bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Method for Infesting Small Field Plots with Soybean Cyst Nematode
Authors: Browde J. A. , Tylka G. L. , Pedigo L. P. , Owen M. D. K. 
Published: July 2010

AbstractField experimentation with soybean cyst nematode (Heterodera glycines Ichinohe) is difficult, because of problems in obtaining plots with desired population densities. Therefore, a technique was developed for infesting small field plots with soybean cyst nematode. In 1990 and 1991, cysts, eggs, and infective juveniles were mixed with soil and applied with a commercial fertilizer spreader. Infected soybean [Glycine max (L.) Merr.] root segments were distributed by hand. Infested soil and roots were incorporated with a tractor‐drawn herbicide incorporator, and plots were planted to susceptible soybean. At‐planting egg densities in 1990 and 1991 averaged 184 and 100 eggs 100 cm−3 soil, respectively, representing 78 and 90% of expected egg densities. Resultant low densities of encysted eggs, which are highly aggregated, probably prevented detection of eggs in some plots. No soybean cyst nematode was detected in uninfested plots at planting, although some contamination was noted at harvest. This method may be appropriate for establishing soybean cyst nematode population densities for some small‐plot research.
Residual Maize Fertilizer Nitrogen Availability to Wheat on the Southeastern Coastal Plain
Authors: Camberato J. J. , Frederick J. R. 
Published: July 2010

AbstractIn southeastern Coastal Plain soils, little emphasis is placed on adjusting N fertilization of a crop based on the residual N left from the preceding crop because of the perception of coarse‐textured surface soils, winter rainfall in excess of evapotranspiration, and shallow‐rooted crops. However, estimates of annual water surplus do not include a winter crop, which may reduce NO3‐N leaching, nor consider current tillage practices, which enable deep rooting, and assimilation of subsoil NO3‐N. This study was conducted to determine the contribution of N applied to a maize (Zea mays L.) crop to the N supply of a subsequent winter wheat (Triticum aestivum L.) crop. Wheat was grown following maize fertilized with various rates of N and poultry litter on a Rains/Lynchburg sandy loam soil complex (fine‐loamy, siliceous, thermic Typic/Aeric Paleaquult) in 1990 and on a Noboco loamy sand (fine‐loamy, siliceous, thermic Typic Kandiudult) in 1991. Maize fertilizer N increased soil NO3‐N at the time of wheat planting. Residual N increased wheat dry matter, N content, and grain yield. An increase in maize N rate of 134 kg N ha−1 increased N supply to the subsequent wheat crop by approximately 15 kg ha−1 and increased wheat grain yield by 0.8 Mg ha−1. Poultry litter did not differ from fertilizer N in providing residual N to the wheat. This research demonstrates that previous crop fertilization rate may impact N supply to the subsequent crop, even on coarse‐textured Coastal Plain soils.
Water‐Yield Relationships for Irrigated and Dryland Wheat in the U.S. Southern Plains
Authors: Musick Jack T. , Jones Ordie R. , Stewart Bobby A. , Dusek Donald A. 
Published: July 2010

AbstractA climate with high evaporative demand and limited precipitation restrict yields of winter wheat (Triticum aestivum L.) grown in the semiarid U.S. southern High Plains. Stress effects can be avoided or minimized by management practices that increase soil water storage at planting or by application of irrigation water. We analyzed a 178 crop‐year database of irrigated and dryland wheat data from Bushland, TX, to develop relationships that define the grain yield and water‐use efficiency (WUE) response to a wide range in seasonal evapotranspiration (ET) associated with water deficits and to evaluate yield response to stored soil water at planting. The ET‐grain yield relationship was determined as linear, with a regression slope of 1.22 kg grain per m3 ET above the ET threshold of 208 mm required to initiate grain yield. Maximum yields (>7.0 Mg ha−1) required 650 to 800 mm seasonal ET. Maximum yields observed in the combined database were 2.8 and 8.2 Mg ha−1 for dryland and irrigated wheat, respectively. The linear regression response of grain yield to soil water stored at planting, 1.57 kg m−3, was significantly higher than the yield response to seasonal ET. Largely similar WUE values occurred over a wide range of seasonal ET within irrigated and dryland data sets; however, WUE values for irrigated wheat averaged about double the values for dryland wheat. A curvilinear relationship determined between WUE and yield emphasizes the importance of obtaining high yields for efficient water use.
Sulfur Fertilization of Smooth Bromegrass in Kansas
Authors: Lamond Ray E. , Whitney David A. , Marsh Brian H. 
Published: July 2010

AbstractSulfur deficiencies have been identified throughout the central USA with increasing frequency in recent years, yet little work has been reported on S needs of perennial cool‐season forage grasses. Field studies were initiated on established smooth bromegrass (Bromus inermis Leyss.) at three sites in eastern Kansas to evaluate the effects of S fertilization on forage production and quality. Sulfur rates (0, 17, 34 kg ha−1) and sources (ammonium sulfate and ammonium thiosulfate) were evaluated with a uniform N application of 134 kg ha−1. Sulfur fertilization generally increased bromegrass forage production. Averaged across site‐years, forage yields were increased 700 kg ha‐1 annually by S application. The 17 kg S ha−1 rate was sufficient to achieve forage yield increases. Sulfur fertilization had little effect on bromegrass forage protein levels at normal harvest time, but did increase forage S concentrations. Forage protein levels of early‐season forage samples were increased by S application. When N /S ratios of the no‐S check treatments were 20:1 or greater, forage yields were increased with S application. Ammonium sulfate and ammonium thiosulfate performed equally well as S sources.
A Simple Conductimetric CO2 Analyzer with Automatic Recalibration: III. Dynamic Response
Authors: Wall Gerard W. , Acock Basil 
Published: July 2010

AbstractConductimetric CO2 analyzers provide an economical means of monitoring and controlling carbon dioxide concentration ([CO2]) in plant growth cabinets. When conductimetric CO2 analyzers are being used to measure canopy CO2 uptake over a period and compare that with light received, it is essential to know the time between an air sample leaving the canopy and its [CO2] being registered by the analyzer. A four‐way analysis of variance in three replicates of a split split‐plot design was used to examine the response time of the conductimetric CO2 analyzers to successive step changes in [CO2] (∆[CO2]) from 200 to 400, 600, 800, and 1000 μL L−1, at temperatures of 10, 20, 30, and 40°C, at air flows rates of 540, 1880, and 3700 mm3 s‐1, and at water flow rates of 1.0, 0.66, and 0.33 mL s−1. Response times ranged from 30 to 542 s across all treatments. Significant differences were observed between individual conductimetric CO2 analyzers, with response time means ranging from 99 to 145 s. Each analyzer, therefore, is unique and must be recalibrated following a change in any one component. A significant water flow rate ✕ temperature interaction was observed (response time means ranged from 86 to 177 s). Comparing these response time means to the 900‐s sampling period indicates that an individual conductimetric CO2 analyzer will adjust to the new steady state following a change in control within 9.5 to 20% of the sampling period. Only 1 data record out of 96 within a diurnal cycle is lost if an alteration in the CO2 control set point for the plant growth cabinet is made. This data loss is acceptable.
Potential for Discriminating Crop Residues from Soil by Reflectance and Fluorescence
Authors: Daughtry C. S. T. , McMurtrey J. E. , Chappelle E. W. , Dulaney W. P. , Irons J. R. , Satterwhite M. B. 
Published: July 2010

AbstractCrop residues left in the field after harvest can be important in controlling soil erosion. Current methods for quantifying percent crop residue cover are tedious and somewhat subjective. There is a need for new methods to quantify residue cover that are rapid, accurate, and objective. We evaluated reflectance and fluorescence techniques for discriminating crop residues from a wide range of soils. Reflectance and fluorescence spectra of 37 agricultural soils (wet and dry) and of recently harvested and weathered corn (Zea mays L.), soybean [Glycine max (L.) Merr.], sorghum [Sorghum bicolor (L.) Moench], and wheat (Triticum aestivutn L.) residues were measured in the lab. Reflectance factors in the visible or near‐infrared wavelengths did not uniquely distinguish all soils from all crop residues. Crop residues may be brighter or darker than a given soil, depending on soil moisture and residue age. When illuminated with ultraviolet radiation, however, the crop residues fluoresced more than most of the soils. Fluorescence of crop residues was a broad‐band phenomenon centered between 420 to 520 nm and induced by a relatively broad range of excitation wavelengths centered betweert 350 to 400 nm. More than 90% of the crop residues <2 yr old could be discriminated from 33 of 37 dry soils and 36 of 37 wet soils using fluorescence. The threshold for discrimination can be optimized for classification accuracy for each soil. Fluorescence techniques are less ambiguous than reflectance methods and are better suited for discriminating crop residues on soils. Furthermore, if properly implemented, fluorescence techniques can be used to quantify crop residue cover in the field.
Analysis of Deterministic Simulation Models Using Methods Applicable to Two‐Way Treatment Structures without Replication
Authors: Willers Jeffrey L. , Wagner Terrence L. , Sequeira Ronaldo A. , Theseira Gary W. , Boykin Deborah L. 
Published: July 2010

AbstractSeparate executions of deterministic simulation models are not independent replications in the strictest sense and, therefore, it is difficult to statistically analyze model output, since estimates of the error variance for the model are difficult to obtain. However, an analysis of simulation output is desirable. Presented here is a method that permits the statistical analysis of deterministic simulation output or its comparison to other output or experimental data. These analyses are possible when conditions imposed on the computer‐generated experiment conform to a two‐way treatment structure. The response data can be comprised of (i) model output, (ii) differences between experimental means and the model, or (iii) differences between individual output across treatment levels. The additive main effects and multiplicative interaction (AMMI) model for unreplicated data supplies several statistical tests. Foremost, the characteristic root test indicates if interaction exists between the two treatments. If interaction exists, the AMMI model can be used to determine which treatment combinations are involved. Once sources of interaction have been identified, it is then possible to obtain a good estimate of the error variance, even though these data are unreplicated. Using this estimate of the error variance, it is possible to test hypotheses of interest on model performance. An AMMI analysis comparing the output of a deterministic soil hydrology model to (replicated) experimental data is presented.
Yield and Yield Components of Spring‐Sown White Lupin in the Southeastern USA
Authors: Noffsinger Steven L. , van Santen Edzard 
Published: July 2010

AbstractManagement studies must be conducted to realize the full potential of white lupin (Lupinus albus L.) as a grain crop for the southeastern USA. This experiment examined planting date, row spacing, and seeding rate effects on grain and biomass yield of spring‐sown white lupin. In 1991 and 1992, field studies were conducted in northern Alabama on a Wynnville fine sandy loam (fine‐loamy, siliceous, thermic Glossic Fragiudult), in central Alabama on a Hiwassee sandy loam (clayey, kaolinitic, thermic Typic Kanhapludult), and in southern Alabama on a Lucedale fine sandy loam (fine‐loamy, siliceous, thermic Rhodic Paleudult). Treatments included three planting dates, three row spacings (17.5, 35, and 70 cm), three seeding rates (17.5, 35, and 52.5 seeds m−1), and two cultivars (Primorsky and Ultra). Prevailing weather allowed only one planting date in northern Alabama in 1991 and 1992. In the second year of the study, only one and two plantings were successful in central and southern Alabama, respectively. Grain yields averaged 551 kg ha−1 in 1991 and 604 kg ha−1 in 1992. Grain and biomass yield was always highest in northern Alabama. Planting date affected grain and biomass yield the most in central and southern Alabama in 1991. Decreased row spacing increased grain yields as much as 10 kg ha−1 per unit decrease in spacing. Grain yields increased as much as 19 kg ha−1 for every unit increase in seeding rate. Principal component analysis of yield components created factors branch, seed mass, and mainstem, which accounted for 57, 23, and 14% of the original variance, respectively. Factors branch and mainstem were highly correlated (r < 0.75) with grain and biomass yield. Seed mass and mainstem were highly correlated with harvest index (r < 0.65). For the southeastern USA, high yields in spring‐sown white lupin will require (i) early seeding, (ii) narrow row spacing, and (iii) high seeding rates.
Diagnosing Nutrient Deficiencies in Soybean, Using M‐DRIS and Critical Nutrient Level Procedures
Authors: Bell Paul F. , Hallmark William B. , Sabbe W. E. , Dombeck D. G. 
Published: July 2010

AbstractPlant nutrient deficiencies may be diagnosed with DRIS (diagnosis and recommendation integrated system) or critical nutrient level (CNL) procedures. While extensive efforts have been made to improve diagnoses by DRIS and M‐DRIS, little has been done to refine CNL diagnoses for soybean [Glycine max (L.) Merr.]. In this study, we compare diagnoses made by M‐DRIS with those from CNL and modify these procedures to improve their diagnostic accuracy. Two databases of R2 (full bloom) soybean leaf nutrient concentrations from 828 field observations of known K, Mn, Zn, or P deficiencies or sufficiencies were used for comparing the procedures. We optimized critical nutrient levels (modified CNL) using the same cases from a database that was used earlier to improveM‐DRIS. Using this optimization database, the M‐DRIS and modified‐CNL procedures had ≤ 13 misdiagnoses each of K nutrient status compared to 81 by unmodified CNL. M‐DRIS was more accurate than the two CNL procedures in diagnosing P deficiencies from cases in the optimized and independent data sets. Unmodified CNL produced 18 misdiagnoses for Zn status from cases in the independent data set, versus >27 for M‐DRIS or modified CNL. Generally, M‐DRIS was the same or more accurate than CNL methods in diagnosing nutrient status. We recommend CNL concentrations for R2 stage soybean of 3.1 g P kg−1, 15.1 g K kg−1, 17 mg Mn kg−1, and 21 mg Zn kg−1. For M‐DRIS, we recommend critical index values of zero for K and Mn, 18 for P, and −19 for Zn.
Establishment, Forage Production, and Nutritive Value of Leucaena in Central Florida
Authors: Austin M. T. , Williams M. J. , Hammond A. C. , Frank J. H. , Chambliss C. G. 
Published: July 2010

AbstractTree and shrub legumes are increasingly being recommended for forage use in the tropics and subtropics. A forage production trial to evaluate members of the genus Leucaena varying in their level of resistance to the leucaena psyllid, Heteropsylla cubana Crawford, was conducted for 3 yr at the USDA‐ARS Subtropical Agricultural Research Station in central Florida. A total of eight selections (one or more of L. leucocephala, L. pallida, or L. esculenta, and hybrids L. diversifolia ✕ L. pallida, L. pallida ✕ L. leucocephala, and L. diversifolia ✕ L. leucocephala) were evaluated for establishment, winter survival, total dry matter (DM), edible DM (stems < 6 mm diam. + leaves), percentage of edible DM, and N and in vitro organic matter digestibility (IVOMD) concentration of the edible DM. Seedlings were transplanted in a double hedgerow pattern (two rows 1 m apart, with 0.25 m within‐row spacing) in Blichton loamy fine sand (Arenic Plinthic Paleaquult) in June 1989. Winter survival of the selections ranged from 48 to 62% and did not differ among selections. The three L. leucocephala selections had the highest edible DM yields averaging 14 Mg ha−1 yr−1 DM in yr 2 and 3. Nitrogen concentration ranged from 31 to 49 g kg−1 and IVOMD concentration from 350 to 560 g kg−1, with the L. leucocephala selections exhibiting the highest IVOMD. Leucaena esculenta had lower levels of both N and IVOMD concentration, averaging 37 and 380 g kg−1, respectively. Based on yield and nutritive value, L. leucocephala selections K584 and K636, although having less psyllid resistance than the hybrids or other species, appear to be better suited for central Florida.
Traffic Pattern and Tillage System Effects on Corn Root and Shoot Growth
Authors: Kaspar Thomas C. , Logsdon Sally D. , Prieksat Mark A. 
Published: July 2010

AbstractControlled wheel traffic is one way to manage compaction in no‐till and ridge‐till systems. This study was conducted from 1990 to 1992 at Kanawha, IA, on a Webster silty clay loam (fine‐loamy, mixed, mesic Typic Haplaquoll) to examine the effect of a wheel traffic pattern on corn (Zea mays L.) root distribution, shoot growth, and yield in no‐till, ridge‐till, and chisel‐plow tillage systems. The wheel traffic pattern was configured so that some rows would have wheel tracks on both sides, on one side, or on neither side. Bulk density, hydraulic conductivity, root length density, shoot dry weight, and yield were measured at several positions across the traffic pattern. In general, the effect of tillage systems was not significant averaged across positions. Position relative to the traffic pattern had some effect, however, on all measured parameters. Bulk density was greatest in trafficked interrows (1.36 Mg m~3) and least in untrafficked interrows (1.09 Mg m−3). Hydraulic conductivity near saturation was less in trafficked (39.4 μm s−1) than in untrafficked (104.7 μm s−1) interrows. Root length density in trafficked interrows was on average one‐third of that in untrafficked interrows. Root length density in a particular interrow also was influenced by the traffic pattern in the adjacent interrows. In 2 of the 3 yr, yields of rows with a trafficked interrow on only one side were 7% less than those of rows without trafficked interrows on either side. The wheel traffic pattern, and not just the presence or absence of wheel traffic, affected corn root growth and yield.
Carrousel Sprayer: A Self‐Cleaning Plot Sprayer for Large‐Scale Field Trials
Authors: Loussaert Dale 
Published: July 2010

AbstractLarge‐scale chemical screening requires efficient, accurate means for treating a large number of small experimental units. A new, self‐cleaning chemical field sprayer design was developed to increase productivity, reduce costs, and improve precision. Sprayer units are arranged symmetrically on a carrousel‐like fixture, so the sprayer units can be rotated to various fixed stations around the carrousel. The different sprayer units are loaded, sprayed, and rinsed simultaneously at the different stations as the sprayer moves through a plot. The sprayer units are rotated to the next station between plots, to allow continuous loading, application, and cleaning of the sprayer units as treatments are applied. One‐meter test plots can be sprayed every 4 s with less than 0.2% contamination between samples. The sprayer provides the capability of treating 5000 to 6000 plots per day.
Seedling Vigor and Grain Yield of ‘Roblin’ Wheat Affected by Seed Size
Authors: Gan Yantai , Stobbe Elmer H. 
Published: July 2010

AbstractCommercial spring wheat (Triticum aestivum L.) seedlots contain a small proportion of small‐sized seeds. Wheat producers often remove small‐sized seeds, attempting to increase seedling vigor and grain yield. A 3‐yr study was conducted from 1989 to 1991 on a Neuhorst clay loam (Aquic Haploborolls) to determine the effect of seed size and proportion of small seeds in a seedlot on emergence, dry matter (DM) production, and grain yield of ‘Roblin’ wheat. A commercial seedlot containing seeds >2.2 but <3.2 mm in width was designated as the original seedlot and was divided into 11 sublots: five with uniform seed sizes (2.2‐2.4, 2.4‐2.6, 2.6‐2.8, 2.8‐3.0, and 3.0‐3.2 mm wide), three with variable seed sizes (2.4‐3.2, 2.6‐3.2, and 2.8‐3.2 mm wide), and three more sublots from which seeds <2.2, <2.4, and <2.6 mm wide were successively removed, with the remaining seeds planted at correspondingly reduced planting density. The use of uniform large seeds increased shoot DM in 1990 and 1991, but not in 1989. Grain yield was increased with uniform large seeds only for the early planting in 1990, where soil temperature was low. A small proportion of small seeds in a seedlot decreased shoot DM in two of six cases, but in no case decreased percent emergence or grain yield. When small seeds were removed, the remaining seeds, planted at 278 and 236 seeds m−2. had grain yields equivalent to that of the original seedlot planted at 300 seeds m−2. There is thus no need to remove small seeds from a seedlot that has been commercially cleaned, and, if uniform large seeds are available for planting, seeding rate can be reduced.
Grain Yield and Water Consumption of Ethephon‐Treated Corn under Different Irrigation Regimes
Authors: d'Andria Riccardo , Chiarandà Fabrizio Quaglietta , Lavini Antonella , Mori Mauro 
Published: July 2010

AbstractEthephon (2‐chloroethyl phosphonic acid) has been widely studied under field conditions as a growth regulator to enhance yield in corn (Zea mays L.) by controlling lodging. However, few studies have examined the interaction between ethephon and soil water availability on grain yield and growth patterns of corn. The objective of this research was to study the effects of ethephon rates and timing of applications in combination with different irrigation levels on water use, yield and its attributes, total dry matter accumulation, LAI, and plant height. The 2‐yr study (1993–1994) was carried out at the CNR Irrigation Institute experimental farm in southern Italy (14°50' E, 40°07' N; sandy‐clay soil) using corn (cv. Aida, FAO class 500). Treatments consisted of four irrigation regimes and four and six ethephon treatments for 1993 and 1994, respectively, in a randomized complete block design with three replicates. Irrigation regimes were a rainfed control (T0) and three treatments replenishing the soil water profile to field capacity to a depth of 0.7 m at different frequencies: Tw, weekly irrigation; T2, irrigation at two growth stages (VT and R1); and T4, irrigation at four stages (V7, VT, R1, and R4). Ethephon was applied both years at the V5 stage at rates of 280, 560, and 840 g a.i. ha−1. In 1994, two additional treatments were included by applying, at the V9 stage, an additional 280 g ha−1 of ethephon to treatments that had previously received 280 or 560 g a.i. ha−1. Increasing ethephon rates caused a significant reduction in LAI, plant height, and dry matter accumulation, resulting in a reduction in water consumption. In the rainfed control, increasing the ethephon rate resulted in a linear increase in yield, with maximum increase of about 200% (1.6 t ha−1) and 75% (1.7 t ha−1) in 1993 and 1994, respectively. By contrast, treatments irrigated four times showed a linear decrease of about 13% in both years. Ethephon treatment had no effect on grain yield in the Tw and T2 treatments. Kernel number was the yield component with the greatest influence on grain production. Our results suggest that ethephon may increase grain yield when natural or artificial water supply is a limiting factor.