bluuebunny/crossref_metadata_2025_split huggingface dataset:
Productivity and Quality of Bermudagrass and Orchardgrass‐Ladino Clover Pastures for Beef Steers1
Authors: Fribourg H. A. , McLaren J. B. , Barth K. M. , Bryan J. M. , Connell J. T. 
Published: July 2010

AbstractBermudagrass (Cynodon dactylon (L.) Pers.) has high potential summer forage production and can help fill the gap in foragebeef production systems during late summer. The productivity and quality of ‘Midland’ grown at four levels of N fertilization (0, 112, 224, 448 kg.ha) as forage systems for grazing beef steers were compared to those of common bermudagrass (C. dactylon var. dactylon) fertilized with 112 kg N/ha and of a mixture of orchardgrass (Dactylis glomerata L) and ladino clover (Trifolium repens L.) (Orc.‐Lad.). Pastures were grazed by a put‐and‐take system to maintain bermudagrass pastures at an average height ≥ 3.5 cm and ≤ 10 cm, and Orc.‐Lad. ≥ 8 cm and ≤ 15 cm. Forage growth and consumption were estimated by the cage‐and‐strip method.Forage production and animal performance were different in all treatments for the two periods April through June (spring) and July through September (summer). Average length of grazing season (23 April to 12 September) was not affected by N fertilization. Bermudagrass production was similar in spring and summer, and was increased greatly by N in both periods. Forage production of Orc.‐Lad. was twice as large in spring as in summer. Average stocking rate ranged from 3.7 steers/ha on Midland‐0 to 9.9 on Midland448 in April through June, and from 2.7 steers/ha on 0rc.‐Lad. to 14.3 on Midland448 pastures in July through September. Animal grazing days/ha for the entire season ranged from 546 on Midland‐0 to 1,759 on Midland448 pastures.Total beef production (kg/ha) was 162, 283, 350, 605, 308, and 561 from Midland‐0, ‐112, ‐224, ‐448, Common‐112, and Orc.‐Lad. pastures for the entire season, respectively. These values were associated with average gains (weighted for period within season) of 0.33, 0.41, 0.38, 0.44, 0.49, and 0.84 kg/steer/day and estimated forage dry matter intakes of 8.2, 8.9, 6.0, 5.7, 8.1, and 8.7 kg/steer/day, respectively. Most of the beef production occurred in spring. High stocking rates were necessary to harvest grazable forage and maintain grass in a young leafy stage in Midland224 and ‐448 pastures; thus, grazing selectivity was minimized and probably led to low intakes. Since 112 kg N/ha were not sufficient to produce acceptable quantities of forage or beef, a rate of 175 to 200 kg/ha on Midland is recommended for the future. At that N level, Midland will produce more than common which, at lower N levels, outproduced Midland.
Leaf Conductance and Leaf‐Water Potential Relationships for Two Soybean Cultivars Grown Under Controlled Irrigation1
Authors: Carlson R. E. , Momen N. N. , Arjmand O. , Shaw R. H. 
Published: July 2010

AbstractBoth leaf‐water potential and leaf conductance are used singly or in combination as important indicators of soil moisture stress. The relationship between these two parameters may not be unique between species or even within a species, depending upon environmental conditions.These relationships were studied in soybeans [Glycine max (L.) Merr.] by growing plants in large potometers in the field under controlled soil moisture conditions. The potometers were previously filled with the top 15 cm of a Nicollet silt loam (Aquic Hapludolls, fine‐loamy mixed mesic). The plants were subjected to four independent drydown stress periods during critical reproductive stages of growth. Soil moisture was controlled by hand watering and the use of an automatic shelter, which covered the plots during periods of rainfall. Five levels of soil moisture were imposed during each of the four stress periods. Soil moisture was monitored with a neutron soil moisture probe, and leaf‐water potential was measured by using a pressure bomb. Leaf conductance data were collected using a diffusion porometer.Leaf conductance was significantly correlated with leafwater potential over most days; however, a unique nonlinear relationship between these two parameters was not established. Atmospheric demand, time of day, and some type of moisture stress hardening contributed as significant sources of variation. Although not consistent over all days, these two cultivars were shown to differ significantly in their leaf‐water potential, leaf‐conductance relationships.
Plant‐Parasitic Nematode Effects on Water Use and Nutrient Uptake of a Small‐ and a Large‐rooted Tall Fescue Genotype1
Authors: Elkins C. B. , Haaland R. L. , Rodriguez‐Kabana R. , Hoveland C. S. 
Published: July 2010

AbstractPlant‐parasitic nematodes often adversely affect tall fescue (Festuca arundinacea Schreb.) on sandy soils in the Southeast. Stand and yield reduction and damage to root systems by plant‐parasitic nematodes have been reported, but little is known about the effect of these nematodes on plant functions such as water use and nutrient uptake.A controlled‐environment room experiment was conducted to determine the effect of plant‐parasitic nematodes on water use and nutrient uptake of two tall fescue genotypes with differing root systems, and to determine the feasibility of developing plants with root characteristics that would minimize the detrimental effects of nematodes. One of the genotypes (AF‐81) had many small‐diameter primary roots with a median diameter of 1.0 mm. The other genotype (AF‐7) had fewer and larger roots with a median diameter of 2.2 mm. The two genotypes were grown in Cahaba loamy sand topsoil (Typic Hapludult, fine‐loamy, siliceous, thermic) with and without a mixed population of plant‐parasitic nematodes. Measurements were made of root development, water use, forage yield, and Ca, Mg, and K content of the forage.The small‐rooted genotype produced 30% more forage and was more efficient in water use than the large‐rooted genotype. Nematodes suppressed forage yield of the small‐ and large‐rooted genotypes by 9 and 50%, respectively, but had no effect on water use efficiency. Nematodes severely retarded root growth of the large‐rooted genotype, but had only a moderate effect on root growth of the small‐rooted genotype. The large‐rooted genotype supported twice the population of lance nematodes (Hoplolaimus galeatus [Cobb] Sher.) as did the small‐rooted genotype. Nematodes reduced forage Mg content of both genotypes to levels that could cause tetany in ruminants. Root size may be important in determining the effect of plant‐parasitic nematodes on plant performance and should be considered by plant breeders in developing nematode‐tolerant cultivars.
Nitrogen, Phosphorus, and Potassium Effects on Quality and Growth of Kentucky Bluegrass and Creeping Bentgrass1
Authors: Christians N. E. , Martin D. P. , Wilkinson J. F. 
Published: July 2010

AbstractMuch of the previous work involving the effects of N, P, and K on the growth and quality of turfgrasses has not involved methods by which the interactions among these nutrients, could be evaluated.In the present investigation, a double cube, composite, statistical design was used to investigate the N, P, and K requirements of Kentucky bluegrass (Poa pratensis L. ‘Merion’) and creeping bentgrass (Agrostis palustris Huds., ‘Penncross’) under controlled environmental conditions in sand culture. Nitrogen treatments ranged from 6 to 294 ppm, P from 2 to 98 ppm, and K from 4 to 196 ppm in solution. The objectives of the investigation were to study the effects of a wide range of N, P, and K levels on turfgrass growth and quality, and to observe the nutrient interactions.Quadratic relationships for dry tissue production of Merion in response to increasing levels of N and K were observed. Tissue production reached a maximum at 125 pprn N and 144 ppm K. Dry tissue production of Penncross in response to N was also quadratic, with a maximum at 96 ppm. Tissue dry weight increased linearly with K to the 196 ppm level. The most desirable quality characteristics for Merion occurred at the N concentration of 96 ppm, and a P concentration of less than 2 ppm. Maximum response to K was not reached at the 196 ppm treatment. Penncross attained these characteristics at a N concentration of 54 ppm and less than 2 ppm P. Again, maximum quality had not been reached at a K level of 196 ppm. Potassium may play a more important role in turfgrass fertilization than was previously realized. Penncross demonstrated maximum root production at a solution concentration of 6 ppm N and 196 ppm K. Minimum production of roots occurred at 150 ppm N and 64 ppm K. An interaction between N and K in solution was observed in the quality response of creeping bentgrass. As the level of K was increased, less N was required to attain maximum quality. It is possible that addition of higher levels of K to this species can affect its requirements for N. Additional work under field conditions will be required to evaluate the importance of this interaction.
Fescue Forage Production and Quality Response to Sequential Nitrogen Applications1
Authors: Smith A. E. , Calvert G. V. 
Published: July 2010

AbstractThere is a lack of formation concerning the influence of sequential applications of similar nitrogen rates on tall fescue (Festuca arundinacea Schreb. ‘Ky 31’) forage production. The purpose of this study was to determine the influence of the application of 240 kg ha−1 N, in differing annual sequences, on forage production and quality. In general, forage production was highest in plots receiving high (> 120 kg/ha) N rates just prior to the spring (April–May) and/or fall (August and September) periods of growth. Total annual production was highest (9,645 kg ha−1) in plots receiving 240 kg ha−1 N as a single application in March. Plots receiving single N applications in September and November and semiannual N applications in July and January produced in excess of 8,000 kg ha−1 forage. The IVDMD varied only six percentage units for all treatments, was highest in plots promoting highest production during March and October, and was lowest in forage from the check plots (receiving no N). Frequent applications of N increased forage production during June and August when compared to total annual application of N in March. High N rates applied in July allowed for increased vegetation composition of invaders in plot areas and the highest IVDMD.
Response of Alfalfa and Sorghum to Lime and P on Highly Weathered Soils1
Authors: Sumner M. E. 
Published: July 2010

AbstractOn highly weathered soils, crop response to low levels of lime is usually positive, corresponding to the neutralization of exchangeable Al and Mn, but response at high levels often becomes negative. Because the reasons for depressed yields when highly weathered soils are limed to near‐neutral pH values have not been adequately elucidated, two Oxisols (Typic, Umbriorthox) having similar properties but responding differently to lime were used to further probe the mechanisms involved. Alfalfa (Medicago sativa L.) and sorghum (Sorghum sudanense) were used as test crops in greenhouse experiments in which the levels of P and lime were varied. The depressive effect of high rates of lime appears to be linked with the presence of toxic levels of exchangeable Al before liming. Although this depressive effect can be overcome by the application of large quantities of P, it is not proposed that the effect is due primarily to exchangeable Al. Rather the level of exchangeable A1 at a given pH reflects the reactivity of the aluminous surfaces which, in turn, govern the solubility of P.
Growth Rates of Turfgrasses Propagated Vegetatively1
Authors: Busey Philip , Myers Barbara J. 
Published: July 2010

AbstractVegetative propagation is valuable as a cultural method in commercial sod production and as a tool in turfgrass research. Experiments were performed in the greenhouse and in the field in order to describe and compare growth rates in vegetative propagation of seven warm season turfgrasses. Daily growth rates were calculated as the logarithm of the quotient final/initial fresh weights, divided by the number of days between planting and harvest. By means of this criterion an elemental biological concept was demonstrated as a measure of rapidity of vegetative propagation and as a predictor of sod production time. The soil medium for most experiments was a Hallandale fine sand, a siliceous, hyperthermic, Typic Psammaquent. Maximum growth rates of turfgrass species ranged from l.8% per day for centipedegrass [Eremochloa ophiuroides (Munro) Hack.] to 9.2% for common bermudagrass [Cynodon dactylon (L.) Pers.]. These rates were larger than growth rates in commercial sod production, that were estimated to be no more than 2.6% per day. Duration of growth periods may explain the disparity between theoretical and observed growth rates. Growth periods of as long as two years are used in commercial sod production; much shorter intervals were used in our studies. A comparison of growth rates for various durations of growth periods suggested that for zoysiagrass (Zoysia japonica Steud.) and St. Augustinegrass (Stenotaphrum secundatum [Walt.] Kuntze) growth was not strictly exponential, but was sigmoidal. The levelling off of growth rates as turfgrasses become larger, or more densely sodded, may be explained by self‐inhibition through crowding. It appears possible to use frequent divisions to rapidly propagate warm season turfgrasses far initial increase of foundation blocks and experimental plantings. This and other cultural practices may be applied to improving the efficiency of commercial sod production. We propose the use of growth rate analysis as a method for describing and comparing cultural practices. Dry weight is preferred as the growth criterion, in contrast to fresh weight, coverage, or possibly other parameters. This simple model may be a powerful tool, as well, for testing genotypic response to pests and environmental stresses.
Forage Quality of Prostrate Kochia Compared with Three Browse Species1
Authors: Davis A. M. 
Published: July 2010

AbstractProstrate kochia [Kochia prostrata (L.) Schrad.], a shrub native to Asia, has received considerable attention because of its adaptation as a browse plant on western ranges. Prostrate kochia is a member of the Chenopodiaceae, the same family to which halogeton [Halogeton glomeratus (Bieb.) C. A. Mey.] and greasewood [Sarcobatus vermiculatus (Hook.) Torr.] belong. Both of these accumulate oxalates and can be toxic, depending on environmental conditions.This report presents data comparing crude protein, crude fiber, beta carotene, tannins, and oxalates of 13 prostrate kochia introductions to winterfat [Ceratoides lanata( Pursh.) J. T. Howell], an Iranian saltbush (Atriplex verrucifera Bieb.), and fourwing saltbush [Atriplex canescens (Pursh.) Nutt.], a favored browse plant native to the western range, during the browse utilization season of August to March.Two‐month‐old seedlings were transplanted to the field at Central Ferry, Wash. in early April. The soil was a Snake River bar alluvial classified as “Spofford” silt loam “fine‐silty, mixed, mesic typic Natrixerolls” with a pH of 6.7. Harvests were made at the end of the second and third growing seasons.Crude protein exhibited a regular downward trend from 14.7% to 8.9% in prostrate kochia, while fourwing saltbush varied from 13.60%, to 11.40%, and winterfat from 16.8% to 10.1%. Crude fiber increased from 19% to 42% in prostrate kochia. There was little change in fourwing saltbush and winterfat (14.6% to 17.8% and 30% to 33%, respectively). The highest tannin value was 7.0 mg/g in prostrate kochia, well below the critical level of 25 mg/g reported by E. D. Donnelly and W. B. Anthony in 1969. Oxalates averaged 1.20% in prostrate kochia, 1.75% in fourwing saltbush and 1.55% in winterfat. Using the 45 g critical level for sheep reported by H. L. Morton and coworkers in 1959, it would require daily consumption in excess of 2.25 kg of 2% oxalate forage before oxalates would be toxic. In August the carotene levels were comparable, but fourwing saltbush and winterfat were clearly superior during the winter months. Carotene levels dropped from 42 mg/100 g to 6.9 mg/100 g in January in prostrate kochia, but increased to 11 mg/100 g in March due to early bud development. The average of fourwing saltbush was 50 mg/100 g in August and 13 mg/100 g in March. Winterfat contained 50.5 mg/100 g in August, dropped to 19.6 mg/100 g in January, and climbed to 30.4 mg/100 g in March.
An Analysis of N Nutrition on Yield and Yield Components for the Improvement of Rice Fertilization in Korea
Authors: Vlek P. L. G. , Hong C. W. , Youngdahl L. J. 
Published: July 2010

AbstractThe statistical procedure of path coefficient analysis was applied to five field experiments conducted in Korea to help set criteria for the development of new controlled‐release fertilizers and fertilizer management practices tailored to flooded rice. The yield components which are most sensitive to N nutrition and the growth stages when N uptake is most efficiently translated into yield component development were identified.The experiments were conducted over a period of 2 years using two varieties of rice (Oryza sativa L., var. Tongil and Jinheung), two water management regimes (continuous and intermittent flooding), and three fertilizer sources (regular urea and two sulfur‐coated ureas) applied at four or five different levels of N. Continuously flooded experiments were conducted on an Aquic‐Fluventic Eutrochrept and the intermittently flooded on an Aquic‐Udipsamment. Yield response to N and apparent fertilizer N recovery varied with N source, rate, and variety, but in an inconsistent pattern. Close examination of yield component development as a function of N uptake revealed that variations in yield were mainly determined by panicle density and number of spikelets per panicle; the product of these components can serve as a potential yield index (PYI). The PYI is, to a large extent fixed by heading time and is closely related to the amount of N taken up between transplanting and heading. Path coefficient analysis was used to ascertain that N uptake during the period between 2 weeks after transplanting to maximum tillering most critically influenced PYI.
Effects of Broken Seed Coats on Field Emergence of Soybeans1
Authors: Luedders V. D. , Burris J. S. 
Published: July 2010

AbstractMechanical damage is a seed‐quality factor that may affect the worth of soybean [Glycine max (L.) Merr.] seed lots. Half soybean seeds (splits) can be sieved out of seed lots, but the relationship of splits, whole but damaged seed coats, and laboratory and field performance has not been investigated. Fifty uncleaned seed lots in each of 2 years were separated into clean seed, splits, small seed, and debris. The clean seed were tested for germination in sand and in rolled towels (RT) and also tested for emergence in four field environments. The percentage of seeds with broken seed coats was determined after imbibition for 15 min. Only data from seed lots with commercially acceptable germination (≥ 80%) were used. This reduced the sample sizes to 48 and 41 seed lots.Average germination was higher in sand than in RT (92.4 vs. 86.8%). Average field emergence (60.6%) was lower than laboratory germination and greater from 5‐cm than 10‐cm planting depth (78.6 vs. 46.2%). Percentages of broken seed coats and abnormal seedlings were negatively correlated with germination and emergence and positively correlated with each other. Correlation coefficients between splits and broken seed coats were only 0.51 and 0.31. Percentage of broken seed coats could not be used predict relative field emergeability of the seed lots as well as did RT or sand germination. Results of the two germination tests and the four field environments were positively correlated with each other in both years. Coefficients for a multiple regression equation were obtained using laboratory tests and one field emergence and then used to predict the other seven field emergences. The prediction was somewhat better than using RT germination alone but slightly poorer than sand germination six out of seven times. Results from this and other published experiments indicate that the standard germination test may predict relative field emergeability as well as any vigor‐stress test or index.
Soybean Stand Establishment and Yield as Affected by Herbicides and Cultural Practices1
Authors: Johnson R. R. , Wax L. M. 
Published: July 2010

AbstractWhen reduced soybean (Glycine max (L.) Merr.) stands occur, herbicides are often blamed for the problem. The object of this research was to determine if metribuzin [4‐amino‐6‐tert‐butyl‐3‐(methylthio)‐as‐triazin‐5 (4H)‐one] and/or vernolate (S‐propyl dipropylthiocarbamate) herbicides interact with other cultural variables to reduce stands and grain yield. Cultural variables researched in the field included soybean seed vigor, cultivar, planting depth, planting date, and surface versus incorporated herbicide application. In field experiments on a Typic Haploquoll soil herbicides were applied at slightly higher than recommended rates, and soybeans were seeded in 75‐cm row widths at a density of 350,000 seed/ha.In all experiments visual symptoms of herbicide leaf damage occurred, but herbicide treatments had minor effects on stand establishment and grain yield. In contrast, several other variables significantly reduced stands and grain yields. Differences in seedbed condition created by different planting dates altered stand establishment. Seed lots low in seed vigor (as measured by cold test germination) resulted in reduced stands and in some situations reduced grain yields when compared with high vigor seed sources. Compared with a 1.9 cm planting depth, a 3.8 cm planting depth reduced stands in crusted seedbeds. In contrast, the shallow depth caused stand problems in a dry seedbed. Of the cultural variables affecting stand establishment and grain yield, none exhibited a significant interaction with herbicide treatment. In a greenhouse study, extremely high vernolate rates were more detrimental to emergence of low vigor than high vigor seed. Our data suggests that even when visual symptoms of herbicide injury occur, cultural variables such as seedbed conditions, seed quality, and minor differences in planting depth are often the major variables causing stand problems.
Tillage Effects on Biomass Production and Moisture Utilization by Soybeans on Coastal Plain Soils1
Authors: Kamprath E. J. , Cassel D. K. , Gross H. D. , Dibb D. W. 
Published: July 2010

AbstractMany coarse‐textured surface soils in the southeastern Coastal Plain are prone to develop tillage pans which restrict root proliferation and moisture utilization in subsoils. The effect of tillage treatments on soybean [Glycine max (L.) Merr.] growth and soil moisture utilization was investigated on Norfolk sandy loam (Typic Paleudult) and Wagram loamy sand (Arenic Paleudult) soils. The three tillage treatments used were: conventional moldboard plowing and disking only before planting; or plowing and asking, followed by either chisel‐plowing; or subsoiling with bedding before planting. Measurements were made of top and root dry weight, leaf area, grain yield, soil water content and soil moisture tension.Breaking the tillage pan by chisel‐plowing or subsoiling increased top growth and leaf area of soybeans at full bloom. The percentage of roots below 30 cm was increased by subsoiling and chisel‐plowing when rainfall was below normal during the growth period. A higher proportion of roots was in the top 10 cm of soil with conventional tillage than with chisel‐plowing or subsoiling. Chisel‐plowing and subsoiling increased the amount of soil moisture utilized below a depth of 30 cm. Grain yields were increased by chisel‐plowing or subsoiling in those years when rainfall was below normal during lateflowering and the beginning of pod development.Subsoiling or chisel‐plowing of soils with compacted pans will increase soybean yields during years in which below‐average precipitation occurs during late‐flowering and the beginning of pod set. Yield increases are attributed to increased root proliferation below the pan and greater utilization of subsoil moisture.