bluuebunny/crossref_metadata_2025_split huggingface dataset:
Temperature and the Development of the Taproot and Lateral Roots of Four Indeterminate Soybean Cultivars1
Authors: Stone J. A. , Taylor H. M. 
Published: July 2010

AbstractSoil temperatures vary with depth and time within and among years. An experiment was conducted to quantitatively evaluate the effects of temperature on the development of the taproot and lateral roots of four soybean (Glycine max (L.) Merr.) cultivars at four temperatures. ‘Beeson’, ‘Hawkeye 63’, ‘Wayne’, and ‘Harosoy 63’ soybeans were grown at 17, 21, 25, and 29°C, using a specially designed, constant‐temperature, water bath system. The water bath was located in a temperature‐modified greenhouse where air temperature ranged from 20 to 35°C during the 12‐month experimental program. Serial measurements of taproot and lateral root tip location and number of primary nodes were recorded on alternate days until 19 days after emergence. A primary node was defined as the position at which one or more 1st order laterals emerge from the taproot. The rate of taproot extension increased with temperature, decreased with time at temperatures greater than 17°C, and was greater for the Beeson and Hawkeye 63 cultivars than for the Wayne and Harosoy 63 cultivars when averaged over time. The rate of lateral root extension increased with temperature, increased with time at temperatures less than 29°C, and was greater for the Beeson and Hawkeye 63 cultivars than for the Wayne and Harosoy 63 cultivars at temperature treatments greater than 17°C when averaged over time. The number of primary nodes varied with depth, time, and cultivar. The greatest number of nodes occurred 2.5 to 7.5 cm below the vermiculite surface. The Beeson and Hawkeye 63 cultivars had fewer primary nodes than the Wayne and Harosoy 63 cultivars. The results indicate that the depth of soybean root penetration can be altered to increase available water during periods of stress by cultivar selection and changes in soil temperature.
N2‐Fixation in Field Beans Quantified by 15N Isotope Dilution. I. Effect of Strains of Rhizobium phaseoli1
Authors: Rennie R. J. , Kemp G. A. 
Published: July 2010

AbstractMost soils sown to field beans (Phaseolus vulgaris L.) contain indigenous Rhizobium phaseoli; thus, few studies have evaluated the effect of different strains of R. phaseoli on N2 fixation and yield of bean cultivars. Since western Canadian soils contain no indigenous R phaseoli, strains were screened for their ability to fix N2 in two bean cultivars, Aurora and Kentwood. Initially, the N2‐fixing ability of 19 strains of R phaseoli was determined in vitro. The best were then compared with 16 superior Centro Internacional de Agricultura Tropical strains in a 2‐ year International Bean Inoculation Trial in the field in association with the same two small white bean cultivars. 15N isotope dilution at levels of 15N natural abundance in the field showed the % Ndfa (percentage plant N derived from the atmosphere) averaged 50% for Aurora but only 32% for Kentwood over all 16 strains. The % Ndfa did not vary between the two experimental years, but due to different levels of soil N, yield and actual amounts of N2 fixed did vary. Aurora averaged 70 kg N ha−1 and Kentwood 37 kg N ha−1 fixed. Some strains fixed more than 100 kg N ha−1 in Aurora, resulting in dry matter and N yields in excess of uninoculated treatments receiving 40 or 100 kg fertilizer N ha−1. Strains of R phaseoli from high temperature soils of Latin America fixed high amounts of N2 in association with temperate bean cultivars under conditions of low temperature growth (10 to 23°C). CIAT strains 632,899, 640, and 904 and commercial Nitragin were highly efficient N2 fixers with Aurora as were CIAT strains 952, 161, 166, and commercial Nitragin with Kentwood. Thus, R. phuseoli are as efficient as other rhizobia in supplying fixed N2 to their host plant and, in N2‐fixing mode, certain bean cultivars can meet their genetic yield potential in the field without the addition of fertilizer N.
Dry Matter Production in Tops and Roots of Winter Wheat as Affected by Phosphorus Availability During Various Growth Stages1
Authors: Sutton P. J. , Peterseon G. A. , Sander D. H. 
Published: July 2010

AbstractThe timeliness of P availability to a plant is important for maximum plant growth. There is little information pinpointing the critical time(s) in the life cycle of winter wheat (Triticum aestivum L.) at which P uptake is the most important for maximum growth response. The objectives of this research were: i) to determine the effects of removing P from the growing medium during progressive stages of growth on dry matter production and P uptake of winter wheat; and ii) to compare the P demand pattern of winter wheat with that known for spring wheat. ‘Centurk’ winter wheat was grown using a modified Hoagland's nutrient solution in a greenhouse environment. Treatments consisted of evaluating the plant response to the time grown with and without available P in the nutrient solution. This was accomplished by replacing the complete nutrient solution with a nutrient solution devoid of P and allowing plants to continue growth to physiological maturity. Winter wheat had taken up sufficient P by the first node stage to ensure maximum dry matter production of the mature roots and tops. Phosphorus availability in later growth stages did not significantly increase mature root and top dry matter production. Maximum grain yield at maturity, however, was only realized when P was available through the mealy‐ripe stage (Feekes' Scale 11.2) of grain development. It appears that after noding stage only a small amount of P may be needed to allow carbohydrate translocation mechanisms to function. Spring wheat differs from winter wheat in that it only requires adequate P up to heading to produce maximum grain yields.
Extractors for Neutron‐Probe Access Tubes1
Authors: Wesley Richard A. , Adams E. Ray 
Published: July 2010

AbstractExtraction of neutron probe access tubes from soils can often be time consuming and costly if not properly managed. Therefore, two neutronprobe access tube extractor units were designed, constructed, and tested for ease of use and damage‐free results. One unit was made from a tail pipe expander and was capable of extracting tubes from soils with low moisture content but resulted in time delays because of slippage on the tube and also resulted in some damaged and distorted tubes. The other unit was made from an expanding mandrel and performed acceptably on both coarse and fine‐textured soils having both high and low moisture content. This unit eliminated time delays because of slippage and virtually eliminated damaged and distorted tubes.
Interactions among a Herbicide Program, Nitrogen Fertilization, Tarnished Plant Bugs, and Planting Dates for Yield and Maturity of Cotton
Authors: Gaylor Michael J. , Buchanan G. A. , Gilliland F. R. , Davis R. L. 
Published: July 2010

AbstractThe influence of a maximum herbicide program, N rates, tarnished plant bugs [Lygus lineolaris (Palisot de Beauvois)], planting date, and interactions among these treatments on cotton (Gossypium hirsutum L.) was determined under field conditions on a Dewey silt loam (clayey, kaolinitic, thermic, Typic Paleudult) soil. High rates of herbicides caused early phytotoxicity and reduced earliness in all 3 years of this study. Total yields were reduced by herbicides in 1976 and 1978. In 1977, compensation for early season herbicide injury by the early‐planted cotton apparently resulted in higher yields in the herbicide treated plots than in untreated plots. Generally, the herbicide program reduced earliness and yields most under conditions where the potential yield was greatest (early planting, high N rates, and effective tarnished plant bug control). Yield reductions due to the herbicide program were not additive with reductions due to other factors. Effects of variable N rates on yield were inconsistent. Tarnished plant bugs reduced total yields in cotton planted late in 1976, but because early‐planted cotton had time to compensate for damage, plant bug infestations resulted in no yield loss in the early 1976 planting and in increased total yields in cotton planted early in 1977. Because of complex interactions among production practices, interdisciplinary research is needed to design optimum production systems.
Pangola Digitgrass Yield and Nutrient Uptake with Liquid and Solid N‐P‐K Fertilizers1
Authors: Mooso Galen D. , Jolley Von D. 
Published: July 2010

Abstract‘Pangola’ digitgrass (Digitaria decumbens Stent.) is an important tropical and subtropical forage species which responds dramatically to N fertilization. Responses to the application of P and K, however, or the combinations of N, P, and K are not as clearly defined. Its response to N, P, and K applied in solution has not been established. A 2‐year study to compare the effect of the application of liquid and solid N‐P‐K (9:1:4) fertilizers on digitgrass production and nutrient uptake was conducted on a Wabasso sand (siliceous, hyperthermic, Alfic Haplaquod) on the Deseret Ranches in Central Florida. There was a positive linear relationship between the amount of N‐P‐K fertilizer applied and the amount of forage produced. The concentrations of N and K were positively affected by increased N‐P‐K levels while P concentration was negatively affected. A positive linear relationship was also observed between the uptake of N, P, and K and the rate of application. The liquid fertilizer produced an average of 20.9 and 21.4% less forage than the solid for 1980 and 1981, respectively. Solid fertilizer maintained a higher N concentration in the forage than the liquid, but no differences in P and K concentrations were observed with the two forms of fertilizer. The forage treated with solid fertilizer averaged 24, 35, and 59% higher relative uptake of N, P, and K than the forage treated with liquid fertilizer, respectively. Under the conditions of the study, ammonia volatilization was probably the major reason for lower yields, N concentrations, and N uptake from the use of liquid fertilizer. The lower uptake of P and K with liquid fertilizer was associated with the lower yields obtained with this source.
Yield of Corn, Cowpea, and Soybean Under Different Intercropping Systems1
Authors: Allen James R. , Obura Robert K. 
Published: July 2010

AbstractIntercropping is presently a major method of crop production in tropical Africa, subtropical Asia, and Central and South America. With this approach, crops are planted in such a variety of combinations that the merits of intercropping as compared with monoculture are often difficult to determine. Our objective was to evaluate the merits of intercropping legumes and grasses in the United States. Corn (Zea mays L.) was intercropped with cowpea (Vigna unguiculata (L.) Walp.] and soybean [Glycine max (L.) Merr.] on a Norfolk sandy loam soil (fine, loamy siliceous, thermic Typic Paleudult). The legumes were either planted in the rows with corn or alternate to the corn rows. Control plots were monocrops of corn and the legumes, with each species fertilized according to soil test recommendations. Both dry matter and seed yield of the monocrops were higher than the individual components in the intercrops. Intercropped corn yield ranged from 46 to 90% of the reference monoculture. The lower dry matter production in the intercropped plots may have been due to competition between the corn and legume components for N. Seed yield of intercropped cowpea ranged from 42 to 56% of monoculture. Intercropped soybean seed yield ranged from 52 to 54% in 1980, and 48 to 60% in 1981 of the monoculture. Dry matter accumulation was significantly greater for the monocrops but varied non‐significantly, between the alternate and within row system. The corn‐cowpea intercrops, which had Land Equivalent Ratios (LER) up to 1.27 in 1980 and 1.32 in 1981 and Area Time Equivalent Ratios (ATER) as high as 1.19 in 1980 and 1.25 in 1981, were more productive than the corn‐soybean intercrops. The corn‐soybean combination had a maximum LER in 1980 of 1.22 and 1.10 in 1981, while the maximum ATER was 1.12 in 1980 and 1.01 in 1981. Thus, both the LER and ATER showed that intercropping resulted in greater productivity per unit of land than monocultures of the intercrop components.
Sprouting in Intact Mature Spikes of Hard Red Spring Wheat1
Authors: Bauer Armand , Black A. L. 
Published: July 2010

AbstractThe water factor's role in sprouting was defined for intact mature hard red spring wheat (Triticum aestivum L.) spikes in laboratory experiments as a prelude to developing a sprouting model. Grain and spike water concentration are essentially synonymous at harvest ripeness. Spike water concentration increased linearily by 10 g kg−1 min−1, dry wt at 69°C, when continuously misted at 19 mm h−1, while water imbibition by grain in once wetted intact spikes increased curvilinearily, varying with spike water concentration and equilibration time. Maximum imbibition rate of grain was 17 g kg−1 h−1 with wheat spike water concentration at 1450 g kg−1. Water evaporation from wetted spikes was slower at high than low relative humidity, and slower after equilibration (time for imbibition) than if drying was initiated immediately after wetting. Minimum equilibrated spike water concentration inducing sprouting was about 450 to 490 g kg−1. Sprouting was not induced by wetting field‐growing wheat during primary dehydration until the water concentration had declined to about 120 g kg−1 for at least 2 days. When cut at Feekes stage 11.3, the number of drying days required before any sprouting could be induced varied with cultivars, ranging from about 4 to more than 15 days. Sprouting potential was enhanced by wetting‐drying cycles in which the wetted interval was too brief to permit sufficient imbibition to initiate sprouting. Ninety percent of the kernels in 300 mature spikes sprouted within 8 days after misting to saturation (about 1500 g kg−1 water concentration) and maintained at a minimum of 750 g kg−1; 20% of the kernels sprouted within 28 h of initiation of wetting.
Predicting Soybean Rooting Depth as a function of Soil Temperature1
Authors: Stone J. A. , Kaspar T. C. , Taylor H. M. 
Published: July 2010

AbstractA two dimensional predictive simulation of rooting depth has been developed from data which describe the effects of root‐zone temperature on soybean [Glycine max (L.) Merr.] root development. The major inputs are equations which describe the rate of taproot and lateral root extension, node development, and the rooting angle as a function of time and temperature. The simulation predicts the extension of the taproot and 10 primary lateral roots for two groups of soybean cultivars. The output consists of a listing of serial rectangular coordinates for each root tip and a computer plot of the root system. The rooting depths predicted by the simulation agree well with field experimental data illustrating the importance of soil temperature in determining the depth of soybean root penetration in extrapolating greenhouse root extension data to a field situation.
Fruiting of Cotton. I. Effects of Moisture Status on Flowering1
Authors: Guinn G. , Mauney J. R. 
Published: July 2010

abstractYield of cotton (Gossypium hirsutum L.) is proportional to the number of bolls produced, which is influenced by flowering rate and boll retention. Previous reports have presented conflicting information on the effects of water deficit on fruiting some indicated increased flowering while others indicated decreased flowering in response to water deficit. Tests were conducted in 1978, 1979, and 1980 on an Avondale clay loam (a member of the fine‐loamy, mixed, hyperthermic family of Typic Torrifluvents) at the Arizona Cotton Research Station in Phoenix to determine the effects of plant water status at different times during the season on flowering of cotton. Water deficits decreased flowering in 1978 and 1980. A pronounced lag in response caused flowering to continue unabated during much of each stress period. Once the flowering rate declined, however, it did not start to recover until about 3 weeks after stress was relieved by irrigation. Only in 1979 did we observe more flowers in plots in which the first postemergence irrigation was delayed. The population of lygus bugs (Lygus hesperusKnight) was higher in 1979 than in 1978 or 1980. Furthermore, lygus counts were higher in irrigated than in stressed plots. Because lygus bugs have been shown to cause square shedding, early irrigation may have decreased early flowering indirectly in 1979 by increasing bug populations and resultant square shedding. We found no evidence, however, for a physiological stimulation of flowering of cotton by a water deficit.
Soybean Seed Growth II. Individual Seed Mass and Component Compensation1
Authors: Spaeth S. C. , Sinclair T. R. 
Published: July 2010

abstractSince the rate and duration of the growth of individual seeds determine final seed mass, a detailed study of these variables with respect to morphological position on individual soybean [Glycine mar (L.) Merr.] plants was undertaken. A predictable pattern of seed growth could lead to explanatory models for crop yield. Plants were grown under field conditions at Ithaca, N.Y. (soil was a fine, illitic, mesic, Glossaquic Hapludalf) and Gainesville, Fla. (soil was a loam‐siliceous, hyperthermic, Grossarenic Paleudalf). To determine the influence of morphological position on individual seed mass, rate and timing of dry matter accumulation of individual seeds at various positions on individual plants were determined from detailed observations of the initiation and termination of seed growth. multiple linear regressions of final individual seed mass on duration and position variables did not consistently account for the variation in seed size. Also, the rate of seed growth was not consistently related to easily observed properties of the plants. No pattern was identified upon which an explanatory model of seed yield could be based. The degree of compensation between mean mass per seed and seed number was determined for individual plants within a cultivar. When individual plants were first grouped according to total plant mass, mean mass per seed was negatively correlated with seed number. Estimates of component compensation which do not take into account the variation in plant size are likely to underestimate the degree of negative correlation.
Yield and Nutrient Utilization Efficiency of Irrigated Corn1
Authors: Rhoads F. M. , Stanley R. L. 
Published: July 2010

AbstractThe concept of a critical concentration of each nutrient in plant tissue, below which poverty adjustment occurs and above which luxury consumption takes place, suggests a quantitative relationship between total uptake of each nutrient and yield in the range of poverty adjustment (RPA). The purpose of this investigation was to determine the relationships between yield of two hybrids of irrigated corn (Zea maysL.) at two populations (60 000 and 90 000 plants/ha) and each of the following variables: g/kg of N, P, and K in the tissue, and total uptake of N, P, and K 4 weeks after silking. Five levels of fertilization of (N‐P2O5,‐K2O) were applied to Pioneer brand hybrids ‘3369A’ in 1977 and ‘3368A’ in 1978 on a Ruston loamy fine sand (fine‐loamy, siliceous, thermic Typic Paleudult). The N‐P2O5K2O ratio was constant at 15‐10‐15 for all treatments. Nitrogen levels were 0, 1, 2, 3, and 5 kg/1000 plants with P and K at the above ratio. Irrigation was applied to recharge the plow layer when soil‐water suction reached 0.02 MPa at the 15‐cm depth. Maximum yields for 60000 plants/ha were 12.7 Mg/ha in 1977 and 10.4 Mg/ ha in 1978. At 90000 plants/ha, maximum yields were 14.5 Mg/ha in 1977 and 9.8 Mg/ha in 1978. Grain yields were significantly correlated with g/kg of N in tissue and total N uptake each year. Lower yields in 1978 were partly attributed to hybrid differences because ‘3368A’ had as high as 0.3 barren stalks at the 90 000 plants/ha population. Nutrient utilization efficiency (NUE) for each nutrient can be expressed without units as grain yield divided by total nutrient uptake. The NUE for N remained within a narrow range (61 to 67) in the RPA regardless of yield and population where the number of barren plants was not significant. Values of NUE for P and K reached maximum levels in the RPA.
Optimum Spacing of Preplant Bands of N and P Fertilizer for Winter Wheat1
Authors: Maxwell T. M. , Kissel D. E. , Wagger M. G. , Whitney D. A. , Cabrera M. L. , Moser H. C. 
Published: July 2010

AbstractIn previous field studies a 46 cm spacing of preplant bands of N and P fertilizer has caused uneven growth of winter wheat (Triticum aestivumL.), with better growth immediately atop the preplant bands. Narrower spacing of fertilizer bands could improve plant growth uniformity and grain production by winter wheat. The objective of this study was to evaluate N‐P fertilizer band spacing on wheat growth and grain yield. The effect of P band spacing on fertilizer P uptake from a preplant band was studied in the greenhouse with winter wheat. Phosphorus uptake from the fertilizer band was influenced by the lateral distance from the wheat row to the P band at 33 days after planting. By 40 days after planting, however, uptake of fertilizer P was the same from bands placed 0, 10, and 20 cm from the wheat row, while P uptake was significantly less from the band placed 30 cm from the row, apparently due to another row of wheat shielding the fertilizer P from uptake. Field studies consisting of combinations of spacings of preplant bands (25, 38, and 50 cm) and rates of P fertilizer (0,6, 12, and 24 kg/ha), all with 84 kg N/ha, were conducted on winter wheat. All treatments were deep‐placed preplant band applications of liquid ammonium polyphosphate (APP, 10‐15‐0) and anhydrous ammonia (82‐0‐0). Wheat was drilled perpendicular to the direction of the preplant band application. Early season growth of winter wheat increased with increasing P rate and by decreasing the distance between preplant bands. Final grain yield, however, was influenced only by P rate, and not by P band spacing. Plant samples taken from 12.5 cm of drill row centered over the band and 12.5 cm of drill row centered between preplant bands of each treatment indicated differences between those areas in dry matter production, P uptake, spike density, and grain yield due to P rate and band spacing. Thus, more uniform growth resulted from the closer band spacing of 38 and 25 cm which could result in higher grain yields under optimum wheat production conditions.