bluuebunny/crossref_metadata_2025_split huggingface dataset:
Utility of Stem Diameter Changes as Predictors of Plant Canopy Water Potential1
Authors: So H. B. , Reicosky D. C. , Taylor H. M. 
Published: July 2010

AbstractStem diameter fluctuations have been used to monitor changes in plant water potential through a dynamic method to correct for the time lag. The objective of this work was to determine whether a single day's calibration was suitable for long‐term prediction of plant water potential and if the technique was applicable for different species. Plants were grown in a growth chamber, a greenhouse, and in field plots. Changes in stem diameter were monitored continuously, using linear variable differential transformers (LVDT). Leaf water potentials were measured using the pressure‐chamber technique. When the stem diameter‐leaf water potential relationship was corrected for time lag, change in stem diameter was closely related to leaf water potential over several days. The method of deriving leaf water potentials from stem diameter fluctuations was applicable for corn (Zea mays L.) and soybean (Glycine max (L.) Merr.). Water stress caused a decrease in sensitivity for soybean. This fact indicated that the frequency of calibration needs to be increased as the plants become stressed. Changes in stem diameter are a convenient parameter for predicting plantcanopy water potential and the method does not require daily calibration.
Effects of Drought on Florunner Peanuts1
Authors: Pallas J. E. , Stansell J. R. , Koske T. J. 
Published: July 2010

AbstractDroughty conditions are implicated in causing low yields, poor grades and germination, and an increased incidence of aflatoxin in the peanut (Arachis hypogaea L.). However, very little is known as to when in the growth cycle drought is most critical. Effects of five drought treatments on peanut leaf diffusive resistance, yield, and quality characteristics were studied on rainfall‐protected plots of Tifton loamy sand, a member of the fine, loamy, siliceous, Thermic Plinthic Paleudults. Early, middle, and late drought periods of short duration (35 days) and extended early and midseason droughts (70 days) were imposed by withholding irrigation. Yield, percent sound mature kernels (SMK), germination, leaf‐water potential, and leaf diffusion resistances were measured. Under droughty conditions, leaf‐water potential was lowest during midseason when evaporative demand was greatest. Leaf diffusion resistances, however, in creased with lateness and severeness of drought, reflecting leaf age and plant‐water stress. Leaf‐water potentials of −30 bars were recorded for several treatments during midseason, and values as low as −40 bars were recorded for the 35‐day midseason drought. Although the leaf‐water potentials of control plants decreased as the season progressed, they never became lower than −12 bars. In both stressed and nonstressed plants the diffusion resistances were frequently less on the upper than on the lower surfaces of leaves. Much of the plant‐water stress that developed during drought was relieved the day after irrigation and leaf diffusion resistances also returned to near normal. Vine weight was not decreased by any 35‐day drought, but was significantly reduced by 70‐day droughts.In general, drought progressively decreased yields as duration and lateness of occurrence in the season increased. The 70‐day extended early season drought caused the greatest reduction is SMK. The late season 35‐day and extended midseason 70‐day droughts lowered subsequent germination 5 and 9% respectively. These studies validate the importance of full‐season irrigation for peanuts in the Southeast. When full‐season irrigation may not be possible because of demands on the system, scheduling irrigation the latter part of the season appears next in importance.
Loss of Nitrapyrin from Soils as Affected by pH and Temperature1
Authors: Touchton J. T. , Hoeft R. G. , Welch L. F. , Argyilan W. L. 
Published: July 2010

AbstractLittle information is available on soil characteristics that influence the persistence of nitrapyrin [2‐chloro‐6‐(trichloromethyl) pyridine] in soil. Knowledge concerning these characteristics could be helpful in determining the most effective time of nitrapyrin application and in identifying soils in which the most effective inhibition of nitrification by nitrapyrin might be expected. The objective of this study was to evaluate the effects of soil pH and temperature on the disappearance of nitrapyrin and ammonium‐N from the soil. Nitrapyrin was applied at rates of 2 and 4 ppm to three soils with pH levels adjusted to approximately 5.5, 6.3, and 6.8. In two of the three soils, the rate of nitrapyrin disappearance increased with increasing pH levels. However, nitrapyrin concentrations in the soil at the end of the 83‐day incubation period were equal among pH levels. When pH influenced nitrapyrin disappearance, recoverable nitrapyrin decreased curvilinearly with time. When pH had no apparent effect on nitrapyrin, recoverable nitrapyrin decreased linearly with time.In the temperature study, nitrapyrin and N were applied to Drummer (Typic Haplaquoll) and Cisne (Mollic Albaqualf) soils and incubated for 154 days at temperatures of 4, 13, and 21 C. Disappearance of nitrapyrin and ammonium‐N occurred at all temperatures and increased with increasing temperatures. The half life of nitrapyrin in the Cisne soil was 22 days when incubated at 4 C, and less than 7 days when incubated at 13 and 21 C. The half life of nitrapyrin in the Drummer soil was 92, 44, and 22 days, when incubated at temperatures of 4, 13, and 21 C, respectively. At all temperatures nitrapyrin was more effective in controlling loss of ammonium in the Drummer than in the Cisne soil.
Canopy Temperatures: the Usefulness and Reliability of Remote Measurements1
Authors: Hatfield J. L. 
Published: July 2010

AbstractRemote measurements of leaf temperature offer a quick means of measuring individual leaf or canopy temperatures. The spatial area measured depends on the viewing angle of the infrared thermometer. This study was designed to evaluate the measurement of leaf temperature with attached vs remote measurements for a field row crop and to determine the relationship between angular and vertical temperature measurements for the seasonal growth of durum wheat. Leaf temperatures, measured with attached thermistors and thermocouples, were compared with those remotely observed with infrared thermometers to determine the accuracy of a remote measurement of leaf temperature.Small thermistors or thermocouples were attached to the underside of a leaf to measure leaf temperature and remotely measured with a Barnes PRT‐5 infrared thermometer with 2° field of view and 10.5–12.5 μm waveband, sited on the same leaf. These data were continuously, recorded for several days. These measurements were made on selected leaves from a field grown Gloria Pink bean (Phaseolus vulgaris L.) canopy in August 1976. Agreement was good for an individual leaf when the infrared measurement and attached thermistor measured the same location on an individual leaf. When the canopies or a composite of leaves were observed with infrared thermometers held vertically about one meter above the canopy and only selected leaves were measured with attached thermistors, the agreement was less good. Correction of infrared measurements to an emissivity of 0.96 decreased the difference between the two measurements in the afternoon (1330 hours PST) but increased the difference for the predawn readings. This suggests that one simple emissivity correction would not be sufficient. When angular measured canopy temperatures were compared with vertical measurements with the infrared thermometer throughout the growing season in durum wheat (Triticum durum Desf. ‘Produra’) canopies the difference between the two angular measurements was attributed to the amount of canopy seen by the infrared thermometer. When the canopy was sparse, the difference was minimal and increased to a maximum when the cover was between 20 and 50% and then decreased as the canopy became more full. Infrared temperature measurements provide reliable and accurate measurements of leaf temperature without physical attachments to the leaf. When the canopy is less than full, care has to be exercised to observe the canopy rather than a composite of soil and plants.
A Rapid Method for Obtaining Leaf Impressions in Grasses1
Authors: Rice J. S. , Glenn E. M. , Quisenberry V. L. 
Published: July 2010

AbstractMost leaf impression methods described in the literature are time‐consuming and unsatisfactory for use on ribbed or pubescent grass leaves. We have developed a rapid method to make leaf impressions in grasses. A vinyl solution is applied to the leaf surface with a camel‐hair brush and allowed to dry. A strip of transparent tape with adversive on both sides is attached to a microscope slide. The slide is applied to the leaf with the tape in contact with the vinyl film. The other leaf surface is rubbed to insure good contact between the tape and vinyl. The impression is then slowly lifted off with the slide. After a cover slip is applied, the impression can be viewed immediately or stored for an extended period of time.
Soybean Yields in Relation to Days Between Specific Developmental Stages1
Authors: Dunphy E. J. , Hanway J. J. , Green D. E. 
Published: July 2010

AbstractEnvironment, production practices, and genetic differences are known to influence the number of days between developmental stages of soybeans [Glycine max (L.) Merr.], but the yield response to differences in days between various stages is poorly understood. Twice weekly observations were made on 10 central Iowa replicated field trials over a 3‐year period to determine the date that each plot reached several specific stages of plant development. These dates and final seed yields were utilized to investigate whether number of days between specific stages of development were associated with final seed yield. All sites were mapped as Webster silt loams (a member of the fine‐loamy, mixed noncalcareous, mesic family of typic haplaquolls). Variations among the 119 cultivars represented in the study accounted for more of the differences in days between developmental stages than did sites or years. There was no association between seed yield and number of days between any two vegetative stages of development. The length of the seed development period [days from stage R4 (pods 2 cm long at top four nodes) to R7 (pods yellowing)] was more highly correlated with seed yield than was the length of any other developmental period. Plots which initiated flowering later and matured later tended to be the highest yielding plots. Longer periods of pod development [days from stage R2 (flowers at top node) to R4] tended to be associated with lower yields. The three locations which also included fertility variables showed that differences in the P and K fertility levels utilized did not influence the number of days between any two developmental stages. These findings provide breeders with another potential selection criterion and production researchers with a better understanding of how environmental and production practice differences influence soybean yields.
Response of Onions to P Placement1
Authors: Mulkey J. R. , Albach E. L. , Dainello F. J. 
Published: July 2010

AbstractConsiderable variation in seedling size, vigor, and plant development occurs in onions (Allium cepa L.) where phosphate fertilizers are surface‐applied and incorporated prior to planting. Our objective was to determine the influence of P rates and placement techniques on the growth and development of fall‐seeded onions. During the fall of 1975 and 1977, two rates of P (21.8 and 43.6 kg/ha) were banded at planting at 0, 2.5, 5, 7.5, 10, and 15 cm directly below the seed and at 0, 2, 4, 6, and 8 cm laterally from the seed at a constant depth of 5 cm. The soil was a Aridic calciustoll, fine, mixed hyperthermic. Seedling growth and P uptake by onions were enhanced when P was applied in a band directly below the seed at a depth of 2.5 cm. Maximum yield was obtained when P was applied directly below the seed row at a depth of 2.5 to 7.5 cm. Yield was influenced more by P placement than rate of application. Maturity was effected by both depth and lateral placement of P. This experiment has shown that precise vertical and lateral placement of P must be achieved for optimum growth and development of onions.
Root Morphology and Early Development of Maize at Varying Levels of Nitrogen1
Authors: Maizlish N. A. , Fritton D. D. , Kendall W. A. 
Published: July 2010

AbstractOrganization of root growth information for maize (Zea mays L.) indicated a lack of data on the N response of make roots. Thus, the objective of this study was to quantify the morphological response of maize roots to N.Growth chamber and field studies were conducted. Field‐grown maize was sampled during the 4 weeks after emergence to evaluate differences between field and growth chamber data. Numbers of seminal roots and lengths of the seminal root system did not increase substantially after 8 days. The nodal root system increased exponentially from 1.6 m at 8 days after emergence to 21 m at 29 days after emergence. Using the slant‐board culture technique, maize plants grown in a growth chamber received 0, 21, 42, 105, or 210 ppm total N from 50% Noagland solutions. Six plants of each treatment were harvested at 3, 10, or 17 days after emergence. Total root length of maize grown at the highest N level increased exponentially from 1.7 m at 3 days after emergence to 148 m at 17 days after emergence. Root apices increased from 111 to greater than 2,900 during the same period. Primary root (axis) numbers per plant increased with increasing N, but the elongation rate of an individual axis did not respond strongly to increased N. Frequency of laterals increased slightly as N was increased, but first order lateral elongation rate increased more strongly with increasing N. Response of shoot dry weight, root dry weight, shoot to root ratios, and leaf area to N paralleled the morphological response of roots to N. It was concluded that a growth equation which incorporates a function similar to a Michaelis‐Menten equation could accurately represent root length and root initiation as a function of time and N level.
Foliar Fertilization of Soybeans: Absorption and Translocation of 15N‐Labeled Urea1
Authors: Vasilas B. L. , Legg J. O. , Wolf D. C. 
Published: July 2010

AsbtractFoliar fertilization offers a possible means of increasing soybean (Glycine max (L.) Merr.] yields, but little is known of the utilization efficiency of foliar‐applied nutrients. Field experiments were conducted in 1976 and 1977 to determine percentage recovery of foliar applied 15N‐labeled urea by soybeans and translocation of 15N within the plant. Foliar treatments containing N, P, K, S or P, K, S were applied four times during growth stages R‐5 to R‐7. Urea, potassium polyphosphate and potassium sulfate were used to supply 84 + 9 + 28 + 5 kg/ha of N + P + K + S, respectively. The P, K, S treatment was similar except that urea was excluded.In 1976, the two foliar treatments tested on the cultivar ‘Williams’ did not result in a significant increase in seed yieId over the control value of 3,294 kg/ha. In 1977, using the cultivar ‘Kent,’ the N, P, K, S treatment resulted in a significant yield increase of 1,045 kg/ha over the control value of 3,203 kg/ha. Results from the P, K, S treatment, although consistently higher than control values, were not significantly different at the 5% level in either year. Of the total 15N applied, 44 and 67% were recovered in the plants in 1976 and 1977, respectively. Approximately 94% of the recovered 15N ultimately was found in the seed. A maximum of 0.7 kg/ ha of the fertilizer N was translocated to the roots.In a separate experiment, (15NH4)2SO4 was sidedressed at the rate of 112 kg N/ha at weekly intervals to different experimental units during late R‐4 to R‐7 stages. The uptake of 15N decreased from 39 kg/ha with the first application to 19 kg/ha with the last application, but the rate of 15N uptake did not change appreciably with time. Total N in the plants was not influenced by the (15NH4)2SO4 applications. The data indicated that changes in the rate of nutrient absorption by roots during pod‐fill were minimal and unlikely to be a major factor in determining the effectiveness of foliar fertilization.
Comparison of N Fertilizers for No‐Till Corn1
Authors: Bandel V. A. , Dzienia Stanislaw , Stanford George 
Published: July 2010

AbstractLittle is known about the relative effectiveness of granular (UG) or prilled urea (UP), urea‐ammonium nitrate solutions (UAN), and ammonium nitrate (AN) when top dressed for no‐till corn. In most of the field studies reported, the N‐fertilizer used with no‐tillage has been ammonium nitrate, ammonium sulfate, or ammonium‐based mixed fertilizers. We conducted field experiments for 3 years on three moderately well‐drained Mattapex, Bertie, and Delanco silt loam soils (all Aquic Hapludults), comparing topdressed UG, UP, UAN solution (30% N), and AN at four N rates (45, 90, 135, and 180 kg/ha) on yields of continuous corn (Zea mays L.). A zero N plot was included in each of the four replicates. Yields were significantly higher from AN than from other N sources in 1978 at Forage Farm and in 1976 and 1978 at Wye Institute. Average yield from UAN exceeded that from UP and UG at Wye Institute. In 1978, when rainfall was above normal, even at the highest rate of N (180 kg/ha) total N uptake was barely sufficient to obtain maximum yields at Forage Farm and Poplar Hill and was clearly inadequate at Wye Institute. With 180 kg/ha of N applied, N%TDM when grain had reached the dough stage was about 0.9 at Wye Institute and 1.1 at the other sites. Values associated with estimated maximum yields generally exceed 1.2%. In 1978, estimated recoveries of applied N were higher from AN than from the other N sources at Wye Institute and Forage Farm.
Interaction of Planting Date and Fall Fertilization on Winter Barley Performance1
Authors: Knapp W. R. , Knapp J. S. 
Published: July 2010

AbstractWinter survival is a major limiting factor for winter barley (Hordeum vulgare L.) production in northern areas of the U.S. This field study was conducted on a Honeoye‐Lima silt loam soil (Glossoboric Hapludalf, fine loamy, mesic) to determine the effects of planting date and fall fertilization on winter survival and crop performance in the northeastern U.S. In 1975, ‘Schuyler’ barley was planted in central New York on 8 dates ranging from 21 August to 24 October. In 1976, five plantings of ‘Jefferson’ barley were made from 31 August to 14 October. On each date, treatments of 0 N and 0 P, 22 kg/ha N and 0 P, 0 N and 20 kg/ha P, and 22 kg/ha N and 20 kg/ha P were band‐applied to the soil at planting. A uniform application of 75 kg/ha K was disked into the seedbed prior to planting. At harvest, measurements were taken for grain yield, plant height, grain moisture, test weight, and components of grain yield. Grain yields were highest from early to mid‐September plantings. Winterkilling increased greatly and yields declined as planting was delayed into October. Phosphorus was necessary for best winter survival and highest grain yields. An increase in number of spikes per area was the major reason for increased yield with both P fertilization and proper planting time. Timely planting and P fertilization also increased grain test weight and hastened plant development and grain maturation. Significant interactions between planting date and fertilization were measured for grain yield, test weight, grain moisture, and spikes/m2; as planting date was delayed the need for P fertilization became greater. Nitrogen alone had no effect on barley performance when compared to no fertilizer, and N plus P produced results similar to P alone.
Double and Monocropped Wheat and Soybeans Under Different Tillage and Row Spacings1
Authors: Crabtree R. J. , Rupp R. N. 
Published: July 2010

AbstractIn wheat [Triticum aestivum (L.) Thell] producing regions with adequate frost‐free days to permit double‐cropping, water is often the most limiting factor in producing the second crop. To more fully utilize climatic resources and land after the harvest of wheat grain, a field study was conducted on a Wynona silty clay loam (Cumulic Haplaquolls) to analyze the effects of tillage and row spacings on soil water content and yields of monocropped (MC) and double‐cropped (DC) wheat and soybeans [Glycine max (L.) Merr.].Double‐cropped wheat (DCW) yielded 2,210 compared to 2,530 kg/ha for monocropped wheat (MCW). Conventional tillage double cropped soybeans (CT‐DCS) in 50‐cm rows yielded 1,610 compared to 1,460 kg/ha in 75‐cm rows. No‐tillage double‐cropped soybeans (NTDCS) in 50‐cm rows yielded 1,730 compared to 1,550 kg/ ha in 75‐cm rows. Conventional tillage monocropped soybeans (CT‐MCS) in 50‐cm rows yielded 2,010 compared to 1,880 kg/ha in 75‐cm rows.Water content in 120 cm of soil profile was not significantly affected during the soybean growing period by tillage and row spacings; however, lack of moisture in the soil‐seed environment resulted in poorer stands and lower yields for CT‐MCS in 1976. Water storage efficiency under wheat from the fully ripe stage of growth to late September averaged 28% for MCW. More grain production and more effective use of annual precipitation and soil stored water were achieved when wheat and soybeans were DC.
Development of a Model for Use in Maize Replant Decisions1
Authors: Johnson R. R. , Mulvaney D. L. 
Published: July 2010

AbstractReduced stands after planting may force maize (Zea mays L.) producers to consider the feasibility of replanting. The objective of this research was to develop guidelines for replanting decisions based on planting date, hybrid maturity class, population density, and plant distribution. Maize was planted at central and northern Illinois locations in 3 successive years. In each experiment adapted and early season hybrids were planted at three dates ranging from late April through early June. Plots were thinned to final densities of 30,890; 41,180; 51,480; and 61,780 plants/ha. The three lower densities were distributed uniformly within the row, with small gaps ranging from 0.42 to 0.85 m long, and with large gaps 1.5 m long.Adapted hybrids tended to yield more than early season hybrids when planted before 20 May, but the overall effects of hybrid maturity class were minor. Regression analysis indicated that the optimum planting date was near 6 May, and planting either 2 weeks before or after 6 May reduced yields by less than 5%. However, a rapid decrease in yield due to planting date occurred when planting was delayed past 20 May. Averaged across environments, the interaction of planting date with density and plant distribution was not significant. Before mid May the major factors to consider in replant situations are density and plant distribution within the row. After mid May, calendar date increases in importance. A model for uniformly spaced plants is presented that predicts yield on the basis of planting date and population density. Compared to uniform spacing within the row, small gaps reduced yield by an average of 1.9% while large gaps reduced yield by 5.4%.