bluuebunny/crossref_metadata_2025_split huggingface dataset:
Day‐Night Temperature Effects on Leaf Expansion and Height of Field‐Grown Corn
Authors: Benoit G. R. , Olness A. , Van Sickle K. A. 
Published: July 2010

AbstractThe effect of constant day/night, average daily, or instantaneous temperatures on plant growth has been extensively documented. Little work has looked at how plant growth under field conditions may be influenced by variations in the day/night temperature combinations experienced. Our objective was to evaluate the effect of day/ night temperature differences on daily corn (Zea mays L.) growth. To accomplish this, corn was grown with and without irrigation (four replications of three planting dates in 1983, 1984, and 1985) on a Hamerly clay (Aerie calciaquoll, fine‐loamy, frigid) at Morris, MN. Hourly soil and air temperature, weekly profile soil water content, and daily precipitation were recorded. Leaf area and plant height were measured daily from eighth leaf to 100% silking. Only plant size data from consecutive days of complete measurements were used with daily maximum and minimum temperatures to establish temperature‐growth rate relations. Leaf area and plant height prediction equations developed from stepwise multiple regression techniques were used to construct percent growth (leaf area and plant height) vs. maximum and minimum temperature response surfaces. Equations were developed for all possible combinations of planting date and irrigation level for each year and all years combined. Combined data showed general relations representative of those shown by individual data sets between percent growth and temperature. Plant height and leaf area predictive equations for combined data have highly significant r2 values of 0.72 and 0.54, respectively. The data shows that percent increase in plant size decreases over time as size at the start of any 24‐h‐growth period increases and that each daily maximum temperature has a successive apparent optimum night temperature for growth.
Soil Acidity and Liming Effects on Stand, Nodulation, and Yield of Common Bean
Authors: Buerkert A. , Cassman K. G. , de la Piedra R. , Munns D. N. 
Published: July 2010

AbstractThe area planted to common bean (Phaseolus vulgaris L.) has been declining in the Southern Mexican State of Chiapas. To determine factors limiting bean productivity in this region, on‐farm experiments were conducted at four locations. Soils were Acrisols (Ustults) at two sites and a Cambisol (Tropept) and Phaeozem (Ustoll) at the other two sites, with pH (H2O) of unlimed soil from 4.6 to 5.0. Insecticide application, genotype, and lime were treatments in a split‐plot design with a factorial combination of two genotypes and 0 or 2000 kg Ca(OH)2 ha−1 as subplots. Across sites, lime addition raised soil pH by 0.4 to 1.3 units, decreased Al saturation by 13 to 38%, and increased extractable Ca two‐to three‐fold. Mean yield without lime was 444 kg ha−1 ha. Insecticide and bean genotype had negligible effects on yield. Lime application resulted in a yield increase of 76 to 313% above unlimed controls across locations. Liming resulted in 40% greater shoot and 18% greater root dry weight, and also improved nodule weight per plant by 110% at early flowering. At maturity, plant density in limed treatments was 23% higher than in unlimed controls, and counts made during the season indicated that soil acidity factors inhibit seedling establishment. Liming also increased pod number per plant by 67%, seed number per pod by 18%, and seed weight by 7%. Increased yield from lime therefore resulted from better stand establishment, and increased seed yield per plant. Increased nodulation and N2 fixation may also contribute to the response to lime.
Domesticated and Wild Tepary Bean: Field Performance with and without Drought‐Stress
Authors: Federici C. T. , Ehdaie B. , Waines J. G. 
Published: July 2010

AbstractThe tepary bean (Phaseolus acutifolius A. Gray) is reputed to be heat and drought tolerant, but the literature contains little information on yield performance of tepary in different conditions. To fill this void, replicated field studies were conducted to measure and compare yield, seed protein concentration, and seed weight of 16 domesticated and eight wild tepary lines at the hot, dry location of Riverside, CA. Well‐watered and drought‐stressed conditions were set up in the summer of 1978. The experiment was repeated with six of the domesticated lines in the spring and summer of 1979. Significant differences were found among the wild lines and among the domesticated lines for the three traits measured. Mean yield and seed weight of wild teparies were 40 and 75% lower than those of domesticates, but mean protein concentration of the two groups was the same (27.6%). Moderate drought‐stress reduced the mean yield of teparies by 55%, but did not reduce protein concentration or seed weight. Seed yield showed a positive correlation with seed weight (r = 0.78), but a negative correlation with seed protein concentration (r = −0.75) in domesticated teparies.
Barley, Lentil, and Flax Yield under Different Intercropping Systems
Authors: Mandal Bijan K. , Mahapatra Susanta K. 
Published: July 2010

AbstractIntercropping is being adopted as a method of crop production throughout the developing tropics. The objective of this experiment was to assess how the productivity of intercrops was affected by the interaction of irrigation levels and mulches, compared to monocrops. Six‐rowed barley (Hordeum vulgare L.) was intercropped with lentil (Lens culinaris Medik) and flax (Linum usitatissimum L.) with two levels of irrigations [(i) zero and (ii) one irrigation applied 35 d after planting] and two levels of mulch [(i) no mulch and (ii) rice straw mulch at the rate of approximately 7 Mg/ha−1]. Monocrop of each species were also grown. Seed yield of the monocrops were higher than their intercrop yields. Intercropped barley yielded 73 to 81% of the yield to monoculture. Intercropped lentil yielded 30 to 34% of the yield of monoculture, whereas intercropped seed yield of flax ranged from 27 to 31% of monoculture. Yield increased from one application of irrigation ranged from 12 to 21% of zero irrigation. The increase in yield due to straw mulch was 11 to 17% higher over no mulch. The barley‐lentil intercrop recorded higher values of land equivalent ratio (LER) and monetary advantage (MA), and had higher intercropping advantage of area time equivalent ratio (ATER) than the barley‐flax intercrop.
Polyethylene Glycol Solution Contact Effects on Seed Germination
Authors: Emmerich William E. , Hardegree Stuart P. 
Published: July 2010

AbstractWhile polyethylene glycol (PEG) solutions have been used to control water potential in numerous seed germination investigations, there is concern that PEG solution‐seed contact may reduce seed germination. The PEG solution‐seed contact effect on seed germination was evaluated on four grass species: sideoats grama [Bouteloua curtipendula (Michaux) Torrey], buffelgrass [Cenchrus ciliaris L.], Lehmann lovegrass [Eragrostis lehmanniana Nees], and kleingrass [Panicum coloratum L.]. A water potential control system for seed germination was developed that controlled PEG (8000 mol. wt.) solution‐seed contact. Seeds were germinated on filter paper and cellulose membrane over the water potential range of 0.0 to −1.62 MPa. Buffelgrass and Lehmann lovegrass 21‐d germination and germination rate index (GRI) were not affected by PEG solution‐seed contact. Sideoats grama and kleingrass showed reduced germination and GRI without PEG solution contact on the cellulose membrane. The reduction was attributed to the hydraulic conductivity at the seedwater‐ membrane contact point which was influenced by PEG solution water potential and seed size and shape. Therefore, it was concluded EG solution‐seed contact does not reduce seed germination.
Modeling the Time Dependence of Nitrogen Uptake in Young Trees
Authors: Wallach D. , Loisel P. , Goffinet B. , Habib R. 
Published: July 2010

AbstractIn order to develop improved fertilization strategies for fruit trees, it is necessary to have a quantitative understanding of the dynamics of N uptake. This study was conducted to select a mathematical model for describing N uptake in young peach trees (Prunus persica (L.) Batsch). In 1985 young peach trees were grown outdoors in Avignon, France, in sand‐filled containers from late February to late September. At each of nine dates total tree N was measured by destructive sampling of three trees. The differences in total N between dates are related to N uptake. The models considered all take the form of a Michaelis‐Menten equation, with maximum uptake expressed as the product of total root weight and uptake efficiency. The models differ in that they express the efficiency factor as different order polynomial functions of time. The criterion used for selecting a best model was related to the squared error of prediction integrated over time. The value of the criterion was estimated for each model, and it was found that the model that expressed efficiency as a third‐order polynomial function of time had the smallest value of the criterion, and was therefore the model of choice. According to this model, N uptake efficiency increased from near zero in mid‐April to a maximum of 3.1 μg N/g root/d in late May, and then decreased again to near zero in late September.
Residual Nitrogen‐15 Recovery by Corn as Influenced by Tillage and Fertilization Method
Authors: Timmons D. R. , Cruse R. M. 
Published: July 2010

AbstractTillage systems that create different surface residue conditions may also affect the recovery of residual fertilizer N during subsequent growing seasons. This study evaluated the recovery of residual labeled N fertilizer in the soil by corn (Zea mays L.) for two tillage systems and two fertilization methods. Five atom % 15N‐enriched 28% urea‐ammonium nitrate solution (UAN) at 224 kg N ha−1 was either surface‐applied in the fall before any primary tillage or banded (knifed in) just before planting in the spring. Continuous corn was grown with either fall moldboard‐plow (MP) or ridge‐till (RT) systems. After the initial growing season, the recovery of residual labeled N in the soil by corn was determined for three consecutive growing seasons, and the soil profile was sampled periodically to measure residual ISN in the organic and inorganic pools. One year after labeled UAN application, from 16 to 27% of the initial I5N applied was found in the organic N pool and only 1% as inorganic N[NH4 + (NO2 + NO3)‐N]. After four seasons, residual 15N in the organic N pool ranged from 13 to 24%. Less than 0.5% remained as inorganic N. Regression analyses indicated that about 15N ha−1 yr−1 became available for both MP and RT systems with banded N, so the amounts were small. Total residual I5N recovery by corn grain plus stover for three seasons ranged from 1.7 to 3.5%, and was greatest for spring‐banded fertilizer (p = 0.01). Because the amounts of residual 15N utilized were too small to affect corn growth, this N source appears to be negligible when considering corn‐N needs.
Variable High‐Temperature Tolerance among Kentucky Bluegrass Cultivars
Authors: Howard Harold F. , Watschke Thomas L. 
Published: July 2010

AbstractThe tolerance to chronic high‐temperature stress varies greatly among Kentucky bluegrass (Poa pratensis L.) cultivars. This study of photosynthesis characteristics was conducted to determine whether such traits differ among cultivars and contribute to variable hightemperature tolerance. High‐temperature‐tolerant cultivars exhibited superior growth rates at 30 °C but growth rates were similar among cultivars at 10 °C. At 10 °C, fructosan comprised an approximately two‐fold larger portion of the plant dry weight than at 30 °C, however nonstructural carbohydrate fractions did not differ among cultivars. Under each experimental temperature, the sum of glucose, fructose, and sucrose fractions was approximately the same, though the relative concentrations were temperature dependent. Apparently fructosan served as a buffer fraction that allowed the sum of the other nonstructural fractions to remain constant. Photosynthetic response to increased leaf temperature was similar among cultivars but differed among acclimation temperature regimes. Net photosynthetic rates varied by as much as one‐third among cultivars, however, with a positive relationship between net photosynthetic rates and high‐temperature tolerance. These differences were not attributable to differential CO2 diffusive resistances. This evidence indicated that high‐temperature‐tolerant cultivars were capable of sustaining superior net photosynthetic rates under high but not low temperature conditions. It is suspected that cultivar differences in photosynthetic electron transport capacity may have caused this trend.
Witchweed Management by Sorghum‐Sudangrass Seed Size and Stage of Harvest
Authors: Bebawi Faiz F. , Mutwali Elnasri M. 
Published: July 2010

AbstractCareful cultural management of field crops has become imperative in countries where chemical measures are not economically feasible. The occurrence of the endemic parasitic witchweed [Striga hermonthica (Del.) Benth] in production fields of sorghum‐sundangrass hybrid [Sorghum bicolor (L.) Moench ✕ S. sudanense Stapf. cv. Piper], Pioneer brand hybrid 988 (coded P988), is one example that requires such procedures. Study objectives were to relate: (i) P988 seed size (large and small) to witchweed germination, P988 root and shoot length, and weight and (ii) P988 seed size and harvest growth stage to P988 greenchop yield and sucrose content at three initial and subsequent P988 harvests at boot stage, late bloom stage, and maturity in witchweed‐infested fields. Seedlings of P988 grown from small seed had significantly shorter shoots but longer roots compared to those from large seed. Witchweed germination was not signficiantly affected by seed size of P988 but was postively correlated to P988 root length and root dry weight. Seed size of P988 had no significant effect on forage greenchop yield and forage sucrose of P988 at all harvests. Delaying initial harvest of P988 increased witchweed shoot dry weight with time and equated total yields, but reduced the quality of greenchop at late bloom and maturity. Delaying second and third harvests of P988 to maturity significantly increased greenchop yield of P988. Forage sucrose at maturity stage of second and third harvests exceeded forage sucrose at maturity of first harvest by 106 and 60%, respectively. Witchweed shoot dry weight was positively correlated with forage sucrose of P988. Growing small seeded P988 reduced witchweed incidence and sustained P988 yields when combined with harvesting at the boot stage on first harvest and at maturity of later harvests on witchweed‐infested soils.
Cotton Response to Starter Fertilizer Placement and Planting Dates
Authors: Guthrie D. S. 
Published: July 2010

AbstractEffect of planting date on cotton (Gossypium hirsutum L.) response to side‐banded starter fertilizer has not been well documented. Consequently, field studies were conducted in four North Carolina environments to examine the response of cotton to placement of starter fertilier at three planting dates. Cotton planted prior to 5 May (Early), mid‐May (Mid), and late‐May (Late) on a Norfolk loamy sand (fine‐loamy, siliceous, and thermic Typic Kandiudults) and Craven fine sandy loam (clayey, mixed, thermic Aquic Hapludults) received broadcast or side‐banded applications of ammonium polyphosphate at the rate of 17 and 57 kg ha−1 of N and P2O5 respectively. Fertilizer placement had minor effects on plant population. Planting period effects on plant population could not be attributed to heat unit accumulations. Flower production during the first 3 wk of bloom varied with planting period and environment Mid‐ and late‐planting decreased average lint yields across the four environments by 31 and SO%, respectively. Lint yield was increased 9% by side‐banded fertilizer placement. Significant planting period ✕ fertilizer placement interactions were not observed for plant population, flower production, and lint yield. This indicates that applying side‐banded starter fertilizer can benefit producers irrespective of planting date.
Establishment of Two Bermudagrasses in Three Soil Environments
Authors: Mueller J. P. , Green J. T. , Nelson L. A. , Hall J. V. 
Published: July 2010

AbstractTifton 44 hybrid bermudagrass [Cynodon dactylon (L.) Pers.], has been reported to be more cold tolerant and to give better animal gains than the hybrid Coastal. It has been observed that Tifton 44 has not established as rapidly as Coastal, frequently taking 2 to 3 yr to achieve complete ground cover. The objective of this work was to determine and quantify differences in the field establishment of Coastal and Tifton 44 grown at three locations for 2 yr on clayey, kaolinitic, thermic Typic Hapludult (Cecil and Mayodan) and loamy, siliceous, thermic Grossarenic (Blanton) soils in North Carolina. A single row of sprigs was set in the center and the length of each 3.1‐ by 6.2‐m plot. Establishment effects were measured by weekly counts of the number of tillers/stolons intercepting a series of transect lines spaced at 0.15‐m intervals on both sides of the sprigged row, and by harvesting the forage produced at the end of the season in 0.30‐ by 6.1‐m increments from the center to the border of each plot. Two establishment indices were developed as the response variables from the transect count data. Analyses of variance were conducted on yield, establishment indices, and on spring ground cover estimates. Yield of forage and establishment characteristics were similar for Coastal and Tifton 44 on the Mayodan soil, but Coastal established more rapidly and produced more forage than Tifton 44 on the Cecil soil in both years of the trial and on the Blanton soil during the first year. In three of six trials, Tifton 44 would have required a 0.3‐ to 0.6‐m row spacing to equal the coverage obtained by Coastal in a 0.9‐ to 1.2‐m row spacing.
FORTRAN Graphics Library for PC‐Based Crop Simulation Models
Authors: Hodges Tom 
Published: July 2010

AbstractA graphics library is presented for PC‐based crop growth simulation models written in the FORTRAN programming language. The library can be incorporated into simulation models with only minor programming. It allows the user to graphically plot simulated variables and measured values on the computer screen while a model is running. Graphs can also be sent to an output device such as a plotter, printer, or slide maker. Procedures for installing the library in a simulation model are described with the SIMPOTATO potato model as an example. The library is a module that can be quickly and easily added to FORTRAN simulation models by even relatively inexperienced programmers.
Reproductive Morphology of Five Kentucky Bluegrass Cultivars
Authors: Rhoads J. L. , Dunn J. H. , Minner D. D. , Hunt K. L. 
Published: July 2010

AbstractA problem associated with plant growth retardant applications in Kentucky bluegrass, Poa pratensis L., is the application window for effective seedhead and vegetative growth suppression. Theoretically, the optimum timing for growth retardant applications would be just prior to the peak growth period in spring and before the inflorescence becomes visible above the youngest leaf. The objective of this field study was to determine if time of primordia initiation as an indicator of inflorescence development is consistent in selected Kentucky bluegrass cultivars in successive growing seasons. Initiation of inflorescence primordia was determined by randomly sampling and dissecting primary tillers of each cultivar during the late winter‐early spring and observing under a dissecting microscope. Our research showed that dates marking a transition from vegetative toward a predominately reproductive growth habit varied significantly among Kentucky bluegrass cultivars in both years. Also, one of the six cultivars, Kenblue “low maintenance” was not in a similar reproductive condition on several observation dates occuring in the same calendar week of 1986 compared with 1987. These results, based on our 2‐yr study, show that reproductive variation exists among Kentucky bluegrass cultivars, and that some cultivars may not develop inflorescences annually within calendar date application windows for growth retardants with much predictability.
Third‐Year Forage Yield Testing in Tall Fescue is Not Cost Effective
Authors: Nepal Pratima , van Santen Edzard 
Published: July 2010

AbstractSmall plot cultivar testing is an integral part of the decision‐making process in agronomic research relating to release and production recommendation of cultivars. The objective was to evaluate duration of tall fescue (Festuca arundinacea Schreb.) cultivar trials with respect to the information obtained. Tall fescue performance data from 12 states were obtained from eight different sources. Coefficients of determination were obtained from regressing three single‐year and two 2‐yr yields on 3‐yr yield for each trial. First‐year yields explained from 14 to 90% of the variation among cultivars after 3 yr of testing. Single‐year trials or single‐year data from multi‐year trials are inadequate because of many low coefficients. Two‐year yields explained from 0 to 100% of the differences among cultivars after 3 yr of testing. Twelve percent of the trials had coefficients ≤0.80 when the first two production years were used in the analysis compared to 38% when the last two years of a 3‐yr trial were used. Therefore, a trial duration of two production years is the better alternative to taking data during the last two production years of a 3‐yr trial. It is concluded that a trial duration of more than 2 yr is an ineffective use of scarce resources if total dry matter production is the only factor considered.
Nitrogen Fertilization of Tall Fescue‐Birdsfoot Trefoil Mixtures
Authors: Hoveland C. S. , Richardson M. D. 
Published: July 2010

AbstractIn mixtures with birdsfoot trefoil (Lotus corniculatus L.), tall fescue (Festuca arundinacea Schreb.) growth during early spring and autumn in north Georgia is limited. A study was conducted to determine if supplemental N fertilizer could extend the productive season of tall fescue‐birdsfoot trefoil mixtures. Field experiments were conducted for 3 yr in the Mountain and Piedmont regions of Georgia. Mixtures grown included ‘AU Triumph’ tall fescue with ‘Fergus’ or ‘AU Dewey’ birdsfoot trefoil and tall fescue alone, all with N rates of 0, 56, or 112 kg ha−1 in February, or 56 kg ha−1 in February and September. The grass‐legume mixture at 0 N had total forage yields similar to tall fescue + 112 kg N ha−1. Spring production of tall fescue‐birdsfoot trefoil mixtures was increased 50 to 114% with 56 kg N ha−1. Autumn production was increased 80 to 200% with 56 kg N ha−1 in September. The N concentration of non‐N‐fertilized tall fescue increased 24% when grown with birdsfoot trefoil. Apparent N2 fixation of birdsfoot trefoil grown with tall fescue ranged from 79 to 137 kg N ha−1 during a good rainfall year. Birdsfoot trefoil apparently did not fix sufficient N for cool season growth of tall fescue, so that application of N in February and again in September extended the productive season of tall fescue‐birdsfoot trefoil mixtures.