bluuebunny/crossref_metadata_2025_split huggingface dataset:
Accelerating the Germination of Common Bermudagrass for Hydroseeding1
Authors: Young James A. , Kay Burgess L. , Evans Raymonds A. 
Published: July 2010

AbstractOur purpose was to obtain more rapid germination of common bermudagrass [Cynodon dactylon (L.) Pers.] for hydroseeding. Accelerated germination is especially valuable in hydroseeding where rapid germination is necessary to take advantage of the investments which are made in water, nutrients, and wood fiber to modify seedbed environments. Establishment may be improved by assuring germination soon after the initial application of these materails. Germination was determined for hulled seeds of common bermudagrass as affected by constant and alternating temperatures of 0, 2, and 5 C, and 5‐degree increments through 30 C, and at 40 C in the laboratory. Diurnal regimes consisted of 8 hours at the higher and 16 hours at the lower temperature. Phenological curves were developed for germination in relation to the optimum and near‐optimum temperature regimes. A 10/40 temperature regime produced high and rapid germination. Soaking of the seeds at this optimum temperature regime before hydroseeding would accelerate germination. Commercial application of presoaked seeds at 10/40 C would require refrigeration of the soaking liquid to reduce temperature to 10 C at night and heating to increase temperature to 40 C during the day. In addition, because of rapid germination at 10/40 C, in subsequent hydroseeding many seeds would have germinated exposing fragile radicles to turbulence of the pump action and relatively high nozzle velocities. A constant 30 C for 24 hours of preplant soaking is suggested as a practical alternative. We used 25 C for postsoaking incubation because it is a reasonable temperature existing at the time of most seeding. Maximum germination at 30 C required soaking in a solution of 1.0 mM potassium nitrate (KNO3) for triggering germination during the first 24 hours of incubation plus 0.035 mM gibberellin (GA) for accelerated germination and growth from 48 to 72 hours. Seedling growth through 96 hours was greatly enhanced by the further addition of 0.01 mM kinetin.
Soil Water‐Root Relations in Wheat: Water Extraction Rate of Wheat Roots that Developed under Dry and Moist Conditions1
Authors: Sharma R. B. , Ghildyal B. P. 
Published: July 2010

AbstractPrior investigations have reported modifications of various root characters of plants grown under relatively dry soil conditions, but there is a lack of information on the effect of these modifications on the capacity of root systems to extract soil water. This study was therefore conducted to investigate whether the root systems of wheat (Triticum aestivum L.) grown under different soil water conditions differed in their capacity to extract water from the soil.In a greenhouse experiment the water extraction rate per unit root volume was measured for two wheat (Triticum aestivum L.) genotypes grown for 60 days after sowing in pots maintained under three different soil water tension regimes of 0.3 to 0.8, 2.0 to 2.5, and 4.0 to 4.5 bars. The two genotypes under study were one gene dwarf Sonalika RR‐21 and three gene dwarf UP 301. The soil used was silty clay loam of the Mollisol order. Beginning on the 60th day after sowing the transpirational losses under different soil water tension regimes were measured for a period of 12 days by covering the pots with polyethylene sheet and weighing them intermittently. At the end of this 12‐day period volume, length, and dry weight of the roots were measured. The water extraction rate per unit root volume was calculated assuming that the transpirational loss was the amount of water extracted by the roots in a linear proportion to the root volume. The water extraction rate per unit root volume increased significantly with increasing soil water tension regimes. It varied from 7.91 cm3 H2O cm−3 root day−1 for UP 301 under the wettest regime of 0.3 to 0.8 bar to 9.11 cm3 H2O cm−3 root day−1 for Sonalika RR‐21 under the driest regime of 4.0 to 4.5 bar tensions. These findings suggest that root systems that developed under relatively dry soil conditions were capable of extracting greater amount of soil water on a unit root volume basis than those developed under moist conditions.
Physiological Development of Lehmann Lovegrass Seeds During the Initial Hours of Imbibition1
Authors: Haferkamp Marshall R. , Jordan Gilbert L. , Matsuda Kaoru 
Published: July 2010

AbstractData from both field and laboratory studies have suggested germination of Lehmann lovegrass (Eragrostis lehmanniana Nees.) caryopses (seeds) can be improved by various pre‐sowing seed treatments. Some of these treatments include moistening and drying, oven‐drying, scarification, and pre‐chilling on a moist substrate.The objective of this study was to determine if exposure of dry Lehmann lovegrass seeds to high humidity conditions, or to moisture under low temperature could effect rapid and detectable changes in their metabolic state. Seeds were (a) imbibed in cold water at 10 C (Treatment low), (b) exposed to a water saturated atmosphere at 24 C (Treatment 24v), or (c) imbibed in water at 24 C (Treatment 24w). For studies on physiological development, samples were collected after 6, 18, 31, 48, and 60 hours of treatment. Seed moisture content, germination percentage, rate of respiration, and ATP, ADP, alcohol soluble sugars, and starch contents were measured at each collection interval. In addition, α‐amylase activity was determined in air dry seeds, 24w seeds after 18, 31, 48 and 60 hours, and 24v and 10w seeds after 60 hours of imbibition.Physiological development of seeds was advanced in all treatments. Moisture content of the 24w, 24v, and 10w treated seeds increased 6.4, 3.0, and 5.1 fold, respectively. As the moisture content increased in the 24w seeds, the contents of ATP, ADP, and rate of respiration increased. The content of alcohol soluble sugars decreased from 1.88 to 1.20% during the initial 31 hours, but increased to 3.03% in the following 29 hours. This increase occurred with an increase in a‐amylase activity and subsequent active hydrolysis of starch. The 24v and low environments were unsuitable for germination, but ATP levels rose and starch and alcohol soluble sugars decreased slightly during the imbibition period. However, respiratory activity did not develop.
Germination of California Annual Range Plants in Response to a Summer Rain1
Authors: Raguse C. A. , Young J. A. , Evans R. A. 
Published: July 2010

AbstractDuring the period 7 to 9 July, 1974 the northern half of California experienced an unusual summer rain of 40 to 150 mm. This once‐in‐a‐century occurrence provided an opportunity to observe germination responses of resistant annual grasses, legumes, and forbs. Annual plants which have evolved in a Mediterranean climate generally are assumed to have acquired mechanisms for resistance to summer germination, which ordinarily would result in catastrophic losses of seedlings.Growth of resident and introduced annual range plants in response to the July rain was observed on grazed ranges at the University of California's Sierra Foothill Range Field Station, Browns Valley, Yuba Co. Transects were located on north‐ and south‐facing slopes consisting entirely of herbaceous vegetation. Square‐decimeter quadrats were sampled along the transects on 19 July, 30 August, and 18 October, and the seedlings found were counted and identified.Seeds of only a few annual species germinated and few plants were established in response to the summer rain. Species found were principally Bromus mollis L. (soft chess), Erodium botrys (Cav.) Bertol. (broadleaf filaree), Trifolium hirtum L. (rose clover), and T. subterraneum L. (subterranean clover). Seedling densities were low compared with emergence under normal fall rainfall. Moderation of the Mediterranean climate summer temperature regime by soil surface irregularities or by litter cover favored germination and emergence. Emergence also was better on north‐facing aspects than on south‐facing aspects.The data indicate that one characteristic of the many herbaceous annual species which have successfully invaded California since Gold Rush times is effective seed dormancy during summer. It is possible that this trait could prove useful in plant introduction screening.
Economic Optima and Price Sensitivity of N Fertilization for Six Perennial Grasses1
Authors: Colyer Dale , Alt F. L. , Balasko J. A. , Henderlong P. R. , Jung G. A. , Thang Vinh 
Published: July 2010

AbstractPrices of both nitrogen fertilizers and forages have increased in recent years causing concern about the profitability of fertilizing forage grasses. Yield response functions, which permit computation of economic optima, were estimated using regression analysis for Kentucky bluegrass (Poa pratensis L.), tall fescue (Festuca arundinacea Schreb.) orchardgrass (Dactylis glomerata L.), reed canarygrass (Phalaris arundinacea L.), smooth bromegrass (Bromus inermis Leyss.), and timothy (Phleum pratense L.). Experimental data from 3 years, 1968, 1969, 1970, with N treatments of 0, 112, 224, and 448 kg/ha were used to estimate the regression equations. Economic analyses were made with 3 N prices, 44, 55, and 66 cents/kg, and 5 forage prices, 2.2, 3.3, 4.4, 5.5, and 6.6 cents/kg. The economically optimal N treatment varied by species and was sensitive to changes in N‐forage price ratio, declining as the N price rose or the forage price declined. Fertilization with N was found to be profitable for all but very unfavorable price ratios.
Relationships Among Cottonseed Vigor and Emergence1
Authors: Buxton D. R. , Melick P. J. , Patterson L. L. , Pegelow E. J. 
Published: July 2010

AbstractBetter predictive methods of field emergence of cotton (Gossypium spp.) seedlings are needed than are presently available. In this paper we report on two types of relationships for predicting seedling emergence. The first is the association between field emergence and a vigor term of germinating seedlings called % transfer (ratio of plant axis weight to total weight of seedlings). The second is the relationship between time to 50% total emergence (ET50) and total emergence. Seed of diverse origin were germinated in the laboratory at 15 C for 8 days or at 25 C for 4 days and % germination, and % transfer were determined. Several field plantings were made, and periodic counts were made as seedlings emerged. The time course of germination of two lines that responded differentially in germination and field studies was examined by taking weights and seedling axis lengths repeatedly for 4 days at 25 C and 14 days at 15 C. Germination at 15 C for 8 days did not consistently predict field emergence better than germination at 25 C for 4 days. Some improvement occurred when germination parameters were averaged for the two temperatures. Combining % transfer with % germination into a term called “germination index” did not consistently aid in predicting field emergence over use of % germination alone, apparently because seed with high viability generally produced vigorously germinating seedlings. Percent transfer was negatively correlated with ET30. Predictability of the germination parameters was improved by extending the length of the germination period. Total emergence decreased linearly with increase in ET50. The average decrease ranged from just under 2% per day of ET50 to over 4% when the test involved a salt‐affected soil. We conclude that incorporation of these seed vigor terms into seed testing will not aid in predicting potential for cottonseed emergence. The relationship between emergence and ET50 should serve as an aid in making early decisions about replanting, although the nature of the relationship will probably depend upon local soil conditions.
Cerrado Vegetation in Brazil: An Edaphic Gradient1
Authors: Lopes A. S. , Cox F. R. 
Published: July 2010

AbstractThe vegetation in central Brazil is a tropical savanna called “cerrado” that varies from pure grassland to a nearly closed canopy of medium height trees overlying grass. Since forest is the expected climax vegetation there, several theories have been given to explain the types of grassland present. The more promising of these involve differences in soil properties, but only a few sites have been used for evaluation. To study these relaships in more detail and yet cover the bulk of the region, 518 composite topsoil samples were collected from a 600,00 km2 area. Laboratory characterizations included pH, exchangeable A1, nutrient levels (including micronutrients), organic matter content, particle size distribution, and color. The relationships between type of vegetation and differences in soil properties were evaluated statistically, primarily by correlation and regression. A positive gradient was found between the density and height of woody vegetation and the following soil properties: pH (H2O), pH (KC1), exchangeable Ca, Mg, and K, and extractable P, Zn, Cu, and Mn. As the percent of A1 saturation increased there was a decrease in density and height of woody vegetation. Neither exchangeable Al, particle size distribution, nor organic matter content showed a consistent gradient with the vegetative measure. There was a tendency for more dense stands of vegetation to occur on dark, reddish brown topsoil; while less dense stands occurred on brown to dark brown topsoils. The results suggest that the types of vegetation present in the region may best be explained by differences in soil properties, and it is recommended that soil Al be expressed by percentage Al saturation, rather than by its absolute value, in these relationships.
Influence of Seed Weight on Germination, Growth, and Development of Tobacco1
Authors: Kasperbauer M. J. , Sutton T. G. 
Published: July 2010

AbstractSeed size may influence germination rate and seedling vigor, which are important factors in innovative tobacco (Nicotiana tabacum L.) starting procedures such as seeding directly in the field or in transplantable containers. A study was conducted to determine relationships among tobacco seed weight, rate of germination, and seedling growth and development, including yield of cured leaf.Tobacco seeds were separated into three weight groups of 76, 65, and 50 mg/1,000 seeds. Germination was tested at 20 C in light and in uninterrupted darkness. The heavy seeds germinated earlier, in higher percentages, and over a shorter period of time than did the light weight seeds. The medium seeds were intermediate in these responses.Seeds from the three weight groups that germinated on the same date produced seedlings that did not differ significantly in size of transplants or in subsequent field growth and development, including leaf yield. However, seedlings from early and late germinating seeds within the same weight group differed significantly in size of transplants and in field performance. Even though the late seeds germinated only a few days after the early ones under optimal conditions, they produced seedlings that continued to lag in growth and development in the field and had a lower yield of cured leaf. Hence, heavy seeds that are light indifferent for germination should be used in tobacco starting procedures that require high germination percentages over a short period of time.
Effect of N Starvation of Soybean Plants at Various Stages of Growth on Seed Yield and N Concentration of Plant Parts at Maturity1
Authors: Streeter John G. 
Published: July 2010

AbstractEstimates of the minimum N concentrations of vegetative soybean (Glycine max (L.) Merr.) plant parts are needed to assess the N supplying capacity of these tissues during seed development. Also, little is known about how the plant responds to severe N stress during reproductive growth in terms of redistribution of N among plant parts and in terms of leaf senescence. The purpose of this experiment was to determine the effect of N starvation of soybean plants at various stages of growth on seed yield and N concentration of plant parts at maturity. Non‐nodulated soybean plants were grown in sand culture with a nutrient solution containing 100 mg N/liter and adequate levels of other major and minor elements. Nitrogen was withdrawn from the solution near the end of the flowering period or during rapid pod formation or during rapid seed formation; these withdrawal times were 65, 76, or 87 days after planting (DAP), respectively. The shortest period of N stress (withdrawal 87 DAP) resulted in marked decreases in individual seed weight and N concentration but did not result in premature leaf senescence or in a decline in N concentration of vegetative organs or a decline in the number of fruits and seeds per plant. Longer periods of N stress (N withdrawal 65 and 76 DAP) caused major reductions in pod and seed numbers as well as further decreases in seed weight and in N concentrations in seeds and vegetative organs. Concentrations of 1.0% N in leaves, 0.5%, N in stems, and 1.3% N in roots (dry basis), observed under conditions of extreme N stress, are estimates of the lower limits of N in these soybean tissues after maximum export of N. However, these lower limits were not reached until the amount of N stored in seeds was reduced by greater than 50%.
Nutrient Uptake by Grass and Leaching Losses from Soluble and S‐Coated Urea and KCl1
Authors: Allen S. E. , Terman G. L. , Kennedy H. G. 
Published: July 2010

AbstractSlow‐release fertilizers should provide for more efficient nutrient use by the crop as well as reduce leaching losses. This study was conducted to measure crop response to N or K in uncoated urea, ammonium nitrate (AN), S‐coated urea (SCU), KCl, and S‐coated KCl (SCK) and to relate leaching losses to NO3‐Nan and cations. In one series, granular N sources to supply 200 or 400 kg of N/surface ha were mixed with the upper 20 cm of a 1:1 mixture of Norfolk s1 (Typic Paleudult) and builders sand contained in 15‐ ✕ 120‐cm columns. A second series was similarly fertilized with K sources to supply 100 or 200 kg of K/surface ha.Soil columns were left fallow or planted to tall fescue (Festuca arundinacea Shreb. ‘Kentucky 31’) which was harvested six times at 4‐week intervals. Following the sixth harvest of fescue, stubble and roots were incorporated into the soil along with a second application of N or K and cultures were planted to sorghum‐sudangrass (Sorghum bicolor ✕ Moench Sorghum vulgare sudanense ‘Green M’), which was harevsted four times at 4‐week intervals. Water was applied as required for crop growth and once during each growth period all columns (including fallow) were heavily watered to collect liters (10 cm) of leachate from each.Total recovery of N by both crops was in the order: SCU‐12 > split‐AN > SCU‐20 > urea > AN > no N. With cropping, 0 to 11% of applied N was found in drainage water. Under fallow, losses of N were much higher (29 to 72%) and were in the order: split‐AN > SCU‐12 = SCU‐20 > AN = urea > no N. These results support the premise that slow‐release fertilizers supply more N for crop response, but may not reduce leaching losses. Leaching of cations was well correlated with loss of NO3‐N (r = 0.83 to 0.90) under fallow, but was less correlated (r = 0.33 to 0.74) under grass.Recovery of K by both crops was near 100%. Applied K decreased loss of NO3‐N, Ca, and Mg under cropping and increased losses under fallow. Leaching of NO3‐N and cations was highly correlated. Applied N and oxidation of S in S‐coated products both contributed to acidification of the soil, which intensified leaching of Ca and Mg.
Effect of Slow Release Fertilizer on Fertilizer Residues and on Yield and Composition of Flue‐cured Tobacco1
Authors: San Valentin G. O. , Robertson W. K. , Johnson J. T. , Weeks W. W. 
Published: July 2010

AbstractMany of the fine soils on which tobacco (Nicotiana tobacum L.) is grown do not retain applied K following irrigation or rainfall long enough to satisfy plant requirements. Losses should be reduced by the use of materials that restrict K solubility or by split application.Tobacco was grown for 5 years on Lakeland fine sandy soil (Typic Quartzipsamment), a soil which retains very little K. Split applications of K2SO4 were compared to single applications of K2SO4 and resin‐ polyvinyl‐, and S‐coated K materials. Yields and chemical composition of tobacco leaves and soil were used to measure the relative effectiveness of K treatments.Yields and K contents of tobacco leaves were increased by K fertilization. Split applications of K2SO4 were more effective than single applications at planting. In years with heavy rainfall, applying slowly‐soluble sources all at planting was better than applying K2SO4 in split application. Potassium from slowly soluble materials was less readily leached than from K2SO4, resulting in higher concentration of K within 60 cm of the surface at the time of tobacco flowering. When various thickness of S were applied to give a range of K release, the thicker coatings gave higher yields. Treatments that provided higher K contents increased total alkaloids and decreased reducing sugars in the first of the two years that they were measured. Application of K fertilizers with reduced solubility should assure good yields, quality, and a high level of K in tobacco.
Forage Yield and Fertilizer Recovery by Three Irrigated Perennial Grasses as Affected by N Fertilization1
Authors: Hanson C. L. , Power J. F. , Erickson C. J. 
Published: July 2010

AbstractIn many locations in the United States the livestock industry uses irrigated grasses for hay production. The purpose of this study, conducted in western South Dakota on heavy clay soils (Ustertic camborthids), was to determine forage yield responses and N recovery of three irrigated grasses‐reed canarygrass (Phalaris arundinacea), garrison creeping foxtail (Alopecurus arundinaceus), and smooth brome (Bromus inermis)—to single and split N applications. Single N treatments consisted of 0, 56, 112, 224, or 448 kg N/ha applied in March. For the split N applications, these same rates were applied both in March and again after the first hay cutting. Forage yields were maximum when the grasses were fertilized with 224 kg N/ha in the split applications. Maximum forage yields ranged between 8,899 kg/ha (air‐dried) for garrison creeping foxtail and 11,802 kg/ha for smooth brome. Split applications did not benefit total production at the 56 kg N/ha rate.First cutting forage N percentages varied between 0.8 and 1.3 for N rates of 56 to 224 kg N/ha and between 1.3 and 2.3 for N rates of 224 and above. The percentage of N was highest, frequently over 3%, in second cutting forage from treatments receiving split fertilizer applications.Percent total N recovered increased as fertilizer rate increased when all N was applied in March, but recovery was highest for the split application of 224 kg N/ha. Recovery by smooth brome forage was highest with split applications (up to 50% recovery), but was highest for the other grass species for single annual (March) applications.
Beta‐Nitropropionic Acid Concentration of Crownvetch Plant Parts as Affected by Growth‐Temperature‐Maturation Variables1
Authors: Faix J. J. , Gustine D. L. , Wright M. J. 
Published: July 2010

AbstractEarly meadow vole (Microtus pennsylvanicus) dietary trials on crownvetch indicated the presence of an adverse substance in the forage. Vole performance appeared to be related to forage source or to the effect of plant environment on the concentration of a deleterious substance. Betanitropropionic acid (BNPA) has since been identified in crownvetch as the deleterious compound. The objective of this study was to determine the influence of growth temperature on BNPA concentration in various plant parts of crownvetch forage. In this growth chamber study, BNPA concentration in crownvetch forage increased with increasing growth temperature. The most consistent increase in BNPA concentration occurred in the stem tips and leaflets, and the concentration in these parts averaged nearly twice that of the other parts. From this study it can be concluded that higher growth temperature can increase BNPA concentration in crownvetch forage and overall concentration can be influenced by the leafiness of the forage.