bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Burning Forage production of ‘Coastal’ Bermudagrass at Varying Levels of Fertilization1
Authors: Morris H. D.
Published: July 2010

The effect of burning ‘Coastal’ bermudagrass (Cynodon dactylon (L.) Pers.) sod during the winter or early spring was determined at three levels of fertilization over a 3‐year period, 1964‐1966. Burning increased forage yields 1,140 kg/ha when a high level of fertilization was utilized. Forage yields were not increased by burning at lower levels of fertilization. The beneficial effect of burning was attained each year at the second clipping (July) and was not a result of earlier forage production.

Burning provided more effective early weed control than mowing or herbicide treatments applied April 15. Burning on January 1 was not as effective for weed control as later burning. Burning April 1 provided maximum weed control and left the soil without vegetative cover for a minimum period of time. Soil temperatures on the burned plots averaged 1.7 C higher than those on the unburned plots during April and May. Burning had no significant effect on soil nitrogen content during the 3‐year experimental period.
Competition among Four Sorghum Types as Measured by Silage Yields and other Characteristics1
Authors: Johnson B. J.
Published: July 2010

The silage yields of four sorghum (Sorghum bicolor (L.) Moench) types were highest when bordered by the short type, and lowest when bordered by the tall type sorghum. Other agronomic characteristics of sorghums were not significantly influenced by border rows.
Excavation and Permanent Mounting of Corn Root Systems1
Authors: Moraghan J. T.
Published: July 2010

Permanent mounting of corn (Zea mays L.) root systems obtained by a pinboard technique can be achieved by placing the root system on a sheet of foamed polystyrene resin and spraying the roots and associated resin with an aerosol polyvinylchloride plastic. The polyvinylchloride forms a protective coating around the roots. The organic solvents present in the aerosol dissolve the surface of the adjacent resin and this, on drying, cements the root systems to the resin sheet.
Influence of Planting Rates and Mowing on Yield and Quality of Crimson Clover Seed1
Authors: Rampton H. H.
Published: July 2010

In a 3‐year experiment we studied the effects of difterent planting rates and of early spring mowing on yields and quality of crimson clover seed. High planting rates generally hastened plant development and maturity. In non‐mowed stands, the 5.6 and 9 kg/ha planting rates resulted, in the best seed yields. Mowing generally increased seed yields, germination, and hard seeds, and it decreased 1,000‐seed weight as compared with non‐mowing. Planting at 13.4 kg/ha plus mowing resulted in the most seed. ]Low planting rates may favor seed production because flowering and maturity are later. Effects of mowing conducive to high seed yields are: decreased lodging; delayed flowering and seed maturity until favorable pollinating and harvesting conditions prevail; and reduced bulk of plant material for threshing.
Relationship of Palmer Drought Variables to Yield of Winter Wheat
Authors: Brown Merle J. , Vanderlip R. L.
Published: July 2010

Multiple regression models were used to investigate the utility of Palmer drought variables in accounting for winter wheat yield. Yield data at seven western Kansas locations were correlated with monthly Palmer Drought Index and monthly moisture departure values. Yield records for the seven locations ranged from 23 years to 51 years.

Point yield data for four of the locations were correlated with weather and drought variables for points and areas for 1932‐1965. Use of the same period‐of‐yield records permitted the variables best correlated with winter wheat yields to be identified. Monthly precipitation, monthly Palmer Drought Index, monthly moisture departure, and estimated monthly subsoil moisture were the variables used.

Monthly point moisture departure, d, accounted for more of the variation in point winter wheat yield than did other drought and weather variables used, namely, point and area Palmer Drought Index, point and area estimated subsoil moisture, point and area precipitation, and area moisture departure. Except for point d values, there was little difference in point and area variables in accounting for variations in yield.

Monthly point moisture departure seemed to be superior to monthly point precipitation in explaining yield variations. Thus, that variable in lieu of, or in addition to, precipitation should be considered by researchers involved in correlating weather and crop yields.

The importance of available moisture at or near seeding time and in late winter and early spring was indicated by the results.
Effect of Corn Steep Liquor for Erosion Control and Vegetative Establishment on Highway Backslopes
Authors: Schmidt B. L. , Taylor G. S. , Miller R. W.
Published: July 2010

Various concentrations of a corn steep liquor slurry were compared with straw mulch for erosion control and vegetative establishment on highway backslope plots. Applications of 5 and 10% corn steep liquor slurry followed immediately with lime slurry formed a thin, stabilized surface layer that resisted initial erosion on backslope plots after seeding. However, plant growth, cover, and erosion control over a growing season were the greatest under straw mulch, with no significant differences noted from the various corn steep liquor treatments by the end of the season. Growth chamber studies showed corn steep liquor slurry concentrations of over 10% solids applied at 1.4 liters/m2 retarded emergence of tall fescue seedlings up to 1 week. Soil moisture evaporation losses in a greenhouse study were not significantly affected by various rates of corn steep liquor application, but were greatly decreased by straw mulch.
Relation of Hydrocyanic Acid Potential of Leaf Samples to That of Whole Plants of Sorghum1
Authors: Benson J. A. , Gray Elmer , Fribourg H. A.
Published: July 2010

The relationships between the hydrocyanic acid potential (HCN‐p) of leaves and whole plants were studied in ‘Piper’ sudangrass, Sorghum bicolor var. sudanense (L.) Moench, and ‘Suhi‐l’, sorghum‐sudangrass hybrid, S. bicolor ✕ S. bicolor var. sudanense, subjected to three cutting managements. The results were:

Leaf and whole plant samples from Suhi‐1 were usually higher in HCN‐p than samples from Piper at all harvest dates for the three cutting managements.

Plants cut at 10 cm when they reached the early bloom stage had significantly lower average HCN‐p than plants cut at 8 and 20 cm when they reached a height of 50 and 75 cm, respectively. Differences in average HCN‐p for the two latter cutting management were not signifant.

There were no significant differences among average HCN‐p of the whorl and the first and third leaves of Piper. For Suhi‐1, no significant difference was found between the average HCN‐p of the whorl and the first leaf. Both the whorl and the first leaf were significantly higher in HCN‐p than the third leaf.

There were no consistent trends in HCN‐p associated with successive harvest dates during the season.

Most of the simple correlation coefficients between HCN‐p of leaf samples and of whole plants were highly significant, indicating that leaf samples could be used to rank varieties for HCN‐p.

Ratios of leaf to whole plant HCN‐p were inconsistent; therefore, such samples are not suitable for estimating the total amount of HCN‐p of whole plants.
Permanent Pastures Improved with Sod‐seeding and Fertilization1
Authors: Decker A. M. , Retzer H. J. , Sarna M. L. , Kerr H. D.
Published: July 2010

‘Emerald’ crownvetch (Cornilla varia L.) and ‘Viking’ birdsfoot trefoil (Lotus corniculatus L.) were sod‐seeded into permanent bluegrass pastures. Three types of sod openers were evaluated along with the use of paraquat sprayed in a 15‐cm band over the seeded row to reduce competition from the existing sod. Forage production from these sod‐seeded treatments was compared with complete renovation and seeding to a mixture of orchardgrass (Dactylis glomerata L.), ladino clover (Trifolium repens L.) and red clover (Trifolium pratense L.) and to three rates of nitrogen topdressing on the undisturbed sward.

All of the treatments significantly increased forage yields with annual applications of N at 448 kg/ha being the highest. However, such a practice is not economically practical at present. Sod‐seeding with crownvetch was as good as either complete renovation or 140 kg N/ha annually. Sod‐seeded trefoil was less productive but in the third year of the study it was higher yielding than complete renovation.

Based on dry matter yields, birdsfoot trefoil and crownvetch offer good possibilities for improving permanent pastures production at minimum cost. These legumes can be seeded and the pasture fertilized in one trip over the field. Crownvetch is especially well suited to this type of seeding because of its spreading growth habit.

The disk and disk‐spear openers were generally superior to the spear only. However, with crownvetch the spear plus paraquat was also satisfactory.
A Germination Inhibitor in the Seedcoat of Sericea (Lespedeza cuneata (Dumont) G. Don)1
Authors: Logan R. H. , Hoveland C. S. , Donnelly E. D.
Published: July 2010

The effects of seedcoats of high‐ and low‐tannin sericea lespedeza on seed germination were studied. Seedcoat water extracts of both high‐ and low‐tannin sericea lines reduced germination and radicle elongation of sericea seed. Removal of seedcoats Increased germination of both lines when germinated with water. Seedcoats of seed from high‐tannin plants inhibited germination to a greater extent than those from low‐tannin plants. A seedcoat inhibitor may be a factor in slow germination of sericea. The high seedcoat tannin content of both sericea lines shows that germination inhibition is caused by a substance other than tannin.
Modifications of Pfeifer's Bird‐Control Apparatus1
Authors: Rosenau R. C. , Worstell R. V.
Published: July 2010

Pfeifer's bird‐control apparatus was modified and tested in 1967. Several safety feasures were incorporated. Also, an industrial timer was added as an interrupter to break the circuit from a high voltage transformer at regular, short intervals providing the arcing and snapping needed in a dry climate.
Kernel Opacity during Development and Moisture Content within Maize Ears Segregating for Opaque‐2 and Floury‐21
Authors: Paez A. V. , Helm J. L. , Zuber M. S.
Published: July 2010

Two lines each heterozygous for the genes opaque‐2 and floury‐2 were examined for segregation at 5‐day intervals, starting at 20 days after pollination until the 40th day. Identification of opaque‐2 and floury‐2 endosperm mutant classes by light transmission over a frosted glass was possible 25 days after pollination. Stages of kernel development and moisture content were factors found to be associated with identification of the two mutant classes.

Ears sergregating for these two mutants of several breeding lines showed differences in moisture content and kernel weight at post‐physiological maturity. Mutant classes had a significantly greater moisture content and lower average kernel weight at harvest.
Estimate of Optimum Plot Size for Cotton Yield Trials1
Authors: Kuehl R. O. , Kittock D. L.
Published: July 2010

We used data from 55 variety trials, four cultural experiments, and a uniformity trial of cotton, Gossypium hirsutum L. (Upland) and G. barbadense L. (Pima), to estimate soil heterogeneity and optimum plot size. Estimates of soil heterogeneity varied primarily with trial location. Optimum plot size was estimated from variety yield trials to be 53 m of total row length, and from a single uniformity trial to be 9 m. Shape of plot has little effect on plot variability.
Leaf Area Development, Light Interception, and the Growth of Canning Peas (Pisum sativum L.)1
Authors: Eastin John A. , Gritton Earl T.
Published: July 2010

Determinations of LAI3, CGR, LA/LW, LA/W, canopy height, and light attenuation were made for two canning pea cultivars in all possible combinations of three row spacings and three plant populations at several growth stages. The leaf area values and canopy heights, when considered in relation to models for simulating photosynthesis in plant communities, indicated that the development of increased LAI in conjunction with changes in leaf orientation and distribution and maintenance of maximum canopy height should be objectives in pea improvement programs. LA/W changes and their relationship to LAI and CGR provide evidence that growth had a positive effect on photosynthetic activity. LA/LW varied as a function of population, growth stage, and cultivar.
Effect of Light, Culture Solution, and Growth Period on Growth and Chemical Composition of Hydroponically Produced Oat Seedlings1
Authors: Trubey C. R. , Rhykerd C. L. , Noller C. H. , Ford D. R. , George J. R.
Published: July 2010

Oats were grown to evaluate the effect of light, culture solution and growth period on the growth and chemical composition of the young seedlings when grown in a hydroponic unit. The treatments consisted of light and dark, culture solution with and without nutrient elements and 3‐ and 6‐day growth periods.

Seedlings receiving light were significantly lower in fresh weight, crude protein and water soluble carbohydrates but considerably higher in beta‐carotene. Light did not affect dry matter or ash content over the relatively short growth periods. The addition of nutrient elements to the culture solution did not affect fresh weight, dry matter, crude protein, beta‐carotene or ash content but decreased the water soluble carbohydrate content. Growing the oat seedlings for 6 days resulted in higher fresh weight, soluble carbohydrates, beta‐carotene, and ash contents as compared to the seedlings of the 3‐day growth period. Length of growth period did not affect crude protein content but a dry matter decrease was observed for the 6‐day growth period.
Measurement of Drought Resistance in Corn1
Authors: Kilen T. C. , Andrew R. H.
Published: July 2010

Twelve dent and sweet corn lines exhibiting a range of phenotypic response to field drought were exposed to 1) a heat and atmospheric‐drought test of seedlings, 2) a test for chlorophyll stability of leaf tissue, and 3) conduction inhibition test of excised leaves. At two locations during 2 years in the field, lines were rated for leaf firing and measured for leaf blade area, tiller number, plant height, leaf number, stomatal number, and stem vascular bundle number. Results were positively and highly correlated among the three objective tests and for each test with leaf firing in the field. Plant height, but not other morphological measurements, was negatively and significantly correlated with test results and with leaf firing in the field.
Winter Survival and Spring Forage Yield of Winter Rye Varieties in Subarctic Alaska as Influenced by Date of Planting1
Authors: Klebesadel L. J.
Published: July 2010

Three dates of planting during late summer were compared in four successive field tests for effects on winter survival and on subsequent spring forage yields of several varieties of winter rye (Secale cereale L.) near Palmer in south‐central Alaska.

Amount of seedling growth achieved before termination of the growing season differed among years and was related to September temperatures. When winterkill was moderate to severe, survival of seedlings was better with planting 16 to 23 Aug. than earlier (9 to 12 Aug.) or later (27 Aug. to 8 Sept.). Earliest dates of planting, however, always resulted in earliest forage growth and highest yields the following spring. Yields were progressively smaller with successively later dates of planting.

In one test, only very winterhardy varieties were included and all survived the relatively mild winter without apparent injury. In the other three tests, winter stress resulted in disparate survival of rye cultivars. Varieties that grew most rapidly as seedlings sustained greatest winterkill. ‘Antelope,’ ‘Caribou,’ ‘Emerald,’ ‘Pierre,’ and ‘Sitnikoff’ were superior to ‘Elk,’ ‘Sangaste,’ and ‘Toivo’ in winter survival and, hence, in subsequent forage yield. Crude protein content of harvested forage was consistently high (20 to 26%) and was not influenced by varieties or planting dates.
Chemical Composition and Yield of Oats and Peas Separated from a Forage Mixture at Successive Stages of Growth1
Authors: Klebesadel L. J.
Published: July 2010

An oat‐pea (Arena sativa L.‐Pisum arvense L.) forage mixture was sampled at nine successive stages of growth during 3 consecutive crop years. Samples were separated into oat and pea components for chemical analyses and yield determinations. Percent dry matter in both crops and nitrogen‐free extract (N.F.E.) in oats increased during the growing season. Percent N.F.E. in peas, Ca in oats, and fat, Mg, and P in both oats and peas remained relatively constant during the sampling period. Percent crude fiber increased in both crops until oats were in the early milk stage and peas had 3 to 4 pods per plant and then declined in both crops. Percent ash and K in both crops and percent Ca in peas declined throughout the sampling period.

Percent crude protein decreased rapidly in both crops during the first two sampling intervals, then declined slowly in oats, and increased slightly in peas during subsequent growth.

Oats were higher than peas in percent dry matter, fiber, ash, and K. Levels of N.F.E., fat, and P were quite similar in the two crops, except that oats were lower than peas in N.F.E. during the first two samplings. Peas were higher than oats in percent protein, Ca, and Mg, except with the first two samplings when oats surpassed peas in percent protein.

Rate of dry‐matter accumulation was higher for oats during the first half of the sampling period but higher for peas during the last half. Per‐hectare yields of dry matter and of the various chemical constituents at conventional harvest stage revealed that oats and peas were complementary in composition. Oats surpassed peas in per‐hectare yields of dry matter, fiber, ash, N.F.E., and K. Peas, however, contributed most of the protein, Ca, and Mg. Oats and peas were about equal in yield of fat and P.
Use of Minimum Tillage and Herbicide for Establishing Legumes in Kentucky Bluegrass (Poa pratensis L.) Swards1
Authors: Taylor T. H. , Smith E. M. , Templeton W. C.
Published: July 2010

Factorial experiments were conducted for three successive years with plantings of alfalfa (Medicago sativa L.) made in spring, mid‐and late summer of each year. White clover (Trifolium repens L.) was sown only in spring. Tillage levels were none and strips tilled to a depth of 1.9 cm with widths of 0.6, 1.9 and 5.7 cm. Herbicide levels were none and paraquat, l:l‐dimethyl‐4, 4'dipyridylium dichloride, applied at 1.11 kg a.i./ha in bands of 5.1 and 10.2 cm over the seeded rows. Seeds were placed either on or below the soil surface. Spring plantings were most successful, late summer ones were intermediate, and those made in mid‐summer were poorest. Placing the seed 1.2 (alfalfa) or 0.6 cm (clover) below the soil surface was found to be the most consistent controllable factor contributing to successful establishment. Stands were equal or superior on the minimumtilled plots i.e., strips 0.6 cm wide and 1.9 cm deep, to those of other treatments. Paraquat banded over the seeded row enhanced legume stands only when grass stands were dense and growth was rapid. Based on success with minimum tillage, a prototype field machine was designed and constructed to till, seed, cultipack, and apply herbicide in one pass over the land.
Effects of Soil and Crop Management Practices on the Removal of Strontium‐90 by Plant Uptake, Leaching, Runoff and Erosion1
Authors: Haghiri F.
Published: July 2010

Long‐term field investigations are being conducted to study the effect of management practices on the removal of 90Sr by runoff, leaching, erosion and plant uptake. The management practices consist of one crop rotation with high and low rates of lime, permanent grass, continuous corn, and gravel mulch with no vegetation. Over a 5‐year period, the 90Sr content of the soil in a 0‐10‐cm depth decreased in all cropping systems. The percent 90Sr loss by runoff water and sediment was negatively correlated with time while the percent 90Sr in the leachate water increased with time. The percent 90Sr removal by runoff and leachate water was maximum under gravel mulch and minimum under grass treatments. Sod crops were more effective in minimizing the 90Sr loss in runoff and leachate water than cultivated crops. High Ca accumulating crops such as alfalfa removed more 90Sr than low accumulators such as corn. High rates of lime reduced the 90Sr uptake by crops and the removal by leachate water.
Collegiate Soils Contests, a Teaching Aid1
Authors: Jansen I. J. , Olson G. W. , Milford M. H.
Published: July 2010

Interest and participation in soils contests are growing steadily. Preparation for and participation in these contests are educational experiences quite unlike those acquired in formal classes. Participants in regional and national contests have the opportunity to broaden their knowledge by studying soils and landforms in regions unlike their own. The extracurricular nature of the contests and the competition among students and between teams gives participants the incentive to study soils with enthusiasm. The contests provide the setting for students and professors from schools in different parts of the country to exchange views and become better acquainted. In an attempt to evaluate the program, we sent questionnaires to individuals who had participated in past years, either as coaches or as team members. Respondents strongly support the program as an effective teaching device.
Effect of Puncturing Mature Endosperm on Corn Germination1
Authors: Helm J. L. , Zuber M. S.
Published: July 2010

A mechanical probe was used to puncture mature corn (Zea mays L.) kernels. After puncture the kernels were germinated at near optimum conditions. Kernels punctured at 7% moisture had better than 80% germination, while kernels punctured at 28% moisture had over 90% germination. These results indicate that after corn endosperm is punctured, to measure its physical properties, kernels can be satisfactorily germinated. This will allow segregating populations to be tested, and progenies can be grown from selected kernels.
Evapotranspiration and Water Stress of Barley with Increased Nitrogen1
Authors: Luebs R. E. , Laag A. E.
Published: July 2010

Nitrogen, equivalent to rates of 45 and 90 kg/ha, applied at emergence, increased the leaf area index of barley 44 and 109%, respectively, before stem elongation. for an 18‐day period before and during tillering, evapotranspiration was 14 and 43% higher with the 45‐ and 90‐kg rates, respectively. During a subsequent 26‐day dry period, available soil water was depleted first at the highest N level. Relative turgidity of barley leaves at the end of the dry period (2 weeks before heading) was 84, 65, and 52% for the 0‐, 45‐, and 90‐kg N rates, respectively. At the high N rate, the number of barley heads per unit land area was reduced 44% and the number of kernels per head, 40%. As a result, barley grain yield was decreased 1,470 kg/ha. In contrast, a yield increase of 450 kg/ha was obtained with the 45‐kg rate of N. These results illutrate how a moderately high rate of N, applied to N‐deficient soil with limited water, can result in severe water stress at a critical growth period and depress grain yield.
Effect of Particle Size on Long‐Term Availability of Sulfur on Annual‐Type Grasslands1
Authors: Jones M. B. , Ruckman J. E.
Published: July 2010

Elemental sulfur and gypsum were applied to separate plots in a subclover (Trifolium subterraneum L.) ‐grass pasture at 45 or 448 kg/ha. Diameter of the S particles was < 0.15 mm, 0.25‐0.29 mm, 0.30‐0.59 mm, or 0.84–2.00 mm. Forage yields, changes in botanical composition, and S uptake were determined annually for 7 years after application. At the 448‐kg level, uptake of S from the smallest‐sized particles was highest during the first 2 years. Thereafter it decreased annually. Uptake of S from gypsum followed a similar pattern, but the decrease was more rapid. With the 0.25–0.29‐mm particles, uptake was less than from the smallest particles the first year, but the level remained relatively constant for 3 years, with only small decreases in subsequent years. Uptake of S from the 0.30–0.59‐mm particles was less than half that from the finest S the 1st year after application, but there was no decrease in uptake with time. Also, the uptake was about twice that from the largest‐sized particles throughout the period of the experiment. Where 45 kg S/ha was applied, relative amounts of S uptake from the various sized particles were similar to that with the 448‐kg application in the 1st year after application except that the amounts were much less. In subsequent years the increase in S uptake caused by application of the finest S decreased more rapidly than where the heavy rate was applied. Also the cumulative S uptake from coarse S fractions did not exceed uptake from the finest S as it did where the heavier S was applied.

Where 45 kg S/ha was applied increased forage production was closely related to S availability, particle size, and S uptake.

Increases in forage production with the application of 448 kg S did not follow the same pattern as S uptake with regard to particle size. Yield increases were least where < 0.15‐mm particles were used. This probably was caused by side effects, since soil pH was reduced by the heavy application of the finest S.
A Constant‐Temperature Setting Device for Cam‐Actuated Temperature Programmers
Authors: George Donald W.
Published: July 2010

Described and illustrated is an attachment which can substitute for the cam on cam‐actuated programmers. By providing an index point it permits precise preselection of a desired control level. A nut‐and‐threaded‐shaft adjuster allows for small changes in setting.
Winter and Summer Soybean Growth in Southern California1
Authors: Abel G. H.
Published: July 2010

Soybean growth under mildly low temperatures and short photoperiods from mid‐December and mid‐February plantings was compared to the normal summer growth from May to June plantings. Seed germination time increased and plant height decreased, depending mainly on the temperature. Low temperatures delayed flowering approximately 30 days beyond the established 25‐day limit of flowering of all varieties grown under optimum temperatures and short photoperiods. Extending the photoperiod above the critical for flowering with artificial light delayed flowering time a few days and essentially doubled the per‐hectare yield to 1,260 kg of dry stalk and 460 kg of seed from the December planting. Extending the photoperiod for the February planting decreased seed yield and seed quality because of competition with the reinducted vegetative stage resulting from the normal 14‐hr photoperiods that occurred later in the growth cycle. These yields from winter plantings compare to 7,907 kg/ha of dry stalk and 2,347 kg/ha of seed from normal summer growth.
Influence of Water Temperature on Submersion Tolerance of Four Grasses1
Authors: Beard James B. , Martin David P.
Published: July 2010

Mature sods of ‘Toronto’ creeping bentgrass (Agrostis palustris Huds.), ‘Merion’ Kentucky bluegrass (Poa pratensis L.), annual bluegrass (P. annua L.) and ‘Pennlawn’ red rescue (Festuca rubra L.) were submerged in constant temperature water tanks at water temperatures of 10, 20, and 30 C. Three replications of each species were removed at designated intervals, drained, and placed in a greenhouse maintained at 20 C for evaluation of survival. Differentials in turfgrass species tolerance to extended periods of submersion were evident with Toronto creeping bentgrass showing superior tolerance, Merion Kentucky bluegrass and annual bluegrass ranking intermediate, and Pennlawn red fescue being quite intolerant. The duration of submersion tolerance was inversely proportional to the water temperature. Symptoms of injury at 30 C were visible on the intolerant species at the time of removal from the water tank and after 3 to 4 days on the tolerant species. There was a rapid loss of chlorophyll followed by general plant deterioration. Death occurred initially at the leaf tips of older leaves followed by a brownish discoloration of the leaf sheath.
Phosphorus Concentrations in Wheat Leaves in Relation to Phosphorus Toxicity1
Authors: Bhatti A. S. , Loneragan J. F.
Published: July 2010

The relationship between P concentration and the development of P toxicity symptcms in leaves was followed in young wheat plants growing on a siliceous sand at two levels of CaH4(32PO4)2 and of NH4NO3

32P accumulated in the terminal region of the first leaves prior to the appearance of necrotic symptoms. When symptoms developed they coincided closely with regions of 32P accumulation. NH4NO3 slowed down the rate of 33P accumulation in leaf tips and alleviated P toxicity symptoms.

P concentrations in and near necrotic areas of leaf tips ranged from 4 to 5% dry weight and most of this could be expected to be present largely (80% or more) as inorganic orthophosphate salts. Phosphate concentration in the cell sap could reach values of 200 mM with an osmotic pressure of about 10 atmospheres. It is suggested that under certain conditions this high phosphate concentration might disturb the water relations of the leaf cells, thus causing the observed injury.
Phytotoxicity of Water Extracts of Fruit, Stems, and Roots of the Tomato Plant and a Technique for Its Determination1
Authors: Simmons R. Walter , Axley John H.
Published: July 2010

A modified “rag doll” test was used to demonstrate that the entire tomato plant does not exhibit uniform toxicity to wheat seedlings. The major toxicity resides in the fruit as opposed to vines and roots.

The “rag doll” test for seed germination was modified to become a biological toxin assay test. It had a coeffi. dent of variation of 37.9% and 35.9% for roots and shoots which is comparable to 79.8% and 64.4% for the petri dish test.
Differences in Annual Clover Responses to Phosphorus and Sulfur1
Authors: Jones M. B. , Lawler P. W. , Ruckman J. E.
Published: July 2010

Many new varieties of winter annual legumes are now available for pastures in Mediterranean type climates. Since little work has been reported comparing the relative responses of these legumes to fertilization, 10 varieties of subclover, 6 of rose clover, 3 annual Medicagos, and 2 other annual clovers were grown in the greenhouse on a soil known to be deficient in P and S. There were four levels of P with S applied. The nil and highest P levels were repeated without S.

Yield differences between varieties and species were small where no P or S was applied. Responses to S alone were generally not significant, but responses to P only and P plus S varied significantly. Differences in response to P and S fertilization were as great among varieties of a given species as between species.

Highest yielding clover varieties tended to have lowest percentages of P and S. Differences in P and S uptake by the clover varieties were significant; however, uptake responses to fertilization tended to be relatively smaller than yield response differences, indicating that some varieties utilized absorbed nutrients more efficiently than others.

Response to fertilization apparently must be considered on a varietal basis rather than generalizing about species.
Crownvetch Seedling Growth on an Acid Soil as Influenced by Soil Preparation and Lime Placement1
Authors: Faix J. J. , Elkins D. M. , Jones J. H.
Published: July 2010

The experiment reported here was conducted to compare. the effect of disturbed and undisturbed soil and of lime placement under both soil conditions on seedling growth of crownvetch. The results are applicable to crownvetch establishment for roadbank stabilization. Crownvetch seedlings were grown from seed on disturbed and undisturbed Wartrace silty clay loam soil core samples (pH 4.6) taken from a simulated roadcut. Lime at a rate of 13.45 metric tons/ha was added to the top 0.5 cm of undisturbed core samples of bulk density 1.494, or mixed throughout disturbed and screened soil of bulk density 1.267.

Disturbed soil without lime, disturbed soil with lime mixed throughout, or disturbed soil with surface‐applied lime resulted in increased top and root growth over that in undisturbed soil. Top growth was significantly increased when lime was mixed throughout the disturbed core sample over that when lhne was added at the surface of the disturbed soil. There was no difference in root growth between these two treatments, but both were significantly higher than the other treatments. Disturbed soil without lime gave as much growth as when lime was surface‐applied on undisturbed cores, but there was an absence of nodules on all treatments where lime was not applied.
Effect of P, CaCO3 and CaSiO3 Fertilization upon Incidence of Corn Smut1
Authors: Tamimi Yusuf N. , Hunter James E.
Published: July 2010

Incidence of corn smut was investigated in two fertilizer (5 ✕ 5 factorial) experiments on P ✕ CaCO3 and P ✕ CaSiO3. Phosphorus rates were 0, 84, 168, 336, and 672 kg/ha; CaCO3 and CaSiO3 rates were 0, 6.72, 13.44, 26.88, and 53.76 tons (metric)/ha. In both experiments, the effect of P on reduction of corn smut was statistically significant. Disease incidence was reduced from 12.1 and 13.1 to 7.4 and 5.8% with application of 84 kg P/ha in the P ✕ CaCO3 and the P ✕ CaSiO3 experiments, respectively. Further increases in rate of P did not significantly reduce incidence of smut below that of the 84 kg P/ha. Rates of CaCO3 or CaSiO3 did not significantly affect the incidence of corn smut, yet percent infection in the P ✕ CaSiO3 treatments was significantly lower than in the P ✕ CaCO3 treatments (P < .08). There was no significant effect of the P ✕ CaCO3 or P ✕ CaSiO3 interaction on incidence of smut. Soil pH, which ranged from 5.12 to 6.84, was also found to have no significant effect on infection.
Viability of Kentucky Bluegrass Pollen (Poa pratensis L. ‘Newport’) as Influenced by Collection Time and Temperature1
Authors: Teare I. D. , Maun M. Anwar , Canode C. L.
Published: July 2010

Attempting to determine reasons for extreme variability in germination of Kentucky bluegrass pollen, we studied temperature and time effects, harvesting panicles from a seed field at 8:00 A.M., subjecting them to temperatures ranging from 21 C to 49 C, collecting pollen at hourly intervals for germination on agar medium and subsequent microscopic examination. Pollen viability decreased with increased exposure time and with higher temperature.

The average germination of pollen collected at 8:00 A.M. was approximately 50%, so we collected pollen in the field at half hour intervals from 6:00 to 8:00 A.M. and at hourly intervals thereafter until 4:00 P.M. Germination of pollen exceeded 80% from 6:00 to 7:30 A.M., but declined to 50% by 8:00 A.M. and to less than 2% by 9:00 A.M. Pollen collected each hour from 11:00 A.M. to 4:00 P.M. would not germinate.
A Tractor Mounted Unit for Harvesting Potatoes in Experimental Plots1
Authors: Christenson D. R. , White R. P.
Published: July 2010

A transportable unit for harvesting potatoes in experimental plots was developed by adapting a single row, power‐take‐off potato digger to a “three‐point” hydraulic tractor hitch. Digging depth was controlled by using a double acting hydraulic cylinder as the top link in combination with the lifting arms of the hitch. With the unit potatoes may be harvested from small plot areas without disturbing adjacent areas.
Exchangeable Aluminum Levels in Two Soils as Related to Lime Treatment and Growth of Six Crop Species1
Authors: Hutchinson F. E. , Hunter A. S.
Published: July 2010

Fifty soil samples were collected from the 12.7 to 15.8‐cm and the 43.2 to 48.3‐cmzones in five randomly selected selected sites for each of two acid glacial till soils to measure the relationship of pH and exchangeable AI. Alfalfa, alsike clover, orchardgrass, timothy, oats and barley were grown at three lime rates on one site of each soil which contained a high level of exchangeable A1 to determine the effects of varying pH and AI on crop yield. The Caribou and Thorndike soils contained an average of 255 and 346 kg/ha of exchangeable AI, respectively, at the 12.7 to 15.8‐cm depth, whereas the levels at 43.2 to 48.3‐cm were 152 and 347. There was significantly less A1 in the subsoil than in the topsoil of the Caribou. When limed rates of 0, 1,469 and 2,938 kg/ha for the Caribou and 0, 2,203 and 4,406 kg/ha for Thorndike soil, the average pH values were 5.03, 5.79 and 6.15, and 5.23, 6.08 and 6.46, respectively. Comparable exchangeable Al values were 196, 33 and 11, and 138, 21 and 19 kg/ha. Dry matter production of alfalfa, alsike clover and barley was significantly less when grown at AI levels greater than 100 kg/ha, whereas dry matter yields of oats, orchardgrass and timothy were uneffected at the above levels of A1. Grain yield of barley was reduced at the highest level of AI in one of the soils.
Germination of Cultivars of Trifolium subterraneum L. in Relation to Matric Potential1
Authors: Young James A. , Evans Raymond A. , Kay Burgess L.
Published: July 2010

The germination of 11 cultivars of subclover (Trifolium subterraneum L.) in relation to matric potential was dependent on the texture of the soil substrate. Germination terminated or was virtually zero at minus 6, 8, and 12 bars, respectively, on sand, loam, and clay substrates. Germination on soil beds in the greenhouse was dependent on substrate texture and the amount of seed coverage. On sand beds where the matric potential was high, hydraulic conductivity between the sand grains and the seeds on the soil surface was apparently so low as to impede germination. In all tests in which germination was more than minimal, variability among the cultivars was marked.
A Mechanical Node Harvester for Soybeans1
Authors: Clark R. C. , Fehr W. R. , Empig L. T.
Published: July 2010

We developed a mechanical node harvester for sampling bulk populations of soybeans (Glycine max (L.) Merrill). The node harvester consists of a metal box mounted on the cutter bar of a Scythette. A population is sampled by discarding the top half of the plants, then cutting and collecting one node from each plant with the node harvester.

The efficiency of the node harvester as a means of generation advance was compared with single‐seed descent, restricted cross‐bulk, maturity‐group bulk, and cross‐bulk. The methods were used to sample four varietal blends whose components could be distinguished by seed characteristics. The mechanical node harvester was not as accurate as single‐seed descent for equally sampling all plants of a population, but was five times faster than single‐seed descent. The principal advantages of the mechanical node harvester are that it (a) is as fast as the cross‐bulk method, (b) is more accurate for sampling than cross‐bulk, and (c) could be used as a mass‐selection device for improving the lodging resistance of a heterogeneous population.
Influence of Temperature on Seedling Growth and Carbohydrate Composition of Three Alfalfa Cultivars1
Authors: Ueno Masahiko , Smith Dale
Published: July 2010

Three cultivars of alfalfa (Medicago sativa L.), ‘Vernal,’ ‘Cody,’ and ‘Florida 66,’ were grown 35 days from seed in three temperature regimes: hot (H) 32C day/27C night, warm (W) 27/21C, and cool (C) 21/15C. Plant maturity was delayed as temperatures decreased. Shoot weights of heights and plant parts for each cultivar generally were greatest in the W regime, followed in order by the H and C regimes. Most of the significant differences among cultivars occurred in the C regime where Florida 66 was shorter in shoot height and produced less growth than Cody and Vernal.

Percentages of total nonstructural carbohydrates (TNC) in the plant parts were influenced more by temperature than percentages of structural tissue (ST). Weights of ST and TNC were closely related to dry matter yields, but temperature influenced the weights of ST more than those of TNC.
Effective Day Lengths for the Study of Photoperiod Sensitive Reactions in Plants1
Authors: Francis C. A.
Published: July 2010

The number of hours with a light intensity above the critical level for photoperiod sensitive reactions in plants is greater than the number of sunlight hours. In temperate latitudes, dark periods calculated from time of sunset to sunrise are nearly 1 hour longer than the effective dark period with an intensity less than 1 ft.‐c.; conversely, the effective photoperiod is longer by 1 hour. The length of the twilight period was used to calculate the number of “photoperiod effective” hours above critical intensities of 10, 5, 2, and 1 ft.‐c. (108, 54, 22, and 11 lux). These photoperiodic day lengths are presented for latitudes from 70° N to 60° S and all months of the year. Heavy cloud cover reduces the effective photoperiod, while scattered high clouds may reflect enough light from the sun below the horizon to lengthen the day slightly. These physical day lengths may be used to predict plant response for different planting dates in a given location when critical intensities of light and critical photoperiods which influence reactions in each crop species are known.
Soil Water and Soil Temperature Influences on Dryland Winter Wheat1
Authors: Black A. L.
Published: July 2010

Effects of wheat straw mulch on soil water and soil temperature in the 0‐ to 7.6‐cm soil layer and their subsequent influence of plant development and grain yields of winter wheat (Triticum aestivum L., ‘Winalta’) were evaluated over a 3‐year period. Mulch rates of 0, 1,680, and 3,360 kg/ha were applied randomly or in bands centered over or between wheat rows planted in 35‐, 70‐, and 90‐cm row spacings. Band applications of straw were applied at the same rates per unit area as that covered by randomly applied straw but in band widths of 18, 35, and 45 cm for the respective row spacings.

In a time sequence of correlations, number of tillers and number of adventitious roots were positively correlated with a moist soil‐degree day index (P=.01) based on May soil water and soil temperature measurements, number of adventitious roots was positively correlated with number of heads/ha (P=.01), and number of heads/ha was positively correlated with grain yield (P=.01). Numbers of adventitious roots, tillers, and heads and final grain yields were dependent upon the soil water and soil temperature of the 0‐ to 7.6‐cm soil layer during May. The intermediate straw mulch rate (1,680 kg/ha) applied randomly or in bands over the wheat row significantly increased the number of moist soil‐degree days and grain yields in 2 of 3 years compared to bare fallow or the high straw mulch rate (3,360 kg/ha).
Symap and Net Radiation in a Soybean Canopy1
Authors: Luxmoore R. J. , Millington R. J. , Peters D. B.
Published: July 2010

Spatially disposed net radiation data from a soybean canopy were mapped using an interpolation and mapping computer program called “Symap.” A large proportion of radiation was intercepted by the upper peripheral layer of leaves. The Symap program has application to other crop environment studies.
Effects of Nitrogen Rates and Plant Spacing on Sunflower Seed Yields and Other Characteristics1
Authors: Massey John H.
Published: July 2010

abstract

Field experiments were conducted to determine effects of nitrogen and plant spacing on sunflower (Helianthus annuus L.). Nitrogen rates were 0, 56, 112, and 168 kg/ ha, and plants were spaced 15, 30, and 46 cm apart within rows 1.1 m wide.

Nitrogen at 56 kg/ha increased seed yield, grams of seed per head, seed size, and head diameter 653 kg/ha, 17.7 g, 1.9 g/200, and 2.2 cm, respectively, as compared to nontreated plots. Plant height was increased 11 cm and stem diameter 4 mm by 56 kgN/ha. No further increases resulted from additional N. Nitrogen did not affect number of leaves per plant.

Seed yield decreased, but yield per head and head diameter increased with each 15‐cm increase in plant spacing. Seed were larger at 30‐ and 46‐ than at 15‐cm spacing. Spacing did not affect plant height or number of leaves, but stem diameter increased with wider spacing.

There was no significant interaction between nitrogen and plant spacing for any characteristic studied.
Evaluation of Cool Season Grass Species and Varieties Using In Vivo and In Vitro Techniques1
Authors: Wurster M. J. , Kamstra L. D. , Ross J. G.
Published: July 2010

Digestibility of the cool season grass species, smooth bromegrass (Bromus inermis Leyss), intermediate wheatgrass [Agropyron intermedium (Host) Beauv.] and the crested wheatgrass complex [Agropyron sibericum (Willd.) Beauv. and Agropyron desertorum (Fisch.) Shult.] was measured at heading and 2 weeks after by in vivo and in vitro techniques. In addition, plant fraction percentages and digestibilities were determined throughout the season for two varieties within each of the above species, ‘Manchar’ and ‘Sac’ bromegrass, ‘Greenar’ and ‘Oahe’ intermediate wheatgrass, and ‘P‐27’ Siberian wheatgrass and ‘Nordan’ crested wheatgrass. Both in vivo and in vitro criteria, as well as chemical analyses, indicated that intermediate wheatgrass was lower in digestibility than the other two species. Bromegrass and crested wheatgrass differed very little; bromegrass was slightly superior under in vivo test, while crested wheatgrass was slightly but significantly superior when in vitro techniques were used. A high correlation (r=0.89) was found between in vitro and in vivo dry matter digestibility.

At heading and 2 weeks after, in vitro dry matter digestibility indicated that Greenar was significantly superior to Oahe. No significant difference was found between the varieties of the other species. When entire plant and plant fractions were sampled over the growing season, Sac bromegrass was significantly superior to Manchar, Greenar intermediate wheatgrass to Oahe and Nordan crested wheatgrass to Siberian. These results indicate the possibility of selecting for more highly digestible stems and sheaths to produce a variety for utilization at the time of maximumd dry matter yield. For grazing purposes, however, selection at an early stage for whole plant digestibility would seem desirable.
Cutting Management Effects on Growth Rate and Dry Matter Digestibility of the Sorghum‐Sudangrass Cultivar Sudax SX‐111
Authors: Edwards Ned C. , Fribourg Henry A. , Montgomery M. J.
Published: July 2010

Relationships between growth rate and dry matter digestibility, as influenced by frequency of cutting and stage of growth, were examined for a sorghum‐sudangrass hybrid cultivar (Sorghum bicolor (L.) Moench ✕ Sorghum sudanense (Piper) Stapf. ‘Sudax SX‐11’). Growth rates were obtained by harvesting intact plants and measuring yield components at weekly intervals. Digestible dry matter (DDM) was estimated by measuring the dry matter disappearance using the nylon‐bag technique.

The seasonal distribution and amounts of dry matter and of DDM were altered by variations in cutting management (early‐boot vs. 75‐cm growth) and environmental conditions. DDM of entire plants was proportional to percent leaves and inversely related to percent stems. DDM of stems decreased about three times more and faster than the DDM of leaves during a 14‐week period. DDM of entire plants decreased from 90% when plants were 30 cm high to less than 60% when plants were 250 cm tall, and remained relatively constant for 6 weeks after panicle emergence.