bluuebunny/crossref_metadata_2025_split huggingface dataset:
Seedbed Tillage and Irrigation Effects on Yield of Mono‐ and Doublecrop Soybean and Wheat on a Silt Loam
Authors: Wesley R. A. , Heatherly L. G. , Pringle H. C. , Tupper G. R. 
Published: July 2010

AbstractDoublecropping soybean [Glycine max (L.) Merr.] and wheat (Triticum aestivum L.) is an accepted cropping system in the Midsouth. Soybean is either planted after wheat with subsoiling or disking and harrowing, or both, to prepare a seedbed, or is seeded directly into the wheat stubble. The objective of this study was to determine the yield response of ‘Forrest’ soybean (Maturity Group V) when planted in a conventional monocrop system and in conventional and no‐till doublecrop systems following wheat. The three cropping systems were evaluated in both an irrigated and nonirrigated environment on a Dundee silt loam (fine‐silty, mixed, thermic Aerie Ochraqualf), making a total of six treatments. The six treatments were arranged in a randomized complete‐block design with four replicates, and remained in the same location for the duration of the 3‐yr study. Soybean was planted at a rate of 44 kg ha−1 in rows 1 m apart, whereas wheat was drill‐seeded at a rate of 101 kg ha−1 in rows 0.18 m apart. Average wheat yields for the four doublecrop treatments were not significantly different within or across years. The 3‐yr average was 3475 kg ha−1. Irrigated monocrop soybean produced the highest average yield of 3165 kg ha−1, whereas nonirrigated monocrop soybean and the irrigated doublecrop soybean with either no seedbed tillage or conventional seedbed tillage averaged 2491,2596, and 2740 kg ha−1, respectively, and were statistically similar. Yields from the nonirrigated doublecrop soybean with no‐till and conventional seedbed tillage were the lowest and averaged 1940 and 1909 kg ha−1, respectively. Soybean yields from all treatments in both the irrigated and nonirrigated environments decreased in a nearly linear fashion from 1984 to 1986. This was largely due to a decline in the number of seed produced, and was apparently caused by higher maximumminimum temperatures during the R1 to R5 growth periods as the experiment progressed in time.
Statistical Analysis of a Yield Trial
Authors: Zobel Richard W. , Wright Madison J. , Gauch Hugh G. 
Published: July 2010

AbstractYield trials frequently have both significant main effects and a significant genotype X environment (GE) interaction. Traditional statistical analyses are not always effective with this data structure: the usual analysis of variance (ANOVA), having a merely additive model, identifies the GE interaction as a source but does not analyze it; principal components analysis (PCA), on the other hand is a multiplicative model and hence contains no sources for additive genotype or environment main effects; and linear regression (LR) analysis is able to effectively analyze interaction terms only where the pattern fits a specific regression model. The consequence of fitting inappropriate statistical models to yield trial data is that the interaction may be declared nonsignificant, although a more appropriate analysis would find agronomically important and statistically significant patterns in the interaction. Therefore, agronomists and plant breeders may fail to perceive important interaction effects. This paper compares the above three traditional models with the additive main effects and multiplicative interaction (AMMI) Model, in an analysis of a soybean [Glycine max (L.) Merr.] yield trial. ANOVA fails to detect a significant interaction component, PCA fails to identify and separate the significant genotype and environment main effects, and LR accounts for only a small portion of the interaction sum of squares. On the other hand, AMMI analysis reveals a highly significant interaction component that has clear agronomic meaning. Since ANOVA, PCA, and LR are sub‐cases of the more complete AMMI model, AMMI offers a more appropriate first statistical analysis of yield trials that may have a genotype X environment interaction. AMMI analysis can then be used to diagnose whether or not a specific sub‐case provides a more appropriate analysis. AMMI has no specific experimental design requirements, except for a two‐way data structure.
Ammonia Volatilization from Spring Wheat Plants
Authors: Parton W. J. , Morgan J. A. , Altenhofen J. M. , Harper L. A. 
Published: July 2010

AbstractPlant shoots may be a significant source of N loss in crops. Ammonia volatilization and CO2 exchange rates from ‘Olaf’ spring wheat (Triticum aestivum L.) plants exposed to low‐ and high‐N treatments were observed from heading through the hard kernel phenological stages. The plants were grown in growth chambers (Nunn clay loam soil [Aridic Argiustoll]) where whole‐plant gas‐exchange measurements were made using a plexiglass cuvette. Plants lost NH3 at fairly constant rates (60–120 ng NH3–N m−2 s−1) during the pre‐senescence time period (before milk ripe stage), but the loss rate increased to 200 to 300 ng NH3 m−2 s−1 during final plant senescence. A reverse pattern was observed in CO2 exchange rates. Rates of CO2 exchange ranged from 0.13 to 0.42 mg CO2 s−1 during heading, but dropped off (gradually in the high‐N treatment, abruptly in the low‐N treatment) as the plants began to senesce. The NH3 loss rates on a leaf‐area basis were similar for the low‐ and high‐N plants despite significantly higher N concentrations in high‐N plants. Twice the leaf area was attained by the high‐N plants, resulting in NH3 volatilization rates per plant roughly twice those observed in the low‐N plants. The results suggest that significant amounts of NH3 can be lost from wheat shoots.
Soybean Phosphorus and Potassium Deficiency Detection as Influenced by Plant Growth Stage
Authors: Hallmark W. B. , DeMooy C. J. , Mooris H. F. , Pesek John , Shao K. P. , Fontenot J. D. 
Published: July 2010

AbstractRecent data suggests that ignoring the effect of physiological age on nutrient status of soybean (Glycine max L.) can result in biased P, K, and Zn deficiency diagnoses by the diagnosis and recommendation integrated system (DRIS). To overcome this problem, the use of nutrient multiples in place of some nutrient ratios for calculating nutrient function values has been advocated. Also, accurate P, Mn, and Zn deficiency diagnoses have been made using a small R1 (initial‐bloom) DRIS data base. This study was conducted to determine: (i) if small R1 and R5 (initial pod‐fill) DRIS data bases can detect soybean P and K deficiencies from R2 (full‐bloom) plants, and (ii) if the use of nutrient multiples in the R5 data base improves P and K diagnoses. The R1 data base detected P and K deficiencies, but overemphasized P and underemphasized K diagnoses. The R5 data base overemphasized Ca and N and underemphasized P and K diagnoses. Differences in diagnoses were attributed to high ca (data base concentrations are expressed in lower‐case letters) and low p values in the R5 versus the R1 data base. To alleviate incorrect P diagnoses nutrient multiples involving ca were substituted for nutrient ratios of ca in the R5 data base. This improved (P<0.01) P diagnoses; however, diagnoses were not as accurate (P<0.l0) as P diagnoses by the Rl data base. These data indicate that the use of nutrient multiples in DRIS can improve nutrient diagnoses, but that more accurate predictions occur when plants are sampled at the same growth stage as the data base.
Supplemental Radiation Effects on Senescence, Plant Nutrients, and Yield of Field‐Grown Corn
Authors: Ottman M.J. , Welch L. F. 
Published: July 2010

AbstractThe lower leaves in a fully developed corn (Zea mays L.) canopy are heavily shaded at normal stand densities. The low photosynthetic photon flux density (PPFD) received by such leaves may initiate senescence, hinder nutrient uptake by roots, and limit crop productivity. Objectives of this study were to determine the influence of supplemental radiation within the canopy on leaf senescence, plant nutrient accumulation, and yield of corn in a high‐yielding environment. Fluorescent lamps were placed in the lower two‐thirds of a corn canopy in an irrigated field study conducted near Urbana, IL, on a Drummer silty clay loam (fine‐silty, mixed, mesic Typic Haplaquoll). Supplemental PPFD provided by the lamp banks varied from 0 to 42 and 0 to 121 μmol m−2 s−1 on a leaf surface basis in 1982 and 1983, respectively. Supplemental PPFD delayed leaf senescence, increased the carbohydrate status of the plant, and increased aerial N, P, and K accumulation by 90, 90, and 30%, respectively. A 54% increase in dry matter and a 36% increase in N and P concentration accounted for increased N and P accumulation, while increased K was accounted for by a 54% increase in dry matter and a 24% decrease in K concentration. Grain yield increased proportionally to supplemental PPFD, from approximately 10.6 to 16.3 Mg ha−1, while harvest index decreased slightly. Yield was associated with increases in weight per kernel, kernels per ear, and ears per plant of 11,14, and 25%, respectively. Knowledge and enhancement of factors controlling corn yield may lead to future reductions in the unit cost of corn production.
Sources and Timing of Spring Topdress Nitrogen on Winter Wheal in Idaho
Authors: Lutcher L. K. , Mahler R. L. 
Published: July 2010

AbstractFall‐applied N is poorly utilized by winter wheat (Triticum aestivum L.) in northern Idaho, because heavy winter precipitation leaches much of the N from the root zone. Nitrogen‐use efficiency can be improved by spring application. This study evaluates two N fertilizer sources, urea‐ammonium nitrate solution (UAN; 32% N) and prilled ammonium nitrate (AN; 34% N), as spring topdress materials and determines the growth stage at which N application would produce maximum yield. Four field studies were established on cropland initially containing less than 50 kg NO3−N ha−1. Winter wheat was seeded at 90 kg ha−1 at each site. Nitrogen was topdressed at 100 kg ha−1 in the spring as either UAN, AN, or a UAN‐bromoxynil/MCPA [3,5‐dibromo‐4‐hydroxybenzonitrile/(4‐chloro‐2‐methylphenoxy) acetic acid] tank mix at eight different growth stages. Parameters evaluated included: (i) leaf burn, (ii) stand vigor, (iii) tillering, (iv) weed control, and (v) yield. Temporary yellowing of plant leaves was noted following UAN applications at air temperatures > 14°C. The degree of yellowing or leaf burn exhibited a significant curvilinear correlation with air temperature (R2=0.89). Nitrogen application date affected stand vigor, tillering, weed control, and yield, with the best ratings occurring with N applications before Zadoks' growth stage 31. When study sites and N sources were pooled, yields were 5.4,4.9, 4.8, 4.6, 4.3, 4.1, 3.6, and 3.1 Mg ha−1 for wheat fertilized at growth stages 22,24,26,28,31,32,37, and 43, respectively. Significant N source X time of application interactions for winter wheat yield were observed at three study sites. At early N application dates (growth stages) yield differences attributable to AN or UAN were not observed; however, when N was applied after growth stage 31, UAN plots produced yields between 1 and 24% (average 6%) greater than AN‐fertilized plots. This was attributable to dry soil conditions that reduced AN movement into the soil plant‐root zone, coupled with foliar absorbtion of UAN by wheat plants.
Estimation of Acremonium Coenophialum Mycelium in Infected Tall Fescue
Authors: Roberts C. A. , Barton F. E. , Moore K. J. 
Published: July 2010

AbstractCurrent methods for assessing the infection level in tall fescue (Festuca arundinacea Schreb.) infected with the fungal endophyte, Acremonium coenophialum Morgan‐Jones & Gams, do not quantify mycelial dry matter. The objective of this study was the estimation of mycelium by chemical and spectral determination of chitin, a fungal cell wall polymer. Tall fescue samples with various proportions of infected plants were collected from paddocks established on a Cecil sandy loam (clayey, kaolinitic, thermic Typic Hapludult) soil. Samples were analyzed for chitin, and the chemical data were used to develop a spectral prediction equation using near infrared spectroscopy (NIRS). The calibration and validation coefficients of determination were 0.86 and 0.84, respectively. The validated equation was used in the prediction of chitin in 95 other samples collected from paddocks microscopically evaluated for percent infected plants, and microscopic data were regressed against predicted chitin. Percent infection, as predicted by the microscopic procedure, and chitin concentration were not correlated (P > 0.05). The NIRS calibration set was expanded to include samples collected in Illinois. The improved equation accounted for 91 and 89% of the variability in calibration and validation, respectively. The mean and standard error of calibration were 328 and 50 mg kg−1 dry matter (DM), respectively. The expanded equation was used to quantify chitin from spring and fall pastures in Illinois that contained 100% infected plants. Chitin in spring pastures ranged from 118 to 961 mg kg−1 DM and varied greatly. Fall chitin varied little and the maximum concentration was 596 mg kg−1 DM. We concluded that endophytic chitin in tall fescue could be quantified chemically and spectrally. If potential sources of error are accounted for, these procedures can be used to estimate relative A. coenophialum mycelium.
Compatibility of Five White Clover and Five Tall Fescue Cultivars Grown in Association
Authors: Pederson G. A. , Brink G. E. 
Published: July 2010

AbstractThe need for tall fescue (Festuca arundinacea Schreb.) pasture renovation due to a fungal endophyte (Acremonium coenophialum Morgan‐Jones and Gams) that causes fescue toxicosis in grazing cattle (Bos taurus L.) has given farmers the opportunity to add white clover (Trifolium repens L.) to their improved pastures. This study was conducted to determine the compatibility of five white clover and five tall fescue cultivars grown in association during two seeding years and to determine any interactions between cultivars. ‘Regal’, ‘Tillman’, ‘Louisiana S‐1’, ‘Osceola’, and MS Brown Loam Syn. #6 white clover were grown in all combinations with ‘Kentucky 31’, ‘Kenhy’, ‘Johnstone’, ‘Triumph’, and ‘Missouri 96’ tall fescue in two separate seeding year studies. The studies were grown on a Catalpa silty clay (fine, montmorillonitic, thermic Fluvaquentic Hapludoll) at Mississippi State, MS. Louisiana S‐1 associations produced significantly less total dry matter (DM) and white clover (WC) yield and more tall fescue (TF) yield than those of the other white clover cultivars across tall fescue cultivars. Triumph associations produced significantly less WC yield and more TF yield than those of the other tall fescue cultivars across white clover cultivars. No differences in total DM yield were observed for the tall fescue cultivars. No interactions between tall fescue and white clover cultivars were found in either seeding year. The cultivar relationships were constant over years an over harvests within years, though the botanical composition of the plots varied between harvests and years. Triumph was more competitive with white clover than the other tall fescue cultivars, and Louisiana S‐1 was less competitive with tall fescue than the other white clover cultivars during the seeding year. No advantage was found for any specific combination of white clover and tall fescue cultivars during the seeding year.
Corn Root Growth and Nitrogen Uptake as Affected by Ammonium Placement
Authors: Anghinoni I. , Barber S. A. 
Published: July 2010

AbstractStimulation of root growth in the N‐fertilized soil volume of placed N fertilizer has been observed, but no quantitative data are available. The objective of this research was to obtain quantitative data on the influence of the fractional soil volume fertilized with NH+4 on corn (Zea mays L.) root distribution between NH+4‐fertilized and unfertilized soil, and to determine the effect of N placement on N uptake and plant growth. A pot experiment with seven treatments and three replicates was conducted using Raub silt loam (fine silty, mixed, mesic Aquic Argiudolls). The treatments were six volume fractions of 1.00, 0.50, 0.20, 0.10, 0.05, and 0.02 of soil fertilized with NH+4 plus a no‐N treatment. Before use, the soil was leached to remove NO−3 and a nitrification inhibitor was added. The NH+4 rate was 90 mg N kg−1 of soil in the pot. Six‐day‐old corn plants were transplanted into pots with 3 kg of soil and grown for 14 d, and into pots with 15 kg of soil and grown for 40 d. Corn was grown for 14 d with all treatments and for 40 d with the 0.2 placement. Root length density (km m −3) was greater in the NH+4‐fertilized soil. Root distribution between the NH+4‐fertilized and unfertilized soil volumes, the same at 14 d and 40 d, can be described by the equation y = x0.70 (r2=0.99), where y is the fraction of total root length in the NH+4 ‐fertilized soil when NH+4 is mixed with x fraction of the soil. The effect of NH+4 on root distribution was similar to that observed in earlier studies with P. Shoot N concentration was not affected by NH+4 placement; however, plant weight and N uptake were less with the 0.5 and 0.2 placement treatments.
Ryegrass Cultivars and Endophyte in Tall Fescue Affect Nematodes in Grass and Succeeding Soybean
Authors: Pedersen J. F. , Rodriguez‐Kabana R. , Shelby R. A. 
Published: July 2010

AbstractAnnual ryegrass (Lolium multiflorum Lam.) is often double cropped with soybean [Glycine max (L.) Merr.] in much of the southeastern United States to provide winter grazing and ground cover. Little is known about the effect of annual ryegrass cultivars on nematodes associated with the grass, and with subsequent soybean crops. In several other taxonomically similar grasses, including tall fescue (Festuca arundinacea Schreb.) and perennial ryegrass (Lolium perenne L.), the presence of endophytic fungi imparts pest resistance to the grass. No information is available on the effect of these endophytic fungi on nematodes associated with the grass. Therefore, the objectives of this study were to determine: (i) the effect of annual ryegrass cultivars on nematodes in the grass and in succeeding soybean, and (ii) the effect of Acremonium coenophialum Morgan‐Jones and Gams in tall fescue on nematodes. Thirteen annual ryegrass cultivars, ‘Kentucky 31” tall fescue with and without A. coenophialum infection, and a nematode‐susceptible soybean check were grown for 7 wk in pots in the greenhouse in a Malibis sandy loam (fine‐loamy, siliceous, thermic Plinthic Palendults) soil known to be infested with high numbers of phytonematodes. Plants were then removed from the soil, and the soybean was seeded into the pots and grown for 7 wk. Significant differences among nematode populations in the annual ryegrass cultivars occurred, and the nematode numbers were generally higher in the soybean that followed. However, these increased numbers did not affect soybean performance. Therefore, it does not appear that the use of annual ryegrass‐soybean doublecropping systems will be effective in controlling most nematodes when using nematode‐susceptible soybean cultivars. In tall fescue, lower spiral [Helicotylenchus dihystera (cobb) Sher.] and stubby root [Paratrichodorus minor (culbran) Siddiqi) nematode numbers were associated with A. coenophialum in the grass. Since nematode damage has previously been associated with stand decline in tall fescue, breeders working in nematode‐infested areas should be aware that decreased pest resistance may be associated with the removal of A. coenophialum from tall fescue.
Use of Growing Degree Days to Project Sample Dates for Cereal Crops
Authors: Klepper Betty , Rickman R. W. , Zuzel J. F. , Waldman S. E. 
Published: July 2010

AbstractTimely field sampling of a developing crop requires careful organization of laboratory space, equipment, and personnel to maximize efficiency. This paper demonstrates how historical temperature data sets, planting dates, and plot site elevation and location can be used to project expected developmental stage for winter wheat (Triticum aestivum L.) plants at any site in the Pacific Northwest dryland wheat‐growing areas. Historical average temperature data from long‐term weather station records for over 50 sites in the Oregon‐Washington‐Idaho dryland cereal production areas are stored on a computer. A program selects the weather station site nearest to the plot site on the basis of latitude, longitude, and altitude. Average daily maximum and minimum temperatures from the weather station are used to generate daily growing degree days for the plot site. Growing degree days are used to predict crop development. Projections can be made of either the expected date for a particular developmental stage or the expected degree days for any given date. Projections are used to schedule sample dates.
Breakage Susceptibility of Corn Kernels in Relation to Crop Management under Long Growing Season Conditions
Authors: Vyn T. J. , Moes J. 
Published: July 2010

AbstractCorn (Zea mays L.) kernels are subject to breakage during postharvest handling. Manipulation of crop management factors has influenced kernel breakage susceptibility, but the effects of hybrid, plant density, harvest moisture content, and drying temperature on breakage susceptibility have not been studied under long growing season conditions. Field experiments were conducted in 1985 and 1986 at Ridgetown, Ontario. Five commercial hybrids were grown at different plant densities (5.5 and 7.0 plants m−2 in both years, and 6.3 plants m−2 in 1985), harvested at 300 and 240 g kg−1 moisture content (wet basis), and dried at different air temperatures (20, 40, and 80°C in 1985; 20 and 100°C in 1986) to approximately 150 g kg−1 moisture content. A Wisconsin breakage tester was used to measure breakage susceptibility. Small increases in breakage were consistently associated with increased plant densities. Reductions in breakage were sometimes associated with lower grain moisture content at harvest. The largest and most consistent changes in breakage susceptibility were due to changes in drying temperatures. Increased drying temperatures resulted in increased breakage, but there was variation among the hybrids in the size of the response. The results indicate that breakage susceptibility is an inherited trait that is also influenced by crop management. Kernel breakage can be reduced by proper choice of hybrids, drying at low air temperature, and harvesting at low grain moisture content. In both years, increased breakage susceptibility was related to higher levels of endosperm stress cracks, tendency towards roundness in shape, and increased levels of harvest damage in the form of visible chips or cracks.