bluuebunny/crossref_metadata_2025_split huggingface dataset:
Summer Regrowth of Tall Fescue: Stubble Characteristics and Microenvironment1
Authors: Stringer W. C. , Wolf D. D. , Blaser R. E. 
Published: July 2010

AbstractStand thinning has been observed when N‐fertilized cool‐season grasses are harvested in late spring. These losses appear to be greater when hot, clear weather follows a harvest. Earlier spring cuts appear to ameliorate the stress. This 2‐year investigation examined effects of spring N at 50 and 160 kg/ha; and spring cutting (biweekly, monthly, and zero spring cuts) to 5 and 10 cm stubbles on regrowth of tall fescue (Festuca arundinacea Schreb.). Stubble canopy structure, microenvironment, and stand regrowth were examined following a June harvest at which all plots were moved at their respective cutting heights (save an unharvested check).The high N rate caused greater forage yields to be present at the June harvest. Stubble leaf area index (LAI), vegetative tiller density, and live stubble yields were not affected by N rate. Cutting during spring increased tiller density and LAI. Cutting managements had significant effects on the stubble temperafure and soil temperature that were associated negatively with stubble LA1 and tiller density. There was no detrimental effect of cutting management or N rate on stand recovery except in 1975 when lodged areas of spring accumulated swards with high N fertilization had poor regrowth. Stand losses in these area was associated with only 3 to 4% noncarbohydrates (TNC) in the stubble. Lodging is hypothesized to be partially responsible for stand losses in dense stands through detrimental effects on TNC storage and other unknown effects.
Spatial Responses of Contrasting Cotton Cultivars Grown Under Semiarid Conditions1
Authors: Bilbro J. D. 
Published: July 2010

AbstractThe southern Great Plains of Texas, New Mexico, and Oklahoma is the largest nonirrigated, semiarid cotton (Gossypiunz hirsutum L.) production area in the world. To determine if plant spacing is an important factor in crop performance under nonirrigated, semiarid conditions, a 5‐year study was conducted at Lubbock, Texas, on the effects of 5‐, 10‐, 15‐, 20‐, and 25‐cm spacings within rows 1 m apart on seven characters (lint yield, lint percentage, bolls/plant, boll size, 2.5% span length of fiber, fiber strength, and coarseness). The soil was fine‐loamy, mixed thermic Aridic Paleustalf or Paleustoll. Two cultivars, ‘ Paymaster 111’ and ‘ Stripper 31’ were used.Differences among years were significant for all characters and were larger than differences between cultivars or among spacings. Year X cultivar, and year X spacing interactions were significant for most characters, but the cultivar X spacing interaction was significant only for bolls/plant. The second‐order interaction was significant for only fiber coarseness. The two cultivars differed significantly for all characters except lint yield and lint percentage. Paymaster 111 produced larger bolls and longer, stronger fiber; whereas, Stripper 31 had more bolls/plant and coarser lint. Spacing affected every character, except fiber strength, in at least 1 year. Regression analyses of lint yield‐spacing relationship indicated that spacings of about 16 to 19 cm were optimum in the years when yields were near average (250 to 300 kg/ha). When yields were much above average (over 600 kg/ha), the 5cm spacing was superior. In the year when yields were much below average (less than 100 kg/ha), there was no significant yield‐spacing relationship. Spacing had no significant effect on fiber strength in any year. Bolls/plant increased linearly as spacing was increased. The effects of spacing on lint percentage, fiber length, and micronaire were not consistent. The 5‐cm spacing produced the smallest bolls.The overall results indicate that under dryland conditions in the southern Great Plains, the optimum within‐the‐row spacing of cotton plants is probably about 17 cm if the distance between rows is 1 m.
Maize Culture in Reed Canarygrass Sod to Renovate Municipal Wastewater Effluent1
Authors: Marten G. C. , Linden D. R. , Larson W. E. , Clapp C. E. 
Published: July 2010

AbstractField conditions that accompany conventional maize (Zea mays L.) culture may not permit adequate infiltration of wastewater effluent needed for optimum yields. Two experiments with randomized complete block designs were conducted over a 3‐year period on effluenttreated soils to assess the effects of suppressing reed canarygrass (Phalaris arundenacea L.) with several types and rates of herbicides on (a) yields of interplanted maize grain and fodder; (b) total crop yields and N removal by maize‐reed canarygrass combinations; (c) feed quality of interplanted maize; (d) water infiltration capacity of the Typic Hapludoll soil; and (e) the N concentration in the soil water at the bottom of the root zone (just above the water table).Herbicidal suppression of 60% of the reed canarygrass was necessary to obtain maximum grain and fodder yields of the interplanted maize. This degree of suppression was achieved consistently by glyphosate (N‐(phosphonomethy1) glycine) applied at 0.56 kg AI/ha. This treatment holds most promise for use in the type of culture system outlined because: 1) This was the only treatment that suppressed at least 60y0 of the reed canarygrass without completely killing it, 2) The soil under this treatment was capable of sustained infiltration rates of 1.7 cm/hr to prevent the ponding that occurred in killed grass sods, 3) One application of glyphosate was effective over a 2‐year penod. Annually‐applied paraquat (1,l'‐dimethyl‐ 4,4'‐bipyridinium dichloride) at 0.56 kg AI/ha also provided satisfactory (but sometimes lower) yields of maize interplanted in reed canarygrass.Total N removal by maize‐reed canarygrass combinations was maximum when the grass was not suppressed by herbicides. This was due to the superior capacity of reed canarygrass compared to maize to remove N from effluent‐treated soils. The N concentration in the soil water also reflected N removal by the combined crops, in that minimum soil water N occurred when N removal by the crops was maximum. An effluent‐renovation croping system in which maize is interplanted in herbicide unsuppressed reed canarygrass will remove more N but could lead to much lower maize yields than a system where the grass is suppressed.Feed quality of maize ears or fodder was not influenced by degree of reed canarygrass suppression, except for two occasions where the crude protein concentration of fodder and/or ears was reduced, and one occasion where the fodder digestibility was increased, when the grass herbicide‐suppressed or was partly suppressed.
Nitrapyrin and Etradiazole Effects on Nitrification and Grain Sorghum Production1
Authors: Westerman R. L. , Edlund M. G. , Minter D. L. 
Published: July 2010

AbstractNitrification inhibitors offer the potential to improve efficiency of N applications when climatic and soil conditions are favorable for leaching and/or denitrification.Grain sorghum [Sorghum bicolor (L.) Moench] was grown in five field experiments at three locations during 1976, 1977, 1978, and 1979, with two nitrification inhibitors and three N sources. Four of these five experiments received supplemental irrigation water. Soil textures at experimental locations were sandy, silt, and clay loams and pH's ranged from 5.2 to 7.8. Nitrification inhibitors evaluated were nitrapyrin and etradiazole. Sources of N were anhydrous ammonia and urea in 1976, urea and urea‐ammonium‐nitrate (UAN) solution in 1977, and UAN hi 1978 and 1979. Treatments consisted of 0.56 kg/ ha of nitrapyrin and multiple rates of etradiazole applied with varying rates of N. Soil samples were taken from selected experiments at varying time intervals and analyzed for urea‐, NH4+−, NO3−, and/or NO3−‐N depending on the year and experiment. Field plots were harvested with a conventional combine and yields were analyzed statistically to assess beneficial effects of treatments.Soil N forms were altered by nitrification inhibitors at various tune intervals during the growing seasons. However, the changes observed did not lead to increased efficiency of applied N or to an increase in yield of grain sorghum. It was concluded that little if any benefit can be derived from nitrification inhibitors in grain sorghum production in Oklahoma.
Response of Determinate and Indeterminate Soybeans to varying Cultural Practices in the Northern USA1
Authors: Beaver J. S. , Johnson R. R. 
Published: July 2010

AbstractDeterminate soybean [Glycine max (L.) Merr.] cultivars adapted to the northern U.S. soybean growing region have been developed and released in recent years. The purpose of this research was to compare the response of determinate and indeterminate soybean cultivars to varying cultural practices. The determinate cultivars, ‘Gnome’ and ‘Elf’, and the indeterminate cultivars, ‘Beeson’ and ‘Williams’, were grown at two Illiiois locations in planting dates ranging from early May to early July. The soil was Flanagan silt loam (Acquic Argiudoll) at Urbana and Cisne silt loam (Mollis Albaqualf) at Brownstown. Within each planting date, cultivars were planted in 80, 50, and 20 cm row widths. A separate seeding rate study was conducted with the determinate cultivar Elf, using seeding rates of 350,000, 500,000, and 650,000 seeds/ha in both 76 and 20 cm row widths.Planting date contributed most to variation in seed yield. Seed yield in central Illinois decreased an average of 33% as planting date was delayed from early May to early July. Seed yield of the indeterminate cultivars declined steadily after the early May planting date, whereas, seed yield of the determinate cultivars did not decrease until planting date was delayed past early June. The indeterminate cultivars showed a linear decline in plant height and main stem node number as planting date was delayed, whereas, plant height and main stem node number of the determinate cultivars were greatest in early June plantings. Lowest pod height of the determinate cultivars planted after mid‐June or in drought‐prone soils was sufficiently close to the soil surface (less than 10 cm) to cause concern about excessive harvest losses. Seed yields of both the determinate and indeterminate cultivars increased significantly (9 and 5% at Urbana and Brownstown, respectively) as row widths were narrowed from 80 to 50 cm, whereas, seed yields in 50 and 20 cm row widths did not differ.The determinate cultivar Elf exhibited the ability to perform well over plant densities at harvest ranging from 279,000 to 494,000 plants/ha. A seeding rate of 400,000 to 500,000 seeds/ha for determinate cultivars appears sufficient to maximize seed yield, reduce potential harvest losses due to low basal pod height, and insure adequate and uniform stands in unfavorable seedbeds.
Forage Quality Response of Four Lovegrasses to Stage, Interval, and Season of Harvest1
Authors: Voigt P. W. , Horn F. P. , Dewald C. L. 
Published: July 2010

AbstractDespite the importance of weeping lovegrass, Eragrostis curvula (Schrad.) Nees, in Argentina, South Africa, and to a lesser extent in the United States, much remains to be learned about its forage quality. The objectives of this research were to evaluate: a) forage quality of four weeping lovegrass entries, b) seasonal patterns of forage quality, and c) effect of stage of first growth and age of regrowth on forage quality.Field experiments were conducted on an Enterprise loam (Thermic Typic Ustochrepts) soil at Woodward, Oklahoma. ‘Morpa’, ‘Ermelo’, common, and 673 were harvested under three managements: a) jointing stage and four subsequent 28‐day intervals, b) heading stage and three subsequent 34day intervals, and c) anthesis stage and two subsequent 45‐day intervals. In vitro dry matter disappearance (IVDMD), crude protein, cell contents (CC), hemicellulose, cellulose, and permanganate lignin (PL) were determined. Results were analyzed by ANOVA and regression procedures.Morpa and Ermelo were similar and higher in IVDMD than common and 673. This higher IVDMD was correlated with lower PL and dry matter contents. Maturity differences among entries did not account for all entry variability in forage quality. Nongenetic correlation coefficients showed that high IVDMD was associated with high crude protein and CC and low cellulose, PL, and dry matter. Seasonal trends in forage quality showed that from jointing to anthesis IVDMD declined 0.46 percentage units per day. Following the initial harvests, IVDMD continued to decline at 0.02 percentage units per day during the remainder of the summer, despite equal interval regrowth harvests. Similar patterns were found for crude protein and CC. Hemicellulose also decreased from jointing to anthesis but then increased during regrowth harvests. Cellulose and PL increased from jointing to anthesis, but showed only small seasonal changes during regrowth harvests. Increasing age of regrowth resulted in lower IVDMD (—0.28 percentage units per day), crude protein, and CC, and higher cellulose and PL. However, changes were more gradual than from joint to anthesis.
Equipment to Mix Chemical Additives with Anhydrous Ammonia during Application to Soil1
Authors: Huber D. M. , Karamesines P. D. , Warren H. L. , Nelson D. W. 
Published: July 2010

AbstractEtridiazole (5‐ethoxy‐3‐trichloromethyl‐1,2‐4‐triadozole) effectively reduces leaching and denitrification losses of ammoniacal N by inhibiting nitrification; however, it is not soluble or stable in anhydrous ammonia (NH3). Many other potentially beneficial agricultural chemicals are not soluble in or compatible with NH3. To overcome the need for a separate application of some nitrification inhibitors, trace elements, and plant growth regulators, a simple device was constructed to facilitate the simultaneous application of low volume solutions with NH3. This device consists of an adjustable positive displacement pump operated off the tractor electrical system and a black iron injection pipe positioned between the N flow regulator and distributor (NH3 manifold). The additive is carried from its reservoir to the pump and from the pump to the injection pipe in Tygon or plastic NH3 discharge hose. In this arrangement, potentially corrosive additives bypass expensive valves and flow devices, and are mixed in the NH3 stream just prior to injection into soil. Advantages include direct placement of the chemical additive with NH3, reliability, adaptability to most existing field equipment, simple design, and ability to partially treat a field. This equipment was tested by adding nitrapyrin [2‐chloro‐6‐(trichloromethyl)pyridine] and etridiazole (nitrification inhibitors) to the NH3 stream and measuring the total recovery of materials and their distribution between several applcator knives. Recovery of the inhibitors was 96 to 100% with distribution between knives on the applicator ± 7.7%. Simultaneous application of these nitrification inhibitors with NH3 applied to field soil cropped to wheat (Triticum aestivum L.) demonstrated the effectiveness of the equipment in adding the nitrification inhibitors to NH3.
Conventional and Suspension Limestone Influence on Soil Chemical Properties and Corn and Soybean Yields1
Authors: Bertsch P. M. , Alley M. M. 
Published: July 2010

AbstractConventional and suspension limestone materials prepared from identical limestone rock were evaluated to compare their reaction rates for neutralizing soil acidity. Measurement of the limestone materials influence on N NH4OAc extractable Ca and Mg and N KCl exchangeable Al, soil pH, and crop yields were utilized to study reaction rates. Field plots were established on a Goldsboro sandy loam (Aquic Paleudults) and an Emporia loamy sand (Typic Hapludults) in the Coastal Plain region. Corn was the indicator crop for the Goldsboro soil, while soybeans were grown on the Emporia soil. Treatments ranged from 0 to 13.94 and 0 to 4.48 metric tons/ha on the Goldsboro and Emporia soils, respectively. Initially, extractable soil Ca and Mg increased and exchangeable Al decreased more rapidly with suspension limestone applications than with conventional treatments. Regardless of material, lime rates of 2.24 metric tons/ha and greater increased surface soil pH 2 weeks after limestone application on both soils. Sixteen weeks after lime treatment, increases in extractable Ca and Mg and soil pH, and decreases in exchangeable Al were approximately equal for both materials. Yield responses varied with lime treatments at both locations.
Influence of Concentrations of K and Mg in Nutrient Solutions on Sorghum1
Authors: Ologunde O. O. , Sorensen R. C. 
Published: July 2010

AbstractSeveral interactive effects of K and Mg are present both in plants and soils. Very limited information is available on the interaction of these two elements in sorghum [Sorghum bicolar (L.) Moench] plants. Thus a greenhouse experiment was conducted in sand culture to determine the main and interactive effects of K and Mg in the medium on growth and composition of sorghum plants.Nutrient treatments included seven concentrations each of K as KCI, and Mg as MgCI2. Seventeen of the possible 49 treatment combinations were used in a central composite factorial design with two replications. A sorghum hybrid (‘RS 671’), its male (‘Tx 415’), and female (‘Redlan’) lines were used. Aboveground parts of plants were harvested at 25, 50, and 75 days after emergence.The three sorghums showed similar effects for most treatments. Dry matter production was not affected by concentrations of K and Mg until 50 and 75 days after emergence, respectively. At final harvest, maximum top dry matter production was obtained at the optimum rates of 195 and 38 ppm of K and Mg, respectively. Effects of K were not affected by concentrations of Mg and vice versa.As long as the absolute amounts of K and Mg in the growth medium were adequate to meet the demands of the plants, the K/Mg ratio in the growth medium varied widely without causing any adverse effect on dry matter production of the plants.Plant nutrient concentrations were determined by rate of growth and consequent nutrient dilution. However, high levels of K in the growth medium reduced plant Mg concentrations. Also increased rates of applied Mg increased the concentrations of P in the plants.Increases of K/Mg ratio in the growth medium were associated with reductions in Mg, Ca, and P concentrations in the plant, but the sum (K + Mg + Ca) remained constant.These results show that K is probably more critical than Mg in the nutrition of sorghum, but low levels of both created growth problems particularly as the growth period of the plant exceeded 50 days. Two parent lines and a hybrid showed limited differences in K and Mg nutrition. The K/Mg ratio in the growth medium was not useful in predicting amount of growth.
An Enzyme Kinetic Equation to Estimate Maize Development Rates1
Authors: Kiniry J. R. , Keener M. E. 
Published: July 2010

AbstractWhile use of thermal units to predict development rate is very old, nearly all thermal unit equations are empirical and have no theoretical basis. The poikilotherm equation is unique in that it has a theoretical basis and accounts for both high and low temperature nonlinear development rate responses; however, this equation had never been applied to field grown plants. In this study, the equation, along with more traditional thermal unit equations, was applied to field grown maize (Zea mays L.).Three hybrids of maize were grown in two plantings at two locations in each of 2 years. The coefficient of variation across mean unit sums for each planting was used as the criterion for comparing six other equations with the poikilotherm equation. Other equations used were the growing‐degree‐day (GDD) 40, the GDD 50, the 50 to 86 cut‐off, the heat‐stress, the Ontario corn heat unit equations, and day count.The GDD 40 equation best described the planting to tassel initiation interval. Silking appeared to be delayed by high temperatures, thus the tassel initiation to silking interval was best described by the heatstress equation. There appeared to be no difference between different thermal unit equations for the silking to black layer formation and planting to black layer formation intervals. Even though the poikilotherm equation was based on physiology of the plant, it was no better than the other methods of accumulating heat units.
Salt and Water Stress Effects on Germination of Guayule Seeds1
Authors: Miyamoto S. , Sosnovske K. , Tipton J. 
Published: July 2010

AbstractIn view of developing domestic rubber productions, guayule (Parthenium argentatum G.) is receiving renewed interest; however, necessary cultural practices have not been well established, especially under saline conditions. Studies were performed, therefore, to evaluate salt and soil water stress effects on seed germination. The test materials included four USDA selections (11646, 11604, 11633, and A48118) and one cultivar (593). Petri dish solution cultures were used for evaluating salt effects, and two sandy soils (Typic Torrifluvents and Typic Torripsamments) placed in petri dishes were used for studying soil water stress effects. Results indicate that seed germination may be reduced by approximately 25%, due to salinity of salt solutions ranging from 7 to 19 mmho/cm with a descending order of tolerance of 11646, 593,11604 = 11633, and A48118. Selection 11646 showed excellent characteristics as well as high salt tolerance. Specific ion effects were insignificant when tested in salt solutions having mixed ion compositions. Soil water stress needs to be controlled at less than about 0.8 bar if germination is to be accomplished without adverse effects of water stress.
Gibberellic Acid Influence on Aged and Unaged Barley Seed Germination and Vigor1
Authors: Huber Thomas A. , McDonald Miller B. 
Published: July 2010

AbstractGibberellic acid (GA) is presently used to break dormancy of cereal grains prior to germination testing. The increased use of vigor testing has led to an interest in the applicability of GA in breaking dormancy prior to vigor testing. The present study identifies the vigor criteria which are most suitable for the incorporation of GA in the testing procedure. The influence of GA (10 μM), artificial aging (41 C, 100% RH, 4 days), initial vigor level (high, medium, and low) and various interactions of these factors on the germination and vigor assessment of ‘Himalaya’ barley (Hordeum vulgare L., cv. Himalaya) seeds were determined. High vigor seeds exhibited higher germination, higher dry weight production and longer mean plumule than did medium and low vigor seeds. Artificial aging decreased germination of all vigor levels, with the greatest decrease exhibited by medium and low vigor seed lots. Artificial aging also decreased the mean plumule length and dry weight production. Exogenous GA slightly decreased the germination of aged and unaged seeds at Day 7, but not at Day 4. This decrease, however, did not affect germination test interpretations. Gibberellic acid also increased the mean plumule length but did not affect dry weight production or the number of abnormal seedlings. We conclude that physiological levels of GA did not adversely affect germination test results. Furthermore, GA did not affect the interpretation of vigor tests when measuring germination (7 and 4 day count) or dry weight production. However, GA did increase plumule length which suggests that this is a poor vigor criterion when using GA to break dormancy of barley seeds.