bluuebunny/crossref_metadata_2025_split huggingface dataset:
Combining Experiments to Predict Future Yield Data1
Authors: Cady Foster B. , Allen David M. 
Published: July 2010

AbstractData front a series of fertility experiments including uncontrolled environmental variables are analyzed so that future yields may be predicted. Existing regression procedures for selecting variables in an estimated prediction equation had been found to perform poorly when used for new sets of similar data. A new criterion, the prediction sum of squares, based on the performance of the estimated equation for predicting observations not included in the least squares estimation, is developed for selecting the best predictor variables. The procedure gives an estimated prediction equation with a minimal number of predictor variables, including few interaction variables. Agronomically reasonable estimates of the regression coefficients also are obtained. Using the new procedure, a 30% reduction in the sum of squared deviations between the observed and the predicted observations compared with the stepwise regression method is found. Response curves are constructed for use in making soil test recommendations.
Effects of Stalk Chopping on Leaf Removal and Juice Quality of Rio Sweet Sorghum1
Authors: Broadhead Dempsey M. 
Published: July 2010

AbstractMechanized stripping is essential for survival of the sweet sorghum sirup industry and continued development of the sweet sorghum sugar industry.‘Rio’ sweet sorghum [Sorghum bicolor (L.) Moench.] was planted April 1 and 15, May 1 and 15, and June 1 and 15 and harvested in flower, milk, dough, and ripe stages and at 1, 2, 3, and 4 weeks after ripe stage of maturity. Stripped stalk samples from each planting date and harvesting stage were chopped into 10‐, 20‐, and 40‐cm sections on a bench saw and compared with whole stalks in storage for 0, 24, and 48 hours. Unstripped stalks were chopped into 10‐, 20‐, and 40‐cm sections to evaluate chopping as a technique for separating leaves and stalks. Chopping the stalks into short sections was an effective method of separating leaves from the stalks. Under the conditions of these experiments no important losses were indicated in juice quality, as measured by Brix, sucrose, and purity of stalk sections when compared to whole stalks of sweet sorghum in storage for 0, 24, and 48 hours.
Nitrogen Nutrition of Field‐grown Soybean Plants: I. Seasonal Variations in Soil Nitrogen and Nitrogen Composition of Stem Exudate1
Authors: Streeter John G. 
Published: July 2010

AbstractThis study was undertaken to document the quantities of N compounds present in soil and in stem exudate from soybeans throughout most of the life cycle of the plant. The results provide new information on the relative importance of various N compounds involved in translocation and the relation of these compounds to soluble N of the soil.Soybean plants (Glycine max L. Merr., ‘Harosoy 63’) were grown under field conditions in Wooster silt loam with four replications. Nodules formed on the roots early in the season, and plants were well nodulated throughout the growth period. Plots were sampled at 13 times during the growing season for the determination of soil moisture, nitrate and ammonium content of the soil, and nitrate, nitrite, and amino acid content of stem exudate.Exudate flow rate appeared to be related to soil moisture content early in the season but the relationship was not maintained after the flowering stage. Nitrite was not detected in stem exudate. Nitrate content of the soil and the exudate was highest during the growing stages preceding flowering. During growth stages following flowering the amino acid concentration in the exudate was many times the nitrate concentration, which did not vary with fluctuations in nitrate content of the soil. Asparagine was the predominant amino acid in the stem exudate at all harvest dates; asparagine N as per cent of total amino acid‐N was 61% over the entire experiment. The grand mean for amino acid‐N concentration in exudate was double the grand mean for nitrate‐N concentration.
Noncompetitive Effects of Giant Foxtail on the Growth of Corn1
Authors: Bell David T. , Koeppe D. E. 
Published: July 2010

AbstractWeed infestations severely reduce the yield grown corn with such yield reductions generally being attributed to competition. Noncompetitive (allelopathic) mechanisms have to date, however, received little consideration in agronomic situations. In the greenhouse, interference (competition + allelopathy) of the growth of corn (Zea mays L. Wf9 ✕ M14) by giant foxtail (Setaria faberii Herrm.) was determined in mixed culture treatments. When corn was seeded into pots with 6‐week‐old giant foxtail, corn height, fresh weight, and dry weight were reduced by as much as 90% when compared to comparable plants grown in monoculture. Competitive and allelopathic mechanisms were separated through the use of a stairstep apparatus, in which a nutrient solution passed through the rhizosphere of giant foxtail, into the rhizosphere of corn and was subsequently recycled through the system. The stairstep apparatus was used to determine the allelopathic interactions between corn and giant foxtail seedlings, mature giant foxtail, whole dead giant foxtail plants, and mascerated dead giant foxtail leaf and root material. Mature giant foxtail inhibited the growth of corn approximately 35% through an allelopathic mechanism. Elimination of competition through the use of stairsteps apparatus implicates a possible allelopathic mechanism in the interference of corn by giant foxtail that involves the exudation and leaching of phytotoxins from the roots of giant foxtail. Phytotoxins leached from dead giant foxtail reduced corn growth by as much as 50%. The relationships of allelopathy to competition, crop rotation, herbicidal activity, and physiological processes are discussed.
Soil Surface Water Depletion and Leaf Temperature1
Authors: Aston A. R. , van Bavel C. H. M. 
Published: July 2010

AbstractThis work explores the feasibility of the remote detection of water depletion in a cropped field. It proposes that this may be accomplished by detecting the increase in the visible and thermal radiant heat loads upon plant leaves when the underlying soil surface dries. A theoretical model was constructed, relating leaf temperature to soil surface temperature.Parallel experiments were done using a grey podzolic soil. It was found that in spite of an increase of 15% in reflectivity upon drying, there was an increase in soil surface temperature from 20 to 50 C. The increased shortwave and longwave radiant loads on leaf arrays in the experiments, resulted in leaf temperature increases of 2.5, .5, and 2 C in dry blotting paper, wet blotting paper, and leaves of the southern pea (Vigna sinensis), respectively.The leaf energy balance‐soil water depletion model predicted these increases, as well as the absolute temperatures, with an accuracy of 1 and 5% for the artificial and real leaves, respectively.The findings of this study affirm that a technology can be developed for the remote detection of soil water depletion in field crops, but that the temperature differences involved are both small and variable.
Nature of Scion Control of Mineral Accumulation in Soybeans1
Authors: Polson D. E. , Smith L. J. 
Published: July 2010

AbstractA modified grating technique was used to study scion control of mineral accumulation in soybeans [Glycine max (L.) Merrill]. With this technique the shoot is left intact and a second scion or shoot is grafted into the first. We compared mineral accumulation in the original and graft shoot using this technique to determine if scion control of ion accumulation is accomplished within the shoot itself or if the shoot acts through altering root characteristics.Grafts were made in all combinations among four genotypes differing in accumulation levels for a number of ions. The original and graft shoot accumulated different levels of P, K, Ca, Mg, Sr, and B in seed, depending upon the genotype of the original and graft shoot. Accumulation in original shoot leaves was independent of the graft genotype. Accumulation in graft shoot leaves was primarily a function of the graft shoot genotype, although the original shoot had some effect on accumulation of P, Ca, Mg, Zn, and B. These results indicate that ion accumulation in the original and graft shoot is largely independent, suggesting that scion control of ion accumulation is accomplished via a self‐contained mechanism within the shoot.
Effect of Planting Date and Maturity on Juice Quality of Rio Sweet Sorghum1
Authors: Broadhead Dempsey M. 
Published: July 2010

AbstractEconomical production of granulated sugar from immature sweet sorghum stalks would extend the milling period for several weeks each year.‘Rio’ sweet sorghum [Sorghum bicolorz (L.) Moench.] was planted April 1, May 1, and June 1 and was harvested in the flower, milk, dough, and ripe stages of maturity. Samples from each planting date and harvesting stage were stored openly on the ground for 0, 24, and 48 hours before milling. The juice was weighed and analyzed for Brix, sucrose, and purity to compare the effect of maturity and storage on juice quality.Yield of stalks from the April 1 and June 1 plantings were similar but significantly lower than from the May 1 planting date. Stage of maturity had no effect on yield of stalks. Extraction generally decreased with maturity, whereas Brix and starch increased. Sucrose increased with maturity through the dough stage and purity increased from flower to milk stage.Extraction and purity decreased during 24 hours in storage, and sucrose and starch decreased during 48 hours in storage. Sucrose inversion was highly significant in stored stalks harvested in the flower and milk stages, which resulted in a highly significant decrease in purity. Mature stalks showed little or no inversion during storage. Juice purity was similar for Rio stalks harvested in the milk, dough, and ripe stages of maturity and not stored. After 24 hours in storage purity of stalks harvested in the milk stage was significantly lower than that of those harvested in the dough and ripe stages.
Interaction of Nematodes and Soil Temperature on Growth of Three Tropical Grasses1
Authors: Boyd F. T. , Schroder V. N. , Perry V. G. 
Published: July 2010

AbstractYields of several pasture grasses in Florida are seriously reduced by nematodes. This study investigated the relation between soil temperature and growth of grasses.Three tropical grasses were planted in soil infested with parasitic nematodes and were grown under greenhouse conditions at eight temperature levels. These temperature levels were established in a water‐bath consisting of an insulated, copper‐lined, wooden tank equipped with electrical heating and cooling controls.Soil temperatures influenced the amount of plant injury from parasitic nematodes, but the degree of such injury was dependent on the type of nematode present and on the susceptibility of the host plant.Sting nematodes (Belonolaimus longicaudatus Rau) were most active at soil temperatures between 20 and 34 C. Pensacola bahiagrass (Paspalum notatum Flugge) and limpograss [Hemarthria altissima (Poir) Stapf et C. E. Hubb P.I. 299994] produced greatest forage yields when soil temperatures were between 34 and 38 C. At the temperatures tested above 38 C, sting nematodes were greatly reduced, but ring nematode (Criconemoides spp. Taylor) populations were maintained. Forage yields of pangola digitgrass (Digitaria decumbens Stent) were highest when grown at temperatures between 38 and 41 C.
Effect of Day/Night Temperature on Factors Associated with Growth of Nicotiana tabacum L. in Controlled Environments1
Authors: Haroon Mohammed , Long R. C. , Weybrew J. A. 
Published: July 2010

AbstractGrowth of flue‐cured tobacco (Nicotiana tabacum L.), ‘NC2326,’ was studied under controlled conditions in the North Carolina State University Phytotron (Southeastern Plant Environment Laboratory) to determine the patterns of growth over a wide range of day/night temperatures. Day temperatures ranged from 18 to 34 C at 4‐C intervals; night temperatures ranged from 14 to 30 C at 4‐C intervals. The growth of seedlings from first leaf to transplant size (Experiment I) was determined weekly intervals under all possible day/night temperature combinations. Fresh weight, dry weight, and leaf number were affected to a greater extent by night than by day temperature. The minimum night temperature for growth lies between 18 and 22 C. The 34/30 treatment yielded maximum fresh and dry weights, while maximum leaf number occurred under the 34/26 treatment. Diurnal variation in temperature favored increased growth. During early stages of seedling growth fresh and dry weight accumulation exhibited a bimodal response to day temperature.The growth of plants from transplant size to appearance of the first flower (Experiment II) was studied under the following day/night temperatures: 34/30, 30/26, 26/22, 22/18, and 18/14. Whole‐plant fresh and dry weights, leaf fresh and dry weights, leaf number, and plant height increased with temperature to 30/26, but decreased slightly at 34/30. Days‐to‐flower decreased with temperature to 26/22 and then increased at higher temperatures.
Influence of Subsurface Barrier on Growth, Yield, Nutrient Uptake, and Water Requirement of Rice (Oryza sativa)1
Authors: Rao K. V. P. , Varade S. B. , Pande H. K. 
Published: July 2010

AbstractGrowth of rice (Oryza sativa) under flooded conditions in Southeast Asia results in excessive water and N losses. This investigation was conducted to determine the effect of subsurface barriers of bitumen and concrete on yields of rice grown with 60, 90, and 120 kg/ha of N. Yields of rice grown over the subsurface barriers were significantly higher than those grown on the control. The increase in growth and yield of rice was attributed to increased uptake of N, P, and Fe rendered available due to conducive redox potential. Rice produced significantly higher yields with 90 or 120 kg/ha of N than with 60 kg/ha. Subsurface barriers reduced the water requirement drastically and increased water use efficiency.
Crop Response to Phosphate Fertilization and to Residual Phosphate Levels: II. Evaluation of Residual Phosphorus “Availability” by Chemical and Plant Tests in a Greenhouse1
Authors: Giskin M. , Hagin J. , Kafkafi U. 
Published: July 2010

AbstractYield response in two field experiments was found to be a poor indicator of phosphorous “availability”. This greenhouse experiment was performed in order to obtain an indicator of “availability” based on plant response in addition to those based on soil extraction methods.Bulk samples of soil were taken from each of 16 treatments of two field experimental sites (Neve Yaar and Lachish) on which eight consecutive crops had been grown and differentially fertilized. The residual P levels (NaHCO3‐soluble P) ranged from 5.5 to 24 ppm P. The greenhouse treatments consisted of four levels of phosphate applied as triple superphosphate in amounts of 0, 40, 100, and 250 ppm P to pots containing 3 kg of soil.Within greenhouse treatments, at any one residual level, the absolute yield on the Lachish soil increased with increasing rates of P application. For the Neve Yaar soil this held only up to a residual level of 11 ppm P. In both soils, with few exceptions, the larger the residual P level (field treatments), the smaller the yield increase due to the fertilizer treatments given in the greenhouse (i.e., at residual level of 5.6 and 24 ppm P the step wise dry matter yield increases were from 1.29 to 6.25 and 4.40 and 5.31 g/pot respectively).Relative yields, chosen as an indicator of P “availability” in soil, of the nonfertilized pots of the greenhouse experiment were correlated to amounts of P applied in the field. Relative efficiencies of the residual phosphate accumulated in the field experiments, as described by the slopes of the regression lines, showed an inverse dependence on the heavy superphosphate applications (48–432 kg P/ha) applied to the field experiments. This suggests a higher efficiency of fertilizer P, can be obtained on calcareous soils, when applied in small annual amounts.
Essentiality of Molybdenum for Alfalfa on Highly Oxidized Piedmont Soils1
Authors: Giddens Joel , Perkins H. F. 
Published: July 2010

AbstractProduction of alfalfa (Medicago sativa L.) has steadily declined on highly oxidized soils of the Southeast during the past decade. An investigation was conducted to determine if lack of Mo is responsible and if lime or N replaces the Mo requirement of alfalfa and if there are other alternatives such as use of CaSO4 and Mo to replace lime, MgCO3 substitution for CaCO3, and if high initial lime applications may replace lesser annual applications. Field investigations using two highly oxidized Udults revealed that neither N at 67 kg/ha, nor lime at initial rate of 11,200 kg/ha or annual applications of 2,240 kg/ha replaced the Mo requirement of alfalfa. Nitrogen increased crabgrass (Digitaria sp.) competition, which resulted in less alfalfa forage. Calcium from CaSO4 with or without Mo did not maintain alfalfa. MgCO3 and CaCO3 applied at equivalent rates were equally effective as liming materials. An initial lime treatment of 11,200 kg/ha produced yields equal to that obtained by annual application of the same total amount of lime over a 5‐year period.
Effect of Source and Rate of Nitrogen on N Uptake and Fertilizer Efficiency by Spring Wheat and Barley1
Authors: Alessi J. , Power J. F. 
Published: July 2010

AbstractField experiment was conducted to determine the effect of fertilizer N source and rate on N uptake and recovery by small grains. Five N sources — NH4NO3, (NH4)2SO4 Ca(NO3)2, Uramite, and Nitroform (urea‐formaldehyde) — were applied to Temvik silt loam for 4 years at rates of O, 34, and 68 kg N/ha to spring wheat (Triticum aestivum L.) and barley (Hordeum vulgare L.) under an annual dryland cropping system. Residual responses were measured until effects were no longer significant. N content of plants was usually increased at all stages of growth by all N sources; N uptake was greatest for the ammonium and nitrate sources at the 68‐kg rate. At the end of the residual period, recoveries averaged 78% for the ammonium anl nitrate sources, and 44% for the urea‐formaldehyde materials. Recoveries increased by 12 to 29% during the residual period, with the greatest increase occurring for the calcium nitrate treatment. Highest average N recovery for the 8‐year period was 87% for Ca(NO3)2. No accumulation of NO3‐N remained in the upper 180 cm of soil at the end of the experiment.Results from this long‐term study indicate that ammonium and nitrate sources of fertilizer N are superior to urea‐formaldehyde for small grain production in semiarid regions.
Influence of Planting Method and Plant Population on Cotton (Gossypium hirsutum L.)1
Authors: Bridge R. R. , Meredith W. R. , Chism J. F. 
Published: July 2010

AbstractTo determine the effects of variations in plants/hill, within‐row plant spacings, and plant populations on the agronomic and fiber properties of cotton (Gossypium hirsutum L.), we evaluated the performance of ‘Deltapine 16’ when planted in hills and drilled at five populations over a 3‐year period (1969‐71). Hills were spaced 38 cm apart. The hills were thinned by hand to one, three, five, seven, and nine plants/hill, representing a range in population of 24,700 to 222,300 plants/ha. Plants in the drill plantings were spaced approximately 38.0, 12.7, 7.6, 5.3, and 4.3 cm apart to provide approximately the same populations for the hill‐dropped and drill‐planting method.Significant differences in yield due to populations were found, but planting method had no significant influence on yield. The highest yields each year were obtained in a population range of 70,000 to 121,000 plants/ha. In 2 out of 3 years the highest yields were obtained with a population of 114,000 to 121,000 plants/ha (five plants/hill or plants spaced 7.6 cm apart). Significant differences in lint percentage, boll size, and seed index were due to populations. The combined data indicate no appreciable differences in lint percentage; lint percentage of the low population, however, was significantly higher than that of the two highest populations in 2 of the 3 years. Boll size gradually decreased as plant population increased, with the lowest population usually producing significantly larger bolls and seed.We found that plant populations had no consistent effects on fiber length, strength, and elongation. The differences were small in magnitude and of no practical value. Micronaire tended to decrease as population increased.
Forage Production on Bermudagrass Sods Overseeded with Tall Fescue and Winter Annual Grasses1
Authors: Fribourg Henry A. , Overton Joseph R. 
Published: July 2010

AbstractBermudagrass (Cynodon dactylon), widespread in Tennessee, furnishes forage from April to October and is dormant during the remainder of the year. This study was conducted to determine whether the season of forage production from such dormant sods could be extended by overseeding annual and perennial cool‐season grasses, and to determine their effects on warm‐season grass production. Established sods of common and ‘Midland’ bermudagrasses growing on Loring, Grenada, and Falaya soils were overseeded in 50‐cm rows in October 1965, 1966, and 1967, after bermudagrass growth had stopped, with ‘Monon’ wheat (Triticum aestivum L.), ‘Blount’ oats, (Avena sativa L.), ‘Balbo’ rye (Secale cereale L.) and Italian ryegrass (Lolium spp.). ‘Kentucky 31’ tall fescue (Festuca arundinacea Schreb.) was seeded in 50‐cm rows in October 1965 and 1966 and in 25‐cm rows in 1967. Summer production of bermudagrass grown alone, which ranged between 6 and 10 t/ha of dry matter, was depressed by annuals seeded the previous autumn. Overseeded small grains clipped during winter produced 1.4 to 3.0 t/ha dry matter and wheat harvested at late boot furnished 3.5 to 4.4 t/ha. Ryegrass yielded 3.5 to 5.0 t/ha during late winter and spring. Overseeding of the annual species resulted in higher total yields per unit area each year and extended the length of time forage was growing and available. Excellent stands of tall fescue were obtained and maintained through 1972. Fescue decreased Midland bermudagrass production by about 30%, and that of common by about 40%. However, fescue production in spring, summer, and fall compensated for the decreased bermudagrass production, increased total yearly forage production by about 2 t/ha, and extended the potential grazing season from 5 to 8 to 9 months.