bluuebunny/crossref_metadata_2025_split huggingface dataset:
Introduction of Effective N2‐Fixing Rhizobia1 Strains into the Soybean Plant by Use of Fungicide Resistance1
Authors: Jones Roger , Giddens Joel 
Published: July 2010

AbstractExperiments were designed to determine if thiram seed treatment reduces populations of competing rhizosphere microorganisms and enhances nodule formation by an effective inoculant strain. Soybeans [Glycine max (L.) Merr.] inoculated in a greenhouse experiment with an effective, fungicide‐resistant mutant of Rhizobium japonicum USDA 110 were shown to produce a greater proportion of nodule isolates that were fungicide resistant. Populations of fungicide resistant rhizobia in the rhizosphere were also found to be higher with fungicide treated than with untreated seed. Rhizosphere total bacterial counts and protozoan populations were lower with treated seed but seed treatment did not significantly affect plant growth. The use of fungicide seed treatment and inoculation with effective (high N2‐fixing) fungicide resistant R. japonicum may offer an improved method of soybean inoculation.
Bermudagrass, Tall Fescue, and Orchardgrass Pasture Combinations with Clover or N Fertilization for Grazing Steers. II. The Species Composition Index and Variability in Forage Growth and Consumption, and Animal Performance1
Authors: Fribourg H. A. , Carlisle R. J. , McLaren J. B. 
Published: July 2010

AbstractForage growth and consumption, animal gain, and beef production were estimated in a steer (Bos sp.) backgrounding experiment concurrently with several environmental, plant, and animal characteristics. This paper describes a technique that combines the dynamic changes in species composition in pastures over time into a Species Composition Index (SCI). This index can then be related to the effects of season, grazing periods, stocking rates, forage crude protein, precipitation, and air temperature on forage growth and consumption, and beef production. The SCI was compared to the traditional classification variable treatments to describe seven differently managed pasture combinations of different forage species. It was superior to treatments in explaining variability and appeared to be a sensitive tool for characterizing dynamically changing pasture compositions. It could be a useful and flexible tool in quantifying species cover in many other situations.
Corn Irrigation Scheduled by Tensiometer and the Lambert Model in the Humid Southeast1
Authors: Hook J. E. , Threadgill E. D. , Lambert J. R. 
Published: July 2010

AbstractA need for a grower acceptable irrigation scheduling technique was brought about by rapid expansion in irrigated land in the Southeast. A modified Jensen‐Haise evapotranspiration formula was adapted by Lambert et al. into an irrigation scheduling and forecasting model for this region. The purpose of this study was to determine if the Lambert model was as effective as tensiometer scheduling in meeting irrigation needs of field corn (Zea mays L.). Corn was grown in seven replicated field experiments and two nonreplicated production scale experiments. Yield and water were compared after irrigation was applied either when soil water pressure in the 150 to 300 mm zone fell below −30 kPa as indicated by tensiometers or when called for by the model. The comparisons were conducted for 3 years on two soils, Tifton loamy sand (fine‐loamy, siliceous, thermic Plinthic Paleudult) and Bonifay sand (loamy, siliceous, thermic, grossarenic Plinthic Paleudult). In five of the comparisons a nonirrigated check was included. The treatment irrigated by the Lambert model yielded 11.1 Mg ha−1 over all seven experiments; the tensiometer irrigated treatment yielded 11.0 Mg ha−1, and the nonirrigated treatment yielded 4.3 Mg ha−1. There were no significant differences between the two irrigated treatments within any year on either soil. The mean yearly water required by the model was 285 mm, compared to 237 mm for the tensiometer. In four of the seven experiments the model called for more water than the tensiometer treatment. Model predicted soil water content was generally greater than measured soil water content for the Bonifay soil but was not significantly different for the Tifton soil. Experience with the Lambert model indicated that it was difficult to determine some of the required model inputs but with correct inputs the model could accurately predict soil water content and corn water requirements.
Planting Method and Plant Population Influence on Soybeans1
Authors: Wright D. L. , Shokes F.M. , Sprenkel R. K. 
Published: July 2010

AbstractNo‐tillage planting of crops usually results in fewer plants per unit of row than the same planting rate with conventional planting. This research was conducted to relate soybean [Glycine max (L.) Merr.] population density under conventional and no‐till plantings to yield and plant growth differences on a Norfolk sandy loam soil (fineloamy, siliceous, thermic Typic Paleudult). ‘Bragg’ soybean were planted in the field with conventional and no‐till planters in 0.76 m wide rows during 1979, 1980, and 1981. Highest yields usually occurred at 20 plants m−1. Yield, plant height, seed weight, and stem diameter differed little in relation to planting method except that seed weight was lower for no‐till plantings in the driest year (1981). Yield and plant height increased and seed weight and stem diameter decreased in relation to population density between 1.5 and 13 plants m−1 row, and then changed gradually to populations of 27 plants m−1 row. Adequate rainfall received during the pod‐fill period of 1979 (August and September) increased yield, plant height, and seed weight more than the planting method in any year.
Battery‐Operated Color Video Camera for Root Observations in Mini‐Rhizotrons1
Authors: Upchurch D. R. , Ritchie J. T. 
Published: July 2010

AbstractA previously described system (Upchurch and Ritchie, 1983) for observing roots in situ has been modified to include a color video camera. The previous system used a black and white video camera and borescope for observations and included several bulky components which caused damage to the crop and made maneuvering difficult. To allow differentiation of new and old roots and improve field performance and picture quality, a color camera and battery‐operated components were added. The new system involved lowering a small video camera and optics system into 51 mm inside diameter (ID) clear, acrylic tubes, which are buried in the soil, and observing the roots intersecting the tubes on a video monitor. All components were battery operated and mounted on a backpack facilitating use of the system in the field. The new system requires approximately 0.3 person h per scan of a 2.4 m mini‐rhizotron. Use of a color camera allowed easier identification of smaller diameter roots and provided an indication of relative root age. As noted in other reports, the technique underestimates root length density near the soil surface. The overall average coefficient of variation was 100%, but when the near surface zone and zone near the rooting front are not considered this was reduced to 30%. Statistically significant differences in rooting between irrigated and water‐stressed maize (Zea mays L.) could be shown for several depths and dates.
Effect of Spray/Planting Intervals and Various Grass Sods on No‐Till Establishment of Alfalfa1
Authors: Eltun Ragnar , Wakefield R. C. , Sullivan W. M. 
Published: July 2010

AbstractConsistently successful legume establishment using sod‐seeding techniques has been difficult to achieve. There is increasing evidence that substances released from herbicide‐treated grass swards have an inhibitory effect on legume germination and seedling growth. Field, greenhouse, and laboratory studies were undertaken to evaluate the effect of spray/planting intervals of 1, 7, 14, and 28 days on the establishment of alfalfa [Medicago sativa] when seeded into sods of orchardgrass [Dactylis glomerata L.] timothy [Phleum pratense L.], and Kentucky bluegrass [Poa pratensis L.], and to examine a possible phytoxic effect of glyphosate [N(phosphonomethyl) glycine] on germination and sod seedling growth of alfalfa. Identical field tests were conducted in the spring of 1981 and 1982 on an Enfield silt loam (coarse‐silty over sandy or sandy skeletal, mixed, mesic Typic Dystrochrept). With few exceptions, the number of alfalfa seedlings, seedling development and alfalfa yields increased as the interval increased between spraying of the sod and seeding. Rate of alfalfa seedling development was reduced in all sods, with timothy being the most inhibitory. Two harvests of alfalfa following seeding confirmed that yields were reduced by killed sod, particularly in orchardgrass and timothy, at early intervals after spraying. There were significant positive correlations between seedling numbers and first harvest yields and between seedling development and first harvest yields of alfalfa. Alfalfa germination was inhibited, seedling development was delayed and total dry weight was reduced when glyphosate‐sprayed grass shoot tissue was soil incorporated in growth chamber seeding tests. However, unsprayed fresh grass tissue was more inhibitory than sprayed grass tissue. Alfalfa germination and hypocotyl and radicle length were reduced by aqueous extracts from glyphosate‐sprayed grass shoot tissue but less so than with extracts from unsprayed herbage. No evidence for a phytotoxic effect of glyphosate could be detected, and it appeared that the inhibition of alfalfa germination and seedling growth was due to allelochemics released from fresh herbage and during the early stages of decomposition.
Fungicide and Temperature Affect Leachate‐Predicted Germination of Cotton1
Authors: Smith C. Wayne , Varvil J. J. 
Published: July 2010

AbstractThe ASA‐610 Automatic Seed Analyzer is used to predict the germination of acid delinted cotton (Gossypium hirsutum L.) seeds, reportedly in 24 h as compared to 7 days by standard methods. The prediction is based on the electrical conductivity of seed leachate, with higher leachate resulting in higher conductivity values and indicating lower germination potential. Because cotton planting seeds usually are treated with fungicides and instruments such as the ASA‐610 may be used to assess planting seed quality without using controlled environmental chambers, this research was initiated. We studied the effects of fungicide treatments and temperature during soaking on ASA‐610‐predicted germination of cotton seeds. Correlations among ASA‐610‐predicted germination and standard (30°C) and cool (18°C) germination tests were determined. Fungicide effects were evaluated by use of aliquots from a single seed lot of ‘Stoneville 213’ treated with 17 different fungicides and/or formulations plus an untreated control and a nine‐entry fungicide test, again applied to aliquots of a single seed lot of Stoneville 213. Samples from 17 commercial planting seed lots were used to study the effects of soaking temperatures and to investigate the correlation between the ASA‐610‐predicted germination and standard germination at 30°C. Of 25 fungicide treatments studied, 20 did not significantly affect ASA‐610‐predicted germination when seeds were soaked for 19 h and partitioned at 55μA/seed. Soaking cotton seeds for 19 h at 18°C resulted in Significantly higher ASA‐610‐predicted germination than soaking at 24 or 30°C. Correlation analysis indicated that the ASA‐610 will not predict accurately the germination of acid‐delinted, commercial planting seeds as defined by standard germination procedures.
An Economic Analysis of N Fertilization of Intermountain Hay Meadows1
Authors: Taylor D. T. , Seamands W. J. , Menkhaus D. J. , Jacobs J. J. , Delaney R. H. 
Published: July 2010

AbstractNitrogen fertilization is an essential management component of intermountain hay meadows. Insufficient studies have been conducted to determine the economic feasibility of the 67 to 90 kg N ha−1 typically applied by the producer. The objectives of this study were to estimate forage yield response functions and to determine the economic optimum levels of N application. Forage response to N fertilization data were collected in intermountain meadows in Wyoming during the period of 1965 to 1980. The three meadow types investigated were native, improved grass and grass‐alfalfa (Medicago sativa L.) mixtures with 29, 10, and 16 field trials, respectively. Application rates for the N fertilizers ranged from 0 to 180 kg ha−1. The yield response equations were used to determine the economic optimum level of N application for three alternative prices for hay and N fertilizer. The mean economic optimum level of N application for the three price levels was 149,161, and 101 kg N ha−1 on native, improved grass, and grass‐alfalfa meadows, respectively. The improved grass species demonstrated a greater response to the higher levels of N than the other two meadow types. This study indicates that average producers are applying N to intermountain hay meadows at average rates considerably below the economic optimum. Assuming a net hay price of $55 Mg−1 and an N price of $61.60 100−1 kg, the returns ha−1 over fertilizer and harvest costs could be increased $15, $19, and $1 ha−1 for native, improved grass, and grass‐alfalfa meadows, respectively, if the economic optimum N rates were applied as compared to the typical level of 90 kg ha−1.
Environmental Interactions among Reed Canarygrass Genotypes for Nutritive Value, Height, and Disease Severity1
Authors: Zeiders K. E. , Sherwood R. T. 
Published: July 2010

AbstractThe objective of this study was to determine whether genotypes of reed canarygrass (Phalaris arundinacea L.) that were superior for in vitro digestible dry matter (IVDDM), crude protein content (CP), plant height, and resistance to tawny blotch [Stagonospora foliicola (Bres.) Bubak] without irrigation were also superior under irrigation with municipal wastewater effluent involving two and three cuttings per year. Twenty‐five genotypes were established as spaced plantings in central Pennsylvania on a Hagerstown silt loam soil (fine, mixed, mesic Typic Hapludalf). Main blocks were not irrigated or were sprinkler‐irrigated with municipal wastewater effluent one or two times weekly from kite May through mid‐September. Subblocks in four replications were harvested two or three times per year. Plant height was measured at all harvests, and IVDDM and CP were determined for the first and third harvests. Tawny blotch severity was rated at the second and third harvests. Significant differences as determined by orthogonal contrasts were observed among the 25 genotypes for each trait. The number of genotypes involved in interactions with each environmental variable were: irrigation 16, cutting frequency 13, harvest 24, and year 18. The number of genotypes that contributed to interactions for each trait were: IVDDM 18, CP 16, height 24, and tawny blotch 12. These results indicated wide differences in environmental stability of genotypes. No genotype was superior for all traits over all environments. There were significant phenotypic correlations between irrigated and nonirrigated clonal means for IVDDM and CP in spring but not in fall harvests. In vitro digestible dry matter in fall never correlated with spring IVDDM, but fall CP often correlated with spring CP. In vitro digestible dry matter was correlated with CP in spring but not in fall. Plant height in any environment correlated with height in any other environment. Tawny blotch rating appeared to be independent of IVDDM, CP, and height. Some genotypes that performed well without irrigation also performed well under irrigation.
Comparison of Crop Phenology Models1
Authors: French Vikki , Hodges Tom 
Published: July 2010

AbstractThree winter wheat (Triticum aestivum L.) phenology models (CERES‐wheat, TAMW, Robertson) were compared for accuracy in estimating jointing, heading, dough, and ripe stage dates for winter wheat at the Crop Reporting District (CRD) level in Kansas. The models' estimates of stage dates were compared to weekly USDA Statistical Reporting Service stage observations for even years during 1952 to 1980. Odd years were reserved for calibration of models. The CERES‐wheat model estimates were consistently more accurate for all stages.
Application Consistency of Operator‐Propelled Field Plot Spray Methods1
Authors: Krall J. M. , Packer D. S. , Davison J. C. , Book D. N. 
Published: July 2010

AbstractOperator‐propelled spray methods were compared for consistency of application under field‐plot conditions. A bicycle sprayer, backpack sprayer, backpack sprayer with a metronome set for normal pace, and the backpack sprayer with a metronome set for a modified pace were tested over two terrains by three operators. Coefficient of variation of application output revealed that an operator can apply pesticides using a backpack sprayer and a metronome with the same application consistency as a speedometer‐aided bicycle sprayer. When the metronome is used to modify pace, ground speed may have greater variance, but should be more consistent than backpack application without a metronome.
Enhancing Germination of Indian Ricegrass Seeds with Sulfuric Acid1
Authors: Young James A. , Evans Raymond A. , Easi Debra A. 
Published: July 2010

AbstractIndian ricegrass [Oryzopsis hymenoides (R. & S.) Ricker] is the dominant forage species on millions of hectares of rangeland in the western United States. Revegetation of degraded rangeland by seeding Indian ricegrass has been generally unsuccessful because of low seed germination. Our purpose was to evaluate the influence of acid seed scarification on germination of Indian ricegrass seeds. Seeds of ‘Paloma’ and ‘NezPar’ Indian ricegrass were scarified in sulfuric acid (H2SO4) from 0 through 45 min at 5‐min intervals. Without scarification, germination of the seeds of these two cultivars was less than 10%. Seedlots from 1 to 11 years old were treated. Germination data were used to develop regression equations for the relationship between duration of acid seed scarification and germination for each cultivar. Seeds of Paloma Indian ricegrass required 25 to 35 min of scarification, whereas seeds of NezPar required 15 to 25 min scarification. The relative composition and morphological forms of the seed may explain the difference in duration of required scarification. The scarified seeds were incubated at 55 constant and alternating temperatures to obtain data with which to construct quadratic response surfaces for temperature‐germination profiles. Even with scarification, the seeds of the two cultivars produced mean germination for the profiles of only 9 to 31%. The dormancy of Indian ricegrass seeds is controlled by complex interacting factors. Acid scarification is a very imprecise tool for enhancing the germination of dormant seeds of Indian ricegrass.
Endomycorrhizal Fungi in Breeder Wheats and Triticale Cultivars Field‐Grown on Fertile Soil1
Authors: Young J. L. , Davis E. A. , Rose S. L. 
Published: July 2010

AbstractA survey of four cereal research fields growing various commercial and breeder wheat (Triticum aestivum L.), and triticale (X Triticosecale), cultivars revealed the presence of several endomycorrhizal fungi in soils with elevated levels of available P. Extractable (Bray) P levels of sampled fields ranged from 73 to 119 mg kg−1–this in an area where unirrigated wheat yields may exceed 5500 kg ha−1 (> 100 bu acre−1) and the Extension Service “Fertilizer Guide” calls for no P fertilizer additions on grains when soil test values for P are >30 mg kg−l. Cortex colonizations among the >60 breeder and commercial wheat cultivars (sampled just preharvest) were variable and relatively low (range <2 to >18%) partly due to declining root tissues at this stage. Atrophied fine feeder roots and degraded cortical areas were common, yet, in many cases, moderately abundant external hyphae remained adherent to weakened root segments, despite rigors of washing, clearing, and staining. Triticale roots, among the 12 cultivars sampled, were also colonized but at lower percentages (range, 1 to 13%). Vesicular‐arbuscular mycorrhizal (VAM) fungi isolated from the well‐fertilized fields included several Glomus spp., Acaulospora laevis, and an occasional Sclerocystis sporocarp. The A. laevis and a Glomus mosseae type were by far the most common endophytes in terms of spores recovered. Of these isolates tolerating the plentiful soil P status, the Gl. mosseae‐type spores predominated at pH's 5.7 and 6.3. Acaulospora laevis spores greatly dominated in the strongly acid field (pH 4.3 to 4.8) although the Gl. mosseae began to reestablish/recompete where liming nudged the soil back to ~pH 5.7. The abundance of A. laevis spores found with the monocotyledonous wheats contrasts with a published suggestion that Acaulospora species develop in association with dicot hosts. One hopes that bioassay of such higher‐fertility tolerant species will lead eventially to discovery of effective VAM fungal isolates that can still benefit crops despite high‐input fertilizer, pesticide, or water management practices.
Effect of N, P, and S Fertilizers on Alfalfa Grown on Three Soil Types in Northeastern Saskatchewan. II. Nitrogen, P, and S Uptake and Concentration in Herbage1
Authors: Nuttall W. F. 
Published: July 2010

AbstractBecause N, P, and S fertilizers may be important in the production of high quality alfalfa (Medicago media Pers.) herbage in northern Saskatchewan, concentration of these elements in herbage was measured from experiments with N, P, and S fertilizers applied to alfalfa plots over an extended time period. Nitrogen rates at 10, 45, and 67 kg N ha−1 were applied in combination with 0, 22, and 45 kg S ha−1. Twenty kilograms P ha−1 was applied with these treatments. Other treatments were 10, 0, 0; 10, 10, 0; 22, 0, 26; and 0, 0, 0 (Control); N, P, S ha−1 rates, respectively. In general, first cut alfalfa herbage was lower in protein‐N than the second cut with the exception of 1 year. The lowest N concentration per cut was 33.4 g kg−1 averaged over the life of the stand at the Whitefox site (Wf fsl, Whitefox fine sandy loam, Typic Cryoboralf). The highest N concentration in herbage per cut was 39.7 g kg−1 at the Waitville site (Wv 1, Waitville loam, Typic Cryoboralf). Only at the Wv 1 site, and only with S fertilizer, was N concentration consistently increased every year (after establishment year). The percentage of applied N recovered in the alfalfa ranged from 48 to 95%. Approximately 14 kg S ha−1 per year (two cuts) was removed by herbage when fertilized at 22 kg S ha−1 at the Wv 1 site. At a fertilizer rate of 45 kg S ha−1, uptake of P per year (two cuts) was approximately 19.0 kg P ha−1. The lowest yield of N was 78 kg N ha−1 per cut at the Wv 1 site averaged over the life of the stand. The highest uptake was 128 kg N ha−1 per cut at the Melfort soil site (M sic, Melfort silty clay, Typic Cryoboroll). A range of 14:1 to 21:1 of the N to S ratio in herbage was the limit indicated for a S deficiency in the alfalfa crop. Plant testing could be used in conjunction with the soil test for S in making fertilizer recommendations.