bluuebunny/crossref_metadata_2025_split huggingface dataset:
Soil Type and Moisture Regime Effects on Fertilizer Efficiency Calculation Methods in a Nitrogen‐15 Tracer Study
Authors: Torbert H.A. , Mulvaney R.L. , Vanden Huevel R.M. , Hoeft R.G. 
Published: July 2010

AbstractResearch was conducted to determine the extent to which the method of calculation affects estimates of fertilizer N efficiency using 15N as a tracer. Corn (Zea mays L.) was grown at three locations in Illinois that varied widely in soil type. Three early‐season moisture regimes (ambient, ambient + 100 mm of excess water, and ambient + 150 mm of excess water) were established to obtain different fertilizer N efficiencies on each soil. Application of 15N‐enriched KNO3 (168 kg N ha−1) was made to a Drummer silty clay loam (fine‐silty, mixed, mesic Typic Haplaquoll) at DeKalb, a Cisne silt loam (fine, montmorillonitic, mesic Mollic Albaqualf) at Brownstown, and a Plainfield sand (mixed, mesic Typic Udipsamment) at Havana, IL. Fertilizer N efficiency was calculated from the difference between N uptake by fertilized versus unfertilized plants, from the amount of 15N recovered in the plant, and from the recovery of 15N in both the plant and soil. For the Drummer and Cisne soils, the three calculation procedures gave different percent fertilizer N efficiencies when averaged across moisture treatments, and different trends among moisture treatments. For the Plainfield soil, percent fertilizer N efficiency values were lower than those obtained for the Drummer or Cisne soil, and the method of calculation had very little effect. The results indicate that, for most soils, N fertilizer efficiency ratings vary with the method by which they are calculated. The present study demonstrates a need for standard terminology to help identify parameters used to define fertilizer efficiency.
Post‐Anthesis Ethephon Effects on Yield of Spring Barley
Authors: Ma B. L. , Smith Donald L. 
Published: July 2010

AbstractEthephon (2‐chloroethyl phosphonic acid) application after heading may enhance the grain yield of cereal crops such as barley (Hordeum vulgare L.) and wheat (Triticum aestivum L.) by altering grain‐filling processes. The objective of this study was to evaluate the effects of post‐anthesis (1 wk after heading) ethephon application on variables contributing to the grain yield of spring barley cultivars. A field experiment, with application of ethephon at three rates (0, 240, and 480 g a.i. ha−1) to two barley cultivars, Cadette and Leger, was conducted on Bearbrook clay soil (fine, mixed nonacid, mesic Humaquept) in Quebec, Canada in 1988, 1989, 1990. A post‐anthesis application of ethephon extended the grain‐filling period by 1 to 3 d with variation among both cultivars and years. The 1000‐grain weight of both cultivars significantly increased in all 3 years while no changes were found in the other yield components (spikes per square meter and grains per spike). Grain yield of Leger (conventional stature) was increased 5 to 12% more than unsprayed controls while Cadette (semidwarf) grain yield was either not altered or significantly reduced. These results indicate that under climatic conditions such as those prevalent in northeastern North America post‐anthesis application of ethephon can potentially enhance grain fill and yield of spring barley.
Evaluating Internal Zinc Requirements of Grain Crops by Seed Analysis
Authors: Rashid A. , Fox R. L. 
Published: July 2010

AbstractOur study tested the general opinion that foliar tissues are superior to seeds for determining the nutrient status of crops. Zinc requirements of leaves and seeds were estimated from yield response curves based on greenhouse pot culture experiments using two Zn‐deficient subsoils (Paaloa silty clay; clayey, oxidic, isothermic Humoxic Tropohumult; and Keahua silty clay loam; fine, kaolinitic, isohyperthermic Torroxic Hapulstoll) of Hawaii. These were fertilized with 0, 1, 3, 9, or 27 mg Zn kg−1 of soil. The order of grain yield response to Zn fertilization was: wheat (Triticum aestivum L.) < sorghum [Sorghum bicolor (L.) Moench] < rice (Oryza sativa L.) < millet [Pennisetum americanum (L.) Schumann] < soybean [Glycine max. (L.) Merr.] < cowpea [Vigna unguiculata (L.) Walp.] < corn (Zea mays L.). Fertilizer Zn requirements for near‐maximum grain yield was highest for cowpea (7.5 mg kg−1 soil) and lowest for wheat (0.5 mg kg−1 soil). Zinc concentrations (mg kg−1) in recently matured leaves associated with 95% maximum yields were similar for seven species: corn and millet, 24; soybean, 22; cowpea, 21; sorghum, 20; rice, 19; and wheat, 17. Equivalent concentrations for seeds were soybean, 43; cowpea, 26; corn, 18; millet, rice and wheat, 15; and sorghum, 10. Across all species, fertilizer levels and soils, the range of Zn concentration in leaves was 5 to 115 mg kg−1 (both values for corn); and in grains 6 (sorghum) to 59 mg kg−1 (wheat). Our results indicate that there was little reason to prefer leaves over grain as a diagnostic tissue for Zn; therefore, Zn should be added to the list of elements for which seed analysis may be advantageous.
Yield, Vegetative Growth, and Fiber Length of Kenaf Grown on Saline Soil
Authors: Francois L. E. , Donovan T. J. , Maas E. V. 
Published: July 2010

AbstractKenaf (Hibiscus cannabinus L.) is an excellent supplement to wood as a source of fiber for paper pulp. With the introduction of kenaf into the western USA, plantings may be on soils where salinity problems already exist or may develop from the use of saline irrigation water. Because of the lack of salt‐tolerance information on mature vegetative growth and yield, a 2‐yr field‐plot study was conducted at Brawley, CA. Two cultivars (Everglades‐41 and 7818‐RS‐10) were grown with six salinity treatments imposed on a Holtville silty clay [clayey over loamy, montmorillonitic (calcareous), hyperthermic Typic Torrifluvent]. Electrical conductivities of the irrigation waters, containing NaCl and CaCl2 (1:1 by weight), were 1.1, 2.0, 3.0, 4.0, 5.0, and 6.0 dS m−1. Soil salinity (electrical conductivity of the saturated‐soil extract, Kc) ranged from 5.4 to 12.6 dS m−1 the first year, and from 6.0 to 14.9 dS m−1 the second year. Vegetative growth, stem yield, and fiber length were measured. The mean dry weight yields of the stems during the 2‐yr experiment were reduced 11.6% for each unit increase in soil salinity above 8.1 dS m−1. These results place kenaf in the salt tolerant category. Yield reduction resulted from both a reduction in plant height and stem diameter. Increased salinity did not significantly affect fiber length. Excessive Cl accumulation occurred in the leaf tissues at high soil salinity levels.
Observer Variability for Disk Meter Measurements of Forage Mass
Authors: Aiken G.E. , Bransby D.I. 
Published: July 2010

AbstractInconsistency among research workers in estimating forage mass in grazing experiments would limit the value of forage mass estimates, but this problem has not been thoroughly examined. A study was conducted to determine variation among observers in using the disk meter to measure forage mass on tall fescue [Festuca arundinacea (L.) Schreb.] pastures which were grazed by steers (Bos taurus L.) at stocking rates of 2.0, 4.5, and 6.0 animals ha−1. Four observers, with varying degrees of training and experience, were used to visually identify sites which represented mean disk meter height (DMH), determine DMH from random location of DMH measurements, and calibrate the disk meter for estimating forage mass. There was an observer‐by‐stocking‐rate interaction for visual locations of sites considered to represent mean DMH. Slopes differed among observers for the regression of pasture DMH (estimated from randomly located sites) on stocking rate. Slopes for calibration equations also differed among observers. Results of this study indicate inconsistency among observers in using the disk meter to estimate forage mass, suggesting that caution should be taken when extrapolating forage masses from grazing experiments.
Modification of Infiltration Rates in an Organic‐Amended Irrigated
Authors: Martens D. A. , Frankenberger W. T. 
Published: July 2010

AbstractSlow water infiltration in some California soils results in considerable irrigation water loss through increased runoff and evaporation. This 25‐mo study was conducted to evaluate the effects of different organic amendments on soil physical parameters and water infiltration rates on an irrigated soil. Incorporation of three loadings (25 Mg ha−1 each) of poultry manure, sewage sludge, barley straw (Hordeum vulgare L.), and alfalfa (Medicago sativa L.) to an Arlington soil (coarseloamy, mixed, thermic Haplic Durixeralf) for 2 yr increased soil respiration rates (139‐290%), soil aggregate stability (22‐59%), organic C content (13‐84%), soil saccharide content (25‐41%), soil moisture content (3‐25%), and decreased soil bulk density (7‐11%). The change in soil physical properties resulted in significantly increased cumulative water infiltration rates (18‐25%) in the organic‐amended plots as compared with the unamended plots. Although additions of poultry manure and sewage sludge contributed to higher soil organic matter compared with straw and alfalfa, the straw amendment was statistically more effective in increasing soil aggregate stability, total saccharide content, infiltration rates, and soil respiration rates and in decreasing bulk density in the tillage zone. The increase in cumulative infiltration rates measured with the first organic addition (April 1987–January 1988) were significantly correlated with increased soil aggregation (P ≤ 0.01). Cumulative infiltration rates during the second (February 1988–September 1988) and third (October 1988–May 1989) organic incorporation were significantly correlated with decreased bulk density (P ≤ 0.01), but not with aggregate stability. Multiple linear regression analyses indicated that water infiltration rates in the organic‐amended soils were initially increased by stimulation of microbial activity, which increased the stability of soil aggregates. Cumulative infiltration rates were further increased by a decrease in soil bulk density with additional organic treatments to the tillage zone.
Drought Effects on Perennial Forage Legume Yield and Quality
Authors: Peterson P.R. , Sheaffer C.C. , Hall M.H. 
Published: July 2010

AbstractDrought frequently limits alfalfa (Medicago sativa L.) herbage productivity during mid‐summer in the North Central USA, but the productivity of other legumes during drought is unknown. We determined the effect of drought on the herbage yield and quality and stand persistence of birdsfoot trefoil (Lotus corniculatus L.), cicer milkvetch (Astragalus cicer L.), red clover (Trifolium pratense L.) and alfalfa. Legumes were established on a sandy, mixed, Udorthentic Haploborolls and subjected to two soil water regimes promoting ‘droughted’ and ‘well‐watered’ (control) plant growth. Mid‐day stem pressure potentials for droughted and control plants ranged from −1.3 to −3.8 MPa and −0.1 to −1.4 MPa, respectively. When drought occurred throughout growth, legume herbage yields of droughted alfalfa, birdsfoot trefoil, cicer milkvetch, and red clover averaged 33, 21, 19, and 13% of their respective controls. Average herbage yield of droughted alfalfa was 120% greater than yields of birdsfoot trefoil and cicer milkvetch, and 165% greater than red clover yield. Averaged for all harvests and species, whole herbage acid detergent fiber (ADF), neutral detergent fiber (NDF), and acid detergent lignin (ADL) concentrations were reduced by 30 to 4870, 26 to 46%, and 0 to 49%, respectively, when drought occurred throughout growth. Effects of drought on lignin in NDF and crude protein concentration were not consistent. Droughted alternative legumes produced herbage with lower ADF, NDF, and ADL concentrations than alfalfa. Improved quality in droughted legumes was related to greater leaf:stem weight ratio, delayed maturity, and often higher quality in both the leaf and stem fractions compared to the control treatment. Although drought reduced the herbage yield of all legumes, alfalfa has the greatest yield potential in drought.
Mepiquat Chloride and Irrigation versus Cotton Growth and Development
Authors: Reddy V. R. , Trent A. , Acock B. 
Published: July 2010

AbstractCotton (Gossypium hirsutum L.) produces excessive vegetative growth when grown under optimum water and nutrient conditions. The plant growth regulator Mepiquat Chloride (MC); 1,l‐dimethyl piperidinium chloride reduces vegetative growth and can promote early maturity. Its effect on yield has been inconsistent, with some researchers showing an increase while others have indicated a decrease. This variation in yield has often been attributed to environmental factors and variations in water and fertilizer inputs. This study examined the effect of MC on cotton growth, under varying irrigation treatments, to determine if soil moisture interacts with MC. The experiment was conducted in 1987 with two cotton cultivars, Stoneville 825 (‘ST825’) and Deltapine 20 (‘DP20’), grown in pots, with five irrigation treatments [1.2,1.0,0.8,0.6, and 0.4 times previous day's pan evaporation (PE)] each with and without MC applied. Mepiquat Chloride reduced plant height, number of main stem nodes, and internodal length. The effect on boll numbers was mixed between cultivars. In some instances under the same irrigation treatment (1.2 PE), the number of bolls was higher in ST825 with MC applied than with control while in DP20 the control treatment had the higher number of bolls. Mepiquat chloride's effectiveness on vegetative growth tended to decrease as the number of days after application increased. Differences in response within irrigation treatments was attributable to MC. Differences in response between irrigation treatments with MC applied was attributable to irrigation and cultivar differences and not to interaction between soil moisture and MC.
Chlormequat and Ethephon Timing and Grain Production of Spring Barley
Authors: Ma B. L. , Smith Donald L. 
Published: July 2010

AbstractSeveral plant growth regulators increase the number of spike‐bearing tillers and have potential as lodging control agents for spring barley (Hordeum vulgare L.). The objective of this study was to evaluate the effects of chlormequat (2‐chloroethyl trimethylammonium chloride, CCC) and ethephon (2‐chloroethyl phosphonic acid) timing on yield components, grain yield, and agronomic traits. A 4‐yr field study using the cultivars, ‘Leger’ and ‘Cadette’, was conducted on Bearbrook clay soil (fine, mixed nonacid, mesic Humaquept) at McGill University, in Quebec, Canada, from 1987 to 1990. Treatments consisted of application of CCC (1.2 kg ai. ha−1) and ethephon (0.48 kg ai. ha−1) at Zadoks growth stages (ZGS) 13, 30, and 39. Yield components were measured on a plot and a spike basis with separation of spikes into main culms and tiller culms. Early application of CCC at ZGS 13 enhanced grain number per spike, hut not grain yield due to compensations among yield components. At ZGS 30, ethephon application increased tiller‐derived spikes per square meter up to 265% compared to the unsprayed control, while treatment with CCC increased Leger grain yield by more than 10% in two of the 4 yr of this study. This yield increase was attributable to a slight increase in the number of grains per spike−1. Ethephon applied at ZGS 39 reduced plant height and lodging, but decreased yield by up to 27% because of reductions in the number of grains per spike, the main culm spike number, and/or weight per grain. These results indicate that in regions with a short crop‐growing season, where lodging is uncommon, early application of CCC or ethephon is not justified for grain production, and that caution must be taken when applying ethephon to spring barley at the currently recommended rate and stage for lodging control.
The Return of von Liebig's “Law of the Minimum”
Authors: Paris Q. 
Published: July 2010

AbstractThe development of optimal fertilizer recommendations requires a renewed collaborative effort between agronomists and agricultural economists. The purpose of this study is to emphasize the direction of this interdisciplinary effort in the area of crop response analysis. Using information from two separate experiments [corn (Zea mays L.) response to N and P fertilization and cotton lint (Gossypium hirsutum) response to N and irrigation water], it is shown that the best response model is a von Liebig specification, more commonly known as the law of the minimum. When the selection of a statistical specification is made among models that do not share the parameter space, hypothesis testing cannot be done by means of the familiar F‐test and likelihood ratio. The selection of the von Liebig specification (chosen against square‐root polynomial and Mitscherlich‐Baule models) is, thus, made on the basis of a rigorous statistical analysis using a nonnested hypothesis approach.
Performance of a Superior Bradyrhizobium japonicum and a Selected Sinorhizobium fredii Strain with Soybean Cultivars
Authors: Ravuri V. , Hume D. J. 
Published: July 2010

AbstractStrain 532C of Bradyrhizobium japonicum has outperformed other soybean [Glycine max (L.) Merr.] rhizobial strains in Ontario trials conducted with cv. Evans. Strain HH303 of Sinorhizobium fredii has proven effective with some Ontario cultivars. The objective of this research was to compare the performance of 532C with that of USDA 110, CB 1809, a three‐strain mixture, and HH303, by 16 commonly‐grown, early‐maturing soybean cultivars. Trials were conducted from 1988 to 1990 (only five cultivars were used in 1990) on soils that had low available N and had not grown soybeans previously. There were significant (P < 0.01) strain‐by‐genotype interactions for yield in all 3 yr and for seed protein content in 1988 and 1989, but interactions were small compared to main effects. Averaged over cultivars, strain 532C caused 11 to 17% higher seed yield than USDA 110 or CB 1809 in all 3 yr. Strain 532C appeared effective with all 16 cultivars tested. Strain 532C, used alone, caused higher average yields than the three strain mixture, which included 532C, only in 1988. The S. fredii strain HH303 caused consistently lower average yields than 532C, USDA 110, and the three‐strain mixture, but average yields with HH303 and CB 1809 were not different in 1988 and 1989. Cultivars with cv. Evans in their pedigree yielded well with HH303. There were strong positive correlations (r = 0.75−0.85) between seed yield and seed protein contents. Strain 532C supported higher seed yields than the three‐strain mixture at equivalent seed protein contents. Strain 532C was an effective N2 fixer with all cultivars tested and is now used in all soybean inoculants sold in Ontario.
Interrelationships among Turfgrasses, Clipping Recycling, Thatch, and Applied Calcium, Magnesium, and Potassium
Authors: Sartain J. B. 
Published: July 2010

AbstractThe influence of clipping return on bermudagrass thatch has not been resolved. Additionally, independent and combined effects of applied Ca, Mg, and K on bermudagrass growth and quality and thatch accumulation have not been clarified. To evaluate the influence of clipping return and applied Ca, Mg, and K on ‘Tifway’ bermudagrass (Cynodon dactylon (L.) Pers. × Cynodon transvaalensis Burtt Davy) and ‘Pennant’ perennial ryegrass (Lolium perenne L.) a 3‐y study was conducted at the Turfgrass Field Laboratory near Gainesville, FL, on an Arredondo loamy fine sand (Typic Quartzipsammets). A strip‐split‐plot factorial experiment with applied Ca, Mg, and K at 20 g m−2 representing the main plot and with clipping return or removal stripped across the main plots with three replications was employed. Bermudagrass clipping return did not affect overall mean thatch accumulation. Bermudagrass and perennial ryegrass clipping yields increased in response to clipping return. Bermudagrass quality was enhanced by the return of clippings, but ryegrass quality was not. Application of Ca and K did not influence thatch accumulation, while Mg did promote additional bermudagrass thatch. Application of K and Mg reduced Ca levels on plots receiving Ca to less than the extractable Ca level of the untreated plots. Ryegrass and bermudagrass quality was increased by the application of Mg on plots which had the clippings removed. Potassium and Mg application promoted bermudagrass clipping yield when clippings were removed. Soil Ca to Mg ratio did not influence the growth or quality of either bermudagrass or ryegrass.
Seeding Rate, Nitrogen Fertilization, and Irrigation Effects on Floral Meadowfoam Oil Yield
Authors: Jolliff G. D. , Seddigh M. , Norberg O. S. , Fiez T. E. 
Published: July 2010

AbstractIncreased rates of seeding and N fertilization have accounted for higher yields with new cultivars of several crops. Our objective was to evaluate the new meadowfoam cv. Floral (Limnanthes floccosa Howell subsp. grandiflora Arroyo) × Oregon Limnanthes ORL77‐84 (L. alba Hartw. ex Benth. subsp. alba). Combined effects of seeding rate (1.5, 4.0, and 6.5 million seeds ha−1), February applied N topdress rate (0, 80, and 160 kg ha−1), and irrigation (none, pre‐bloom, and pre‐ and post‐bloom) were evaluated near Corvallis, Oregon in 1987–1988 and 1988–1989. Seeding rate, N rate, and irrigation effects on all measured variables were independent of each other. Seed yield, seed oil content, and oil yield increased 45, 5, and 50%, respectively, while lodging did not increase as seeding rate increased from 1.5 to 6.5 million seeds ha−1. Increased flower number was the main reason for seed yield improvement when seeding rate was increased. Seed yield, seed oil content, and oil yield decreased slightly when N rate increased from 0 to 80 kg ha‐1, and dropped sharply at 160 kg N ha−1, with severe lodging. The highest average yields of seed (1684 kg ha−1) and oil (542 kg ha−1) were achieved with the combination of the highest seeding rate, lowest N fertilizer rate, and pre‐bloom irrigation.
Shade Induced Changes in Flower and Pod Number and Flower and Fruit Abscission in Soybean
Authors: Jiang Hongfei , Egli D. B. 
Published: July 2010

AbstractSeed number per unit area is important in determining yield in soybean [Glycine max (L.) Merr.]. Field and greenhouse experiments were conducted to evaluate the role of flowers per plant and flower and fruit abscission in determining pod and seed numbers. Two greenhouse experiments were conducted with the McCall cultivar [Maturity Group (MG) 00] and four cultivars [McCall, Hardin (MG I), Harper (MG III), Essex (MG V)] were used in field experiments in 1989 and 1990. The field experiments used either 0.38‐m (McCall and Hardin) or 0.76‐m rows (Harper and Essex) with a constant seeding rate of 26 seeds per meter. Shade cloth (63% in the greenhouse and 30 and 63% in the field) was placed over plants from R1 to maturity. Additional treatments in the greenhouse included shade from R1 to R4, R4 to R5, R5 to R6, and R4 to R8. Plants were harvested at maturity and flower and pod abscission was determined by counting both the scars marking the point of attachment of flowers and pods, and mature pods. Shade reduced pod numbers and the reductions were due to both increased flower and pod abscission and fewer flowers per plant. Both the number of nodes on the main stem and flowers per node were affected by the shade. Shade during any part of the R1 to R6 period reduced pod numbers in the greenhouse. These data indicate that environmentally induced variation in pod numbers in soybean is a result of both changes in flower and fruit abscission and the number of flowers produced.