bluuebunny/crossref_metadata_2025_split huggingface dataset:
Yield and Fiber Quality of Cotton Following Applicatioin of 2‐Chloroethyl Phosphonic Acid1
Authors: Smith C. Wayne , Cothren J. T. , Varvil J. J. 
Published: July 2010

AbstractThe indeterminate growth habit of cotton (Gossypium hirsutum L.) forces producers to harvest more than once or to postpone harvest for several weeks. Ethephon (2‐chloroethyl phosphonic acid) causes immature bolls to open, resulting in a greater percent of the crop harvested at first harvest or in once‐over harvest. The objectives of this study were to determine the effects of ethephon on seedcotton yields and fiber quality relative to the physiological stage of maturity at treatment with ethephon. ‘Stoneville 213’ and ‘CAMD‐E’ were planted on three dates in 1980 and Stoneville 213 on four dates in 1981 in Calloway silt loam, a Glossaquic Fragiudalf. Ethephon was applied at 1.12 kg ai. ha−1 and compared with no ethephon treatment in 1980 when plants ranged from 19 to 62% opened bolls. Stoneville 213 ranged from 12 to 72% opened when treated in 1981. The statistical design was a split‐block, split‐plot of a randomized complete block with four replications. Ethephon significantly reduced seed cotton yield when applied to cotton with 48 to 62% opened bolls in 1980 but not when applied to cotton averaging 22% opened. In 1981, no consistent effects of ethephon on seed cotton yields were detected. Over years, ethephon applied to cotton with 12 to 25% opened bolls did not reduce seed cotton yields relative to application to cotton with 48 to 72% opened bolls. No consistent detrimental effects on fiber quality were detected for fiber from first harvest or from once over harvest.
Normal‐12 and Brown Midrib‐12 Sorghum. I. Variations in Tissue Digestibility1
Authors: Akin D. E. , Hanna W. W. , Rigsby L. L. 
Published: July 2010

AbstractReduced lignin contents in brown midrib (bmr) mutants of sorghum (Sorghum bicolor L. Moench.) are reported to improve the digestibility of this forage. The objective of this study was to evaluate microscopically leaf blades of normal‐(N) 12 and bmr‐12 sorghum for variations in anatomy, histological reactions of tissues for lignin, and specific tissue digestion to elucidate the contribution of the bmr‐ 12 mutation to improved forage quality. No differences in anatomy or histology of lignified tissues was observed between N‐12 and bmr‐ 12 plants. Midribs of N and bmr plants, examined by scanning electron microscopy after a 48 to 72 h incubation with rumen fluid were partially degraded, with a tendency for parenchyma in bmr leaf blades to be more degraded than that in N leaf blades. Other tissues, i.e., epidermis and xylem, were not degraded in either plant type. In the non‐midrib portion of blades, the parenchyma bundle sheaths and adaxial sclerenchyma areas were degraded to a greater extent in bmr plants by mixed rumen microorganisms and by a pure culture of the cell wall‐degrading rumen bacterium Ruminococcus flavefaciens FD‐1. Epidermis and mesophyll at times more rapidly degraded in bmr plants. In leaf sheaths, no marked differences in digestion between N and bmr plants were found with parenchyma totally degraded in both plant types. Xylem and other tissues normally highly resistant to microbial degradation were not degraded in plant parts of either N or bmr types. The bmr‐12 mutation did not result in changes in leaf blade anatomy or histological reactions for lignin and did not result in susceptibility to microbial degradation of the most resistant tissues. The bmr‐12 mutation did allow an improved microbial degradation of marginally digestible tissue, i.e., those tissues usually only poorly degraded.
Phenology of Dent Corn and Popcorn. III. Improved Crop Development Models1
Authors: Stevens E. J. , Stevens S. J. , Flowerday A. D. , Gardner C. O. , Eskridge K. M. 
Published: July 2010

AbstractSimple temperature‐dependent phenological regression models have been used for many years to predict seasonal development for dent corn (Zea mays L.) and sweet corn. However, only limited data are available for popcorn. More complex models have taken into account the effects of photoperiod but seldom planting date variation with respect to additional environmental variables. A recently established network of automated climate stations, reporting daily to centralized locations in the states of Nebraska, Kansas, Colorado, and South Dakota, has facilitated modeling corn phenology using hourly rather than daily data or long‐term temperature normals. Soil temperature data is also recorded by these weather stations. An interactive agroclimatology program and service (AGNET) offered by the University of Nebraska, Lincoln (UNL), utilizes some of these data as daily thermal units accumulated from the time of planting. The objectives of this research were to evaluate, and where necessary, modify models used by AGNET after studying the influence of (i) using hourly thermal units accumulated from 50% seedling emergence, (ii) photoperiod effects associated with variations in planting date and seedling emergence, and (iii) using a modified universal growth staging procedure and growth curve analysis. A 2‐yr phenology study incorporating three planting dates, one dent corn hybrid (B73 × Mo17), and three popcorn hybrids (P410, P609, and Iopop 12) was conducted in eastern Nebraska during 1982 and 1983. Statistically significant differences were detected among hybrids, among planting dates, and between years for regression coefficients derived from thermal and photoperiod/thermal regression models. Heat sums calculated over a range of temperatures between 5 and 28°C corrected for heat stress tended to be more consistent over the years than those calculated using a range of 10 to 30°C. The maturity rating of some corn hybrids was not constant across all planting dates modeled in terms of thermal units accumulated prior to the crop reaching a particular stage of phenological development. Iopop 12 matured proportionately earlier as planting date was delayed (i.e., fewer thermal units were accumulated prior to physiological maturity). As planting date was delayed the maturity rating of P41O remained unchanged while P609 matured later. The dent corn hybrid B73 × Mol7 first became earlier maturing then later maturing as the date of planting was delayed. A need to account for daylength at crop emergence as well as additional environmental variables associated with changing planting dates and the maturity rating of cultivars was demonstrated.
Evaluating the Genetic for Germination Salt Tolerance in Alfalfa Using a Sodium‐Chloride Gradient1
Authors: Robinson D. L. , Dobrenz A. K. , Smith S. E. 
Published: July 2010

AbstractProgress made in breeding for salt tolerance at germination may be difficult to evaluate when only limited numbers of salinity levels are used for germplasm comparison. Patterns of response to salt stress may be better distinguished when seed is germinated at numerous osmotic potentials. A gradient of osmotic potentials can be easily created by making a series of small dilutions of a concentrated salt solution. Using this technique, alfalfa (Medicago sativa L.) seed from the cultivar Mesa‐Sirsa and a Cycle 7 syn‐1 experimental developed from Mesa‐Sirsa were planted in 37 concentrations of NaCl ranging from 0 to −2.87 MPa. Germination responses across the gradient were sigmoid shaped for both germplasm sources. Natural logarithmic transformations of the data revealed relatively similar and constant germination rates for the two populations at osmotic potentials between 0 and −0.75 MPa. Below these osmotic potentials, percent germination declined abruptly in Mesa‐Sirsa while in Cycle 7 syn‐1, a stable germination rate was maintained until the salt level reached −1.76 MPa, a threshold concentration more than 2.3 times that of Mesa‐Sirsa. At salinities greater than these threshold values, the two populations exhibited similar rates of decline in seed germination. Cycle 7 syn‐1 seed germinated more than twice as fast as Mesa‐Sirsa at −1.90 MPa. Selection for salt tolerance has both extended the germination range of alfalfa by 1 MPa and decreased the time required for seed to reach peak germination speed by 5 days. An osmotic gradient provides an excellent method for evaluating germplasm performance in a salt tolerance breeding program.
Alfalfa Establishment and Production on Soils with Different Drainage Characteristics1
Authors: Jones J. H. , Olsen F. J. 
Published: July 2010

AbstractAlfalfa (Medicago sativa L.) production is reduced by poor drainage, moisture stress, and impervious soil horizons. This study was conducted to evaluate the establishment and production of alfalfa in relation to drainage characteristics. Four alfalfa cultivars, Cody, Spredor, Weevlchek, and WL‐307, were seeded on three soil series, a deep well‐drained Alford (fine‐silty, mixed, mesic Typic Hapludalf), a moderately well‐drained Hosmer (fine‐silty, mixed, mesic Typic Fragiudalf), and a nearly level, poorly drained Weir (fine, montmorillonitic, mesic Typic Ochraqualf). Soil moisture levels for the 0‐ to 0.90‐m depth for the three soil series varied according to rainfall and soil water recharge. Soil moisture depletion for the Alford series at the 0.90‐ to 1.80‐m depth was great due mostly to root proliferation. However, soil moisture depletion for Hosmer and Weir series at the 0.90‐ to 1.80‐m depth was much less than the Alford series, indicating little root proliferation into the fragipan and claypan at this depth. The highest dry matter yields were obtained on the well‐drained Alford site, whereas the lowest yields were generally obtained on the poorly drained Weir site. Alfalfa stands persisted for 7 yr on the well‐drained Alford series and the moderately well‐drained Hosmer series and for 5 yr on the poorly drained Weir series. The selection of a well‐drained soil site is essential for best alfalfa establishment, persistence, and high production. However, moderately well‐drained soils may be used for alfalfa production when well‐drained soils are unavailable.
Conservation Tillage and Irrigation Effects on Corn Root Development1
Authors: Newell R. L. , Wilhelm W. W. 
Published: July 2010

AbstractThe effects of conservation‐tillage practices on the root environment of corn (Zea mays L.) may differ with varying amounts of irrigation. Dryland, 50% irrigation, and 100% irrigation treatments were applied in combination with disc, no‐tillage, and a postemergence chisel treatment designed to allow rapid infiltration of irrigation water. The study was conducted during the 1980 growing season at the Nebraska Agricultural Experiment Station near Mead, NE, on a Sharpsburg silty clay loam (fine, montmorillonitic, mesic Typic Argiudolls). Root samples were taken to 1.50 m in 0.15‐m increments. Sampling was done at 60 (V8), 77 (V14), and 90 (R2) days after planting. Root length per soil volume as a function of depth from the soil surface was characterized using hybrid B73 × Mo17. Root length exhibited linear and often quadratic distribution over sampling depths at all sampling dates. The 100% irrigation treatment exhibited greatest total profile (0‐ to 1.5‐m) and surface (0‐ to 0.15‐m) root length at R2. Dryland and 50% irrigation treatments were associated with relatively greater root length proliferation deep in the soil profile. Differences in root length distribution were not as pronounced at stages V8 and V14. Chisel and no‐tillage treatments, with crop residues at the soil surface, resulted in greater surface (0‐ to 0.15‐m) and total profile root length than discing. Corn roots tended to explore the lower profile to a greater extent under water stress conditions. This phenomenon, in conjunction with soil water conservation by no‐tillage methods, may allow irrigators to increase water‐use efficiency by better use of stored soil moisture.
Quality Analysis of Summer‐Annual Forages. III. Prediction of Wet Silage In Vitro Dry Matter Disappearance from Chemical Constituents1
Authors: Fisher D. S. , Burns J. C. 
Published: July 2010

AbstractSamples for the determination of silage quality are generally dried prior to analysis even though some silage constituents are lost during drying. The objectives of this study were to examine the prediction of wet silage in vitro dry matter disappearance (IVDMD) from analysis of dried samples using both oven‐dried and freeze‐dried fodder and silage. Frozen, wet silage was ground to pass a 1‐mm screen using liquid N as a cryostat. The IVDMD of ground, frozen silage (GFS) was found to be most closely related to the IVDMD of freeze‐dried fodder (FD), with GFS IVDMD = 24.7 + 0.99 (FD IVDMD) and r2 = 0.76**. Weaker relationships were found with freeze‐dried silage (FDS) (r2=0.46**), oven‐dried silage (ODS) (r2=0.35**), and oven‐dried fodder (OD) (r2=0.34**). The relationships between the IVDMD of GFS and fiber fractions of neutral detergent fiber (NDF), acid detergent fiber (ADF), permanganate lignin, apparent cellulose, apparent hemicellulose (NDF—ADF), and the ADF/lignin ratio as independent variables were examined using stepwise regression. Freeze‐dried fodder lignin (r2=0.44) and OD ADF (r2=0.37) were the two single fractions most closely related to wet silage IVDMD. Correlations from the Van Soest fractions alone in single variable regressions were not improved when using stepwise multiple regression analysis.
Precision and Bias of Various Soybean Dry Matter Sampling Techniques1
Authors: Hunt P. G. , Burnham K. P. , Matheny T. A. 
Published: July 2010

AbstractA balance between sample sizes sufficient to detect real differences and resources necessary to obtain and process samples is a continual problem for scientists. In the first year, this study assessed the precision and bias associated With three subplot sampling techniques used for estimating soybean [Glycine max (L.) Merr.] shoot dry matter production: (a) random 1 m of row, (b) random 0.3 m of row, and (c) four randomly selected plants. The experimental design was a split‐split plot. Three cultivars (Braxton, Coker 338, and Davis) were the whole plots, and three sampling date plots were the subplots. Measurement of the total plant dry matter within the subplots as well as the dry weight obtained by three sampling methods constituted the four split‐split plots. When dry matter data were averaged over time and cultivar, the coefficients of variation (CV) for the sampling techniques (a), (b), and (c) were 0.187, 0.417, and 0.386, respectively. The CV was 0.088 when the 20‐m2 subplot (27 m of row) was measured. The 1‐m technique did not significantly overestimate dry matter production relative to the entire subplot measure, but the 0.3‐m and four‐plant (4‐P) techniques significantly overestimated dry matter production. Cultivar, date of sampling, and cultivar ✕ date‐of‐sampling interaction effects in the analysis of variance were significant at P ≤ 0.05 only when data from the entire subplot or 1‐m sampling technique were used. A second study in 1985 also showed that the 0.3‐m and 4‐P sample techniques were poor for both precision and accuracy. This second study also compared the precision and bias of 1‐ and 2‐m samplings as well as the precision and bias associated with different technicians. The 1‐ and 2‐m techniques gave equally unbiased results, but the 1‐m technique did not give equally good precision (CV). Comparison of techniques was not significantly affected by technicians. We concluded that adequate accuracy and precision were obtained by use of the 1‐m or 2‐m sampling technique, but not by the 0.3‐m or 4‐P techniques.
Modeling Long‐Term Crop Response to Fertilizer Phosphorus. I. The Model1
Authors: Wolf J. , de Wit C. T. , Janssen B. H. , Lathwell D. J. 
Published: July 2010

AbstractPrediction of long‐term crop response to fertilizer P should result in more efficient use of this resource. To achieve this, a simple model designed to calculate the long‐term recovery of fertilizer P was developed and is presented here. In the model, both a labile and a stable P pool are distinguished. With time intervals of 1 yr, the model calculates the P transfers between the pools, the uptake of P by the crop, and the resulting pool sizes. Most input data required to operate the model can be obtained from ordinary one‐season fertilizer P trials. Input data, model parameters, and initial pools can be derived from field trials, and the model can be used to calculate long‐term recovery of fertilizer P. The sensitivity of the model is demonstrated by changing parameter values. The model can also be used to establish long‐term fertilizer recommendations for a certain target P uptake. Required rates of fertilizer P are calculated for different soils, fertilizer types, target uptakes, and periods of time.
Seeding Rates for Establishing Big Bluestem and Switchgrass with Preemergence Atrazine Applications1
Authors: Vogel Kenneth P. 
Published: July 2010

AbstractThe purpose of this study was to determine seeding rates for establishing switchgrass (Panicum virgatum L.) and debearded big bluestem (Andropogon gerardii Vitman) when atrazine |6‐chloro‐N‐ethyl‐ N'‐(1‐methylethyl)‐1,3,5‐triazine‐2,4‐diamine] is used as a preemergence herbicide. The high seed cost of these grasses makes it uneconomical to use higher seeding rates than necessary. The study was conducted on four eastern Nebraska sites during the period 1981 to 1985. The experimental design was a randomized complete block with six replications. Treatments were grasses (big bluestem and switchgrass) and seeding rates [107, 215, 325, and 430 pure live seeds (PLS) m−2] in a factorial arrangement. Plots were seeded in late spring with a plot seeder with double disk openers on a clean, firm seedbed, and broadcast sprayed with 2.2 or 3.0 kg ha−1 atrazine the day after seeding. Stands and forage yields were measured the first (Year 1) and second year (Year 2) following establishment. The 107 PLS m−2 seeding rate resulted in thinner, but still acceptable, stands (10–20 plants m−2) than the higher seeding rates in Year 1 and at two of the sites in Year 2. The stands from the higher rates, in general, did not differ within a site and were good to excellent ( >20 plants m−2). The lowest seeding rate produced lower forage yields than the other rates in Year 1, but these differences were significant at only one site. There were no differences for Year 1 yield for the other rates or for Year 2 yields for all rates.
Location, Year, Maturity, and Alfalfa Competition Effects on Mineral Element Concentrations in Smooth Bromegrass1
Authors: Casler M. D. , Collins Michael , Reich J. M. 
Published: July 2010

AbstractMany environmental factors influence the level of herbage mineral elements and ratios, often to an extent potentially affecting ruminant performance. This study was conducted to estimate main effects and interaction effects of locations, years, stand types (pure stands vs. binary mixtures with alfalfa, Medicago sativa L.), and growth stages on the concentration of 11 mineral elements and three elemental ratios of smooth bromegrass (Bromus inermis Leyss.) herbage. Nine families of smooth bromegrass were grown in 2.7‐m2 plots, with and without alfalfa, at Hancock, WI (mixed, mesic, Typic Udipsamment soil) and Lancaster, WI (fine‐silty, mixed, mesic Typic Hapludalf soil). Plots were sampled for seven weekly intervals in 1982 and 1983, from the 17‐ to 22‐cm height stage to 7 days post‐anthesis. Stand types were whole‐plots in four randomized complete blocks; herbage samples were pairwise‐composited to provide two replicates. Samples were analyzed for P, K, Ca, Mg, S, Zn, Mn, Fe, and Cu by plasma emission spectroscopy and for N by micro‐Kjeldahl. Location, year, or stand type effects were significant for every element or ratio [Ca/P, N/S, and K/(Ca+Mg)]. The direction and magnitude of these effects varied considerably among elements and ratios. All three environmental effects (locations, years, and stand types) interacted strongly for most elements and ratios. All elements and ratios decreased with advancing maturity, except Ca/P, which increased. Relative changes over a 40‐day early May to mid‐June period were greatest for N (−97% of the overall mean) and smallest for Mn (−8% of the overall mean). Rate of change due to maturation for most elements tended to follow the pattern: 1982 > 1983, Hancock > Lancaster, and pure stands > mixed stands. For the diet of a moderately producing dairy cow (Bos spp.), smooth bromegrass herbage was severely deficient in P, Ca, Mg, S, Zn, Fe, and Cu at advanced stages of maturity, and excessive in K/(Ca+Mg) at all maturity stages. Although some of these deficiencies could be corrected by breeding, most would be more effectively corrected by fertilization or supplementation
Effects of Alfalfa Proportions and Clipping Frequencies on Timothy‐Alfalfa Mixtures. I. Competition and Yield Advantages1
Authors: Ta T. C. , Faris M. A. 
Published: July 2010

AbstractGrowing legumes in mixture with grasses has been of great interest to improve herbage production. The productivity of timothy‐ (Phleum pratense L.) alfalfa (Medicago sativa L.) mixtures at two plant density proportions (1:1 and 1:2) was compared with their component species grown in pure stands in the field (Manotick sandy loam soil, Typic Dystrochrett). In 1984 and 1985, the plots were harvested at the early, mid‐, and late‐bloom stages of alfalfa, which resulted in five, four, and three cuts per year, respectively. Results indicated that mix‐cropping timothy with alfalfa significantly increased both herbage and N concentration when compared to timothy grown in a pure stand. The magnitude of this increase correlated positively with the alfalfa proportion in the mixture. Although timothy had a dominant competitive ability over alfalfa in the first year (competitive ratio > 1), the situation was reversed in the second year at the higher alfalfa proportion. The land equivalent ratio of mixtures was always > 1 at different cuts under three harvest systems in both years, indicating the advantage of a timothy‐alfalfa mixture over a timothy pure stand, for herbage production. There was an indication that harvesting mixtures when alfalfa reached mid‐bloom (four cuts) increased total herbage and N concentration in both species when compared to harvesting at early (five cuts) or late (three cuts) bloom. Growing timothy in mixture at a high plant density‐proportion of alfalfa and harvesting when alfalfa reaches mid‐bloom stage provides high herbage and N yields of pasture.
Maleic Hydrazide Effects on Soybean Reproductive Development and Yield1
Authors: Helsel Zane R. , Ratcliff E. , Rudolph W. 
Published: July 2010

AbstractDrift or misapplication of maleic hydrazide (MH) to tobacco (Nicotiana tabacum L.) sometimes effects neighboring soybean [Glycine max (L.) Merr.] fields. Our objective was to determine the effects of various rates and timings of MH application on soybean reproductive development and yield. Applications of 0.34 to 3.4 kg a.i. ha−1 were applied to soybean during the R3 to R6 growth stages. Significant (P<0.05) yield reductions from 30 to 100% occured when even low rates of MH were applied to soybean at growth stages R3 and R4. Yield losses occurred primarily as a result of decreased numbers of pods per plant. Injured soybean plants remained green until killing frosts. Plants treated with MH at the R5 and R6 stages experienced no yield loss and matured normally. Planting shorter‐season soybean cultivars early could result in soybean being past the sensitive stages when MH is applied, resulting in little or no injury if misapplication or drift occurs.