bluuebunny/crossref_metadata_2025_split huggingface dataset:
Modeling Soybean Leaf‐Water Potentials Under Nonlimiting Soil Water Conditions1
Authors: Stanley C. D. , Kaspar T. C. , Taylor H. M. 
Published: July 2010

AbstractLeaf‐water potential measurements for plants can be valuable in evaluating plant water status because they integrate effects of crop species, plant age, soil moisture conditions, and atmospheric demand on plant water status. When soil moisture is nonlimiting, atmospheric demand controls leaf‐water potential responses. If these responses can be predicted on the basis of key atmospheric demand components, these predictions can be useful in evaluating water‐stressed studies.This study investigated the possibility of using commonly measured meteorological data (solar radiation, air temperature, pan evaporation, relative humidity, and wind speed) to statistically model diurnal leaf‐water potential response of soybeans [Glycine max (L.) Merr.] grown under nonlimiting soil moisture conditions. It also evaluated the relative contribution to the models of each of the meteorological parameters measured. Coefficients of determination for regression models for five soybean cultivars ranged from 0.86 to 0.88 when leaf‐water potentials were predicted by using solar radiation and air temperature only as input variables. No significant differences were detected among the five cultivars, so a combined overall model was developed. Model verification data were collected from a separate location. These findings provide a tool in irrigation research to test check treatments as true “no stress” treatments.
A Device for Rapid Measurement of Rate of Flow from Gated Irrigation Pipe1
Authors: Regier Cecil 
Published: July 2010

AbstractWhen irrigating with gated pipe it is desirable to adjust each gate so that all gates have equal rate of flow. Visual estimates are inaccurate, and other methods currently used are cumbersome and time consuming. A simple, accurate device (“Ettergate”) is described that gives rapid measurement of flow rate from gated irrigation pipe. The device is made from a 3.8 liter rectangular can and a 0.45 kg coffee can.
Legume Growth and Nitrogen Fixation as Affected by Plant Competition for Light and for Soil Nitrogen1
Authors: Kitamura Y. , Whitney A. S. , Guevarra A. B. 
Published: July 2010

AbstractSince the legume responses to environmental factors may be different in grass mixtures than in pure stands, a pot experiment was conducted to evaluate the effects of plant top and root competition on the growth and N fixation of Desmodium intortum, cv. ‘Greenleaf’ grown in association with Setaria anceps, cv. ‘Nandi.’ The plants were grown in deep, narrow pots which provided for ± top competition (set close together or far apart) and ± root competition (roots in same or different half sections of the pot). All treatments were grown with and without an initial application of 60 kg N/ha.Greenleaf was a better competitor for light than Nandi in spite of the taller height of Nandi. However in contrast with Nandi, Greenleaf yields and leaf areas were reduced by root competition, especially in the minus‐N treatments. There were no significant differences in acetylene reduction activity due to either N levels or competition treatment. Nodule numbers were depressed by both top and root competition at both N levels, but the plants were able to compensate to various degrees by increases in nodule size and to a greater extent by increases in acetylene reduction activity per unit of nodule weight.
Soil Acidity Tolerance of Symbiotic and Nitrogen‐Fertilized Soybeans1
Authors: Munns D. N. , Hohenberg J. S. , Righetti T. L. , Lauter D. J. 
Published: July 2010

AbstractIn soybean (Glycine max L.), unlike other legumes, poor growth in acid soil might not be due to nodulation failure. This possibility was tested by observing lime effects on nodulation, early growth, and N concentrations in symbiotic (N2‐dependent) plants as compared with control plants fertilized with NH4NO3. There were two lime ✕ N factorial trials with acid soils: a greenhouse trial in a Typic Haploxerult, with two cultivars and 13 single‐strain rhizobial inoculants; and an outdoor container trial in a Typic Hapludult, with nine cultivars and three rates of inoculation that produced large differences in nodule weight and number. The soils were high in exchangeable and soluble Al. In both trials, liming from pH 4.4 to 6.0 (aqueous paste) doubled growth, regardless of N‐source, cultivar, or Rhizobium strain or numbers; and inoculated plants were nodulated, green, and high in N even when their growth was severely acid‐affected.Symptomatic indications that soybean growth in the acid soils was limited by Al toxicity to the host plant were confirmed in solution culture experiments with pH, Al, and Ca controlled at levels resembling those found in extracts of the soil solutions. Growth was unaffected by low Ca (200 µM) or low pH (4.5), but was depressed at 30 and 65 µM Al.The data suggest that efforts to improve acid tolerance in soybean should center on plants, not rhizobia.
Cultivar and Rhizobium Strain Effects on Nitrogen Fixation and Remobilization by Soybeans1
Authors: Israel D. W. 
Published: July 2010

AbstractMaximum utilization of the N2‐fixation capability of leguminous plants such as soybean (Glycine max L. Merr.) in crop production requires an understanding of factors that control seasonal expression of N2‐fixation activity. The purposes of this investigation were to determine the seasonal N2‐fixation pattern for a determinate soybean cultivar nodulated by an efficient Rhizobium strain and the influence of determinate soybean cultivar and Rhizobium strain on the relationship between N2‐fixation capability and reproductive tissue N demand. Greenhouse experiments were conducted in a nil‐N culture system that was sterile until inoculated with the appropriate Rhizobium strain.The seasonal N2‐fixation pattern for the ‘Ransom’ cultivar nodulated by R. japonicum strain USDA 3I1b110, revealed that 65% of the total seasonal N2 fixation occurred after N began to accumulate in reproductive tissue and that N2 fixation during reproductive development and remobilization of vegetative tissue N met 83% and 17%, respectively, of the reproductive tissue N requirement.In a second experiment, ‘Davis’ and Ransom soybeans fixed over 100% more N2 during the growing season when nodulated by strain USDA 3I1b110 than when nodulated by strain USDA 3I1b31. When Ransom and Davis soybeans were nodulated by strain USDA 3I1b110, they achieved essentially the same yields of seed dry matter and seed N by expression of N2‐fixation capability at different times in the growth cycle. High N2‐fixation capability before reproductive development coupled with remobilization of vegetative tissue N was associated with the yield potential of Davis soybeans while high N2‐fixation capability during reproductive growth was associated with the yield potential of Ransom soybeans. With either cultivar, nodulation by strain 3I1b31 restricted the amount of N stored in vegetative tissue for remobilization to developing seed.
Sod‐Seeded Soybeans for Forage1
Authors: Ocumpaugh W. R. , Matches A. G. , Luedders V. D. 
Published: July 2010

AbstractThe availability of quality forage in the mid‐summer often limits livestock production in the southern U.S. Corn Belt. Soybeans [Glycine max (L.) Merr.] sod‐seeded into grass pastures may give farmers a chance to improve the quantity and quality of forage available for grazing. The objectives of this study were to examine the growth and development patterns of four soybean cultivars grown in grass sod and to determine the potential of sod‐seeded soybeans for forage. The cultivars PI 89003‐1 (Group II), ‘Williams’ (Group III), ‘Bobwhite’ (Group V), and ‘Hill’ (Group V) were seeded on 18 June into a tall fescue (Festuca arundinacea Schreb.) sod with and without paraquat (1,1'‐dimethyl‐4,4'‐bipyridinium ion) at 0.57 kg(ai)/ha. Paraquat was used in this research to suppress the tall fescue sod.Total forage (soybeans plus grass) yields ranged from 6,700 kg/ha for Hill, sprayed with paraquat, to 4,500 kg/ha for Williams unsprayed. The crude protein (CP) content at frost ranged from 15 to 18%, and the in vitro dry matter disappearance (IVDMD) averaged about 60%. Tall fescue grown alone produced 2,800 kg/ha dry matter with 50% IVDMD and 8 to 10% CP.Dry matter accumulation of soybeans was affected by paraquat and the duration of constant growth rate. During the constant growth rate phase, plots sprayed with paraquat produced about 75 kg/ha·day of dry matter, whereas unsprayed plots produced about 50 kg/ha·day. Duration of constant growth rate increased with time to maturity except for the viney‐type Bobwhite, which had a shorter constant growth rate phase than expected.Late‐maturing soybean cultivars appear better for use as a forage because they offer greater flexibility as to time of harvest, maintain higher forage quality, and generally produce more forage than early‐maturing soybeans. These results, based on a single season, indicate that soybeans can add to the quantity and quality of the forage available in tall fescue pastures.
Delayed Emergence and Temperature Influences on Cotton Seedling Vigor1
Authors: Wanjura D. F. , Minton E. B. 
Published: July 2010

AbstractQuantitative information relating the effects of delayed emergence caused by soil crusting to cotton (Gossypium hirsutum L.) seedling vigor are needed to improve the technology for stand establishment. A greenhouse study measured the effect of crusted soil (Amarillo fine sandy loam, Aridic Paleustalfs) in delaying emergence for 50, 100, and 150% of normal emergence time for constant soil temperatures of 20, 25, and 30 C. Measurements of maximum emergence, seedling survival, hypocotyl diameter, and root disease rating were used as indicators of seedling vigor. Regression analysis indicated that seedling survival and hypocotyl diameter were minimal at 26 and 24 C, respectively, and root disease rating had a maximum value at 24 C. Seedling emergence and survival were significantly reduced when emergence was delayed between 50 and 100% of the normal emergence period, but almost all increase in hypocotyl diameter occurred in the first 50% delay. Estimates of reductions in vigor for seedlings emerging through crusted soil should be possible by measuring the degree of emergence delay and/ or hypocotyl diameter
Nitrogen Fertilization Effects on Seasonal Ca, Mg, P, and K Levels of Western Wheatgrass and Green Needlegrass1
Authors: Halvorson A. D. , White L. M. 
Published: July 2010

AbstractNitrogen fertilization has been found to increase forage production of range grasses in the northern Great Plains; however, little information is available as to how N fertilization may affect the mineral composition of the forage. Our objective was to determine the effects of N fertilization on the levels of P, K, Ca, and Mg, and the grass tetany proneness of the vegetative and floral tillers of western wheatgrass (Agropyron smithii) and green needlegrass (Stipa viridula) throughout the growing season. Nitrogen fertilizer (0, 40, 80, 160, 320, and 640 kg N/ha) was applied in a completely randomized design to each grass species in a calcareous silt loam (Typic Haploboroll). Plant samples were collected on 10 and 11 sampling dates in 1973 and 1974, respectively. Nitrogen fertilization generally increased Ca, Mg, K, and ash alkalinity and generally had little effect on the P levels of the forage; however, the absolute changes caused by N fertilization were very small and of little practical significance. Except for K and P, the level of each nutrient generally increased significantly in each grass as the growing season progressed from April to October. Season or growth stage had more effect than did N fertilization on forage nutrient content. Floral tillers had lower levels of each nutrient than did the vegetative tillers. The Mg and P contents of both the floral and vegetative tillers of both grasses were often < 0.2%. Therefore, supplementation of Mg and P to grazing livestock may be required. The potential for grass tetany, according to the K/(Ca + Mg) ratio of the forage and blood serum Mg estimates, was highest during April and May for both grasses. Western wheatgrass tended to have a greater potential for causing tetany than green needlegrass early in the growing season. Time of harvest and percentage of vegetative and floral tillers can greatly affect the concentration of K, P, Mg, and Ca in the forage. In general, the earlier the harvest, the higher the nutritional value of the forage.
Weed Control in Production of Okra in Trinidad1
Authors: Brathwaite Richard A. I. 
Published: July 2010

AbstractWeed control is frequently a severe limiting factor in okra [Abelmoschus esculentus (L.) Moench] production in the Caribbean. The objective of this field investigation was to further evaluate the effectiveness of selected herbicide treatments to control weeds in okra and to determine their effects on the yield and quality of okra under rainfed conditions. The research was conducted for 3 consecutive years on River Estate loam, a fluventic eutropept, in Trinidad. Preplant herbicide treatments of benefin (N‐butyl‐N‐ethyl‐ά, ά, ά‐trifluoro‐2, 6‐dinitro‐p‐toluidine), butralin [4‐(1, 1‐dimethylethyl)‐N‐(1‐methylpropyl)‐2, 6‐dinitrobenzenamine], and trifluralin (ά, ά, ά‐trifluoro‐2, 6‐dinitro‐N, N‐dipropyl‐p‐toluidine) and preemergence herbicide treatments of benefin, butralin, DCPA (dimethyl tetrachloroterephthalate) + diphenamid (N, N‐dimethyl‐2, 2‐diphenyl‐acetamide), DCPA, diphenamid, nitrofen (2,4‐dichlorophenyl‐p‐nitrophenyl ether), and prometryn [2, 4‐bis (isopropylamino)‐6‐(methylthio)‐s‐triazine] were applied to ‘Dwarf Long Green Pod’ okra. All herbicide treatments controlled weeds during the first 28 days after treatment. At 42 days after treatment good weed control was obtained with prometryn, trifluralin, preplant benefin, and diphenamid; and acceptable weed control was obtained with preemergence benefin and DCPA. Preplant benefin and trifluralin, and premergence benefin, prometryn, and diphenamid gave fruit yields (i.e. weight and numbers) that were equivalent to those of the handweeded check and superior to those of the other treatments. None of the herbicide treatments significantly affected the grading quality, total carbohydrate, protein, fat, or moisture content of the okra fruit. Slight initial injury to okra plants was caused by prometryn, diphenamid, and DCPA + diphenamid. The DCPA alone caused some leaf distortion which later disappeared. With the exception of nitrofen, which reduced stands, no other symptoms of injury were observed. Results of this study indicate that preplant or preemergence herbicide treatments can be used effectively in okra production.
Forage Yield and Quality of Quaker Comfrey, Alfalfa, and Orchardgrass1
Authors: Hart R. H. , Thompson A. J. , Elgin J. H. , McMurtrey J. E. 
Published: July 2010

AbstractQuaker comfrey (Symphytum ✕ uplandicum Nym.) has been promoted for years as a high‐yielding proteinrich forage crop. Although considerable research has been done in other countries, almost none has been reported from the United States. Therefore, we established field trials on a Codorus silt loam (Fluvaquentic Dystrochrept) at Beltsville, Maryland and on an Archerson sandy clay loam (Aridic Argiustoll) at Cheyenne, Wyoming. At Beltsvill, three cultivars of comfrey under two cutting schedules were compared to orchardgrass (Dactylis glomerata L.) at three N rates, and to three cultivars of alfalfa ( Medicago saliva L.) alone and in mixture with orchardgrass. At Cheyenne, two cultivars of comfrey at three N rates were compared with alfalfa. Forage dry matter yield was determined at both locations; protein concentration and in vitro dry matter digestibility were determined at Beltsville, and vitamin B12 concentration was determined at Cheyenne. Comfrey yields at both locations were about half those of alfalfa or orchardgrass at the same N rate. Closer spacing of comfrey probably would have increased yield. Protein concentration of comfrey was less than that of alfalfa or orchardgrass except at very high N rates. In vitro dry matter digestibilities of comfrey, alfalfa, and orchardgrass were 37, 62, and 61%, respectively. Contrary to some reports, comfrey forage did not contain detectable amounts of vitamin B12. Moisture content of fresh comfrey averaged 85% and was consistently higher than that of alfalfa or orchardgrass. In view of its low yield and digestibility in these tests, high cost of establishment and weed control, and low palatability to some animal species, Quaker comfrey is not recommended as a forage crop.
Prediction of Boll Opening in a Cotton Crop1
Authors: Wallach Daniel , Kletter Elazar 
Published: July 2010

AbstractA number of management decisions in cotton (Gossypium hirsutum L.) production rely heavily on estimated dates of boll opening. A simple, quantitative method to predict the timing of boll opening is presented here. The algorithm is based on the assumption that all large bolls will become open bolls after a fixed number of degree‐days. The rate of large boll accumulation and the number of degree‐days from large to open boll are taken from field counts of large and open bolls if possible. Otherwise, default values are used. The algorithm was tested with data from 13 commercial, irrigated cotton fields in Israel. Predictions of subsequent boll opening, made shortly after boll opening began, gave an average error of 4.5 open bolls/m‐row. This method of predicting boll opening is practical for individual growers, since the requirements in terms of data and computing time are small.
Seasonal Drought Response of Selected Wheat Cultivars1
Authors: Sojka R. E. , Stolzy L. H. , Fischer R. A. 
Published: July 2010

AbstractThe relationship between seasonal plant water status and final yield as affected by cultivar is not well documented in wheat. In a 2‐year field experiment, plant water status measurements were used to compare the drought response of selected wheat cultivars. Yield, xylem pressure potential (ψx), adaxial leaf diffusive resistance (R5), and soil water content (θ) were monitored. Twelve cultivars of Triticum aestivum L. em Thell and T. durum Desf., and two of Tritosecale wittmack were used. Genotypes with lower seasonal ψx generally had higher percent yield reduction, when yield was expressed as a percent of irrigated controls. Water use during the observation period in the second season was similar for all droughted treatments and cultivars (about 17 cm H2O) which was less than half that of the irrigated controls (44 cm H2O). Late in the second season, ψx, decreased to as low as −47 bars in some treatments. Correlation between midday ψx and yield (absolute or percent of control) for individual cultivars were highly significant. The importance of full night ψx recovery to near zero was apparent since for three cultivars studied intensively, 80% of the yield difference between nonstressed controls and stressed treatments had already accrued when pre‐sunrise ψx decreased to −7 bars. Further reduction of predawn ψx to −38 bars was associated with only an additional 20% of the yield loss. Observations of R, proved relatively insensitive to cultivar differences in these severely arid conditions.
Germination of Kochia prostrata Seed1
Authors: Young James A. , Evans Raymond A. , Stevens Richard , Everett Richard L. 
Published: July 2010

AbstractKochia prostrata (L.) Schrad. has shown potential as a valuable forage species for Artemisia rangelands in the western United States. Stands are relatively difficult to establish by direct seeding, while transplanted plants persist and have proved adapted on numerous Sites. The effects of temperature on the germination of K. prostrata seeds was studied by determining the influence of 55 constant and alternating temperature regimes on seed germination. The constant temperatures were 0, 2, and 5‐degree increments, 5 through 40 C. Alternating temperature regimes consisted of 16 hours at each constant temperature and 8 hours daily at each higher constant temperature. The phenology of germination in relation to incubation temperature and time was studied, and three criteria for germination were developed: (a) root tip uncoiled, (b) hypocotyl arch raised, and (c) cotyledons spread. Quadratic response surfaces and estimated percent germination with confidence limits were developed for each germination criterion. Kochia prostrata seeds readily uncoiled at a wide range of moist incubation temperatures, but seedling development was very slow at low temperatures (0 to 5 C) and seedling mortality occurred at high temperatures (40 to 50 C). Raising of the hypocotyl arch was determined to be a more appropriate criterion by which to judge germination of this species because it could be recognized as actual growth rather than an indication of imbibition. By this criterion, K. prostrata seeds attained 42% germination at temperatures considered, based on field monitoring on Artemisia rangelands, to be moderate seedbed temperatures.
Salt Response of Chickpea as Influenced by N Supply1
Authors: Lauter D. J. , Munns D. N. , Clarkin K. L. 
Published: July 2010

AbstractProduction of chickpea (Cicer arietinum L.) in semiarid and coastal areas may be limited by the salt sensitivity of the chickpea symbiosis. Accordingly, this study was done to analyze effects of salt on the symbiosis by comparing the NaCl tolerance of chickpea‐specific strains of Rhizobium with tolerance of the chickpea plant grown either with combined N or dependent on symbiotic N2‐fixation. Effects of supplemental N on the salt response of symbiotic chickpea were also tested.In greenhouse sand cultures, growth of chickpea was depressed by NaCl at only 20 mM concentration unless mineral N was provided. With no added NaCl 22 strains of rhizobia were all effective, producing plant yields comparable with NH4NO3 control treatments; but with NaCl added at 75 mM only 1 strain did significantly better than controls with no N or inoculum. Poor symbiotic performance was not due to salt limitation of growth of rhizobia. Rhizobial growth rates determined by viable counts in yeast mannitol medium were unaffected by NaCl at 120 mM and only moderately depressed by 250 mM.Effects of supplemental N were studied in a solution culture experiment with four levels of NaCl (0, 15, 23, and 31 mM) combined factorially with four different N treatments: NH4NO3 absent, present continuously, present only during the first 31 days, or present only after onset of vigorous fixation at 31 days. The growth of both N‐fertilized and symbiotic plants was inhibited by salt. Ammonium nitrate moderated salt stress most strongly during the later period of growth (after 31 days). Growth inhibition of N‐fertilized plants was associated with excess Cl accumulation in shoots, which occurred regardless of N treatment. Additional effects could account for the greater inhibition in symbiotic plants. Salt delayed nodulation, and N‐treated plants showed greater retention of Na in roots and lower concentrations of Na in shoots than completely symbiotic plantsThe data indicate a clear need for greater salt tolerance in chickpea. And since the nature of the salt response changed markedly with N‐source, selection of cultivars and testing of management procedures should be done with both N‐fertilized and symbiotic plants.