bluuebunny/crossref_metadata_2025 huggingface dataset:
Some Empirical Relations of Soil‐Moisture Tensions
Authors: Miller W. McNab
Published: July 2010

An analysis was made to compare methods of designating soil mositure tension for an entire irrigation season. Using the field data from a sugar‐beet irrigation experiment, seasonal values for soil‐moisture tension at a given depth were calculated as a simple mean of all readings, and as a mean of the tensions just prior to each irrigation. These values were found to correlate closely with mean tensions calculated similarly to Taylor's mean integrated tension for a single depth. Yields were found to correlate equally well with either mean integrated tension or the mean of tensions prior to irrigation. Under soil and growth conditions encountered, no advantage was found in using mean integrated soil‐moisture tension or the arithmetic mean of all readings, in preference to the simpler mean of pre‐irrigation tensions.
Nutritional Groups of Soil Bacteria on the Roots of Barley and Oats
Authors: Wallage R. H. , King H. deL.
Published: July 2010

Barley and oats were grown each in five replicate field plots. At two stages of growth, namely the “tiller” and “head” stages, plants were removed and bacteria were isolated from composite samples of soil that adhered to the roots. Bacteria were also isolated from the soil between the rows of plants. The bacteria then were arranged into seven groups according to their growth in a variety of nutritional media; in general it was found that those requiring yeast extract occurred with the greatest frequency. The results were analysed statistically and it was found that specific ‘rhizosphere effects’ existed chiefly in relation to the age of the plants, and that those effects occurred more frequently with regard to barley than with oats. It was concluded that root excretions in the rhizosphere soils of barley and oats had little or no effect on the equilibrium of the nutritional groups. Emphasis is placed on the importance of replicating samples and analysing results statistically.
The Effect of Stubble Mulching on the Acid Soluble and Adsorbed Phosphorus in the Soil
Authors: Withee L. V. , McCalla T. M.
Published: July 2010

Plots having a 13‐ and 15‐year history of continuous plowing and stubble mulching were sampled and analyzed to determine if the two tillage practices had resulted in differences in the phosphorus content of the tilled layer. The plots were selected from two series of rotations of high and low fertility level established for the study of stubble mulching in relation to erosion, moisture storage and crop yields. The plots were sampled in three layers, 0 to 1, 1 to 3, and 3 to 6 inches. Determinations of acid soluble and adsorbed phosphorus were made on each of the composited soil samples.

There was a significant increase in the acid soluble and adsorbed phosphorus content of the surface inch of soil over that in the 3 to 6 inch layer of the subtilled plots. The variation in the acid soluble or adsorbed phosphorus in different depths of the plowed plots was consistently less than that of the stubble mulch plots. In all instances the subtilled plots contained more acid soluble and adsorbed phosphorus in the surface inch than did the plowed plots. There was very little difference in the phosphorus content of the 0 to 6 inch depth of the plots in stubble mulching or plowing.
A Comparison of Ammonium Acetate, Barium Acetate, and Buffered Barium Chloride Methods of Determining Cation Exchange Capacity
Authors: Pratt P. F. , Holowaychuk N.
Published: July 2010

The cation exchange capacities of several profile samples of soils were determined using three different methods. Total exchangeable cations were determined and used as a criterion for evaluating the different methods of determining the exchange capacity. For all soil samples the NH4OAc method underestimated the exchange capacity and so produced distorted exchange capacity profiles. The Ba(OAc)2 method gave exchange capacity values which were equal to the sum of exchangeable cations, except with highly acid soils where it gave low values. The BaCl2‐buffer exchange capacity gave values that were nearly equal to the sum of the exchangeable cations for all samples tested. The Ba(OAc)2 or BaCl2‐buffer methods, in which Ba is replaced by 0.05 N HCl and the Ba determined using an acetylene flame with a model 52 C Perkin‐Elmer photometer, cannot be used for some samples because of Ca interference. Some slightly acid soils gave sufficient Ca release during the HCl extraction to interfere in the Ba determination. This interference was removed by washing the soil with HCl before leaching with the BaCl2‐buffer and by replacing the barium with NH4OAc.
The Effect of Some Soil Conditioners on Friability and Compactibility of Soils
Authors: Jamison Vernon C.
Published: July 2010

The effect is reported of aggregate stabilization with vinyl acetate maleic acid copolymer upon the breaking strength (Modulus of rupture) of soil briquets molded from several soils of known mineral composition at the moisture content equivalent to the one‐third atm. point of the treated samples. In most cases the stabilization decreased breaking strength, the differences being greatest at the lower bulk densities. Soils rich in montmorillonite gave generally higher Modulus of rupture values than those rich in kaolinite. Aggregate stabilization with this polymer also reduced compressibility of soils with 1:1 lattice type clay dominant, especially at the higher pressures used. The breaking strength of briquets and the water stability of the 1.0 to 0.25 aggregates tests were compared for several materials used to stabilize Lloyd clay aggregates. The various materials affected these two properties differently. A material that increased aggregate stability greatly does not necessarily reduce the briquet breaking strength appreciably. Inter‐aggregate and intra‐aggregate bonding is discussed in light of the results. Field and laboratory tests are reported showing that the method of soil treatment with a stabilizer and weather conditions after treatment will modify the effect upon soil crusts formed. Stabilizers sprayed on the surface may give rise to tough soil‐plastic crusts that are harder than natural crusts upon drying.
The Use and Effectiveness of Various Copper Bearing Materials for Application to Everglades Organic Soils
Authors: Kretschmer Albert E. , Forsee W. T.
Published: July 2010

One of the classic examples of plant response to Cu is found in the vast area of organic soils of Peninsular Florida. Most crops failed to grow on these soils until the middle 1920's when the need for Cu was first demonstrated. Tremendous growth response of various leafy vegetables, cruciferous plants, root crops, eggplant, tomatoes, and certain forage crops have been obtained with initial applications of 50 pounds an acre of copper sulfate. In recent years it has been found that copper oxide is at least as effective as copper sulfate in supplying sufficient copper for maximum plant growth. Results of greenhouse tests indicated that either source is as effective when added to the soil in mixed fertilizer as when added separately. Further work showed that plant response to Cu on virgin peaty muck soil was the same whether 12 or 24 pounds of Cu per acre was applied.

A field experiment comparing two rates of copper oxide and copper sulfate showed the effects of plant varietal differences with respect to Cu deficiency symptoms. Southland oats and ryegrass were seeded in the test area where St. Augustinegrass cuttings had been planted. Copper deficiency symptoms of oat plants growing on the no‐Cu plots were much more pronounced as indicated by reduced yields and chlorosis than were the symptoms for ryegrass. Copper contents of the oat plants were lower for the no‐Cu plots but no differences were noted for plants treated with the oxide or sulfate at 12 or 24 pounds of Cu. St. Augustinegrass and pangolagrass (fertilized in a similar manner) showed similar findings.

Copper analyses of various forages grown in the greenhouse with additions of 1,000 pounds of copper sulfate per acre, indicated that St. Augustinegrass, caribgrass, and paragrass, absorbed more Cu than bahiagrass, fescuegrass and “giant” pangolagrass. Copper contents of red clover and subterranean clover growing in the field, were significantly greater than ryegrass, oats, vetch, alfalfa, and hubam clover. Copper contents of forages taken from various soils in the area indicated that Cu deficiency, per se, of cattle should not be widespread in this area under proper fertilization, including Cu additions.
Freezing and Thawing, and Wetting and Drying in Soils Treated with Organic Chemicals
Authors: Willis Wayne O.
Published: July 2010

Laboratory experiments were performed to determine the effects of cycles of freezing and thawing or of wetting and drying on the percentage of water stable aggregates of soils treated with organic chemicals. The chemicals used were HPAN (a hydrolyzed polyacrylonitrile), SC‐50 (a water soluble sodium methyl siliconate) and PR‐51 (a water soluble alkylated aromatic sulfonate). Rates of application were 0.1% HPAN, 0.2% SC‐50 or 0.0013% PR‐51. Seven different soils were tested. Two of the soils were separately treated with HPAN, SC‐50 and PR‐51, and five additional soils were treated only with HPAN. The soils were tested for water stability, by wet sieving, after 0, 1, 5, 10 and 20 cycles of freezing and thawing, and after 0, 1, 5 and 10 cycles of wetting and drying. Results showed that soils which had undergone the effects of freezing and thawing generally had a lower percentage of aggregates > 0.25 mm., than those which had not been subjected to the process; this was also true for cycles of wetting and drying but to a lesser extent. The different soils responded with significant difference to the effects of freezing and thawing and of wetting and drying in interaction with the organic chemicals, except that the use of PR‐51 resulted in no significant differences.
Simplified Air Permeameters for Soil in Place
Authors: Grover Ben L.
Published: July 2010

A simplified basic design is described and utilized in the construction of three field air permeameters. The basic design incorporates features of a gasometer and consists of a float, an annular water‐filled reservoir and an inlet tube. The float, which is open‐bottomed, rests on the water in the reservoir, to form an air chamber. The inlet tube is affixed to the soil and is also fastened to the inner wall of the reservoir. The air from the air chamber enters into the soil by passing down through a tube, which forms the inner wall of the reservoir, and through the inlet tube into the soil. The float falls as the air enters the soil. The rate of fall is a measure of the permeability. The effective volume of air provided by this type of permeameter is much larger than that provided by previous equipment of similar size. Each of the three field air permeameters was designed for one of these special purposes: (a) to measure permeability to a given depth, (b) to measure permeability to a given depth and be able to use a part of the same equipment for other types of physical measurements, without disturbing the soil, (c) to measure permeability of thin soil layers, as crusts, or silted‐over surface soil. Data are given to show the type of results which can be obtained with these permeameters.
Soil Moisture Determination by a Portable Neutron Scattering Moisture Meter
Authors: Stone J. F. , Kirkham D. , Read A. A.
Published: July 2010

A portable, battery‐powered device for measurement of soil moisture by neutron scattering has been constructed and used for field measurements. The equipment, aside from being portable, differs from previously reported devices of this type as follows: (a) A fast neutron source in the form of an annulus is placed about the center of a slow neutron detecting tube; (b) Recently developed glow transfer tubes are used for absolute neutron count determinations; (c) A calibrating volume of paraffin, which is also used as a neutron shield, is incorporated as a part of the source‐detector carrying case, to permit simple field checking and standardization of the device. The detector tube is partially shielded with cadmium to reduce the vertical extent of the soil “sample” contributing to the neutron count. Field data are presented. It was found, by locating the source‐detector at various depths in pipes sunk vertically into the soil, that, except for the surface 6 to 9 inches, the equipment generally gave the soil moisture per unit soil bulk volume, within the range of the standard deviation of gravimetric determinations. A single calibration curve serves for all soils tested (sand, silt loam, silty clay loam). The equipment, complete with batteries, lead and paraffin shielding, weighs 45 pounds. The shielding protects the operator against radiation hazard and is sufficient for at least 8 hours per day use, 6 days a week.
Predicting Nitrogen Fertilizer Needs of Iowa Soils: IV. Evaluation of Nitrate Production as a Criterion of Nitrogen Availability
Authors: Munson Robert D. , Stanford George
Published: July 2010

Preceding papers in this series have traced the development of a suitable method for assessing the relative nitrogen‐supplying power of soils and its correlation with crop response to nitrogen fertilization in the field. This method has been shown to be of value in predicting the need for nitrogen fertilizer in Iowa soils.

The present study, conducted under controlled greenhouse conditions, was designed to evaluate critically the utility of soil nitrate release as a basis for establishing the relative nitrogen status of soils. The 21 soils used in this investigation represent a wide range in nitrogen‐supplying capacity. Four levels of nitrogen fertilizer were applied to pots and German millet was grown.

The relation between total nitrogen uptake by the crop and level of applied nitrogen was linear for all soils studied. Extrapolation of the linear regressions provided values which reflected the relative contents of available nitrogen in the soils. These values which have been termed “N‐values” are expressed in units of applied nitrogen. Also, N‐values correlated highly with the total nitrogen uptake of the check pots. Both N‐values and nitrogen uptake by the plants were highly correlated with nitrate nitrogen released during a 2‐week period of incubation. Considerably lower correlations were found in relating these criteria to total soil nitrogen or to values obtained by the alkaline permanganate method.
Subsidence of Organic Soils in the Florida Everglades
Authors: Stephens John C.
Published: July 2010

Subsidence of peat and muck soils in the Everglades has been observed and recorded since 1914. An average subsidence rate of approximately 1¼ inches per year was found by periodic survey over 15 profile lines. Water‐table test plots showed that loss of peat soil depended directly upon depth of drainage. The relation is expressed by the equation , in which x equals subsidence rate in inches per year and y equals average depth of water table in inches. This rate is about double that found in similar studies by investigators in Indiana. Isopachous charts showing the original depth of the peat soils in 1912, in 1925, and in 1950 are shown for the agricultural area near Lake Okeechobee and projected to the year A.D. 2000. Steps which will minimize soil losses are outlined.
Height Growth Response of Douglas Fir to Nitrogen Fertilization
Authors: Gessel Stanley P. , Walker Richard B.
Published: July 2010

This paper presents the results of initial nitrogen fertilization trials on 15 to 20‐year old natural Douglas fir stands growing on poor sites (Site Class IV, V) in western Washington. Annual height growth was used as the criterion of response. On both shallow residual and deep glacial outwash soils response to nitrogen was very marked. Larger more vigorous trees responded more than smaller trees and resulted in more rapid suppression of these small trees. Foliage color changed from yellow to dark green after fertilization and before height growth response. Nitrogen content of needles increased from less than 1% to 1.2 to 1.8% after fertilization. Some aspects of fertilization of forest lands are discussed including use of fertilizers for Christmas tree production.
Effect of Biocides on the Development of Ectotrophic Mycorrhizae in Monterey Pine Seedlings
Authors: Wilde S. A. , Persidsky D. J.
Published: July 2010

Sandy nursery soil of siliceous outwash, autochthonously inoculated with mycorrhizal fungi, was treated with chlordane, benzene hexachloride, thiosan, calomel, formaldehyde, aluminum sulfate, allyl alcohol, and Stoddard solvent at the rates common in nursery practice. After incubation, the cultures were planted to surface‐sterilized seed of Pinus radiata, and the external and internal development of mycorrhizal short roots was recorded at definite intervals. The internal alterations of mycorrhizae under the influence of eradicants were characterized by irregularities in the shape of the fungal mantle, restricted penetration of mycelia, and reduced development of the Hartig net. The external modifications of the short roots suggested that biocides cause radical changes in the exudates of rhizospheric organisms. The effect of eradicants varied with the nature of chemical compounds and their rate of application, but some of the observed modifications of mycotrophic organs were symptomatic of the eradicants applied.
Tentative Technique for Determining the Influence of Soil on the Growth of Forest Plantations
Authors: Leaf Albert L. , Keller Theodor
Published: July 2010

This paper reports analytical techniques for the determination of the influence of soil on the growth of red pine and white spruce plantations. The ecological homogeneity of the plantation or portion thereof is checked by a transect survey of tree heights and diameters and soil analysis. The estimate of the rate of growth is made on the basis of stem analyses of the average sample trees. The field and laboratory investigation of soil properties is supplemented by foliar analysis and, in the case of hydromorphic soils, by the determination of properties of ground water. The importance of an accurate estimate of the density of nurse stands is stressed. The applicability of suggested methods is illustrated by concrete examples.
Representation of Soil Aggregate‐Size Distribution by a Logarithmic‐Normal Distribution
Authors: Gardner W. R.
Published: July 2010

The need for a simple method of representing a soil aggregatesize distribution is well recognized. Over 200 aggregate‐size distributions which have appeared in the soils literature were examined to determine if they could be fitted by an analytical expression. A majority of these distributions was found to be logarithmic‐normal or very nearly so. Such distributions can be completely characterized by specifying the geometric mean diameter and standard deviation. The logarithmic‐normal distribution function and its application to aggregate‐size distributions are discussed. An illustrative example is given.
Effect of Some Long‐Time Rotations on the Amino Acid Composition of the Soil
Authors: Stevenson F. J.
Published: July 2010

The technique of ion exchange chromatography has been further refined for the isolation and quantitative determination of the ninhydrin‐positive components of soil hydrolysates. The method was used to determine the effect of some long‐time rotations on the distribution of amino acids in soils. The soils used for this purpose were taken from the Morrow Plots at the University of Illinois.

It was found that these plots differed in both the proportion of the soil nitrogen present as α‐amino acid nitrogen and in the relative distribution of amino acids. The most striking difference was in the basic amino acid content of these soils, where a high quantity of basic compounds was associated with the untreated rotations. An explanation is given to account for these observations.
Effect of Bromide from a Soil Fumigant and from CaBr2 on Growth and Chemical Composition of Citrus Plants
Authors: Martin J. P. , Helmkamp G. K. , Ervin J. O.
Published: July 2010

A study was made to determine the influence of soil Br from CaBr2 treatments or from preplanting fumigation of soil with ethylene dibromide on growth and chemical composition of citrus plants. The treatments did not affect the percentages of Ca, Mg, K, Na, or P in the plants. Preplanting fumigation with ethylene dibromide or treatment with CaBr2 reduced growth of citrus seedlings, whereas fumigation with ethylene dichloride or treatment with CaCl2 exerted little or no influence. In one soil, citrus leaf Br concentrations of 0.17, 0.33, 0.40, 1.3, and 1.8% were associated with 12, 22, 31, 57, and 90% reduction in growth, respectively. In two soils certain citrus leaf Br concentrations originating either from soil CaBr2 applications or pretreatment of the soil with ethylene dibromide fumigant were associated with comparable growth retardation.

Carrot and lima bean plants grown for comparison were much more tolerant to Br than were citrus plants. A leaf concentration of 2.5% Br did not reduce growth of carrots. Lima beans tolerated 1.5% or more leaf Br, while 0.2% was sufficient to reduce growth of citrus plants.
Soils of the Beryl‐Enterprise Area, Utah: Their Origin, Properties, and Classification
Authors: Ulrich Rudolph
Published: July 2010

Because of low average rainfall, sparse vegetative cover, and relatively gentle slopes, soil differences in the Beryl‐Enterprise area strongly reflect parent material and time factors of soil development. In the better drained, more recent, and somewhat older alluvial fan and terrace positions free of excess soluble salts, carbonates, and exchangeable sodium, soil development appears to progress from the Alluvial great soil group through various stages of the Sierozems, called minimal, medial, and maximal. Removal of lime from the A1 and B2 horizons, increasing clay formation and concentration in the B2 horizon, increasing lime in the Cea, and decreasing reaction in the A1 and B2 accompany these stages. In areas relatively high in carbonates, profile development has been dominated by lime movement and concentration in the Cea horizon. The soils are calcareous to the surface and show little evidence of clay formation, movement, or concentration. These soils are classified as Calcisols. Where excessive soluble salts, exchangeable sodium, or both have been an important factor, Solonetz development has resulted. Such soils are confined to the basin area and to minimal and medial stages of development.
Production of Sugar Beets Following Winter Green Manure Cropping in California: II. Soil Physical Conditions and Associated Crop Response
Authors: Williams W. A. , Doneen L. D. , Ririe David
Published: July 2010

A procedure is described for measuring volumetrically the rate of water infiltration in field furrows. The technique developed was used to determine the effect of green manure crops on soil structure during the growth of a succeeding crop of sugar beets. At one location a green manure crop of barley increased the rate of infiltration. This result was associated with an increase in sugar production where nitrogen fertilization insured optimum fertility. Tractor travel in furrows was observed to have a significant depressing effect on the rate of infiltration.
Uses of Soil‐Vegetation Survey Information in Road Construction
Authors: Fisher J. R. , Bradshaw K. E.
Published: July 2010

Engineers constructing roads in upland areas derive much information from soil‐vegetation survey data. Soil series characterized as to their behavior for road construction enable the engineer to lay out roads that pass through the areas of better soils and avoid the difficult ones. Vegetation data guide the engineer in routing his road to mature timber stands. They show him what problems will be involved in clearing rights‐of‐way. Much more work must be done in testing laboratories to determine bearing ratios, optimum moisture percentages, swell percentages, and other characteristics for soil series. However, field approximations of these data can be made, and these are all valuble aids to the engineer.
Solubility Product of Iron Phosphate
Authors: Chang S. C. , Jackson M. L.
Published: July 2010

The solubility product of iron phosphate was determined by both dissolution and precipitation methods in dilute salt solutions. Solution pH values slightly below the determined isoelectric pH of 2.75 for iron phosphate were employed to get determinable amounts of iron in the solution. The pKsp value was calculated from the ionic activities of Fe3+ and H2PO4‐ in the equilibrium solution by the following equation, pKsp = pFe3+ + pH2PO4‐ + 2pOH‐ which was found to coordinate the data most satisfactorily. The pKsp value of iron phosphate increased with a 1000‐fold decrease of the solid‐to‐solution ratio from 33.6 to 35.1. It increased from 33.0 to 33.2 over a 50‐fold decrease of the concentration of the precipitation reagents. A medial value of 33.5 was approached by the two procedures; however, for low iron phosphate‐solution ratios, such as those commonly employed for soil extraction, the applicable pKsp value agrees with the most dilute solid‐solution value of 35 or more. Similarly for aluminum phosphate, the applicable pKsp value extends as high as 32 for dilute suspensions. The variation in apparent solubility product with amount of solid per unit volume of solution is negligible compared to the magnitude of the pKsp which is the reciprocal of a billion trillion trillion. The calculations from solubility products show that aluminum phosphate and iron phosphate should precipitate and accumulate even in neutral soils, as observed experimentally.
Decomposability of Some Organic Sulfur Compounds in Soil
Authors: Frederick Lloyd R. , Starkey Robert L. , Segal William
Published: July 2010

Various organic sulfur compounds decomposed at different rates in soil under aerobic conditions. The sulfur was released rapidly from some compounds (mostly of natural origin) but only in negligible amounts from others. As estimated by formation of sulfate, the following compounds decomposed rapidly: cystine, taurine, sodium taurocholate, sulfosalicylic acid, and formaldehyde‐sodiumsulfoxylate. Decomposition of the last compound may have been non‐biological, at least in part. Thiamine decomposed slowly and there was slight decomposition of thiourea. There was no evidence of decomposition of the following: sulfanilic acid, sulfanilamide, sulfathiazole, sulfapyridine, mercaptoethanol, sodium diethyl‐dithiocarbamate, an alkyl‐aryl‐sulfonate, p‐thiocresol, 2‐mercaptobenzothiazole, sulfonmethane, phenyl thiourea, potassium ethyl xanthate, and ammonium sulfamate. Decomposition of the organic sulfur compounds as determined by sulfate production was not related to any type of sulfur linkage.

Decomposition of methionine was markedly different from that of the other sulfur compounds in that sulfate was not an end product. The sulfur was recovered as the volatile sulfur products methylthiol and dimethyl disulfide. The results indicate that the methylthiol was produced first and that the dimethyl disulfide arose from oxidation of methylthiol.

The abundance of soil microorganisms increased in the soils to which those organic compounds were added from which sulfate was formed. Thiourea, phenyl thiourea, and mercaptoethanol were toxic to the soil population at the concentrations of 1% or more that were used.

Decomposition of cystine, taurine, formaldehydesodium‐sulfoxylate, thiamine, and sulfosalicylic acid resulted in an increase in acidity due to the formation of sulfate and, probably also in some cases, of nitrate. There was little reaction change from sodium taurocholate. With methionine the reaction became first alkaline and then somewhat acid.
Movement of Ammonium Nitrogen in Soils
Authors: Ray H. E. , MacGregor J. M. , Schmidt E. L.
Published: July 2010

The distribution of applied ammonium nitrogen in four southern Minnesota soils maintained at constant moisture tension and nitrogen concentration was determined in the laboratory. Ammonium nitrate enriched with N15 in the ammonium ion was used as a source of nitrogen. The soils varied in texture from loamy fine sand to loam, and in exchange capacity from 3.2 to 34.2 me. per 100 g.

Movement of ammonium nitrogen in Anoka loamy fine sand was predominantly downward and lateral. In contrast, movement of ammonium nitrogen in Nicollet loam was nearly symmetrical with slightly greater upward and lateral movement than downward movement. Retention of applied ammonium nitrogen in the zone of injection amounted to 2.0 me. per 100 g. of soil in Anoka loamy fine sand, and to 14.4 me. per 100 g. in Nicollet loam. Movement and retention of ammonium nitrogen were intermediate in the Fayette silt loam and the Barnes loam.
The Effect of Longtime Use of Winter Cover Crops on Certain Physical Properties of Commerce Loam
Authors: Patrick W. H. , Haddon C. B. , Hendrix J. A.
Published: July 2010

A study has been made of certain physical properties of Commerce loam as affected by longtime use of winter cover crops preceding cotton. The treatments used were: (1) no treatment, (2) 40 pounds per acre of inorganic nitrogen, (3) common vetch, and (4) hairy vetch. The individual plots were sampled in 1955 and analyses made of the following soil properties: organic matter, total nitrogen, aggregation index, bulk density, noncapillary porosity, water permeability, field capacity, and wilting point.

The organic matter and total nitrogen contents were highest in the hairy vetch plots and lowest in the plots receiving 40 pounds per acre of nitrogen and in the untreated plots. The values for aggregation, bulk density, and noncapillary porosity showed that the physical condition of the soil was best in the hairy vetch plots, next best in the common vetch plots, and poorest in the untreated plots and the plots receiving 40 pounds per acre of nitrogen. The 25‐year average per acre yield of cotton from the different treatments was: hairy vetch, 2,000 pounds; common vetch, 1,680 pounds; 40 pounds of nitrogen, 1,470 pounds; and no treatment, 900 pounds. The ability of the 40 pounds of nitrogen to produce an increase in yield over the untreated plots was not reflected in an increased organic matter content or an improved soil physical condition.
The Effect of pH on the Uptake of Radioactive Isotopes from Solution by a Soil
Authors: Rhodes D. W.
Published: July 2010

The reactions with natural earth materials of fission products and plutonium are of current interest in the field of atomic energy waste disposal and soil chemistry.

Solutions containing less than 1 × 10‐9 moles per liter of selected radioisotopes were equilibrated with samples of a calcareous subsoil. The uptake of these radioactive isotopes by the soil was measured as a function of pH. The uptake of Cs137 was not affected appreciably by varying the pH between 4 and 10. The maximum uptake of Sr90 occurred at about pH 10 and decreased rapidly as the pH was lowered. The radioisotopes Pu239, Ce144, Zr95, ‐Nb95, Y91, and Ru106 exhibited a maximum uptake between approximately pH 4 and pH 8. Above pH 8 a region of reduced uptake occurred and persisted up to at least pH 11 for most of the polyvalent radioisotopes.

The addition of high concentrations of sodium salts to the solution inhibited the uptake of both Cs137 and Sr90 by soil. A relatively small concentration of phosphate (0.01 M) added to the system was found, in effect, to nullify the interference of sodium ion with the uptake of Sr90, but the phosphate ions had no apparent influence on the uptake of Cs137.
Nitrogen Loss in Gaseous Form from Soils as Influenced by Fertilizers and Management
Authors: Loewenstein H. , Engelbert L. E. , Attoe O. J. , Allen O. N.
Published: July 2010

The experiments reported here were aimed to ascertain the magnitude of gaseous loss of nitrogen in Spencer silt loam under greenhouse conditions, as affected by pH, form of nitrogenous fertilizer, energy material, and cropping. Four additions of 150 ppm. nitrogen each were made to both cropped and uncropped soils; four successive oat crops were grown on the former.

At field moisture levels large volatile losses of nitrogen occurred from the uncropped soil regardless of treatment. Over an 11‐month period these losses ranged from 35% in the soil at pH 5.5 amended with straw and nitrogen as (NH4)2SO4 to 72% in the soil at pH 6.5 with (NH4)2SO4 but no straw. In soils similarly treated and subsequently cropped with oats, the losses were between 7 to 8%.

In other experiments the levels of NO3, NH4, and total N in the uncropped Spencer silt loam at pH 6.5 were measured 8 times during a 1‐year period. Irrespective of the form of nitrogen added, presence or absence of straw, and whether liming occurred at the time of fertilization or 12 weeks earlier, the greatest decrease in total nitrogen occurred during the first 6 weeks after fertilization and thereafter remained more or less constant over the year. Approximately one‐half of the 300 ppm. nitrogen added was volatilized from the soil under each treatment. Concurrent increases in nitrate nitrogen levels occurred without exception.
Chemical and Physicochemical Properties of Soil Humic Colloids: III. Extraction of Organic Matter from Soils
Authors: Choudhri M. B. , Stevenson F. J.
Published: July 2010

A study was made of the effects of certain soil treatments on the amounts of humic acids and organic matter extracted by a number of reagents, including sodium pyrophosphate of different pH values, and alkali. The pretreatments were: (1) removal of carbonates and exchangeable bases, (2) removal of free iron and aluminum oxides by mild reducing reagents, and (3) removal of silicate minerals with hydrofluoric acid. The extraction of organic nitrogen was taken as an index of organic matter extracted.

Removal of calcium and free iron and aluminum oxides increased the solubility of organic matter in alkali but had no effect on extraction by pyrophosphate. The removal of silicate minerals by repeated treatment of the soil with hydrofluoric acid was particularly effective in facilitating the extraction of humic acids by pyrophosphate. The proportion of humic acid nitrogen extracted to total organic nitrogen extracted was considerably higher in pyrophosphate extracts than in extracts of other reagents.

Several organic‐complexing reagents, including cupferron, 8‐hydroxyquinoline, acetylacetone, and disodium dihydrogen ethylenediamino tetraacetate, were also tested and it was found that they were not as effective as neutral sodium pyrophosphate for removing soil organic matter. In addition, a procedure was proposed for mitigating autoxidation reactions during extraction of organic matter.
Sols Bruns Acides of the Northeastern United States
Authors: Baur A. J. , Lyford W. H.
Published: July 2010

Sols Bruns Acides is the name now used in Belgium, France, and possibly other European countries for a class of soils at the great soil group level. Similar soils have developed under forest vegetation in the Northeastern United States, and it is proposed that the same name be applied here. In the past these soils have been included with Brown Podzolic, weak Podzol, weak Gray‐Brown Podzolic or Red‐Yellow Podzolic soil groups. Morphologically, Sols Bruns Acides have a thin A1 horizon; a paler A2 or A2‐like horizon (possibly a B1 horizon) which is poorly differentiated from the B2 horizon; a B2 horizon with uniform color from top to bottom, weak subangular blocky structure, and silicate clay accumulation not evident or appearing only in traces. Sola of these soils are strongly to very strongly acid and have low base status. Distinction between Sols Bruns Acides and the Gray‐Brown Podzolic and Red‐Yellow Podzolic soils rests mainly on amounts of clay accumulation in the B horizon. Sols Bruns Acides differ from weak Podzols and Brown Podzolic soils mainly in color and structure of the B horizon. The latter have in the upper B horizon strong colors which fade with depth and weak, fine granular structure.
Characteristics of Eolian Influenced Soils in Connecticut: II. Chemical and Mineralogical Properties as Keys to Profile Mixing
Authors: Tamura Tsuneo , Ritchie A. , Swanson C. L. W. , Hanna R. M.
Published: July 2010

Underlying a small eolian soil deposit east of the Connecticut River, Triassic till and stratified sand and gravels had large particles, low free iron oxide content, red hue, and montmorin. The wind‐blown soil near the source had small particles, high free iron oxide content, brown color, and no montmorin. In the thinner soil mantle at a distance from the source larger particles appeared; the free iron oxide content decreased; the soil became redder; and montmorin appeared. All of these facts indicate that the distant profiles were mixed. An index of mixing based on mean size was defined using 0 for eolian sediment and 100 for the underlying deposit. The index was as great as 75 in the B and 50 in the A horizons. The presence of unstable montmorin and the scarcity of free iron oxide in the mixed profiles indicate that the mixing phenomenon was post glacial, relatively recent, and likely due to tree throw. From data on the Connecticut, Illinois and New Jersey deposits a prediction was made concerning the change in particle size with distance in any deposit.
Characteristics of Water Removal in a Tile‐Drained Humic‐Gley Soil
Authors: Taylor George S. , Goins Truman
Published: July 2010

A water table was established within a few inches of the ground surface on a tile‐drained Humic‐Gley soil, after which measurements of water‐table levels and soil moisture contents were made at various time intervals. The hydraulic conductivity of the A horizon (0 to 8 inches) was considerably greater than that of the B horizon (8 to 50 inches), as shown by auger‐hole permeability measurements. The drains were located in the B horizon at an average depth of 30 inches and with a lateral spacing of 40 feet.

During drawdown, the water‐table surfaces were nearly horizontal except in the region near the drains. When the water table receded from the ground surface to drain depth, approximately 0.50 inches of water were removed from the A horizon; whereas, only 0.10 inches were removed from the upper 22 inches of the B. An analysis of the drawdown and water‐removal characteristics indicated that the drains brought about rapid drainage in the A horizon but that deep seepage may account for significant water removal from the B. Although the A horizon was more than 50 times as permeable as the B, the A horizon was too shallow to permit significant water removal by lateral flow to the backfill.
Extraction of Potassium from Soils by Sulfuric Acid
Authors: Hunter A. H. , Pratt P. F.
Published: July 2010

Methods of extracting potassium from soils by use of sulfuric acid have been developed. The amounts of K extracted from several Ohio and New York soils by these methods were compared with those extracted by neutral 1N NH4OAc and boiling 1N HNO3 methods as means of furnishing a reliable index to the “plant‐available” K of soils.

Using H2SO4 method 1, amounts of K were extracted which were highly correlated with amounts of K extracted from soils by cropping. The correlation coefficient thus obtained was significantly different at the 1% level from the coefficients obtained by using ammonium acetate or boiling nitric acid.

The sulfuric acid methods developed are simple to use and, since an exact quantity of heat energy is furnished to the soil extraction system, these methods theoretically furnish a means of releasing a constant amount of non‐exchangeable K, due to breakdown of primary and secondary minerals, as well as the exchangeable K from a particular soil.
Identification of Clay Minerals in the Surface Horizons of Four Kentucky Soils
Authors: Dixon J. B. , Seay W. A.
Published: July 2010

Kentucky is a transitional area between two great soil groups, the Gray‐Brown Podzolic and the Red‐Yellow Podzolic. The surface horizons of four soils representing the two great soil groups and one transitional soil were studied. The soils were: Cookeville (Red‐Yellow Podzolic), Loradale (Gray‐Brown Podzolic), Armour (Gray‐Brown Podzolic), and Pembroke (Red‐Yellow Podzolic—Gray‐Brown Podzolic transitional). Mechanical analyses showed that three of the four soils were silt loams, while Loradale was a silty clay loam. Mineralogical studies made of the clay fractions of these soils using X‐ray diffraction spectrometer and differential thermal analysis methods showed that chlorite, quartz, and kaolinite were prominent minerals in the clay fraction of the Cookeville soil. Kaolinite, illite, quartz and an interstratified mixture were the prominent components in the clay fractions of the other three soils.
Studies on Nitrogen Tie‐Up as Influenced by Location of Plant Residues in Soils
Authors: Parker D. T. , Larson W. E. , Bartholomew W. V.
Published: July 2010

In field experiments it has been observed that nitrogen availability to corn is frequently depressed where crop residues low in nitrogen remain on the soil surface as compared to where the residues are incorporated in the soil. The purpose of this investigation was to evaluate the immobilization of soil nitrogen as influenced by position of crop residue with reference to the soil.

In greenhouse experiments nitrogen uptake by Sudangrass was significantly greater when cornstalk residue was applied to the soil surface than when it was incorporated in the soil. By comparison with a treatment receiving no residue it was concluded that considerable nitrogen was immobilized by cornstalk residue incorporated in the soil, whereas no immobilization occurred with cornstalk residue on the soil surface.

On the other hand, in laboratory experiments it was demonstrated that soil nitrogen could be moved to and immobilized in low‐nitrogen residue on the soil surface and that the movement of nitrogen into surface residue was enhanced in treatments which were subsurface irrigated and in treatments held at a low‐air humidity. Also it was found in laboratory experiments that subsurface residue decomposed more rapidly than did surface residue and that this more rapid decomposition resulted in an increase in percent nitrogen but in a decrease in total nitrogen of the residue. Likewise, percent nitrogen of surface residue increased, but total nitrogen increased or decreased, depending upon the conditions of the experiment.

The results of a field experiment demonstrated that surface applications of low‐nitrogen residue without added nitrogen fertilizer resulted in decreased nitrogen uptake by corn and yield of corn. However, when nitrogen fertilizer was added along with the residue, yields were increased above the unmulched check.
The Correlation of Soil Phosphorus with the Yields of Ladino Clover
Authors: Welch L. F. , Ensminger L. E. , Wilson C. M.
Published: July 2010

Ladino clover (Trifolium repens) was grown in 11‐ by 6‐foot concrete‐walled field bins that contained three soil types representing large acreages in Alabama, namely Norfolk sandy loam, Eutaw clay, and Cecil clay. Soil samples were taken from the bins prior to seeding the clover and were extracted for soluble phosphorus by three extracting solutions. The solutions used were 0.05N HCl + 0.025N H2SO4, 0.5M NaHCO3, and 0.03N NH4F + 0.1N HCl. The procedure used with each solution can readily be adapted for rapid, relatively inexpensive tests as is required of a method to be used in a soil testing laboratory. The study consisted of 40 bins of each soil type, and because of past phosphorus treatments within a soil type, the bins differed greatly with respect to the amounts of soluble phosphorus present.

Six harvests were taken from the bins, three each in 1954 and 1955. The following correlations were made: relative yields for 1954 with soil test P2O5 values as determined by each solution on each soil type, relative yields for 1955 with soil test P2O5 values, and P2O5 values for one solution with values for another solution on a given soil type. All correlation coefficients were highly significant. Regressions equations were calculated for the regression of soil test P2O5 values on 1954 relative yield, 1955 relative yield, and total relative yield. Classes of soil test P2O5 values were calculated from the regression equations on the basis of the amount of P2O5, as indicated by soil tests, required to give a specified relative yield.

Data presented show that either of the three soil testing methods can be used satisfactorily as a basis for making phosphorus recommendations for the soils and crop studied. No one solution proved to be statistically better than the other two. All solutions tended to give higher correlation coefficients for the Eutaw and Cecil soils rather than for the Norfolk.
Calcium Phosphate Fertilizers: II. A Petrographic Study of Their Alteration in Soils
Authors: Lehr J. R. , Brown W. E.
Published: July 2010

As a supplemental study to pot‐culture tests in which six calcium phosphates were investigated, petrographic examinations were made of the fertilizer residues and surrounding soils. The materials tested were Ca(H2PO4)2 · H2O, CaHPO4 · 2H2O, CaHPO4, Ca4H(PO4)3 · 3H2O, Ca3(PO4)2, and Ca10(PO4)6(OH)2).

The purpose was to determine the physical and chemical alterations that the materials had undergone while in a soil environment and in the presence of feeding roots. Correlations between these observations and plant response were sought.

Some correlation was found between plant response and; (a) relative rates of solution or solubilities of the phosphates, and (b) chemical alterations of the phosphates. Positive evidence was found for 4 hydrolysis reactions, 2 of which confirm the postulated formation of octocalcium phosphate and apatite. Other observations lend new support to the concept of contact feeding by plant roots.
The Importance of Subsoil Phosphorus to Corn
Authors: Murdock John T. , Engelbert L. E.
Published: July 2010

In order to determine the depth to which the corn plant feeds, field studies were conducted to measure the recovery of P32 from successive 6‐inch soil horizons. The available soil phosphorus in these horizons was determined by the Truog, Olsen, and Bray No. 2 tests. The accuracy of these tests was checked by correlations with A values and phosphorus uptake data obtained from greenhouse studies.

Corn recovered more fertilizer phosphorus from the 6‐ to 12‐inch horizon of 2 of the 4 soils studied than from the plow layer and in the other soils recovery was almost as great as from the plow layer. Recovery from any layer below the 12‐inch depth was considerably less than from the top 2 layers, but the combined recovery from these lower layers was appreciable. This indicates that a large percentage of the phosphorus in the corn plant may come from the subsoil if the subsoil is fairly well supplied with available phosphorus. In most cases, the available phosphorus in the plow layer of the soils studied was greater than that in any of the respective subsoil horizons. However, it was much less than the combined amount found in all of the subsoil penetrated by corn roots.

According to the greenhouse studies the three phosphorus tests used gave an accurate measure of the available phosphorus in the subsoils as well as that in the plow layer.
Soil Compaction Zones as Affected by Conservation Cropping Systems
Authors: Elder William R.
Published: July 2010

The effects of soil compaction on rooting depth, aeration, and effects on erosion and drainage of Houston Black clay, a monotextured Grumusol are reported.

Field samples were taken over a broad area representative of definite nonconservation and conservation cropping systems. A single field was sampled on a sequence basis to measure the changes wrought by tillage from a perennial grass to a mature cotton crop.

Compaction zones were measured by the change in bulk density and structural index as compared to normal values for virgin soils or soils in good condition. Bulk densities and structural indices were determined by the use of a nonpolar liquid.

Compaction zones were common under continuous row crop systems.

Compaction zones form rapidly as a result of poor soil management, even within a single cropping season following a 2‐year period of perennial grass.