bluuebunny/crossref_metadata_2025_split huggingface dataset:
Central Appalachian Hill Land Pasture Evaluation Using Cows and Calves. II. Comparison of Animal Days per Hectare Calculations with Statistical Evaluation1
Authors: Burns J. C. , Harvey R. W. , Giesbrecht F. G. , Linnerud A. C. 
Published: July 2010

AbstractIn grazing experiments using variable stocking (put‐and‐take method), animal days ha−1 (from which gain ha−1 is computed) is calculated using the total digestible nutrient (TDN) method. This method has been satisfactorily applied to yearling cattle but not widely used when the tester unit is complicated by two animal types as with the cow‐calf unit. This study uses cow‐calf data from a 6‐year unbalanced grazing trial and compares two methods of computing animal days ha−1 and associated gain ha−1. One method was the TDN procedure consisting of two types of calculations: 1) the standard procedure, using tester animal seasonal mean TDN (SMT) factors, and 2) the calculation of tester animal period mean TDN (PMT) factors. The second method was based on mean tester body live weights computed three ways: 1) converting all weights to a standard weight (453.5 kg) factor (STW); 2) calculating period mean weight (PMW) factors; and 3) calculating seasonal mean weight (SMW) factors. The five animal day calculations were compared for magnitude of year and field variance component and residual error. Relative and absolute values of treatment means were examined. The relative rank of the year and field variance components were generally similar among the five ways of calculating animal days ha−1 and associated gain ha−1. A consistent difference was larger residual error for STW and PMT but smallest for the SMT calculation. The SMT animal days (standard used) and gain ha−1 were highly correlated with STW, PMW, and SMW (r ranged from 0.95**, significant at the 0.01 level of probability to 0.99**) but somewhat lower for PMT (r ranged from 0.82** to 0.88**). Absolute values (both days ha−1 and gain ha−1) from the SMT, PMW, and SMW calculations were very similar, while PMT values were variable and STW values greatly inflated. Results using the SMW and PMW calculations would be very similar to SMT values with little precision lost through increased variance. The use of live weight factors (PMW or SMW) in determining animal days ha−1 is much simpler and requires fewer assumptions than the TDN calcuations.
Yield and Water Relations of Pearl Millet Genotypes under Irrigated and Nonirrigated Conditions1
Authors: Singh Piara , Kanemasu E. T. , Singh Phool 
Published: July 2010

AbstractDrought resistance in pearl millet [(Pennisetum americanum (L.) Leeke] makes it BIR important food crop in arid and semiarid regions, but research is limited on drought resistance and physiological responses to water stress. To study the relationship of pearl millet yield to physiological characteristics, 10 pearl millet genotypes were grown under irrigated and nonirrigated conditions on a silt loam soil (fine‐silty, mixed mesic, Pachic Haplustoll). Leaf diffusion resistance of adaxial (LDRad) and abaxial (LDRab) surfaces, leaf water potential (ΨL, leaf osmotic potential (ΨrL, and stem osmotic potential (Ψrs) of genotypes were recorded in both treatments in the afternoon (1200 to 1700 h) when the crop was water‐stressed. Leaf diffusion resistance (LDR) for a leaf was calculated as LDR = (LDRad × LDRab/(LDRad + LDRab). LDRad, LDRab, LDRab, LDR, ΨL, ΨrL, and Ψrs observed for each genotype were averaged over the stress period and correlated with yields and yield ratios (nonirrigated yield/irrigated yield) of genotypes. Majority of genotypes studies did not differ significantly (P<0.05) in average afternoon LDRab, ΨL, ΨrL, and Ψrs, and water use (WU) in both the treatments except that genotypic differences were significant in average afternoon LDRad and LDR in the nonirrigated treatment. Grain yield was significantly correlated with LDRab in both irrigated (r = −0.90) and nonurigated (r = −0.72) treatments, suggesting that high LDRab of genotypes is associated with low grain yield. Grain yield ratio was significantly correlated with LDRab (r = 0.71) and LDR (r = 0.66) in the irrigated treatment and with ΨrL (r = 0.64) and Ψrs (r = 0.78) in the nonirrigated treatment. Average afternoon ΨL did not correlate with grain yield or grain yield ratio. It is concluded that average afternoon LDRab could be used to rank pearl millet genotypes for their grain yield in both stressed and nonstressed environment.
Tall Fescue Sward Response to Mefluidide and Nitrogen1
Authors: Gerrish J. R. , Dougherty C. T. 
Published: July 2010

AbstractIntroduction of legumes into grass‐dominant pastures often requires destruction or suppression of existing vegetation to minimize competition for light, soil water, and plant nutrients. Mefluidide (N‐[2,4‐dimethyl‐5‐ [[(trifluoromethyl)sulfonyl]amino]phenyl]acetamide) has been used as a growth retardant of cool‐season turf grasses but has not been evaluated as an aid to legume establishment in pasture renovation. Three field experiments conducted at the Kentucky Agric. Exp. Stn., Lexington, Ky. in 1979 and 1980 examined responses of tall fescue (Festuca arundinacea Schreb.) to mefluidide [0.56 kg (a.i.)ha−1] applied in March and/or May under different levels of fertilization on a Maury silt loam (mixed, montmorillinitic, mesic Typic Paleudult). Mefluidide, applied 2 to 4 weeks after spring growth was initiated, reduced tiller weight, leaf weight/tiller, leaf area/tiller, and tiller populations. Mefluidide had no effect on the rate of leaf appearance and increased leaf/stem ratio from 1.38 to 2.34. Fertilizer N increased tiller populations, leaf dry weights, and leaf area/tiller. March applications of mefluidide reduced canopy leaf area index (LAI), but 65 days later LAI values of these plots were 50% higher than LAI's of untreated plots. Mefluidide application in May reduced LAI more severely than March applications and it did not lead to an increase in LAI later in the season. Application of N tended to offset the reduction of LA1 by mefluidide. Annual dry matter yields of tall fescue were reduced 12, 21, and 40% by March, May, and March plus May applications of mefluidide. Mefluidide broadcast in March reduced dry matter yields harvested on 7 May by 54%, but yield obtained at the next harvest was 23% higher than on untreated plots. Mefluidide applied in May reduced dry matter yields at the next harvest by 60% but subsequent yields were similar to those of untreated plots. At the third harvest on 1 August, dry matter yields of plots receiving 80 kg N haΨ1 were 22, 27, and 49% higher when mefluidide was applied on 29 March, 15 May, or on both dates, respectively. While mefluidide suppressed grass growth for 6 to 8 weeks after application, subsequent stimulation of grass growth may increase competition from grasses. Fertilizer N stimulated grass growth even when treated with mefluidide, and would increase competitiveness of established species.
Mineralization of N from Several Sources and Establishment of ‘Penncross’ Creeping Bentgrass on Putting Green Media1
Authors: Mazur A. R. , White C. B. 
Published: July 2010

AbstractThe practice of using little if any soil in putting green mixtures combined with the annual application of large quantities of N fertilizer provides a high potential for loss of N through leaching. Studies were conducted on two putting green media with and without soil [70% (vol.) sand + 20% peat + 10% Cecil sandy loam and 70% sand + 30% peat] to 1) investigate the nitrifier and denitrifier populations; 2) measure the mineralization products of ureaformaldehyde (UF), sulfur‐coated urea (SCU), isobutylidene diurea (IBDU), and urea under both laboratory and field conditions; and 3) determine the leaching losses and rate of ‘Penncross’ creeping bentgrass (Agrostis palustris Huds.) establishment with the respective N source materials. Initially the mixture containing soil had Nitrosomonas and Nitrobacter populations 490 × and 41.5 × higher, respectively, than the mixture without soil. In the field studies no treatment differences were found in nitrifying bacteria populations after 1 month. Little if any urea‐N or NH4+‐N was found in the leachate samples. The influence of percolating water was most evident on leaching losses with SCU and IBDU in the soilless media. The establishment of bentgrass was most rapid with the IBDU treatment in the mixture containing soil with 50% coverage 4 weeks after seeding and 83% coverage after 9 weeks. Even in the soilless mixture establishment rate of bentgrass was greater at 4 weeks with IBDU (22%) than with urea (7%) or UF (8%) but not significantly greater than SCU (18%).
Nitrogen from Legume Cover Crops for No‐Tillage Corn1
Authors: Ebelhar S. A. , Frye W. W. , Blevins R. L. 
Published: July 2010

AbstractMany of the advantages of no‐tillage crop production are due to the presence of a mulch from a cover crop or from crop residue. Legumes can be used to provide the mulch and biologically fixed N to nonlegumes in the system. Field experiments were conducted from 1977 through 1981 to determine the amount of biologically fixed N provided to no‐tillage corn (Zea maysL.) by winter annual legume cover crops of hairy vetch (Vicia villosaRoth), big flower vetch (Vicia grandifloraW. Koch var. Kitailbeliuna), and crimson clover (Trifolium incarnuturnL.). The legumes were compared to a cover of corn residue only and a cover crop of rye (Secale cereuleL.). The soil was a Maury silt loam (Typic Paleudalfs, fine‐silty, mixed, mesic). Fertilizer N treatments of 0, 50, and 100 kg ha−1were combined with each cover treatment. Corn was planted by no‐tillage directly into the cover treatments and the cover crops were killed with herbicides. Hairy vetch produced more dry matter with a higher N percentage which resulted in a higher N concentration in corn plants and substantially more inorganic N (KCI extractable NH+4and NO−3) in the soil than with the other legumes. Big flower vetch and crimson clover provided much less N than hairy vetch. Five‐year average yields of corn grain following hairy vetch cover crop with no N fertilizer were about 2.5 Mg ha−1more than corn yields when following corn residue or rye cover crop. We estimated that hairy vetch supplied biologically fixed N equivalent to approximately 90 to 100 kg ha−1fertilizer N annually to the corn, based on a comparison of grain yields with corn grown in corn residue and rye. In addition to functioning as an effective mulch, certain legume cover crops can provide a substantial portion of the N for no‐tillage corn production, decreasing the amount of N fertilizer needed.
Date of Pod‐Set and Chalcid Fly Infestation in Alfalfa Seed Crops in the Southern Great Plains1
Authors: Ahring R. M. , Moffett J. O. , Morrison R. D. 
Published: July 2010

abstractAlfalfa (Medicago sativa L.) is grown for hay and seed throughout the Southern Plains. Because of cropping practices and the extended reproduction period of the plant, seed pests are a serious problem in the region. Our objectives were to determine the level of alfalfa seed chalcid infestation by the approximate date of pod‐set, to estimate its effect on present crop yields, and to identify alternatives to current cropping practices. Alfalfa seed pods were classified into four color groups according to pod maturity and studied in seasonlocation combinations of one moist subhumid, two dry subhumid, and one semiarid environments. Differences among pod‐color groups in the mean number of chalcid‐damaged seeds were examined using the appropriate LSD with a = 0.05. In each environment, statistically significant differences were found among the four pod‐color groups. Crops harvested from the moist subhumid environment were found to have a severe alfalfa seed chalcid infestation problem throughout the growing season. However, this problem was less severe in the fall. Crops harvested from other environments showed an increasing infestation problem as the cropping season progressed. Harvesting the first, and possibly the second, alfalfa growth of the season for hay and allowing the second or third cut to mature seed (current cropping practice) may present the optimum seed production system for moist subhumid environments. In other environments, using thin stands established in rows and timing the crop to obtain seed in midsummer may reduce the losses currently seen in fall harvests
15N‐Determined Time Course for N2Fixation in Two Cultivars of Field Bean1
Authors: Rennie R. J. , Kemp G. A. 
Published: July 2010

AbstractDinitrogen (N2) fixation was measured for two bean cultivars, ‘Aurora’ and ‘Kentwood’, in a 2‐year field experiment, at four growth stages and two levels (10 and 40 kg ha−1) of fertilizer N1as Ca(NO3)2. Both 15N isotope dilution and modulation parameters were used to determine if nitrogenase activity at these growth stages could explain Aurora's superiority in symbiotic N2fixation. Nodules were actively reducing C2H2at the first trifoliate stage and acetylene‐reducing activity (ARA) increased until anthesis or various stages of pod filling, depending on the cultivar and the year. The addition of fertilizer N at 40 kg ha −1did not alter the pattern of ARA over time although nitrogenase activity was affected. Although nodules were reducing low levels of C2H2at physiological maturity, no activity was observed at harvest maturity. Acetylene‐reducing activity peak activities of 120 and 151 nmol C2H4min−1plant−1for Aurora and 69 and 192 nmol C2H4min−1plant−1for Kentwood in 1981 and 1982, respectively, were similar to values observed for other temperate zone beans. Only a single peak of ARA was observed. The two bean cultivars received similar proportions of their plant N requirements from the atmosphere, averaging 72% in 1981 but only 54% in the cooler year, 1982. Plants apparently had the ability to alter their assimilation of different N sources (air, soil, and fertilizer) to compensate for the lower %Ndfa in the cooler year, 1982. Soil and fertilizer N uptake was particularly important to plant yield in early growth stages until N2 fixation was actively established. Aurora fixed 124 and 114 kg N ha−1(at the 10 kg N ha−1rate) and 124 and 100 kg N ha−1(40 kg N ha−1) in 1981 and 1982, respectively. Kentwood fixed 70 and 97 kg N ha−1(10 kg N ha−1) and 93 and 79 kg N ha−1(40 kg N ha−1) in 1981 and 1982. This superiority of Aurora was due to a longer vegetative phase supporting N2fixation. The ARA severely underestimated N2fixation (as determined by 15N‐isotope dilution) and we believe that N2fixation in beans has been underrated solely because of the inadequacies of ARA. ‘Galt’ barley served as an excellent non‐fixing control plant for 15N isotope dilution to measure N2fixation in these bean cultivars because its pattern of assimilating N from the soils was similar to that of the beans at all growth stages.
Root Growth and Morphology, Nutrient Uptake, and Nutrient Status of Early Growth of Soybeans as Affected by Soil P and K1
Authors: Hallmark W. B. , Barber S. A. 
Published: July 2010

AbstractLittle information is available on the effects of levels of soil P and K on soybean [Glycine max(L.) Merr] root growth and morphology. Soybeans were grown for 9, 16, and 21 days in Raub silt loam soil (fine‐silty, mixed, mesic Aquic Argiudoll) to measure the effect of increasing soil P and K on root growth and morphology and its relation to shoot growth, nutrient status of shoots, and net nutrient influx. Increasing soil P increased shoot weight, root surface area per plant, root surface area per g of root, P, K, Ca, and Mg influx and P, K, Ca, and Mg concentration of shoots. Adding P decreased the root surface area per g of shoot and increased root surface area per g of root. Increasing soil K increased shoot weight (with high P soil), P, K, and Ca influx, and P and K concentration of shoots. Potassium decreased Mg influx and Mg concentration of shoots. Significant positive P ✕ K interactions were found for secondary root radius, P, K, and Mg influx and shoot concentration showing that P and K had their greatest effect when the other nutrient concentration in the soil was high. The effect of P and K on nutrient concentration of shoots followed the same pattern as that for nutrient influx. Since adding P or K changes root surface area per g of shoot, influx of other nutrients changes when they are added. Where influx increases, a sufficient soil level of each nutrient is then needed so that soil supply does not limit influx.
Value of Rice Characteristics in Selection for Resistance to Salinity in an Arid Environment1
Authors: Lehman W. F. , Rutger J. N. , Robinson F. E. , Kaddah M. 
Published: July 2010

AbstractThe reaction of rice (Oryza sativaL.) plants to soil salinity was studied to identify characteristics of possible value in selection and to develop rapid, reliable selection procedures for use in the development of salinity‐resistant rice cultivars. Fourteen characteristics were measured on six cultivars growing in the greenhouse on a mixed hyperthermic Typic Torripsamment‐Rositas very fine sand treated with three levels of salinity for 2 years. Year, cultivar, salinity, and the year ✕ cultivar interaction had highly significant effects on most characters. The significant differences for cultivars ✕ years indicate that observations should be made for 2 or more years. Few characteristics showed significant interactions for the year ✕ salinity and cultivar ✕ salinity interactions. Important exceptions were the reproductive characteristics of percent underdeveloped spikelets and chaff weight (an estimate of blanking). From this it appeared selections could be made to reduce the percentage of underdeveloped spikelets and chaff weight. Characteristics with the highest correlation with seed weight were tillers at seedling stage and panicle length. Straw weight and weight of chaff plus straw had significantly positive correlations with the other vegetative characters, plant height and days to maturity, but significantly negative correlations with the reproductive characters of panicle and seed number and weight. Significant correlations and interactions indicate selections should be made for young plants with many tillers and against vigorous adult plants failing to develop reproductively.
Automated Determination of Chlorides in Soil and Plant Tissue by Sodium Nitrate Extraction1
Authors: Gaines T. P. , Parker M. B. , Gascho G. J. 
Published: July 2010

AbstractAn accurate, precise, and fast automated method for determining Cl in large numbers of soil and plant samples was needed in the confirmation that Cl toxicity was the cause of leaf scorch, a new disorder of soybean [Glycine max(L.) Merr.] grown on Atlantic Coast Flatwoods soils of Georgia. The method described involves the use of 0.1 M NaNO3as an extractant for soil and plant tissue samples with Cl being determined colorimetrically on a Technicon Auto‐Analyzer. Several studies including evaluation of extractants, shaking time, soils of varying texture, tissues of plants, and varying amounts of sample‐ and carbon‐weights were conducted to compare the proposed method with available methods of Cl analysis. Recovery of Cl after KCl was added to soils was 97% using 0.1 M NaNO3. Chloride concentrations in water and 0.1 MHNO3soil extracts could not be accurately determined due to turbidity and acidity interferences. Recovery of Cl from soils by the NaNO3extractant was not aflected by shaking times of 5, 10, and 20 min. Ten days after soils were incubated with KCI the NaNO3extractant was as effective in extracting CI(84%) as Mehlich No. 1 double acid extractant was in extracting K (86%). The NaNO3 extractant was equally effective in extracting Cl from sandy clay, sandy clay loam, loamy sand, and sand soils. Most of the error in the method was in the extraction procedure rather than in the measurement by the Auto‐Analyzer. The NaNO3extraction method compared favorably to the longer ashing method for leaf samples, but ashing was more accurate for seed samples. Fifty samples per hour can be determined by the Auto‐Analyzer.
Effect of Management Practices on Grain Yield, Test Weight, and Lodging of Soft Red Winter Wheat1
Authors: Roth G. W. , Marshall H. G. , Hatley O. E. , Hill R. R. 
Published: July 2010

AbstractLittle yield improvement of soft red winter wheat (Triticum aestivumL. em Thell.) has occurred in Pennsylvania and other northeastern states during the past 30 years while wheat yields have nearly doubled in several European countries. In England and Wales, about 40% of this increase is attributed to improved management. Our objective was to determine the potential yield increases under Pennsylvania conditions from near optimum combinations of seeding rate, row spacing, seeding depth, and N fertilization in the spring. Field experiments were conducted at a total of 15 locations during 1981 and 1982 on either Typic or Ultic Hapludalf soils. The cv. Roland was used, and treatments were seeding rates of 100,168, or 235 kg ha−1, 19 or 38 mm seeding depths, 127 or 178 mm row spacing, and 0, 34, 67, or 100 kg ha−1of N fertilizer topdressed in March at growth stage 3 (Feekes scale). Grain yields ranged from 2642 to 5342 kg ha−1and averaged 4134 kg ha−1. Yields increased in 14 of 15 environments when row spacing was decreased to 127 mm. The average yield increase from using narrow row spacing was about 7.5%. The effect of spring N fertilization was variable but grain yields and test weights were decreased at N levels above 34 kg ha−1. Seeding rate responses also were variable, but averaged over all environments, yields were not increased by using more seed than 168 kg ha−1. The greatest response to seeding rate occurred following late planting. At five of six locations where seeding depth effect was significant, yields were greatest from deep seeding. The best combination of treatments was 168 kg ha−1of seed, 38 mm seeding depth, 127 mm row spacing, and 34 kg ha−1of N. The average yield for this combination was 4630 kg ha−1which is more than double the state average yield.
Allelopathic Effects of Annual Weed Residues on Growth and Nutrient Uptake of Corn and Soybeans1
Authors: Bhowmik P. C. , Doll J. D. 
Published: July 2010

AbstractAnnual weeds have shown allelopathic potential in recent years. Few studies clearly compare effects of weed residues on growth inhibition and nutrient uptake in corn (Zea maysL.) and soybeans [Glycine max(L.) Merr.]. Therefore, the residues (aboveground biomass) of common lambsquarters (Chenopodium albumL.), redroot pigweed (Amaranthus retroflexusL.), common ragweed (Ambrosia artemisifoliaL.), velvetleaf (Abutilon theophrastiMedic.), and yellow foxtail [Setaria glauca(L.) Beauv.] were evaluated for their allelopathic effects on growth and uptake of N, P, and K in corn and soybeans in controlled environments. Weed residues in silica sand produced more inhibitory effects than the mixture of soil (Typic Agriudoll) and sand. The growth inhibition was more (8 to 14%) when the residues were incorporated in all soils than when they were surface applied. All residues except common ragweed reduced corn (6 to 20%) and soybean (2 to 20%) dry matter production. The inhibition or stimulation of N, P, and K uptake in both crops was not consistent and depended on the residue source, residue placement, or soil texture. Addition of supplemental N and P to various residues provided no alleviating effect on crop growth. Addition of P markedly enhanced P uptake without affecting total dry weights of both test species when compared to the controls. Yellow foxtail and common ragweed residues increased K uptake (21 to 48%) in corn but not in soybeans. The weed residues demonstrated an allelopathic inhibition of growth independent of N and P nutrition, and suggest that the inhibitory effects are not related to nutrient uptake.