bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of Moisture on Erodibility of Soil by Wind
Authors: Chepil W. S.
Published: July 2010

This study was undertaken to determine the general influence and the specific quantities of moisture that soils must have to resist wind.

Erodibility by wind was about the same for soil that was oven‐dried or air‐dried in sun or in shade when moisture did not exceed one‐third of the 15‐atmosphere percentage. Beyond this range of moisture a distinct decrease in erodibility was manifested. Erodibility decreased rather slowly at first, then more rapidly with each successive increment of moisture added, reaching zero, on the average, at about 15‐atmosphere percentage. Increasing the moisture even slightly above the 15‐atmosphere percentage required a relatively great increase in wind velocity to produce movement of soil.

It was shown that erodibility by wind is a function of the cohesive force of adsorbed water films surrounding the soil particles. Equations were derived indicating the relationships between cohesive force due to adsorbed water films, quantity of adsorbed water, and erodibility by wind.
Soil Moisture Distribution on Irrigated Corn Plots
Authors: Dreibelbis F. R. , Youker R. E.
Published: July 2010

An account of the soil‐moisture distribution obtained by fiberglas‐gypsum blocks on irrigated plots is presented as an aid in evaluating the needs of water for irrigation on field corn and sweet corn in Southeastern Ohio. Soil moisture depletion was determined from moisture changes in the Keene silt loam and presented as total depletion in the 0 to 7‐, 0 to 10‐, 0 to 12‐, 0 to 14‐, and 0 to 18‐inch depths on sweet corn for various periods during the growing season in 1954. The data for 1954 indicate that on this soil type the 0 to 7‐inch depth would suffice as a criterion for irrigation requirements up to July 14, and the 0 to 12‐inch depth from July 15 to Sept. 17.

A summary of the data to evaluate the quantitative needs of water for irrigation purposes is presented for the Keene and Muskingum soils. Data on the moisture content at saturation, at field capacity, and at the wilting point are given in inches water for the 0 to 7‐, 0 to 10‐, 0 to 12‐, 0 to 14‐, 0 to 18‐, and 0 to 24‐inch soil depths together with the amount of water necessary to raise the moisture content to field capacity from the ½ available water level. From this level in the 0 to 24‐inch depth on the Keene silt loam, 2.76 inches water are needed to raise the moisture content to field capacity, while 2.40 inches are required on the Muskingum silt loam. In the 0 to 7‐inch depths, the values are 0.81 and 0.73 inches respectively for the same soil types.

Additional data obtained on field corn plots in 1953 are also presented as a contrast to those obtained on sweet corn in 1954. Daily depletion rates were lower on the latter.
Anomalies in Capillary Intake as Explained by Capillary Rise Experiments
Authors: Swartzendruber Dale
Published: July 2010

In an earlier study of soil structure, an attempt was made to utilize as a soil structure index, the proportionality constant in the square‐root‐of‐time equation of horizontal capillary flow. In the present paper, anomalous variations of this constant—the capillary absorption coefficient—are considered in greater detail.

As a starting point, the movement of the meniscus in a single round capillary tube was assumed amenable to treatment on the basis of Poiseuille's law. Using data from the literature, it was found that there is validity in the Poiseuille analysis. However, quantitiative agreement with the experiments depended somewhat on the conductivity K of the capillary tube.

The Poiseuille analysis was then utilized in a theoretical treatment of the capillary absorption coefficient, assuming an idealized soil model consisting of parallel, non‐interconnected capillary tubes. From the intersection behavior of capillary rise curves, it was found possible to predict within limits the behavior of the capillary absorption coefficient as affected by changes in pore radius, surface tension, wetting angle, and viscosity.

Experimental curves of capillary rise versus time were then obtained for the soils of the previous structure study for which values of capillary absorption coefficient had already been measured. The observed behavior of the coefficient, especially when a large variation was induced in it by a given structure treatment, was found to be consistent with the behavior predicted on the basis of capillary rise curves.

The favorable qualitative comparisons of the capillary tube theory with the experimental data for the soils tested, suggest that the theory can be refined for determining more simply the now difficulty determinable soil physical property—the wetting angle.
The Effect of Green and Stable Manure on the Yield of Crops and on the Physical Condition of a Tappan‐Parkhill Loam Soil
Authors: Guttay J. R. , Cook R. L. , Erickson A. E.
Published: July 2010

The effect of sweet clover‐green manure and stable manure on the yields of grain and row crops have been studied since 1936. The treatments include the application of these manures every 2, 4, and 6 years. Sweet clover‐green manure had a more beneficial effect on the yield of crops than did stable manure. The greatest effects of both manures on crop yields occurred where the manures were applied every 2 years. In the 4‐ and 6‐year treatments, marked beneficial effects were noted immediately following, or 1 year after the application of the manures, with much less or no benefit occurring thereafter until reapplication.

The effects of these treatments on the physical condition of the soil have been studied for 2 years. Granulation of the soil was enhanced by the 2‐year treatments. The effects of the treatments on the soil physical condition cannot be completely evaluated until a 6‐year study is completed.
Crop Response to Different Soil Fertility Levels in a 5 by 5 by 5 by 2 Factorial Experiment: II. Peanuts
Authors: Robertson W. K. , Hutton C. E. , Hanson W. D.
Published: July 2010

Four years' data are reported from a 5 by 5 by 5 by 2 experiment in which nitrogen, phosphorus, potassium and lime respectively, were the variables. The experiment was conducted on Red Bay fine sandy loam in west Florida.

No response to nitrogen was obtained.

There was a negative response to potash every year when more than 15 pounds of K2O per acre as potassium chloride were applied. The level of exchangeable potassium in the soil did not seem to be responsible for the negative response. Ninety pounds of exchangeable potassium per acre was adequate for maximum yields. The lack of response to potassium may have been associated either with the application of the fertilizer potassium in the peanut row or with increasing rates of phosphorus applied as superphosphate. Since high rates of phosphorus are necessary for maximum yields of other crops grown in rotation with peanuts, excess potassium, equivalent to that removed by the peanuts, probably should be applied to the other crops in the rotation.

There was a significant yield response to phosphorus every year. When the soil was adequate limed, maximum yields were obtained when the soil contained 45 pounds per acre of P2O5 extractable with 0.002N H2SO4 buffered at pH 3 with (NH4)2SO4 or 110 pounds per acre of P2O5 extractable with 0.03 N NH4F in 0.1 N HCl; 10 of extractant to 1 of soil.

Calcium gave significant yield responses three out of four years. Three tons per acre of dolomitic lime were better than one. One ton per acre of lime raised the pH from 5.3 to 5.6 and the exchangeable calcium from 300 to 500 pounds per acre of Ca approximately. When 3 tons per acre of lime were applied, the pH was 6.2 and the exchangeable Ca 850 pounds per acre.

Phosphorus interacted with lime. Less fertilizer phosphorus was necessary to give maximum yields on limed than unlimed soil.
Chlorine and Other Constituents in Relation to Tobacco Leaf‐Burn
Authors: Myhre D. L. , Attoe O. J. , Ogden W. B.
Published: July 2010

A study was made to evaluate the influence of chlorine and other constituents on tobacco leaf‐burn (capacity to hold fire when ignited). Samples of tobacco plants and soil at different depths were taken from 33 fields located in the 2 tobacco growing districts in Wisconsin in 1952, and the data concerning chemical composition and leaf‐burn were subjected to statistical analyses. The amount of chlorine taken up by the crops was most closely correlated (r = 0.79) with that found in the 0 to 12‐inch layer of soil. On the average, about ½ of the chlorine found in this layer was taken up by the crops. A highly significant coefficient of multiple correlation, R = 0.80, was found for the relation between log leaf‐burn and the contents of chlorine, sulfur, nitrogen, and potassium of the tobacco leaves. A comparison of the standard coefficients indicated that potassium is about 1.2 times more beneficial to leaf‐burn than either chlorine or nitrogen is detrimental, and about 2.4 times as beneficial as sulfur is deterimental.
Transect from Lake Tahoe, California, to the Pacific Ocean Showing Relationship Between Soils, Physiographic Position, Geology, Climate, Natural Vegetation, and Land Use
Authors: Storie R. Earl , Brown Lloyd N.
Published: July 2010

This transect starts on Highway No. 40, near the crest of the Sierra Nevada Mountains, in an area of pine and fir timber. At the beginning of the transect are granitic upland soils of the Holland series; following these are red upland soils of the Aiken series, derived from basic igneous rocks, and next, at a lower elevation, the reddish, grass‐covered Auburn soils. The higher terrace lands of the eastern Sacramento Valley are composed of the cobbly‐hardpan Redding soils, and the gravelly claypan Corning soils; on the lower terraces, the red‐iron hardpan San Joaquin soils with the recent and young alluvial soils of the Columbia and Sacramento series along the Sacramento River; and on the wet‐side alluvial fan, soils dominated by the Yolo series in the vicinity of Davis. Other noncalcic Brown valley, terrace, and upland soils are encountered west of Davis. The western Coast range of higher rainfall gives rise to the lithosolic Maymen series, and the Hugo series having a Douglasfir and redwood cover. The ocean side of the Coast Range, where there is lower rainfall, is represented by the Cayucos and Rohnerville soils having Prairie‐like characteristics.
A Chlorite‐Like Mineral in Indiana Soils
Authors: Klages M. G. , White J. L.
Published: July 2010

A clay mineral with basal spacing of approximately 14Å is a constituent of many Indiana soils. The properties of a sample of this mineral separated from Crosby silt loam were studied.

During the weathering of the soil profile, the pH decreased and the 14Å mineral replaced illite as the dominant clay mineral. In similar size fractions of clay, the potassium content decreased from the C to the A horizon, while the cation‐exchange capacity remained practically unchanged.

X‐ray diffraction and other procedures were used to determine the properties of the 14Å mineral and the effect of various treatments on these properties. Many of its characteristics were found to be similar to those reported for dioctahedral vermiculite. Several of the reactions suggested positively charged, partially hydrated aluminum hydroxide rather than hydrated exchangeable aluminum ions as the interlaying material.

It was concluded that during weathering of illite, aluminum can replace potassium between the clay plates. The form of this interlayer aluminum is probably influenced by soil pH. A suggested general formula is:
urn:x-wiley:03615995:saj2sssaj195703615995002100010005x:equation:saj2sssaj195703615995002100010005x-math-0001 where x varies with soil pH. Dioctahedral vermiculite and dioctahedral chlorite could thus form a continuous series.
Replaceability of Ammonium Fixed in Clay Minerals as Influenced by Ammonium or Potassium in the Extracting Solution
Authors: Hanway J. J. , Scott A. D. , Stanford G.
Published: July 2010

Fixed NH4 in vermiculite and bentonite was completely released by distillation in NaOH solutions. Small amounts of K in the solutions, however, blocked this release of NH4. If the amount of K was in excess of 2 K ions per 100 Na ions, no fixed NH4 was released from vermiculite. With smaller amounts of K present, the amount of fixed NH4 released decreased as the K/Na ratio in solution was increased. In an equilibrium NaCl extraction, small amounts of either fixable ion, NH4 or K, in the solution prevented the release of fixed NH4. There was no blocking from the NH4 in the NaOH distillations since it was lost from the alkaline systems. In the salt solutions, NH4 was more effective than K in blocking the release of fixed NH4. The blocking effect of a gixen fixable/nonfixable ion ratio in the neutral salt solutions increased as the amount of salt extractant per gram of mineral was increased. This is due to the preferential adsorption of the fixable cations. Higher K/Na ratios were required to block the release of fixed NH4 in neutral salt solutions than in alkaline solutions. Ten K ions per 100 Na ions in NaCl were not as effective as 2 K ions per 100 Na ions in NaOH. Higher K/Na or NH4/Na ratios were required to block the release of fixed NH4 from bentonite than from vermiculite. The NH4/Na ratio required to completely prevent the release of fixed NH4 from bentonite by NaCl was 0.04 as compared to 0.02 for vermiculite.
Effect of Douglas‐Fir Sawdust Mulches and Incorporations on Soil Microbial Activities and Plant Growth
Authors: Bollen W. B. , Lu K. C.
Published: July 2010

Sawdust and other wood wastes applied to soil may retard plant growth by inducing nitrogen deficiency but these effects with Douglas‐fir are less pronounced than with many other residues of wide C:N ratio. While Douglas‐fir wood is extremely low in nitrogen it is low also in available carbon. The predominating lignin‐cellulose complex is resistant and only slowly metabolized, enabling a minimum amount of nitrogen, repartitioned among successive crops of microbes, to suffice for long‐continued decomposition.

Sawdust showed no direct toxicity and had little effect on soil pH. Resins and other extractives were readily decomposed. Apparent decomposition percentages based on 50 days CO2 production without added available nitrogen in soil respiration experiments were: for dextrose 60, wheat straw 48, red alder 40, ponderosa pine 33, western red cedar 33, Douglas‐fir 30, pitch 30, western hemlock 27, bark 26, and lignin 6%, respectively. Although added nitrogen fertilizer hastened decomposition of organic matter having wide C:N ratio, it commonly depressed cumulative CO2 evolution in soil respiration.

Greenhouse and field studies indicate that to avoid induced nitrogen deficiency 5 to 10 pounds of nitrogen per ton of sawdust are generally sufficient during the first year; nitrogen additions the following 2 or 3 years may be successively halved. Douglas‐fir sawdust without added nitrogen often causes no retardation and in some cases significant increases of certain crops such as sunflowers and strawberries. Corn appeared much more sensitive to nitrogen deficiency. All wood wastes and cereal straws at 100 tons per acre have been found to depress plant growth unless nitrogen is added.
Residual Effects of Various Phosphates as Measured by Yields, P32 Uptake, and Extractable Phosphorus
Authors: Ensminger L. E. , Pearson R. W.
Published: July 2010

In 1930 an experiment was started on a Decatur silt loam and on a Greenville fine sandy loam to compare the effectiveness of different sources of phosphorus for crops grown in a rotation of corn and cotton with vetch. At the end of 16 years, phosphate applications were discontinued in order to study residual effects on yields. In 1950 and 1951, tagged superphosphate was applied to all treatments and available phosphorus, based on P32 uptake, was calculated and expressed as A values.

Yield data from both locations show that all sources had considerable residual effects. For any particular source, the residual effect was in proportion to the amounts that had been added. Basic slag gave the greatest residual effect on the Decatur soil as measured by vetch and cotton yields. It also gave the greatest residual effects on the Greenville soil as measured by cotton yields. Tricalcium phosphate and raw phosphate showed a much greater residual effect, as indicated by vetch yields, in the Greenville soil than in the Decatur soil.

A values show that all sources had considerable residual effects as measured by radiophosphorus uptake. The A values for basic slag at both locations were larger than for an equivalent amount of any other source. For the Greenville soil, A values show that superphosphate had a greater residual availability than rock phosphate applied at twice the rate of P2O5. However, A values on the Decatur soil indicate that rock phosphate had about the same residual availability as superphosphate applied at an equivalent rate of P2O5. For any particular source, A values were in proportion to the amounts which had been added.

Yield data for the first 4 years of the residual period show only a very general relationship with A values when all sources are considered together. However, correlation coefficients show a fairly close relationship between yields and A values in most cases when the analysis is limited to rates of one source.

Extractable phosphorus data show that phosphate applications resulted in phosphorus accumulation and that the amount accumulated was proportional to the rate of application.
The Effect of Soil Potassium Levels on Yield, Lodging, and Mineral Composition of Corn
Authors: Boswell Fred C. , Parks W. L.
Published: July 2010

Five corn hybrids (three single crosses and two double crosses) were grown on a soil low in exchangeable potassium. Four potassium fertility levels were used. K, Ca, Mg, and P were determined on leaf samples collected periodically throughout the growing season. Root lodging and stalk breakage were also determined periodically. A significant yield increase from the first increment of K2O was obtained, but no further increase was obtained from additional increments. Significant yield differences among corn hybrids were obtained. Potassium fertilization significantly decreased both root lodging and stalk breakage. The corn hybrids were found to differ significantly in their root lodging and stalk breakage characteristics.

The potassium content of the plant increased with increased rates of potassium fertilization. The maximum potassium content of the plant was observed during the early stages of plant growth and the potassium content decreased percentagewise as the plant neared maturity. The calcium and magnesium contents of the leaf tissue were generally inversely related to the potassium content of the plant. The phosphorus content was unaffected by the potassium fertility treatments. The milliequivalents of total cations (K, Ca, Mg) per 100 g. of over‐dry tissue (1) decreased at a given stage of plant growth as the rate of potash fertilization increased, (2) increased with age of plant at the lower potassium levels, and (3) remained essentially constant throughout the life of the plant at the highest potassium level. The sum of the percent K, Ca, and Mg content of the plant was essentially a constant at all stages of growth.
Ridged Rows and Winter Cover Crops in Tobacco Production
Authors: Britt C. S. , Slater C. S.
Published: July 2010

Ridged rows and winter cover crops were used to control erosion and promote good tilth in 1‐year tobacco rotations. Studies conducted over a 5‐year period comparing flat cultivation versus ridged rows showed that tobacco yields were increased substantially by ridging in wet years. In dry years, yields on ridged and flat plots were essentially the same.

Winter cover crops and their management affected both the yield and quality of the succeeding tobacco crop. Ryegrass alone reduced yield and vetch alone lowered quality. Highest yields and quality of tobacco followed mixed cover crops of rye and vetch or ryegrass and vetch.

Late turning of the mixed cover crops was better than early turning. Aside from supplying more organic residues to the soil, late turning promoted the larger yield of tobacco, of as good a quality as early turning.
Use of Acid‐Fluoride Solutions for the Extraction of Available Phosphorus in Calcareous Soils and in Soils to Which Rock Phosphate Has Been Added
Authors: Smith F. W. , Ellis B. G. , Grava J.
Published: July 2010

In the chemical measurement of “available” phosphorus in calcareous soils from western Kansas, it was found that a method involving use of a solution of 0.025N HCl and 0.03N NH4F worked very well. It was necessary to use a large volume of solution to effect accurate measurement of available phosphorus. Neither dilute acid alone nor 0.1N HCl plus 0.03N NH4F proved satisfactory. Use of 0.5M NaHCO3 buffered at pH 8.5 was not as satisfactory as the use of dilute acid and fluoride as mentioned above. It was better than the other techniques, however.

Addition of fluoride to dilute acid (0.025N HCl) repressed the solubility of certain forms of phosphorus found in calcareous soils which were extracted by acid alone. Apparently the portion of the phosphorus not repressed by fluoride, insofar as its solubility is concerned, corresponded rather closely to that which was usable by wheat plants. Therefore, good agreement was obtained between this method of chemically extracting available phosphorus and plant growth response to added phosphorus. Addition of 1.0N CaCl2 to the extracting solution, as a substitute for fluoride, did not aid materially in improving the usefulness of dilute acid solution as a means of extracting “available” phosphorus. It did repress somewhat the solubility of phosphorus, however.

The acid‐fluoride combination (0.025N HCl + 0.03N NH4F), most acceptable for use with the calcareous soils, also was adapted for use with soils from central and eastern Kansas, most of which were acid in reaction. This method of extracting phosphorus was useful in evaluating availability of phosphorus in either untreated soils or in soils after the addition of rock phosphate. Likewise it was useful in measuring the release of phosphorus from rock phosphate to forms in the soil which may be regarded as available for plant utilization.

Extraction of phosphorus from pure chemical compounds by means of the dilute acid‐fluoride technique provided additional information.
Ring Growth of Plants
Authors: Harper W. G.
Published: July 2010

This paper discusses the spectacular rings formed among stands of ringgrass (Muhlenbergia torreyi) and mentions that this type of growth occurs in many places and among many plants in the arid and semiarid Southwestern States. Brief physical and chemical characteristics of soils where ring growth occurs are given and speculations are made about conditions that contribute to formation of the rings.
Some Meteorological Aspects of Evapotranspiration
Authors: Halstead Maurice H. , Covey Winton
Published: July 2010

During the past decade increasing attention has been given to various engineering type equations designed to estimate, from available climatic data, the amount of water used by plants.

Some of the basic assumptions involved in these equations are examined in the ligh to frecent advances in knowledge of the physical processes at the earth‐atmosphere interface.

It is found that the majority of equations involving the concept of potential evapotranspiration or consumptive use tend to assume a homogeneous soil moisture regime infinite in horizontal extent. Therefore, it has been difficult to apply these equations to irrigation practice, which obviously must create isolated areas of above normal moisture.

Consequently, the problem is approached from the strictly physical point of view, and it is shown that a solution can be obtained, provided that sufficient knowledge of soil interactions is available.
Rate of Loss of Carbon from Georgia Soils
Authors: Giddens Joel
Published: July 2010

The organic content of forest soils in Georgia was found to be rapidly lowered by cultivation. A mean decrease from 3.29% organic matter to 1.43% was found upon sampling 29 locations of forest soils and adjoining areas cultivated 25 years or more. A 20% average reduction in carbon occurred for 6 forested Piedmont soils brought under simulated cultivation for 24 months.

Most of the carbon from green oats, crimson clover, and barnyard manure was lost in 24 months when added to cultivated Cecil soil at rates of 20 tons per acre. Sawdust and mature oat and wheat straw were more resistant. But even these materials decomposed fairly rapidly with simulated cultivation.

The 20,000‐ and 40,000‐pound application rates of green oats only slightly increased soil carbon after 12 months, and after 24 months only the 40,000‐pound rate was higher (but not statistically) than the control. Rates of 2,000 and 5,000 pounds of green oats resulted in a slight decrease of soil carbon over the control after 24 months (but this was also not statistically significant at the 5% level).
The Effect of Drainage on the Weathering of the Clay Minerals in the Allenwood Catena of Pennsylvania
Authors: Johnson L. J. , Jeffries C. D.
Published: July 2010

The clay minerals from each horizon of a poorly‐drained and well‐drained member of the Allenwood catena were examined by X‐ray methods. In both drainage members the weathering sequence found was: mica (illite) → mica intermediate → vermiculite → chlorite‐like. Apparently, drainage conditions controlled the degree of expression of this weathering sequence in the two soils investigated.
Transmission of Gamma Radiation by Soils and Soil Densitometry
Authors: van Bavel C. H. M. , Underwood N. , Ragar S. R.
Published: July 2010

The theoretical basis for gamma densitometry of soil by transmission is reviewed. It is stressed that the familiar exponential‐inverse square law applies only to primary radiation. Data obtained with five different soils show such to be the case. Inclusion of secondary radiation in the measurement results in unwanted complications. The separation of the two types of radiation is achieved by scintillation counting and electronic discrimination.
Alfalfa Growth as Affected by Aeration and Soil Moisture Stress under Flood Irrigation
Authors: Kemper W. D. , Amemiya M.
Published: July 2010

Periodic lowering of oxygen content of the soil atmosphere to 13% or less for periods of 2 or 3 days appeared to have no adverse effects on alfalfa growth. If there were any adverse effects, they were entirely masked by the dominating effect of reduced soil moisture stress. When hydraulic moisture stress reached approximately 0.2 atm. at the 10‐inch depth, growth rate was greatly curtailed. When combined with the osmotic component of soil moisture stress, 0.2 atm. hydraulic stress resulted in total soil‐moisture stresses of about 1.9 and 2.8 atm. on leached and unleached plots, respectively.

In one series of irrigations where 17 inches of water were applied, the soil surface was sealed against diffusion of oxygen for at least 8 days. During this time the average oxygen content in the root zone dropped to 6% with individual readings as low as 3%. Alfalfa on these plots grew much better than did alfalfa on adjacent plots which received normal irrigation.
Physical and Chemical Properties of Soil Aggregates in a Brunizem Soil
Authors: Wittmuss H. D. , Mazurak A. P.
Published: July 2010

A surface sample of Sharpsburg silty clay loam was separated into aggregate fractions of diameters 4760 to 2380µ, 2380 to 1190µ, + … +, 37 to 18.5µ by means of rotary sieves and elutriators. A similar separation was made for primary particles. Each fraction of aggregates was analyzed for chemical and physical properties. The physical properties of aggregates were compared with those of primary particles.

Data on water stability of aggregates show that as the diameter of aggregates decreased the stability increased. Particularly, aggregates of diameter 74 to 37µ and 37 to 18.5µ were different from the other fractions. Some of the differences in properties were: higher degree of aggregation, percentage of primary particles, available phosphorus, and exchangeable Ca++; lower moisture retention, percentage of organic matter, total nitrogen content, and exchangeable H+.

At complete water saturation, aggregates and particles wetted under partial vacuum held greater amounts of water on a volume basis than did aggregates and particles wetted under atmospheric pressure. However, as tension was applied, more water was released from the aggregates and particles wetted under partial vacuum than under atmospheric pressure. At increased tensions, the differences between the two methods of wetting were less marked. At tensions of 0.33 atm. and higher, the moisture contents were nearly identical.

Aggregates treated with VAMA soil additive, under both vacuum‐wetting and atmospheric‐wetting, released more water at successive tensions than did those without the additive.
Compression of Soil by Isotropic Stress
Authors: McMurdie John L. , Day Paul R.
Published: July 2010

Loose packs of moist soil aggregates were encased in thin, cylindrical rubber membranes and subjected externally to air pressure in a triaxial test cell. The pressure was increased in increments, and the volume of the pack was determined from the axial strain after the rate of strain became less than 0.01% per minute at each step.

The stress‐strain measurements revealed certain characteristics of the compaction process. The soil aggregates were deformed plastically during loading and had developed a condition of “plastic set” at the end of each step. However, the system expanded substantially when the pressure was released. This effect has been attributed to translocation of water within the aggregates as a result of differential stress. The mechanical behavior of moist soil aggregates is different in this respect from the behavior expected of perfectly plastic grains under the same conditions.

A new sequence of plastic deformations occurred when the precompacted samples were recompressed to pressures which exceeded those previously applied. The volumetric contraction of the pack resulting from pressure gave an almost continuous envelope which represented successive states of plastic equilibrium throughout the pack.
Proportionate Uptake of Soil and Fertilizer Phosphorus by Plants as Affected by Nitrogen Fertilization: I. Growth Chamber Experiment
Authors: Grunes D. L. , Viets F. G. , Shih S. H.
Published: July 2010

An experiment was conducted to determine the effect of source and placement of nitrogen on the relative availability of fertilizer and soil phosphorus to plants. Barley was grown on seven soils in a controlled light‐temperature chamber. The addition of nitrogen fertilizer generally increased the percent of the total phosphorus absorbed by plants from bands of concentrated superphosphate. The addition of ammonium sulfate with the phosphorus band was generally more effective in increasing the percent of the total plant phosphorus derived from the fertilizer than was separating the nitrogen and phosphorus bands. Placement of sodium nitrate with, or on the opposite side of the plants from, the phosphorus band were approximately equally effective methods for increasing the percent of the total plant phosphorus absorbed from the fertilizer.

Indications are that the effect of nitrogen, on increasing the relative uptake of banded fertilizer phosphorus, was associated with increased top and root growth, and also with decrease in soil pH.

Detailed studies on one soil indicate that, when the phosphorus fertilizer was thoroughly mixed with the soil, the addition of nitrogen fertilizers did not increase the percent of the total phosphorus absorbed by plants from the fertilizer.
Desert Pavement and Vesicular Layer of Some Soils of the Desert of the Lahontan Basin, Nevada
Authors: Springer M. E.
Published: July 2010

Desert pavement and vesicular layer are described as distinct horizons of some Gray Desert soils. Distribution of > 2‐mm. and < 2‐mm. particles in the profile along with laboratory tests suggest that accumulation of gravel and stones at the surface to form a desert pavement is not due solely to removal of finer material by wind or water. There has also been some upward movement of coarse fragments from the nearly stone‐free layers below.

Some properties of vesicular layers are pointed out by field and laboratory studies. Natural vesicular structure was destroyed by sieving and a new, but similar, structure formed by merely wetting and drying the soil. This led to a hypothesis for origin of the vesicular layer as a pedogenic horizon.
The Use of Undisturbed Soil Cores to Investigate the Reclamation of Saline and Alkali Soils
Authors: Amemiya M. , Robinson C. W.
Published: July 2010

Field leaching investigations relative to the reclamation of saline and alkali soils generally require considerable land area, as well as time and personnel, for establishing and maintaining such studies. Concurrent with a field leaching experiment a laboratory leaching study was made to determine the relationship between results obtained from undisturbed cores in the laboratory and those obtained from field plots. Changes in infiltration rate, soluble salts, and exchangeable‐sodium‐percentage due to leaching, with and without gypsum, were compared.

In view of the similarity of results obtained from undisturbed cores in the laboratory and field plots, it appears that soil cores, properly encased, can be used to predict with reasonable accuracy the reclaimability of saline and alkali soils. Although laboratory studies will not replace field investigations, cores could be used in making preliminary studies during period outside of the field season. The information thus obtained could then be used in the final selection of treatments to be considered in the field.
Anomalies in Techniques for Preparing H‐Bentonites
Authors: Aldrich D. G. , Buchanan J. R.
Published: July 2010

Various procedures for the preparation of H‐bentonites to be used in physical‐chemical studies of clay systems have been examined. Their effects upon the exchangeable H and Al content of these bentonites have been evaluated by titration curves and chemical analyses.

A procedure for reducing the amount of exchangeable Al in such preparations is proposed. This procedure involves pretreatment of the bentonite suspension with hydrochloric acid and sodium chloride solutions followed by removal of excess electrolyte and passage of the suspension through an H‐resin column.

The exchangeable H and Al status of bentonites thus prepared is discussed.
Determination of Organic Phosphorus in Soils: III. Comparison of Methods
Authors: Van Diest A. , Black C. A.
Published: July 2010

Kaila and Virtanen found that in most of the soils they analyzed for organic phosphorus they obtained a higher figure with an extraction method they proposed than with the extraction method proposed earlier by Mehta and coworkers. Analyses of samples of five soils by the authors showed that the Mehta method yielded more organic phosphorus than the Kaila‐Virtanen method in all five samples.
Investigation of a Thermal Method for the Determination of Fixed Potassium in Soils
Authors: Legg J. O. , Axley J. H.
Published: July 2010

The release of K from soils according to the thermal method proposed by Kolterman and Truog was studied. This method involves heating an NH4‐saturated sample at 500°C. for 2 hours, followed by extraction of the K made exchangeable with ammonium acetate. The proponents of this method found that successive treatments released K from certain soils and clay minerals in a definite manner such that the slope of the lines formed by plotting the log K released against the treatment number was constant for all of the materials tested. The assumption that the slope would remain constant for all soils permitted the calculation of the total amount of fixed K from the results of only one or two heating and extraction treatments.

A group of soils with known K release characteristics was subjected to six successive heating and extraction treatments. The release of K from the different soils did not follow the expected pattern, however, since the slope of the log K plots did not remain constant for all soils. This discrepancy invalidates the method of calculating the total fixed K in the soil as proposed by Kolterman and Truog.

The data suggest the possibility of using the thermal method for determining the relative capacity of soil to supply nonexchangeable K to plants. A single heating and extraction treatment was as effective as a series of successive treatments in this regard.

Potassium release characteristics of a number of Maryland soil profiles were also studied by means of the thermal method. Potassium released by successive treatments varied greatly among soils and among horizons of each soil profile.
Nitrification in Grassland Soils
Authors: Soulides D. A. , Clark Francis E.
Published: July 2010

Nitrification studies were made on seven paired soil samples representing closely adjacent grassland and intertilled sites in the following soils: Codorus silt loam, Bladen clay loam, Cecil sandy loam, Hixton fine sandy loam, Fayette silt loam, Honeoye silt loam, and Pachappa sandy loam. All samples were incubated unamended and with 0.1% urea for periods of 2, 4, 6, and 9 weeks. Determinations were made for ammonia, nitrite, and nitrate nitrogen, and for urea nitrogen when indicated.

Grassland samples of the Codorus and Bladen soils, pH 4.7 and 4.9, respectively, showed accumulations of ammonia when incubated unamended. Such accumulations were not apparent in the five remaining grassland samples ranging in pH from 5.7 to 7.9. All grassland samples, irrespective of pH, when amended with 0.1% urea showed higher retention of ammonia and lesser nitrate production than did their intertilled counterparts. Urea‐amended soils initially alkaline or becoming alkaline following addition of urea showed nitrite accumulation, irrespective of whether the samples came from grassland or intertilled sites. Soils showing nitrite accumulation showed greater nitrogen deficits than did the remaining soils. Greater nitrogen deficits were commonly encountered in the grassland than in the intertilled members of paired, urea‐treated samples. There appeared a direct relationship between nitrite accumulation and magnitude of nitrogen deficit.
Response of Coniferous Seedlings to Soil Applications of Calcium and Magnesium Fertilizers
Authors: Voigt G. K. , Stoeckeler J. H. , Wilde S. A.
Published: July 2010

Coniferous seedlings and transplants growing in two nurseries located on coarse sandy soils in northern Wisconsin showed intense yellowing of the outer portions of needles or, in severe cases, the entire foliage. This condition was accompanied by a greatly reduced rate of growth. Greenhouse and sample plot trials revealed that the yellowing was caused by acute deficiency of both calcium and magnesium in available or exchangeable form. The results of soil and foliar analyses suggested antagonistic interrelationships between calcium and magnesium and potassium. The normal color and rate of growth of seedlings were restored by application of 1 ton per acre of dolomitic limestone. A similar effect was produced by rototilling a 6‐inch topdressing of leaf mold from a productive hardwood‐coniferous stand.
Water Vapor Transfer in Dry Soil
Authors: Hanks R. J.
Published: July 2010

Water vapor transfer in three dry soils was measured. The influence of porosity and depth of dry soil was investigated. Measurements were made primarily under isothermal conditions. Some measurements were made on one soil under nonisothermal conditions where the samples were radiated with a heat lamp. Liquid water movement was eliminated as a factor by treating the soil with a chemical water repellent.

Calculations of water vapor transfer based on simple diffusion were made. The ratio of measured to calculated values was 1.38 for the Ladysmith silty clay loam, 1.32 for the Geary silt loam, and 1.04 for the Sarpy fine sandy loam. Porosity and depth of dry soil had no measurable influence on the ratio of measured to calculated values. This suggests that diffusion is the primary process involved.

The ratio of the measured to calculated values for the Geary silt loam was 1.23 for the radiated samples. This is slightly less than the ratio measured for isothermal conditions which, considering the errors involved, indicates that simple diffusion theory is approximately correct for water vapor transfer in dry soil under both isothermal and nonisothermal conditions.
Separation and Determination of Total Copper and Zinc in Soils
Authors: Pratt P. F. , Bradford G. R.
Published: July 2010

Procedures for the anion‐exchange separation of Cu and Zn from each other and from other elements, including Fe, are described. An aliquot of soil extract containing Fe in the ferric form and sufficient HCl to make 3M HCl is added to the resin columns, and the columns are washed with 3M HCl to remove ions that do not form or that form weak negative chloride complexes in HCl. The Cu is then eluted with 3M HCl. Ferric‐Fe, which moves slowly in the 3M HCl, is eluted with 1M HCl, after which the Zn is eluted with 0.001M HCl. The Cu and Zn are determined colorimetrically by the use of zincon (2‐carboxy‐2'‐hydroxy‐5'‐sulfoformazylbenzene).

The separation and determination of Cu and Zn by these procedures give values in good agreement with dithizone extractions and determinations. The advantages of the new procedures are their simplicity and rapidity. Digestion with HClO4 does not completely dissolve Zn from soil samples.
Yield and Quality of Pangolagrass and Bahiagrass as Affected by Rate and Frequency of Fertilization
Authors: Engibous J. C. , Friedmann W. J. , Gillis M. B.
Published: July 2010

Field studies were carried out to determine the effect of rate and frequency of fertilization, primarily nitrogen, on the total production of forage and crude protein of Pensacola Bahiagrass and Pangolagrass under central Florida conditions, and to estimate their persistence under conditions of high fertility.

The optimum nitrogen fertilization rate for Bahiagrass over the 5‐year period was 240 pounds per acre applied in 2 applications per year. Bahiagrass was damaged by single applications of greater than 240 pounds of nitrogen. The data showed that 200 pounds each of P2O5 and K2O represented more than adequate levels of these nutrients. There was no benefit from split application of phosphorus and potassium, which were applied at 200 pounds (oxide basis) per year.

Pangolagrass responded to higher levels of nitrogen application—the optimum level was 320 pounds of nitrogen per acre per year. This grass can tolerate single applications of nitrogen up to 480 pounds per acre. In terms of forage or protein production, there was no advantage in split applications of nitrogen.
Molybdenum Response of Alfalfa on Indiana Soils in the Greenhouse
Authors: Foy C. D. , Barber S. A.
Published: July 2010

Greenhouse experiments were conducted to determine the response of alfalfa to Mo on Indiana soils.

Twenty‐five soils, representing 18 soil types from the major soil areas of Indiana, were used. The pH of the soils ranged from 4.8 to 7.4. Treatments included combinations of no lime; 250 pounds of CaCO3 per acre, mixed with the surface inch of soil; limed according to soil test; no Mo; and 2 pounds of Mo per acre. Three cuttings of alfalfa were obtained.

Mo produced significant yield increases on 9 of the 18 soil types studied, and 7 others gave responses approaching significance. A significant response to Mo was obtained at the high rate of lime on 2 soils, and on 6 other soils increases were obtained which approached significance. This suggests a deficiency of total Mo in these soils. Mo treatment reduced alfalfa yields on 3 of the acid soils which received the high rate of lime and on I soil having an initial pH of 7.0.

Results with one soil indicated that drying prior to cropping increased the response to Mo.
Chernozems and Associated Soils of Eastern North Dakota: Some Properties and Topographic Relationships
Authors: McClelland J. E. , Mogen C. A. , Johnson W.M. , Schroer F. W. , Allen J. S.
Published: July 2010

Chernozems may be associated with Humic‐Gley soils, Calcium Carbonate Solonchaks and Regosols and, less commonly, with solonetzic soils. The morphology of these soils, particularly of the Chernozems and Calcium Carbonate Solonchaks, is discussed. Some chemical and physical data are presented.
Fragipan Soils of Illinois: II. Mineralogy in Reference to Parent Material Uniformity of Hosmer Silt Loam
Authors: Grossman R. B. , Stephen I. , Fehrenbacher J. B. , Beavers A. H. , Parker J. M.
Published: July 2010

The mineralogy of Hosmer silt loam, a bisequal soil with a fragipan, was investigated in order to determine whether there is a lithological discontinuity between the parent material of the upper and lower sequum.

Differences observed between the two sequa in respect to the mineralogy of the heavy and light, silt‐size fractions may be accounted for by a progressive decrease in the weathering intensity with depth and are not suggestive of a lithological discontinuity in parent material. The clay mineralogy for the B horizons of the two sequa was similar for the < 0.2µ and the 0.2µ to 2.0µ fractions, taken individually. However, for the total clay fraction, a higher percent of montmorillonite was found in the B′2 horizon of the lower sequum; this may be explained on the basis of illuviation.
Constancy of the Sum of Mica Unit Cell Potassium Surface and Interlayer Sorption Surface in Vermiculite‐Illite Clays
Authors: Mehra O. P. , Jackson M. L.
Published: July 2010

The total unit cell planar specific surface was computed as the sum of planar sorption surface (by a glycerol gravimetric method) and the mica unit cell interplanar surface (corresponding to the K). This sum was found to be constant for a given unit cell formula weight, averaging 773 m.2/g. with a standard deviation of ±12.7 or about ±2%. For example, a Colorado vermiculite had 1.63% K2O equivalent to 16.3% mica residue with a unit cell interplanar surface of 124 m.2/g.; this added to the measured 631 m.2/g. of planar sorption surface (glycerol sorbed on expanded or cleavage planes) gives a total planar surface of 755 m.2/g. Similarly, for coarse clay from Fithian, Illinois, the 5.61% K2O is equivalent to 56.1% of illite, with unit cell interplanar surface of 426 m.2/g. This, added to 235 m.2/g. of measured planar sorption surface, gives a total of 661 m.2/g. which when corrected to exclude 15% unexpanded minerals (kaolinite and chlorite) gives a total planar specific surface of 775 m.2/g. Wyoming montmorillonite had 803 m.2/g. of planar specific surface, comparing well with the theoretical, 808 m.2/g. This principle of unit cell planar specific surface constancy of 2:1 layer silicates shows that the mechanism of K release from mica is by cleavage, and gives an accurate tool for analysis of the rather generally occurring interstratified mixtures of expanding 2:1 layer silicate minerals with micas in soils and sediments.
Solutions of the Flow Equation for the Drying of Soils and Other Porous Media
Authors: Gardner W. R.
Published: July 2010

Numerical solutions of the flow equation for the drying of porous media have been obtained assuming an exponential relationship between diffusivity and water content. Solutions are presented for both semi‐infinite and finite media for isothermal conditions, when gravity is absent or negligible. The rate of drying of laboratory soil columns is in good agreement with the numerical solutions. The rate of drying is controlled largely by the boundary conditions and physical characteristics of the soil that determine the rate of movement of water in the soil in the liquid phase.