bluuebunny/crossref_metadata_2025_split huggingface dataset:
Lodging Effects on a Semidwarf and Two Standard Barley Cultivars
Authors: Jedel P.E. , Helm J.H. 
Published: July 2010

AbstractCrop productivity in the black soil zones of western Canada can be affected by lodging when high biomass production and late season winds and rain occur. This experiment was conducted to assess the effects of mechanically induced lodging at different growth stages on three barley (Hordeum vulgare L.) cultivars. Five field trials were run at Lacombe, Alberta (Navarre loam, black Chernozemic), from 1985 to 1988. At anthesis, milk, soft‐dough, and hard‐dough growth stages, the semidwarf cultivar Samson, the mid‐height cultivar Leduc and the tall cultivar Johnston were subjected to lodging treatment. Yield losses for all cultivars tended to be greatest when lodging was, imposed at the milk stage with an average yield loss of 1.7 ± 0.4 Mg/ha. Significant losses also occurred with lodging at heading and soft‐dough stages with average yield losses of 1.3 ± 0.5 and 1.2 ± 0.7 Mg/ha respectively. Samson appeared to have the greatest tolerance to lodging, while Johnston had the least. Yield losses when lodging occurred at the hard‐dough stage were minimal with an average yield loss of 0.57 ± 0.49 Mg/ha. Test and kernel weights were not significantly affected by lodging. However for Johnston, kernel weight tended to be reduced by lodging and percent thin kernels was increased to 12.8% by lodging at the soft‐dough stage from 5.3% for the control. Significant yield losses can result from lodging and in areas where lodging is of concern, efforts should be made to breed for, and promote the use of, strong‐strawed cultivars such as the semidwarf cultivar Samson.
Mapping the Production and Survival of Fruit on Field‐Grown Cotton
Authors: Constable G. A. 
Published: July 2010

AbstractThe location and size of bolls on cotton (Gossypium hirsutum L.) plants influence yield and earliness, so plant mapping is being used to define plant fruiting patterns in response to pest damage or crop management. This study aimed to define patterns of fruit location, survival percentage, and final boll size that could provide base data for simulation models. The observations also measured differences created by irrigation treatments. Dates of fruit appearance or loss were recorded from three seasons of high‐yielding crops in field experiments on a gray clay (very fine, montmorillonitic, Typic Pellustert). The interval between squaring and flowering and between flowering and boll opening (boll period) was shorter at the top of the plant than at the bottom. Fruiting branches near but not at the bottom of the plant were the longest; they had the greatest survival of fruit to maturity, the largest bolls, and therefore the greatest contribution to yield. Boll size patterns up the plant reflected leaf size profiles, with largest bolls on fruiting branches at mainstem Nodes 7 to 13. The loss of a boll did not appear to be fully compensated for by more or larger bolls on the same fruiting branch. Fruit were most likely to be shed as young squares or as young bolls: fruit on the lower portion of the plant shed more often as squares; upper fruit shed more often as young bolls.
Effects of Nitrogen Fertility on Water Potential of Irrigated Cotton
Authors: Radin J. W. , Mauney J.R. , Kerridge P.C. 
Published: July 2010

AbstractCotton (Gossypium hirsutum L.) grown in controlled environments responds to N deficiency with decreased hydraulic conductance and midday leaf water potential (Ψw). Experiments were initiated to determine whether N deficiency similarly affects plant water relations in the field. Cotton was grown for 4 yr with adequate N or a mild N deficiency. Nitrogen fertility had little effect on Ψw (determined with a pressure chamber) early in the season, but beginning in midseason the Ψw of N‐deficient plants was 0.2 to 0.4 MPa higher than that of the fertilized plants. This difference was seen both before N had affected leaf area, and after canopy closure had occurred at both N levels. Stomatal conductances and transpiration rates of recently matured sunlit leaves (determined by steady‐state porometry) remained unaffected by N. This evidence indicates that N deficiency increased plant hydraulic conductance in the field, contrary to its effect in controlled environments. However, in regressions of transpiration rate on leaf Ψw from dawn to midday, N had no consistent effects on the slopes (a putative measure of hydraulic conductance). These discrepancies have not been resolved. Nonetheless, N deficiency clearly does not decrease hydraulic conductance of cotton in the field in Arizona as it does in controlled environments.
Morphological Development of Crested and Western Wheatgrass Following Grazing
Authors: Frank A. B. 
Published: July 2010

AbstractStage of morphological development during spring growth of perennial forage grasses can be predicted reliably from accumulated growing degree‐days (GDD) (GDID), but information is lacking on the relationship between morphological development and GDD accumulated following grazing. A study was conducted in a rainout shelter at Mandan, ND during 1987 and 1988 to determine the GDD required for morphological development of initial and regrowth forage of crested wheatgrass [Agropyron desertorum (Fisch. ex. Link) Schult.] and western wheatgrass [Pascopyrum smithii Rydb, (Löve)] Crested wheatgrass was grazed twice each year and western wheatgrass three times each year by sheep (Ovis aries L.). Water was applied weekly to provide treatments receiving 50, 100, and 150% of the long term 1 April to 1 November rainfall received at Mandan ND. Plant development following the first grazing for both species was linearly related to GDD but plant development following subsequent grazing for both species was curvilinear. The deviation from linearity became greater after the first regrowth phase for both species and occurred during periods of decreasing photoperiods. Plan development for both species was similar at all three water treatments. This information should be useful for predicting stage of plant development and, when considered with other management information, would have utility in managing grazing systems utilizing several grazing cycles.
Reductions in Soybean Yield and Quality from Corn Earworm Flower Feeding
Authors: Eckel Craig S. , Bradley J. R. , Van Duyn John W. 
Published: July 2010

AbstractSoybean, Glycine max (L.) Merr., defoliation and pod feeding by corn earworm, Helicoverpa zea (Boddie), are often considered types of injury that lead to yield and quality reductions. When infestations coincide with the flowering period, however, density of H. zea larvae is higher on flowers than on other plant parts. Experiments were conducted to assess yield reductions relative to H. zea feeding on flowers, foliage, and pods. Populations of H. zea were manipulated with insecticides at two locations in 1983 and 1984 to achieve varying densities in soybean. Flower numbers, leaf area, and pod numbers were reduced in treatments with larger populations of corn earworm larvae. In addition, fewer flowers were shed from plants with large H. zea populations, and in one trial, pod shed was also decreased. Flower removal by H. zea larvae resulted in a delay in pod set. At harvest, the number of seeds per pod was reduced in three trials that had the largest H. zea populations. Seed weight was increased or decreased by H. zea injury. Injury by H. zea sometimes increased percent soybean seed protein and sometimes reduced harvestable yield. Flower feeding contributed to yield losses by delaying pod set.
Aluminum and Calcium Constraints to Continuous Crop Production in a Brazilian Amazon Oxisol
Authors: Smyth T. J. , Cravo M. S. 
Published: July 2010

AbstractAcidity constraints in Oxisols of the Amazon may entail both Al toxicity and Ca deficiency. A field study was conducted in a Xanthic Hapludox near Manaus, Brazil, to evaluate lime and Ca requirements for corn (Zea mays L.), cowpea (Vigna unguiculata L.), soybean [Glycine max (L.) Merr.], and peanut (Arachis hypogea L.) during five consecutive years. Calcitic lime was applied once at rates of 0, 0.6, 1.2, 2.3, and 4.6 t of CaCO3 equivalent per hectare. The effects of 1 t ha−1 of gypsum, applied to four crops, were evaluated with lime rates of 0, 1.2 and 2.3 t ha−1. During the two initial years, maximum yields of corn and soybean occurred with 1.2 t of lime ha−1. In subsequent years, maximum corn yields occurred to 4.6 t of lime ha−1. Liming only increased cowpea yields in the third year. Peanut yields increased with liming to the highest lime rate in the fourth and fifth year. Gypsum increased yields for all crops to which it was applied. When averaged across time gypsum increased exchangeable Ca and reduced exchangeable Al by 0.41 and 0.20 cmolc kg−1, respectively. Increased peanut shelling percent and peanut and cowpea leaf Ca concentrations with lime, gypsum, or both were indicative of improved soil Ca supply. Maximum corn and soybean yields occurred at 27% Al saturation, whereas the critical level for peanut was 54%. Regressions of relative yield for all lime and gypsum treatments on the exchangeable Ca:Al ratio gave R2 values equal to those achieved with Al or Ca saturation. Critical Ca:Al ratio values would provide a useful index to ensure that lime recommendations based on Al saturation provide an adequate Ca supply.
Effects of Previous Cropping Systems on Soil Nitrogen and Grain Sorghum Yield
Authors: Bagayoko M. , Mason S. C. , Sabata R. J. 
Published: July 2010

AbstractProducers who grow soybean [Glycine max (L.) Merr.] in 3 to and 4‐yr rotations with grain sorghum [Sorghum bicolor (L.) Moench] or other grain crops lack information about the duration of grain yield and soil mineral N benefits of soybean in crop rotations. To determine the 1‐, 2‐, and 3‐yr effects of soybean in crop rotations, an experiment with 8 yr of continuous soybean and grain sorghum, and soybean‐grain sorghum and grain sorghum‐soybean rotations combined with fertility treatments of control, N (45 kg ha−1 on soybean and 90 kg ha−1 on grain sorghum) and manure (16 Mg ha−1 dry‐matter containing 160 to 250 kg available N ha−1) was terminated in 1987. In 1988 and 1989 grain sorghum was grown on all plots without fertilizer to determine the residual effects of previous cropping system and fertilizer regime on soil mineral N, sorghum grain, and stover yield. The experiment was conducted near Mead, NE on a Sharpsburg silty clay loam soil (fine montomorillinitic, mesic, Typic Arqiudoll). Early in the 1988 season plots with soybean as the previous crop had 44 to 50 kg ha−1 more NO3 ‐N in the 150‐cm soil profile than did plots with continous grain sorghum. Early in the 1989 season, plots where soybean had been grown 2 yr previously had 17 to 23 kg ha−1 more soil NO3‐N than did continous grain sorghum plots, while plots 3 yr after soybean had only 3 to 8 kg ha−1 more soil NO3‐N. The yield of grain sorghum in the first, second, and third year following soybean was 2 to 3, 0.4 to 1.4, and 0.1 Mg ha−1, respectively, greater than the yield of continous grain sorghum. This study indicated that soybean in a crop rotation can contribute to soil NO3‐N and consequently increase sorghum grain yield for 2 yrs if fertilizer N is limiting.
Concentration Dependency and Stage of Crop Growth in Alfalfa Autotoxicity
Authors: Hegde Ramesh S. , Miller D. A. 
Published: July 2010

AbstractShoots of alfalfa (Medicago sativa L.) contain water‐soluble chemical compounds which are autotoxic, i.e., inhibit the growth of alfalfa itself. The objectives of this study were to (i) determine the inhibition threshold of the water‐soluble chemical compounds (autotoxic principle), and (ii) demonstrate that the inhibition of seed germination on early seedling growth of alfalfa is due to autotoxinic compounds from alfalfa shoots and not from microbes. A farmer must make a decision on whether or not it would be advisable to replant alfalfa based on the level of alfalfa residue still growing in the field. Laboratory and greenhouse studies were conducted to determine if autotoxicity in alfalfa due to water‐soluble compounds is concentration dependent. Filter‐sterilized and non‐filter‐sterilized shoot aqueous extracts from vegetative and reproductive stages of ‘WL‐316’ alfalfa were assayed at 20, 40, 60, and 80 g L−1 (fresh shoot weight basis) for their effect on seed germination and root and shoot elongation of seedlings of WL‐316 alfalfa in a growth chamber. Compared with the control, root length, shoot length, and germination were inhibited beyond 20 g L−1 concentration. Shoot extract from the reproductive stage was more inhibitory than from the vegetative stage under laboratory conditions. In the greenhouse, incorporation of 4‐wk‐old green herbage from vegetative stage beyond 48 shoots per square meter level resulted in severe reductions in seedling emergence and plant fresh weight per unit area. Among the several phenolic compounds assayed for their phytotoxicity on root and shoot growth of alfalfa, coumarin and transcinnamic acid at 60 ± 10 μg mL−1 were the most inhibitory. Mixtures of five or more phenolic acids were more phytotoxic than their respective individual components except in the case of trans‐cinnamic acid and coumarin. Autotoxicity in alfalfa may be caused by an interaction of many, yet uncharacterized chemical compounds present in shoots.
Yield Response of Bermudgrass and Bahiagrass to Applied Nitrogen and Overseeded Clover
Authors: Overman A. R. , Wilkinson S. R. , Evers G. W. 
Published: July 2010

AbstractModels can be used to describe yield response of grasses to applied N and other management factors. This analysis was performed to show interactions between applied N and overseeded clover on dry matter yield, and to estimate equivalent N supplied by clover. Data from three locations were used. At Watkinsville, GA both ‘Coastal’ and common bermudagrass [Cynodon dactylon (L.) Pers.] were overseeded with crimson clover (Trifolium incarnatum L.). At Eagle Lake, TX, both Coastal bermudagrass and ‘Pensacola’ bahiagrass (Paspalum notatum Flugge) were overseeded with ‘Yuchi’ arrowleaf (Trifolium vesiculosum Savi) and 'Mt. Barker* subterranean (Trifolium subterranean L.) clovers. At Jay, FL both Coastal bermudagrass and Pensacola bahiagrass were overseeded with crimson clover. The logistic model described dry matter response to applied N and contained three parameters (A, b, c). It was shown that the presence of clover affected only the b coefficient, which related to yield at zero applied N. It was also shown that overseeded clover provided equivalent N of approximately 120 kg ha−1 for bermudagrass and 90 to 220 kg ha−1 for bahiagrass. Most of the increased yield of the bermudagrass‐clover combination over bermudagrass without clover was due to the clover production; only about 25 kg ha−1 of equivalent N was carried over to the bermudagrass under conditions where top growth of clover was removed. The model allows quantitative estimates of equivalent N supplied by clover.
No‐Till Corn Production as Affected by Mulch, Potassium Placement, and Soil Exchangeable Potassium
Authors: Yibirin H. , Johnson J. W. , Eckert D. J. 
Published: July 2010

AbstractOptimizing the yield of no‐till corn (Zea mays L.) requires an understanding of corn response to K fertilization practices in no‐tillage systems. This study was conducted to determine the effects of mulch rate, K‐fertilizer placement method, and soil exchangeable K (SEK) concentration on corn grain yield, ear leaf K concentration (ELKC), and root SEK distribution in a no‐tillage system. There were five initial SEK concentrations (54, 59, 78, 95, and 122 mg K kg−1), three mulch rates (zero, normal, and double), and two methods of K‐fertilizer placement, broadcast and banded, at a rate of 46 kg K ha−1.. A Crosby silt loam soil (fine, mixed, mesic Aeric Ochraqualf) was used. Increasing mulch rate increased ELKC at all SEK concentrations and yield at SEK below 90 mg K kg−1. Increasing SEK increased yield in the zero and normal mulch treatments but not in the double mulch treatments. Banding K increased ELKC and yield only at low SEK concentrations; the effect of banding on yield was observed only in the zero mulch treatments. The lack of yield increase with banding in the mulched treatments was attributed to greater root growth in the 0‐ to 5‐cm depth, which may have allowed for more efficient use of broadcast K fertilizer. The SEK concentration decreased with depth and distance from the row in all treatments. Results indicate that the yield benefit of banding K, increasing SEK concentration, or both decreases with increasing rate of mulch.
Within‐Season Calibration of Modeled Wheat Growth Using Remote Sensing and Field Sampling
Authors: Maas Stephan J. 
Published: July 2010

AbstractWithin‐season calibration using observations of growth and phenology provides an objective means for crop simulation models to be self‐correcting. Estimating crop growth and phenology for a large number of fields by traditional ground‐based sampling methods can be undesirably time‐consuming. Certain aspects of crop growth can be estimated more quickly for a large number of fields using remote sensing. A study was conducted to compare the results of calibrating a crop simulation model using within‐season observations of leaf area index (LAI) obtained either from field sampling or remote sensing. Winter wheat (Triticum aestivum L.) yields at three locations in the U.S. Great Plains for 2 yr were modeled more accurately using remotely sensed LAI observations, than using field‐sampled LAI observations. This difference in accuracy appeared to result from the apparent ability of the remotely sensed LAI observations to better represent the photosynthetically active plant area in the crop canopy. Results of the study indicate that remote sensing may be an effective source of field observations for within‐season calibration of crop simulation models.
Nitrogen and Planting Date Effects on Low‐Protein Spring Barley
Authors: Weston Dale T. , Horsley Richard D. , Schwarz Paul B. , Goos Robert J. 
Published: July 2010

AbstractGrain protein of barley (Hordeum vulgare L.) produced for malting often is greater than the industry's acceptable standards of 135 and 130 g kg−1 for six‐rowed and two‐rowed barley, respectively. Environmental conditions such as low rainfall and high temperatures after anthesis often cause increased grain protein. This study was conducted at four dryland environments in North Dakota over 2 yr to compare the effects of N fertilization and planting date on agronomic and malt quality traits of two experimental barley genotypes inherently low in grain protein with two barley cultivars currently grown in the U.S. Midwest. Agronomic traits evaluated were grain protein, grain yield, kernel weight, and kernel plumpness. Malt quality traits evaluated were fine‐grind extract, soluble wort protein, diastatic power (DP), and ɑ‐amylase activity. Nitrogen rates ranged from 0 to 200 kg ha−1. Nitrogen significantly increased grain protein, grain yield, soluble wort N, DP, and ɑ‐amylase activity, and decreased kernel weight, kernel plumpness, and fine‐grind malt extract. Significant genotypes differences were observed for all traits. The N × genotype interaction was significant for all agronomic traits, soluble wort N, and DP. The standard cultivars had greater than the acceptable grain protein when fertilized with 150 or 200 kg N ha−1. Delaying planting significantly decreased grain yield and fine‐grind malt extract. Grain protein of the low‐protein genotypes was within the limit desired by the malting and brewing industry at all N rates and planting dates. Thus, protein levels acceptable to maltsters can be obtained for low‐protein barley genotypes when excessive N is available and growing conditions are unfavorable.
Grazing Initiation Date and Stocking Rate Effects on Pasture Productivity
Authors: Bryan William B. , Prigge Edward C. 
Published: July 2010

AbstractDate of grazing initiation in spring and stocking rate have large effects on both animal and pasture productivity. A grazing experiment with yearling steers (Bos taurus L.; average 320 kg) was conducted in the growing season of three years to compare two dates of grazing initiation (differing by 2 wk) at three stocking rates (3, 4, and 5 steers ha−1) on set‐stocked naturalized pasture in the AppalachiaUn USA. Pasture botanical composition, herbage mass and accumulation, and animal liveweight changes were measured. Early grazing initiation increased percentage grass in the pasture compared with late initiation. Crude protein concentration was higher, and acid‐ and neutral‐detergent fiber were lower in pastures on which grazing was initiated earlier. Herbage mass was >33% more at the later grazing initiation date compared with the early initiation date. Earlier grazing initiation did not affect pasture dry matter accumulation or average daily gain but animal gain per hectare was almost 20% higher with earlier grazing. Stocking rate the previous year had no effect on botanical composition or herbage mass at initiation of grazing. A verage daily gain was highest at 4 steers ha−1 (0.81 kg) and lowest at 5 steers h−1 (0.62 kg). Animal production per hectare was almost 50% greater at 4 steers ha−1 (358 kg) than at 3 steers h−1 (246 kg). We conclude that naturalized pasture in Appalachia can be grazed early without detrimental effects.
Dry Matter Partitioning and Forage Nutritive Value of Soybean Plant Components
Authors: Hintz Rodney W. , Albrecht Kenneth A. 
Published: July 2010

AbstractSoybean [Glycine max (L.) Merr.] can be a high‐quality alternative forage, but little is known about the influence of management practices on partitioning and composition of soybean plant components, and therefore on whole‐plant forage quality. Cultivar, row spacing, planting rate, and harvest maturity effects on the dry matter partitioning and nutritive value of soybean plant parts were determined in a 2‐yr field study. The cultivars Corsoy 79, Pella, and Williams 82 were grown in 20‐ and 76‐cm row spacings at planting rates of 280 000 and 890 000 seeds ha−1. Plants were harvested at R1, R3, R5, and R7 stages of development. Harvest maturity had the greatest effect on dry matter partitioning and nutritive value of soybean plant parts. The leaf dry matter fraction decreased continually as plants were harvested at later reproductive growth stages, declining from 708 g kg−1 at R1 to 168 g kg−1 at R7. The stem fraction of total plant mass increased from 292 g kg−1 at R1 to 383 g kg−1 at R5 and then declined to 283 g kg−1 at R7. The pod fraction increased from 105 g kg−1 at R5 to 549 g kg−1 at R7. As plants matured, neutral‐detergent fiber (NDF), acid‐detergent fiber (ADF), and acid‐detergent lignin (ADL) concentrations increased; crude protein (CP) concentration decreased for leaf and stem components. The greatest change occurred as plants matured from Stage R5 to R7. The pod component showed an opposite trend, with NDF, ADF, and ADL concentrations decreasing and CP concentration increasing between Stages R5 and R7. Row spacing, planting rate, and cultivar had little effect on dry matter partitioning and nutritive value of soybean plant parts.