bluuebunny/crossref_metadata_2025_split huggingface dataset:
Development of Diagnosis and Recommendation Integrated System Norms for Bahiagrass
Authors: Payne G. G. , Rechcigl J. E. , Stephenson R. J. 
Published: July 2010

AbstractBahiagrass (Paspalum notatum Flugge) is grown on more pasture land in Florida than all other pasture‐grasses combined. Despite the large amount of bahiagrass grown annually, there is a surprising lack of information concerning the nutrient requirements of bahiagrass‐pastures. Currently, fertilizer recommendations for all nutrients, especially micronutrients. The Diagnosis and Recommendation Integrated System (DRIS) was developed to make an interpretation from the results of the chemical analysis of a plant tissue sample from which an accurate fertilizer recommendation could be made. The DRIS represents a holistic approach to interpreting tissue analyses. This study was conducted to develop DRIS norms for bahiagrass‐pastures and to evaluate the accuracy of those norms. A database, from which the DRIS norms were determined, was assembled by collecting 857 bahiagrass‐pasture samples from ongoing bahiagrass field fertility trials located in nine counties throughout central Florida and analyzing the samples for N, P, K, Ca, Mg, Fe, Mn, Zn, and Cu. At the time of sampling, forage yields were also determined. When DRIS norms were applied to data from an independent study in which bahiagrass was grown in greenhouse solution culture, known nutrient deficiencies were accurately diagnosed. The nutrients limiting bahiagrass forage yields in a fertility trial conducted under field conditions were also correctly identified by the DRIS interpretation of the tissue analyses. The results obtained during this study indicate that the DRIS can be successfully applied to bahiagrass grown and sampled under a wide range of conditions. Therefore, it appears that the DRIS developed for bahiagrass can provide very useful information from which nutrient deficiencies can be readily and correctly identified and more accurate fertilization programs can be developed for bahiagrass‐pastures.
Yield and Regrowth Characteristics of Alfalfa Grazed by Steers during Spring and Summer
Authors: Wolf D. D. , Allen V. G. 
Published: July 2010

AbstractCurrent recommendations for grazing alfalfa (Medicago sativa L.) include grazing for a few hours or days when plants are near a haycut stage. This study investigated the influence of continuous grazing of ‘Arc’ alfalfa by steers (Bos taurus L.) during spring (38 d), summer (26 d), or both on plant growth, potato leafhopper (Empoasca fabae Harris) population, and subsequent hay yields. Three grazing and one nongrazed treatments were imposed during 1986 and 1987 on Groseclose silt loam (clayey, mixed, mesic Typic Hapludults). Treatments included: (i) spring grazing started when alfalfa height was approximately 10 cm, followed by three hay harvests; (ii) hay harvested twice, followed by summer grazing that started when alfalfa height was approximately 15 cm, followed by one hay harvest; (iii) both spring and summer grazing as described above with hay harvested after the second and fourth growth cycles; and (iv) nongrazed with hay harvested four times. No grazing was imposed during 1988 when hay was harvested four times to measure the influence of previous grazing. In 1986 and 1987, hay yields following spring grazing (6.61 Mg ha−1) were not different than those for nongrazed (6.47 Mg ha−1). Fall hay yields following summer grazing (1.39 Mg ha−1) and spring plus summer grazing (1.34 Mg ha−1) treatments were lower than for spring grazing (1.85 Mg ha−1) or nongrazed treatments (1.80 Mg ha−1). Grazing had no influence on root total nonstructural carbohydrates at the end of Year 2. Grazing for 2 yr by any treatment had no effect on yields during Year 3 when alfalfa was harvested four times for hay. Potato leafhopper density increased during regrowth following summer grazing to a level of 11.5 insects per sweep that required insect control, whereas little buildup occurred following hay harvest during the same growth period. Our data show that grazing, begun in spring or summer at a young vegetative stage, can continue for a time equal to a growth cycle in either or both seasons of at least 2 yr with no detrimental effect on alfalfa hay yield in Year 3.
Nitrogen Effects on Yield and Malting Quality of Barley Genotypes under No‐Till
Authors: Clancy J.A. , Tillman B.A. , Pan W.L. , Ullrich S.E. 
Published: July 2010

AbstractConservation practices, such as reduced tillage and improved fertilizer use, are desirable from an environmental perspective and may yield economic benefits if production and quality are not impaired. This study was conducted to determine the effects of two N fertilization levels, 45 and 90 kg ha−1 (50 and 100% of normal grower rates), on yield and malting quality of spring barley (Hordeum vulgare L.) under no‐till management. The study was conducted in 1986 and 1987 on a Palouse silt loam (fine‐silty, mixed mesic Pachic Ultic Haploxeroll). Seven Nordic (Europe) genotypes were compared with four U.S. Pacific Northwest (PNW) cultivars. The higher N level increased grain yield across genotypes in both years (17% in 1986, 5% in 1987), reduced the percentage of plump kernels (4%) in 1987, and did not affect test weight, 1000‐kernel weight, or percentage of thin kernels. All Nordic genotypes yielded less than the PNW cultivars except the Danish cultivar Nordal. Higher N increased total malt protein (7%) in both years and soluble malt protein (7%) in 1986. Higher N also significantly increased a‐amylase (25%) and diastatic power (15%) in the malt, while malt extract was unaffected. Significant genotypic differences existed for all agronomic and malting parameters examined. Under no‐till, HJA 78003 was the only Nordic genotype that produced good quality malt, equaling the three PNW malting cutlivars under no‐till. The higher N rate produced slightly better yield and quality than the reduced rate. Therefore, reducing the N rate to half the normal grower rate (90‐45 kg ha−1) would probably not be recommended under these test conditions. Overall, the PNW cultivars tested outperformed the Nordic genotypes both in yield and malting quality. However, Nordal and HJA 78003 could prove useful in PNW barley breeding programs.
Improved Nitrogen Management in Irrigated Durum Wheat Using Stem Nitrate Analysis: II. Interpretation of Nitrate‐Nitrogen Concentrations
Authors: Knowles T.C. , Doerge T.A. , Ottman M.J. 
Published: July 2010

AbstractAttempts to characterize the N status of irrigated spring wheat (Triticum aestivum L.) using basal stem nitrate‐N (NO3‐N) tissue tests have shown contradictory results due to the narrow range of agronomic conditions existing in most studies. Five field experiments were conducted in southern Arizona to examine the effects of N rate, mobility of N fertilizer form, residual soil N, soil texture, and two contrasting cultivars on basal stem NO3‐N concentrations, yield and quality of irrigated durum wheat (Triticum turgidum L. var. durum). Fertilizer N treatments were broadcast at planting, then at Feekes 5,10, and 10.5 growth stages (GS) to simulate fertilization in conjunction with the first four basin irrigation events. Stem tissue samples were taken from all plots at GS 2, 5, 6, 10, and 10.5 for NO3‐N analysis. A critical level of 2000 mg NO3‐N kg−1 in durum wheat stem tissue at GS 2 through 5 was suggested. Critical wheat stem tissue NO3‐N concentrations of 1000 mg kg−1 at GS 6 through 10 and 500 mg kg−1 at GS 10.5 were also defined. Significant grain yield reductions due to excessive N fertilizer applications resulted when stem tissue NO3‐N concentrations exceeded 6000,5000,4000, 3000, and 2000 mg kg−1 at GS 2, 5, 6, 10, and 10.5, respectively. Optimum durum wheat grain yield and quality occurred when basal stem tissue NO3‐N concentrations ranged from 3000 to 4000, 2500 to 3500,1000 to 1500,500 to 1000, and 200 to 500 mg kg−1 at GS 2,5,6, 10, and 10.5, respectively. These results should prove useful in predicting the N needs of irrigated durum wheat grown under arid and semi‐arid conditions.
Sward Dynamics and Herbage Nutritional Value of Alfalfa‐Ryegrass Mixtures
Authors: Jung G. A. , Shaffer J. A. , Rosenberger J. L. 
Published: July 2010

AbstractNo grass species has proven to be well suited as a companion grass in binary mixtures with alfalfa, Medicago sativa L., over a wide range of environments and management practices. Two trials were conducted with alfalfa and perennial ryegrass, Lolium perenne L., as binary mixtures and monocultures in Pennsylvania, USA (41 °N, 77 ° 30'W) to determine the influence of seeding rate and phenological development and tillering potential of ryegrass on sward dynamics and herbage nutritional value. The experiment was seeded on Hagerstown silt loam (fine, mixed, mesic Typic Hapludalfs) soil in August 1983 and 1984 to determine consistency of sward dynamics of stands seeded in different years. Field plots were harvested in late May and after 35‐d intervals in summer, and 45 d in fall. Near infrared reflectance spectroscopy was used to estimate botanical composition of the mixtures. Nitrogen concentration and in vitro dry matter disappearance determinations were made on freeze‐dried herbage for 2 yr from one of the two trials. Botanical composition of alfalfa‐perennial ryegrass mixtures was influenced more by ryegrass seeding rate than by alfalfa seeding rate. The influence of alfalfa and ryegrass seeding rates on botanical composition was particularly large during stand establishment and the first crop year. Alfalfa became the dominant species within 1 yr in all mixtures in both trials even when conditions heavily favored ryegrass during stand establishment. Annual yield of digestible dry matter was maximized at 9.9 Mg ha−1 when alfalfa and perennial ryegrass were seeded at approximately 15 and 11 kg ha−1, respectively. Weed content of the mixtures was inversely related to seeding rate of ryegrass.
Yield and Nitrogen Fixation of Chickpea Cultivars in Response to Inoculation with Selected Rhizobial Strains
Authors: Beck D. P. 
Published: July 2010

AbstractWith development of new cultivars for winter sowing, production of Kabuli chickpea (Cicer arietinum L.) has expanded into drier areas of the Mediterranean region where low or less effective populations of indigenous rhizobia may limit N2 fixation. This study was conducted to quantify field N2 fixation using 15N for eight chickpea cultivars as affected by native rhizobial populations and three introduced rhizobial strains, and to determine the extent of strain‐cultivar interactions for N2 fixation and yield. Host‐by‐strain interactions for N2 fixation were highly significant in a greenhouse experiment utilizing a N‐free aseptic hydroponic system. Inoculation significantly increased total above ground dry matter (AGDM) and seed yields over uninoculated control in field trials conducted at two locations at Tel Hadya, Syria, on a Vertic Chromoxeralf soil during two seasons (1987–1989). All yield and N2 fixation parameters differed significantly among chickpea cultivars and rhizobial strains in the wetter (1987–1988) season where cultivar‐strain interactions were significant for seed yield, N yield, and N2 fixation; differences in N yield and N2 fixation were not significant in the drier season. Average quantities of N2 fixed were 68 and 27 kg N ha−1 in inoculated treatments for 1987–1988 and 1988–1989 trials, respectively. Inoculation with the best strain treatment in 1987–1988 increased the average proportion of N derived from fixation (%Ndfa) from 52% to 72%; maximum %Ndfa for this trial was 81%. Maximum %Ndfa was 67% in the 1988–1989 trial. Significant strain‐by‐cultivar interactions and the yield response to selected rhizobial strains suggest an important role for field inoculation of chickpea for increased N2 fixation.
Early Planted, Early Maturing Soybean Cropping System: Growth, Development, and Yield
Authors: Kane M. V. , Grabau L. J. 
Published: July 2010

AbstractAn early planted, early maturing soybean [Glycine mar (L.) Merr.] cropping system could stagger harvest maturity and increase the number of options available for subsequent crops. However, premature flowering of early maturing cultivars could reduce canopy closure at flowering (CCR1) or at beginning seed fill (CCR5) as well as vegetative mass at R5 (VMR5). This study was conducted to determine the Maturity Group (MG) best suited for this early planted cropping system, and to relate growth, development, and environmental parameters to yield. Two cultivars each from MG 00,0,I,II,III, and IV were planted in six Kentucky field environments ranging from 36°40' to 38°7'N lat from 1986 to 1989. Vegetative, pod‐set, and seed‐fill durations were generally shorter in early‐maturing cultivars, but also interacted with environment. Maturity groups 00 and 0 had inadequate canopy closure at R1 and R5, inadequate vegetative mass at R5, and produced lowest overall yields. While MG I and II appeared to be most sensitive to vegetative and pod‐set rainfall and seed‐fill temperatures, MG II produced the best mean yield. Seed‐fill duration and rainfall were apparently more important for MG III and IV than for earlier MGs. Maturity Group II appears to be more adaptable than other MGs in these early planted, early maturing soybean cropping systems in Kentucky.
Rhizome Characteristics and Canopy Light Interception of Grazed Rhizoma Peanut Pastures
Authors: Ortega‐S. J. A. , Sollenberger L.E. , Bennett J.M. , Cornell J.A. 
Published: July 2010

Abstract‘Florigraze’ rhizoma peanut (Arachis glabrata Benth.) is a promising pasture legume for warm climates. In 1988 and 1989, the effect of grazing management on rhizoma peanut canopy light interception (LI) and the role of rhizome reserves in regrowth were studied on a Sparr fine sand (loamy, siliceous, hyperthermic Grossarenic Paleudults). Treatments were replicated twice and included all combinations of three levels of residual dry matter (RDM; 500, 1500, and 2500 kg ha−1) and four grazing cycle lengths (GC; 7, 21, 42, and 63 d between grazings, including a 0.5 to 2‐d grazing period). Data were analyzed by fitting multiple regression equations starting with a second order polynomial model. Canopy LI before grazing ranged from 24 to more than 90% and was lowest for low RDM and short GC treatments, while canopy LI after grazing ranged from 9 to 79% and increased at a decreasing rate as RDM increased. When grazed to 500, 1500, and 2500 kg ha−1, RP required an average of 49, 24, and 12 d to reach 85% LI. At season‐end 1989, rhizome mass (range of 450‐4100 kg ha−1) and total nonstructural carbohydrate (TNC; range of 58‐210 g kg−) concentration were lowest at low RDM and short GC, increased with increasing GC when RDM was low, and changed only slightly with changes in GC at RDM above 1700 kg ha−1. Low postgraze light interception and depletion of rhizome mass and total nonstructural carbohydrate with close grazing suggest that reserves were mobilized for rhizoma peanut regrowth. In contrast, postgraze light interception and rhizome mass and reserve status remained high when residual dry matter was 1700 kg ha−1 or greater suggesting that residual leaf area was primarily responsible for regrowth under more lenient grazing.
Development of Soybean Fresh and Dry Weight Relationships for Real Time Model Calibration
Authors: Kenig A. , Mishoe J. W. , Boote K. J. , Cook P. W. , Reicosky D. C. , Pettigrew W. T. , Hodges H. F. 
Published: July 2010

AbstractMeasurements of dry weight and crop phenology are normally used to validate comprehensive growth models. To reduce this requirement in applications such as large area yield forecasting, the present research was conducted to study the change of dry matter concentration (ratio of dry weight to fresh weight) of the vegetative and reproductive plant components of soybean (Glycine max (L.) Merr.]. The paper evaluates the usefulness of simple statistical equations that relate dry matter concentration to developmental stages for the specific purpose of growth model calibration. During the 1984 through 1985 seasons, five cultivars of soybean were grown in five locations throughout the soybean producing regions of the U.S. Soil type, planting date, plant population, and irrigation management varied from site to site. Plant samples were taken at 1‐ to 2‐wk intervals during the growing season for fresh weight and dry weight of vegetative parts and pods, and counts of reproductive sites. In most of the field locations, dry matter concentration of different soybean parts was found to follow a predictable pattern. The pattern was explained for most locations by a simple relation of developmental stage and vegetative dry matter concentration, using data collected until the beginning of pod fill. A second model explained the course of pod dry matter concentration over developmental stage, using data collected after the beginning of seed growth. Insignificant differences among regression lines of extreme locations suggest that the course of dry matter concentration may be of an inherent nature, with minor impact due to differences of cultivar, or weather. The equations developed in this paper to estimate dry weight data will reduce the effort of calibrating and/or validating soybean comprehensive growth models by requiring only the collection of fresh weight samples at known phenological events.
Frequency of Plant Growth Regulator and Mowing Treatments: Effects on Injury and Suppression of Centipedegrass
Authors: Johnson B. Jack. 
Published: July 2010

AbstractCentipedegrass [Eremochloa ophiuroides (Munro) Hack.] is a popular low maintenance turfgrass that produces seedheads from midsummer until early fall, Since regular mowing is needed to maintain a quality turf, experiments on rate and frequency of plant growth regulator applications and mowing frequencies were initiated to assess their effect on suppression of vegetative and reproductive growth of centipedegrass. Various rates of imazethapyr {2‐[4,5‐dihydro‐4‐methyl‐4‐(1‐methylethyl‐5‐oxo‐1H‐imidazol‐2‐yl]‐5‐ethyl‐3‐pyridinecarboxylic acid}, mefluidide {N‐[2,4‐dimethyl‐5‐[[(trifluoromethyl)sulfonyl]amino]phenyl]‐acetamide}, and CGA 163935 [4(cyclopropyl)‐α‐hydroxy‐methylene)‐3,5‐dioxocyclohexanecarboxylic acid ethylester] were evaluated as sequential applications and in combination with mowing on suppression of centipedegrass. Imazethapyr applied initially at 0.3 kg ha−1 and then followed by 0.15 kg ha−1 4‐wk later suppressed a higher percentage of centipedegrass seedheads without causing undesirable injury than when the second application was made at a 2‐or 3‐wk interval. Seedhead suppression was similar when imazethapyr was applied at 0.3 kg ha−1 and then followed by two mowings (6 + 8 wk) in 1990 and one mowing (6 wk) in 1991. Mefluidide applied initially at 0.6 kg ha−1 and followed by 0.6 kg ha−1 2‐wk later injured centipedegrass less than when the second application was made at a 3‐ or 4‐wk interval. Seedhead suppression was not consistent each year regardless of the time of the second mefluidide application. However, seedhead suppression was acceptable for 10 wk when mefluidide was applied to 0.6 kg ha−1 and followed by two mowings (4 + 7 wk) in 1990 and three mowings (2 + 4 + 8 wk) in 1991, or when 0.6 kg ha−1 was followed by 0.3 kg ha−1 and one mowing at 6 wk in 1990 and 2 wk in 1991. CGA 163935 injured centipedegrass more and suppressed seedheads less than either imazethapyr or mefluidide.
Nutrient Accumulation and Removal by Sugarcane Grown on Everglades Histosols
Authors: Coale F. J. , Sanchez C. A. , Izuno F. T. , Bottcher A. B. 
Published: July 2010

AbstractSugarcane (interspecific hybrids of Saccharum spp.) is Florida's most valuable agronomic crop. Recently, sugarcane production has come under scrutiny because of concerns regarding the impact of nutrient‐rich drainage water on the ecology of adjoining bodies of water and wetlands. The objective of our research was to define the N, P, K, Ca, and Mg seasonal accumulation patterns in the aerial portion of sugarcane grown on organic soils of the Everglades Agricultural Area. Sugarcane fields were sampled on 30 to 60 d intervals during the plant‐cane and first‐ratoon crops. Dry weight, N, P, K, Ca, and Mg accumulation were determined and characterized by logistic growth models. Dry weight accumulation averaged 0.15 t ha−1 d−1 during the grand growth period. The period of most rapid nutrient uptake was shown to correspond with the grand growth period and the rates of nutrient uptake during different phases of crop development were defined. At harvest, 71% of total dry matter and 55, 63, 64, 25, and 38% of total accumulated N, P, K, Ca, and Mg, respectively, were removed from the field as millable sugarcane. Phosphorus and K removal from the field by crop harvest was equivalent to 179 and 201%, respectively, of added fertilizer P and K. Apparently, fertilizer P and K were minor contributors to the total soil pool of plant available P and K. Nutrient accumulation patterns should be incorporated into future management plans designed to minimize the impact of sugarcane production on the surrounding environment.
Predicting Grain Sorghum Canopy Structure for Soil Erosion Modeling
Authors: Armbrust D. V. , Bilbro J. D. 
Published: July 2010

AbstractDevelopment of modern water and wind erosion prediction technology requires information on the canopy structure of various plant species to accurately predict the canopy effect on the falling raindrop or the erosive force of the wind. The objective of this study was to develop equations to predict grain sorghum [Sorghum bicolor (L.) Moench] canopy structure characteristics. Grain sorghum plants were sampled weekly from emergence to maturity at Big Spring, TX (1986–1987), and Manhattan, KS (1987), to measure the following crop canopy parameters: plant height, stem length, leaf area, stem area, and canopy cover. Manhattan data were used to develop equations that relate canopy structure parameters of grain sorghum to the total above‐groundry weight, and Big Spring data were used to validate those equations. Leaf and stem area distributions with height also were determined. Coefficients of determination of predicted values using the Manhattan equations and Big Spring above‐ground dry weight and the measured Big Spring data ranged from 0.987 for leaf area to 0.922 for stem length. Distribution of leaf and stem area with height remained essentially constant with plant age through the first 7 wk after planting. The equations can be used to supply canopy structure information needed by wind and water erosion prediction models currently under development.