bluuebunny/crossref_metadata_2025_split huggingface dataset:
Corn Motion in the Wind during Senescence: II. Effect of Dynamic Plant Characteristics
Authors: Flesch T.K. , Grant R.H. 
Published: July 2010

AbstractLodging in corn (Zea mays L.) is often the result of wind‐induced motion, which creates a strain on the stalk and root system. In elastic theory, motion is defined by static characteristics (stiffness) and dynamic characteristics (damping coefficient [ζ] and natural frequency [fn]). A study was conducted to determine the relationship of plant ζ, fn, and stiffness (K) to total plant motion in the wind. The ζ,fn and K were calculated from stalk motion measured on 23 plants in the field during October, 1988, at West Lafayette, IN. Interrow contact was eliminated, and plants were grouped according to whether the ear was upright or had fallen to a hanging position. With the ear upright, ζ,fn, and K averaged 0.11, 1.54 Hz, and 2.44 N m deg−, respectively. Plant resonant oscillations corresponded with fn. The fn was well above the frequencies of highest wind energy. In theory, total plant motion will decrease as ζ and fn, increase. Field measurements showed that with the ear upright, and fn were uncorrelated with total motion, but when the ear dropped to a hanging position, there was a 54% increase in ζ accompanied by by a 15% reduction in motion. The results indicate that dynamic plant characteristics do affect the characteristics of plant motion. However, the plant motion was relatively insensitive to the range of ζ and fn we observed because fn, was well above the frequencies of high wind energy.
Supplemental Calcium Application on Yield, Grade, and Seed Quality of Runner Peanut
Authors: Adams James F. , Hartzog Dallas L. , Nelson Donald B. 
Published: July 2010

AbstractThe need for supplemental Ca continues to be the most likely nutritional problem of peanut (Arachis hypogaea L.) production on acid, sandy, and low cation exchange capacity (CEC) soils. The need for supplemental Ca from gypsum for improved yield, quality, and seed germination of four runner‐type cultivars was evaluated on 14 sites with a range in available soil Ca of 48 to 242 mg kg−1 during 1987 to 1989. Yields of all four cultivars were increased by addition of gypsum at the five sites with the lowest Mehlich‐1 extractable Ca (< 158 mg kg−1), although the magnitude of response varied among cultivars. Increases in sound mature kernal occurred for GK 7 and Southern Runner at soil Ca levels higher than that required for maximum yield. Calcium composition of nuts also was affected more by supplemental gypsum than was either yield or SMK. Germination percentage and seedling survival were both highly correlated with seed‐Ca concentration. Minimum seed Ca needed for maximum germination ranged between 368 and 414 mg kg−1 for the four cultivars. Comparable Ca values for seedling survival ranged between 361 and 445 mg kg −1. The correlations between soil Ca and either germination or seedling vigor were less than those between seed Ca and germination or seedling vigor. All correlations involving Ca and germination suggest that soils used to produce seed, probably need a higher level of available Ca than those used for general production.
Plant Growth Regulator Effects on Growth and Forage Quality of Tall Fescue
Authors: Reynolds J. H. , Krueger W. A. , Walker C. L. , Waller J. C. 
Published: July 2010

AbstractForage quality of tall fescue (Festuca arundinacea Schreb.) is low in the spring after heading. Plant growth regulators (PGRs) have been shown to improve forage quality through inhibition of seedhead development. The objective of this study was to compare the effect of fall or spring application of six PGRs on heading, yield, and forage quality of tall fescue. The soil was an Etowah silt loam (fine‐loamy, siliceous, thermic Typic Paleudults). Precipitation was more favorable in the second year of the experiment than in the first. Sethoxydim (2‐[1‐(ethoxyimino)butyl]‐5‐[2‐(ethylthio)propyl]‐3‐hydroxy‐2‐cyclohexen‐1‐one) at 70 g ha−1, haloxyfop methyl (methyl 2‐[4‐[[3‐chloro‐5‐trifluoromethyl)‐2‐pyridinyl]oxy]phenoxy]propanoic acid) at 45 g ha−1, and mefluidide (N‐[2,4‐dimethyl‐5‐[[(trifluoromethyl)‐sulfonyl]amino]phenyl]acetamide) at 280 g ha−1 were the most consistent in reducing head density, forage yield, and neutral detergent fiber (NDF) and increasing crude protein (CP) of the May harvest. The PGRs were more effective in reducing yield, head density, and NDF and increasing CP of the May harvest when applied in April than when applied in December of the second year. Responses to the PGRs in the May harvest were fewer in the first year when precipitation was less favorable. Only one PGR increased in vitro dry matter digestibility (IVDMD) in the second year and none increased it in the first year. Four April‐applied PGRs decreased NDF in the first year's regrowth and April‐applied sethoxydim and December‐applied mefluidide increased CP in both years' regrowth. Forage quality was not consistently improved by the use of PGRs on tall fescue. An effective PGR may be more useful in turf areas than on forage because it reduces yield substantially.
Development of Double‐Crop Soybean under Different Soil Water Regimes
Authors: Pearce R. C. , Grabau L. J. , Grove J. H. , Lin H. 
Published: July 2010

AbstractDouble‐crop soybean [Glycine max (L.) Merr.] comprises nearly one‐third of the total soybean hectarage in the southeastern USA. This study was initiated to investigate the water relations of soybean following winter wheat [Triticum aestivum (L.) emend. Thell], with emphasis on the role of stored soil water. A treatment scheme was devised in which wheat was killed at heading, mid‐grain fill, and maturity, resulting in three different levels of stored soil water at soybean planting. In 1986, soil water levels at planting were 26.0, 23.1 and 21.4 cm of water in the 0.9‐m profile, respectively. A relatively dry early summer resulted in poor soybean stands and slow early growth; however, rainfall was well distributed during the latter half of the growing season. Soybean yields in 1986 were 2.76, 1.60, and 0.44 Mg ha−1, respectively. Initial soil water levels in 1987 were 31.1, 27.5, and 25.1 cm of water in the 0.9‐m profile. A wet early summer resulted in good stands and vigorous early growth, but a late summer drought caused severe stress during the reproductive growth period. Soybean yields recorded in 1987 were 0.97, 0.54, and 0.30 Mg ha−1, respectively. In 1989, soil water levels at planting were 33.1, 34.3, and 31.6 cm and associated yields were 1.51, 1.81, and 1.11 Mg ha−1. Rainfall was above average and well distributed during the 1989 season. Within each of the years there was a positive relationship between soil water level at planting and yield of double‐crop soybean; however, between years the amount and distribution of rainfall had a more dominant influence on yield than did soil water level at planting.
Application Placement and Timing of Nitrogen Solution for No‐Till Corn
Authors: Stecker J. A. , Buchholz D. D. , Hanson R. G. , Wollenhaupt N. C. , McVay K. A. 
Published: July 2010

AbstractFertilizing no‐till corn (Zea mays L.) with urea‐based N sources requires managing for N losses such as immobilization and NH3 volatilization. In this study the interactive effects of fertilizer N application time and placement method were evaluated by applying urea ammonium nitrate (UAN) solution to no‐till corn. Eight site‐years of data were collected from sites in central, northeast, and northwest Missouri on Ochraqualf, Albaqualf, and Udifluvent soils, respectively. Experimental design was a complete factorial of N application time (preplant and sidedress), placement method (knife, dribble and broadcast) and rate (67, 135, and 202 kg N ha−1). Knife injected N increased yields relative to broadcast and dribbled N in five of eight site‐years. Yields from knife injected N ranged from 4 to 20% more than dribble and 5 to 40% more than broadcast. Ear‐leaf N concentration and grain N uptake were increased from knife injected N in six of the eight site‐years. Dribbled and broadcast UAN performed similarly in most site‐years for grain yield, ear‐leaf N and grain N uptake. Except for two site‐years in which sidedress resulted in lower grain yields, application time had no effect on grain yield. No interaction of application time and placement method was apparent, as knife injection was superior to broadcast and dribble at both application times. This suggests that N losses associated with surface application of urea‐based N sources were similar for preplant and sidedress application times.
Nitrogen Nutrition of Rainfed Winter Wheat in Tilled and No‐Till Sorghum and Wheat Residues
Authors: Knowles T. C. , Hipp B. W. , Graff P. S. , Marshall D. S. 
Published: July 2010

AbstractDecomposition of sorghum [Sorghum bicolor (L.) Moench] and wheat (Triticum aestivum L.) plant residues can immobilize enough surface‐applied N to cause a deficiency in successive winter wheat crops. This experiment examined the effects of conventional and no‐till grain sorghum and wheat residues on N requirements of dryland winter wheat. Field experiments conducted from 1987–1991 on an Austin silty clay (fine‐silty, carbonatic, thermic Udorthentic Haplustoll) soil included sorghum and wheat residue treatments with conventional till (CT), no‐till (NT), and residue removal (RR). All residue plots received four preplant N rates (0, 45, 90, and 135 kg N ha−1), with subplots planted to three winter wheat cultivars in 1988 and 1989, and two cultivars in 1990 and 1991. Grain and stover yields were significantly lower when wheat followed sorghum than under continuous wheat. Wheat grain yields at N application rates < 90 kg ha−1 were 39% lower in NT plots vs. CT plots, 5% lower in CT plots compared with yields in RR plots, and 39% lower in sorghum‐wheat rotation compared with continuous wheat. Wheat N uptake at N application rates <90 kg ha−1 was 41% lower in NT plots vs. N uptake in CT plots, 10% lower in CT plots vs. N uptake in RR plots, and 36% lower in sorghum‐wheat rotation vs. continuous wheat. Grain yield and N uptake of wheat at the 135 kg N ha−1 rate were not significantly different in NT and CT plots. Preplant soil NO3‐N analysis indicated a need for the application of N fertilizer at planting in CT and NT sorghum residues, and basal stem NO3‐N analysis showed wheat growing in NT residues and sorghum‐wheat rotations; had higher N fertilizer requirements than continuous CT wheat. Microbial immobilization of surface‐applied N was responsible for N deficiencies observed in NT winter wheat, while a decrease in fallow time between sorghum harvest and wheat planting dates was the primary cause for reduced mineralization rates of residue‐derived and indigenous soil N in sorghum‐wheat rotations. A fallow period following grain sorghum and/or band application of fertilizer N could alleviate N deficiencies observed in this study.
Grain Protein Response of Spring Barley to High Rates and Post‐Anthesis Application of Fertilizer Nitrogen
Authors: Bulman Patrick , Smith Donald L. 
Published: July 2010

AbstractBarley (Hordeum vulgare L.) is an important feed crop in eastern Canada. Although the grain is used mainly as a source of energy for monogastric animals, high grain protein concentration (GPC) is desirable. Commencing in 1987, a 4‐yr field trial was conducted at the E.A. Lods Agronomy Research Centre of McGill University to evaluate the effects of N application on the GPC of spring barley. Cadette and Leger, which are adapted feed cultivars, and Argyle, an unadapted malting type, were grown with N rates of 0, 50, 100, 150, and 200 kg N ha−1 broadcast at seeding as NH4NO3. Two other treatments consisted of applying 100 kg N ha−1 at seeding and 50 kg N ha−1 as NH4NO3 (broadcast) or urea (foliar solution) 6 to 10 d after awn emergence. Increasingly higher rates of N applied at seeding increased the amount of protein per grain, thereby increasing GPC. The amount of nonprotein dry matter (DM) per grain was consistent among treatments within seasons. In only one instance did fertilizer N increase GPC by reducing nonprotein DM per grain. Split N treatments increased GPC significantly more than a single application of equivalent N at seeding in only two seasons. A foliar‐applied urea topdressing generally increased GPC more effectively than broadcast NH4NO3. With individual cultivars, the GPC response to N treatments could be explained in terms of protein per grain. Cultivar differences in GPC were not always related to protein per grain. Argyle had the highest GPC values (129.1–160.6 g kg−1), but only because of poor nonprotein DM accumulation per grain.
Oat Cultivar Response to Potassium Chloride on Soils Testing High in Potassium
Authors: Gaspar P. E. , Reeves D. L. , Schumacher T. E. , Fixen P. E. 
Published: July 2010

AbstractYield responses of wheat (Triticum aestivum L.) and barley (Hordeum vulgare L.) to additions of KCl fertilizer on high‐K soils have been documented. One of the principal effects of KCl on high‐K soils is a reduction in foliar disease. Little research has been conducted on the effects on oat (Avena sativa L.) production of KCl on high‐K soils. The objective of this study was to evaluate the effects of adding KCl to high‐K‐test soils on grain yield, quality, plant water relations, crown rust (Puccinia coronata Corda) incidence, and lodging of commonly grown oat cultivars. The experiments were conducted at four locations in eastern South Dakota. Fertilization with KCl increased oat grain yields by 4% at two locations. Although the increase in grain yield was significant, it was too small to be profitable under current economic conditions. A significant increase in 1000‐kernel weight (4–7% relative to the control) occurred at locations with a yield response. Additions of KCl did not affect crown rust infection, protein, or oil content, relative water content, or stomatal conductance; however, KCl addition decreased solute potential adjusted for full turgor during the boot stage at two locations by 0.07 MPa. The decrease in adjusted solute potential was not consistently associated with a grain yield response.
Yield Component Compensation in Uniculm Barley Lines
Authors: Dofing S. M. , Knight C. W. 
Published: July 2010

AbstractAsynchronous spike maturation in barley (Hordeum vulgare L.) grown at northern latitudes, caused by late‐developing tillers, frequently results in harvest delay, reduced grain quality, and increased drying costs. The uniculm trait has been suggested to promote uniform spike maturation and increased grain yield; however, the literature contains no information on the field performance of genetic uniculm lines. The purpose of this study was to assess the performance and yield component compensation of uniculm barley lines having the uc2 gene. Five spring barley lines were grown at seeding rates of 35, 90, 145, and 200 kg ha−1 at Palmer and Fairbanks, AK in both 1991 and 1992. Higher seeding rates resulted in shorter plants, earlier maturity, increased spikes per square meter, and reductions in kernels per spike and kernel weight. Results from path analysis demonstrated that spikes per square meter was the primary determinant of grain yield, followed by kernels per spike, with kernel weight of only minor importance. Increasing spikes per square meter caused relatively large reductions in kernels per spike and kernel weight, while increasing kernels per spike caused only minor reductions in kernel weight. Maximum grain yield was attained at the 200 kg ha−1 seeding rate in Fairbanks and at the 90 or 145 kg ha−1 seeding rate at Palmer. The relatively low grain yield of uniculm lines appears to be due to a low number of kernels per spike at higher spike densities.
Warm‐Season Grass Productivity and Growth Rate as Influenced by Canopy Management
Authors: Belesky David P. , Fedders James M. 
Published: July 2010

AbstractWarm‐season grasses adapted to cool‐temperate environments can improve the seasonal distribution and supplement the productivity of forage systems in the northeastern USA. Management practices concerning clipping regimes for warm‐season grasses grown in the region, are not well understood. A 2‐yr field study was conducted to determine productivity and growth rates of flaccidgrass (Pennisetum flaccidum Griseb.), switchgrass (Panicum virgatum L.), bermudagrass (Cynodon dactylon L.), and Caucasian bluestem [Bothriochloa bladhii (Retz.) S.T. Blake] clipped according to sward height criteria. Treatments were replicated three times and included; first clipped at full heading; or 50% removal of short canopy and 50% and 75% removal of tall canopies at vegetative stages. Cumulative yields of warm‐season grasses were influenced by a complex clipping treatment, species, and year interaction. When first cut was made at a mature stage, 1990 and 1991 yields were similar, but were greater in 1991 than 1990 when cut early. Cumulative herbage yield of bermudagrass and Caucasian bluestem exceeded that of switchgrass and flaccidgrass when clipping was begun early in the growing season (species ✕ treatment interaction; P ≤ 0.01). Mean growth rates were greatest when canopies were managed as hay or when 75% of a tall canopy was removed, and were greater in 1991 than in 1990. Instantaneous growth rates suggest that bermudagrass and Caucasian bluestem appear to be better adapted to repeated defoliation than the tall‐growing species. Switchgrass and flaccidgrass may be best used in limited‐defoliation or conserved forage situations.
Reducing the Cost of Estimating Root Turnover with Horizontally Installed Minirhizotrons
Authors: Dubach Markus , Russelle Michael P. 
Published: July 2010

AbstractGrowth and decay of individual roots (i.e., root turnover) is difficult to quantify because the processes occur simultaneously in a root system. Minirhizotrons are promising tools for assessing root turnover in natural and managed ecosystems. We investigated methodological problems and improvements in using minirhizotrons to estimate root turnover. Root images were collected in field plots of alfalfa (Medicago sativa L.) and birdsfoot trefoil (Lotus carniculatus L.) through minirhizotrons installed horizontally before planting at six depths, from 7 to 70 cm, parallel to and directly below the crop rows. Forty video images (13 by 17 mm) were recorded at weekly intervals at 90° from vertical along both sides of the tubes. Images were edited into time‐lapse sequences and cumulative numbers of roots that appeared and disappeared at each location were determined manually over an entire growing season. This required ≈ 29 h of labor for each replicate of each depth (a total of 80 images in one tube), with the biggest share spent on editing. Accuracy and precision of results were not decreased by using only every second image along both sides of the tube (40 images), but declined when either only one side of the tube or only 20 consecutive images on both sides were used. Reducing the recording frequency further reduced labor requirements: depending on date of root appearance and observation depth, recording intervals could be lengthened to 2 wk for the 12‐cm depth and longer for greater depths without losing either accuracy or precision. Analyzing every second image and increasing the time interval between recordings resulted in projected labor savings of ≥70%, while maintaining data integrity.
Rooting Characteristics and Associated Drought Resistance of Zoysiagrasses
Authors: Marcum Kenneth B. , Engelke M. C. , Morton Sharon J. , White Richard H. 
Published: July 2010

AbstractDeclining availability of water for landscape irrigation has increased the need for drought‐resistant turfgrasses. Though drought‐resistance mechanisms are known to include deep rooting in some plants, little is known concerning zoysiagrass rooting characteristics. This study was conducted to determine if differences in rooting parameters exist among zoysiagrasses, and if they are associated with drought resistance. Twentyfive zoysiagrasses cultivars and species [Zoysia japonica Steud., Z. matrella (L.) Merr., and Z. japonica Steud. ✕ Z. tenuifolia Willd. ex Trin.] were studied in polyethylene tubes in a glasshouse. Differences were observed for average maximum root depth (AMRD), total root weight, and root numbers and weights at increasing 100‐mm depth increments. Average maximum root depth was positively correlated with total root weight and root number and weight at increasing 100–ram depth increments. Grasses with superior AMRD, total root weight, and root numbers at deeper profile depths (300–500 mm) included QT2047, El Toro, DALZ8512, TC5018, Meyer, DALZ8514, and DALZ8516. In a previously reported field experiment, 11 of the 25 zoysiagrasses were rated for percent of plot area covered by green turfgrass (an indicator of drought resistance) under three levels of irrigation (0, 35, and 100% of turfgrass evapotranspiration [ET]). Average maximum root depth, total root weight, and root numbers at 200‐, 300‐, and 400‐mm depths in polyethylene root tubes were positively correlated with percent green plot cover in the field under deficit irrigation (0 and 35% ET), indicating that rooting depth, weight, and branching at lower depths are important droughtresistance mechanisms in zoysiagrasses.
Performance of Commercial Cotton Cultivars under Elevated Densities of Tobacco Budworm
Authors: McCarty Jack C. , Jenkins Johnie N. 
Published: July 2010

AbstractThe development of improved cultivars is essential for continued economic production of cotton, Gossypium hirsutum L. Information is limited on how different cotton cultivars compare under elevated densities of tobacco budworm, Heliothis virescens (F.), an economically important cotton pest. Seven field tests were conducted between 1988 and 1992 to evaluate cotton cultivars grown under elevated densities of tobacco budworm (TBW). Cultivars were grown under two regimes: (i) artificial elevated infestation, w/TBW, and (ii) elimination of tobacco budworm, w/o TBW. Elevated densities of TBW (w/TBW) significantly reduced yields compared with w/o TBW, but reduction varied among years and tests. The regression equation for lint yield w/TBW on lint yield w/o TBW was Y = −111.0 + 0.6X. Thus, for every 1.0 kg of lint yield increase per hectare due to cultivar improvement, the corresponding increase under artificial TBW infestation was only 0.6 kg. The regression coefficient for lint percentage on lint yield w/o TBW was Y = 30.85 + 0.006X. These data show that cotton breeders have developed high‐yielding cultivars, but that progress is still needed in the development of resistance to the tobacco budworm injury. They also show that, as cultivars with higher yield potential were developed, these cultivars were better able to tolerate damage by the tobacco budworm. The parity between yield increase per se and yield under elevated densities of tobacco budworm is not 1.0:1.0, but rather 1.0:0.6. This is a useful and practical level of parity.