers in Merion by 84, 73, and 70% above controls. Simazine, 2‐chloro‐4, 6‐bis‐(ethylamino)‐5‐triazine, increased panicle numbers in Fylking and Nugget by 71 to 56%. Seed weight in Merion was increased by 11% after gibberellin (Potassium gibberellate) application. Terbacil and bromacil (5‐bromo‐3‐sec‐butyl‐6‐methyluracil) applied to Park and Baron decreased panicle numbers. Gibberellin, ethephon, chlormequat, and simazine autumn applications delayed panicle emergence. Bromacil and 2,4‐dichlorophenoxyacetic acid) spring applications to Baron delayed panicle emergence. Gibberellin, ethephon, and bromacil spring applications hastened panicle emergence in Park. Increased Kentucky bluegrass seed yields are possible with selective plant growth regulators, primarily due to increased panicle numbers and seed size.
Nondestructive Method for The Determination of Boll Surface Area in Cotton1
Authors: McMichael B. L. , Elmore C. D. , Cathey G. W.
Published: July 2010

Fruit (boll) transpiration rates in cotton (Gossypium hirsutum L.) may be important in boll growth and movement of materials into developing bolls. Therefore to facilitate comparisons of transpiration rates of different age (and size) bolls, a nondestructive method for the estimation of cotton boll surface areas was evaluated using two commercial cultivars grown in the greenhouse. Boll length was linearly related to boll area for both ‘Stoneville 213’ and ‘Deltapine 16’ cottons by an equation of the form LOG10Y = a + b LOG10X, where a and b are regression coefficients, and Y and X are boll area and boll length, respectively. Since no significant differences were found between the individual equations for the two cultivars, a composite regression equation was computed which can be used for boll area estimations for both cultivars.
Relationships and Uses of Yield Components in Safflower Breeding1
Authors: Abel G. H.
Published: July 2010

An understanding of the interrelationships of growth characters is needed to improve breeding of safflower, Carthamus tinctorius L. The objectives of the study were to evaluate five plant characters and four seed characters as units of selection and to determine the optimum combination of years, locations, and dates of planting for testing cultivar performance.

Indirect yield components (plant height∕plot, canopy depth∕plant, canopy width∕plant, and head diam∕plant) were intercorrelated. They were also correlated to seed yield and to seeds∕head but with the exception of head diam∕plant they were not correlated to seed weight. The direct yield components (heads∕area, seeds∕head, and seed weight) were not intercorrelated but they were all correlated to seed yield.

In several tests involving seven cultivars, variance components were usually significant for plant height, heads∕section, and seed weight and usually nonsignificant for canopy depth, head diameter, and seeds∕head.

Cultivar × date of planting and cultivar × location interactions were generally nonsignificant. However heads∕section, seeds∕head, and seed weight showed significant interactions of cultivars with location and date of planting and made it evident that a single year's testing did not adequately evaluate these effects. Cultivar × year interactions were not significant when the data from only one location, Mesa, were analyzed. However when all three locations were considered, some significant interactions appeared.

Expected variances of varietal means for heads∕section, seed yield∕section, and seed yield∕plot were calculated for all combinations of environments and also extrapolated to six replications. Expected variances were virtually identical for the second and third years and second and third planting dates. Satisfactory precision for these characters was obtained for the cultivars tested using the combination of 2 years, two locations, two dates of planting, and four replications.
Mitochondrial Efficiency of Individual Alfalfa Plants as Related to Forage Yield1
Authors: Schneiter A. A. , McDaniel R. G. , Dobrenz A. K. , Schonhorst M. H.
Published: July 2010

The mitochondrial efficiency (ADP:0 ratio) of 5‐day‐old alfalfa (Medicago sativa L.) seedlings has been positively correlated to forage yields of similar lines grown in the field. The present technique used for selection of genotypes having high mitochondrial efficiency in alfalfa is limited because alfalfa is a very heterogenous crop and an evaluation of individual genotypes cannot be made using the large number of seedlings required for adequate sample. Objectives of this study were to 1. devise a technique for determination of ADP:0 ratio on an individual plant basis and 2. determine if a relationship existed between forage yields of individual genotypes and their mitochondrial efficiency.

ADP:O ratios were obtained on an individual plant basis, by the extraction of mitochondria from etiolated stem + petiole tissue. A significant positive correlation was found between ADP:O ratios and field forage production of identical genotypes. No correlation was found between etiolated regrowth and ADP:O ratios of comparable genotypes.

The technique for the selection of individual genotypes having high yield potential, by the use of mitochondrial efficiency evaluations, could serve as a valuable screening tool for plant breeders. This technique would allow both an increase in the magnitude of the population evaluated and a more efficient utilization of field research time and effort by the prior elimination of genotypes having low yield potential.
Response of Sugarcane to Filter Press Mud and N, P, and K Fertilizers. II. Effects on Plant Composition and Soil Chemical Properties1
Authors: Prasad M.
Published: July 2010

The effect of filter press mud (FPM) on the composition of macro‐ and micronutrients of sugarcane leaf has not been studied. Therefore eight field experiments, four plant cane and four ratoons, were conducted to study the effect of FPM and N, P, and K fertilizers and their interaction on leaf N, P, and K content of sugarcane (Saccharum officinarum L.). The effects of FPM and P‐fertilizer on leaf Ca, Mg, Zn, Fe, Mn, Cu, B, Mo, and Al content, as well as on extractable soil P, K, Ca, Mg, Zn, Mn, and Al, and on pH were also studied. These experiments were conducted over 2 years on seven sites. A split plot design was used with FPM on main plots (rates were 0, 20, and 40 metric tons/ha or 0 and 34 metric tons/ha dry wt with two or four replications) and N, P, and K fertilizer rates on subplots (two or four replications). The rates of fertilizers were as follows: N = 0, 94, and 188 kg/ha or 47, 94, and 141 kg/ha; P = 0, 45, and 90 kg/ha or 0 and 45 kg/ha; K = 0 and 112 kg/ha.

Filter press mud increased leaf N in one experiment while N‐fertilizer increased it in all experiments. In two experiments there were significant FPM ✕ N interactions. Filter press mud and P‐fertilizer increased leaf P in six and seven experiments, respectively. Significant interactions on leaf P were FPM ✕ P, FPM ✕ N, and FPM ✕ K. At the rates tested FPM‐P was a more efficient source of P than fertilizer‐P. Filter press mud increased the leaf K significantly in three experiments. Leaf Ca and Mg were increased as a result of FPM application in two experiments and one experiment, respectively. Extractable soil Ca and Mg values were similarly increased as a result of FPM application in all four experiments.

Filter press mud reduced leaf Al in four experiments, leaf Zn and Fe in two experiments, and leaf Mn in one experiment. P‐fertilizer applied together with FPM did not further reduce Zn or Fe in the leaf. Extractable soil Zn was increased as a result of FPM application and ex‐changeable A1 was reduced. Filter press mud slightly increased soil pH. Leaf Cu, B, and Mo were not affected by FPM or P.

These results showed that FPM was a more effective source of P than triple superphosphate at the rates tested, and that FPM could be used as a substitute for K fertilizers where a maintenance dressing is required. Filter press mud also supplied secondary nutrients but it has no consistent effect on micronutrient nutrition.
Woollyleaf Bursage Control with Monosodium Methanearsonate and Tillage1
Authors: Smith D. T.
Published: July 2010

Woolyleaf bursage (Franseria tomentosa Gray) infests approximately 70,000 ha of cropland in Great Plains states. Since susceptibility of this weed to MSMA (monosodium methanearsonate) was observed, MSMA and DSMA (disodium methanearsonate) were investigated under several conditions for control of woollyleaf bursage. The most effective control occurred when MSMA was applied in mid to late May after all shoots had emerged in the spring. Experiments were conducted in playa lakebeds on Randall clay (Udic Pellusterts). Woollyleaf bursage was consistently more susceptible to MSMA than DSMA. Roots were killed to depths of 30 cm or more. Mold‐board plowing of infested areas delayed, rather than reduced, shoot emergence. In contrast, a disking operation allowed weed shoots to emerge earlier and more uniformly, which resulted in greater effectiveness of MSMA. Soil moisture and crop yields were increased when MSMA was applied to woollyleaf bursage before planting cotton (Gossypium hirsutum L.). One year after treatment with MSMA, woollyleaf bursage control was still evident and sudangrass [Sorghum sudanense Stapp (‘Piper’)] yields were increased in treated areas.
Growth and Composition of Sudangrass on High‐Calcium, Low‐Magnesium Soil1
Authors: Fine L. O. , Shannon D. G.
Published: July 2010

Unsatisfactory growth of monocot crops on irrigated areas of Haverson soil, which is classified as a Ustic Torrifluvent fine‐loamy mixed (calcareous), mesic, and known occurrence of Mg deficiency and grass tetany in the area encouraged the authors to undertake this study. The objectives in the work were to determine plant performance through a considerable range of soil Ca:Mg and establish, if possible, minimum soil Mg levels for adequate nutrition of Sudangrass (Sorghum sudanense L.), an important forage of the area. ‘Piper’ sudangrass was grown in a greenhouse on three soil sources from the area: 1) surface soil previously Mg‐treated, 2) surface soil, 3) subsurface. The sources were all very slightly calcareous and had ratios of extractable Ca:Mg as high as 30:1 and as much as 4.5 meq exchangeable K/100 g. Mg was added at rates of 0, 2, 4, 8 meq, and K at 0 and 2 meq/100 g soil to attempt a remedy of field‐observed chlorosis and poor yields. Iron sulfate foliar sprays were used periodically to alleviate an iron chlorosis which developed in most cultures in the experiment. The Mg content of tissue grown on untreated soil ranged from 0.13 to 0.20%, generally one‐third to one‐half the Ca content. Soil K additions increased plant Ca content considerably and without exception, and increased plant Mg content in the second and third harvest with all three soil sources. Soil Mg additions increased plant Mg as much as three‐fold, but depressed Ca appreciably only with the topsoil having field‐applied Mg a year previously, and only slightly at harvests 1 and 2 with the other two soil sources. Mg depressed plant K in harvests 1 and 2. Plant Mg and K contents increased approximately proportional to soil additions of these ions. Plant materials harvested were generally below suggested minimums of Mg content for grass tetany control, and the K/Ca + Mg meq ratio exceeded 1.80. Results of these investigations indicate that for sudangrass forage of satisfactory quality, extractable Mg should be raised by soil additions to one‐half or equal the soil K when conditions of extractable Ca and K similar to these are found. Although yields were not affected the first harvest, Mg content of forage was increased and yields and Mg were both improved in subsequent harvests. Additions to bring Mg equal to native soil K and reduce Ca:Mg to 10:1 resulted in forage Mg content above 0.20%.
A Versatile Generalized Computer Program for Generating Calcomp Plots of Data Points, Histograms, and Functions1
Authors: Fribourg Henry A. , Hannaway David B. , Patterson Virginia K.
Published: July 2010

A FORTRAN IV program using CALCOMP drum plotter routines was written, incorporating the features present in two programs previously reported by other authors and adding other capabilities. Rectangular graphs can be prepared with one or two X axes and one or two Y axes, and each pair of parallel axes may be drawn at different scales. Several lines of descriptive labeling are possible for both horizontal and vertical axes. Data points may be plotted either as histograms with or without hatchings or as individual symbols. The symbols may be isolated or connected with dots, dashes, or combinations of dots and dashes in different lengths. Plots can be generated for numerous functions representable in Cartesian coordinates. The resulting graphs are suitable for publication.
Responses of Red Clover to Increasing Rates of Topdressed Potassium Fertilizer1
Authors: Smith Dale , Smith R. R.
Published: July 2010

High yields of legumes require large amounts of soil K. The purpose of this study conducted at Arlington, Wis. (43.7° N Lat) was to determine the amount of topdressed K needed to obtain maximum herbage yields from red clover (Trifolium pratense L.). ‘Lakeland’ red clover was established on low K Typic Argiudoll (Plano silt loam) soil and topdressed during spring of the second year with 0 to 896 kg/ha of K as KCl. The three highest K rates also were applied in split applications with half topdressed in fall and half in spring. There was no advantage to splitting K rates between fall and spring. No significant differences in herbage yield were observed in response to the application rates of K. However, yields tended to decrease with the 672 and 896 kg K/ha spring applications. Analysis of the second‐year total herbage showed that concentrations of K and Cl increased with K topdressing rate, but concentrations of total nonstructural carbohydrates, N, P, Ca, Mg, Na, Cu, Zn, B, Sr, and Mn decreased. There was no effect of K fertilizer on concentrations of S, Fe, Al, and percentage of IVDDM. Residual herbage yields and stands in the third year, following a severe winter, increased steadily up to 336 (stand) or 448 kg/ha (herbage yield) of spring applied K. Alfalfa (Medicago sativa L. cv. ‘Vernal’) with similar spring K applications on adjacent plots yielded less than red clover at all K rates. Even so, red clover yields were not increased as much as those of alfalfa by the topdressed K. Possibly red clover needs less K for maximum growth than alfalfa, or that at low soil K levels, red clover is better able to absorb K from the soil because of its profuse surface rooting.
Effect of Plant Growth Regulators on Reproduction of ‘Starr’ Spanish‐type Peanuts
Authors: Ketring D. L.
Published: July 2010

Successful use of plant growth regulants to increase yields of leguminous field crops has not been achieved. Only a few substances have been tested on peanut (Arachis hypogaea L.) plants. Four diverse plant growth regulators were tested on ‘Starr’ Spanish‐type peanut plants to 1) determine their effects on growth and yield components, 2) establish an optimum time for regulant application, and 3) ascertain any residual effects on germination of the seeds produced. The regulants were applied at either early or late‐flowering to plants grown in the greenhouse. When treatments were applied at early‐flowering, shoot fresh weight at harvest was reduced by morphactin, but increased by abscisic acid and picloram plus 2,4,5‐trichlorophenoxyacetic acid. None of the substances affected growth in the late‐flowering treatment. There was no apparent relationship between vegetative growth and weight of mature seeds produced.

Cumulative flowering patterns were altered by some of the substances and the continuous, prolonged flowering of these indeterminate plants was prevented. Pegging was stimulated by morphactin, but there was a wide range within which flowering and pegging could proceed without significantly affecting yield.

Treated plants produced seeds with altered germination. Seeds from morphactin‐treated plants germinated abnormally, and they had low ethylene production rates; the percentage of rapidly growing (vigorous) seeds was reduced. The percentage of vigorous seeds from plants treated with abscisic acid and 2.5 ppm of herbicide was also reduced.
Post‐harvest Heating and Survival of Sod as Influenced by Pre‐harvest and Harvest Management1
Authors: Darrah C. H. , Powell A. J.
Published: July 2010

Harvested turfgrass sod is a highly perishable commodity. Decline in quality and even death can occur if sod is not transplanted within a relatively short time. Respiratory heating is assumed to be the major deleterious effect occurring within the sod mass.

Simulated storage conditions were employed to study the post‐harvest heating, carbohydrate response, and survival of a Kentucky bluegrass (Poa patensis L.) ‐ red fescue (Festuca rubra L.) sod. Mowing height, nitrogen fertility, clipping residue, and mowing interval were preharvest techniques investigated. Time of harvest and cutting depth were evaluated as harvest techniques.

Sod which was 28C when placed into storage heated to 39C after 72 hours. During the storage period carbohydrates declined from 21.8 to 10.7%. Increased storage time resulted in significantly less top and root regrowth after transplanting. Low mowing heights, low nitrogen fertility, and clipping removal contributed to less heating during storage. Sod mowed at 7.6 cm heated to 46C after 72 hours of storage. Sod grown under low N fertility heated to 41C while high nitrogen sod heated to 44C after 72 hours of storage. Clipping removal vs. nonremoval accounted for a 4C differential in storage temperature after 48 hours. Mowing interval had no significant effect on storage temperature.

Early morning harvest resulted in the lowest storage temperatures and greatest survival. A temperature difference as great as 14C was measured between sod harvested at 0600 and 1500 hours. Decreasing the amount of soil between layers of sod contributed to higher temperatures during storage. Thin cut sod heated to 47C while sod cut to a depth of 1.9 cm heated to 38C after 72 hours.

The detrimental effects of high temperatures encountered during sod storage can be reduced. Lowest storage temperatures occurred when sod was harvested in early morning. Removal of active biomass from the sod stack was also an effective means of limiting storage temperatures. Treatments which contributed to the generation of more heat during storage suffered the greatest loss of live turf
Effect of Tillage Methods and Phosphorus Fertilization on Maize in the Humid Tropics1
Authors: Kang B. T. , Yunusa M.
Published: July 2010

The recent interest in the adoption of minimum tillage for crop production in the humid tropics for better soil and water conservation has raised questions concerning crop yield and nutrient absorption. There is lack of information on the most suitable method of P application with minimum tillage as compared to conventional tillage with tropical soils. The present study was therefore undertaken to investigate the interaction between soil tillage and P application methods on (a) P movement in the soil profile, (b) maize root distribution, (c) P content, and (d) maize yield.

The experiment was conducted on Egbeda soil series (Oxic Paleustalf) in southern Nigeria in 1974 and 1975 using a split‐plot design with four replications. Conventional and minimum tillage were the main plots, P rates and placement were the sub‐plots.

Root density of maize was increased with P application. There was a tendency of higher root concentration in the upper 10 cm of the soil surface with minimum tillage. Movement of broadcast P in the soil profile was observed to be slow with minimum tillage. However, broadcast, band, and hill methods of P application was observed to be equally effective in supplying adequate P to the maize crop at P rates of 20 kg P/ha on the Egbeda soil. Therefore, no effect of P placement method on maize yield was observed with both minimum and conventional tillage methods. The lower maize yield with minimum tillage in 1974 was attributed to early N‐ stress. In 1975 with 160 kg N/ha, maize yield was equal with conventional and minimum tillage methods.
Modification of a Hay Baler for Applying Organic Preservatives to High Moisture Hay1
Authors: McNemar J. H. , Sheaffer C. C. , Clark N. A.
Published: July 2010

In much of the United States the limiting factor in making good quality hay is the amount of time required for hay curing. The object of this research was to modify a conventional twine‐tie baler to apply liquid preservatives to high moisture hay in order to decrease field drying times.

Alfalfa‐timothy (Medicago sativa L. — Phleum pratense L.) hay was field treated with ammonium isobutyrate using a modified baler equipped with nozzles, pump, and storage tank. The preservative was applied at rates of 1.5, 2.0, and 3.0% to hay with an average moisture content of 39% with a range of 36 to 50%. All applied rates of preservative reduced storage temperatures. The baler modifications allowed for effective application of an organic preservative under field conditions.
Anhydrous Ammonia Compared to Ammonium Nitrate on Cool‐Season Grasses1
Authors: Schou J. B. , Tesar M. B.
Published: July 2010

Nitrogen fertilization of perennial grasses would be more widely accepted in the humid temperate part of the USA if it were more profitable. Currently the total cost of injecting NH3, anhydrous ammonia (AA), into sod is less than broadcasting ammonium nitrate (AN) but application technology and effects of AA on grasses are meager. These two N sources were compared in the field on deep‐rooted grasses—bromegrass (Bromus inermis Leyss) (SB), reed canarygrass (Phalaris arundinacea L) (RC), tall fescue (Festuca arundinacea Schreb.) (TF), and orchardgrass (Dactylis glomerata L.) (OG)—and on Kentucky bluegrass (Poa pratensis L.) (KB), a short‐rooted grass. Grasses were evaluated for seasonal and total yield, efficiency of N use, % stimulation between AA rows, and injury from AA in a 2‐year period (YR 1 + YR 2) after N fertilization of a Conover loam (Udollic Ochraqualfs; fine loamy, mixed, mesic). N was applied to the five grass sods only in the first year at at rates 112, 224, 448, and 896 kg/ha as surface‐broadcast AN or AA injected 13 cm deep into sods at row spacing of 25, 51, 76, and 102 cm. AA was slower than AN in increasing yield: in YR 1, AA produced lower yields in the first and higher yields in the last cutting than AN; in YR 1, yields were lower with AA but, except at the lowest N rate, were higher with AA in YR 2. Total yields increased with higher rates of N and were similar at all rates with either N source on all grasses except KB which yielded more with AA than AN at the highest rate. First‐year yields on all grasses plateaued at 224 kg N but increased with higher N rates in YR 2. Increasing AA spacing did not affect total yields but decreased yields in YR 1, particularly with KB, and increased yields in YR 2. Average yields in % were: SB‐100, TF‐86, RC‐79, OG‐75, and KB‐56. RC was the most efficient user of N. We concluded that AA is a feasible and efficient N source on perennial cool‐season grasses at rates up to 224 kg N/ha. Row spacings of 51 and 76 cm with special knives are suggested for shallow and deep‐rooted grasses, respectively.
Control of Witchgrass in Fields of Seedling Kentucky Bluegrass1
Authors: Robocker W. C. , Canode C. L.
Published: July 2010

Competition by witchgrass (Panicum capillare L.) in newly planted fields of Kentucky bluegrass (Poa pratensis L.) reduces vigor and stand of bluegrass seedlings and may significantly reduce seed yields the first harvest year. In some years a seeding may be lost. Control of witchgrass during seedbed preparation is impossible because bluegrass is a cool‐season grass that should be planted early, particularly in non‐irrigated areas, while witchgrass is a warm‐season species that emerges 3 to 4 week after bluegrass. Use of selective herbicides is thus the only feasible means of controlling witchgrass.

In a preliminary screening trial of 10 herbicides, only MSMA (monosodium methanearsonate) showed acceptable selectivity. MSMA at rates ranging from 0.6 to 5.6 kg/ha was applied on irrigated Kentucky bluegrass seedings in a Typic Haploxeroll (Garrison gravelly loam) soil. Witchgrass seedlings ranged from two to four leaves through six to ten tillers of growth, and bluegrass development was from one to two leaves through five to seven tillers. Three consecutive years of replicated field trials showed that seed yields tended to increase with increasing control of witchgrass. Treatment with 3.4 to 5.6 kg/ha of MSMA when witchgrass had begun rapid growth (more than two tillers) provided excellent control of witchgrass with no injury to Kentucky bluegrass seedling.
Soil Oxygen and Temperature Effect on Tetany Potential of Three Annual Forage Species1
Authors: Elkins Charles B. , Hoveland Carl S.
Published: July 2010

Grass tetany, a metabolic disorder of cattle on pasture, has often been related to low Mg and high K levels, and high K/(Ca+Mg) equivalent ratios in forages. These forage mineral imbalances often occur during wet periods when soil O2 may be low. The effect of 2, 4, 8, 16, and 21% soil air O2, on Ca, Mg, and K contents of rye (Secale cereale L.), ryegrass (Lolium multiflorum Lam.), and arrowleaf clover (Trifolium vesiculosum Savi) was studied in the growth chamber at 22 C day air temperatures and 12 or 16 C night temperatures.

Increasing soil O2, had little effect on Ca or Mg content of rye forage but increased K from 2 to 5%, and increased the K/(Ca+Mg) ratio to over 4. Uptake of K, Ca, and Mg was generally lower at 12 than at 16 C. Ryegrass forage, grown at increasing soil air O2, had higher K, Ca, and Mg contents. Concentrations of K, Ca, and Mg in ryegrass were lower at 12 than at 16 C. Magnesium levels at 2 to 16% soil O2 were below the critical level of 0.2% at 12 C air temperature. Soil O2 had little effect on the composition of arrowleaf clover forage, except for a small increase in K.

These results indicated that ryegrass forages, grown on poorly‐drained soil would likely be more tetany‐prone than that grown on well‐drained soil. However, rye forage would be more tetany‐prone when grown on well‐drained soil. The high Mg levels of arrowleaf clover showed its value in balancing tetany‐prone grass forage when it is maintained in a pasture.
Temperature and Oxygen Effects in Soil on Nutrient Uptake in Jojoba Seedlings1
Authors: Reyes D. M. , Stolzy L. H. , Labanauskas C. K.
Published: July 2010

Jojoba (Simmondsia chinensis), a woody shrub, produces seeds which have several potential uses. The objectives of this experiment were to study the effects of soil temperature and soil oxygen supply on the nutrient uptake of the jojoba plant. Presently, there is little information on effect of soil physical factors on plant nutrients.

The study was conducted in a greenhouse with constant temperature tanks to maintain root temperatures at 21, 27, and 33 C. Soil oxygen supply to the roots was controlled by controlling the concentration of oxygen in the atmosphere above the soil columns. Plants grown at a 33 C soil temperature produced significantly more dry weight than plants at 21 or 27 C. Concentrations of N, P, K, Na, Mn, and Fe in the leaves of plants grown at 33 C were substantially higher than leaves grown at 21 or 27 C. In general, nutrient concentrations in roots and total amount in plants were higher in plants grown at 33 C than at 21 or 27 C.

The two lowest levels of soil oxygen supply to the roots (1.5 and 6.5%) significantly reduced dry weight of leaves, stems, and roots compared to plants grown at oxygen levels of 12 and 21%. Decreased soil oxygen significantly reduced the concentration of K, Ca, Mg, Zn, Mn, and B in leaves while concentrations of N, Na, and Fe were increased. Concentrations of N, P, K, Mg, Na, B, and Fe in roots grown under low soil oxygen were less than plants grown with 21% oxygen. Low levels of soil oxygen significantly increased concentration of Na in leaves and stems and decreased the concentration in the roots. This study indicates that growth and nutrient uptake of jojoba is best at higher temperatures in well‐aerated soils.
Photosynthesis of Sugarbeets under N and P Stress: Field Measurements and Carbon Balance1
Authors: Cary J. W.
Published: July 2010

Advances in crop management are limited by our inability to recognize changes in growth resulting from short‐term fluctuations in plant environment. Simple, rapid, and nondestructive methods are needed to indicate daily and hourly rates of growth under field conditions. Because plant carbon balance is one possible approach to this problem, CO2 gas exchange parameters were measured on Beta vulgaris leaves of field‐grown plants to learn whether or not they might signal the onset of nitrogen and P stresses. The sugarbeets were grown on field plots of Portneuf silt loam (Xerollic Calciothid) soil and allowed to develop severe N and P stresses. Carbon dioxide exchange and stomatal resistance of intact plant leaves were measured with small leaf chambers during 1‐min periods. Leaf water potentials were also measured in the field with a hydraulic press. The CO2 compensation points, dark respiration, and osmotic pressures of excised leaf tissue were measured in the laboratory by standard methods. Photosynthesis per unit leaf area was reduced in advanced stages of N deficiency; however, none of the measurements satisfactorily indicated the onset of N or P stress because of heterogeneity between leaves. Calculations using the daily carbon balance of an average plant predicted the relative effects on root yield of 1) photosynthetic rate per unit leaf area, 2) photorespiration, 3) stomatal resistance to gas diffusion, 4) mesophyll resistance to carbon dioxide transfer, 5) size of the seedling tops in the spring, 6) partitioning of photosynthate between tops and roots near the end of the season, and 7) date of full plant cover. While all these factors are important, advances that can be made by manipulating most of them are limited. Increasing photosynthesis by reducing mesophyll resistance appears to offer the greatest potential for large yield increases.
Control of Weeds in Non‐Cultivated, Narrow‐Row Sorghum1
Authors: Burnside O. C.
Published: July 2010

Recent increased awareness of our finite energy supply and concern about our diminishing farm labor supply has stimulated the reexamination of production methods of sorghum [Sorghum bicolor (L.) Moench] in the Great Plains. Objectives of this research were to increase sorghum yields with the use of narrow‐row culture and improve weed control while reducing labor, energy requirements, and production costs. Improved weed control methods in sorghum developed during the past decade have facilitated reduced tillage methods of producing sorghum. Experimental results indicate the feasibility of producing grain sorghum in narrow rows without cultivation under non‐irrigated conditions on a Sharpsburg silty clay loam (Typic Argiudoll) at Lincoln, Neb. Selective control of annual broadleaf weeds was more readily accomplished than the control of grass weeds. Early weed control was most important in eliminating sorghum losses from weeds. Sorghum kept weed‐free the first 4 weeks after planting suffered no yield loss from subsequent weed growth. Herbicide treatments applied preplant incorporated, preemergence, or early postemergence selectively controlled annual weeds and resulted in sorghum yields equivalent to those on handweeded plots. The sorghum producer has the possibility of achieving higher sorghum yields when the crop is grown in narrow rows while reducing tillage, labor, and energy requirements in his production system.
Developmental Basis of Maturity Differences in Spring Wheat1
Authors: Halloran G. M.
Published: July 2010

Characterization of the developmental basis of maturity of spring wheat (Triticum aestivum L. em Thell) was sought in studies of the range of vernalization and photoperiodic responses in a number of spring wheats.

Vernalization responses of 12 spring wheat cultivars of Australian and overseas origin were evaluated as final leaf number of plants after cold treatment of germinated seedlings at 4 C for weekly intervals from 0 to 6 weeks. With the exception of the wheats ‘Bordan’ and the fixed crossbred ‘KB’ each genotype exhibited a marked response to cold treatment as decreased final leaf number; each appeared to attain its threshold response to cold within the 6‐week period of treatment. The behavior of two pairs of cultivars, ‘Insignia 49’ and ‘Early Summer Insignia 49’, and ‘Thatcher’ and ‘Winter Thatcher’, each pair believed to be near‐isogenic except for the presence and absence of vernalization response, indicated the likelihood that the possession of vernalization response, as such, was of no apparent significance in influencing final leaf number, spikelet number, and days to ear emergence under normal sowing times of spring wheat in southern Australia.

Variation in photoperiodic response within and between genotypes was examined under two daylengths — that of a normal field sowing and that of an extended photoperiod (18‐hour). Photoperiodic response was shown to be likely of major significance in determining maturity of spring wheat grown in southern Australia. Reasonably high correlations were obtained between spikelet number and days to ear emergence under both the normal (r = +0.74**) and 18‐hour photoperiod (r = +0.67**). Wide differences in spikelet number between wheats of closely similar developmental patterns indicated the likely presence of a significant genetic component of spikelet number determination in wheat.

It is postulated that in the absence of both photoperiod limitations and the need for vernalization, growth temperatures could differentially influence developmental rate among spring wheat genotypes.
Deicing Salt Movement and its Effects on Soil Parameters and Vegetation1
Authors: Buzio C. A. , Burt G. W. , Foss J. E.
Published: July 2010

Salt damage to the environment occurs in restricted areas in humid regions as a result of factors such as industrial waste, sea water, and deicing salt. A study was conducted, therefore, to determine the distribution of salt leached from a deicing salt pile, and its effects on soil parameters (pH, Mg, P, and K) and plant successional changes in a hardwood forest area. Lateral movement and leaching of chloride was studied as it occurred in an adjacent slope by sampling the soil (Sunnyside Sandy Loam; Typic Hapludult) to a depth of 76 cm at 17 sites. The soil samples collected from the field were then analyzed for salt content by using the conductivity bridge. Lateral movement (of chloride) was extensive with subsequent leaching to a depth greater than 76 cm. Of the measured soil parameters, only K was found to be correlated with NaCI concentration. Within 3 years of the establishment of the salt stockpile, all the trees in the sampled area were dead. Out of 29 plant species found to have invaded the sites with less than 5,000 ppm of NaCI, only 10 were found in sites with concentrations greater than 15,000 ppm. Recommendations to be considered when establishing a deicing salt pile are presented.
Responses of Cowpeas to Applications of P and Fe in Calcareous Soils1
Authors: Kashirad A. , Bassiri A. , Kheradnam M.
Published: July 2010

The relationship between P and Fe in nutrition and development of plants have been studied in detail for some crop species. However, there is no such report available on cowpeas (Vigna sinensis L.). This study was initiated to investigate the effects of P and Fe on growth and mineral contents of cowpeas in two arid region soils.

Cowpeas were grown for 8 weeks in two soil types (Typic Xerofluvent and Xerollic Xerochrept) from two locations (Airport and Kooshkak, respectively) containing various levels of P (0, 50, 100, and 200 ppm) and Fe (0, 5, 10, and 20 ppm). Airport soil (loam) had high soluble salts, high exchangeable Na and low organic matter, N, Fe, Zn, and Mn as compared to Kooshkak soil (silty clay).

Symptoms of Fe deficiency developed only on plants growing in the Airport soil when no Fe was applied. With the application of Fe as little as 5 ppm, the symptoms were prevented. The dry matter yield of plants grown in the Airport soil was significantly lower than that grown in Kooshkak soil under all treatments. Best plant growth was obtained when 50 or 100 ppm P were added to each soil; however, no Fe was required in the Kooshkak soil while 20 ppm Fe were needed in Airport soil for optimum growth.

The mineral contents in the tops of plants grown in either soil type were affected differently with increased levels of applied P or Fe. Significant interactions were observed between P and Fe treatments for most of the characteristics measured.
Hessian Fly Control in Wheat by Suppression of Fall Generations with Carbofuran1
Authors: Nelson L. R. , Morrill Wendell L.
Published: July 2010

Seed and soil treatments of the systemic insecticide, carbofuran, were investigated to determine their feasibility for control of the fall generation of the Hessian fly (Mayetiola destructor Say) on wheat (Triticum aestivum L.): By controlling the fall fly population levels, the second generation would not be of economic importance, and seed treatment would be an effective control method. The experiment was conducted in the field at Plains, Ga. on a sandy loam soil (Rhodic Paleudults; clayey, kaolinitic, thermic) and at Griffin, Ga. on a Cecil sandy loam soil (Typic Hapludults; clayey, kaolinitic, thermic). The cultivar ‘Holley’ was subjected to three carbofuran treatments; a seed treatment of 4.15 g AI/kg of seed, a broadcast soil treatment of 4.5 kg AI/ha, and an untreated control. The Hessian fly was effectively controlled in wheat by suppression of the first fall generation by using carbofuran either as a seed treatment or as a broadcast spray treatment. Seed treatments were biologically active for the period during which the first fly generation developed (ca. 30 days), while soil treatments remained biologically active for several months.
Mg, Ca, and K Status of Silage Corn and Wheat at Periodic Stages of Growth in the Field1
Authors: Schwartz S. , Kafkafi U.
Published: July 2010

The aim of this study was to compare the Mg and Ca content of a winter forage — wheat (Triticum aestivum) with a summer forage — corn (Zea mays L.) on several levels of N, P, and K fertilization. Specifically, the effect of soil fertility level and growth stage of the plants on the Mg content of the plant was studied with its connection to potential hazard of grass tetany (hypomagnesemia). Knowing the intrinsic differences between species of forage and the trend in Mg content changes during the growing season might help in preventing grass tetany. In two separate years corn and wheat were grown on a permanent plots fertilization experiment at the Bet Dagan experimental farm, Israel. In this field, five levels of N and P and three levels of K are checked in a factorial design. In the corn experiment the factorial combination of three levels of N; 0, 200, and 400 kg N/ha; three levels of P; 0, 80, and 150 kg P/ha; and two levels of K; 0 and 310 kg K/ha; were selected for detailed study. Plant samples were taken every week. In the wheat experiment five levels of N; 0, 30, 60, 120, and 240 kg N/ha on three levels of P; 0, 16, and 64 Kg/ha, and K at 270 kg/ha were sampled every 2 weeks. The plant material was dried, weighed, and analyzed. Magnesium and Ca uptake by wheat were found to be highly correlated (r = 0.986 for Mg and r = 0.982 for Ca) with N uptake and relatively unaffected by P fertilization. The absolute amounts of Mg and Ca taken up per ha of crop produced were considerably higher in corn i.e., 33.0 kg Mg/ha and 53.9 kg Ca/ha, than in wheat, i.e., 13.8 kg Mg/ha and 22.5 kg Ca/ha, when averaged over all treatments, exclusive of Ko. The antagonistic K‐Mg effect was readily observed in corn. Thus, 64.3 kg Mg/ha taken up in the N200P160K0 treatment was reduced to 39.1 kg Mg/ha in the N200P160K310 plots at equal dry matter production. With the exception of one stage of growth in wheat 4 weeks after emergence, Mg concentrations were below 0.2%, a level considered critical in the prevention of hypomagnesemic disorders in grazing cattle and sheep. Lowest Mg concentrations in Wheat, i.e., 0.06% to 0.07%, were observed in February just prior to and in the early stages of heading, 2 to 4 weeks prior to maximum dry matter production. Because of its lower uptake of Mg and Ca, wheat silage should be supplemented by Mg additives to prevent hypomagnesemic disorders. Based on this study, it is recommended that special attention should be paid to add Mg salts to milking cows in the mid‐winter months when grass pastures are used.
Quantification of Growth Drought Tolerance and Avoidance of Blue Grama Seedlings1
Authors: Wilson A. M. , Sarles J. A.
Published: July 2010

Planting failures with blue grama [Bouteloua gracilis (HBK.) Lag.] prompted the investigation of relationships between physiological and morphological traits and seedling drought resistance. The objectives of this study were to quantify the tolerance and avoidance components of growth drought resistance, determine the conditions under which measurements should be made, and assess the variability among seedlings in characteristics that contribute to drought resistance. Blue grama seedlings were restricted to the seminal primary root, irrigated to maintain favorable soil moisture conditions, and retained in plant growth chambers at either a low or a high relative humidity. When leaf area had increased to the maximum that could be supported by water from the root, tiller water potential was determined for a quantification of growth drought tolerance; and total leaf diffusion resistance, water uptake, and green leaf‐blade area were determined for a quantification of growth drought avoidance. Growth drought tolerance, defined as the plant drought that is just sufficient to halt the increase of seedling leaf area, varied among seedlings from about −20 to −40 bars. Growth drought avoidance, defined as the difference between plant drought and the drought of the shoot environment, is related to total leaf diffusion resistance, maximum capacity for water uptake, and seedling leaf area. Estimates of total leaf diffusion resistance varied among seedlings from 6 to 23 sec cm−1 and maximum rates of water uptake varied from 1 to 8 g day−1. Differences among accessions in capacity for water uptake suggest that improvements might be made in a plant breeding program. Additional work is needed to determine whether drought tolerance and total leaf diffusion resistance are heritable traits. The concept of growth drought resistance is particularly useful because it can be quantified for individual seedlings.