bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ephedra Seed Germination1
Authors: Young James A. , Evans Raymond A. , Kay Burgess L. 
Published: July 2010

AbstractGermination of seeds of gray ephedra (Ephedra nevadensis Wats.) and green ephedra (E. viridis Cov.) must be better understood for propagation on southwestern rangelands of the United States. Investigations were conducted on germination of these species in a wide range of constant and alternating temperature regimes and in different osmotic potentials. Both species germinated over a relatively large range of temperatures. Optimum germination for gray ephedra occurred at constant temperatures ranging from 5 to 20 C and at alternating temperatures of 20/25 C. Green ephedra had optimum germination when combinations of 16 hours of cold temperatures (2 or 5 C) and 8 hours of moderate warm temperatures (15 to 25 C) were followed. Gray germinated faster than green ephedra. Seed storage at room temperature for 12 months after maturity reduced germinability (drastically in the gray ephedra). Low osmotic potentials (created with NaCl or polyethylene glycol) reduced germination more in the green than the gray ephedra seeds. Germination of both species should not limit their use in revegetation except on salty soil in the case of green ephedra.
Relationship Between Corn Yield, Expressed as a Percentage of Maximum, and the N Percentage in the Grain. II. Diagnostic Use1
Authors: Pierre W. H. , Dumenil Lloyd , Henao Julio 
Published: July 2010

AbstractThe purpose of this study was to develop a procedure for determining the amount of N fertilizer needed by corn (Zea mays L.) for maximum yield and economic optimum yield based on the relationship between the relative yield of corn, expressed as a percentage of maximum yield, and the N percentage in the grain. The three major steps in the procedure are: (a) determining the maximum potential yield and yield increase from the relative yield — percent N relationship and the present yield, (b) determining the N‐requirement index (NRI) for different initial relative yields, and (c) calculating the total N requirement.Two procedures were developed for estimating the NRI, the N required per unit of yield increase, from different initial relative yield levels to maximum or economic optimum yields. One involved simple computations using the treatment means from 13 site‐years of experimental data. The other utilized the individual regressions of yield on N fertilizer from the same experiments to calculate the NRI's to the same marginal productivity point on each site‐year's regression. Good agreement was obtained between the two procedures.The average NRI's were found to vary from approximately 7.5 kg/q at 90% of maximum yield to 3.5 kg/q at 45% of maximum yield. Evidence was obtained showing the desirability of using NRI values for comparing the efficiency of N use under different environmental and management conditions.Factors that may affect the relative yield — percent N and the NRI — initial relative yield relationships are discussed briefly. Also, the need for further research, expecially on the effect of different hybrids, is suggested.
Nitrogen and Chloride Uptake by Irrigated Russet Burbank Potatoes1
Authors: Saffigna P. G. , Keeney D. R. 
Published: July 2010

AbstractPotato production has become a major agricultural enterprise in the central sand plain of Wisconsin. However, little information is available on the effects of irrigation and fertilization practices on dry matter and N accumulation. This field study was established to determine the effect of reducing irrigation and fertilizer N on the dry matter, and the N and Cl in potatoes (Solanum tuberosum L., var. ‘Russet Burbank’) grown on a Plainfield loamy sand (Typic Udipsamment: sandy, mixed, mesic).Two basic treatments were used. The conventional treatment approximated current recommendations for irrigated potatoes and received 260 kg N/ha (as NH4NO3) in four applications and 45 an irrigation as 2.4 cm applications every 5 days. The improved treatment was intened to minimize leaching of NO3‐N. It received 170 kg N/ha in 10 applications (one as S‐coated urea and nine as NH4NO3) and 27.0 cm irrigation as 1.0 cm applications every 3 days. Chloride (as KCl) accompanied N on a 1:l weight basis. Plants were sampled weekly and analyzed for dry matter, total N, NO3‐N, and Cl.Plants accumulated 3 to 4 kg N/ha/day from 20 to 70 days after emergence. The maximum N uptake for the whole plant (tops and tubers) was 170 to 250 kg N/ha about 90 days after emergence. The maximum uptake of N in the tops was 125 and 80 kg N/ha in the conventional and improved treatments, respectively. Tuber yields and N uptake were similar between treatments with tubers containing 1.3 to 1.5% N most of the growing season and 130 to 140 kg N/ha (27 to 30 kg N/100 q) at harvest. Plants accumulated 115 to 145 kg Cl/ha, mostly in the tops (90 to 120 kg Cl/ha) with 25 to 40 kg Cl/ha in the harvested tubers.Nitrate‐N levels were low (<100 mg/kg) in tubers at all samplings. Nitrate‐N was >2,000 mg/kg in the tops during the first half of the growing season and accounted for 10 to 25% of the total N. Due to competitive antagonism, Cl reduced NO3‐N concentration in tops and petioles, and total N in tops and tubers.The results from this study show that tuber growth and N content were not appreciably affected by substantial reductions in the quantity of fertilizer N (90 kg N/ha) and irrigation (18 cm) applied although foliage dry matter and N accumulation were reduced. However, the additional effort required to effect this small saving in N fertilizer cannot currently be justified.
Maximizing Production Potential of Tall Fescue1
Authors: Kroth Earl , Mattas Richard , Meinke Louis , Matches Arthur 
Published: July 2010

AbstractTall fescue (Festuca arundinacea Schreb.) is grown primarily for forage on over 162,000 ha in Missouri. Fescue is managed for spring and summer pasture and for both seed and fall forage production. Spring and fall growth is often stockpiled for late fall and winter feed. This study was conducted to determine the effects of rate and time of N applications and forage management on seed yield, and on quality and yield of forage.Plots were layed out on established stands of tall fescue on Gerald, Lebanon and Edina silt loams (Umbric Fragiudalf, Typic Fragiudalf, fine mixed mesic; Typic Argialboll, fine montmorillonite, mesic, respectively.) Nitrogen rates on Gerald and Lebanon soils (Southwest Missouri) were 0, 33, 67, 101, and 134 kg/ha in different time combinations, including December, March, June, and August. Forage management included: (a) removal after seed harvest and again in December, (b) stockpile after seed harvest, harvest in December. Nitrogen rates on Edina silt loam (North Missouri) were 0, 67, and 134 kg/ha in different time combinations, including December, March, July, and August. In addition to the two management systems listed above, forage was round baled at the early head stage and harvested again in December. Effects of treatments were evaluated by seed yield and yield, crude protein, and IVDMD of the forage.Nitrogen for seed production was more efficient when applied in December, while March was a better time to apply N for forage production. One‐hundred‐one kg/ha was the optimum rate for both purposes. Severe lodging was caused by 134 kg/ha N at both locations. Failure to remove plant residue after seed harvest reduced seed yields the following year from 42 to 45%. These residues average 7.0% crude protein and 52% IVDMD. Forage round baled in the early head averaged 10.9% crude protein and 52% IVDMD. August was the best time to apply N for fall forage production and 101 kg/ha was the optimum rate.
Influence of Conservation‐Tillage Environments on Growth and Productivity of Corn1
Authors: Mock J. J. , Erbach D. C. 
Published: July 2010

AbstractResearch on growth responses of corn (Zea mays L.) to environmental conditions associated with conservation‐tillage systems has not been extensively conducted. Therefore, the objectives of this study were to evaluate effects of various tillage systems (fall moldboard plow, till‐plant, no‐till ridge with and without previous‐crop residue) and early planting on growth and productivity of several corn genotypes (including two heterogeneous breeding populations that were improved for cold tolerance by recurrent selection). The experiment was conducted for 2 years on a loam soil (Typic Hapludoll), and planting dates were 1 Apr. 1974, and 30 Apr. 1975. Conservation‐tillage systems were associated with lower midafternoon soil temperatures (at 5‐cm depth) during the early growing season and more variability in depth of seed placement. Also, seedling and juvenile plant growth, final plant densities, and grain yields were lower in conservation‐tillage systems. These differences were accentuated in the early planting environment of the 1974 experiment. With a relatively normal planting date and equal final plant densities (the not affected by tillage treatment. There was no interaction between tillage method and com genotype. Usually, genotypes with vigorous seedling and juvenile plant growth and high final plant stands produced highest grain yields in all tillage environments. In the central U.S. Corn Belt, therefore, optimum corn grain yields in conservation‐tillage environments will be obtained by the use of planters that assure uniform seed depth and genotypes that display vigorous plant growth and development.
Influence of Plant Stage at Initial Harvest and Height of Regrowth at Cutting on Forage Yield and Quality of Timothy and Orchardgrass1
Authors: Mislevy P. , Washko J. B. , Harrington J. D. 
Published: July 2010

AbstractThe need to obtain the best compromise between yield and quality has been recognized for years. The object of this study was to evaluate the influence of initial harvest at various growth stages and height of regrowth (all cuttings after initial harvest) at cutting on forage yield and quality of ‘Climax’ timothy (Phleum pratense L.) and ‘Pennlate’ orchardgrass (Dactylis glomerata L.). First growth of these grasses was harvested at each of the following stages: (a) transition (changing of apical meristem from vegetative to reproductive growth), (b) boot, and (c) anthesis. Following each initial harvest stage, regrowth was removed throughout the growing season at each of the following plant heights: 10 to 15 cm, 20 to 25 cm, 30 to 36 cm, 41 to 46 cm, and 51 to 56 cm. This field investigation was conducted during 1970 and 1971 on a fine, loamy, mixed, mesic Typic Hapludults (Murrill series) at the Agronomy Research Farm near Rock Springs, Penn.Delaying the first harvest of timothy and orchardgrass from the transition to anthesis stage resulted in increased yield and estimated total digestible nutrients (TDN). However, total seasonal regrowth, total TDN of regrowth, total digestible protein, and total digestible protein of regrowth decreased significantly (P≤0.05). Allowing plants of both species to attain heights of 20 to 36 cm, with few exceptions, produced highest total and regrowth forage yield, TDN, and digestible protein. However, frequent removal of regrowth, at a plant height of 10 to 15 cm, resulted in significantly (P≤0.05) lower yields and encouraged weed encroachment. These data indicate first harvest forage removal at the transition stage, followed by regrowth removal each time plants attain a height of 20 to 36 cm results in highest production of quality forage as measured by total seasonal regrowth, total TDN of regrowth and total digestible protein.
Fitting Plants Nutritionally to Soils. I. Soybeans1
Authors: Brown J. C. , Jones W. E. 
Published: July 2010

AbstractPlant species and varieties within species differ in their response to mineral stresses and toxicities. To achieve maximum yields, the plant and the soil must be compatible. In the past, the soil has been changed to fit the plant. In this study, we consider changing the plant to fit the soil, recognizing that plant species and varieties within species have specific nutrient requirements. Ten soybean (Glycine max (L.) Merr.) varieties, representing the germplasm currently used in soybean production in the United States, were subjected to Fe, Zn, and Cu stresses; and Mn and Al toxicities to determine their nutrient requirements or tolerance to mineral elements. Seven soils, which had produced the above nutrient stresses and toxicities in other crops, were used in this study. The soybean varieties showed a differential response to Fe stress by developing severe (‘Forrest’), moderate (‘Hodgson’), or no Fe chlorosis (‘Bragg’). Leaves dropped from Forrest and Bragg soybeans as they developed severe Mn toxicity symptoms. In contrast, ‘Lee’ soybean developed only slight Mn toxicity symptoms. Most soybean varieties grew well when subjected to Zn and Cu stresses, or when grown on Al‐toxic soil. Care should be taken to select the proper soybean variety to be grown on soils where Fe stress or Mn toxicity may be a problem.
Effects of N, P, and K Fertilization on Yield and Quality of Tall Fescue Forage in Winter1
Authors: Balasko J. A. 
Published: July 2010

AbstractUse of tall fescue (Festuca arundinacea Schreb.) regrowth to extend the grazing season into late fall and winter is becoming increasingly popular in middle‐latitude regions of the USA. Few studies have been reported, however, that deal with factors influencing yield and quality of regrowth forage in winter. A field study was begun in October of 1971 to measure the effects of N, P, and K fertilization on yield and quality of tall fescue regrowth in late fall and winter. Eight fertility regimes were established in each of four replications. These were: 1) N applied at 60 kg/ha in spring and after each of three summer harvests, 2) P applied at 30 kg/ha in spring and in late summer, 3) K applied at 60 kg/ha in spring and in late summer, 4) to 7) the four possible combinations of the above three treatments, and 8) no fertilizer treatment. Forage from all plots was harvested in mid‐May, early July, and mid‐August and then in either mid‐December or mid‐January. In 1971 when the experiment began, all plots were harvested on 9 October rather than mid‐August and then in either mid‐December or mid‐January. Nitrogen fertilization increased yield and concentrations of in vitro digestible dry matter, total nonstructural carbohydrate, K, Mg, and N in the late fall and winter harvested forage and decreased concentrations of dry matter and Ca. Yield and concentration of quality components decreased less in N fertilized forage than in unfertilized and P and K fertilized forage as harvest was delayed from December to January. Phosphorus fertilization had little effect upon yield and quality components. Potassium fertilization decreased both Ca and Mg concentrations. Results suggest that winter forages of sufficient quality to meet most of the nutritional needs of many classes of livestock in mid‐latitude regions of the U.S. may be obtained by manipulating summer and/or fall harvest dates and fertilization rates. Supplementation of regrowth forage with Na and Mg and possibly with P during late winter months would be required.
Components of Developing Soybean Seeds: Oil, Protein, Sugars, Starch, Organic Acids, and Amino Acids1
Authors: Yazdi‐Samadi Bahman , Rinne R. W. , Seif R. D. 
Published: July 2010

AbstractA thorough chemical analysis on the composition of developing soybean [Glycine max (L.) Merr.] seeds does not appear in the literature. Several investigators have determined protein and oil, while others have determined the carbohydrates. The purpose of this study was to make a thorough analysis of the developing soybean seed, including protein, oil, sugars, starch, organic acids, and amino acids. Soybean seeds from ‘Harosoy 63’ grown in the field and ‘Steele’ grown in the greenhouse were analyzed for these components from 10 days after flowering, at 10‐day intervals, to maturity. These components accounted for 75% of the dry weight of the seed. The remaining dry weight of the seed is in cellulose, crude fiber, and ash. Oil and protein (mg/seed) increased until maturity in Harosoy 63 but leveled off before maturity in Steele. When oil and protein are expressed as percentage dry weight, similar patterns were observed for both cultivars. The sugars glucose, fructose, galactose, sucrose, raffinose, and stachyose were all detected in the soybean seed. Raffinose and stachyose were not detected until 50 and 40 days after flowering in Harosoy 63 and Steele, respectively. Starch reached a maximum value of 14.6 mg/seed in Harosoy 63 and 7.9 mg/seed in Steele at 40 and 30 days after flowering, respectively. Starch then declined sharply in both varieties. The water soluble polysaccharide (mg/seed) fraction showed a steady rise for both varieties throughout the study, but declined as percent of dry weight. The concentration of organic acids was low, with glycolic, succinic, malic, and citric being detected. Citric acid was detected in the greatest quantity. Seventeen amino acids and one unknown component were detected in the amino acid analysis. Of the amino acids detected, seven showed increases while three amino acids as well as the unknown showed decreases. Analysis of variances and standard error of the mean were performed on the data for each trait in each variety using a completely randomized design with specific tests for linear regression over the 70 or 60 days after flowering. In addition, quadratic regression was run for starch. Simple correlation coefficients were also found between all the traits studied and can be obtained upon request.
Soil Crusting and Emergence of Wheat Seedlings1
Authors: Hadas A. , Stibbe E. 
Published: July 2010

AbstractSoil crusting is usually referred to be the cause of impaired wheat (Triticum aestivum L.) stands in the Negev region of Israel. The soils in this region vary from mixed hyperthermic, typic Ustipsamment soils to fine loamy, mixed hyperthermic typic Ustorthent soils.The major objective of the work carried out was to estimate and analyze the soil crusting phenomena under field conditions and as a secondary objective to study and analyze wheat seedlings behavior under field and laboratory conditions.Resistance to penetration of natural soil crusts, measured by penetration from underneath the crust, and its dependence on water content and seed bed preparation methods (disking vs. plowing) were determined. These measurements were collected in a field survey carried out during early winter following the first rain that initiated both wheat germination and a sequence of soil slacking and subsequently, as the soil dried out, crusting. It was found that natural crust resistance to penetration was greater for those formed on disked plots than on plowed plots.In laboratory trials, using a sandy silt loam (typic ustipsamment) soil, crusts were formed by simulated rainfall (intensity of 10 mm/hour, rainfall applications of 5, 10, and 30 mm in one or two simulated rainstorms). These crusts were found to be less penetrable than the natural ones for the same soil under natural field conditions at the same water contents.Wheat seedling penetration of soil crusts was evaluated under laboratory conditions, whereas projected penetrability of crusts under field conditions was based on an assumed water potential and subsequent coleoptile thrust in the region of the seedlings. These projected values suggested that crusting in the field may not be the cause for a bad stand, except under extremely adverse conditions. These projections illustrate the urgency of including dynamic considerations of seedling performance in the future studies of small grains germination and emergence under and through crusting soils.
Autumn‐Winter Yield and Quality of Tall Fescue1
Authors: Ocumpaugh William R. , Matches A. G. 
Published: July 2010

AbstractStockpiling, an agricultural practice that extends the grazing season into the winter by accumulating growth of standing forage during the growing season, is practiced successfully in numerous regions of the world. The objectives of this 2‐year experiment were to determine, for tall fescue (Festuca arundinacea Schreb.), the effects of spring‐summer defoliation and autumn‐winter environmental conditions on the quantity and quality of forage available during the autumn and winter. Three sets of plots were defoliated during the spring and summer at 4, 8, and 10‐week intervals so that the last defoliation occurred on 9 August of each year. A different subplot of each set of preconditioned plots was then harvested at approximately weekly intervals through November. An additional set of preconditioned plots (8‐week defoliation treatment) were harvested at approximately weekly intervals from the end of November into February. The soil was a fine, montmorillonitic, mesic Udollic Ochraqualfs. More frequent defoliations (4 weeks vs. 8 to 10 weeks) reduced the yield of dry matter in the springsummer period by 30 to 40%, but had no effect on autumn yields. Forage from frequently defoliated plots was of higher quality during the spring and summer than less frequently harvested plots, but frequency of defoliation did not affect the quality of autumn stockpiled fescue and had little effect on autumn yields. Dry matter production in the autumn was directly related to the autumn‐accumulated rainfall (Y = 52.7 + 62.1 X, r = 0.988 for 1971 and Y = —1068 + 163.6 X, r = 0.934 for 1972). Freezing temperatures in early November stopped autumn growth at about 1,000 kg/ha in 1971 and 1,800 kg/ha in 1972. After freezing temperatures, there was a 25 kg/ha/week decrease in harvestable dry matter. The crude protein content decreased steadily throughout the autumn‐winter period, and after growth stopped the rate of decrease averaged about 0.1 percentage unit/week. The in vitro dry matter digestibility of stockpiled fescue remained fairly constant (63 to 68%) from September to early November. After growth was stopped by freezing temperatures in November, digestibility decreased about 1.0 percentage unit/week. The potassium content of the autumn‐grown forage decreased at a linear rate of about 0.1 percentage unit/week throughout most of the autumn‐winter period and, in 1971‐72, decreased to levels considered below the minimum requirements of ruminants.
Smoothing, Interpolation, and Gradients from Limited Data1
Authors: Thomas A. W. , Snyder W. M. , Bruce R. R. 
Published: July 2010

AbstractRecent publications have presented a variety of techniques for interpolating and smoothing large masses of agronomic and engineering data. This paper, utilizing the technique of sliding polynomials, demonstrates the development of smooth and continuous curves and gradients from very limited experimental data. Procedures for dealing with data in a transformed time and/or space domain are given. Emphasis is placed on utility of the technique and providing sufficient details through examples to allow ready application.