bluuebunny/crossref_metadata_2025 huggingface dataset:
A Study of Some Biosequences and Lithosequences in the Zone of Brown Forest Soils in Northern Greece: Morphological, Physical, and Chemical Properties
Authors: Yassoglou N. J. , Nobeli Catherine , Vrahamis S. C.
Published: July 2010

Eight soils developed in northern Greece under similar climatic, topographic, and age conditions were investigated. The results indicate that significant differences in the morphological, physical, and chemical properties among the soils are due to variations in the parent material and in the vegetational cover. Soils with cambic horizons have C horizons with lower base saturation than soils with argillic horizons. The distribution of the extractable aluminum seems to be influenced by the vegetational cover and the type of the parent material of the soils. Spruce (Picea excelsa L.) has affected soil properties more intensively than scotch pine (Pinus sylvestris L.) or grasses.
Water Solubility of Zinc in a Granular Mixed Fertilizer as Affected by Zine Source and Method of Addition
Authors: Richards G. E.
Published: July 2010

Eleven various water‐soluble, slightly‐soluble, and chelated Zn compounds were incorporated into an 8‐7‐6.6 (8‐16‐8) granular mixed fertilizer in a pilot plant operation by three methods: prior to ammoniation, after ammoniation, and as a coating. Total and water‐soluble Zn was determined in the products. Most of the Zn from chelated compounds remained in a water‐soluble form for all methods of addition. Less than 10% of the Zn in soluble compounds remained water soluble when incorporated prior to ammoniation; however, the level of water‐soluble Zn was higher when incorporated after ammoniation and further improved when applied as a coating. The level of water‐soluble Zn from basic Zn compounds of low solubility was highest when they were applied as a coating. Solubility of fritted Zn was unaffected by method of incorporation into fertilizer. Soluble Zn from non‐chelated sources increased as water‐soluble P increased and also as fertilizer pH decreased.
X‐Ray Emission Spectroscopic Determination of Potassium in Sub‐Milligram Mica Samples after Sample Treatment
Authors: Weed S. B. , Philen O. D. , Leonard R. A.
Published: July 2010

Potassium in submilligram‐size samples of mica was satisfactorily determined by a thin‐specimen, X‐ray emission technique. The method utilizes Ti in the sample as an internal standard and involves the determination of the ratio KKα/TiKα. The technique provides a rapid and accurate means of determining K as a function of sample treatment, provided that the Ti content of the sample does not change.
Rubidium‐Sodium Exchange on a Weak Acid Resin as Influenced by Ionic Strength
Authors: Kunishi H. M. , Heald W. R.
Published: July 2010

Changes in the selectivity coefficient, Ks, for Na‐Rb exchange on IRC, a weak acid resin with carboxylic functional groups, were observed when the concentration of the external solution was increased from 10‐3M to 10‐1M. These ionic strength effects on Ks were interpreted in terms of an ion pair‐diffuse double layer model. Increasing Ks favoring Rb over Na with increasing ionic strength may be attributed to an increasing fraction of adsorbed ions in the ion‐pair form.
Miscible Displacement of Gases Through Soil Columns
Authors: Rolston D. E. , Kirkham Don , Nielsen D. R.
Published: July 2010

The mixing that occurs as one gas displaces another within columns of soil or glass beads was examined by using O2, He, and air for selected combinations of gaseous flow rates and column lengths. After columns were initially flushed with air or He, a second gas pumped at a constant flow rate was introduced at one end of the column. The concentration of the second gas in the gaseous effluent at the opposite end of the column was monitored during the displacement process. Elution curves (concentration of second gas versus volume of effluent) were analyzed by using a mathematical model that includes mixing by molecular diffusion, mass transport at a constant velocity, and sorption (interaction of gas with soil particle surfaces and solution of gas in water present in air‐dry soil) by a linear sorption isotherm. Although apparent diffusion coefficient values were not constant with flow velocity, the general behavior of the mixing process was adequately described by the model. Difficulties stemming from the varying gas velocity from point to point within the porous media are discussed in light of previous miscible displacement studies with liquids.
Exchange Adsorption of 3‐Amino‐1,2,4‐Triazole by an Organic Soil
Authors: Nearpass D. C.
Published: July 2010

Adsorption of 3‐amino‐1,2,4‐triazole by soil organic matter is greatly reduced by increasing pH. The main adsorped species is the aminotriazolium cation formed by protonation of the adsorbed molecule, but some direct physical adsorption of the latter also occurs. The aminotriazolium cations are adsorbed more strongly than sodium ions, and can be fully displaced by exchange with calcium ions.
Electron Microprobe Analysis of Thin Sections of Soil to Observe Loci of Cation Exchange
Authors: Hill D. E. , Sawhney B. L.
Published: July 2010

To observe the loci of cation exchange in natural soils, (16 cm3) cubes of soil with such micromorphological features as silt and clay varves, isolated clay bodies in a silty matrix, and clay and silt skins on ped surfaces, were leached repeatedly with CsCl. After the soil cubes were saturated with Cs, they were dried and impregnated with a polyester resin.

X‐ray images and Cs activity measurements, determined on thin sections with the electron microprobe, demonstrated that Cs sorbed by microstructures enriched with clay was nearly twice that of silty matrices. These observations illustrate that the loci of cation exchange are heterogeneously distributed within the undisturbed soil horizon and are influenced by micromorphological features produced by geologic and pedogenic processes.

Cesium sorbed by weathered biotite sand grains was eight times greater than by clay bodies. The greater exchange capacity of the weathered biotite was attributed to the loss of interlayer potassium and conversion to a vermiculite‐like mineral. The smaller exchange capacity of the clay was attributed to the presence of illite, chlorite, and kaolinite, of low exchange capacity, to pedogenic weathering and aluminum interlayer formation in vermiculite and to the presence of 40 to 50% pore space. Although weathered biotite sand grains constituted only 1.6% of the whole soil, they contributed about 15% to the total exchange capacity of Charlton soil.
Control of Potassium Release and Reversion Associated with Changes in Soil Moisture
Authors: Bates T. E. , Scott A. D.
Published: July 2010

The changes in exchangeable K that occur when soils are dried and rewet, and the affect of organic additives on these changes were determined with 20 soils from the North Central Region of the USA.

The release of K associated with drying was essentially eliminated by adding dextrose to the soils before drying. The use of dried samples for the determination of the exchangeable K in field‐moist soils will be limited to some extent, however, because some soils fix K when they are dried and dextrose does not prevent fixation.

In most cases, a decrease in exchangeable K occurred when air‐dry soils were rewet. A greater decrease in exchangeable K was attained with all soils when the air‐dry, rewet samples were redried in the presence of octanol. In some cases, only the reversion of K released by drying was involved, and the decrease was not enough to reduce the exchangeable K level to that in undried soil. In others, K fixation occurred and the heated soils contained less exchangeable K after treatment than they had in their field‐moist state. Nevertheless, the octanol treatment resulted in improved estimates of plant‐available K and of exchangeable K in undried soil samples over those obtainable with either air‐dry or air‐dry rewet samples.
Influence of Culture Filtrates of Soil Fungi on the Absorption of 144Ce and 90Sr by Excised Roots
Authors: Zwarun A. A. , Miller R. H. , Franklin R. E.
Published: July 2010

Culture filtrates from Aspergillus niger, Aspergillus spp., and two species of Penicillium were studied for their effect on absorption of 144Ce and 90Sr by excised roots of soybean and barley. Filtrates from both species of Asperigllus and one of the Penicillium markedly decreased the absorption of 144Ce but had little effect on 90Sr. Citric acid was found in the three active filtrates while an unidentified organic acid was found in the other. The reduced absorption of 144Ce could be duplicated by citric acid at concentrations > 10‐2M. Kojic, glucuronic, and 2‐ketogluconic acids had no effect on absorption of 144Ce, but kojic and 2‐ketogluconic acids reduced 90Sr absorption by soybean roots.
Relationships among Adsorbed Phosphate, Silica, and Hydroxyl during Drying and Rewetting of Kaolinite Suspension
Authors: Bar‐Yosef B. , Kafkafi U. , Lahav N.
Published: July 2010

Kaolinite suspensions after 1 week of equilibration with tagged phosphate solution were dried isothermally (24C) from an initial water: clay weight ratio of 24:1 to 0.89:1. At eight points along the drying process triplicate subsamples were removed and kept sealed until the final point of the drying stage was reached. The concentrations of 31P, 32P, and silica were determined in the supernatant. The equilibrium concentration of phosphate in the solution remained unchanged along the drying process. The silica concentration increased while drying, but to a lesser extent than would have occurred in the absence of the clay. The pH changed irregularly within the limits of 6.1 ± 0.4. Kaolinite at a moisture content of 0.89 ml water per 1 g clay was rewetted to the initial water content and equilibrated for seven days. Part of the air‐dried kaolinite was oven‐dried (110C) for 48 hours and then rewetted to its original moisture content. The amount of adsorbed P released into the solution when the pH increased from 6.5 to 11.0 was smaller in the oven‐dried clay than in the air‐dried sample. This is attributed to an increase in the negative charge of the surface of the oven‐dried kaolinite. Increasing the pH, the silica was readsorbed to a maximum at pH 9.2, as expected, and released at higher pH values in accordance with the negative surface charge.
Grain Yield of Maize (Zea mays L.) in Relation to Nitrogen, Phosphorus, Sulfate, Chloride, Zinc, Boron, Manganese, and Plant Population
Authors: Fuehring H. D. , Mirreh H. F. , Ahmad Nazir , Soltanpour P. N.
Published: July 2010

Excellent climatic conditions for maize (Zea mays L.) production in the Beqa'a Plain of Lebanon led to a series of eight multivariate irrigated field experiments on a calcareous clay soil typical of much of the Middle East. The objective was to determine which factors, in addition to N and P deficiencies, may become important as grain yields are increased to levels in the range of 12 to 18 tons/ha or more. Central composite, rotatable, experimental designs and regression analysis were used.

Applied N was the only variable having an appreciable first order effect and most of the yield variation was attributed to the various two and three‐factor interactions involved. Although the soil was well‐drained and the quality of the irrigation water good, amounts of applied chloride and sulfate needed to be minimized due to negative P‐Cl, P‐S, and N‐P‐S interactions when N and P were applied at necessary levels of about 300 kg/ha. Positive interactions of applied Zn with plant population and applied P with population along with the positive Zn‐B‐population and P‐B‐population interactions indicated a requirement for relatively high levels of applied P, Zn, B, and plant population. Positive response to applied Zn and B occurred up to the 90 to 180 kg/ha level indicating the need for these elements at high yield levels. However the efficiency of use was low for the application method used (somewhat dispersed band about 5 cm below the seed) and further work is needed.

The experiments were exploratory pointing the way to further investigation of nutrient balance and plant population. The micronutrient requirements of maize appear to be especially critical at very high yield levels and the detrimental effect of applied sulfate on grain yield requires further work in relation to anion balance.
One‐Degree Increments in Soil Temperatures Affect Maize Seedling Behavior
Authors: Walker John M.
Published: July 2010

One‐degree differences in soil temperatures, ranging from 12 to 35C, induced changes in the growth and nutritional behavior of maize seedlings (Zea mays L.) amounting to as much as 30 to 40% per degree. An improved system was developed to provide the precise environmental control required. The system provided for nearly isothermal control of soil temperatures even when soil and air temperatures differed by as much as 15C. The system also provided for uniform control of air temperature within ±0.7C and relative humidity within ±1% throughout the growing region in the 2 by 2.75 by 2 m growth chamber.

With each degree increase in soil temperature from 12 to 26C, total seedling dry weights were an average of 20% greater than weights at each previous soil temperature and an average of 12% smaller with each degree increase from 26 to 35C. Nutritional status, leaf lengths and numbers, stem lengths, and root numbers also were very dependent upon soil temperature. Of special interest, a soil‐temperature‐dependent disorder resembling Ca deficiency was observed in the maize shoot. Also, the uptake of B was uniquely different from that of other elements. Surprisingly, the same total uptake of B occurred regardless of the soil temperature below 21C.

The desirability of rigidly controlling soil temperature in pot experiments and the importance of minor changes in soil temperature on plant behavior have been clearly demonstrated.
Foliar and Soil Nutrients in Relation to Sugar Maple Decline
Authors: Mader Donald L. , Thompson Bruce W.
Published: July 2010

The relationship of soil fertility to decline of the sugar maple (Acer saccharum Marsh.) was studied in forest and sugarbush stands by soil studies, foliar analyses and fertilization trials. Site studies of 21 stands indicated that foliar nitrogen was low among trees and stands exhibiting crown decline symptoms and reduced growth rates. Both low and high levels of total soil N were associated with low foliar N and poor growth. Foliar Ca and Mg were closely correlated with levels in the soil.

Fertilizers were applied to three stands and their influence evaluated after one growing season by visual leaf response and foliar nutrient changes. Fertilization at the rate of 224 kg of N/ha increased the low foliar N levels in the two stands where decline was present, resulting in improved foliage color and condition.

The studies demonstrated that foliar N deficiencies are a critical factor in sugar maple decline. Deficiencies were corrected by fertilization during a drought period. Drought is believed by many to be the cause of decline. Both N availability and uptake may be restricted during drought periods.
Soil Perfusion under Controlled Conditions of Soil Moisture Content and Soil Atmospheric Composition
Authors: Wildung R. E. , Biggar J. W. , Chesters G.
Published: July 2010

A new soil perfusion system is described which allows the continuous recycling of an aqueous solution through a soil column under controlled environmental conditions. The system consists essentially of a perforated inner column for soil, jacketed by an outer column in which constant air pressure is maintained. Precise control of soil moisture content and soil atmospheric composition during perfusion is accomplished by regulation of pressure and composition of gases surrounding the soil column.
Thermo‐Osmosis Through Compacted Saturated Clay Membranes
Authors: Dirksen C.
Published: July 2010

Thermo‐osmotic permeability of saturated Na‐kaolinite decreased less rapidly with increasing compaction pressure, Pc, than did hydraulic permeability, resulting in a moderate increase of thermo‐osmotic pressure difference Γ1. At Pc = 435 kg/cm2, a hydraulic pressure gradient of 1 cm water/cm caused still twice as much flow as a thermal gradient of 1C/cm (Γ1 = 0.54 cm water/C).

For saturated Na‐bentonite at Pc = 7.0 kg/cm2, Γ1 decreased, but kT increased with increasing average temperature. Γ1 was about three times higher than that of Na‐kaolinite at Pc = 435 kg/cm2. A temperature gradient of 15C/cm was within the linear region for Na‐bentonite, but 22C/cm was not for Na‐kaolinite. All thermal flow of water occurred from the warm to the cold side and was generally less than that reported for liquid water in unsaturated soils at comparable water contents.

The apparent activation energy of thermo‐osmotic water transport in Na‐bentonite was estimated to be about 29 cal/g water; the heat of transport was more than three orders of magnitude smaller. Identification of Γ1 with the heat of transport requires application of irreversible thermodynamics, which has not been done rigorously for soil water transport.
Effects of pH on the Contributions of Organic Matter and Clay to Soil Cation Exchange Capacities
Authors: McLean E. O. , Owen Eric J.
Published: July 2010

The cation exchange capacities versus pH of 12 soils from 10 states were determined by measuring Ba adsorbed by the unlimed soils from buffered solutions adjusted from pH 2.5 to 8.0, and K adsorbed from 1.0N KCl by incrementally limed (and incubated) soils. The contributions of organic matter and clay to soil CEC at various pH's were computed by multiple regression analysis of the CEC(BaCl2) and CEC(KCl) data for whole soils. The results indicated that the method can be used satisfactorily for either type of data, and comparison of the two sets of computed data revealed that organic exchange sites which were active for adsorbing Ba from the buffer at low pH were not active for adsorbing K from unbuffered KCl in soils of comparable pH. Evidently nonexchangeable Al was involved in the latter, since it generally correlated closely with organic matter content of the soils, and the average exchangeable Al doubled when OM was destroyed with H2O2.
Sodium Hazard of Bicarbonate Irrigation Waters
Authors: Pratt P. F. , Bair F. L.
Published: July 2010

Results of a 6‐year lysimeter experiment show that the water quality value based on the precipitation index (PI) for CaCO3 satisfactorily estimated the effect of the water on the composition of saturation extracts of soil samples, except where Na precipitation occurred. Essential conditions for Na precipitation, presumably as a zeolite, were a pH above 8.6 and time for dissolution of reactants from the soil and/or formation of the product. Tree trunk diameter growth by lemon trees (Citrus limons) and evapotranspiration were linearly correlated with water quality values based on PI.
Micronutrient Availability in Three Soil Materials as Affected by Applications of Zinc, Lime, and Sulfur
Authors: Hoeft R. G. , Sorensen R. C.
Published: July 2010

Three Nebraska soil materials were treated with S, CaCO3, and ZnSO4 and incubated or cropped with corn (Zea mays L.) in the greenhouse to determine essential factors affecting micronutrient release from these soils. The type of soil material had the greatest influence on plant dry matter production and nutrient composition. The application of Zn also showed important effects, but additions of S and CaCO3 had limited effect on most variables studied. The investigation indicates that increased attention must be given to the mineralogy of soils in order to discern their micronutrient‐releasing ability for crop production.
Prairie‐Forest Transition Soils of the South Dakota Black Hills
Authors: White E. M. , Johnson J. R. , Nichols J. T.
Published: July 2010

Soils with at least weak development from prairie areas in the Black Hills Ponderosa pine forest have horizon differentiation that is more characteristic of forest than grassland soils. The lower A horizon contains more sand, but less clay and silt, and has more exchangeable hydrogen than is characteristic of prairie soils in western South Dakota. The platy or nearly structureless lower A horizons and the B horizons with reddish‐colored blocky structure are similar to those of the adjacent forested soils and probably developed under forest. Thus, the soils in the grasslands apparently were suitable for forest in the past and probably are not a factor in causing the prairie today.
Soil Factors Influencing Percolation Test Performance
Authors: Derr B. D. , Matelski R. P. , Petersen G. W.
Published: July 2010

The variability of percolation test results is influenced by a complex association of soil and environmental characteristics. Statistical evaluation of 250 sites indicated considerable percolation test rate variation of individual tests within a single site. The variability of individual tests between sites on the same soil series was generally greater than the variability of individual tests within sites. The variation between sites on different soil series was even greater.

The percent silt and coarse fragments of the subsoil were positively correlated with percolation rates, and percent clay and drainage class were negatively correlated. Factors not significantly correlated were bulk density, color value and percent sand in the subsoil, depth to bedrock, and depth classes. Variables, evaluated by analysis of variance, that showed significant relation to percolation rates were certain moist and wet subsoil consistence, grade of subsoil structure; subsoil texture, drainage classes, fragipans, parent material, slope class, and surface coarse fragments. Soil depth classes, color chromas and color values did not appear to be significantly related to percolation rates. The field designated permeability classes recorded during soil profile description, were generally lower than the determined percolation rates. Soil drainage classes were found to be closely related to percolation rates, with 82% of the moderately well, somewhat poorly, and poorly drained sites having rates slower than 2.5 cm/hour, and 76% of the 140 well‐drained sites having rates greater than 2.5 cm/hour.
Nitrogen Distribution and Accretion in an Alder Ecosystem
Authors: Voigt G. K. , Steucek G. L.
Published: July 2010

Analysis of plant and soil components of an alder (Alnus rugosa [Du Roi] Spreng.) community that had invaded the bed of an abandoned mill pond showed an average annual N accretion of about 85 kg/ha. Most (93%) of the N in the ecosystem was found in the soil and there was a strong correlation between soil moisture content and N concentration. This may have resulted in part from more favorable conditions for nodule functioning. The amount of N in the alder stand during the growing season was about equal to that contained in freshly fallen litter. About three‐fourths of the N in alder plants was found in stems and twigs but highest concentrations of N were found in leaves and nodules.
Response of Bitterbrush Seedlings to Nitrogen and Moisture on a Granitic Soil
Authors: Klemmedson J. O. , Ferguson R. B.
Published: July 2010

Greenhouse studies were conducted to explore the influence of nitrogen and moisture on seedlings of bitterbrush (Purshia tridentata [Pursh] DC.), when grown in soil from three different layers. Seedlings were grown in pots in granitic soil collected from 0–15‐, 15–40‐, and 40–90‐cm soil layers with three nitrogen (N) treatments (0, 34, and 100 kg/ha) and low and high moisture regimes. Shoot and root weights of seedlings grown in surface soils without added N greatly exceeded those for seedlings grown in soil from lower layers. Added N caused seedling yields to decline on surface soils but to increase on the 40–90‐cm soil layer. Maintenance of a high moisture regime diminished the adverse effects of added N on seedlings grown in soil from the surface layer, but improved its effectiveness on seedlings grown in lower layer soils. Shoot‐root ratios and efficiency of water use by bitterbrush differed with respect to N and soil layer treatments. In subsequent experiments, six granitic soils (including the previously tested soil) proved deficient in N for barley. However, on the same soils, bitter‐brush responded negatively or gave no response to added N. The experiments showed that yields of bitterbrush declined when N in plants reached about 2.0%.
Evaluation of Urea‐Hydrocarbon Complexes as “Slow Release” Nitrogen Carriers
Authors: Paulson K. N. , Kurtz L. T.
Published: July 2010

Several urea‐aliphatic complexes were made. The most stable of these, urea‐stearic acid complex, was found to hydrolyze slower than urea in Drummer silty clay loam, although not enough to make it useful as a “slow release” nitrogen carrier.
A Comparison of Two Methods for Determining Soil Water Diffusivity
Authors: Selim H. M. , Kirkham Don , Amemiya M.
Published: July 2010

Two methods were used concurrently to determine the soil water diffusivity from horizontal infiltration of water into a soil column. In the first (recent), water content measurements were taken at a fixed position as a function of time by using the gamma attenuation technique. In the second, water content distance distributions were determined as a function of distances from the water source at a fixed time by sectioning the same column. A comparison by the two methods of the diffusivity function for three soil materials showed that the first method is as reliable as the second. Agreement of the diffusivities obtained from the two methods is considered evidence of the validity of the unsaturated water flow equation.
Effect of the Sol‐Gel Transformation in Clay‐Water Systems on Biological Activity: II. Sodium Uptake by Corn Seedlings
Authors: Baker D. E. , Low P. F.
Published: July 2010

Homoionic Na‐ and K‐ clay were prepared from the < 2µ fraction of Wyoming bentonite. The Na‐ clay separately, or combined with the K‐clay, was mixed with water to produce clay‐water systems having different clay contents. These systems were extruded through a hypodermic needle to orient the particles within them. Thereafter, some of them were disturbed by tapping their containers on the laboratory bench. Then the following quantities were measured on all or part of them: viscosity, relative partial molar free energy, (F̄ − F̄°), of NaCl, KCl and HCl, and water tension. It was found that the viscosity, the (F̄ − F̄°) of HCl, and the water tension were decreased by disturbing the clay systems, whereas, the (F̄ − F̄°) of both NaCl and KCl were increased. The physical significance of these changes was discussed.

Samples of the Na‐ clay systems were mixed with 22Na and extruded around the radicles of corn seedlings (Zea mays L.). Then Na+ uptake was determined by analyzing the seedlings for 22Na. It was found that Na+ uptake increased curvilinearly with Na‐ clay content in the range 0–4% clay and then leveled off. In the curvilinear range, Na+ uptake was directly proportional to the (F̄ − F̄°) of NaCl. Combined samples of Na‐ and K‐ clay were also mixed with 22Na and extruded around the radicles of corn seedlings. The K‐ clay was used to maintain consistency and yet dilute the Na‐ clay enough so that the seedlings would respond to changes in the (F̄ − F̄°) of NaCl. As before, some of the systems were disturbed by tapping. It was found that Na+ uptake was greater from the disturbed than from the undisturbed systems. And since the disturbance also increased the (F̄ − F̄°) of NaCl, it was concluded that Na+ uptake depended on this quantity.
Effect of Chlorinated Aliphatic Acids on Gas and Volatile Fatty Acid Production in Anaerobic Soil
Authors: Laskowski D. A. , Broadbent F. E.
Published: July 2010

By means of gas chromatography, inhibitory effects of chlorinated acetic and propionic acids on gas and acid production by amended anaerobic soil were measured in Landlow clay receiving 0, 10, and 100 ppm monochloroacetic (MCA), dichloroacetic (DCA), trichloroacetic (TCA), and 2,2‐dichloropropionic (DCP, dalapon) acids. The data show that the chlorinated acids inhibited methane production with resultant accumulation of acetate and to a lesser extent propionate. The length of methane inhibition was correlated with chlorinated acid disappearance, varying from a few days for MCA to more than 30 days for TCA and DCP at 100 ppm. In the presence of CaCO3, DCP (100 ppm) was inhibitory for less than 12 days.

The data of these experiments indicate that use of the herbicides dalapon and TCA at concentrations approximating normal field rates probably should have no lasting adverse effects on anaerobic systems buffered near neutral pH.
A Simple Procedure for Drying Solutions for Boron Determinations by the Curcumin Method
Authors: Mulford F. R. , Martens D. C.
Published: July 2010

A procedure for drying solutions for B determinations by the curcumin procedure is described. Using polypropylene centrifuge tubes in place of quartz or porcelain containers simplifies both the drying of solutions for formation of the colored complex, rosocyanine, and redissolution of the complex. Drying samples for 15 to 19 hours in a water bath at 55 ± 3C gives consistently good results.
Water Repellency and Infiltration Resistance of Organic‐Film‐Coated Soils
Authors: Fink D. H.
Published: July 2010

Water repellency and infiltration resistance of porous soils coated with a variety of thin, organic films were examined. Water repellency was determined by measuring the effective contact angle of water resting on the soil surface and infiltration resistance was determined by measuring the breakthrough pressure, i.e., the threshold pressure required to force water into the soil pore structure of these water‐repellent soils. The effective contact angle of water on these treated soils was found to be a function of (i) the structure of the hydrophobic portion of the organic admolecules, and (ii) the proportion of soil surface covered with the organic film, but was relatively independent of soil chemical and physical properties. Effective angles as high as 150 to 160° were recorded for several types of organic materials. These included several silicone water repellents, an amine‐ and a hydroxy‐substituted phenol, and an acetic acid salt of a long‐chain fatty amine. The breakthrough pressure was directly affected by the factors that controlled the contact angle, and was inversely related to the effective pore radii of the porous, water‐repellent soils.
A Salt Sensor for Use in Saturated and Unsaturated Soils
Authors: Reicosky Donald C. , Millington R. J. , Peters D. B.
Published: July 2010

A salt sensor, suitable for use in situ in saturated and partly saturated soils, has been designed and constructed from readily available materials. The behavior of the sensor, within limits, is independent of the geometry of the surrounding medium. Under hydraulic stress, the sensor is limited to a range from 0 to −0.65 bars. Failure below −0.65 bars appeared to be due to cavitation of solution within the sensor. The response time in free solution is short and the calibration of sensors remained stable over periods of weeks.
Interaction Among Atrazine, Temperature, and Phosphorus‐Induced Zinc Deficiency in Corn (Zea mays L.)
Authors: Rudgers L. A. , Demeterio J. L. , Paulsen G. M. , Ellis R.
Published: July 2010

Corn (Zea mays L.) was grown with two levels each of P and Zn with and without atrazine in the field on recently leveled P‐ and Zn‐deficient soil and in nutrient solutions in environmental chambers. Severe Zn deficiency symptoms were exhibited by field‐grown corn receiving no Zn and were accentuated by P fertilization. Atrazine had no evident effect on deficiency development. Phosphorus and Zn concentrations in leaves, but not in grain, of field‐grown corn were increased by atrazine. In environmental chambers, corn seedling growth was decreased more by atrazine toxicity than by P or Zn nutrition. Phosphorus and Zn concentrations were increased frequently by atrazine at low but not at high growing temperatures. Atrazine had little apparent effect on P‐induced Zn deficiency development in the field or in environmental chambers.
Drainage and Nutrient Effects in a Field Lysimeter Study: II. Mineral Uptake by Corn
Authors: Lal Rattan , Taylor George S.
Published: July 2010

The mineral uptake by corn (Zea mays L.) was studied in field lysimeters for the following variables: constant water table (WT) depths, intermittent flooding, and two levels each of N and the micronutrients Zn and Cu. The WT depths. of 15 and 30 cm and intermittent flooding during early growth decreased the ear leaf concentrations of N, P, K, Zn, Cu, and B and increased the leaf concentrations of Al, Fe, Mn, and Mo. Applications of N, Zn, and Cu increased the concentrations of N, P, Zn, Cu, B, Mn, and Fe but decreased that of K. Mineral uptake under wet soil conditions was associated with reducing conditions, inhibited soil mineralization and an increase in soil pH.
Geomorphic Surfaces and Soils in the Black Creek Valley, Johnston County, North Carolina
Authors: Gamble E. E. , Daniels R. B. , Nettleton W. D.
Published: July 2010

The Black Creek Valley in the dissected upper Coastal Plain is a complex of geomorphic surfaces that ranges in age from Pliocene to Recent. Soils on the Pliocene surfaces are on the interstream divides and on old terrace remnants within the valley. They are classed as Paleudults. These soils are formed in relatively uniform sediments, have sola 2–4 m thick, little or no B horizon structure, and few clay films in the upper B horizon. Discontinuous phase plinthite is found in the middle B horizon. These soils have uniform profile characteristics, are easily mapped, and the delineations have few inclusions.

The soils on the late Pleistocene to Recent valley‐side slopes and low terraces have sola less than 1.25 m thick and are classed as Hapludults. There is much variation in A2 horizon thickness, B horizon color, and texture. This arises from the variation of the sediments outcropping on the valley sides. Further variability is caused by Recent valley‐side alluvium that has irregular distribution and unpredictable thickness. Regardless of their variability, these soils all have weak to moderate B horizon structure, common clay skins on ped faces, and no plinthite. They are best mapped as complexes because of their variability. A delineation contains many inclusions.
Numerical Taxonomy of Soils from Nine Orders by Cluster and Centroid‐Component Analyses
Authors: Cipra J. E. , Bidwell O. W. , Rohlf F. J.
Published: July 2010

Multivariate statistical procedures of numerical taxonomy were used to investigate the patterns of similarities among 59 soils. Twenty‐one morphological and laboratory characteristics of modal soil profiles from nine orders of the new classification system were used. Characters were selected to avoid high intercorrelations. Raw character values were transformed to give each character a mean of zero and variance of unity. Centroidcomponent analysis with projections of soils onto centroidcharacter axes was employed. This facilitated expression of similarities among soils in three dimensions in a manner which did not assume that clusters of soils existed. Correlation and distance matrices also were computed to obtain two estimates of the similarity of each individual to every other. Similarities among soils as indicated by these two matrices were summarized by cluster analysis. Results were displayed in phenograms yielding a system of nested clusters of soils.

The three methods of estimating and summarizing similarity relationships gave comparable results. The numerical classifications agreed, in general, with the new classification system with respect to Mollisols, Alfisols, Inceptisols, Entisols, and Spodosols. Vertisols showed little affinity for one another, Aridisols clustered with Mollisols and Alfisols, and the single Oxisol clustered with Ultisols. Ultisols showed no special affinity for other Ultisols. Numerical taxonomic methods are capable of summarizing large amounts of new data efficiently, making them a valuable soil classification tool.
Loess Distribution from a Source
Authors: Frazee C. J. , Fehrenbacher J. B. , Krumbein W. C.
Published: July 2010

Loess thickness and particle size changes along six Peoria loess traverses in Illinois and southwestern Indiana were investigated by fitting the data to various mathematical models by computer. An exponential model, a logarithmic model, a power function, and an additive exponential model developed in this study were tested. The decrease in mean particle size, which is due to changes in the coarse silt content, both windward and leeward from the source is explained best by the additive exponential model. Mean particle size changes much more rapidly near the source than afar.

Leeward of the source, two changes in the rate of loess thinning occurred. The change closest to the bluff is related to particle size differences with distance from the source. The second change is attributed to greater loess deposition in a wider zone near the source by winds from different directions. Windward of the source, no change in the rate of loess thinning due to particle size differences was observed.

Based upon the particle size and thickness data presented, the decrease in loess thickness from its source is explained best by an additive exponential model. Leeward of the source where two changes in the rate of loess thinning occur, three exponential terms are needed to accurately characterize loess thickness. The decrease in loess thickness with distance from the source which is due to the more rapid decrease in particle size near the source is defined by the first exponential term. The decrease in loess thickness associated with deposition by winds of different directions is described by the second exponential term. The third exponential term depicts the regional loess thinning due to a decrease in the number of loess particles with distance from the source. Windward of the source only two exponential terms are needed to accurately describe loess thickness because no change in the rate of loess thinning due to particle size differences was observed.
Growth Rate and Yield of Cotton as Influenced by Depth and Bulk Density of Soil Pans
Authors: Lowry F. E. , Taylor H. M. , Huck M. G.
Published: July 2010

Effects of depth and bulk density of soil pans on cotton growth and yield, oxygen concentration, and water extraction were measured. At each depth‐to‐pan treatment, final plant height and yield of seed cotton were reduced as soil bulk density or penetrometer resistance increased. Growth rate and yield were less on the 10‐cm depth‐to‐pan treatment than on the 20‐ or 30‐cm depth treatments. A restricted water supply due to limited rooting volume probably was the principal factor causing reduced yield of cotton grown on the higher strength soil pans.
Interactions of Phosphorus Availability, Mycorrhizae, and Soil Fumigation on Coniferous Seedlings
Authors: Henderson Gray S. , Stone E. L.
Published: July 2010

Factorial experiments under nursery and greenhouse conditions were used to study P uptake and growth of coniferous seedlings. Vapam, Trizone, and methyl bromide effectively eliminated mycorrhizal fungi from the rooting zone of tree seedlings and thus afforded a means of studying mycorrhizae in a relatively natural environment. Growth and P content of nonmycorrhizal seedlings grown in fumigated soil without P fertilization were less than for any other treatment; this is attributed to absence of mycorrhizae. Beinoculation with mycorrhizal roots or soil, or high rates of P fertilization without inoculation prevented the reduced P uptake and poor growth caused by fumigation alone. Fumigation followed by both inoculation and P fertilization resulted in the largest seedlings and greatest P uptake. Greater absorbing surface, together with high P concentrations, presumably accounts for the greater uptake and corresponding growth increase.
Agronomic Effectiveness of Ammonium Orthophosphate and Ammonium Polyphosphate as Measured by Ion Uptake and Yield of Corn
Authors: Dobson J. W. , Wells K. L. , Fisher C. D.
Published: July 2010

Ammonium orthophosphate (AOP) and ammonium polyphosphate (APP) were compared as P sources for corn on an acid bottomland and an upland soil, both of which tested low in available P. Determinations were made for dry matter and ion accumulation by corn plants (Zea mays L.) harvested 30 days after emergence, and for grain yield. No significant differences (p = .05) were found between AOP and APP for any of the parameters measured. All significant differences determined were due to rate of applied P. In a related study to determine the interaction of P source, Zn, and lime rate on dry matter, ion accumulation, and yield of grain, no differences were observed due to source of P. Both sources of P were equally effective on corn production for the parameters measured.
Semimicro Determination of Sulfate in Water Extracts of Soils
Authors: Nelson R. E.
Published: July 2010

Sulfate in water extracts of soils is precipitated in 2:1 acetone‐water solution by adding excess Ca(NO3)2 and HNO3 to the acid pH indicated by thymol blue. The precipitate is filtered and washed free of occluded ions by leaching with ethanol. The amount of sulfate is calculated from the Ca content (0.005–0.05 meq) in the precipitate, which is determined by EDTA titration. Since the procedure is simple and rapid, the method is suitable for routine soil analysis.
Precision in Pesticide Adsorption Measurements
Authors: Green R. E. , Yamane V. K.
Published: July 2010

The precision of solute adsorption measurements (based on change of concentration in a solution equilibrated with an adsorbent) depends upon the magnitude of the solution concentration change. Coefficients of variation for measurements of atrazine adsorption on soil were inversely related to the amount adsorbed. Such variation in precision is the consequence of the indirect method of determination rather than variable experimental technique. Unsatisfactory precision is common in adsorption measurements; improvement can sometimes be achieved by altering the soil:solution ratio to obtain larger concentration changes.
Solid State Circuitry to Activate Event Recorders Used with Drop‐Counters
Authors: Unger Paul W. , Roberson G. M.
Published: July 2010

A drop‐counting apparatus is used to determine soil moisture flow rates. A drop of water (soil solution) extracted from soil falls between two electrodes of the drop counter and initiates a series of events in the circuitry that activates the relay coil of the event recorder. The chart is marked at the time the drop passes between the electrodes.
Environment and Its Role in the Development of a Scientist
Authors: Kemper W. D.
Published: July 2010

Factors influencing the development of a scientist are discussed. The most important factors motivating a scientist to greater effort are generally those provided by fellow scientists and the people whom we serve. These factors include assurance that his objectives are worthwhile, recognition of his efforts, and the opportunity to publish the truth as he sees it and bear the consequences of his actions.

Budget, technical help, and facilities are also important factors determining his production. However, the development of an enterprising scientist cannot be prevented and may sometimes be accelerated by deficiencies in his physical environment.
Soil Development and Geomorphic Surfaces, Willamette Valley, Oregon
Authors: Parsons R. B. , Balster C. A. , Ness A. O.
Published: July 2010

Soil development in the Willamette Valley is related to a sequence of seven extensive geomorphic surfaces ranging in age from postsettlement to middle Pleistocene. The surfaces were mapped on high‐altitude aerial photographs for an area about 7,800 km2. The oldest surface associated with the present drainage system is at least 5,250‐years‐old and may be as old as 34,410 years. One soil series considered representative of each geomorphic surface was chosen to illustrate soil development on successively older surfaces. Soils on the most recent surfaces have developed only A1 horizons containing about 4% organic matter. Soils develop cambic B horizons within 550 years, whereas Bt horizons are formed within a period of 5,250 years. Base saturation progressively decreases from 100% in the Haploxerolls on the younger surfaces to less than 35% in the Haplohumults on the oldest surfaces.
Water Relations of a Profile‐Modified Slowly Permeable Soil
Authors: Unger Paul W.
Published: July 2010

A study was conducted with samples obtained from Pullman silty clay loam modified to 0 (check), 90, or 150 cm with a large ditching machine. Objectives were to determine the potential for increasing water intake, retention, and storage by profile modification, and to characterize the modified soil.

Profile modification to 90 and 150 cm effectively disrupted the slowly permeable horizon of Pullman soil. Soil bulk density and strength were significantly decreased, and soil porosity was significantly increased. Unmodified soil retained more water on a volumetric basis than modified soil at ⅓‐ and 15‐bars tension, but plant‐available water as estimated from the ⅓‐ and 15‐bar values was not altered by modification. The lower water contents of the modified soil at low tensions provided for potentially greater aeration. Water entered modified soil more rapidly than unmodified soil under field conditions.
Irrigation‐Nitrogen Studies in Asparagus and Measurement of Soil Moisture Changes by the Neutron Method
Authors: Cannell Glen H. , Takatori F. H.
Published: July 2010

Three irrigation levels controlled at 0.4, 0.8, and 2 to 5 bar soil suction were combined factorially with two N levels and two varieties of asparagus (Asparagus officinalis) in a 4‐year study. The two N treatments consisted of 112 kg N/ha and 560 kg N/ha obtained from (NH4)2SO4 and the two varieties were ‘309’ and ‘500W’. Significantly higher spear yields were obtained in the 0.8 and 2 to 5 bar irrigation treatments as compared to the 0.4 bar level. The decreased spear yields in the relatively wet treatment were attributed to the effects of lower soil temperatures in that treatment prior to and during the cutting season. Fern yields were highest in the 0.4‐bar suction treatment and decreased progressively with drier irrigation treatments. High N significantly increased both spear and fern yields and was significantly superior in efficient use of water in spear production as compared to a lower N level.

Soil moisture changes with irrigation treatments were measured with neutron equipment and the data used to determine depth of root activity, depth of wetting, and the volume of water in the soil following each irrigation. The water measured in the soil was compared to that applied. The differences ranged from ± 1.2% to 1.6% which is within the range of counting error for the neutron equipment.

Efficiency in production was calculated from water applied because this included all plots rather than only those with access tubes used for neutron measurements.