bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of Drying Methods on Losses of Carbon, Nitrogen and Dry Matter from Alfalfa1
Authors: Mayland H. F. 
Published: July 2010

AbstractMethods of drying forage samples were examined for their influence on the total C, N, and dry matter (DM) content of ‘Ranger’ alfalfa (Medicago sativa L.). Forage samples were freeze‐dried; air‐dried in perforated paper bags and on trays; dried in perforated paper bags in mechanical convection ovens at 60, 80, and 100 C; and oven‐dried at 100 C for 90 minutes followed by drying at 60 C, or by air‐drying. All treatments were terminated after 48 hours.Losses in C and N were measured by changes in C:K and N:K ratios. The DM losses were measured by changes in K concentration. Carbon and DM were lost more readily than N by either respiratory or thermochemical processes. These losses resulted in an apparent concentration of N in all forage dried between ambient and 100 C. All treatments, when compared to freeze‐drying, resulted in losses of C and DM. The greatest loss of DM, 5.4% occurred in samples dried at 100 C. Oven‐drying at 100 C for 90 minutes followed by air‐drying caused IDM losses of only 0.2%. Significant differences in actual N content between the various drying methods were not generally observed.
Determinants of Pasture Value of Phalaris arundinacea L. vs. Bromus inermis Leyss.1
Authors: Marten G. C. , Donker J. D. 
Published: July 2010

AbstractThe objectives of this study were to determine the influence of the apparent lack of palatability of reed canarygrass on performance of grazing dairy animals and to compare quality and yielding ability of smooth bromegrass vs. reed canarygrass through measurement of gains per animal and gains per hectare when the two grasses were grazed alone under two grazing pressures.In a preliminary pasture palatability trial, dairy heifers showed a distinct preference for brome over reed canary. A 4−year pasture production study revealed, however, that average daily gains of heifers restricted to rotational grazing within only brome or reed canary did not differ (0.74 kg for each). Also reed canary produced 20% more heifer gain per hectare than brome due to greater carrying capacity.The heavier grazing pressure caused a slight but significant reduction in average daily gains per heifer, but it resulted in increases in heifer gain per hectare over the lighter grazing pressure (19% for reed canary and 16% for brome).The preference of heifers for brome over reed canary was of little or no practical significance when the two grasses were grazed individually without choice. Reed canary was obviously higher yielding and more persistent than brome, and these traits merit recommendation of reed canary for pasture situations in which a pure stand of grass on upland mineral soil is desired.
Comparative Elemental Analyses of Plant Tissue by Spark Emission and Atomic Absorption Spectroscopy
Authors: Jones J. Benton , Isaac Robert A. 
Published: July 2010

AbstractThe analyses of 91 plant tissues for their A1, Ca, Cu, Fe, K, Mg, Mn, and Zn content by direct reading emission and atomic absorption spectroscopy were comparable for most elements. Statistically significant differences were obtained for the elements K and Mg although the numerical differences were small. The variances within each laboratory were sufficiently large for A1, Ca, Cu, Fe, Mn, and Zn to mask significant differences between laboratories. Discrepancies between laboratories were observed in several plant specie samples for the elements AI, Cu, and Fe. Reproducibility by atomic absorption was better than that obtained by emission spectroscopy except for the elements A1 and Cu. Although some differences were found for certain elements and plant tissue samples, the analytical results compared favorably between the methods and laboratories.
Aluminum Tolerance of Soybean Varieties in Relation to Calcium Nutrition1
Authors: Foy C. D. , Fleming A. L. , Armiger W. H. 
Published: July 2010

AbstractDifferential aluminum tolerance of ‘Perry’ and ‘Chief’ soybean varieties, determined previously from growth on acid Bladen soil, was confirmed in nutrient solutions containing Al as the known growth‐limiting factor. Differences in Al tolerance between the two varieties were steadily increased as the Ca level of the nutrient solution was reduced from 50 to 8 to 2 ppm.Aluminum toxicity in soybeans was associated with decreases in concentrations of Ca in the tops and roots of both varieties, but this effect of Al was much more pronounced in the Al‐sensitive Chief variety than in the more tolerant Perry. Greater Al sensitivity of the Chief variety was associated with greater susceptibility to a petiole collapse symptom. This symptom was related to a lower Ca concentration in the leaves and petioles, and specifically, related to a lower Ca concentration in the small petiole zone actually showing the collapse. Soil and solution studies indicated that the Ca deficiency observed in acid Bladen soil was Al induced. Aluminum appears to interfere to different degrees in the uptake and use of Ca by these two soybean varieties. The petiole collapse appeared to be a secondary effect of Al injury, and the presence of the symptom was not required for yield reduction by Al. The fact that soybean varieties differ in Al tolerance suggests that plant breeders may be able to develop varieties that can root more effectively in acid, Al‐toxic subsoils. Varieties differing in Al tolerance also provide valuable tools for fundamental studies on the physiological nature of Al toxicity in plants. The petiole collapse symptom associated with Al sensitivity may be useful to plant breeders in screening genetic populations of soybeans for Al tolerance.
Differential Tolerance of Cotton Varieties to Excess Manganese
Authors: Foy C. D. , Fleming A. L. , Armiger W. H. 
Published: July 2010

AbstractCotton varieties adapted to various regions of the Cotton Belt of the United States showed differential leaf crinkling symptoms and growth in greenhouse pots of acid Manteo soil (pH 4.5) from Orange, Va, Subsequent experiments with soils and nutrient solutions containing variable Mn confirmed the hypothesis that the plant symptoms were due to Mn toxicity; however, other evidence indicated that Al toxicity was more important than Mn toxicity in limiting growth.Cotton varieties showing the greatest tolerance to excess Mn in soils or nutrient solutions were ‘Rex Smooth Leaf’ (Arkansas), ‘Acala 1517D’ (New Mexico), and ‘Gregg’ (Texas). Varieties showing the least tolerance were ‘Acala 4‐42’ (California) and ‘Coker 100A’ (South Carolina). Tolerance of some varieties was attributed to the fact that they or their ancestors were developed on high‐Mn soils. Greater Mn tolerance of the Rex Smooth Leaf variety appears to be due not to reduced Mn uptake but to a greater ability to tolerate a high level of Mn in its tops. Cotton varieties having greatest tolerance to Mn were not necessarily those showing greatest tolerance to Al in a previous study.
Comparison of Sulphate of Ammonia and Slow‐Release Nitrogen Fertilizers for Rice in Trinidad
Authors: Ahmad N. , Whiteman P. T. S. 
Published: July 2010

AbstractTwo slow‐release pelletted N fertilizers manufactured by Esso Engineering and Research Ltd. known as EAP 3032 (17.7% N, 21 days to release 75%) and EAP 3033 (18% N, 63 days to release 75%) were compared with (NH4)2SO4 as sources of nitrogen for the rice variety ‘Bluebelle’ in Trinidad. Nitrogen dressing from all sources was 70 kg/ha applied at transplanting. The slow release materials were buried 5 cm into the soil after transplanting while the (NH4)2SO4 was applied and cultivated into the soil just before transplanting. The effect of these treatments on yield, growth, and N uptake was estimated. EAP 3033 resulted in increased yield of 2,920 kg/ha; EAP 3032, 2,060 kg/ha; and (NH4)2SO4, 1,195 kg/ha. The response was made up by small increases in all yield components but especially panicle weight resulting from more spikelets per panicle and a higher percentage of filled grains. The fertilizers reduced the response to a top dressing of N applied 35 days after transplanting, especially the EAP 3033 treatment. The pattern of N recovery by the crop was closely related to the release of N from the fertilizers. Plants treated with (NH4)2SO4 had absorbed all of their N when they had accumulated only 50% of final dry weight. At the same stage plants treated with slow‐release materials had absorbed only half of their final N content and they continued to absorb N to much later stages in growth.
An Improved Monolith Method for Excavating and Describing Roots
Authors: Nelson W. W. , Allmaras R. R. 
Published: July 2010

AbstractA root sampling frame was constructed to excavate roots in a soil monolith 152 by 41 by 91 cm in height. The frame and monolith were moved by farm hydraulic equipment. Access to the soil monolith was provided wtih a 10‐cm‐wide trench. The total proliferation attributable to four corn (Zea mays) plants was included in the sample, permitting more precise evaluation of horizontal and vertical root proliferation. Pin insertion into the monolith and later removal after washing, and before photography of submerged roots, permitted a better quality description of root proliferation.Corn root samples obtained 39 days after planting and application of three straw mulch treatments (about 31 days after emergence) revealed significantly different patterns of root proliferation horizontally and vertically. The relative difference of root growth was greater than that of the shoot, and shoot/root ratios varied from 1.3 to 3.1.
Influence of Submerged Soil Temperature Regimes on Growth, Yield, and Nutrient Composition of Rice Plant1
Authors: Chaudhary T. N. , Ghildyal B. P. 
Published: July 2010

AbstractRice plants of a Taiwanese indica variety, ‘Taichnng (Native) 1,’ were grown in a clay loam soil for 6 weeks from seeding under normal conditions of a greenhouse and then transferred to controlled temperature water baths where cyclic soil temperatures were maintained till harvest. Water level was maintained at a depth of 5 to 7 cm above the soil surface. The temperature cycles as characterised by their maxima and minima were 22/10, 27/I5, 32/20, 37/25 and 42C/30C. The experiment was first conducted during winter months and repeated during summer months except that 22C/10C cycle was not included.Soil temperature greatly influenced vegetative and reproductive growth of the plant. Nearly similar effects of different soil temperature regimes were observed during winter and summer although the difference of about 11 or 12C in aerial temperatures existed. Highest grain yield was obtained at 32C/20C which resulted from larger number of tillers, panicles, and spikelets, lower spikelet sterility and greater hundred grain weight than at lower and higher temperatures. A dose correspondence was observed between root and shoot growth. Greater uptake of nutrients was associated with larger root system. There was a tendency for grain to be higher and straw to be lower in N, P and K concentration at 32C/20C than at lower and higher temperatures. NPK content of the grain was significantly correlated with grain yield.The direct effects of soil and water temperature on shoot growth were also probable since tiller and panicle primordia develop at the basal portion of the stems which remained submerged under soil‐water.
Effect of Potassium on the Mineral Constituents of Pearl Millet and Sudangrass1
Authors: Schneider B. A. , Clark N. A. 
Published: July 2010

AbstractThe effect of K at O and 672 kg/ha and various combinations of Ca, Mg, and K on the nitrate‐N content of pearl millet [Pennisetum typhoides (Burm.) Staph and Hubbard] and sudangrass [Sorghum sudanense (Piper) Staph] was studied. Nitrogen and P were added uniformly on all plots. Pearl millet growth was unaffected by the K treatment in Experiment I, but this treatment increased sudangrass growth. There was no significant growth response to fertility in Experiment II, however, the Ca + Mg + K treatment tended to have the tallest plants. The fertility treatments did not significantly affect the P content of pearl millet. Pearl millet accumulated much higher amounts of nitrate N than did sudangrass. All plots receiving K singly, or in combination with Ca, and/or Mg were significantly higher in nitrate N. Nitrate N was significantly decreased by addition of Mg and by Ca, but to a lesser degree. Drought conditions seemed to intensify the influence of K on increasing forage nitrate N concentrations. Regulation of Mg and K fertility may help lessen the possibility of nitrate toxicity in pearl millet and sudangrass.
Potassium Azide as a Nitrification Inhibitor1
Authors: Hughes T. D. , Welch L. F. 
Published: July 2010

AbstractThe effect of 0, 2, 4, 8, 16, and 32 ppm KN3 on nitrification in soil was studied at 30 and 10 C. At both temperatures, KN3 was an effective nitrification inhibitor. At 30 C, 75 ppm of added NH4 + disappeared in 2 weeks where no KN3 had been added as compared to 4 weeks at the 32 ppm KN3 rate. At 10 C, 4 weeks were required for the NH4+ to disappear at 0 ppm KN3, whereas more NH4+ was present after 18 weeks than initially where 32 ppm KN3 was applied. Concentrations of (NO2‐ + NO3‐)‐ N were found to be similar at all KN3 rates once the NH4+ had disappeared. This indicates that KN3 had no effect on mineralization‐immobilization relationships. The soil pH for both incubation temperatures was 6.8.The effect of 4 ppm KN3 in soil incubated at 30 C was studied at soil pH levels of 4.5, 6.0, and 7.5. The NH4‐N and (NO2‐ + NO3‐)‐N concentrations during 4 weeks incubation indicated that KN3 did not inhibit nitrification at soil pH levels of 4.5 and 6.0 but that nitrification was inhibited at pH 7.5. At 30 C, KN3 does not appear to be an effective nitrification inhibitor for soils of pH less than 6.0.
Phosphorus‐Iron and Phosphorus‐Zinc Relationships in Corn (Zea mays L.) Seedlings as Affected by Mineral Nutrition1
Authors: Adriano D. C. , Paulsen G. M. , Murphy L. S. 
Published: July 2010

AbstractThe P‐Zn and P‐Fe relationships in corn (Zea mays L.) seedlings as affected by high P levels and low and high levels of other nutrients, varied individually, were determined. With high P levels, shoot growth was increased only by high Zn, but was decreased by deficiencies of other nutrients. N and K favored P nutrition more than Fe or Zn nutrition. Ca antagonized P, Zn, and Fe, while Mg synergized P and Zn but not Fe. Similarly, Cu and Mn antagonized shoot P and Fe concentrations and had little effect on shoot Zn concentrations. The most marked interaction at high P levels was between Fe and Zn, which mutually antagonized translocation more than absorption.
Soybean Canopy Structure and Some Radiant Energy Relations1
Authors: Luxmoore R. J. , Millington R. J. , Marcellos H. 
Published: July 2010

AbstractMeasurements were made of canopy outline, leaf area index and the radiation environment of a soybean row crop at several stages of growth. The major change with time in canopy geometry occurred in the uppermost hemicylinder of leaves which increased in height and lateral spread. The proportion of energy reflected and reradiated from the top of the canopy increased during the season and this may be related to increases in both leaf area index and lateral spread of the crop.A nonlinear relationship between the incoming radiation and the energy received at a plane within the crop indicated that changes in leaf inclination during periods of high insolation gave a more open canopy.Measurements of energy in the 310‐ to 2750‐nm waveband showed that from 65 to 85% of the radiation received at a plane in the crop came from the upper hemisphere and the remainder was reflected to the under surface. Extinction coefficients, calculated for solar radiation, showed large changes with height in the canopy, indicating that the assumptions made in applying the Bouguer‐Lambert law to energy relations in a soybean canopy are not valid. Any model of the radiation relations of row crop canopies must account for energy changes in both the vertical and lateral directions.
Nitrate Accumulation in Vegetables. I. Spinach Grown in Upland Soils1
Authors: Barker A. V. , Peck N. H. , MacDonald G. E. 
Published: July 2010

AbstractThe nitrate concentrations in spinach (Spinacia oleracea L.) blades and petioles were determined for different sources and times of application of N fertilizers to a Honeoye fine sandy loam and a Lima silt loam to determine the effect of N fertilization on the concentration of nitrates in the plant parts used for consumption for food.Nitrate concentrations were determined potentiometrically, using a nitrate‐selective ion electrode, on plant samples taken at time intervals after N fertilization and at harvest stage for processing.Nitrogen fertilization substantially increased the NO3 concentrations of spinach grown in upland soils. The following observations were significant: (a) More NO3 accumulated in leaves of plants broadcast with N fertilizers before planting than if an equivalent amount of N fertilizer was supplied by sidedressing one week before harvest. (b) The N carrier was a significant factor in governing NO3 accumulation when it was applied as sidedressing.
Detection of Differences Between Means: A Monte Carlo Study of Five Pairwise Multiple Comparison Procedures1
Authors: Carmer S. G. , Swanson M. R. 
Published: July 2010

AbstractComputer simulation techniques were used to study the properties of five procedures for pairwise multiple comparisons of treatment means. Procedures studied were: (1) the ordinary least significant difference, LSD, (2) use of a preliminary F test with the least significant difference, FLSD, (3) Tukey's Significant Difference, TSD, (4) Duncan's Multiple Range Test, DMRT, and (5) a relatively new Bayesian modification of the least significant difference, BLSD. Results presented are based on simulation of 60,000 experiments involving 3, 4, 6, or 8 replicates of either 10 or 20 treatments with various patterns of homogeneity among treatment means.Observed rates of correct decisions when real differences occur among treatments, and observed rates of three types of possible errors indicated that the FLSD, DMRT, and BLSD are more appropriate for use in research than the LSD or TSD. Based on the statistical properties observed in this study a choice among the FLSD, DMRT, and BLSD is difficult; however, the FLSD may be preferred due to its familiarity to researchers and its simplicity of application.
Dryland Evaporative Flux in a Subhumid Climate: IV. Relation to Plant Water Status1
Authors: Ritchie J. T. , Jordan W. R. 
Published: July 2010

AbstractThis investigation was conducted to determine the relations between plant water status and plant evaporation rates for use in defining critical limits of soil water availability to field crops. Seasonal trends in relative water content (RWC) of grain sorghum [Sorghum bicolor (L.) Moench] were measured concurrently with evaporation rates during a prolonged drying cycle in 1969. When the available soil water supply was depleted beyond a critical threshold, called the lower limit for potential evaporation (LLE0), daily evaporation rates began to decline substantially below the level of energy available for evaporation. Before the LLE0 threshold was reached, midday leaf RWC values were approximately 0.90. Afterwards, these values declined in proportion to measured decreases in daily evaporation. Early morning RWC values did not decrease significantly until 8 days after evaporation began to decline. Leaf stomatal response to soil water deficit was evident when daylight leaf diffusion resistances changed from 2 sec/cm before the LLE0 threshold to about 25 sec/cm 10 days after the threshold was reached.These results indicate that plant water status can be used in conjunction with measured changes in soil water content to define the amount of soil water extractable by plant roots for a particular crop, soil, and climate between the maximum water‐holding capacity of the soil and the LLE0 threshold. These critical soil water parameters can be applied to predicting evaporation in two stages: (i) a freely evaporating stage when evaporation is limited by the amount of energy available for evaporation; and (ii) a falling rate stage when evaporation declines below the potential rate. An equation is proposed for predicting evaporation in the falling stage as an exponentially decreasing function of time after the LLE0 threshold is reached.
Controlling Soil Crusting with Phosphoric Acid to Enhance Seedling Emergence1
Authors: Robbins C. W. , Carter D. L. , Leggett G. E. 
Published: July 2010

AbstractObtaining adequate and uniform stands of small seeded crops is often a serious problem on soils susceptible to crusting. A study was conducted to determine if spraying dilute phosphoric acid in narrow bands along the seeded rows would increase sugar beet (Beta vulgaris L.) seedling emergence by preventing or minimizing soil crusting and provide the needed nutritional P for crop production. Dilute phosphoric acid was sprayed along rows seeded to sugar beets on a Portneuf silt loam. Several acid concentrations and P rates were applied. Stand counts were made before and after thinning, and P concentrations were measured in sugar beet petioles sampled at three dates during the growing season. Laboratory studies were conducted to determine the effects of the phosphoric acid on soil properties.Applying 69 kg P/ha as dilute phosphoric acid in liquid volumes of 650 to 1,300 liters/ha reduced crusting by increasing aggregate stability in the soil surface, increased sugar beet seedling emergence, and provided the P needed by the sugar beet crop. The acid dissolved CaCO3 and MgCO3 in the soil surface freeing Ca++ and Mg++. The cations likely reacted with PO4Ξ from the acid to form slightly soluble Ca and Mg phosphates that acted as cementing agents in soil aggregates. Using dilute phosphoric acid to reduce crusting may be equally effective for assuring satisfactory stands of other crops on calcareous soils.
Reflected Radiation from a Soybean Crop1
Authors: Blad Blaine L. , Baker Donald G. 
Published: July 2010

AbstractThe albedo, defined as the percentage of incoming solar radiation that is reflected, was measured continuously over a soybean crop [Glycine max. (L.) Merr.] during the 1968, 1969, and 1970 growing seasons at St. Paul, Minn. The study was undertaken to establish average albedo values for soybeans and to evaluate the effects of increasing crop cover on the albedo. The average daily albedo ranged from 24% to 27% with complete soybean cover. The albedo of the moist soil was approximately 10.5% with no cover and increased at the rate of about 1.3% for each 10% increase in crop cover. Because this relationship held true over the entire growing season, it should be possible to accurately estimate soybean cover from albedo measurements once the growth characteristics of a variety have been established.It was also possible during the study to examine the effects of soil moisture and lodging on the soybean albedo. It was found that with full cover the albedo decreased at low soil moisture because the soybean leaves wilted and became more vertically oriented, thereby permitting increased penetration of incoming solar radiation. Before canopy closure, particularly early in the season, low soil surface moisture caused a marked increase in albedo. Severe lodging during mid‐August 1970 caused a marked decrease in albedo.Failure to properly shield the inverted Eppley pyranometer was shown to cause an increase in the daily average albedo of as much as 7.5% because of internal reflection from the pyranometer dome.An average albedo of 25.9% was obtained for two dear days. It was noted on these days that morning albedoes were higher than evening albedoes at the same solar altitudes. This was attributed to temporarily wilted, drooping leaves, and to increased leaf flutter from stronger afternoon winds. The average daily albedo for two cloudy days was 24%.