bluuebunny/crossref_metadata_2025_split huggingface dataset:
Postemergence Control of Kochia and Russian Thistle in Early Spring1
Authors: Smith D. T. , Wiese A. F. , Cooley A. W. 
Published: July 2010

AbstractIn semiarid regions, soil preparation precedes seasonal spring rains to conserve moisture. However, the early emergence of kochia [Kochia scoparia (L.) Schrad.] and Russian thistle (Salsola kali L. var. tenuifolia Tausch) severely competes with early‐seeded crops, such as sugarbeets (Beta vulgaris L.), or requires additional soil tillage prior to planting other crops. Objectives of this study were to evaluate postemergence control of kochia and Russian thistle for potential use in minimum till farming or postemergence control in established sugarbeets. Herbicides, with foliar activity, were applied at various stages of weed development in several field experiments on loam soil (mixed, thermic Paleustalfs and Paleustolls). Herbicidal efficacy was evaluated with regard to vegetative development of the weeds.Early growth of kochia and Russian thistle was highly diverse in the spring, which would preclude herbicide applications at prescheduled calendar dates before planting crops. Herbicidal control with postemergence applications was best when weeds were small but growing vigorously. Of the herbicides evaluated, only paraquat (1,1′‐dimethyl‐4,4′‐bipyridlnimn ion) at 0.6 kg/ha consistently controlled both species. Complete postemergence control of kochia and Russian thistle was not feasible with diuron [3‐ (3,4‐dichlorophenyl)‐1,1‐dimethylurea], atrazine [2‐chloro‐4‐(ethylamino)‐6‐(isopropylamino) ‐s‐triazine]; herbicides which might also provide residual weed control in subsequent tolerant crops. In sugarbeets, kochia up to 2.5 cm tall, was effectively controlled with phenmedipham (methyl m‐hydroxycarbanilate m‐methylcarbanilate) at 1.1 or 1.7 kg/ha without injury to the crop.
Cottonseed Viability After Long‐Time Storage1
Authors: Stewart J. McD. , Duncan E. N. 
Published: July 2010

AbstractLongevity of seed and knowledge of the conditions required to maintain seed viability are important in the preservation of germplasm. Cottonseed (Gossypium hirsutum L., G. barbadense L., G. thurberi Tod.) storage experiments were initiated in 1937 to establish conditions required to maintain long‐term viability of cotton. This is the final report of those experiments.In one experiment, seed (G. hirsutum L.) of two cultivars were stored in sealed containers at moisture levels of 7, 9, 11, 13, and 14%, and at temperatures of 32, 21, and 0 C. For the last 10 years, only those seed stored near 0 C were carried forward, since all seed stored above this temperature were nonviable. Germination trials were conducted at 25 C for a 10 day period. Seeds containing 11% or less moisture and stored near 0 C had approximately 60% germination after 37 years.In a related experiment cottonseed grown during the 1920's and 1930's in Arizona were tested for germinability. These seeds were stored unsealed at ambient temperature from the year of production until 1957. Thereafter they were sealed and stored cold. The oldest viable seed lots were produced in 1929 and had a maximum germination of 60% in 1974. Several of the pregerminated seed were grown to mature plants. This probably represents the oldest recorded viable cottonseed.
Field Studies of the Conductance of Wheat Leaves and Transpiration
Authors: Denmead O. T. , Millar B. D. 
Published: July 2010

AbstractLight and water stress appear to be the main factors determining the short‐term variation of stomatal aperture in the field but their joint influences have seldom been studied in the natural environment. We have examined the effects of the irradiances and water potentials of leaves of field‐grown wheat plants (Triticum aestivum L. ‘Heron’) on their conductances for water vapor and on canopy transpiration.Water potentials were measured by thermocouple psychrometry or estimated from water flow rates and plant resistances. Conductances were measured with a diffusion porometer or calculated from meteorological measurements inside the canopy. The latter data also permitted calculation of leaf irradiances and transpiration rates.Provided leaf water potentials were higher than certain critical values (established by us in a previous study), leaf conductance (c cm s‐1) was linearly related to the net irradiance of the leaf (R1, W m‐2) by the equation c = 0.05 + 0.0020 R1, with a correlation coefficient of 0.90 and a standard error of estimate of 0.11 cm s‐1. This relationship applied to green leaves at all stem positions in the canopy up to a net leaf irradiance of > 500 W m‐2.At and below the critical water potentials, stomatal aperture was controlled by leaf water status rather than irradiance. In cases of mild water stress, induced, for example, by an excessive evaporation demand, it appeared that leaf conductances decreased just sufficiently to keep water potentials at their critical levels, thereby limiting canopy transpiration to a maximum rate which, in our case, was 0.6 mm h‐1. In severe water stress, complete stomatal closure occurred at leaf water potentials about 10 bars less than the critical values and appeared to occur first in leaves at lower positions on the stem.
Foliar Fertilization of Soybeans During the Seed‐filling Period1
Authors: Garcia L. Ramon , Hanway John J. 
Published: July 2010

AbstractFoliar fertilization of soybeans (Glycine max (L.) Merr.) with N, P, K and S during the seed‐filling period promises to increase soybean yields. Such foliar applications could be used to avoid the depletion of these nutrients in the leaves and the resulting reduction in photosynthetic rate during this period due to poor nutrient uptake from the soil and translocation of these elements from the leaves to the developing seeds. Field experiments were conducted to test this hypothesis by spraying soybeans with solutions of N, P, K, and/or S in different proportions and at different times and rates. We supplied N primarily as urea, P primarily as poly‐phosphate, K with the P as potassium polyphosphate or with the S as potassium sulfate. Very significant yield increases were obtained from two to four sprayings on different soybean cultivars at different experimental sites between developmental stages R5 and R7. The optimum proportion of N:P:K:S in the solution 10:1:3:0.5. a proportion similar to that of these elements in the seeds. The optimum rate of total nutrient application was about 80 + 8 + 24 + 4 kg/ha of N + P + K + S, respectively. Yield increases were due to increases in numbers of harvestable seeds, not seed size.The results indicate that foliar fertilization during the seed‐filling period can become a very practical method for increasing soybean yields.
Amino Acid Patterns of Kidney Beans Grown Under Different S and K Regimes1
Authors: Hojjati S. M. 
Published: July 2010

AbstractThe protein of kidney beans (Phaseolus vulgaris L.), an important food crop, is poor in S‐containing amino acids and needs improvement. Solution and sand‐culture studies have shown that S fertilization increases the concentration of S‐containing amino acids in several crops. K application affects protein composition of some crops. The objective of this research was, therefore, to determine the amino‐acid concentrations of ‘Naze’ kidney beans and to study the effects of soil‐SO42‐ levels and K2SO4 application on grain yield and amino‐acid composition, especially the concentration of methionine.An area of Xerollic Calciorthid, fine, vermiculitic, chermic soil which had been used previously for a S‐fertility study with wheat (Triticum aestivum L. em. Thell.) was used for this trial at Pahlavi University, Shiraz, Iran. The design of the experiment was a split plot with K2SO4, levels as main‐plot treatments and the prior S levels constituting the split‐plot treatments. (NH4)2HPO4 was applied uniformly at 200 kg/ha. Kidney beans were seeded at the rate of 75 kg/ha.Proximate protein analyses were made by determining total N content and multiplying by a factor of 6.25. Tryptophan was analyzed colorimetrically and the other amino acids were determined in a Beckman Spinco amino‐acid analyzer. Chemical scores reflecting protein quality were calculated by FAO instructions.Neither K2SO4 fertilization nor the prior S treatments had any effect on yield of dry matter or grain, ratio of grain to total dry matter, or grain‐protein concentration. Methionine concentration was positively correlated with soil‐SO42‐ level (r = 0.75; significant at the 1% level.). The first limiting amino acid was methionine, followed by valine and/or isoleucine. Tryptophan was not limiting. Regression equations for predicting methionine from soil‐SO42‐ levels and valine and tryptophan from total‐protein concentrations are presented.Sulfur application may increase the methionine concentration of bean protein, but the large amounts of S required and the high costs involved appear to limit the usefulness of this approach for improving protein quality.
Influence of Terminal Bud Removal on the Growth and Seed Yield of Soybeans1
Authors: Bauer M. E. , Pendleton J. W. , Beuerlein J. E. , Ghorashy S. R. 
Published: July 2010

AbstractIn recent years soybean (Glycine max (L.) Merr.) yields seem to have reached an upper limit under prevailing moisture and temperature conditions using the current set of production practices. The present study was conducted to determine if changes in soybean growth resulting from removal of the terminal bud during vegetative or early reproductive stages of development would increase seed yield. The principal objectives were to determine if removal of the terminal bud of indeterminant varieties of soybeans would increase seed yields by 1) increasing the number of nodes available for pod set or 2) decreasing apical dominance. Several field experiments with treatments at different stages of development at time of bud removal, methods of removal, cultivars, seeding rates, and row widths were conducted during 2 years on Flanagan silt loam soil, a member of the fine, montmorillonite, mesic Aquic Argiudolls. Data were collected on height, lodging, maturity, number of branches, leaf area index, distribution of dry matter among pods and seeds, leaves, petioles, branches, and stems, seed yield, and 100‐ seed weight.Removing the apical bud increased the number of nodes on branches and decreased the number of nodes on main stems, leaving the total number of nodes unchanged. The dry weight of vegetative organs was decreased by removal of the terminal bud, but seed yields were nearly constant. Removal of the terminal bud prior to the start of flowering increased branching and lodging, reduced leaf area index, and delayed maturity slightly. When the terminal bud was removed after the start of flowering, height, leaf area index, and lodging were reduced, compared to the control. The method of bud removal (hand‐pinching vs. mechanical‐mowing), cultivar, and planting density had little effect on growth and yield. From the data we concluded that, although the proportion of reproductive development compared to vegetative growth was increased by removal of the terminal bud, seed yields were unchanged.
Relationship Between Nitrogen Analysis of Soybean Tissues and Soybean Yields1
Authors: Pal U. R. , Saxena M. C. 
Published: July 2010

AbstractIn order to determine the applicability of N analysis of plant tissues as a diagnostic tool for N nutrition, it is essential to study the N status of soybean [Glycine max (L.) Merr.] plants under varying N supply. Field experiments were conducted to determine the effect of N fertilization at the rates of 0, 25, 50, 100, and 200, and 300 kg N/ha on the N concentration and accumulation in different plant parts of nodulating (inoculated and un‐inoculated) and non‐nodulating isolines of ‘Clark’ and ‘Harosoy’ soybeans at various stages of growth and to correlate the N status of soybean plants with yields.The N concentration in stems, leaves, and petioles decreased with plant age, whereas in pods the N concentration increased. In contrast, N accumulation in stems, leaves, petioles, and whole plant followed a sigmoid pattern with plant development, while in pods it increased linearly. The rate of N accumulation (kg/ha/day) followed a bell‐shaped pattern and was maximum during the pod‐filling stage. Nitrogen fertilization had little effect on N concentration, amount of N in different plant parts or whole plants, N accumulation rate and seed yield/plant in inoculated nodulating isolines. However these attributes were increased conspicuously in non‐nodulating isolines and brought to the levels of inoculated nodulating isolines at higher rates of N fertilization (i.e., 200 and 300 kg N/ha). The uninoculated nodulating isolines were similar to non‐nodulating isolines in virgin soils for soybean cultivation.Total N concentration and NO3‐N content of leaves showed better correlation with seed yields than total N accumulation in leaves/plant and total N accumulation/ plant. A total N concentration of 4.0% to 4.5% at 65 days was associated with highest yields in both ‘Clark’ and ‘Harosoy’. About 1900 ppm NO3,‐N content of leaves at 50 days in ‘Clark’ and about 1450 ppm NO3,‐N content of leaves at 65 days in ‘Harosoy’ were associated with highest seed yields. Based on the correlation values in different seasons for the two cultivars, total N concentration (%) seemed to be the best diagnostic criterion for N nutrition of soybeans.
Effect of Cultivar, Seeding Rate, and Nitrogen Fertilization on Kentucky Bluegrass‐Perennial Ryegrass Turf Mixtures1
Authors: Niehaus Merle H. 
Published: July 2010

AbstractPerennial ryegrass (Lolium perenne L.) (RG)‐Kentucky bluegrass (Poa pratensis L.) (BG) mixtures, seldom recommended in the past, are becoming more popular since the development of several turf‐type RG cultivars. Older RG cultivars produce poor quality turf because of coarseness and poor mowing quality. The objective of this study was to determine whether a relatively new turf‐type RG cultivar can be grown in a mixture with BG without sacrificing turf quality.A series of mixtures containing one of three RG cultivars (‘Manhattan,’ ‘Pelo,’ and ‘Linn’) and one of three BG cultivars (‘Pennstar,’ ‘Windsor,’ and ‘Kenblue’) was planted on a Typic Fragiudalf soil (Wooster silt loam) in the field in 1972. Three RG seeding rates (0.25, 0.5, and 1.0 kg/100 m2) and two N fertilizer rates (1.7 and 3.4 kg/100 m2) were used. BG was seeded at 1 kg/100 m2 on all plots. Botanical composition of the turf was obtained by counting BG and RG tillers in four samples from each subplot. Quality was determined by rating each subplot on a 1 to 9 scale.The results indicated that Manhattan, a turf‐type RG, produced a high quality turf when mixed with any of three BG cultivars. Mixtures containing Linn, an older RG cultivar, were generally poor in quality but quality differed according to which BG cultivar was in the mixtures. Mixtures containing Manhattan RG or Pelo, an intermediate quality RG, were dominated by the RG, especially in the 2nd year, while those containing Linn RG were dominated by the BG.Mixtures containing Windsor or Pennstar BG averaged higher in quality than those containing Kenblue BG. However, this difference was not apparent in mixtures containing Manhattan RG. Seeding rate had an effect on composition, primarily the 1st year. N rates were not associated with differences in quality or composition.It is concluded that turf‐type RG can be used successfully in mixtures with BG.
Germination in Freshly Harvested Seed of Centipedegrass1
Authors: Bouton J. H. , Dudeck A. E. , Smith R. L. 
Published: July 2010

AbstractCentipedegrass [Eremochloa ophiuroides (Munro) Hack.] is an important warm‐season turfgrass which can be established by seed. Germination of seed for progeny evaluation in the shortest time would be of value in a breeding program with this grass. Therefore, freshly harvested, open‐pollinated seed was used to study the effects of different temperature regimes and scarification treatments on percent and speed of germination.Alternating temperatures of 35‐15 C with respective light‐dark periods of 12 hours each gave the highest percentage and fastest germination. Mechanical scarification greatly improved both parameters.
Residual Nitrate and Mineralizable Soil Nitrogen in Relation to Nitrogen Uptake by Irrigated Sugarbeets1
Authors: Stanford George , Carter J. N. , Westermann D. T. , Meisinger J. J. 
Published: July 2010

AbstractPreviously reported studies on N fertilization of sugarbeets (Beta vulgaris L.) in southern Idaho revealed considerable variation among sites in amounts of residual soil NO3 and N mineralized during short‐term laboratory incubations. Consequently, the amount of N fertilizer needed to achieve near‐maximum yields of sucrose differed markedly. The purpose of this study was to determine the feasibility of estimating amounts of N mineralized in the root zone during the season, taking into account site variations in temperature and soil water regimes. Residual soil NO3‐‐N and mineralizable N to approximate rooting depth were estimated for 21 field sites in 1971 and six sites in 1972. The relative contributions of these two N sources to total N uptake by the crop, in the absence of applied fertilizer N, were then assessed. Estimates of N mineralized in the upper 45‐cm soil layer for each successive month, ΔN, over a 6‐month period were derived using the expression, ΔN/ Δt = kWN (k = fraction of N mineralized during each month, Δt, adjusted for average air temperature; and W = the estimated soil water content expressed as a fraction of the available water storage capacity). Resulting estimates of the fraction of potentially mineralizable N converted to (NO3‐ + NH4‐)‐N between 1 April and 30 September ranged from 0.15 to 0.22 (mean ± S.D. = 0.18 α 0.02) in 1971 and 1972. On the average, mature sugarbeets recovered about 73% of the estimated N mineralized (6 months) plus residual NO3‐‐N. The relative contributions of these two sources of soil derived N, respectively, were approximately 66 and 75%, as estimated from multiple regression analyses.
Mn Concentration in Soybean Leaf Related to Bean Yields1
Authors: Ohki K. , Wilson D. O. , Boswell F. C. , Parker M. B. , Shuman L. M. 
Published: July 2010

AbstractCorrelation of Mn concentration in leaf tissue with seed yield for soybean (Glycine max (L.) Merr.) requires a nutrient calibration relating Mn concentration in tissue to seed yield under field conditions. The objectives of this study were to establish the relationship of Mn concentration and seed yield and the effect of sampling time on critical Mn level under field conditions. Soybean ‘Ransom’ was grown on Olustee‐Leefield sand (Ultic Haplaquod‐Arenic Plinthaquic Paleudult) with Mn rates of 0, 5.6, 11.2, 22.4, and 56 kg/ha. Leaf samples were taken at 4, 6, 9, 12, and 16 weeks after planting and the blades were analyzed for Mn.The critical level of Mn in recently‐matured leaf blades for maximum bean yield was 7 to 10 μg/g for blades sampled at 4 to 9 weeks after planting. No substantial difference in critical Mn level was observed for the early sampling period of 4 to 9 weeks after planting. At the 12‐ and 16‐week sampling periods the critical Mn levels related to bean yield were 20 and 22 μg/g, respectively. The broad transition zone between deficiency and adequacy at the 12‐ and 16‐week sampling indicated reduced sensitivity in the Mn concentration and yield relationship. The recently matured blade (blade 2) on the main plant axis is suggested for sampling at the 9‐week period after planting for a representative indication of the Mn status of soybean under field conditions.
Effects of Cutting Management on Eight Subtropical Pasture Mixtures1
Authors: Murphy W. M. , Scholl J. M. , Baretto Ismar 
Published: July 2010

AbstractRhodesgrass (Chloris gayana Kunth) and ‘Pangola’ digitgrass (Digitaria decumbens Stent.) were grown with desmodium (Desmodium intortum (Mill.) Urb), glycine (Glycine jevanica L. ‘Tinaroo’), lotononis (Lotononis bainesii Baker), or ‘Siratro’ (Macroptilium atropurpureum (D.C.) Urb) on an Oxisol near Porto Alegre, Rio Grande do Sul. They were cut every 3 or 6 weeks at 5 or 13‐cm stubble heights to simulate different grazing pressures during two growing seasons. Herbage samples were hand separated to ascertain botanical composition. Crude protein (CP) and in vitro dry matter disappearance (IVDMD) analyses were determined for each species for cutting‐frequency treatments during the first year only. Cutting at 5 cm, at either frequency, increased legume content more than cutting at 13 cm. Exceptions were glycine, which increased most with rhodesgrass when cut at 13 cm, and ‘Siratro’, which decreased under all treatments when grown with ‘Pangola’. Legume contents increased from an average of 14% in the seeding year to 31% by the beginning of the third year. During the same period, grasses increased from 50% to 63% and weeds decreased from 36% to 5%.Weed‐free, dry forage yields from all mixtures ranged from 1.24 to 7.26 metric/ha during the first year, and from 3.69 to 10.26 metric tons/ha during the second year. Yields generally were highest when mixtures were cut every 6 weeks at 5 cm, and were lowest when mixtures were cut every 3 weeks at 13 cm.The CP concentration in legumes averaged 26% when they were cut every 3 weeks at either stubble height, and 23% when they were cut every 6 weeks. Concentration in CP in grasses averaged 15% for 3 weeks, and 13% for 6‐week cutting treatments. Yields of CP from mixtures ranged from 196 to 972 kg/ha. Yields of CP were greater from rhodesgrass mixtures than from Pangola mixtures, except for the Pangola‐desmodium mixture, which had CP yields equal to, or greater than, some rhodesgrass mixtures. Estimated digestible dry matter (EDDM), determined by IVDMD, in legumes averaged 54% when they were cut every 3 weeks at either stubble height, and 51% when they were cut every 6 weeks. EDDM in grasses averaged 73% for 3‐week cuttings. Yield of EDDM was greater from rhodesgrass mixtures than from Pangola mixtures. Considering all aspects studied, we believe that mixtures of rhodesgrass with desmodium or lotononis would be best choices for improving pastures in Rio Grande do Sul. Responses to cutting indicated that rhodesgrass‐desmodium should be grazed every 3 weeks to about a 13‐cm stubble height during the growing season. Grazing to higher stubble height, rather than the lower height, should result in a well‐balanced grass‐legume mixture for grazing. A well‐balanced rhodesgrass‐lotononis mixture should be maintained in a pasture by grazing every 3 weeks to about a 13‐cm stubble height, or every 6 weeks to either stubble height. Frequent, close grazing would probably result in higher percent legume in the mixture.