bluuebunny/crossref_metadata_2025_split huggingface dataset:
Increase in Drought Resistance of Cotton Seedlings Treated with Mepiquat Chloride
Authors: Xu X. , Taylor H. M. 
Published: July 2010

AbstractUnder rainfed conditions, plant establishment is often low in cotton (Gossypium hirsutum L.) because of water limitations. Increasing drought resistance of cotton seedlings by accelerating root growth thus has important, practical implications. Much research has been devoted to modifying plant root systems for more effective use of soil water, but successful results are few. We studied the effects of mepiquat chloride (MC; 1,1‐dimethylpiperidinium chloride) on drought resistance of cotton seedlings. Well‐watered seedlings were irrigated with mepiquat chloride (0‐40 mg kg−1), and then subjected to progressively greater water stress. Treatment with MC accelerated root growth and increased water absorption, especially at greater soil depths. The seedlings treated with MC were turgid longer and wilted less than the drought controls. In another series of experiments seeds were treated (0‐4000 mg kg−1) and arising plants were assessed for growth and survival in both well‐watered and water‐stress conditions. A seed treatment of 500 mg kg−1 gave shorter and more compact shoots, did not affect leaf area, but increased specific leaf weight and chlorophyll content. Seed treatment with 500 mg kg−1 MC also gave the greatest enhancement of root growth, water extraction from deep soil layers, and survival of stressed seedlings. These results suggested a potential for using MC to modify root patterns and increase drought resistance of cotton seedlings. Field tests of seed treatments with MC should be conducted to determine whether seedling survival is enhanced under natural drought‐stressed conditions. The responses of different cotton varieties to MC treatment also should be investigated.
Cellulase Solution Concentrations Used to Develop Spectral Equations for Predicting Tall Fescue Digestibility
Authors: Bughrara S. S. , Sleper D. A. , Roberts C. A. 
Published: July 2010

AbstractDigestibility estimates obtained with prepared cellulase solutions and near infrared spectrophotometry (NIRS) have become valuable and reliable tools for forage quality determination. The objective of this study was to determine the optimum concentration of a prepared cellulase solution from a commercial source to obtain meaningful estimates of in vitro dry matter digestibility (IVDMD) and development of NIRS equations for tall fescue (Festuca arundinacea Schreb.). A total of 176 tall fescue samples were pretreated using pepsin and 0.125 M L−1 HCI followed by digestion using five different concentrations of a prepared cellulase solution obtained from Worthington Corp., Freehold, NJ. Concentrations of the prepared cellulase solution were 0.0, 0.2, 0.4, 0.6, and 0.8 g L−1. Maximum digestion occurred with the prepared cellulase solution at 0.57 g L−1. However, the most meaningful equation for estimating tall fescue IVDMD by NIRS occurred when samples were digested using the prepared cellulase solution at a concentration of 0.8 g L−1.
Corn Motion in the Wind During Senescence: I. Motion Characteristics
Authors: Flesch T. K. , Grant R. H. 
Published: July 2010

AbstractLodging in corn (Zea mays L.) is often the result of wind‐induced motion, which creates a strain on the stalk and root system. A study was conducted to characterize corn motion during windy periods at senescence and examine the implications for lodging. Motion was measured on 23 plants with a modified computer joystick during 6 d in October, 1988, at West Lafayette, IN. The wind force on each plant was estimated from within‐canopy wind speeds, foliage area distribution, and foliage drag coefficients. Results showed that corn stalk displacement during windy periods was variable over time. The displacement pattern was distinct from the wind force pattern, and characterized by a resonant oscillation at a frequency near 1 Hz. Generally there was greater displacement in the across‐row direction than in the along‐row direction, with the across‐row displacement variance more than four times larger than the along‐row variance. There was little effect of wind direction on motion characteristics. In addition, there was a decrease in maximum displacements and the amplitude of resonant oscillation when the ear fell from an upright position to a hanging position. The nature of the corn motion suggests that dynamic plant motion characteristics may be important in determining lodging resistance.
Alfalfa Yield Component Responses to Seeding Rate Several Years after Establishment
Authors: Kephart Kevin D. , Twidwell E. K. , Bortnem R. , Boe A. 
Published: July 2010

AbstractLittle information is available regarding the relationships of alfalfa (Medicago sativa L.) forage yield with yield components in seed‐established stands grown under dryland conditions. Field experiments that included two cultivars and 15 seeding rates ranging from m 2.2 to 33.6 kg pure live seed ha−1 were established in 1985 at Brookings and Highmore, SD. The objective was to determine seeding rate effects on components of alfalfa forage yield and on plant morphology several years after establishment. In the seeding year, plant density increased linearly with seeding rate at both locations. Yield components were determined in 1988 and 1989. Mean alfalfa yield during 1988 and 1989 was optimum at the 13.4 kg pure live seed ha−1 rate at Brookings, but did not respond to seeding rate at Highmore. Plant density continued to be affected by seeding rate 4 yr after establishment, but greater mortality at high seeding rates caused the response to deviate from linearity. Shoots per plant were negatively correlated with plant density (r = –0.73, P = 0.01). Shoot weight did not respond to seeding rate at Brookings but declined linearly with seeding rate at Highmore. Nevertheless, path analysis suggested that shoot weight was the major influence on alfalfa yield at both locations. Leaf‐to‐stem ratio and shoot length were not affected by seeding rate. Alfalfa yield components are affected similarly by plant density in seed‐established and transplanted stands. Although yield may not be affected by plant density, shoot weight may be affected because of differences in plant competition.
Big Bluestem and Switchgrass Establishment as Influenced by Seed Priming
Authors: Beckman Jana J. , Moser Lowell E. , Kubik Keith , Waller Steven S. 
Published: July 2010

AbstractSeed dormancy and slow seedling development often limit establishment of warm‐season grass stands. Establishment of seedlings with two solid matrix seed priming (SMP) treatments [2‐d moistened (17°C) and 14‐d wet‐chill (4°C)] was compared with untreated seed of ‘Kaw’ and ‘Pawnee’ big bluestem (Andropogon gerardii Vitman) and ‘Path‐finder’ and ‘Cave‐in‐Rock’ switchgrass (Panicum virgatum L.) in greehouse and field experiments. In two greenhouse studies, seedling emergence was monitored from 7 to 26 d after planting and number of adventitious roots were monitored from 2 to 5 wk after planting. Field experiments were initiated on 19 Apr. 1988, 3 June 1988, and 23 May 1989, on a Sharpsburg silty clay loam (fine montmorillonitic, mesic, Typic Argiudolls). In the greenhouse, SMP treatments increased big bluestem emergency by 18%. In the field, final seedling emergency from dry untreated big bluestem seed was equal to or higher than that of SMP‐treated seed. The SMP treatments had no effect on adventitious root formation for big bluestem in either greenhouse or field experiments. In the greenhouse, the moistened and wetchill treatments increased seedling emergency of switchgrass 35 and 150%, respectively. In the greenhouse, SMP treatments slightly increased the percentage of switchgrass plants with adventitious root development 5 wk after planting but not in the field studies. Number of adventitious roots per plant were unaffected by treatment. In the field, the SMP‐treated seed produced the highest seedling emergence for switchgrass under moist planting conditions and had the potential to improve stands when seed was planted without drying. However, final seedling emergence from dry untreated seed was greater than that for SMP‐treated seed under dry soil conditions.
Soybean Yield Interaction between Helicoverpa zea Infestation and Simulated Frost Injury
Authors: Eckel Craig S. , Bradley J. R. , Van Duyn John W. 
Published: July 2010

AbstractSoybean, Glycine max (L.) Merr., yields may be reduced by corn earworm, Helicoverpa zea (Boddie), feeding and by early frosts. One consequence of H. zea feeding can be a delay in pod development. A consequence of frost injury can be shortening of the seed fill duration. The objective of 12 experiments conducted at multiple locations from 1984 to 1987 was to evaluate the potential for an interaction between H. zea feeding damage and early frost. Insecticides were used to establish varying levels of H. zea populations in soybean and paraquat (1,1′.dimethyl‐4,4′‐bipyridinium dichloride) was used to simulate frost injury. Significant yield differences between levels of H. zea populations were detected in eight experiments, and paraquat treatments significantly reduced yields in 11 experiments. A significant interaction between H. zea population level and paraquat treatment time occurred in three experiments. In these experiments, yield reduction due to paraquat was greater where H. zea populations were larger. Although soybean can compensate for a delay in pod set caused by H. zea feeding in most years, when seed fill period is shortened, as would occur with early frost, a delay in pod set can contribute to yield loss. Identifying one of the many factors that lead to variation in yield loss from a particular level of H. zea infestation, is a step towards more effective management of this pest.
Differences in Response to Available Phosphorus among White Clover Cultivars
Authors: Gourley C. J. P. , Allan D. L. , Russelle M. P. 
Published: July 2010

AbstractThe selection of agriculturally important plant germplasms more tolerant of low P may increase productivity on P deficient soils and reduce P fertilizer requirements. Differences in response to P availability among six cultivars of white clover (Trifolium repens L.) were investigated in a series of pot experiments using a sand‐alumina culture technique and two low P soils, an acid Hapludult with 2.6 mg Bray‐P kg−1 and a calcareous Calciaquoll with 6.9 mg NaHCO3‐extractable P kg−1. Plants were grown in the greenhouse or growth chamber for up to 63 d in solution [P] of 0 to 82 μM. Plant characteristics measured included dry mass and P concentration of shoots, coarse roots, and fine roots; P distribution within the plant; and root traits of total length, root hair length and number per unit root surface area, and root tip number. There were significant differences in shoot dry mass and P accumulation response curves among cultivars; cultivar rankings were consistent in sand‐alumina and in soils, but differed from other reports in the literature. We found significant cultivarby‐solution [P] interactions when only low vs. high P availabilities were compared, but not when response curves were generated and compared. Differences in herbage yield and P accumulation were associated with larger root systems, but there was no evidence of greater efficiency of P uptake or utilization in these cultivars.
Potential Economic Benefits of Modifications to Urea That Increase Yield through Reduction in Nitrogen Losses
Authors: Buresh R. J. , Baanante C. A. 
Published: July 2010

AbstractMany modifications to urea such as inhibitors, algicides, soluble salts, and acidifying agents have been proposed to overcome losses of urea‐N, but little is known about the potential economic benefits and acceptable farm‐level prices for modified urea. The objective of this study was to develop and use a method for estimating the potential economic benefits of modifications to urea that reduce N losses and enhance crop yields. The method is applicable for crops with a response to N that is well represented by a quadratic model, and for modifications to urea that do not alter the maximum attainable yield with added N. The increment in profit of farmers with the use of modified urea is determined by the difference in net benefit between modified urea and conventional urea when these fertilizers are used at rates that maximize profit. The increment in profit with modified urea increased linearly with increasing saving of N from loss, decreased with the increasing cost of modifying urea, and increased as the price of conventional urea‐N increased. The increased price of N for modified urea, expressed as a percentage increase over the price of conventional urea‐N, must be <20% when N saving = 17% of applied N, <40% when N saving = 29% of applied N, and <80% when N saving = 44% of applied N to obtain a positive increment in profit. The results suggest that modified urea would be most economical in environments with high response of the crop to urea‐N, high price of conventional urea, and high losses of urea‐N that can be prevented by the urea modification.
Monte Carlo Distributions of Parameters Relating to a Superiority Measure for Cultivar Assessment
Authors: Binns M. R. , Lin C. S. 
Published: July 2010

AbstractA cultivar × location trial is the standard method for providing data by which new cultivars are assessed. To measure a test cultivar's general adaptability in such a trial, a superiority measure (designated as its Pi value) has been defined as the distance mean square between the test cultivar and the maximum yield at that particular location. A cultivar is considered to be better adapted if its Pi value is small. However, the distribution of differences from the maximum yield at each location in the context of cultivar × location data is unknown. This creates difficulties in measuring the difference between the cultivar mean and the mean of the maximum, and testing the pairwise interaction sum of squares between the maximum and the test cultivar. A computer program for Monte Carlo simulation can obtain approximations to the distribution of differences between the maximum location mean and a cultivar mean. This is then used to obtain probability intervals for comparing cultivar means with the location maximum. Approximate distributions are obtained for the Pi value and the pairwise genotype × environment interaction between the cultivar and the location maxima.
Effect of Nitrogen and Harvest Grain Moisture on Head Rice Yield
Authors: Jongkaewwattana Sakda , Geng Shu , Brandon Marlin D. , Hill James E. 
Published: July 2010

AbstractIn rice (Oryza sativa L.) production, both grain yield and milling quality play an important role in determining the grower's income. Nitrogen input is essential in maintaining a desirable yield, but its effect on rice milling quality is less clear. This study examined optimal N input for rice milling quality and the combined effect of N and grain moisture at harvest on both grain yield and head rice yield. Experiments were conducted in California at the Rice Experiment Station, Butte County, on three cultivars (S201, M201, and L202) during the 1987 and 1988 growing seasons to determine the effects and optimum levels of N and grain moisture at harvest on milling quality. Results showed that the optimal harvest grain moisture to produce the maximum head rice yield depended on the levels of N applied and ranged between 220 and 270 g kg−1 for S201, 210 to 270 g kg−1 for M201, and 200 to 250 g kg−1 for L202. The optimal N level for maximum head rice yield was 125 kg ha−1 for S201, 112 kg ha−1 for M201, and 130 kg ha−1 for L202. These optimum N rates fell within the lower half region of the required N for 0.95 confidence of producing the maximum grain yield. Thus, optimum N inputs for head rice yields are also likely to produce maximum grain yields for the cultivars studied. These findings will greatly simplify the management requirement on N application for California rice farming.
Photoperiod‐Induced Dormancy in Cicer Milkvetch
Authors: Townsend C. E. 
Published: July 2010

AbstractCicer milkvetch (Astragalus cicer L.) does not produce as much forage as alfalfa (Medicago sativa L.) under field conditions during the third growth period, which ranges from about 1 August to 15 September in Colorado. This study examined the effect of decreasing photoperiod on the herbage growth of cicer milkvetch. Spaced plants of the component polycross progenies of the cultivar Monarch were grown in the field under irrigation on a Nunn clay loam soil (fine, montmorillonitic, mesic Aridic Argiustoll). These progenies were subjected to one of four clipping treatments, removing the top growth on 18 July, 25 July, 1 August, or 8 August. Substantial variability was detected among plants within each clipping treatment date for extended height, which suggests that photoperiod was the primary factor controlling plant growth. Therefore, growth chamber studies were designed that exposed polycross progenies of selected germ plasm and Monarch to a constant 15‐h photoperiod and a gradually decreasing photoperiod equivalent to the natural daylength at Fort Collins, CO, from 1 August through 15 September. Plants under the decreasing photoperiod treatment were 23% shorter and produced 25% less shoot dry matter than those under the constant photoperiod. Under the decreasing photoperiod there were also fewer flowering plants and fewer racemes per plant than under the 15‐h photoperiod. Considerable variability for extended height and shoot dry weight was detected among plants under both photoperiods. These studies demonstrated the presence of a photoperiod‐induced dormancy trait in cicer milkvetch.
Modeling Tall Fescue Cultivar Response to Applied Nitrogen
Authors: Overman Allen R. , Wilkinson Stanley R. 
Published: July 2010

AbstractModels can be used to estimate yields and nutrient utilization by forage grasses. The objective of this study was to model response of three cultivars of tall fescue (Festuca arundinacea Schreb.) to applied N over a 3‐yr period at Watkinsville, GA. The procedure uses analysis of variance to evaluate linear parameter A and the exponential parameters b and c for the logistic equation. It was shown that yields could be averaged across years and that all differences among cultivars could be assigned to the b (intercept) parameter. ‘All‐Triumph’ proved to be more efficient at converting soil N to dry matter without applied N than either ‘Johnstone’ or ‘Kentucky 31’ cultivars. Endophyte (Acremonium coenophialum Morgan‐Jones & Gams) infection did not affect dry matter response relationships of Kentucky 31. Maximum incremental conversion of applied N to dry matter occurred at N = 125 kg ha−1, where plant N utilization was ≈80%. The logistic model provides a very useful tool for evaluating response of tall fescue cultivars to applied N.
Boll Weight and Within‐Plant Yield Distribution in Field‐Grown Cotton Given Different Levels of Nitrogen
Authors: Boquet Donald J. , Moser Edgar Barry , Breitenbeck Gary A. 
Published: July 2010

AbstractIncreased understanding of N effects on fruiting and yield of cotton (Gossypium hirsutum L.) could lead to more efficient use of N fertilizer and increased yields. We determined the influence of N rate on boll size and yield distribution of cotton plants by measuring individual boll weights (IBW) and average seedcotton yield at each potential fruiting site (FS). Field experiments were conducted from 1987 through 1990 on Commerce silt loam (fine‐silty, mixed, nonacid, thermic Aeric Fluvaquent) to assess the response of cotton to preplant N rates of 0, 28, 56, 84, 112, 140, and 168 kg ha−1 and to a split application of 56 + 56 kg N ha−1. Increasing N rate from 0 to 84 kg ha−1 increased average whole‐plant IBW by 0.16 g and average yield per fruiting site by 0.29 g. Response of IBW and FS yield to N rate was dependent on the location of FS on the plant. Individual boll weight was maximized in Horizon 1 (mainstem nodes 5 through 10) with 28 kg N h−1, in Horizon 2 (mainstem nodes 11 through 16) with 56 kg N h−1, and in Horizon 3 (mainstem nodes 17 through 24) with 140 kg N h−1. Yield at fruiting site 1 (FS1) in Horizon 1 decreased from 2.3 to 1.7 g as N rate increased from 0 to 168 kg ha−1. Nitrogen fertilization of 84 kg ha−1 increased FS1 yield in Horizon 2 from 2.3 to 3.1 g, and increased FS1 yield in Horizon 3 from 0.27 to 1.1 g. Increasing N rate redistributed plant yield by decreasing the yield contribution of Horizon 1 from 43 to 28%, increasing the yield contribution of Horizon 2 from 44 to 48% and increasing the yield contribution of Horizon 3 from 7 to 22% of the total plant yield. The contribution of monopodial branches was <6% of total yield for all treatments and was decreased by application of >56 kg N ha−1. The application of optimal N rates benefited cotton yield by producing larger bolls at a greater number of fruiting sites. Increase in yield by increase in IBW and FS weight was limited, because gains in Horizon 3 were offset by negative responses in Horizon 1 when the N rate exceeded 84 kg ha−1
Simulation by NCSWAP of Seasonal Nitrogen Dynamics in Corn: II. Corn Growth and Yield
Authors: Lengnick Laura L. , Fox Richard H. 
Published: July 2010

AbstractThe accurate simulation of crop growth is important in the effort to apply computer simulation models to improvements in the management of N resources in agricultural systems. The objective of this study was to validate the crop growth submodel of the model NCSWAP using seasonal corn (Zea mays L.) growth and final grain yields from a 3‐yr N rate‐study conducted in central Pennsylvania. The results of the validation suggest that the model poorly simulated crop growth response under conditions of limited water or N availability. However, NCSWAP accurately simulated observed seasonal corn growth and harvested yields in treatments with no N or water limitations. The crop growth submodel has the potential to be useful in simulation of crop production, because with a minimum of inputs it can be calibrated for any crop and can incorporate variables that influence crop growth and are specific to a local environment. Improvements in the simulation of crop growth under N and water deficits would enhance the usefulness of NCSWAP to researchers exploring seasonal N cycling in soils and crops.
Estimating Leaf Mass from Light Interception Measurements on Isolated Plants of Erythroxylum Species
Authors: Acock M. C. , Daughtry C. S. T. , Beinhart G. , Hirschmann E. , Acock B. 
Published: July 2010

AbstractTo determine the extent of coca (Erythroxylum spp.) production in the world, some method for estimating yield (leaf mass) in a variety of habitats is required. A computer model that simulates the growth of coca plants has the versatility for making these estimates, but there must be some reliable method to validate the model. The objective of this research was to validate the use of measurements of light interception and specific leaf area (SLA, m2 kg−1) for estimating yield. Leaf area was calculated from light interception measurements made on plants grown as hedgerow or as isolated plants, then converted to leaf mass using measurements of SLA. Light interception was measured with the Decagon Sunfleck Ceptometer (SC) and the LI‐COR Plant Canopy Analyzer (PCA). Leaf disks of known area from Erythroxylum coca var. coca and Erythroxylum novogranatense var. novogranatense were cut, dried, and weighed to determine SLA values. Leaf fresh weights were measured and corrected to dry weight using the fresh to dry weight ratio obtained from a sample at harvest. Estimated leaf mass regressed on observed leaf mass demonstrated that PCA was superior to SC in estimating leaf mass on isolated plants of various sizes using the techniques described in this paper. Leaf area was consistently underestimated by the SC. The estimates of leaf mass from the PCA gave the lower mean, absolute mean, and root mean square error terms compared with SC, and the slope of the regression line of observed leaf mass vs. predicted leaf mass was closest to a value of 1.0.