bluuebunny/crossref_metadata_2025_split huggingface dataset:
Yield Response of Upland Cotton (Gossypium hirsutum L.) to Several Spacing Arrangements1
Authors: Hawkins B. S. , Peacock H. A. 
Published: July 2010

AbstractA 3‐year study with Upland cotton (Gossypium hirsutum L.) was conducted at Experiment, Ga., to determine the effects of plants/hill, within‐row hill spacings, and plant populations on lint yield.Highest yields were obtained when the populations were within a range of 96,000 to 144,000 plants/ha. Below this population range yield decreased sharply; above this population range yield was reduced but the rate of decline was more gradual than the decline in the low population range. The highest average yield (919 kg lint/ha) was obtained from five plants/hill spaced 40 cm apart (120,412 plants/ha). When all hill spacings were combined, the mean yield from five plants/hill (879 kg/ha) was significantly (P = .05) higher than yield from two plants/hill (812 kg/ha). Yield differences among hill populations of three, four, or five plants were not significant. When the plants/hill treatments were combined, yields from plants spaced 20 and 40 cm apart were significantly higher (P = .01) than yield from plants spaced 60 cm apart. The plants/hill ✕ hill spacings interaction was not significant.
Effects of Plant Population and Harvest Date on Stem Yield and Growth Components of Kenaf in Maryland1
Authors: Higgins J. J. , White G. A. 
Published: July 2010

AbstractKenaf is a potential new annual crop source of paper pulp. To minimize storage stockpiling of this new, bulky raw material, pulp processors may begin harvesting well before killing frosts and continue for several months beyond. Possible stem yield reductions with this extended harvesting system and the influence of plant populations on the reductions becomes of practical concern. The effects of four populations and five harvest dates on stem yields and other growth components on kenaf variety ‘Everglades 71’ were studied at Glenn Dale, Md., in 1966 and 1967. Populations of 99, 198, 297, and 395 thousand plants/ha did not affect stem yield or plant height in 1966 or yield in 1967. Basal stem diameters decreased as populations increased. There was a gradual loss of plants as harvesting was delayed. The greatest loss of about 25% was for the highest population. The best stem yields across the four populations were obtained from Oct. 4, 1966, (13.5 mt/ha) and Nov. 7, 1967, (11.7 mt/ha) harvests. These data indicate that populations of 200 to 300 thousand plants/ha and harvesting at about the time of killing frosts will result in the highest stem yields of kenaf under Maryland conditions.
Factors Influencing Freezing of Supercooled Water in Tender Plants1
Authors: Cary J. W. , Mayland H. F. 
Published: July 2010

AbstractSeedlings of beans (Phaseolus vulgaris), corn (Zea mays), and tomatoes (Lycopersicon esculentum) were grown in the greenhouse and then exposed to controlled freezing conditions in a growth chamber. Variables were adjusted to determine the influence of plant water potential, freezing time, and external dew formation on the seedlings' susceptibility to frost injury. Freezing, detected visually and by release of latent heat, progressed rapidly throughout plants with high water potential and was always lethal. Spreading of the ice phase was impeded in plants with low water potential. In this case, the freezing injury appeared as spots on the leaves which gradually enlarged to encompass the entire leaf as the exposure continued. In general, the plant water supercooled before freezing. Supercooled water within the plant appeared to be internally nucleated if the leaf temperature remained above th atmospheric dewpoint temperature. Under these conditions root temperature, plant water energy, and duration of the freezing period all influenced the stability of the supercooled water. On the other hand, external inoculation prevailed when the freezing temperatures were accompanied by condensation of water from the air and subsequent formation of ice crystals on the leaves. One important exception was noted when ice on corn seedling leaves failed to nucleate the supercooled internal plant water with a potential of −18 bars.
Perennial Irrigated Pastures. I. Plant, Soil Water, and Animal Responses Under Rotational and Continuous Grazing1
Authors: Raguse C. A. , Henderson D. W. , Hull J. L. 
Published: July 2010

AbstractContinuous grazing favored strawberry clover (Trifolium fragiferum L. ‘Salina’), and rotational grazing (5‐field; 1‐week grazing, 4‐week recovery) favored Ladino clover (T. repens L.) in a sward containing Ladino clover, ‘Salina’ strawberry clover, orchardgrass (Dactylis glomerata L), and perennial ryegrass (Lolium perenne L.). A 2‐field rotation (I‐week, I‐week) favored strawberry clover but had less influence on botanical composition than either 5‐field rotation or continuous grazing. Continuous grazing resulted in a higher percentage of plant cover than did 5‐field rotational grazing. Yields of beef per unit area were similar under the three systems. Water infiltration increased progressively during the 4 years of the experiment, and final infiltration rates were 2 to 3 cm/hr in both continuous and rotationally grazed pastures.
Co‐Grazing of Sheep and Cattle on an Orchardgrass Sward
Authors: Reynolds Paul J. , Bond James , Carlson G. E. , Jackson Charlie , Hart R. H. , Lindahl Ivan L. 
Published: July 2010

AbstractThe objective was to determine whether there is any advantage to co‐grazing, i.e., the grazing of cattle and sheep together, relative to grazing either species separately. The study was conducted over four successive grazing seasons on a highly fertilized sward that was a mixture of Ladino clover (Trifolium repens L.) and orchardgrass (Dactylis glomerata L.) the first season and nearly pure orchardgrass thereafter.Two apparent effects of co‐grazing were observed: First, an increase in rate of gain of sheep grazed with cattle at a ratio of five sheep per steer. This greater rate of gain, however, did not result in a greater liveweight gain/ha of cattle and sheep combined. Available forage was maintained at fixed levels, and the lack of any advantage in total gain/ha to co‐grazing at a ratio of 1 steer per 5 sheep is discussed in relation to similar experiments in which an advantage to co‐grazing was observed, but in which the effects of cattle:sheep ratio and available forage were confounded.Second, at one sheep per steed the animals were cograzed without affecting the rate of gain of the steers, but with an apparent increase in liveweight gain/ha relative to either cattle or to sheep grazed separately. This apparent effect of co‐grazing, however, was probably the result of a subtle increase in stocking rate that could have been brought about by either species independently of the other and, therefore, is not attributable to cograzing per se.
Corn Performance in Relation to Row Spacings, Populations, and Hybrids on Five Soils in Indiana1
Authors: Stivers R. K. , Griffith D. R. , Christmas E. P. 
Published: July 2010

AbstractThe purpose of this research was to determine whether narrow rows of corn (Zea mays L.) would yield more grain and dry matter than conventional 102−cm wide rows under a wide range of conditions. Eleven location‐year trials were conducted on five slightly acid soils at four widely scattetred locations in Indiana during 1966–1968. Three row widths: 51−, 76−, and 102−cm; two populations: 54,000 and 69,000 plants/ha; and three hybrids: one early, one full season, and one full season or late; were compared. Average grain yields were increased 7.3% with rows 51−cm wide, and 4.4% with rows 76−cm wide in comparison to rows 102−cm wide. More barren stalks contributed to the lower yields of the 102−cm rows under drouth stress conditions.Total aboveground dry matter yields on Chalmers silty clay loam soil were 5.0% higher with 51−cm rows and .5.4% higher with 76−cm rows than those of the 102−cm rows. The 69,000 plants/ha population produced 4.0% more dry matter than the 54,000 population on this Chalmers soil.Average grain yields of the 69.000 plants/ha population were 2.3% lower than those of the 54,000 population in the II location‐year trials.Full season corn hybrids generally produced higher yields of grain than either early or late hybrids in these trials. Some full and late, as well as early season, corn hybrids had higher grain yields with narrow corn rows.
Nutritive Relationships in Low‐ and High‐tannin Sericea Lespedeza Under Grazing1
Authors: Donnelly E. D. , Anthony W. B. , Langford J. W. 
Published: July 2010

AbstractA study was made on low‐ and high‐tannin sericea lespedeza [Lespedeza cuneata (Dumont) G. Don] to obtain information, using grazing steers, on the relationship of tannin and digestible dry matter (DDM), digestibility of crude protein, daily dry‐matter intake, and daily DDM intake. Tannin, crude protein, DDM, digestibility of crude protein, daily dry‐matter intake, daily DDM intake, and fecal crude protein were determined. Crude protein percentage was the same for the two forages and remained relatively high throughout three grazing periods from May through mid‐September. However, crude protein and dry matter of low‐tannin sericea were more highly digested than that in high‐tannin sericea.
Retention Patterns and Effectiveness of Anhydrous Ammonia Applied with an Undercutting Blade1
Authors: Swart C. L. , Murphy L. S. , Swallow C. W. 
Published: July 2010

AbstractRetention of and distribution patterns of anhydrous ammonia applied with an undercutting blade were investigated on soils of varying cation exchange capacities (CEC). Rates of ammonia ranged from 56 to 224 kg N/ ha; spacings between points of ammonia release ranged from 15 to 102 cm. Application depths were 5 and 10 cm.Applying 224 kg N/ha on a silt loam soil resulted in no measurable loss at any depth or spacing. Shallow (5‐cm) applications resulted in some ammonia loss on a low CEC soil; 224 kg N/ha applied 10 cm deep also resulted in ammonia loss when dispersed with 102‐cm spacings. A 15‐cm spacing, however, reduced the loss to less than 1%. Soil texture and depth of application did not appreciably alter the distribution patterns but affected ammonia losses.Distinct distribution patterns resulted from each release‐point spacing. Ammonia distribution patterns were commonly oval around each release point. Lateral movement was directly proportional to application rate, while vertical movement was limited to less than 5 cm.A second phase of the study involved preplant field applications of ammonia for wheat (Triticum aestivum L.). Effects of N rate and spacing of release points on plant N absorption, wheat yield, test weight, and protein content of the grain were recorded for five Kansas locations.Plant N concentration correlated positively with soil inorganic N in samples collected 7 months after NH3 application. Variations in NH3 release‐point spacings produced marked differences in growth, particularly in the spring. The 15‐cm and 41‐cm release‐point spacings generally produced more uniform plant growth, which resulted in higher yields than the 102‐cm spacing; however, the differences were not significant at the 5% level.
Effect of Different Levels of Nitrogen and Phosphorus on Yield, Soil Properties, and Nutrients of Corn1
Authors: Shukla G. C. 
Published: July 2010

AbstractThe effect of five levels of N and three levels of P on yields, soil properties, and uptake of nutrients of corn (Zea mays L.) was studied at Central Agricultural Station (CAS), Central Horticultural Station (CHS), and Black Bush Polder (BBP) in Guyana. Corn yield showed a significant response up to 180 kg N/ha applied at CAS and CHS. At BBP the yield increase was nonsignificant. P gave a significant effect on yield in one season at CAS only.The changes in soil properties from the time of planting first crop to the harvesting of the second crop at CAS and CHS are described. Application of N had a residual effect on both the soils. The changes in P and K followed different patterns on two soils. After cropping, pH and exchangeable Ca and Mg increased in both the soils.Nitrogen rates significantly increased N and K and decreased P content of the leaves. P levels had a nonsignificant effect on the uptake of nutrients.
Effects of Trifluralin on Fertilizer Phosphorus Uptake Patterns by Cotton and Soybean Seedlings1
Authors: Cathey George W. , Sabbe Wayne E. 
Published: July 2010

AbstractTwo greenhouse experiments were conducted to study the effect of trifluralin (a, a, a, trifluoro ‐ 2, 6‐dinitro‐N, N‐dipropyl ‐ p‐ toluidine) on P uptake patterns by cotton (Gossypium hirsutum L.) and soybean [Glycine max (L.) Merr.] seedlings. Fertilizer P uptake from each of three soil zones was altered when the herbicide was present in the root substrate. The greatest alteration occurred when the herbicide was located in the center soil zone (5 to 10 cm). The uptake of P was decreased when the fertilizer and trifluralin were located in the same soil zone, whereas, in some cases a stimulation of P uptake from the fertilizer zone occurred when the herbicide was confined to a separate soil zone. The fertilizer P uptake was affected least when the herbicide was placed in the top soil zone (0 to 5 cm).
Prediction of Flowering Dates in Maize Based on Different Methods of Estimating Thermal Units1
Authors: Cross H. Z. , Zuber M. S. 
Published: July 2010

AbstractIn an attempt to find better ways of estimating relative maturity differences in corn (Zea mays L.), various thermal unit formulas were evaluated. Utilizing data from six plantings of corn over a 2 year period, 22 different methods of computing thermal units were tested for their ability to account for variation in flowering dates. Both hourly and daily temperature data were used in the equations. In general the daily measurements appeared to be approximately as accurate as the hourly measurements. The best equation for predicting flowering dates on the basis of thermal units utilized a base temperature of 10C (50F) and an optimum of 30C (86F). The excess temperature above 30C was subtracted to account for high temperature stress.
Emergence Force of Forage Seedlings1
Authors: Jensen E. H. , Frelich James R. , Gifford R. O. 
Published: July 2010

AbstractThe experiments were conducted to quantitatively determine the relative force exerted by germinating forage seedlings. Information obtained could be used for the selection of forage species most likely to emerge through soil crusts.An apparatus was used that employed a force transducer to measure the relative force exerted during seedling emergence. A continuous record of the vertical force was observed for each seedling. The resulting curve reflected the relative force a seedling exerted at a particular time of emergence after germination.The emergence force exerted by a seedling differed significantly among alfalfa (‘Medicago sativa’ L.), strawberry clover (Trifolium fragiferum L. ‘Salina’), alsike clover (Trifolium hybridium L.), and narrow‐leaf birdsfoot trefoil (Lotus tennis Wald. et. Kit.) and was positively correlated with seed weight. Alfalfa exhibited a significantly higher mean weekly emergence force, while narrowleaf birdsfoot trefoil seedlings exerted a significantly lower mean weekly emergence force than the other species tested. Curves generally indicate that force increased very rapidly for legumes 24 to 48 hours after transplanting with a gradual decrease thereafter. The magnitude of force exerted by tall wheatgrass (Agropyron elongatum Host) and alfalfa seedlings was not significantly decreased until —5.0 bars of osmotic potential (O.P.) was imposed. A decrease in O.P., however, significantly increased the time required to reach a maximum force by alfalfa but not by tall wheatgrass. Force curves of tall wheatgrass indicated that 5 to 6 days were required to reach a maximum force, compared to 1 to 2 days for legumes. Sodium adsorption ratios did not affect the emergence force of alfalfa seedlings.
Effect of Temperatures and Water Table Depth on the Growth of Creeping Bentgrass Roots1
Authors: Ralston D. S. , Daniel W. H. 
Published: July 2010

AbstractThe PURR‐WICK system, as developed at Purdue University in 1966, provides an impermeable underlay, plus possible retention of free water by outflow drainage control. What would be the effect in this system of sand texture, depth of water reserve, and temperature? ‘Penncross’ bentgrass (Agrostis palustris Huds.) was grown in columns of finer and coarser sand mixes with water tables maintained at depths of 11, 25, and 40 cm in constant temperature chambers of 15 and 30 C for 9 weeks.Temperature had the greatest effect. At 15 C root growth was slow initially but steadily maintained. At 30 C initial root growth was rapid but declined to little or no growth, so that total root length at 15 C was three times that for 30 C. Within each temperature the water table ✕ sand interaction was significant. Root growth was better in the coarser sand for the 11‐ and 25‐cm water tables and better in the finer sand for the 40‐cm treatment. The deepest root growth was found at 15 C in the finer sand mix with the water table at 40 cm. Where oxygen diffusion was favored by coarse texture, roots were still limited by higher temperature.
Selenium Accumulation in Astragalus Species
Authors: Davis A. M. 
Published: July 2010

AbstractSome Astragalus species are known to be Se accumulators and are toxic to grazing animals. The Western Regional Plant Introduction Station, Pullman, Wash., had 108 accessions representing 49 species of Astragalus, mostly of non‐North American origin, available for this study. The Se accumulation characteristics of these had not been determined and therefore their potential as forage in areas of seleniferous soil was open to question.Plants were greenhouse grown in soil containing 18 ppm Se. The forage was dried and analyzed for total Se by AOAC methods.Selenium content varied from a high of 213 ppm in Astragalus tephrosoides Boiss. to a low of no detectable Se in 45 accessions. Sixty accessions, representing 26 species, accumulated 5 ppm Se or more and could be poisonous to grazing animals.
Bird Resistance in Diverse Germplasm of Sorghum1
Authors: McMillian W. W. , Wiseman B. R. , Burns R. E. , Harris H. B. , Greene G. L. 
Published: July 2010

AbstractThis study was conducted to examine the relative amount of bird resistance present in a broad spectrum of available sorghum [Sorghum bicolor (L.) Moench] since bird resistance is highly desirable for inclusion into plant breeding programs. Ratings were taken on damage inflicted by natural populations of birds and on several plant characters, including tannin content of the seed, color of the seed, and plant height. The bird damage done to 142 domestic and exotic lines of sorghum revealed the presence of germplasm imparting resistance to birds: SPI 35038 had a low damage rating (2.5); lines SA 370 and Colby had a high damage rating (9.0). Some commercially available sorghum hybrids also appeared to have resistance. The amount of tannin in the sorghum seed was negatively associated with bird damage, as were seed color and plant height, although to a lesser extent. The amount of tannin and seed color showed a positive correlation. Nevertheless, several sorghum lines appeared to be resistant that contained a relatively low amount of tannin.
Effect of N Fertilization on Dry Matter Yield, Total‐N, N Recovery, and Nitrate‐N Concentration of Three Cool‐Season Forage Grass Species1
Authors: George J. R. , Rhykerd C. L. , Noller C. H. , Dillon J. E. , Burns J. C. 
Published: July 2010

AbstractThis study was undertaken because of continued interest in replacement of legume N with commercial N for perennial grasses. More information is needed on the time and level of applied N to maximize total yield, seasonal distribution of forage, and efficient use of N fertilizer, while minimizing nitrate‐N accumulations in the forage. Timothy (Phleum pratense L.), smooth bromegrass (Bromus inermis Leyss.), and orchardgrass (Dactylis glomerata L.) were evaluated during the 1st (1964) and 2nd (1965) years after seeding. Nitrogen levels employed were O, 21, 42, 84, 168, and 336 kg/ha applied each harvest, providing maximum annual rates of 1,008 kg/ha for timothy and 1,344 kg/ha each for bromegrass and orchardgrass.Highest dry matter yields were obtained with orchardgrass, followed by bromegrass and then timothy. Yields were limited by drought in 1964, with timothy the most sensitive. Dry matter yields of orchardgrass and bromegrass exceeded 11,000 kg/ha in 1965, whereas timothy produced a maximum of 6,770 kg/ha. Production of orchardgrass was generally superior in midsummer. A low priority is suggested for timothy in the central and southern Corn Belt region due to its poor drought tolerance and low yield. Higher rates of N depressed forage yields, especially in 1965 due to a reduction in stand, with timothy affected most.Total‐N concentrations were similar in bromegrass and orchardgrass and generally lower in timothy. Recovery of applied N in the harvested forage was highest when 2 kg/ha of N was topdressed per harvest. Nitrogen recoveries were higher in 1965 with maximums of 48.5, 71.8, and 66.6% for timothy, bromegrass, and orchardgrass, respectively. These data suggest that established sod‐forming species may utilize applied N more efficiently than bunchgrasses, with timothy being quite inefficient presumably due to limited root volume and poor drought tolerance.Potentially toxic concentrations of nitrate‐N (.15%) were not found when N rates did not exceed levels required to maximize forage yield. The major exception occurred for July harvests of bromegrass and orchardgrass in 1965. These data suggest that bromegrass should be added to the list of species that could accumulate “unsafe” levels of nitrate‐N under certain conditions of N fertilization.
Leaf Blade Areas of Grain Sorghum Varieties and Hybrids1
Authors: Liang G. H. , Chu C. C. , Reddi N. S. , Lin S. S. , Dayton A. D. 
Published: July 2010

AbstractThe experiments were conducted to evaluate the amount of heterosis for leaf‐blade area in grain sorghum {Sorghum bicolor (L.) Moench} hybrids. Total leaf‐blade area was measured on plants of six varieties and their 15 hybrids, at two locations in 1971. Hybrids had significantly greater total leaf‐blade area, average leaf‐blade area, average leaf length and width, and grain yield as compared to parents. However, parents had significantly more leaves than hybrids. Differences between parents and hybrids for total leaf‐blade area, average leaf‐blade area, and average leaf‐blade width varied from location to location. Blade areas of leaves 2, 4, 5, 6, and 7 (flag leaf as number 1) of the hybrids were significantly larger than those of corresponding leaves of the parents. Total leaf‐blade area correlated positively and significantly with leaf‐blade area of the largest leaves, numbers 5, 6, 7 and 8. Adjacent leaves also correlated significantly with respect to blade size. Heritability for total leaf‐blade area was high.