bluuebunny/crossref_metadata_2025_split huggingface dataset:
Yield and Quality of Semidwarf and Standard‐Height Sunflower Hybrids Grown at Five Plant Populations1
Authors: Majid Hashim R. , Schneiter A. A. 
Published: July 2010

AbstractInformation on yield and agronomic performance of semidwarf sunflower (Helianthus annuus L.) is limited. The objectives of these field studies were: (i) to acquire information on seed yield and other agronomic characteristics of two semidwarf and two standard‐height sunflower hybrids; and (ii) to determine an optimum plant population for hybrids representing both plant types. Two experimental semidwarf (SD) and two standard‐height (SH) hybrids of similar maturity from Cargill and Sigco research breeding programs were grown at populations of 32 123,49 420,66 717,84 014, and 101 311 plants/ ha over a 3‐yr period (1982‐1984) under dryland conditions at Fargo, Carrington, and Prosper, ND. Yield differences were observed dependent on the hybrid but not on plant type. The Cargill SD and Cargill SH genotypes had similar but higher yields than both 894 SH, a commonly grown hybrid, and Sigco SD, which were not significantly different from each other. Yield differences among hybrids were the consequence of differences in seed weight and seed per head. Cargill SH had the highest oil percentage and test weight. It was concluded that the semidwarf hybrids did not possess any yield superiority when compared to the two standard‐height sunflower hybrids. A plant population of 32 123 plants/ha resulted in the highest yield for hybrids representing both plant types. Plant populations above 32 123 plants/ha decreased yield, seed weight, seed per head, and head diameter, but increased percent oil.
Effects of Nitrogen and Potassium on Growth and Cation Composition of Corn Genotypes Differing in Average Ear Number1
Authors: Ebelhar S. A. , Kamprath E. J. , Moll R. H. 
Published: July 2010

AbstractGenetic improvements for increased grain yield through selection for prolificacy in corn (Zea mays L.) may affect plant responses to fertilizers. A field study was conducted on a Dothan loamy sand (Typic Plinthic Paleudult) to determine the effects of N and K rates on growth, grain yield, and concentrations of N, K, Ca, and Mg in the leaves of corn genotypes differing in average ear production. Nitrogen rates of 50, 150, and 250 kg N ha−1 and K rates of 0, 50, and 100 kg K ha−1 were used in factorial combination with prolific (Pr), semi‐prolific (SP), and nonprolific (NP) genotypes at plant densities of 34 000 and 68 000 plants ha−1. Leaf weight and grain yield of all three genotypes were increased with N fertilization. Response above 150 kg N ha−1 was relatively small. Yield response to K was obtained at 150 kg N ha~' but not at 250 kg N ha−1 in a year with optimum conditions for yield. Lack of K response at the high N rate was a result of greater uptake of soil K. Nitrogen rate had a greater effect on K uptake than K rate. Leaf concentrations of Ca, Mg, and K increased with N rates and were greatest with the Pr and SP genotypes. The Pr and SP genotypes had considerably higher leaf concentrations of Ca and Mg and total cation concentration than the NP genotype. However, the NP genotype had the highest leaf N concentration. Increasing K rates decreased Ca and Mg concentrations in the leaves but had little effect on total cation concentration.
Intercropping Soybean into Standing Green Wheat1
Authors: Reinbott T. M. , Helsel Z. R. , Helsel D. G. , Gebhardt M. R. , Minor H. C. 
Published: July 2010

AbstractScientists and farmers have been evaluating the intercropping of soybean [Glycine max (L.) Merr.] into wheat (Triticum aestivum L.) before harvest as an alternative to doublecropping in the lower Midwest. It was our objective to examine the interrelationships of soybean row spacing, planting date, and N applied to wheat in a wheatsoybean intercropping system. The experiment was conducted near Columbia, MO, in 1983, 1984, and 1985, on a Mexico silt loam (Udollic and Mollic Ochraqualf). Whole‐plot treatments consisted of two cropping systems (conventional and intercropped), drilled and skiprow planting patterns (0.2‐ and 0.8‐m row spacings of soybean), and three soybean planting dates coinciding with wheat growth stages. Subplots consisted of spring applied N treatments (0, 56, and 112 kg ha−1). A wheat‐soybean double crop was also included. Wheat yields were reduced 23 and 16% when soybean was intercropped in the drilled and skiprow patterns, respectively. The date of planting did not significantly (P < 0.05) influence wheat yield in the skiprow patterns. However, wheat yield was significantly (P < 0.05) decreased as planting date was delayed in the drilled pattern because of mechanical damage. Intercropped soybean yielded 27% less than conventional soybean but 28% more than doublecropped soybean over all years and treatments. Drilling soybean at the heading stage of wheat resulted in greatest yields. In 1985, N applied in excess of 56 kg ha−1 produced excessive wheat vegetative growth resulting in competition for light which caused a reduction in drilled, intercropped soybean yield. Where mechanical damage to wheat can be minimized, drilling soybean in wheat at heading can result in optimum intercrop performance.
Effect of Temperature, Moisture, and Soil Texture on DCPA Degradation
Authors: Choi J. S. , Fermanian T. W. , Wehner D. J. , Spomer L. A. 
Published: July 2010

AbstractTurf managers sometimes experience poor or early loss of control of targeted weeds, even when herbicides are applied at recommended rates. This study was conducted to determine the influence of soil temperature and moisture on the rate of DCPA (dimethyl tetrachloroterephthalate) degradation in soil. The effect of six soil temperatures, three soil moistures, and three soil textures on the degradation of DCPA was measured in the laboratory through HPLC analysis. Soil temperature influenced the rate of DCPA degradation in the following order: 10<<15<<20<25=30>35°C. The average half‐life ranged from 92 d at 10°C to 18 d at 30°C. Soil moisture content influenced the rate of degradation in the following order: low (0.1 kg H2O kg−1 soil)≤ medium (0.2 kg H2O kg−1 soil) = high (0.4 kg H2O kg−1 soil). The average half‐life values of DCPA were 49, 33, and 31 d for the low, medium, and high soil moisture levels, respectively. A mathematical model of DCPA loss was utilized to determine the relative contribution of time, soil moisture, and soil temperature to the rate of degradation. Faster degradation of DCPA was observed from a sand/soil moisture (47.5:52.5, w/w) than from either a sand or a soil (Flanagan silt loam [fine, montmorillonitic, mesic Aquic Argiudoll]). It was concluded that the dissipation rate of DCPA is largely dependent on soil environmental conditions including soil temperature, soil moisture, soil texture, and the time interval since the application to the soil. Thus, it is suggested that soil environmental factors be considered in determining the timing of second or subsequent applications when necessary rather than following a fixed application schedul
Seasonal Establishment of Bermudagrass Using Plastic and Straw Mulches
Authors: Sowers R. S. , Welterlen M. S. 
Published: July 2010

AbstractBermudagrass [Cynodon dactylon (L.) Pers.] is normally established vegetatively during the early summer in the transition zone, to allow sufficient establishment time before the onset of freezing conditions in the fall. Clear polyethylene covers and straw mulches muse changes in the turfgrass microenvironment that may influence the rate of sprig establishment. The objective of this study was to evaluate the effects of barley (Hordeum vulgure L.) straw and clear polyethylene plastic mulch (0.04‐mm thickness) on the establishment of ‘Midiron’, ‘Tufcote’, and ‘Vamont’ bermudagrass from sprigs. Separate tests were conducted in the fall of 1983 and 1984 and the summer of 1984 and 1985. Summer spriggings were made in May, June, and July, months generally recommended for planting in the transition zone. Late‐season spriggings were made in August, September, and October. Plantings were made on a Sassafrass sandy loam (fine‐loamy, siliceous, mesic Typic Hapludult). Summer bermudngrass establishment was reduced under straw and polyethylene covers. Injury under plastic occurred to plantings made in May and June, which were exposed to mean soil temperatures above 41°C during the 8‐wk cover period. In contrast, plastic mulch stimulated early fall bermudagrass growth and delayed dormancy. August and September plantings remaining under plastic throughout the winter exhibited high winter survival in comparison to unmulched or straw mulched turf, and were nearly 100% established by 1 July of the following year. Spriggings under plastic planted after 20 September exhibited poor establishment by 1 July the following year. These studies showed that plastic covers can be used to extend the establishment season of bermudagrass into the fall; however, plastic covers are detrimental to summer bermudagrass establishment.
Soil Carbon Dioxide Distribution and Flux within the Open‐top Chamber
Authors: Nakayama F. S. , Kimball B. A. 
Published: July 2010

AbstractOpen‐top chamber use for exposing plants to various levels of CO2 and pollutant gases is increasing in field studies. In making a C balance of cotton [Gossypium hirsutum (L.) ‘Deltapine‐61’] for such a system, soil CO2 fluxes were observed to be significantly greater outside than inside the chamber. To find the cause, CO2 concentration was measured in the soil profile from 5‐ to 60‐cm depths of an Avondale clay loam [fine‐loamy, mixed (calcareous), hyperthermic Typic Torrifluvent]. The soil CO2 contents at the various depths sampled outside the chamber were higher than those inside the chamber. The differences in concentration were observable within 2 wk after the blower used to pass ambient of CO2‐enriched air through the chamber was turned on. The largest differences were present approximately 16 wk after the system had been in operation. Approximately 30 d was required for the soil CO2 levels inside and outside the chamber to become similar after the blower was turned off. Soil water content was not a factor causing this difference because it was nearly equal at both sites. Pressure differentials inside the growth chamber resulting from the blower operation could lead to a decrease in soil CO2 concentration and fluxes measured using the closed chamber technique.
Nitrogen Application to Cotton on Clay Soil: Timing and Soil Testing
Authors: Constable G. A. , Rochester I. J. 
Published: July 2010

AbstractWith the aim of improving utilization of N fertilizer and the flexibility of N application strategies in cotton (Gossypium hirsutum L.), five field experiments examined the response of cotton to N fertilizer, either applied before sowing or as applications before or after sowing, or both. The soils were Pellusterts with a high pH. Anhydrous ammonia was used as the N fertilizer throughout. Soil nitrate N, N uptake, and lint yield were measured in all experiments. There was a linear increase in N uptake with increased application of N fertilizer, with an average of 30% of applied N being taken up by the crop 120 d from sowing. Compared to a single presowing application, N recovery was increased by split application on two occasions, but on a further two occasions it was decreased. Split application increased lint yield on one occasion only—when compaction, waterlogging, and a long growing season allowed better utilization of sidedressed N. On all other occasions the two methods of N application produced similar yields. Therefore, sidedressing can be considered a viable practice on these soils and in this climate. Maximum yield was obtained when crop uptake was about 108 kg N/ha at 120 d from sowing, and was only partially affected by yield level. Soil nitrate N, sampled to a depth of 30 cm 4 wk before sowing, was closely correlated (r=0.86) with subsequent plant N uptake in nil fertilizer treatments. Therefore, N fertilizer requirement can be accurately determined by applying moderate levels of N before sowing, then subsequently testing for soil N on nil fertilizer strips to determine if any sidedressing is necessary. It was concluded that recovery of N fertilizer was generally poor, and improvement of this parameter has the potential to increase fertilizer use efficiency and productivity of cotton in this environment.
Comparing Sealed Chamber Digestion with Other Digestion Methods Used for Plant Tissue Analysis
Authors: Anderson D. L. , Henderson L. J. 
Published: July 2010

AbstractA sealed chamber digestion (SCD) method was developed as a rapid and simple means of tissue digestion for micro‐samples. The objective of this study was to test SCD against other digestion methods used for plant‐tissue analyses. Sealed chamber digestion, dry ash combustion, nitric/perchloric acid wet ash digestion, and sulfuric acid/hydrogen peroxide wet ash digestion methods were evaluated for efficacy of organic matter destruction for elemental analysis of plant tissues. Eight tissue standards were collected from the National Bureau of Standards, the University of Georgia, and the Everglades Research and Education Center, University of Florida. The objective of this study was to compare the previously reported SCD method with other digestion methods used for plant tissue analyses. With the exception of analysis for Al and Fe, comparison of methods of analyses indicated that SCD did not differ greatly from other digestion methods. Digestion method efficacy, as determined by nutrient analysis, appeared to reflect the plant material digestibility and digestion method. The advantages and disadvantages of the methods studied are discussed.
Crop‐Specific Thermal Kinetic Windows in Relation to Wheat and Cotton Biomass Production
Authors: Burke J. J. , Mahan J. R. , Hatfield J. L. 
Published: July 2010

AbstractPlant phenology and yield predictions require precise knowledge of crop‐weather relationships. The objective of this research is to identify an inherent biochemical trait that may provide a useful index to link the physical parameters of the environment with the plant biochemistry. We define the term thermal kinetic window as the range of plant temperatures at which the apparent Michaelis constant, Km, is at or below 200% of the minimum observed value. For example, the thermal kinetic window of wheat (Triticum aestivum L.) glyoxylate reductase for NADH is between 17.5 and 23°C, and the thermal kinetic window for cotton (Gossypium hirustum L.) is between 23.5 and 32°C. A linear relationship between the time that foliage temperatures were within their thremal kinetic window and plant biomass production was obtained for both wheat and cotton. Wheat and cotton were within their thermal kinetic windows less than 30% of the season, suggesting that approximately 70% of the growing season is available for increasing crop production either through changes in management practices or genetics. Measurements of foliage temperatures coupled with enzyme kinetics provide a unique description of the biological‐physical interactions.
Daily and Seasonal Evapotranspiration and Yield of Irrigated Alfalfa in Southern Idaho
Authors: Wright James L. 
Published: July 2010

AbstractDaily water‐use data are needed for the development of modern irrigation scheduling techniques, the optimum allocation of water and energy resources, and improved irrigation management practices. This field study was conducted to measure evapotranspiration (ET) of well‐irrigated alfalfa (Medicago sativa L.) in the arid region of southern Idaho. The relationship of ET to forage yield was also investigated. The soil was Portneuf silt loam (coarse‐silty, mixed, mesic Durixerollic Calciorthids) common to much of the region. Daily and seasonal ET data were calculated for seven growing seasons from measurements obtained with mechanical weighing lysimeters equipped with electronic load cells. Daily alfalfa ET was highly variable. It occasionally exceeded 10 mm d−1 and averaged 8 mm d−1 during peak ET periods. From April through October, measured ET averaged 1022 mm for three harvests per season for 5 yr when soil water was nonlimiting. Corresponding average forage yield was 17.6 Mg ha−1 (120 g kg−1 water content) giving an overall water requirement of 58.1 mm (depth equivalent) to produce 1 Mg ha−1 of forage (581 m3 Mg−1) for a water‐use efficiency of 17.2 kg ha−1 mm−1. Harvest period and seasonal ET appear linearly related to pan evaporation and forage yield. The actual ET of well‐irrigated, high‐yielding alfalfa may be as much as 50% greater than previous estimates indicated for southern Idaho.
Band Spacing Effects of Dual‐Placed Nitrogen and Phosphorus Fertilizers on Corn
Authors: Eghball B. , Sander D. H. 
Published: July 2010

AbstractBand spacing of P fertilizer potentially affects many factors which influence fertilizer P efficiency. Band spacing affects soil‐P fertilizer contact, probability of root‐P fertilizer contact, the time that roots contact the P fertilizer, the distribution of P fertilizer in the band, and energy requirement during application. Four field experiments were conducted to evaluate the effect of band spacing of dual‐placed N and P fertilizers on corn (Zea mays L.) grain yield and P uptake. Four band spacings of 30, 45, 60 and 75 cm were applied with three P application rates in 1983 and 1984, and five rates in 1986. Two application depths of 7.5 and 15 cm were applied in 1983 and 1984. The N rates were 200 kg N ha−1 in 1983 and 1986, and 75 and 150 kg N ha−1 in 1984. Applied P was less effective and N more effective in terms of grain yield as band spacing increased indicating a different optimum band spacing for P than for N. This caused the net effect of band spacing of dual‐applied N and P fertilizers to be nearly neutral. Seven‐leaf stage and ear‐leaf P were not affected by applied P at the high N application rate, but at the low N rate P concentrations increased as P rate increased indicating the importance of adequate N for P uptake early in the growing season. The wide band spacing of 75 cm performed poorly in grain yield response to applied N at the high N rate compared to the low N rate probably because of loss of N during application. Band spacing of N and P fertilizers did not cause significant variation in corn growth. Plants growing directly over the dual‐placed band did not yield more or less than other plants regardless of band spacing.
Ethephon Alteration of Corn Plant Morphology
Authors: Norberg O. S. , Mason S. C. , Lowry S. R. 
Published: July 2010

AbstractReduction in lodging, and plant and ear height resulting from ethephon application to corn (Zea mays L.) has been reported, but no attempt has been made to determine the influence of ethephon on internode properties and lodging. The objective of this study was to determine the influence of time and rate of ethephon application on plant and ear height, and length, diameter, and weight length−1 of internodes of corn plants. Ethephon was applied at rates of 0.0, 0.14,0.28, and 0.56 kg ha−1 at tassel elongation (TE), 6 d after tassel elongation (TE+6), and at ear elongation (EE) to Pioneer hybrid P3183 grown on Sharpsburg silty clay loam soil (fine, montmorillonitic, mesic Typic Argiudoll). Plant and ear height were reduced more by ethephon application at EE than at TE or TE+6. Increasing ethephon application from 0.0 to 0.56 kg ha−1 at EE resulted in plant and ear height reductions from 237 to 174 cm and 132 to 93 cm, respectively. Ethephon application resulted in reduced length of internodes, whereas diameter and weight length−1 increased. When applied at TE, ethephon resulted in a maximum of 48 mm reduction in internode length, 2.5 mm increase in internode diameter, and 0.017 g mm−1 increase in weight length−1; whereas application at EE resulted in a maximum of 99 mm reduction in internode length, 2.1 mm increase in internode diameter, and 0.019 g mm−1 increase in weight length−1. Stalk lodging was positively correlated to the length of Internodes 11 through 15. Application of ethephon resulted in large changes in the stalk morphology of corn plants, many of which contribute to reduced stalk lodging. Harvestable grain yield either declined or remained constant with ethephon application. These data suggest that ethephon may prove to be a useful research tool, especially for studying stalk lodging and plant architecture.
Lowland Rice Response to Urea Following Three Cowpea Cropping Systems
Authors: John P. S. , Pandey R. K. , Buresh R. J. , Prasad R. 
Published: July 2010

AbstractThe integrated use of legume green manure or legume residue with inorganic N fertilizer could offer rice (Oryza sativa L.) farmers an opportunity to reduce their expensive inorganic fertilizer inputs. A 2‐yr field experiment was conducted on an Andaqueptic Haplaquoll in the Philippines to determine the effect of cowpea [Vigna unguiculata (L.) Walp.] cropping systems on response of a subsequent rice crop to applied urea and effectiveness of several urea management practices for rice. The pre‐rice cropping systems including fallow, cowpea incorporated at the flowering stage as a green manure, and cowpea grown to maturity with either grain and pods removed or all aboveground vegetation removed prior to soil puddling for rice. The mean aboveground N content was 66 kg N ha−1 for green manure and 54 kg N ha−1 for mature cowpea without grain and pods. Rice yield responses following fallow and cowpea cropping with removal of all aboveground cowpea vegetation were similar, but mean rice grain yields were 0.9 and 0.7 Mg ha−1 higher following incorporation of green manure and residue, respectively. The green manure substituted for 34 and 54 kg urea‐N ha−1 in 1986 and 1987, respectively. Residue substituted for 44 and 50 kg urea‐N ha−1 in 1986 and 1987, respectively. Early application of urea (two‐thirds basal and one‐third at 5 d before panicle initiation) was superior to delayed application (one‐half at 14 d after transplanting and one‐half at 10 d after panicle initiation), even when supplemental N as green manure or residue was incorporated 15 d before transplanting. Cowpea grown for green manure or for grain, with incorporation of residues remaining after harvest, made similar positive contributions to rice yield, but growing cowpea to maturity offered the advantage of attaining approximately 1.0 Mg ha−1 cowpea grain production.
High‐Intensity Rainfall Rate Determination from Tipping‐Bucket Rain Gauge Data
Authors: Sadler E. J. , Busscher W. J. 
Published: July 2010

AbstractHigh rainfall rates have a major impact on agriculture through runoff, erosion, and surface crusting and on other industries through sedimentation, failure of dams, and attenuation of radio waves. Traditional techniques used to measure and record rainfall have produced event totals or hourly rates. These are unsuitable for studying short‐term impacts in brief storms (e.g., 27 mm in 30 min). The objective of this work was to develop an analytical procedure to provide millimeter per minute resolution in rainfall rate from short‐term, tipping‐bucket, rain gauge data. Counts of tips in 1‐min intervals were assembled into an array of accumulated rainfall over time during an event. A cubic spline was fitted to the accumulated rainfall curve and then differentiated to yield the rate curve. Four synthetic rainfall patterns were used to test the technique by matching original and reconstructed curves. Regression of reconstructed rates on input rates resulted in 9 ranging from 0.989 to 0.996. When applied to field data from 8 events (total: 209.5 mm) in July 1984 and 6 events (total: 139 mm) in July 1985, the technique described rainfall rate as a smooth, continuous function of time. This characteristic improves the suitability of the data for input to models of infiltration and runoff that adapt time steps to overcome numerical instability under rapidly changing conditions.