bluuebunny/crossref_metadata_2025_split huggingface dataset:
Seasonal Changes in Reflectance of Two Wheat Cultivars1
Authors: Leamer R. W. , Noriega J. R. , Wiegand C. L. 
Published: July 2010

AbstractAccurate crop identification from remote sensing signals is dependent on a knowledge of differences in characteristics of reflectance from various crop canopies. The objective of the present work was to follow changes in the reflectance of two dissimilar wheat [Triticum aestivum (L.)] cultivars through a growing season to determine which reflectance characteristics were suitable for use in the analysis and interpretation of spectral reflectance curves. Reflectance over the wavelength interval of 0.45 to 2.50 μm was measured with a ground‐based spectroradiometer on nine cloud‐free days between planting and maturity of wheat planted on Hidalgo sandy clay loam (Typic Calculstols) soil. Seeding rate affected the rate of ground cover, but not the spectral reflectance of either a winter or a spring wheat once about 25% of the area was covered by vegetation. All reflectance curves had the characteristic shape for vegetated surfaces by 4 weeks after emergence. The proportion of the ground covered by plants was more important than development stages of the plants in determining spectral responses, except at the end of the season when the plants senesced and lost pigmentation. Through the season soil was much less reflective than green vegetation at 0.75, 0.90, and 1.10 μm and much more reflective at 1.65 and 2.20 μm, making these wavelengths valuable for distinguishing vegetation from soil background and for assessing vegetation cover or density.
Bayes Least Significant Difference: A Review and Comparison1
Authors: Smith C. Wayne 
Published: July 2010

AbstractThe Bayesian approach to mean separation overcomes the objections to previous least significant difference (LSD) procedures by having a direct dependence upon the calculated F value. This procedure has the power of a comparisonwise approach when F is moderate to large in size and is conservative at F values less than about 3.0. The Bayes LSD has the same form as the Fisher LSD, i.e., LSD = sdt, where the Bayes t is not to be confused with Student's t. In the example cited, the Bayes LSD was found to be a more powerful test than the Fisher LSD, Tukey's honest significant difference (HSD), or the Duncan new multiple range (DMR) when F = 45.36, moderate in size and comparative to the Fisher LSD and the DMR when F = 4.43, and conservative and comparable to Tukey's HSD when F = 1.4. The use of BLSD rather than LSD to designate the Bayes Least Significant Difference procedure is suggested.
Response of Soybeans to Commercial Soil‐Applied Inoculants1
Authors: Nelson D. W. , Swearingin M. L. , Beckham L. S. 
Published: July 2010

AbstractRecent development of soil‐applied inoculants, which have been advertised in midwestern states as increasing yields by an average of 10%, has stimulated a great deal of interest among soybean (Glycine max (L.) Merr.) producers. Field studies with two soybean varieties were conducted over 2 years (three different cultivars were used), to evaluate crop response to application of commercial soil‐applied Rhizobium japonicum inoculants. Conventional seed‐applied inoculants were also studied for comparison of effectiveness. Plots were established on a highly productive silty clay loam soil which had not been cropped to soybeans for more than 15 years (the native population of rhizobia was assumed to be low). Grain yields, nodulation, and leaf and grain composition were measured. Inoculation of soil or seeds with commercial inocultants did not increase yield, nodule mass per plant, or leaf and grain N concentration. Small, but inconsistent, changes in total P concentration of grain were obtained from inoculation. Soil inoculants were not superior to seed‐applied inoculants for soybeans. These results combined with recent findings of other investigators (personal) communications from G. E. Ham and R. E. Smith) suggests that yield responses to soil or seed inoculants are unlikely in Cornbelt soils where soybeans are grown with some regularity because of a sufficient population of “native” rhizobia. There appears to be little justification for recommending in oculation of soybeans except where soybeans are to be planted in a field for the first time or where a previous crop was poorly nodulated.
Effect of Leaf Shape and Plant Population on Rate of Fruiting Position Appearance in Cotton1
Authors: Kerby T. A. , Buxton D. R. 
Published: July 2010

AbstractRate of appearance of fruiting positions in cotton (Gossypium hirsutum L.) is an important component of earliness. The objective of this research was to evaluate the influence of leaf type (size) and population density on rate of fruiting position appearance along branches of individual plants. Normal, okra, and superokra leaf cotton plants were grown in rows 51 cm apart in irrigated basins at 11.2 and 18.5 plants/m2 in 1973, and 10.0 and 20.0 plants/m2 in 1974. Fruiting positions reaching anthesis were tagged daily. Rate of appearance was determined by observing the number of days between successive fruiting branches (sympodial plastochron) and the number of days between first fruiting positions of successive fruiting branches (monopodial plastochron). Plants grown in high population densities generally had larger sympodial and monopodial plastochrons (longer time intervals between appearance of fruiting positions) than plants in the low population. Okra and superokra plants had smaller monopodial plastochron and larger ratios of sympodial to monopodial plastochrons than normal leaf plants. Sympodial plastochron increased from early to mid‐season and then declined. Monopodial plastochrons increased from early season to plateau values at mid‐season. The seasonal changes in plasto‐chrons did not appear to be related to changes in temperature. This study shows that both leaf type and population density affect rate of fruiting position appearance and earliness in cotton but changes in temperature found in fields may have little effect on plastochrons.
Influence of Rhizobium japonicum Strains and Inoculation Methods on Soybeans Grown in Rhizobia‐populated Soil1
Authors: Boonkerd Nantakorn , Weber D. F. , Bezdicek D. F. 
Published: July 2010

AbstractIndigenous rhizobia in field soils previously planted to soybeans (Glycine max L. Merr.) usually preclude the nodulation by rhizobia applied as inoculants. However, the introduction of superior N fixing strains is still considered an important management goal. This study was conducted in a rhizobia‐populated field soil (Fluvaquentic dystrochpepts) using three strains of R. japonicum (62, 76, and 110). Each strain was used at 1× and 10 × rates of peat inoculum applied to the seed and at 1×, 10× and 100× rates of liquid inoculum applied over the seeds in the row. The objective was to determine if applied strains could compete with indigenous rhizobia for nodule sites and enhance N fixation. Inoculation by either method or with any rate or strain did not effect nodulation or plant growth. However, when the level of strains 62 and 110 in broth was increased 10 and 100 times the initial rate, the recovery of applied strains increased. Peat inoculum applied at 10 times the initial rate did not appreciably change the serogroup distribution in nodules. Strain 76 did not form an appreciable percentage of the nodules at any rate or method of inoculation because it was less competitive than the predominant strains in the field soil. Increased inoculum rates applied by different methods, while only partially successful in displacing indigenous soil rhizobia, demonstrate the need for continued evaluation of innovative methods of applying efficient rhizobia which can compete for nodule sites in the field.
In situ Root Studies Using Neutron Radiography1
Authors: Willatt S. T. , Struss R. G. , Taylor H. M. 
Published: July 2010

AbstractMost studies of plant roots growing in soil involve destructive sampling or involve estimates of root growth only at a soil‐viewing surface interface where growth conditions are different from those in bulk soil. This research tested the feasibility of using preferential attenuation of thermal neutrons by roots to overcome these two disadvantages of current methods. Radiographs were obtained of soybean [Glycine max (L.) Merr.] and corn (Zea mays L.) roots growing through bulk samples of unsaturated soil.Plants were grown at 22 C in loamy sand soil wetted to 9% volumetric water content. The soil was contained in either 2.5‐ or 5.0‐cm thick aluminum boxes. At irregular intervals, the sample containers were transferred into a 6° diverging 0.04eV (thermal) energy neutron beam obtained from the Ames Laboratory Research Reactor, U. S. Energy Research and Development Administration, Iowa State University, Ames, Iowa. The samples were exposed to the neutron beam for 8 to 10 min. This exposure allowed about 5 × 109 neutrons/cm2 to strike an indium collector plate attached to the rear of the container. After the collector plate was removed from the neutron beam, photographic film was attached to the collector plate for 1 ½ hours; then the film was processed.The preferential neutron scattering by the roots allowed elongation rates of soybean radicles or seminal roots of corn to be determined easily through either 2.5‐ or 5‐cm thick soil samples. Small lateral roots of either species were less clearly distinguishable and resolution must be improved before elongation rates can be measured for laterals with a diameter smaller than 0.33 mm. Plants were not harmed visibly by the thermal neutron fluxes used in these experiments.
Accumulation and Redistribution Pattern of Dry Matter and N in Triticale and Wheat Varieties under Water Stress Condition1
Authors: Lal Pyare , Reddy G. G. , Modi M. S. 
Published: July 2010

AbstractAccumulation of dry matter and N in a cereal plant indicates its potentiality for yield, but its mobilization to the reproductive sink is important for higher economic yield. We studied this mobilization in triticale (Triticale hexaploide Lar.)), a recently developed crop which might compete with wheat (Triticum aestivum L.). The objective was to screen varieties of triticale relative to wheat for their high translocation ability and N utilization efficiency.A field experiment was conducted on silt loam soil (Typic Hapludoll) during 1973–74 at Pantnagar, India. Treatments consisting of five varieties each of triticale (‘Bronco 90’, ‘Armadillo PM 112’, ‘Armadillo PM 113’, ‘Armadillo PM 114’, and ‘Armadillo PPV 13’) and wheat (‘C 306’, ‘K 65’, ‘K 68’, ‘Kalyansona’, and ‘Sonalika’) were arranged in a randomized block design with five replications. Plant samples were collected from a 0.125‐m2 area for dry matter and N content studies in culm, lower leaf, flag leaf, spike chaff, and grain at successive stages. The loss of dry matter from different plant parts was assumed to be translocated to the grains.Both triticale and wheat cultivars differed greatly in their capacity to accumulate and redistribute dry matter and N. Bronco 90 and Armadillo PM 112 triticale cultivars, and C 306 and K 65 wheat cultivars, accumulated greater amounts of dry matter and N than the other varieties. The dry matter losses, presumably because of translocation to kernels, varied from 12.9% (Armadillo PM 113) to 36.9% (Armadillo PM 112) in triticale, and from 19.2% (C 306) to 31.6% (K 68) in wheat. In translocation of N to grain, Bronco 90 (58.4%) and Kalyansona (61%) were the most efficient cultivars of triticale and wheat, respectively. Such cultivars should be selected for further improvement in yield. Armadillo PM 112 and C 306, the top yielding cultivars in respect of grain, removed the largest quantities of N (75.7 and 5.93 kg N/ha). On an average, triticale cultivars removed larger amounts of N than the wheat. Selecting varieties that are more efficient in use of N would help in economizing N fertilizer, which is urgent in today's crop production.
Seasonal Production, Perloline Content, and Quality of Fescue After N Fertilization1
Authors: Fribourg Henry A. , Loveland Richard W. 
Published: July 2010

AbstractThe already great importance of tall fescue (Festuca arundinacea Schreb.) as a forage grass could be enhanced if its yield and quality during summer, fall, and winter could be increased. The effects of several rates (from 50 to 700 kg/ha) and times (March, May, July, September, October, November—singly or in different combinations) of N fertilizer application on tall fescue seasonality of production and quality were evaluated over a 3‐year period. Herbage was removed at a 5‐cm stubble whenever growth reached 8 to 10 cm. Variables measured included dry matter production in vitro digestible dry matter (IVDDM), and contents of perloline, and total and nitrate N. Nitrogen fertilizer increased yield and total N, NO3‐N and perloline in harvested forage. Season affected IVDDM more than N fertilization, although the higher or more frequent N rates increased IVDDM indirectly. Increases in total N, NO3‐N and perloline were evident in individual harvests soon after N applications, but yield increases were not observed until precipitation occurred. Summer N fertilization to increase yield is therefore questionable unless soil moisture is present, and it may result in higher NO3‐N and perloline contents than are desirable for quality forage. Applying more than 50 kg N/ha in September did not increase appreciably quality and quantity of fall forage. Late fall N fertilization did not increase measurable winter forage production, but it did increase earliness and yield the following spring.
Use of Methanol‐Water Solutions for Freeze Protection of Tensiometers1
Authors: Wendt C. W. , Wilke O. C. , New L. L. 
Published: July 2010

AbstractThe use of tensiometers to schedule irrigations has teen limited primarily to summer crops because of water freezing in the tensiometers during the winter months. Since methanol‐water mixtures have lower freezing points than water, a greenhouse study was conducted using an Olton loam soil (Acridic Paleustolls) to determine the effect of a methanol‐water mixture (30% methanol by volume) on tensiometer readings and plant growth. No major effects of tensiometer readings or plant growth Mere noted. Results from a field demonstration on irrigated winter wheat (Triticum aestivum L.) indicate that tensiometers with such mixtures can be used to estimate soil water tension changes at atmospheric temperatures down to −18.8 C.
A New Fiber Optic Technique for Measuring Root Growth of Soybeans Under Field Conditions1
Authors: Sanders J. L. , Brown D. A. 
Published: July 2010

AbstractAn experimental procedure, described in this paper, involved the use of a highly refined fiber optic duodenoscope for observing and photographing root development patterns within a soil profile. The root was monitored by inserting the unit into a transparent Plexiglas tube imbedded within the root zone. This technique permitted the observation and quantitative characterization of the root system throughout the entire growing season, which, until this time, has been excessively expensive, laborious, time consuming, and nonreproducible. Root lengths for soybeans [Glycine max (L.) Merr. ‘Lee‐68’] at the R‐7 stage of maturity were calculated and compared by the duodenoscope and the Newman‐Core methods at four depth‐intervals. The depth intervals were reported as 0–18, 18–36, 36–54, and 54–72 cm in a Peridge silt loam (Typic Paleudalf; fine silty, mixed, mesic). Total root lengths estimated by the Newman‐Core method for the 0 to 72 cm depth‐intervals was 56.36 m, while the estimate by the scope was 52.84 m. Although both methods gave similar results, the scope tended to estimate a greater root length than did the soil cores at all depths except the 0 to 18 cm. Both methods showed that the majority of the root system was in the 0 to 18 cm depth; 68% for the soil cores and 47% for the scope. Root density (cm/cm3) decreased with soil depth from 10.58 to 1.52 by the soil core method and from 6.77 to 2.83 for the scope measurement. The coefficient of variation was 52.64 and 14.10 percent for the core and scope measurements, respectively. The study indicated that the duodenoscope method can be used as a nondestructive technique for quantitatively measuring soybean root systems throughout the growing season.
Seedlings Stage Drought Response in Rice1
Authors: O'Toole J. C. , Aquino R. S. , Alluri K. 
Published: July 2010

AbstractDrought‐related problems of crop establishment occur in many of the world's rainfed rice (Oryza sativa L.) growing areas. Little effort has been made to breed improved cultivars for these chronically drought‐prone areas. In this note, we report investigations on the feasibility of controlled‐environment evaluation of seedling stage drought resistance among rice cultivars. Rice cultivars were grown in a glasshouse to the three leaf stage and then placed in a growth chamber with programmed diurnal changes in light, temperature, and humidity. After a 10‐day exposure to growth chamber conditions without irrigation, the trays were moved back to the glasshouse, watered, and after 3 days the seedling survival percentage determined. A wide spectrum of seedling survival percentages was found among the 206 rice cultivars screened by this method. The technique illustrated its capability to identify well‐adapted, traditional cultivars from areas where seedling stage drought is a chronic problem. Thus the technique can identify donors of this trait for hybridization purposes and can monitor the trait through a varietal improvement process.
A Comparison of Osmotic Potential, Elastic Modulus, and Apoplastic Water in Leaves of Dryland Winter Wheat1
Authors: Campbell G. S. , Papendick R. I. , Rabie E. , Shayo‐Ngowi A. J. 
Published: July 2010

AbstractPrevious models which describe the water‐content potential relationship for plant tissue do not account for die presence of apoplastic water in the tissue and its variation with water potential. This could cause errors in determination of tissue water parameters which are sensitive to plant water deficits. The theory was modified to account for apoplastic water fraction and used to determine the osmotic potential at full and zero turgor and tissue elastic modulus from moisture release curves for leaves of three winter wheat (Triticum aestivum L.) cultivars grown under moderately high and low stress environments in eastern Washington. Moisture release curves for individual leaves were obtained using a pressure chamber. Apoplastic water content was obtained independently from moisture release curves of frozen leaves using a hydraulic press. Osmotic potential at full and zero turgor showed significant responses to environment with leaves from the drier location having osmotic potentials 5 bars or more lower than leaves from the more moist site. Shifts in osmotic potential from wet to dry portions of the season were also about 5 bars. Apoplastic water fraction and elastic modulus were relatively insensitive to environment, averaging around 0.3 and 200 bars, respectively. Significant cultivar differences were found in tissue osmotic potential, but these did not correlate with performance of the cultivars in droughty environments. The study showed that apoplastic water in tissue, if not corrected for, markedly influences osmotic potential measurements using expressed cell sap since this water, which is essentially solute‐free, dilutes the cell sap when the membranes are destroyed. The tissue water parameters studied provide further insight on physiological factors important in plant resistance to moisture stress.
Grain Yields and Land Equivalent Ratios from Intercropping Corn and Soybeans in Minnesota1
Authors: Crookston R. Kent , Hill David S. 
Published: July 2010

AbstractIntercropping, or growing two or more crops simultaneously on the same field, is a farming practice that has recently received attention from agronomic scientists as a means of improving land usage. The objective of this study was to determine whether present‐day corn (Zea mays L.) hybrids intercropped with soybean (Glycine max L. Merrill) at conventional row spacings would increase land usage in Minnesota.Two different intercropping patterns were examined, each under three environments. The first pattern consisted of growing the two crops in combinations of alternating 76‐cm spaced rows. The patterns were: single alternate rows, three rows of each crop alternated, six rows of each crop alternated, and twelve rows of each crop alternated. Both crops were planted on the same day. In the second pattern, the two crops were grown in single, alternating, 38‐cm rows, with corn maturity rating, population, and planting date as variablesAlthough corn yields were significantly improved in some combinations of the first pattern, accompanying soybean yields were always reduced to the extent that none of the combinations made significantly different use of the land than did sole cropping. In many combinations of the second pattern, both corn and soybean yields decreased and land usage was thereby significantly reduced. In the other combinations of the second pattern land usage was unaffected. Minnesota land use efficiency was thus not improved by intercropping corn and soybeans in a variety of management combinations. Management approaches that might be expected to result in improved land usage are postulated.
No‐Tillage Maize Production in Chemically Suppressed Grass Sod1
Authors: Elkins D. M. , Vandeventer J. W. , Kapusta G. , Anderson M. R. 
Published: July 2010

AbstractFor no‐tillage maize (Zea mays L.) planted in sod, production usually involves the use of a contact herbicide to chemically mow or kill the grass sod. Such a procedure often necessitates costly forage reestablishment and subjects the land to water and wind erosion hazards during noncrop periods. Substantial acreage of rolling, erosive land presently is being row cropped. Field studies on different soil types were designed to investigate: a) the feasibility of chemically suppressing the grass sod for maize production; b) maintaining a sod cover for erosion control; c) providing sufficient forage for fall and winter animal grazing.More than 20 treatments involving growth retardants and sublethal herbicide rates were evaluated for maize production in tall fescue (Festuca arundinacea Schreb.) and Kentucky bluegrass (Poa pratensis L.) sods at two southern Illinois locations from 1975 to 1977.The growth retardants which resulted in the best combination of maize yield and grass production in these experiments were maleic hydrazide (1,2‐dihydro‐3,6‐pyridazinedione), fluridamid (N‐[3‐[1,1,1‐trifluoro methylsulfonyl) amino]‐4 methylphenyl]acetamide), and mefluidide (N‐[2,4‐dimethyl‐5[[(trifluoromethyl) sulfonyl]amino]phenyl] acetamide.The herbicides which most nearly met experimental objectives were glyphosate (N‐(phosphonomethyl)glycine), glyphosate plus atrazine (2‐chloro‐4‐(ethylamino)‐6‐(isopropylamino)‐s‐triazine), metolachlor (2‐chloro‐N‐(2‐ethyl‐6‐methylphenyl)‐N‐(2‐methoxy‐l‐methylethyl) acetamide), metolachlor plus atrazine, and dalapon (2,2‐dichloropropionic acid). In most instances, it was necessary to apply a band of paraquat (1,1′‐dimethyl‐4,4′‐bipyridiniumion) over each row for acceptable maize yield.In these experiments, it was possible to obtain good maize yields while maintaining at least 50% of the grass sod with little or no erosion observed. This method offers the potential for a combination of maize production and grazing on erosive land.