bluuebunny/crossref_metadata_2025_split huggingface dataset:
Improved Nitrogen Management in Irrigated Durum Wheat Using Stem Nitrate Analysis: I. Nitrate Uptake Dynamics
Authors: Knowles T.C. , Doerge T.A. , Ottman M.J. 
Published: July 2010

AbstractIntensive N management for irrigated spring wheat (Triticum aestivum L.) grown in arid and semi‐arid regions requires preplant soil, plus periodic basal stem analyses for nitrate. Additional information on the relationships between grain yield and quality, N rates and stem nitrate‐N (NO3‐N) levels is needed for the wide range of agronomic conditions found in areas where irrigated durum wheat (Triticum turgidum L. var. durum) is grown. Five field experiments were conducted during the 1985 to 1988 crop years in southern Arizona to examine the effects of N rate, mobility of N fertilizer form, level of residual soil N, soil texture, and two contrasting wheat cultivars on basal stem NO3‐N concentrations and grain yield and quality of durum wheat. Stem NO3‐N concentrations were responsive to both fertilizer and soil‐N levels. Nitrogen applications containing mobile NO3‐N or urea‐N resulted in stem NO3‐N concentrations at the Feekes 2 growth stage (GS) that averaged 52% less (2.0 vs. 4.2 g NO3‐N kg−1) than when an equivalent amount of an immobile NH4‐N source was used on Casa Grande sandy loam [coarse, loamy, mixed (calcareous), hyperthermic, Typic Natrargid (reclaimed)] soil. Different N sources had no significant effect on stem NO3 levels for wheat grown on a Trix clay loam [fine loamy, mixed (calcareous), hyperthermic, Typic Torrifluvent] soil. Wheat grown on finer textured clay loam soils showed a two fold increase for NO3‐N accumulation in basal stem tissue due to N applications ranging from 225 to 651 kg N ha−1 over the sampling period from GS 6 through 10.5. No statistical or practical differences were observed in the quantities of NO3‐N contained in the stem tissue of two popular durum wheat cultivars (Aldura and Westbred‐881) when equivalent rates of N were applied. Visual deficiency symptoms were not observed, and subsequent grain yield and quality did not suffer when stem NO3‐N levels decreased to no lower than 1.0 g kg−1 following GS 6. These results provide important information needed to increase the precision and accuracy of the basal stem tissue NO3‐N test for predicting the N status of irrigated durum wheat.
Ionic Concentrations and Water Relations of Alfalfa Seedlings Differing in Salt Tolerance
Authors: McKimmie T. , Dobrenz A.K. 
Published: July 2010

AbstractThere is great variability within alfalfa (Medicago sativa L.) populations in response to salinity stress. This study was conducted to investigate the physiological basis of that variability. Growth performance and physiology were compared in two groups of a population of alfalfa seedlings that differ in vigor when grown under − 0.7 MPa salinity. The experiments were conducted in a greenhouse using a system designed to screen seedlings for salt tolerance. Plant height, internode length, leaf area, number of leaves, dry weight, ion concentration, percent water, and water potential were measured. Shoot parts of the more vigorous group contained lower concentrations of Na and Cl. Roots of the vigorous group contained higher Na concentrations. The vigorous group contained more total ions (Na + Cl + K) per plant but fewer total ions on a dry weight basis. Water potentials of both shoots and roots were greater in the vigorous seedling group; there were no differences in percent water.
Screening Sericea Lespedeza Germplasm for Herbage Quality
Authors: Petersen J. C. , Hill N. S. , Mosjidis J. A. , Windham W. R. 
Published: July 2010

AbstractSericea lespedeza [Lespedeza cuneata (Dumont) G. Don] is recognized as being a relatively poor quality forage because of high concentrations of tannins in its leaves. Therefore, an accurate assessment of tannins in the leaves is essential for the selection of low tannin lines. The objectives of our research were to investigate improved methods of tannin analysis for the screening of the lespedeza germplasm, and to determine the relationship between in vitro dry matter digestibility (IVDMD), crude protein (CP), and leaf tannins. Field experiments containing 81 lespedeza entries were established at two locations. Herbage samples were harvested twice during the growing season for 2 yr and the leaves analyzed for IVDMD, CP, and tannin concentration by near infrared reflectance spectroscopy (NIRS). Results of an HCI‐vanillin analysis of aqueous acetone extracts of fresh‐frozen samples (ACE‐FF) and oven‐dried samples (ACE‐OD), and methanolic extracts of oven‐dried samples (METOD) were used to derive the NIRS tannin equations. Standard errors of calibration (SEC) were lowest for the MET‐OD data and highest for the ACE‐FF data. However, coefficients of variation (CV) were inversely proportional to SEC. Coefficients of variation of field experiments were also lowest when samples were analyzed by the NIRS tannin equation derived from ACE‐FF data. Differences in tannin concentration, CP, and IVDMD existed among entries, locations, and seasons. Differences between locations and seasons were due to changes in moisture and temperature. Strong negative correlations were found for the ACE‐FF tannin data and IVDMD (r = −0.90 to −0.92), and ACE‐FF data and CP (r = −0.66 to −0.70) relationships. Our results indicate that the tannin analysis of ACE‐FF is a better reference method for NIRS calibration and subsequent screening of the lespedeza germplasm, and that the relationships between tannins, CP and IVDMD, suggest that a significant improvement in herbage quality may be achieved.
Response of Selected Forage Grasses to Herbicides
Authors: Bovey R.W. , Hussey M.A. 
Published: July 2010

AbstractEarly spring applications of herbicides were evaluated for weed control and phytotoxicity to kleingrass (Panicum coloratum L.) during establishment. In 1986, areas treated with MSMA (monosodium salt of methylarsonic acid) at 2.2 and 4.5 kg ha−1 or chlorsulfuron {2‐chloro‐N‐[ [(4‐methoxy‐6‐methyl‐1,3,5‐triazin‐2‐yl) amino] carbonyl] benzenesulfonamide} at 0.018 and 0.035 kg ha−1 reduced weed yield to <900 and increased kleingrass yield to >9300 kg ha−1. Untreated areas produced 5400 and 4300 kg ha−1 of weeds and kleingrass, respectively. In 1988, kleingrass yields were increased only where weeds were removed by hand or MSMA. Bensulide [O,Obis( 1‐methylethyl) S‐[2‐[(phenylsulfonyI) amino] ethyl] phosphorodithioate], butylate [S‐ethyl bis(2‐methylpropyl)carbamothioate], siduron [N‐(2‐methylcyclohexyl)‐N'‐phenylurea], and sulfometuron {2‐[[[[(4,6‐dimethyl‐2‐pyrimidinyl) amino] carbonyl] amino] sulfonyl] benzoic acid) were highly injurious to kleingrass. In 1989, no treatment increased kleingrass yields. In the greenhouse, ‘Selection 75’ kleingrass, common buffelgrass (Cenchrus ciliaris L.), ‘WW‐Spar’ and ‘WW‐Ironmaster’ old world bluestem [Bothriochloa ischaemum (L.) Keng var. ischaemum (Hack.) Celarier and Harlan], ‘Bell’ rhodesgrass (Chloris gayana Kunth), ‘Cowboy’ laurisiagrass (Penniseturn orientale L.), ‘Haskel’ sideoats grama [Bouteloua curtipendula (Michx.) Torr.], ‘Lameta’ Indiangrass (Sorghustrum nutans L.), 'Alamo' switchgrass (Panicum virgatum L.), and ‘Palar’ Wilman lovegrass (Eragrosfis superba Peyn.) were treated. Based on seedling weight, most grasses tolerated butylate, MSMA, 2,4‐D [(2,4‐dichlorophenoxy) acetic acid], chlorsulfuron, and metsulfuron {2‐[[[[(4 methoxy‐6‐methyl‐1,3,5‐triazin‐2‐yl)amino] carbonyl] amino] sulfonyl] benzoic acid]. Buffelgrass, Indiangrass, and old world bluestem tolerated sulfometuron. Atrazine [6‐chloro‐N‐ethyl‐N'‐(‐methylethyl)‐ 1,3,5‐triazine‐2,4‐diamine] and propazine [6‐chloro‐N,N'‐ bis(l‐methylethyl)‐l,3,5‐triazine‐2,4diamine] were sometimes injurious, but bensulide and siduron were highly injurious to most grasses.
Functions of Crop Yield from Applied Water
Authors: Helweg Otto J. 
Published: July 2010

AbstractAlthough there is no unique crop water production function (yield vs. applied water), curves of general functional relationships have utility and are commonly presented in the literature. Some crop production functions used in research and practice are assumed to be linear. Other functions are assumed to be quadratic, or less frequently some other non‐linear form. Though these functions may be adequate for the purpose for which they are used, they do not always produce a realistic shape. As the need to know and display the correct shape of the function becomes greater, an improved mathematical expression of the function is required. The criteria of a desirable production function includes being robust as well as accurately fitting the data. Evaluation of several popular functions showed that the Meixner functional series accurately modeled the water‐yield relationship of wheat (Triticum aestivum L.) from an experimental plot in Saudi Arabia.
Modeling Lamb Weight Changes on Wheatgrass and Wheatgrass‐Sainfoin Mixtures
Authors: Karnezos T.P. , Matches A.G. 
Published: July 2010

AbstractPrediction of animal weight change (CUM) with regression models developed from grazing trials typically uses herbage parameters and CUM measured on the same day. We hypothesized that lamb (Ovis aries L.) CUM recorded at time t was a function of herbage quality and/or quantity measured at a previous harvest t − x (where x = days prior to measurement of CUM). Our objectives were (i) to determine if time series regression analysis (TSR) could be used to model CUM from three irrigated wheatgrasses, ‘Hycrest’ [Agropyron cristatum (L.) Gaertner × A. desertorum (Fischer ex Link) Shulters], ‘Luna’ [Thinopyrum intermedium subsp. barbulatum (Schur) Barkw. and D.R. Dewey], and ‘Jose’ [T. ponticum (Podp.) Barkw. and D.R. Dewey] grown alone and with ‘Renumex’ sainfoin (Onobrychis viciifolia Scop.), and (ii) to test the models. Replicated pastures grown on a fine, mixed thermic Torrertic Paleustolls were rotationally grazed by Rambouillet × Suffolk wether lambs for an average of 77 d in spring of 1987 and 1988. Herbage quality, quantity, and plant parts were estimated from pregrazing, after 2 and 4 d of grazing, and postgrazing (7 d) harvests and used as variables in TSR. For TSR models, lagged variables (t − x) were selected more (67–92% of total) than nonlagged variables (t), supporting our hypothesis. Time series regression models described CUM accurately (average R2 > 0.70), but selected variables were not consistent among treatments, time lags, or years. Model testing indicated poor predictive accuracy (r2 = 0.07−0.51), limiting the usefulness of projecting CUM across seasons and demonstrating the necessity of testing regression models.
Florigraze Rhizoma Peanut in Association with Warm‐Season Perennial Grasses
Authors: Dunavin L. S. 
Published: July 2010

AbstractThe rhizoma peanut (Arachis glabrata Benth.), a warm‐season perennial legume, offers enough promise to justify investigating its potential as a companion legume with various adapted perennial grasses. A field experiment was conducted on an Orangeburg sandy loam (fineloamy, siliceous, thermic Typic Paleudults) near Jay, FL, to determine the efficacy of using ‘Florigraze’ rhizoma peanut with ‘Tifton 44’ bermudagrass [Cynodon dactydon (L.) Pers.], ‘Floralta‘ limpograss [Hemarthria altissima (Poir.) Stapf and C. E. Hubb], and ‘Pensacola’ bahiagrass (Paspalum notatum Flugge) from 1981 through 1988. Volunteer grasses replaced Floralta in 1985 through 1988, and cool‐season forage crops, ‘Wrens abruzzi’ rye (Secale cereale L.), ‘Fla. 80’ ryegrass (Lolium multiflorum Lam.), and ‘Dixie’ crimson clover (Trifolium incarnatum L) were then seeded over the peanut‐grass plots in the fall. Dry matter (DM), crude protein (CP), and digestible organic matter (DOM) production of the combined grass and legume forage were determined. During the first 4 yr, the yields of DM, CP, and DOM from each grass‐peanut mixture were essentially equal; however, more DM and DOM were produced by limpograss‐peanut in 1981 and 1982. In the last 4 yr, the volunteer grass‐peanut generally produced the least DM, and less DOM, in 1986 and 1987. The peanut content decreased during the last 4 yr in all mixtures but most markedly in the bahiagrass‐peanut mixture. In general cool‐season crops performed best when seeded over bermudagrass‐peanut followed by performance over volunteer grass‐peanut and bahiagrass‐peanut, respectively. Rhizoma peanut can be successfully grown with various perennial grasses for several years but may eventually be crowded out by such thick‐sodded grasses as Pensacola bahiagrass.
Early Season Floral Bud Removal and Cotton Growth, Yield, and Fiber Quality
Authors: Pettigrew W.T. , Heitholt J.J. , Meredith W.R. 
Published: July 2010

AbstractCotton (Gossypium hirsutum L.) has a capacity to partially compensate for the loss of floral buds (squares). A 2‐yr (1989 and 1990) field study was conducted to determine how growth, yield, and fiber quality traits of different genotypes were affected by early season square removal. Early developing squares were removed by hand, or were induced to abscise by ethephon [(2‐chloroethyl)phosphonic acid] application. Genotypes used were ‘DPL 50’, a normal leaf type, and three leaf type isolines of ‘MD 65–11’ (normal, okra, and super okra). Compared to the check, the ethephon application decreased plant height by as much as 11% early after application, but the treated plants ultimately exceeded the check by 5% in height, in 1990. The seasonal maximum vegetative dry weight and leaf area index (LAI) did not differ between treatments either year, though the ethephon treatment did increase mainstem node number to 26, compared to 24 nodes for the check. Lint yields did not differ between treatments in 1989, but the ethephon treatment yielded 7% less than the check in 1990. Ethephon application reduced boll size 7% each year, compared to the check. Fiber quality traits were not affected by treatments in 1989, but in 1990 micronaire, maturity, and cell wall thickness were decreased by 6% on fiber from the ethephon plots as compared to the check. This study demonstrated that cotton has potential to compensate for early square loss but did not suggest that early square removal consistently leads to improved yields or fiber quality.
Nitrogen Fertilizer Recovery by Soybean in Monoculture and Rotation Systems
Authors: Varvel G. E. , Peterson Todd Andrews 
Published: July 2010

AbstractCrop rotations including soybean [Glycine max (L.) Merr.] have increased in importance because of their potential to increase yields, reduce expenditures for pesticides and fertilizer, and increase net returns to the producer. Despite the importance of soybean in the USA, there is a lack of understanding of how N affects soybean in rotation systems. This study was conducted to determine the effects of rotation and N fertilization on N uptake and recovery by soybean. Soybean was grown under rainfed conditions on a Sharpsburg silty clay loam (fine, montmorillonitic, mesic, Typic Argiudoll) in five cropping systems: (i) continuous soybean monoculture, (ii) a 2‐yr corn (Zea mays L.)‐soybean rotation, (iii) a 2‐yr grain sorghum [sorghum bicolor (L.) Moench]‐soybean rotation, (iv) a 4‐yr rotation of corn‐oat [Avena sativa (L.)] + clover [80% Melilotus officinalis (L.) and 20% Trifolium pratense]‐grain sorghum‐soybean, and (v) a 4‐yr rotation of grain sorghum‐oat + clover‐corn‐soybean at Mead, NE. Broadcast applications of 15N‐depleted NH4NO3 were made at 34 and 68 kg N ha−1 in 1985 and 1986 to evaluate N fertilizer recovery by soybean in each cropping system. Nitrogen recovery determined by isotope analyses was approximately 50% in all rotation systems and was not significantly affected by rotation or N rate. Large amounts of N were removed by the harvested soybean seed in all systems (150 to 200 kg N ha−1), regardless of N fertilizer applications. Soybean can act as a N sink and potentially aid in reducing the amount of soil N available for leaching. Since soybean grown in a rotation can utilize soil or fertilizer N along with the other benefits of rotations, soybean shows promise as a crop that may help reduce the leaching of nitrate‐N in to ground water.
Conservative Response and Stress‐Damage Interactions in Cotton Reproductive Development
Authors: Ungar E.D. , Kletter E. , Genizi A. 
Published: July 2010

AbstractIncreasing costs of inputs in upland cotton (Gossypium hirsutum L.) have highlighted the need for more sophisticated within‐season management of the crop. The objective of this study was to investigate the interaction between the timing of water stress and simulated pest damage in their effects on cotton yield and yield components. A field experiment was repeated throughout 5 yr on a Gan Shmuel vertisol (clayey, montmorillonitic, calcareous, thermic Typic Chromoxerert). Treatments comprised a control [post‐emergence irrigations at first flower (f), f+23, and f+38 d]; a delay in this sequence from the first (f+ 8, f+ 33, and f+ 47 d), second (f, f+ 32, and f+ 46 d), or third irrigation (f,f+23, and f+48 d); four irrigations (f−9,f+ 12,f+ 27, and f+ 40 d); and severe mid‐season stress (f−10, f+ 23, and f+38 d). Total irrigation amount was constant. The dates of the six irrigation schedules were repeated with pest damage simulated by the early removal of 120 floral buds meter−2. There was a significant stress‐damage interaction in flower, boll, and fiber production. In comparison with the undamaged control, boll production was reduced by damage alone and by stress alone. All stress‐damage combinations, however, restored boll production to the control level. Only severe mid‐season stress without damage, reduced seed cotton yield. Treatment effects were detected despite an underlying conservatism in crop response, whereby flower retention was inversely related to flower production. This resulted in low variability of boll number. The effect of boll number on yield was in turn buffered by boll weight. Consequently, irrigation scheduling and the control of pests that damage fruiting bodies cannot be optimized independently.
Nitrogen Release from Crimson Clover in Relation to Plant Growth Stage and Composition
Authors: Ranells N. N. , Wagger M. G. 
Published: July 2010

AbstractIncreased N‐use efficency and economic savings may result from a better understanding of N release patterns from legume residues. A 2‐yr field experiment was conducted on a Cecil fine sandy loam (clayey, kaolintic, thermic Typic Kanhapludult) to examine the effects of crimsom clover (Trifolium incarnatum L.) growth stage on dry matter accumulation, N concentration, and chemical composition in relation to N release under no‐tillage management. Crimson clover was harvested in the spring at four growth stages (late vegetative, early bloom, late bloom, and early seed set). Air‐dried plant material in 1‐mm mesh nylon bags was placed on the soil surface; retreived at 1−, 2−, 4−, 8−, and 16‐wk intervals; and analyzed for total N, C, cellulose, hemicellulose, and lignin concentrations. Averaged over 2 yr, dry matter production increased from 2.3 to 5.6 Mg ha−1, and N concentration declined from 30.2 to 21.2 g kg−1 as crimson clover matured from late vegetative to early seed set growth stages. Cellulose concentration increased by 66%, hemicellulose by 37%, and lignin by 87% from late vegetative to early seed set. Estimated clover N release at the 8‐wk retrieval was 28, 40, 40, and 54 kg ha−1 in 1989 and 51, 67, 73, and 55 kg ha−1 in 1990 for the late vegetative, early bloom, late bloom, and early seed set growth stages, respectively. Results indicated that allowing crimson clover to attain the late bloom stage prior to desiccation and planting of the summer crop can maximize clover top‐growth N content and subsequent N release.
Environment, Cultivar, and Ethephon Rate Interactions in Barley
Authors: Stobbe E. H. , Moes J. , Bahry R. W. , Visser R. , Iverson A. 
Published: July 2010

AbstractEthephon[(2‐chloroethyl)phosphonic acid] reduces barley (Hordeum vulgare L.) plant height and lodging potential, but variable effects on yield components and yield also have been reported, depending on ethephon rate, cultivar, and environment. This study was conducted to investigate environment– and cultivar–by‐ethephon‐rate interactions for barley grown under Manitoba conditions. ‘Argyle’, ‘Bedford’, and ‘Samson’ barley were sown on each of two dates in 1986 and 1987, and on single dates in 1988 and 1989, at Portage la Prairie, MB on Neuhorst clay loam (fine‐loamy, frigid aquic Haploboroll). Ethephon was applied at Zadoks GS45‐47 at 0, 120, 240, 360, or 480 g ha−1. Plant height, Belgian lodging index, yield components, and yield were determined at maturity. Plant height reductions due to ethephon were unaffected by environment, and the percentage height reduction was described as a quadratic function of ethephon rate with higher increments of ethephon producing smaller increments of height reduction. Lodging only occurred in 1986, and ethephon at 240 g ha−1 eliminated lodging in most cases. Environment‐by‐cultivar‐by‐ethephon treatment interactions are significant for grain yield, spikes per square meter, and kernels per spike. Grain yield was not consistently affected by ethephon. Spikes per square meter sometimes increased, but was more often unaffected by ethephon. Kernels per spike was often reduced by ethephon. Kernel mass decreased with increasing rates of ethephon for Argyle and Bedford, but remained stable for Samson. Grain yield increased for Argyle and Bedford in cases where ethephon reduced lodging and increased spikes per square meter. Grain yield tended to decrease in cases where lodging was not a factor and ethephon reduced kernels per spike and/or kernel mass. Year‐to‐year variation in rainfall amount and distribution, and temperature may explain some of the observations made. In Manitoba, a maximum rate of 240 g ha−1 of ethephon should be used only in cases where the risk of severe lodging is high.
Soybean Growth and Development Alterations caused by Helicoverpa zea (Boddie) Feeding
Authors: Eckel Craig S. , Bradley J.R. , Van Duyn John W. 
Published: July 2010

AbstractCorn earworm, Helicoverpa zea (Boddie), injury to soybean, Glycine max (L.) Merr, is characterized primarily by feeding on leaves, pods, and flowers. Although soybean can withstand considerable damage to each plant part individually or in combination without yield loss, corn earworm larvae frequently cause yield reductions. To evaluate alterations in plant growth that determine if yield losses occur, the plant growth and yield response of soybean to corn earworm injury was observed at six experimental sites from 1985 to 1987. Insecticides were used to either promote or suppress corn earworm populations, and population levels were monitored during the period of infestation with ground‐cloth samples. The effect of corn earworm feeding on leaf area index, number of flowers, number of pods, and pod weight was monitored weekly from the time of infestation until harvest. Leaf area index was reduced at each site. Flower and pod feeding resulted in a delay in pod fill and a reduction in final pod number at several sites. The rate of pod fill was increased in treatments with large corn earworm populations at two sites and was decreased at one site. The number of seeds per pod was also reduced by corn earworm feeding at several sites; the weight per pod was decreased at one site and increased at other sites. At harvest, the seed number, weight per seed, percent oil and protein, and harvestable yield were sampled. Yields were reduced at all but one site, and losses were attributed primarily to reduction in pod and seed number. At one site where infestation occurred during the early flowering stage, yield loss was attributed primarily to reduced weight per seed. Since mechanisms of yield reduction were different, different thresholds may be required for soybean in early reproductive stages and soybeans in later stages.