bluuebunny/crossref_metadata_2025_split huggingface dataset:
Pooling Experiments Over Time to Quantify the Dynamics of Dryland Winter Wheat Yield Response
Authors: Burt Oscar R. 
Published: July 2010

AbstractThis research had a dual purpose: (i) statistical estimation of winter wheat (Triticum aestivum L.) yield response as a function of plant available water and applied N fertilizer from an 8‐yr experiment in north‐central Montana and (ii) illustration of the modeling methods that are appropriate in this type of research. Summer‐fallowed and re‐cropped treatments were pooled to obtain an indirect estimate of the extra amount of N made available by summer fallow, as well as to improve the implicit experimental design by providing the necessary variation in plant available water, particularly soil water at seeding. The statistical model was nonlinear regression with an error components disturbance term entering multiplicatively. A new flexible functional form is presented for crop response; it is a polynomial generalization of the Mitscherlich single‐factor equation. A major task was to validate the regression model by considering various types of specification errors, such as accounting for all concomitant factors associated with pooling the experiments over time. Mineralized N during summer fallow was found to be a negatively sloped linear function of precipitation during the fallow period; the average amount was 24.5 kg ha−1. Nitrogen and water have strong interactions in shaping the yield response surface, and at high levels of both factors, more of either depresses yield. The depressing effect of N on yield at very low levels of water was clearly discerned.
Sod Regrowth of St. Augustinegrass after Preemergence Herbicide Application
Authors: McCarty Lambert B. , Porter D. Wayne , Colvin Daniel L. 
Published: July 2010

AbstractSt. Augustinegrass [Stenotaphrum secundatum (Walt.) Kuntze] sod production involves stolon regeneration from strips left from the previous harvest. Field studies were conducted to evaluate stolon regrowth and rooting following preemergence application of herbicides. Herbicides evaluated were atrazine [6‐chloro‐N‐ethyl‐N'‐(1‐methylethyl)‐1,3,5‐triazine‐2,4‐diamine], dithiopyr [S,S‐dimethyl 2‐(difluoromethyl)‐4‐(2‐methylpropyl)‐6‐(trifluoromethyl)‐3,5‐pyrldinecarbothioate], isoxaben [N‐[3‐(1‐ethyl‐l‐methylpropyl)‐5‐isoxazolyl]‐2,6‐dimethoxybenzamide], metolachlor [2‐chloro‐N‐(2‐ethyl‐6‐methylphenyl)‐N‐(2‐methoxy‐1‐methylethyl) acetarnlde], oxadiazon [3‐[2,4‐dichloro‐5‐(1‐methylethoxy)phenyl]‐5‐(1,1‐dimethylethyl)‐1,3,4‐oxadiazol‐2‐(3H)‐one], pendimethalin [N‐(1‐ethylpropyl)‐3,4‐dimethyl‐2,6‐dinitrobenzenamine] and the combination of metolachlor plus atrazine. Acceptable ‘Floratam’ St. Augustinegrass color was noted following all treatments. Twelve to 24% of the stolons were unrooted 4 to 8 mo after application following treatment with 0.8kg a.i. ha−1 dithiopyr. Five to 22% of the stolons were unrooted 8 mo after treatment with isoxaben at 1.1 kg ha−1 and pendimethalin at 2.2 kg ha−1. Data collected after 8 mo showed stolon rooting to be similar to the untreated for all treatments. Turfgrass density was unaffected or slightly improved (≈25%) by herbicide treatment and was highest with oxadiazon, metolaehlor, and metolachlor plus atrazine treatments. Neither turfgrass tensile strength nor root dry weight was reduced 14 mo after treatment with any of the herbicides evaluated. Although shortterm (2 to 4 mo) negative effects followed dithiopyr, isoxaben, and pendimethalin treatments, long‐term (≥ 8 mo) effects were transient.
Nonparametric Analysis of Cultivar Performance Trials: Experimental Results and Comparison of Different Procedures Based on Ranks
Authors: Hühn Manfred , Léon Jens 
Published: July 2010

AbstractCultivar performance trials are usually analyzed by analysis of variance techniques. In the field of practical applications, the required simplifying assumptions may often not be fulfilled. Nonparametric methods based on ranks avoid this difficulty and provide a viable alternative to parametric procedures. The objective of this study was to compare four nonparametric procedures (Bredenkamp, Hildebrand, Kubinger, and van der Laan‐de Kroon) and the parametric analysis of variance with each other for extensive data sets from German official registration trials (1985–1989) with winter oilseed rape (Brassica napus L.), fababean (Vicia faba L.), oat (Avena sativa L.), fodder beet (Beta vulgaris L.), and sugar beet (B. vulgaris). The van der Laan‐de Kroon method is based on the crossover concept of interaction (different rank orders), while the other methods are based on the concept of deviations from additivity of main effects. The methods were compared using the numerical values of the test statistics. For the sources cultivars, locations, and interactions one obtains these relationships: ANOVA ≥ Hildebrand ≅ Kubinger > van der Laan‐de Kroon > Bredenkamp. If the assumptions for parametric methods cannot be accepted, the van der Laan‐de Kroon method is recommended for the crossover interaction concept, while the Hildebrand or Kubinger method (both of which are approximately equivalent) should be applied for the usual interaction concept. The Bredenkamp method cannot be recommended.
Inheritance of Potassium‐Sodium Nutritional Traits in Alfalfa
Authors: James David W. , Dhumal Suresh S. , Rumbaugh Melvin D. , Tindall Terry A. 
Published: July 2010

AbstractAlfalfa (Medicago sativa L.) growing on K‐depleted, semiarid, calcareous soil displays three K‐deficiency symptoms: (i) white spots on leaflets W, (ii) marginal chlorosis M, and (iii) normal leaflets on stunted plants (N). In a greenhouse study, we examined partitioning and heritability of K and Na nutritional traits in three alfalfa clones and their crosses, and also how K and Na soil fertility levels affected biomass production, genetic dependence of K and Na uptake and partitioning, and K use efficiency. Mother plants were propagated vegetatively and by seed from phenotype crosses in a low‐K, low‐Na, calcareous soil rooting medium. One trial used K‐ and Na‐amended soil. Harvests were at early bloom. Leaves contained more K than stems, with no difference among phenotypes; Na was uniform in stems, but leaves of M contained much more Na than leaves of N and W. With nonamended soil, K and Na uptake and partitioning among leaves, stems, and roots were significantly affected by cross. The Na:K ratio in leaves, stems, and roots was strongly influenced by phenotype and cross. Biomass production of leaves and stems differed among crosses and was increased by K fertilization; Na fertilization affected biomass only of leaves, and only in crosses M ✕ M and N ✕ N (Na may have partially replaced K). The shoot:root ratio was affected only by cross. Potassium use efficiency was affected by cross and by Na fertilization. Broad‐sense heritability for K and Na concentration was high, especially for Na in leaves and stems. Uptake and partitioning of Na and K in phenotype crosses supported narrow‐sense heritability as well. Genetics, rather than soil K‐Na competition, governed Na uptake, translocation, and utilization by phenotypes. Accordingly, characterization of K nutrition in alfalfa must consider Na levels. As phenotypes of alfalfa cultivars range widely in K‐Na nutritional traits, it should be possible to select for high yield and K use efficiency.
Potato Leafhopper Management: Effects on Production and Quality of Alfalfa‐Timothy Mixtures
Authors: Davis Paula M. , Fick Gary W. 
Published: July 2010

AbstractAlfalfa (Medicago sativa L.) mixtures with grasses, especially timothy (Phleum pratense L.), are widely planted in the Great Lakes Region, but most information on potato leafhopper [Empoasca fabae (Harris)] (PLH) management for new stands is based on alfalfa monocultures. Field research was conducted in 1991 and 1992 to evaluate the ability of alfalfa to recover from PLH injury following insecticide application and to compare the effect of injury on yield and quality of first‐year monocultures or mixtures. Four replicates of alfalfa monoculture and alfalfa‐timothy mixtures were established each year. One week after the first harvest in early July, eight split‐plot treatments were established in each main plot: an uncaged check, a caged check, and six combinations of two PLH infestation densities (25 or 50 PLH adults m−2) and three insecticide application dates (1 wk after infesting plots, 3 wk after infesting plots, and unsprayed). Crop mixture had no effect on PLH nymphal populations on a per stem basis. Although differences between years were noted, delaying insecticide application generally reduced forage yield and quality, delayed crop maturity, and increased weed content, particularly in forage mixtures. There was little evidence that seedling timothy could compensate for PLH injury to alfalfa. Data on stem elongation and dry matter accumulation indicated that alfalfa can recover from leafhopper injury; however, dry matter production did not increase for at least 2 to 3 wk following a spray application. Reductions in forage crude protein due to PLH injury were a result of both reduced crude protein content in the alfalfa and an increase in the proportion of weed biomass in the forage. Early detection and rapid response to economically significant populations are necessary to realize the greatest benefit from treatment. The presence of timothy in the mixture does not alter PLH management recommendations for new stands.
Evaluation of Video Image Analysis and Line‐Intercept Methods for Measuring Root Systems of Alfalfa and Ryegrass
Authors: Murphy Stephanie L. , Smucker A. J. M. 
Published: July 2010

AbstractImproved quantification of plant root systems is essential for determining the functional efficiencies of plant roots. The objective of this study was to evaluate the video image analysis procedure of quantifying roots of different species and compare it with more traditional measurements. Three methods were used to quantify roots of alfalfa (Medicago sativa L.) and perennial ryegrass (Lolium perenne L.) from a greenhouse experiment: (i) root length by video image analysis, (ii) root length by the line‐intercept method, and (iii) dry root weight. Estimates of root length by image analysis and line‐intercept methods were comparable for alfalfa and were positively correlated with root weight. In contrast, the correlation between image analysis and line‐intercept estimates of ryegrass root length was poor (r2 = 0.090), and no significant relationship was found between ryegrass root length and root weight. Difficulty in the quantification of ryegrass roots was related to the large numbers of very fine roots, which resulted in extremely large root lengths and excessive error. Root data of ryegrass (and species with similar root morphology) obtained by the line‐intercept method may provide only relative values to be compared among these species. The image analysis method of root measurement is bound to improve root data with increased magnification and resolution of the video images when the root density in the image (cm cm−2) is sufficiently low.
Laboratory Freeze Tolerance of Field‐Grown Forage Bermudagrass Cultivars
Authors: Anderson Jeffrey A. , Taliaferro Charles M. 
Published: July 2010

AbstractFreeze tolerance is a limiting factor in production of many bermudagrasses (Cynodon spp.) in the transition zone between warm‐ and cool‐season grasses. Our objective was to evaluate the seasonal patterns of freeze tolerance in five forage bermudagrass cultivars. Midland, Hardie, Tifton 44, World Feeder, and Gordon's Gift were grown in field plots and acclimated under natural conditions, then subjected to laboratory freeze tolerance evaluations. Lowest survival temperatures (LSTs) were determined at monthly intervals from November through May in 1992‐1993 and 1993‐1994. LSTs were between −5 and −7°C for all cultivars in early November. Gordon's Gift had the greatest freeze tolerance in midwinter, surviving exposure to ≈ −11°C in 1992‐93 and ≈ −10°C in 1993‐94. Gordon's Gift was significantly more freeze tolerant than the other cultivars on most dates. The differences in freeze tolerance among the cultivars tested indicates substantial variation in the species that may be used for breeding improvement.
CPM: Software for Cotton Final Plant Mapping
Authors: Plant Richard E. , Kerby Thomas A. 
Published: July 2010

AbstractFinal plant mapping in cotton (Gossypium hirsutum L.) is the practice of recording from a sample of plants the location of every retained boll on the plant, together with ancillary whole‐plant information. We have developed an easy‐to‐use computer program called CPM (Cotton Plant Mapper) for efficient entry and statistical analysis of final plant map data. It takes plant‐by‐plant data as input and generates statistical information on the sample. It also permits samples to be merged into an aggregate so that summary statistics may be computed. The program is intended primarily for use on a palmtop computer, permitting direct data entry. It features a sequential sampling procedure that indicates when a sufficiently precise estimate of whole‐plant data has been obtained and sampling may be stopped.
Yield and Botanical Composition of Legume‐Interseeded vs. Nitrogen‐fertilized Switchgrass
Authors: George J. Ronald , Blanchet Kevin M. , Gettle Randall M. , Buxton Dwayne R. , Moore Kenneth J. 
Published: July 2010

AbstractSwitchgrass (Panicum virgatum L.) has a relatively high N requirement for high yields of quality forage. It is not clear what role legumes can play in supplying this N and in improving herbage yield when grown in association with switchgrass. To evaluate cool‐season legume renovation vs. N fertilization of established switchgrass, 10 forage legumes and a legume mixture were compared with 0, 60, 120, and 240 kg N ha−1. Forage yield and botanical composition of basal (<20 cm) and upper (>20 cm) canopy were compared at Ames, IA, on a Webster silty clay loam (mesic Typic Haplaquoll). Legumes were no‐till interseeded in early April; N was applied before mid‐May. Legume renovation did not affect June yield during the establishment year (Yl), but produced 9% greater yields than 0‐N grass in July. N fertilization increased uppercanopy grass yield 2.4‐fold compared with 0 N and legume renovation during Yl. During the second year (Y2) of 1991 seedings, all legume treatments except crownvetch (Coronilla varia L.) produced more totalseason upper‐canopy yield than grass fertilized with 240 kg N. For 1992 seedings, birdsfoot trefoil (Lotus corniculatus L.), Mammoth red clover (Trifolium pratense L.), and trefoil‐red clover mixture had Y2 yields that equaled or exceeded yield for 240 kg N. Mean legume composition of Y2 upper canopy for June, July, and August was 84, 70, and 51%, respectively, in 1991 seedings and 53, 28, and 27% in weather‐damaged stands of 1992 seedings. Y2 yields for interseeded legumes provided significant improvement over 120 or 240 kg ha−1 N, so cool‐season legumes can substitute for N fertilization after the seeding year. Adequate defoliation in early June is important to minimize legume competition to established switchgrass. Livestock producers should renovate only a portion of switchgrass pastures in a single year, because of a shortfall in forage supply during legume establishment compared with that of N‐fertilized grass.
Foliar Methanol Applications to Cotton in the Southeastern United States: Leaf Physiology, Growth, and Yield Components
Authors: van Iersel Marc W. , Heitholt James J. , Wells Randy , Oosterhuis Derrick M. 
Published: July 2010

AbstractFoliar methanol applications have previously been reported to dramatically increase yields of a variety of crops under arid conditions, including cotton (Gossypium hirsutum L.). Whether methanol is effective in the southeastern USA is not known. In addition, the agronomic and physiological events contributing to the increase are not understood. Therefore, we conducted a series of experiments in 1993 to study the effects of methanol on the gas exchange, water relations, development, growth, and yield of field‐grown cotton at three locations in the southeastern USA. Conventional management and irrigation procedures were used. Methanol solutions in water, with and without urea and iron, were applied over the top at midday to cotton. Four to eight applications were made from flowering to late boll filling. Both single‐leaf and canopy photosynthesis rates taken 2 h to 6 d after treatment were unaffected by methanol or the nutrients. At one site, CO2 compensation point was determined, but did not differ among treatments. This finding does not support previous claims that methanol reduces photorespiration. Transpiration and water potential also were not affected by foliar applications of 15 or 30% methanol (v/v). Foliar methanol applications also did not result in faster development of the crop and did not increase yield at any of the locations. Our results do not indicate any positive effect of foliar methanol applications on cotton in the southeastern USA.
Performance of Buffelgrass Germplasm with Improved Winter Survival
Authors: Hussey Mark A. , Bashaw Elexis C. 
Published: July 2010

AbstractLack of winter hardiness in buffelgrass [Cenchrus ciliaris L.; syn. Pennisetum ciliare (L.) Link] currently limits the utilization of this species in Texas and northern Mexico. This study was conducted to assess differences in field survival and yield potential of buffelgrass germplasm believed to have increased levels of winter hardiness. To document differences in field winter survival seedlings of five buffelgrass genotypes (‘Common’, ‘Llano’, ‘Nueces’, PI 409704, and T‐7040) were established at six locations in Texas ranging from 28 to 34°N latitude. The winter‐hardy species Pennisetum orientale L. cv. Cowboy was included as a check. The buffelgrass entries PI 409704 and T‐7040 (a 2n + n hybrid between 409704 and an unknown male parent) had greater field survival than the cultivars Common, Llano, and Nueces, but were less winter hardy than Cowboy at the three locations (Knox City, Stephenville, and Vernon) north of College Station. All entries survived the winter at Beeville, College Station, and Uvalde. Yield at two cutting heights was evaluated over a 3‐yr period at College Station. The rhizomatous cultivars Llano and Nueces had the greatest yield when harvested at 50 mm, while no significant differences existed among Llano, Nueces, PI 409704, and T‐7040 when harvested at 150 mm. Defoliation height influenced winter survival of Common buffelgrass at College Station. During the winter of 1987–1988, 60 and 20% of the Common plants failed to survive at the 50‐ and 150‐mm defoliation heights, respectively. Defoliation height did not affect crown nonstructural carbohydrate concentration (CHO). The most winter‐hardy entry, Cowboy, had the highest CHO; the least winter‐hardy entry, Common, had the lowest. These results suggest that winter‐hardy pentaploid buffelgrass germplasm such as PI 409704 have the potential to expand the current range of buffelgrass.
Plant Analysis with Standardized Scores Combines DRIS and Sufficiency Range Approaches for Corn
Authors: Baldock Jon O. , Schulte Emmett E. 
Published: July 2010

AbstractThe Sufficiency Range (SR) system and the Diagnosis and Recommendation Integrated System (DRIS) represent two competing approaches to interpreting plant analyses. Our objectives were (i) to show that the two approaches are complementary and (ii) to introduce a new plant analysis system that combines them, called Plant Analysis with Standardized Scores (PASS). The SR provides discrete, easily computed independent nutrient indices (INI). The DRIS determines continuous, difficult to calculate, but easily interpreted dependent nutrient indices (DNI), plus an overall balance index and a ranking of the relative deficiencies. Those differences are complementary; that is, the strengths of the one are the weaknesses of the other, and vice versa. The PASS system combines the strengths of the SR and DRIS by including an INI section and a DNI section, in which both types of indices are on the convenient DRIS scale. When we compared the ability to diagnose deficiencies and sufficiencies in 24 corn (Zea mays L.) dry matter or grain yield comparisons, PASS had a higher efficiency rating (82%) than the SR (41%) and DRIS (33%). The PASS system had a significantly higher proportion of correct diagnoses of deficient nutrients than the DRIS and a significantly greater proportion of correct diagnoses of sufficient nutrients than the SR. Furthermore, the PASS overall index, but not the DRIS, was significantly correlated with relative corn grain yield in 10 comparisons showing a yield response.
Spatiotemporal Variability of Corn and Soybean Yield
Authors: Jaynes Dan B. , Colvin Thomas S. 
Published: July 2010

AbstractLittle is known about the spatial structure of yield across fields, nor of the temporal stability of this structure. We determined the spatial structures of grain yield for 6 yr of data and examined the stability of these structures over time. Yields were measured each year at 224 locations on an 8 × 24 grid within a 16‐ha field, using plot combines. The field was planted either to corn (Zea mays L.) or soybean [Glycine max (L.) Merr.] in an alternate‐year rotation. Soybean yields averaged 3.16, 3.14, and 3.12 Mg ha−1 in 1990, 1992, and 1994. Corn yields averaged 9.30, 9.34, and 5.02 Mg ha−1 in 1989, 1991, and 1993 with the lower yield in 1993 a result of excessive rainfall that year. The large‐scale deterministic structure of the spatial yield data was constructed for each year by median polishing. The trend surfaces were different for each year, indicating a lack of temporal stability in large‐scale structure, although the trend surfaces shared some similar features. Overall, the deterministic structure accounted for about 25% of the overall yield variance. The small‐scale stochastic spatial structure was determined by computing variograms of the yield residuals after subtracting the trends. Variograms showed strong spatial structure of the yield residuals, with zero nugget and correlation ranges approaching 150 m. Variograms differed from year to year and were not related to the crop being grown. The range was significantly correlated to precipitation, increasing with increasing total growing‐season rainfall. Long‐term monitoring of yield will be necessary to fully characterize its spatial‐temporal pattern.