bluuebunny/crossref_metadata_2025_split huggingface dataset:
Assessment of Visual Evaluation Techniques1
Authors: Horst G. L. , Engelke M. C. , Meyers W. 
Published: July 2010

AbstractVisual evaluation parameters are routinely used to assess performance characteristics of turfgrass cultivars in field plantings. Rating systems are commonly employed to evaluate phenotypic variations in color, density, and uniformity of turfgrass stands during the year. In the present study, visual assessment data for quality and density ratings of cultivars of Kentucky bluegrass (Poa pratensis L.) and tall fescue (Festuca arundinacea Schreb.) from 10 turfgrass researchers were statistically analyzed to determine data conformity, consistency, and uniformity. Analysis of simultaneous data gathering by 10 investigators indicated the following: 1) Visual assessment scales were significantly different among evaluators, 2) Visual criteria used for data collection allowed a wide latitude of perception in quality and density characteristics, 3) Relative rank performance of cultivars differed among evaluators, and 4) Presently accepted techniques for visually assessing turfgrass quality and density are inadequate. Results of national and regional turfgrass cultivar evaluation trials should be considered with caution as most performance variables are based on the use of conventional evaluation schemes. This study emphasizes the need for a coordinated development of qualitative evaluation techniques based on substantiated, biologically definable, growth responses rather than visual perception.
Interactive Effects of Salinity and Substrate Phosphate on Soybean1
Authors: Grattan S. R. , Maas E. V. 
Published: July 2010

AbstractPreliminary experiments at this laboratory indicated that salt injury of soybeans [Glycine max (L.) Merr.) is strongly dependent upon the inorganic phosphate (Pi) concentration in the substrate. Inorganic phosphate concentrations that are commonly used in nonsaline solution cultures were lethal to ‘Kanrich’ and ‘Prize’ cvs. in saline media. A solution culture experiment was conducted in the greenhouse to examine the interactive effects of salinity (−0.04, −0.24, and −0.44 MPa osmotic potential) and substrate Pi (0.02,0.10,0.20, and 0.30 mmol L−1) on shoot and root growth, foliar injury, and tissue element concentration on five soybean cvs. [‘Clark’ (P‐sensitive), ‘Jackson’ (salt‐sensitive, P‐tolerant), ‘Lee’ (salt‐tolerant, P‐tolerant), ‘L63‐1677’ (P‐tolerant), and Kanrich]. Increased Pi had no effect on growth under nonsaline conditions but in the presence of salinity it significantly reduced shoot and root growth of Clark and Kanrich cvs. only. High salinity (−0.44 MPa) in combination with Pi ≥ 0.10 mmol L−1 killed both Clark and Kanrich cvs. However, at 0.02 mmol L−1 Pi and high salinity, no foliar injury was found on Kanrich and only slight chlorosis was found on Clark. In contrast, no foliar injury was apparent on Lee in any treatment. Inorganic phosphate increased the severity of injury in L63‐1677. Salinity greatly enhanced Pi accumulation in leaves and roots of Clark and Kanrich; whereas this effect was slight for the P‐tolerant cvs. Lee, Jackson, and L63‐1677. Injured Clark and Kanrich leaves contained abnormal amounts of P (400 to 800 mmol kg−1, dry wt) indicating that the primary cause of injury was a salinity‐induced Pi toxicity. Salinity also induced considerable foliar injury on Jackson; yet the onset and severity was independent of the substrate Pi concentration. Unlike the mechanism of foliar injury in Clark and Kanrich, we suspect injury in Jackson was caused by Cl toxicity. The striking adverse interaction between salinity and phosphate is a critical factor in solution culture studies of plant tolerance to salinity. These results further demonstrate that important genetic differences exist among cultivars that greatly affect their susceptibility to Pi toxicity.
Abscission, Total Soluble Sugars, and Starch Profiles within a Soybean Canopy1
Authors: Antos Matthew , Wiebold W. J. 
Published: July 2010

AbstractReproductive abscission is greatest in the lower one‐third of soybean (Glycine maxL. Merr.) canopies. It has been hypothesized that low carbohydrate availability is responsible for abscission of soybean flowers and pods, The cv. Williams was used to determine canopy distribution of flower and pod number, reproductive abscission, and the concentration of total soluble sugars (TSS) and starch in soybean leaflet, petiole, stem, and reproductive tissues. The plants were field grown (Beltsville silt loam; a fine‐loamy, mixed, mesic Typic Fragiudult) and harvested four times during reproductive development (R1.5, R3.0, R5, R6). Two treatments, no shade and 75% shade, were used. Shades were in place 11 days for each physiological stage. Flower number, pod number, and reproductive abscission percentages were determined during these 11 day periods for both treatments. All characters were determined for three strata within the canopy. Total abscission throughout the growing season was 68 and 61% in 1978 and 1979. Abscission within the upper, middle, and lower strata, averaged over 2 years, was 38, 59, and 98%, respectively. Partial shade increased percent abscission at R3 and R6 of 1978 and not at all in 1979. In 1978, TSS concentration within leaflets, petioles, and stems reached a maximum value at R5, R3, and R6, respectively. In 1979, TSS of petioles and stems increased throughout reproductive development, but TSS of leaflets fluctuated between stages. Stage of development had an effect only on the starch concentration of petioles. In this instance maximum starch concentration occurred at R5. Significant canopy strata effects on TSS and starch concentration of stems and petioles were found at most stages of development. In these instances, concentrations of the lower one‐third canopy were smaller than concentrations of the middle and/or upper canopy region. Large abscission percentages were associated with small concentrations of stored carbohydrates.
Salinity Effects on Seed Yield, Growth, and Germination of Grain Sorghum1
Authors: Francois L. E. , Donovan T. , Maas E.V. 
Published: July 2010

AbstractGrain sorghum (Sorghum bicolor(L.) Moench] is grown on saline soils in the western United States. Because of the lack of information on salinity effects on seed yield, a field plot study was conducted. Six saline treatments were imposed on a Holtville silty clay (clayey over loamy montmorillonitic (calcareous), hyperthermic Typic Tor‐rifluvents) by irrigating with waters that were salinized with NaCl and CaCl2(1:1 by wt). The electrical conductivities of the irrigation waters were 1.5, 2.7, 5.0, 7.4, 9.8, and 12.1 dS/m. Germination, vegetative growth, and grain yield were measured. Relative grain yield of two cultivars, Double TX and NK‐265, was unaffected up to a soil salinity of 6.8 dS/m (electrical conductivity of the saturation extract: Κe). Each unit increase in salinity above 6.8 dS/m reduced yield by 16%. This indicated that grain sorghum is moderately tolerant to salinity. Yield reduction was due primarily to lower weight per head rather than a reduced number of heads. Vegetative growth was affected less by increasing soil salinity than was grain yield. Grain sorghum was significantly more salt tolerant at germination than at later stages of growth.
Moisture Sensor‐Controlled Irrigation for Maintaining Bermudagrass Turf1
Authors: Augustin B. J. , Snyder G. H. 
Published: July 2010

AbstractThe feasibility of tensiometer soil moisture sensing devices for scheduling bermudagrass (Cynodon dactylon× C. transvaalensis) turf irrigation and their impact on N fertilization practices under sub‐tropical conditions was assessed. Irrigation water savings of 42 to 95% were obtained in sensor controlled plots over conventionally irrigated plots. The greatest benefit of the sensor system was achieved during periods of frequent but unpredictable rainfall by eliminating unnecessary irrigations. Application of a wetting agent was necessary during extended dry periods to prevent localized dry spots when irrigation was limited by the sensor system to an as needed basis. Reduced irrigation by the sensor system resulted in better turf appearance and equal effectiveness of water‐soluble and slow‐release N sources.
Salt Tolerance of Grasses and Legumes for Roadside Use1
Authors: Greub L. J. , Drolsom P. N. , Rohweder D. A. 
Published: July 2010

AbstractSalt injury to grasses and legumes in roadside seedings is becoming an increasingly serious problem in areas where deicing salt is used during winter months. This paper reports on results of three greenhouse trials conducted to evaluate salt tolerance among 40 grass and legume species, cultivars, and genotypes. A 2.65 M sodium chloride (NaCl) solution was added weekly for up to 5 weeks to pots of seedling plants in a Derinda silty clay loam (fine, mixed, mesic Typic Hapludalfs). Salt tolerance was measured by comparing dry matter (DM) yields of salt and no‐salt treatments and by visually scoring foliage injury. In the final trial, which involved a rescreening of the most salt tolerant species from all previous trials, 14 of the 15 entries had salt treatment DM yields which were not significantly different from no‐salt treatment yields, and five also had salt treatment foliage injury scores which were not significantly different from those of the no‐salt treatment. These five were: lemmon alkaligrass [Puccinellia lemmoni (Vasey) Scribn.]; alkali sacaton [Sporobolus airoides (Torr.) Torr.]; nuttall alkaligrass [Puccinellia airoides (Nutt.) Wats. and Coult.]; a Puccinellia roadside selection, and weeping alkaligrass [Puccinellia distans (L.) Parl.]. Entries which had no significant DM yield reduction but showed serious foliage injury were: creeping bentgrass [Agrostis stolonifera L., var. palustris (Huds.) Farw.] cv. Seaside; quackgrass [Agropyron repens (L.) Beauv.]; tall fescue (Festuca arundinacea Schreb.) cv. Alta; perennial ryegrass (Lolium perenne L.) common and cv. NK 200, creeping meadow foxtail (Alopecurus arundinaceus Poir.) cv. Garrison; redtop (Agrostis alba L.); creeping red fescue (Festuca rubra) cv. Ruby; and rough stalk bluegrass (Poa trivialis L.). Among legumes tested, alfalfa (Medicago sativa L.) cv. Vernal and sainfoin (Onobrychis viciaefolia Scop.) cv. Eski were the most salt tolerant, but both ranked lower than the better grasses. Six Kentucky bluegrass (Poa pratensis L.) cultivars were among those entries which had the greatest dry matter yield reductions and the most severe foliage injury when treated with salt.
Heritability of NaCl Tolerance in Germinating Alfalfa Seeds1
Authors: Allen S. G. , Dobrenz A. K. , Schonhorst M. H. , Stoner J. E. 
Published: July 2010

AbstractA major limitation to crop production throughout much of the world is soil salinity, which is increased by irrigation and fertilization. One way to better utilize saline soils is to grow salt tolerant crops. The objective of this research was the development of salt tolerance in germinating alfalfa (Medicago sativa L.) seeds. Five cycles of mass selection for NaCl tolerance during seed germination were conducted in the cv. Mesa‐Sirsa. Standard germination techniques were employed using blotter paper saturated with NaCl solutions of five different concentrations at a temperature of 26° C. The osmotic potential of the NaCl solution needed to produce 1% seed germination decreased from −1.40 to −2.45 MPa during the five cycles of selection. Germination at −1.30 MPa osmotic potential increased from 3% for the source population to 86% for the fifth cycle of selection. The broad sense heritability estimate for NaCl tolerance during seed germination, averaged over all cycles of selection and five levels of osmotic potential, was 50%. Significant progress was made in the development of salt tolerance in germinating alfalfa.
Germination of Basin Wildrye and Tall Wheatgrass in Relation to Osmotic and Matric Potential1
Authors: Roundy Bruce A. , Young James A. , Evans Raymond A. 
Published: July 2010

AbstractTall wheatgrass [Agropyron elongatum (Host) Beauv. ‘Jose’] and basin wildrye (Elymus cinereus Scribn. and Merr. ‘Magnar’) may have great potential for increasing the forage production of saline and arid rangelands. To determine the potential of these species to germinate and emerge in saline, arid seedbeds germination responses were studied in the laboratory in relation to decreasing medium osmotic and matric potentials, seed water contents, and seed water potentials. Tall wheatgrass had higher total germination, a higher germination rate and greater radicle growth than basin wildrye in solutions of polyethylene glycol 6000 (PEG), NaCl, Na2SO4, and CaCl2. Ion toxicity was evidenced by lower germination rates and radicle growth of both species in the salts than in PEG. Tall wheatgrass seeds were more tolerant of Na and chloride than of Ca or sulfate ions. Tall wheatgrass required less incubation days to emerge and emerged at lower soil matric potentials than basin wildrye. Both species had lower emergence in soil at reduced matric potentials than in PEG and salt solutions of equivalent osmotic potentials where seed‐soil contact and hydraulic conductivity were not limiting factors. Tall wheatgrass germinated at lower seed water contents and seed water potentials than basin wildrye. Although Jose tall wheatgrass is more likely to germinate and emerge in saline, arid seedbeds than Magnar basin wildrye, Magnar has higher germination and germinates at lower osmotic potentials than other collections of basin wildrye previously tested.
Response of Selected Soybean Cultivars to Soil Moisture Deficit1
Authors: Brown E. A. , Caviness C. E. , Brown D. A. 
Published: July 2010

AbstractExtensive research has been conducted on effects of moisture stress on growth and development of soybean [Glycine max (L.) Merr.] but information is limited on the response of determinate cultivars to moisture stress initiated at different growth stages. Moisture is a major factor limiting yield in most areas where soybeans are grown. Moisture stress experiments were conducted under field conditions using four determinate soybean cultivars of Group VI maturity, ‘Davis’, ‘Lee 74’, ‘Sohoma’, and ‘Centennial’. The experiments were conducted in 1980 and 1981 on a Captina silt loam (fine‐silty mixed, mesic Typic Fragiudult) at Fayetteville, AR. These experiments consisted of two moisture stress treatments which were initiated at the R2 and R4 growth stages and a control which was irrigated as needed throughout the season. Measurements were made on both roots and aboveground plant parts. When a moisture deficit was initiated by placing black plastic over the plots at either R2 or R4, seed yield was significantly reduced both years. A moisture deficit following application of plastic at R2 reduced yield more than at R4 in 1981, but the reverse was found in 1980, an extremely dry year. A moisture deficit initiated at R4 significantly reduced seed size and seed number both years whereas seed size was not significantly reduced either year by deficits initiated at R2. Sohoma produced significantly larger seeds than the other three cultivars when plants were moisture stressed at R4. No significant cultivar X moisture stress interactions involving seed yield were observed in either year; however, there was a definite trend for seed yields of Sohoma to be reduced less by moisture deficits initiated at stage R4 in both 1980 and 1981. Percent flower and pod shedding did not appear to be affected to any great extent by the moisture stress treatments in either year. In general, as the total number of flowers and pods increased, the number of flowers and pods shed increased proportionally. There were about four times as many roots under the row as were present in the furrow middles in both years. Also, a moisture deficit restricted root growth under the row in the upper portion of the profile, but increased it in the lower portion in the dry year of 1980.
Annual Bluegrass Growth and Quality as Influenced by Treatments of Growth Retardants and Wetting Agents1
Authors: Petrovic A. M. , White R. A. , Kligerman M. 
Published: July 2010

AbstractIt is difficult to maintain the visual quality of annual bluegrass (Poa annuaL.) during the summer because of its poor heat and drought tolerance, which could be related to the reduction of the root system and/or depletion of the carbohydrate reserves that occur during the intensive spring flowering period. Therefore, the objective of this study was to determine the effects of treatments of plant growth retardants and wetting agents on the growth and visual quality of annual bluegrass. The growth regulators mefluidide [N(2,4‐dimethyl‐5{[ (trifluoromethyl)sulfonyl]amino}phenyl) acetamide] and amidochlor {N‐[(acetylamino)methyl]2‐chloro‐N‐(2,6‐diethylphenyl) acetamide} and the wetting agents Aqua Gro (Aquatrols Corp. of America, Pennsaukin, NJ), Hydro Wet (Kalo Labs., Inc., Kansas City, MO), Basic H (Shakley Marketing Corp., Emeryville, CA), and Amway Spray Adjuvant (Amway Corp., Ada, MI) were applied prior to or at the initiation of the flowering period to annual bluegrass fairways (Dunkirk fine silt loam, fine silty, mixed mesic, Glossoboric Hapladalfs) over a 3‐yr period. Seedhead production and seed yield were reduced significantly by mefluidide, Aqua Gro, and amidochlor. The reduction ranged from 64 to 99%, 26 to 77%, and 40% for mefluidide, Aqua Gro, and amidochlor, respectively, depending on rate and timing of application and year of the study. The other wetting agents had no affect on seedhead production. Mefluidide reduced clipping yields 20% over a 2‐month period, whereas Aqua Gro had no effed. In 2 of the 3 yr of the study, mefluidide applications caused a reduction in the visual quality of annual bluegrass 14 to 24 days after treatment. Aqua Gro effects on the visual quality during the spring flowering period were inconsistent. The visual quality of annual bluegrass during the summer months, however, was not affected by the degree of spring seedhead production.
Crop Responses to Phosphorus and Potassium Fertilization of a Sodic Soil1
Authors: Chhabra R. 
Published: July 2010

AbstractUncultivated sodic soils in the Indo‐Gangetic alluvial plains of India contain high amounts of NaHCO3‐extractable P. However, the P fertilizer needs of crops grown on such soils is unknown. A longterm field experiment was conducted on a representative sodic soil (Aquic Natrustalf) with the following objectives: (i) evaluating rice (Oryza sativaL.) and wheat (Triticum aestivumL.) responses to P and K fertilization, and (ii) monitoring changes in soil‐extractable P and exchangeable K as affected by the addition of gypsum, fertilizers, and cropping. The treatments included annual application of 0 and 22 kg ha−1P as single superphosphate and 0 and 42 kg ha−1K as muriate of potash, to either wheat or to both rice and wheat grown in a rotation. In any individual year, the yields of rice and wheat were not affected by application of P and K. However, over a period of 6 yr, the mean yield of rice in control plots was lower than yields in fertilized plots. The P concentration in grain was less affected by fertilization than that of the straw. The K concentration of grain and straw of either crop was not affected. After reclamation, NaHCO3‐extractable soil P for all treatments, decreased in the first year, from 46 kg ha−1to a mean value of 22 kg ha−1. Application of 22 kg P ha−1to both crops increased the extractable soil P to 27.6 kg ha−1. In the control plot, the extractable soil P decreased each year and was reduced to 7.2 kg ha−1after 6 yr. Exchangeable K in the soil decreased in control and P fertilized plots, but the values were much above the critical limit. Apparently, in recently reclaimed sodic soils, rice and wheat may be grown without P and K fertilization for the initial 6 yr without reduction in yield.
Planting Date Effects on Seedling Development of Perennial Warm‐Season Forage Grasses. II. Seedling Growth1
Authors: Hsu F. H. , Nelson C. J. 
Published: July 2010

AbstractPerennial warm‐season forage grasses can improve animal performance in summer when cool‐season grasses become dormant and low in forage quality. Rapid establishment of acceptable stands is a factor limiting their use. Field experiments were conducted to determine optimum planting dates of perennial warm‐season forage grasses, determine effects of planting date on seedling growth and partitioning of dry matter between roots and shoots, and compare strategies of seedling growth among perennial warm‐season grasses and an annual weed. Seeds of big bluestem (BB) (Andropogon gerardiiVitman), Caucasian bluestem (CB) [Bothriochloa caucasica(Trin.) C. E. Hubb.], indiangrass (IG) [Sorghastrum nutans(L.) Nash], switchgrass (SG) (Panicum virgatumL.), and an annual species, crabgrass (CG) [Digitaria sanguinalis(L.) Scop.] were planted at approximately 2‐week intervals from early April to late June in 1982 and 1983. A split‐plot design was used with five replications. Soil was a Mexico silt loam (fine, montmorillonitic, mesic Udollic Ochraqualf). Weeds were removed by hand shortly after their emergence in 1982, while weed emergence was prevented by methyl bromide (bromomethane) treatment in 1983. All species within a given planting data were harvested when BB reached the fifth collared‐leaf stage. Crabgrass developed more leaves, had greater leaf area, and accumulated more dry matter than did perennials showing that it would exhibit strong competition to perennials during establishment. Among perennials, SG and IG developed more leaf area and accumulated more dry matter than did CB and BB. However, CB developed more leaves and tillers than did other perennials, but leaves were small. Both SG and CB had higher leaf area ratios and lower root/shoot ratios than did IG and BB. Big bluestem required fewer days to reach the fifth collared‐leaf stage on later plantings than on early plantings, but in 1982 total dry matter accumulation at the fifth leaf stage was similar among planting dates. In 1983, however, dry matter accumulation and leaf area of BB were highest when seeds were planted on 6 and 16 May. In both years the root/shoot ratio of BB was highest for early plantings and decreased as planting was delayed. Other species showed similar trends. Dry matter production averaged over planting dates for CB, IG, and SG, respectively, was 1.2, 2.5, and 2.1 times greater than BB in 1982, and 1.6, 2.6, and 3.4 times greater than BB in 1983. Perennial warm‐season forage grasses are adapted for planting between late April and mid‐May, a period when low temperatures occur to partially chill seeds and adequate soil moisture is available to allow development of the permanent root system prior to drought conditions.