bluuebunny/crossref_metadata_2025_split huggingface dataset:
Semidwarf and Conventional Height Sunflower Performance at Five Plant Populations
Authors: Majid Hashim R. , Schneiter A. A. 
Published: July 2010

AbstractSemidwarf sunflower (Helianthus annuus L.) hybrids have been developed by several commercial companies and could be grown on large hectarage in the future. Information on the total water use and other agronomic traits of the semidwarf (SD) types as they compare to conventional or standard height (SH) sunflower is not available. This field study was conducted to: (i) determine total water use (TWU) and water use efficiency (WUE) of SD and SH sunflower, and (ii) determine the effect of plant population on harvest index (HI), stalk diameter, plant height, and leaf number of both plant types. Two experimental SD and two SH hybrids of similar maturity from the Cargill and Sigco Research breeding programs were grown at dryland populations of 32 123, 49 420, 66 717, 84 014, and 101 311 plants/ha over a 3‐yr period (1982‐1984) at Fargo, Carrington, and Prosper, ND. Data were collected and calculated for nine characteristics in this study. Total water use and WUE data were determined only at a plant population of 49 420 plants/ha. All hybrids evaluated had similar TWU, WUE, HI, and stalk diameter. The Cargill SH had the fewest number of leaves. It was concluded that reductions of plant height do not affect internode number, TWU, and HI. Other agronomic traits as a response to plant population were similar for both plant types, and observed differences were often due more to genotype origin than to plant type. Increasing plant population reduced HI, grain yield per plant, biomass per plant, and stalk diameter. Increasing plant population increased plant height of all hybrids except the Sigco SD.
Spring Wheat and Barley Responses to Ethephon
Authors: Simmons S. R. , Oelke E. A. , Wiersma J. V. , Lueschen W. E. , Warnes D. D. 
Published: July 2010

AbstractEthephon [(2‐chloroethyl) phosphonic acid] has recently been introduced in North America as a regulator to control lodging in cereals. A 3‐yr study (1983‐1985) was conducted to determine how widely grown spring wheat (Triticum aestivum L.) and spring barley (Hordeum vulgare L.) cultivars in the North Central United States responded to ethephon. Nine randomized complete‐block, split‐plot experiments with wheat, and seven with barley, were conducted at the Crookston (soil classification, Aeric Calciaquoll), Morris (Aeric Calciaquoll), St. Paul (Typic Hapludoll), and Waseca (Aquic Hapludoll) Experiment Stations in Minnesota. Ethephon was applied at a rate of 0.42 kg a.i. ha−1 in all years as well as 0.28 kg a.i. ha−1 in 1985. When lodging occurred, ethephon treatment at either rate lessened its severity. Ethephon shortened crop height, more so when applied at the higher rate. Effects of ethephon on grain yields varied from significant reductions (average 13% for wheat, 9% for barley) to significant increases (average 12% for wheat, 13% for barley). Increases were most common when control plots lodged, although higher yields in response to reduced lodging were not obligatory. When lodging did not occur, ethephon treatment tended to result in reduced yields. Among barley cultivars, ‘Robust’ was most likely to exhibit reduced yields. Genotypic variability for ethephon sensitivity among wheat cultivars was less evident. In most experiments, ethephon treatment lowered kernel numbers per spike or mass per kernel. We conclude that ethephon use is most reasonable when the production practices followed, or environmental conditions, assure the likelihood of significant lodging. Further research investigating cereal responses to lower ethephon rates, as well as interactions between ethephon and plant stress, is needed.
Random Stand Deficiency and Replanting Delay Effects on Soybean Yield, Yield Components, Canopy, and Morphological Responses
Authors: Willmot D. B. , Pepper G. E. , Nafziger E. D. 
Published: July 2010

AbstractPoor soybean [Glycine max (L.) Merr.] emergence presents difficult replanting decisions. Most plant population research has involved deficient stands with even distribution rather than the more commonly encountered random gap distribution. The objective was to provide guidelines for making profitable replanting decisions. Field experiments were conducted in 1984 and 1985 to compare growth parameters and seed yield of an adapted cultivar in northern, central, and southern Illinois at 42,40, and 38° N Lat, respectively. Initial and delayed (21 d) plantings were made in rows 0.76 m apart. Two plant densities (291 550 and 202 350 plants ha−1) and five random stand deficiencies levels (0 to 60%) were established within each planting. The largest effect on seed yield was caused by random stand deficiency followed by environment and planting date. Stands with randomly imposed 0.31 m gaps totaling 40 and 60% of the plot areas resulted in 10.8 and 21.1% yield reductions, relative to uniform stands in the initial planting, respectively. Replanting delays resulted in an average relative yield loss of 9.0%. Photosynthetic photon flux density measurements were made when the initial planting reached R5 and were expressed as percent light interception (PLI). The PLI at R5 was not related to the 9.0% yield loss due to replanting delay. At the 60% stand reduction level the low plant density mean yield was 6.2% less than the high plant density mean over both plantings. Seed number per plant ranged from 63.9 in replanted full stands to 195.1 in the most deficient initial planted stands. Seed weight effects were minimal and inconsistent. The PLI decreased quadratically with increasing stand reductions from 92.5% in full stands to 80.4% in stands reduced by 60% (over all other factors). Relative yield (RY) was regressed on PLI as follows: (i) initial planting: RY = 39.65 + 1.4781 PLI (r2 = 0.941, P < 0.01); and (ii) Delayed replanting: RY = 47.75 + 1.4598 PLI (r2 = 0.944 P < 0.01). In most environments only stand reductions of over 50% could be justifiably replanted. The results provide guidelines for decisions of whether or not to replant, based on expected yield losses due to irregular initial stand emergence compared with expected losses due to replanting delay.
Simulation of Maize Phenology
Authors: Grant R. F. 
Published: July 2010

AbstractIn order to perform reliably, crop simulation models require an accurate treatment of crop phenology. A procedure for simulating maize (Zea mays L.) phenology was developed as a subroutine for a maize growth model which ran on an hourly time step. Maize development is simulated from hourly rates of leaf initiation and appearance during three phases of organ differentiation: juvenile, inductive, and reproductive. Leaf initiation occurs during the first two phases, and is terminated by tassel initiation, at which time final leaf number is established. The timing of tassel initiation during the inductive phase is determined by photoperiod and temperature effects on leaf number. The reproductive phase begins at tassel initiation and ends at silking shortly after the appearance of the last leaf before the tassel. Functions used to calculate leaf numbers and rates of leaf initiation and appearance are taken from published results of phytotron studies. Model estimates of leaf number, and of dates of tassel initiation and silking were compared with those observed from a maize phenology trial conducted at five sites in North America. Estimated dates of silking were also compared with those from other data sets. Estimated leaf numbers were usually within one of those observed at all but one site in the phenology trial, where leaf numbers were overestimated by as much as four leaves. Estimated dates of tassel initiation and silking were usually within 5 d of observed dates except at the warmer sites in Texas where estimated dates preceded observed dates by 5 to 15 d. The data suggest that high temperature acclimation may have resulted in slower rates of development than those predicted at some of the warmer sites. Chilling, acclimation, and other effects on phenology not present in phytotron studies will have to be considered further before the results of these studies may be widely used in models of maize phenology.
Yield, Dinitrogen Fixation, and Aboveground Nitrogen Balance of Irrigated White Lupin in a Mediterranean Climate
Authors: Larson K. J. , Cassman K. G. , Phillips D. A. 
Published: July 2010

AbstractAs an initial effort to evaluate irrigated white lupin (Lupinus albus L.) in California, we evaluated seed yield, N2 fixation, and the N economy of this crop in a 2‐yr field study. Treatments were arranged in a completely randomized block design and included two (Year 1) or three (Year 2) lupin cultivars each either (i) inoculated with Bradyrhizobium sp. (Lupinus) and no N fertilization, (ii) with neither inoculation nor N fertilization, or (iii) with N applied at 200 kg N ha−1 (Year 1) or 275 kg N ha−1 (Year 2). Mean seed yield from inoculated treatments was 5.73 Mg ha−1 with 46.4 g N kg−1 in Year 1, and 4.79 Mg ha−1 with 48.9 g N kg−1 in Year 2. Seed yield was similar with or without inoculation, but total dry matter and N accumulation were highest in inoculated treatments. Nitrogen fertilization did not increase yield or N accumulation above that of inoculated treatments. Estimates of N2 fixation by the N difference method ranged from 193 to 247 kg ha−1. Symbiotically fixed N represented 67 to 78% of total aboveground plant N, but the N harvest index ranged from 0.80 to 0.91, and thus, total seed N exceeded the quantity of N2 fixed by 23 to 68 kg N ha−1. Despite the lack of a net increase in soil N after seed removal, the yield potential and N2 fixation exhibited by white lupin during the cool‐season are favorable attributes for a winter annual protein crop in a mediterranean climate.
Cotton Canopy and Drying Effects on Runoff During Irrigation with Moving Sprinkler Systems
Authors: Ben‐Hur M. , Plaut Z. , Shainberg I. , Meiri A. , Agassi M. 
Published: July 2010

AbstractSelf‐propelled moving sprinkler irrigation systems (MSIS) have become increasingly popular in recent years. However, high amounts of runoff were measured from fields during irrigation with MSIS. Surface runoff from a silt loam loess soil (Calcic Haploxeralf) and a clay vertisol soil (Typic Chromoxerert) under different irrigation management was studied in field plots (3 m2, with a slope of about 2%). The experimental fields were irrigated with a lateral MSIS (spray nozzle) with a discharge of 650 L m−1 h−1 and an average water application rate of about 100 mm h−1. The percent surface runoff in loess and vertisol soils was 22 and 0%, respectively, under straw mulch conditions vs. 53 and 39% under unmulched conditions. The greater runoff was due mainly to crust formation at the soil surface. The impact energy of the irrigation water drops caused the soil surface structure to break down and form a surface crust with a resultant decrease in the infiltration rate (IR). Coverage of the loess‐crusted soil surface by the cotton (Gossypium hirsutum L., cv. Acala SJ‐2) canopy did not reduce the percent runoff from weekly irrigations of 50 mm. A drying period of 7 d between water applications did not break the crust, which was formed at the beginning of the irrigation season, and the large amount of runoff (50%) remained constant until the end of the season. Conversely, 14 to 18 d of drying caused a breakage of the crust, resulting in increased IR. Under these conditions, the cotton canopy prevented the reformation of the crust during consecutive irrigations and the runoff decreased to 15% at the end of the season. When the amount of water per irrigation was 15 to 30 mm and the drying period was 2 to 3 d, the runoff value was about 20%. This low percentage apparently resulted from insufficient amounts of water necessary to form a fully developed crust.
Serological Distribution of Bradyrhizobium japonicum from U.S. Soybean Production Areas
Authors: Weber D. F. , Keyser H. H. , Uratsu S. L. 
Published: July 2010

AbstractBradyrhizobium japonicum strains are widely distributed throughout U.S. soybean [Glycine max (L.) Merr.] production areas. Many surveys of local or regional areas have been conducted, but none has covered all production states or related their distribution to strains previously used in commercial inoculants. A total of 767 isolates of root nodule bacteria, from 79 locations in 27 states of the major soybean production areas, were analyzed with 15 antisera to determine serological composition. Eight serogroups represented 63% of the isolates, 19% of the isolates had double reactions, and 15% did not react. The predominant serogroup was 123, which represented 24% of the isolates tested, followed by serogroup 31 with 14%. The other isolates were evenly distributed among serogroups. The relationship between the pattern of distribution of the isolates around the USA and strains used in commercial inoculants is discussed. Knowledge of isolates that constitute an indigenous Bradyrhizobium population should be helpful in selecting more effective strains for inoculants.
Sample Intensity and Timing for Detecting Acremonium coenophialum Incidence in Tall Fescue Pastures
Authors: Thompson R. W. , Fribourg H. A. , Reddick B. B. 
Published: July 2010

AbstractPastures of tall fescue (Festuca arundinacea Schreb.) infected with the endophytic fungus Acremonium coenophialum Morgan‐Jones and Gams have been associated with livestock disorders known collectively as fescue toxicosis. Destruction of infected (E+) fescue pastures and reestablishment with endophyte free (E−) seed is beneficial for eliminating fescue toxicosis. However, since management decisions must be based on knowledge of A. coenophialum incidence, sampling of pastures should provide information about fungal incidence with accuracy. Two experiments were conducted to compare sampling methods. In the fist experiment, eight 4‐ha, 2‐yr‐old pastures established with seed mixtures ranging from near 0 to more than 70% E+ were sampled. A transect method and a stratified random sample based on area at an intensity of 23 tillers ha−1 were used. In the second experiment, four 20‐yr‐old, 2‐ha E+ pastures were sampled at monthly intervals for 2 yr. Stratified random sampling at 41 samples ha−1 and simulated transects using the same data were used. Samples were assessed for E+ status using Protein A enzyme‐linked immunosorbent assay (PAS‐ELISA). In the first study, observed E+ incidence in two pastures increased from 15 or 30% to about 60%, respectively, during the 2‐yr. Reasons for this increase are not known. The other pastures, established with 0,45, 60, and 75% E+ seed had only small increases in E+ incidence. Significant E+ incidence could be detected in the second study at any time during the year. Six to eight samples ha−1 were adequate for characterizing A. coenophialum status. Transect and stratified random samplings gave similar E+ estimates.
Trend Analysis to Improve Efficiency of Agronomic Trials in Flue‐Cured Tobacco
Authors: Bowman D. T. 
Published: July 2010

AbstractThe desire to improve statistical evaluation efficiency in flue‐cured tobacco (Nicotiana tabacum L.) cultivar trials and the inconvenience of restricted entry numbers in incomplete block designs prompted an investigation into a statistical procedure known as the trend analysis. The objective was to determine relative efficiency of the trend procedure compared to the randomized, complete block design by examining error variances from both analyses of variance. Eleven traits on all entries of the North Carolina Official Flue‐Cured Tobacco Variety Trials were examined at five environments. Relative efficiency of trend compared to the randomized, complete block design ranged from 97 to 161% for traits and environments. Only one trait, number of ground suckers, showed no improvement in precision (101%) from trend analysis while quality indicators ($/kg and grade index) showed the greatest improvement (126 and 124%) when averaged for all environments. The data revealed that blocking may be effective for one trait and not another.
Allelopathy of Crop Residues Influences Corn Seed Germination and Early Growth
Authors: Martin V. L. , McCoy E. L. , Dick W. A. 
Published: July 2010

AbstractCrop residues produce alleochemicals that may inhibit corn [Zea mays (L.)] seed germination and early growth. Studies were conducted in which residues of corn, soybean [Glycine max (L.) Merr.], oat [Avena sativa (L.)], and mixed grass hay were extracted under N2 gas or air. Organic debris was removed and half of each extract was filter sterilized. Corn seeds were incubated in the extracts for 96 h at 25 °C. Percent germination, and lengths of coleoptile, radicle, and secondary roots were measured. Residues extracted under N2 gas or air did not differ significantly in their toxicity. Nonsterile residue extracts decreased germination to 74% for soybean and oat straw and 27% for corn and hay residues. Sterile extracts did not affect germination. Nonsterile soybean and oat extracts did not reduce coleoptile lengths but did reduce radicle and secondary root lengths by 34% compared to the water treatment. Sterilized extracts reduced radicle and secondary root lengths by 63%. Nonsterile corn and hay extracts reduced coleoptile lengths by 42% and radicle and secondary root lengths by 81%. A second extraction was performed by incubating the residues without aeration at 25 and 0.5 °C. Seed germination for treatments with nonsterile extracts obtained at 25 °C were similar to those for nonsterile extracts of Exp. 1. Extraction at 0.5 °C and filter sterilization also improved germination. Soybean and oat extracts did not strongly inhibit coleoptile lengths; however, a 61% reduction occurred in radicle and secondary root lengths for the sterilized, 0.5 °C extract. Corn and hay residues were generally more inhibitory to coleoptile, radicle and secondary root lengths; however, no consistent effects were observed from temperature and sterilization treatments.
Effects of Nitrogen, Dicyandiamide, and Tillage on Cotton Nitrogen Concentration and Yield
Authors: Gordon W. B. , Rickerl D. H. , Touchton J. T. 
Published: July 2010

AbstractConservation tillage has the potential to increase N leaching from sandy soils by increasing water infiltration. The nitrification inhibitor dicyandiamide (DCD) can reduce this risk, but cotton (Gossypium hirsutum L.) may be sensitive to DCD. Field studies were conducted at the E.V. Smith Research Center in Macon County, AL on a Norfolk soil (fine, loamy, siliceous, thermic Typic Paleudult) to determine the effects of DCD on cotton N concentration and yield of conventional and strip‐till cotton. Nitrogen treatments included four preplant N rates (0,67,100, and 134 kg ha−1) with and without DCD (10% of N rate). Leaf N concentration was generally greater in treatments receiving N fertilizer than no N; however, regressions between N concentration and N fertilizer were not always significant. Whole plot effects on yield due to tillage were significant. Optimum N rate for seed cotton production was 67 kg ha−1 N in 1984 and ranged between 100 and 134 kg ha−1 N in 1985 and 1986. The application of DCD decreased yields by 30% in 1984. At the 134 kg N ha−1 rate in 1985, DCD increased yields by 24%. In 1986 seed cotton yields in the strip‐till treatment receiving 134 kg ha−1 N were 20% less with DCD than without. It is concluded that application of DCD is beneficial, with typical rainfall patterns, if high rates (13 kg ha−1) are used. However, if rainfall is less than the historical average during first square to first bloom stage, DCD application has little effect or is detrimental to seed cotton yield.
Topical Cellulase Application Effects on Tall Fescue Digestibility
Authors: Forwood J. R. , Sleper D. A. , Henning J. A. 
Published: July 2010

AbstractTwo studies were conducted to assess the effects of topically applying a prepared cellulase solution (PCS) as a forage pretreatment to increase digestibility of tall fescue (Festuca arundinacea Schreb.). Fall regrowth and stockpiled tall fescue were harvested from the field (Mexico silt loam: fine montmorillonitic mesic Udollic Ochraqualf) and studied in laboratory Exp. 1 and 2, respectively. Experiment 1 involved topical application of 40 mL of PCS to 100 g (on a dry‐matter basis) dried and fresh leaf material that had either been chopped or remained whole. Further treatments involved 1‐, 6‐, or 12‐h drying times post‐application and freezing to curtail enzymatic activity or no freezing. Experiment 2 involved whole and chopped fresh leaf material with a surfactant treatment added and post‐application drying times altered to 1,12, 24, and 48 h. In vitro dry matter digestibility (IVDMD) of tall fescue was significantly increased (28 g kg−1) by topical application of PCS in both experiments. Allowing longer exposure time of herbage to PCS was not an advantage. Addition of a surfactant to PCS decreased IVDMD (36 g kg−1) but increased IVDMD (14 g kg−1) when PCS was not applied. Allowing the PCS to dry on herbage for 1‐, 12‐, and 24‐h post‐application resulted in significant IVDMD increases compared to no PCS (22,27, and 31 g kg−1, respectively) while PCS application most benefited IVDMD for 24 h. Scanning electron micrographs revealed cuticular disruption on leaf blades which may be at least partially responsible for increased IVDMD of PCS‐treated samples. These studies indicated that topical PCS treatment can extend existing forage supplies. Further studies under field conditions and animal trials are needed.
Maize Leaf Number Sensitivity in Relation to Photoperiod in Multilocation Field Trials
Authors: Bonhomme R. , Derieux M. , Kiniry J.R. , Edmeades G.O. , Ozier‐Lafontaine H. 
Published: July 2010

AbstractThe photoperiodic response of maize (Zea mays L.) determines the total number of leaves (LN). Knowledge of this is important for modeling phenology and for describing cultivar adaptation. The objective of this research was to evaluate artificial extension of photoperiod for field‐grown maize as a method of quantifying photoperiodic sensitivity. The LN response was quantified using data from six diverse maize cultivars grown at two field locations where natural photoperiods were artificially extended by 1.3 h to 7.3 h. These responses were then compared with LN observed in a field experiment of the same cultivars grown at 11 diverse latitudes. The relative ranking of photoperiod sensitivity among cultivars was similar for the two groups of experiments, although observed sensitivity was occasionally greater in artificial light experiments than in multilocation experiments. Photoperiod sensitivity was greater for the tropical than for the temperate cultivars, with mean sensitivities of 1.91 and 0.49 leaves h−1, respectively. The LN in tropical cultivars was reduced by 0.5 to 2.0 leaves plant−1 for every min d−1 increase in rate of change of photoperiod during the photoperiod‐sensitive stage. Artificial extension of daylength by lights mounted in the field appears to be an effective and efficient means of screening maize cultivars for photoperiodic sensitivity.