bluuebunny/crossref_metadata_2025 huggingface dataset:
Lime and Soil Acidity Effects on Alfalfa Growth in a Red‐Yellow Podzolic Soil
Authors: Moschler W. W. , Jones G. D. , Thomas G. W.
Published: July 2010

Rates of ground dolomitic and calcitic limestone ranging from 0 through 16 tons per acre were applied to Tatum silt loam at the time of seeding alfalfa in the spring of 1956. Lime has proved to be indispensable to yield and longevity. Total yields for three cutting years ranged from 0.25 to 8.0 tons per acre and stand survival at the end of the third cutting year varied from 0 to 95%. A true “critical level” of calcium or magnesium in neither soil nor plant was found. Rather, increases in the rate of lime applied were accompanied by gradual increases in soil pH, exchangeable bases, and percentage base saturation. In contrast, the application of relatively small amounts of lime reduced the exchangeable aluminum content of the soil sharply, and these reductions were closely correlated with increased alfalfa yields. Yields were in better agreement with base‐exchange saturation calculated from exchangeable metal cations than that calculated from metal cations plus exchangeable hydrogen. A slight and consistent increase in yield from dolomitic stone over calcitic stone was not significant. Depth of root penetration appeared not to be a factor contributing to the benefits from liming. Decrease in exchangeable aluminum in the soil and improved nitrogen metabolism are postulated as the chief favorable factors under the conditions of this experiment.
The Instability of Neutralized H, Al‐Bentonites
Authors: Davis Lannes E.
Published: July 2010

It is well known that the attainment of apparent equilibrium in the titration of acid clays is retarded. This phenomenon is frequently called “the titration lag.” Evidence is presented to demonstrate that the retardation is associated with exchangeable A1 in such clays. Hydroxide continued to react for several days with clay which contained appreciable exchangeable A1. The amount of hydroxide neutralized subsequent to titration of an acid bentonite which contained a minimal quantity of exchangeable A1 was small compared with the amounts which reacted with clays which contained larger amounts of exchangeable A1. It is tentatively concluded that Al+++ ions are in part covalently bonded, have a high activation energy, and react slowly with OH‐ ions.
Relationships Between Soil Properties and Red Pine Growth in Massachusetts
Authors: Mader D. L. , Owen D. F.
Published: July 2010

Results from a site study on 47 plots of plantation‐grown red pine in Massachusetts indicate that growth is related to organic matter and nitrogen contents of the soil profiles and soil drainage class. Multiple regression of 5‐year cubic foot volume growth per acre on total organic matter per acre of the solum and percent organic matter in the A horizon showed highly significant (1% level) partial and multiple regression coefficients. The regression accounted for 37% of the growth variability. The multiple regression coefficient for data on growth, log values for total nitrogen content per acre of the solum, and percent nitrogen in the A horizon from these plots also was highly significant, accounting for 35% of the variability in growth.

Regression using height growth of dominants from 20 to 30 years of age, height of dominants at age 25, or volume per acre at age 25 as a measure of growth gave poorer correlations with organic matter and soil nitrogen than 5‐year cubic foot volume growth per acre. A multiple regression equation relating eight soil factors to growth was highly significant accounting for 58% of the variability in growth and with highly significant partial regression coefficients for total nitrogen and drainage class.

Organic matter, nitrogen, and drainage class appear to have some value in assessing site productivity although residual variability from other growth factors, or from error in sampling and analysis, is still appreciable resulting in prediction errors on the order of 10% of the average volume growth rate. Cubic foot volume growth gave better correlations with site factors than either total or periodic height growth.
Effect of pH on the Cation‐Exchange Capacity of Surface Soils
Authors: Pratt P. F.
Published: July 2010

A method of measuring the pH‐dependent cation‐exchange capacity of soils is described and data for 15 surface soils are presented and discussed.

The pH‐dependent cation‐exchange capacity was found to be equivalent to the exchange acidity not displaced by a neutral KCl solution but displaced by buffered BaCl2‐triethanolamine solution. The average contribution of the organic C and clay to the pH‐dependent cation‐exchange capacity of the soil was 370 and 15.6 me. per 100 g. of the respective materials.
Release of Fixed Potassium from Soils by Plant Uptake and Chemical Extraction Techniques
Authors: Richards G. E. , McLean E. O.
Published: July 2010

Three Ohio soils of fine sandy loam, silt loam, and clay loam textures were subjected to treatments of comparable levels of potassium as KCl and K‐soil (exchangeable plus fixed K prepared by adding 1000 pounds per acre of K as KCl to portions of the same soils followed by successive wetting and drying). The soils were cropped to alfalfa in pots in the greenhouse for a period of six harvests. Potassium uptake by alfalfa was 76 to 95% as great from soils treated with K‐soil as from those with similar rates of KCl.

Following removal of the third crop, soil samples were taken and subjected to various chemical extractions. They included 1.0N NH4OAc extraction of both moist and dry soils, and extractions with 1.0N boiling NHO3. In general, none of these extractions gave a consistent indication of the residual K available to succeeding crops of alfalfa following initial K treatments and removal of the first three crops (cuttings). The results suggest some inadequacies in existing soil analyses for indicating residual K available to crops.
Comparative Rates of Decomposition in Soil of Wood and Bark Particles of Several Softwood Species
Authors: Allison F. E. , Klein C. J.
Published: July 2010

The rates of decomposition of 10 kinds of finely‐ground woods and the corresponding barks at two nitrogen levels were determined in the laboratory by measuring CO2 evolution over periods varying from 53 to 800 days. The following species were studied: California incense cedar, cypress, redwood, western larch, eastern hemlock, red fir, white fir, Douglas‐fir, red cedar, and Engleman spruce. The woods and barks of all of these species were considerably more resistant to biological attack than is shortleaf pine sawdust. California incense cedar, cypress, redwood, eastern hemlock, and red cedar, were decomposed to the extent of < 7% during a 2‐month period. The comparative resistance of woods and barks to decay varied for individual species but the average values for the 10 species were similar. Due to the slow rates of decomposition, the soil was able to furnish adequate available nitrogen for maximum rates of decomposition for all of the wood products, and supplemental nitrogen was not needed.
An Evaluation of Phosphorus Fertilizers Varying in Water Solubility: III. Oat Fertilization
Authors: Webb John R. , Pesek John T. , Eik Kalju
Published: July 2010

Nine field experiments were conducted in which phosphorus fertilizers differing in water solubility were compared for the fertilization of spring‐seeded oats. Methods of fertilizer application were also studied in five of the experiments. The tests involved rates of 15 to 75 pounds of available P2O5 per acre, and were located on soils which tested low in available P and had a pH range from 5.4 to 7.9.

The reaction of the soil appeared to be the most important single factor influencing the effectiveness of P sources and their method of application. In general, the degree of P water solubility assumed most importance in the experiments located on calcareous soils, while placement effects were of greatest significance on the acid soils.

In 3 of 5 experiments located on calcareous soils, there was a definite increase in yields with increasing water solubility of the P sources. However, the data were not comprehensive enough to permit the establishment of any critical level of water solubility.

Drilling the fertilizer with the seed was significantly superior to broadcasting in the three experiments involving placement studies on acid soils. Phosphorus sources differed only slightly in effectiveness on these soils.
Nitrogen and Phosphorus Composition of Corn Leaves and Corn Yields in Relation to Critical Levels and Nutrient Balance
Authors: Dumenil Lloyd
Published: July 2010

The relationship between corn yields and the N and P contents of corn leaves was determined in 93 fertilizer experiments by multiple curvilinear regression. The objective was to investigate critical levels and nutrient balance. Equal yields occurred at varying concentrations of N and P in the corn leaf within certain limits. The N or P content in the corn leaf at 95% of maximum yield varied with the concentration of the other nutrient because of their significant interaction on yield. Hence, the critical N or P level is not a point nor narrow range of values but includes a wide range of values depending on how it is defined and on the level of the other nutrient in the leaf. The N‐P nutrient balance appeared to be critical only at or near the maximum yield. Nutrient unbalance may occur when the leaf N or P content extends beyond a certain limit in relation to the other one.
Influence of Ca and Sr Amendments on Sr96 Uptake by Ladino Clover Upon Prolonged Cropping
Authors: Romney E. M. , Alexander G. V. , Nishita H. , Larson K. H.
Published: July 2010

Prolonged cropping experiments showed that a single application of CaCO3 in the amount recommended to produce better crop growth (2 to 5 tons an acre) continued to suppress Sr90 uptake from an acidic soil that initially was deficient in plant‐available Ca. This effect of treatment is attributable to the complementary ion influence of Ca on Sr. The cumulative amount of Sr90 removed by 15 successive cuttings of ladino clover was 29.38, 15.71 and 11.61% of the dose from Sassafras sandy loam treated with CaCO3 at levels of 1, 5 and 10 me. Ca per 100 g. soil (equivalent to 0.5, 2.5 and 10 tons CaCO3 an acre, respectively). The greatest amount of the Sr90 dose removed from the soil by a single clover cutting was 6.38% at the 1 me. Ca treatment.

A single application of Sr(NO3)2 amendment at levels of 0.05, 1 and 2 me. Sr per 100 g. soil (equivalent to 0.05, 1 and 2 tons Sr(NO3)2 an acre) initially increased plant uptake of Sr90 from Hanford sandy loam as a result of the displacement of Sr90 from the exchange complex by stable Sr into the soil solution where it was more readily available to the plant. This enhancing effect of low levels of Sr amendment on Sr90 uptake became less apparent as time progressed. The carrier‐dilution effect of reducing plant uptake of Sr90 from Hanford sandy loam was achieved by applying Sr(NO3)2 at a level of 10 me. Sr per 100 g. soil (equivalent to 10 tons Sr(NO3)2 an acre).
Preparation of Sensitive Linear Density Gradients
Authors: Beavers Alvin H.
Published: July 2010

A mechanical method is described for making linear density gradients sensitive to differences of 1 × 10‐6 g. per ml. Two miscible liquids of different densities are mechanically mixed to form a linear density gradient within the range of their densities. These gradients can be used for a wide variety of investigations such as density measurement of aqueous solutions and colloidal suspensions and measuring density changes accompanying chemical reactions.
Formation of Free Amino Acids in Rhizosphere and Nonrhizosphere Soil
Authors: Paul E. A. , Schmidt E. L.
Published: July 2010

Untreated samples of nonrhizosphere and soybean rhizosphere soils each contained about 15 identified free amino acids totaling 2 to 4 µg. per g. of soil; lysine was the most prevalent amino acid in each preparation. Numerous additional unidentified compounds occurred at concentrations estimated as 0.1 to 0.5 µg. per g. Treatment with glucose and potassium nitrate increased the amount of free amino acids to about 100 µg. per g. after 3 days. Concentrations declined after 3 days but still were 4 to 5 times that of the untreated control after 2 weeks' incubation. Glutamic acid was the dominant amino acid in all treated soils. Rhizosphere soil did not differ quantitatively from nonrhizosphere in samples treated with glucose, although a greater variety of ninhydrin reacting compounds was encountered in rhizosphere soil. Treated soils incubated at 20% field moisture capacity differed little in free amino acids from those held at 30%. The features of the free amino acid fraction are discussed.
Effect of Saline Water on the Growth and Chemical Composition of Beans: II. Influence of Soil Acidity
Authors: Lunin J. , Gallatin M. H. , Batchelder A. R.
Published: July 2010

Two greenhouse experiments were conducted to determine the relationship between soil acidity and salinity on the growth and chemical composition of snap beans.

One experiment was carried out on a Sassafras soil limed to give three pH levels. During the growth of the crop, four 1‐inch irrigations of dilute synthetic sea water having EC values of 2, 4, and 8 mmhos./cm. were applied as well as demineralized water. Growth depression with increasing salinity was greatest on the most acid soil. Increasing salinity depressed pH values and increased the availability of manganese in the soil and its uptake by the plant. Liming had the reverse effect.

The second experiment was conducted on the Portsmouth soil limed to give four levels of base saturation. Increasing salinity decreased soil pH but did not increase the availability of Fe, Al, or Mn to a level which might depress plant growth. Liming increased the yield of beans but no significant interaction between base saturation and salinity on yields was obtained. The chemical composition of the plant was more closely associated with the composition of the soil solution than the exchangeable cation composition. In some instances the interaction between salinity and base saturation treatments on plant composition was significant.
Characterization of the Sinai Soils
Authors: Wilding L. P. , Westin F. C.
Published: July 2010

The Sinai series comprises well‐drained Chernozem soils developed in calcareous, finely stratified, glaciolacustrine, silty clay loam and silty clay sediments. These soils occupy the nearly level to gently sloping tops of mesa‐like hills interlaced with a more or less continuous, moat‐like pattern of colluvial‐alluvial drains and swales. The profile has some characteristics of youthful grumusols. It consists of a black, granular A1 horizon; dark grayish‐brown or olive brown, compound prismatic‐subangular blocky B2 horizons; mottled light olive brown, prismatic B3ca horizons; and mottled light olive brown, laminated Cca or Dca horizons. Many vertical, dark‐colored tongues of A1 material extend into the B3ca horizons. Laboratory analyses of three profiles sampled in the northern, central, and southern areas of the Prairie Coteau of eastern South Dakota indicate that the northern samples contain greater quantities of organic carbon and total nitrogen than the southern samples. Field studies indicate that the southern soils have browner Ap and B2 horizons, more strongly developed B2 and B2ca horizons, and structural development to greater depths than the central or northern Sinai soils. These morphological and chemical differences are attributed to climatic and vegetative variations during their genesis.
Lithosolic Solodized‐Solonetz Soils in Southwestern South Dakota
Authors: White E. M. , Papendick R. I.
Published: July 2010

Solonetzic soils with thin calcareous sola occur in southwestern South Dakota. These profiles develop from sodium‐rich calcareous bedrock shortly after the bedrock is exposed by erosion. Dispersion and column formation probably occur when most soluble salts are leached. However, there is some Na2CO3 and the pH is high so CaCO3 solubility is reduced. Chestnut soils evolve if there is sufficient mineral‐mound Ca to replace the exchangeable Na. Otherwise, solodized‐Solonetz soils form without the aid of a fluctuating water table.
The Effects of Different Methods of Cornstalk Residue Management on Runoff and Erosion as Evaluated by Simulated Rainfall
Authors: Mannering J. V. , Meyer L. D.
Published: July 2010

The effects of three methods of cornstalk residue management on runoff and erosion were studied in the field on a Warsaw loam of 4 to 4½% slope and a Russell silt loam of 3 to 3½% slope. These methods were: (1) cornstalks as left by a cornpicker (check), (2) cornstalks shredded after corn was picked, and (3) cornstalks shredded and disked once. Simulated rainstorms at a constant intensity of 2.4 inches per hour were applied on each of two successive days by the rainulator, a field‐plot rainfall simulator. Infiltration, runoff, soil content of the runoff, and total soil loss were determined for both locations. Soil losses from the shredded treatment were < ½ the losses from the check treatment for both soil types. Since runoff from the two treatments were nearly identical, the reduction in soil loss was due to the lower soil content of the runoff. Soil losses from the shredded‐plus‐disked treatment were between those of the check and shredded treatments. Conclusions were (1) that shredding cornstalks in the fall can reduce soil losses significantly during the winter months and (2) that disking shredded cornstalks is undesirable from a soil conservation standpoint.
Plant Uptake and Fate of Soil‐Applied Zinc
Authors: Brown A. L. , Krantz B. A. , Martin P. E.
Published: July 2010

Greenhouse assays on 53 soils using sweet corn harvested in the vegetative state as an indicator crop showed 84% of the soils containing 0.55 ppm. or less dithizone‐extractable Zn responded to soil‐applied ZnSO4. Likewise, 76% of those above 0.55 ppm. dithizone‐extractable Zn did not respond to Zn applications. Generally Zn concentration in plants and total uptake increased with increasing rates of applied Zn. The average recovery of the applied Zn from 5 and 25 pounds per acre was 9.0 and 4.8%, respectively. Approximately 35% of the soil‐applied Zn was found as dithizone‐extractable after plants were harvested. Soil samples from several fields to which ZnSO4 had been applied indicated there may be a residual effect for several years. Laboratory studies with soil columns showed there was practically no downward movement of Zn as a result of leaching.
The Effects of Water and Fertilizer on Loblolly and Slash Pine Seedlings
Authors: Walker Laurence C.
Published: July 2010

Slash pine and loblolly pine seedlings in a Bladen clay loam soil were treated with water at four levels, from 4 inches above the ground to 4 inches below, for 2 years. Superimposed on these water treatments were three fertilizer levels to determine if fertilization in the presence of adequate and excessive moisture may result in growth responses and if fertilization may aid seedlings to overcome deleterious effects of high water tables.

Survival, height growth, needle length, foliage color, and foliar N, P, and K were influenced by both water and fertility levels. Draining these plastic soils of the Southeastern Tidewater area to depths of 4 inches below ground is recommended. Growth of both species during their first 2 years was increased appreciably by a spring application of 1000 pounds per acre of 8‐8‐8 plus 100 pounds per acre of a mixture of trace elements.
The Influence of Soil Moisture Regime and Phosphorus Source on the Response of Alfalfa to Phosphorus
Authors: Beaton J. D. , Gough Neville A.
Published: July 2010

The influence of soil moisture regimes and P sources on the response of alfalfa to P was studied in the growth chamber. Surface samples of two calcareous British Columbia soils, Machete stony sandy loam and the Nisconlith clay loam were used. Alfalfa yield and P uptake were highest when soil moisture tension was allowed to reach a maximum of 2.0 bars and subsequently reduced to 0.2 bars. The P sources were almost equally available with this regime.

Calcium metaphosphate and anhydrous dicalcium phosphate produced the highest yields. P content of alfalfa was highest with monoammonium phosphate on the Machete soil. Monocalcium phosphate resulted in the highest tissue P with the Nisconlith soil. Amount of P removed from the soil, with the exception of hydroxyapatitc, was not markedly influenced by P source. Hydroxyapatitetreated soil released the lowest amount of NaHCO3‐extractable P.
The Influence of Microclimate on the Morphology of Certain Soils of the Allegheny Plateau of Ohio
Authors: Finney H. R. , Holowaychuk N. , Heddleson M. R.
Published: July 2010

Transect studies of soil sequences have been made across four northwest‐southeast oriented valleys in southeastern Ohio. In general, soils occurring on southwestfacing slopes have an appreciably thinner A1 and more strongly developed A2 and B horizons than in the soils on the northeast‐facing slopes. The upper solum of the soils on the southwest facing slopes is also more acid and has wider C/N ratios. The differences noted in the soils appear to be closely related to the different microclimatic regimes and associated differences in vegetation. Physical and chemical data on soils are included.
The Effects of Rainfall Intensity on Soil Structure and Migration of Colloidal Materials in Soils
Authors: Bertrand A. R. , Sor Kamil
Published: July 2010

This paper presents the effects of rainfall energy on the clay content, specific surface, aggregate stability, and organic matter content of the several layers of three soil types.

After 30 minutes of simulated rainfall at an intensity of 1.6 inches per hour the magnitudes of the above properties of the first layer (0 to 1.5 cm.) decreased considerably, while these properties of the sublayers (1.5 to 12.0 cm.) did not change. After 30 minutes of rainfall at 2.8 and 4.0 inches per hour, the decrease in the magnitudes of these soil properties in the first layer was greater than that occurring under the 1.6 inches per hour rainfall. Thirty minutes of rainfall with intensities of 2.8 and 4.0 inches per hour changed the physical properties of the second layer (1.5 to 3.0 cm.) somewhat, although not of the same magnitude as they were changed in the top layer. The effects of 2.8 and 4.0 inches per hour rainfall were about equal in magnitude, while the effects of 1.6 inches per hour were lower.

Clays labeled with Rb86 migrated in soil profiles during the application of rainfall. About 1% of the clay migrated to a depth of 3 cm. At about 7.5 cm. the radioactivity of the soil was equal to the background.
Effect of Moisture Content on Tensile Strength of Unsaturated Glass Bead Systems
Authors: Vomocil J. A. , Waldron L. J.
Published: July 2010

Measurements were made of the applied tensile stress necessary to cause tensile failure of partially saturated samples of uniform sized glass beads.

Stress was applied by constraining a sample in a specially designed centrifuge head. The nature of the constraint and the position of the sample in the mount placed a tensile stress on the cylindrical sample. The stress was calculated from the centrifuge speed at sample failure.

The glass beads were cohesionless, i.e., when dry their interparticle attraction was essentially zero. The tensile strength of the partially saturated systems could therefore by analyzed in terms of the surface tension of the water films and the hydrostatic pressure of water bodies at contact points.

The theoretical tensile strengths do not agree with the experimental if the hydrostatic pressure is taken as the pressure used to desaturate the sample. Better agreement is obtained if the hydrostatic pressure used in the theoretical calculation is that predicted by capillary theory from observed water content.
Ionic Properties of Mica Surfaces
Authors: McDowell L. L. , Marshall C. E.
Published: July 2010

Seven micas were studied; muscovite, rose muscovite, phlogopite, margarite, biotite, lepidomelane, and a vermiculite‐biotite. Curves connecting selectivity number Ks with surface cationic composition were obtained for Li‐Na, Li‐Rb, Li‐Cs, Ba‐Ca, and Ba‐Sr exchange equilibria. The polyfunctional character of the surfaces is well shown in the monovalent series. Cesium is held less firmly than rubidium at biotite, vermiculite‐biotite and lepidomelane surfaces, and more firmly only in the case of phlogopite. Margarite is entirely different from the other micas, in showing a high bonding for lithium, and an order NH4 < Cs < Na < K < Rb. Potentiometric results, using clay membrane and silver electrodes, were obtained for Na+, Ag+ and Ca++ in 0.5% suspensions of the micas. The bonding energy curves also show the polyfunctional character of mica surfaces.
Soil Temperature and Soil Freezing as Affected by an Organic Mulch
Authors: Kohnke Helmut , Werkhoven C. H.
Published: July 2010

Temperatures and the occurrence of freezing and thawing of mulched and bare soil at 1‐, 4‐, and 10‐inch depths were recorded during a 5‐year period. A silt loam of fair drainage with a slight southern slope near Lafayette, Indiana was selected.

Average daily temperatures of mulched and bare soil varied only slightly: in winter the mulched soil was warmer by 1° or 2°F. This difference increased to 3° or 4°F. in the summer. Daily temperature fluctuations at the 1‐inch depth were twice as large in the bare soil as in the mulched soil. In the spring the soil temperature maxima reached favorable corn germination levels about 2 weeks earlier in the bare than in the mulched soil. At the 1‐inch depth the frequency of freezing and thawing was 3.6 times as great in the bare soil as in the mulched soil. At the lower depths these differences were less intense.

Twice as much total heat energy reached the one‐inch depth in the bare soil as in the mulched soil but the net heat energy retained was essentially identical in both treatments.
Magnesium Nutrition of Avocados under Sand Culture Conditions
Authors: Bingham Frank T.
Published: July 2010

Magnesium deficiency symptoms and associated leaf analysis were produced with Hass variety avocado trees grown under sand culture conditions during a 5‐year experiment. Correction of the deficiency by foliar sprays of Mg(NO3)2 was compared with root feeding with soluble MgSO4. Although some response to sprays was observed, it was concluded to be impractical. Deficiency was associated with leaf values of 0.20% Mg or less, with 0.10% indicative of an acute deficiency. Normal ranges are 0.30 to 0.60% Mg.
The Effects of Various Rates of Surface Mulch on Infiltration and Erosion
Authors: Mannering J. V. , Meyer L. D.
Published: July 2010

The effects of six rates of applied wheat straw mulch on infiltration and erosion were studied on a highly permeable Wea silt loam with 5% slope. Series of simulated rainstorms totaling 6.25 inches at an intensity of 2.5 inches per hour were used to evaluate the treatments. Mulch applications of 1, 2, and 4 tons per acre maintained very high infiltration rates resulting in essentially no erosion. The ¼‐ and ½‐ton mulch application lost 3 tons and 1 ton of soil per acre, respectively, whereas the check (no mulch) treatment lost 12 tons per acre. Benefits which were indicated from the mulching were: (1) reduced soil surface sealing as evidenced by higher infiltration rates, and (2) decreased rainfall and runoff energy for particle detachment and transport as evidenced by reduced soil content in the runoff.
Variation in Nutrient Content of Loblolly Pine Needles with Season, Age, Soil, and Position on the Crown
Authors: Wells C. G. , Metz L. J.
Published: July 2010

The nutrient content for the 17‐month cycle of loblolly pine (Pinus taeda) needles from the upper, middle, and bottom parts of the crown was determined for the first growth whorl of 1959. Needle weight per fascicle increased until April 1960 and then decreased slowly until abscission. Percentages of N, Ca, and Mg were greater in the needles from the bottom part of the crown, whereas P and K percentages were greater in the upper part of the crown. Percentage of N in the needles increased during winter months after the first growing season. Phosphorus percentage decreased each month for 1 year and then increased slightly. Calcium and Mg percentages in general increased throughout the growth and maturation of the needles with the content approaching a constant value during winter months. The basic influence of the soil on some plots was reflected in a two‐fold difference in Ca and a three‐fold difference in Mg content of the mature needles. It appears that about one‐half of the N, P, and K are translocated from the needles immediately before abscission.

The results of this study indicate that needles of the first growth whorl of the season at the top of the crown should be sampled in August and September of the first growing season for P; from December through March for K, Ca, and Mg; and from June through September of the second growing season for N.
The Occurrence and Cause of Iron Oxide Deposits in Tile Drains
Authors: Spencer W. F. , Patrick R. , Ford H. W.
Published: July 2010

A red sludge‐like deposit was found in several tile systems in Florida citrus groves. This deposit prevented the tile from functioning properly by blocking the passageway through which water entered the title. The deposit was found to be due primarily to “iron bacteria” which oxidize and precipitate reduced iron in the drainage water. Chemical analyses indicated a large proportion of the material was organic—probably bacterial cell bodies and waste products. The inorganic portion was mainly hydrated iron and aluminum oxides. Bacteriological studies of the material indicated the following genera of bacteria were responsible for the formation of the deposits: Gallionella, Leptrothrix, Thiothrix, Thiobacillus, Crenothrix and Cladothrix. The predominating genera within a tile line varied with location. The deposits occur in both bituminous pipe and clay tile whether installed in sawdust filter or wrapped with fiberglass. The relative amounts of the deposit in tile at various locations were related to the amounts of reduced iron extracted from the soils with an aluminum chloride solution.
Threads of Genesis in the Seventh Approximation
Authors: Cline Arvad J. , Johnson Donal D.
Published: July 2010

A common criticism of the newly proposed system of soil classification as presented by the Seventh Approximation is its apparent departure from the genetic aspects present in the older systems. Since so much of the published text is devoted to discussions of morphology, it is easy to understand why this impression is gained at first reading. However, the impression is faulty, and the relationship between the accepted theories of soil genesis and the Seventh Approximation is more specifically drawn than was this relationship in the older systems. The major difference being that in the Seventh Approximation the relationship to genesis is drawn by specific definitions of the kind of morphology representative of a kind or a degree of genesis rather than by direct reference to a genetic process itself or its degree of activity. In nearly every case the choice of morphological character selected to be definitive for a category is based on our understanding of how these characteristics represent a specific kind or degree of genetic process.

This constitutes both strength and weakness in the Seventh Approximation. Its strong relationship to genesis imparts a desirable sense of direction to the system. This same strong adherence may lead to faulty criteria or to improper selection of definitive morphological characteristics where our knowledge of genesis is imperfect. This last is inevitable under any conditions, and the advantages strongly outweigh the disadvantages.
Comparative Rates of Decomposition in Soil of Wood and Bark Particles of Several Species of Pines
Authors: Allison F. E. , Murphy R. M.
Published: July 2010

The finely‐ground woods and barks of 9 species of pine were allowed to decompose in soils in the presence and absence of additional nitrogen for periods of 63 to 800 days. Carbon dioxide evolution was measured at frequent intervals. The pine species studied were white, shortleaf, loblolly, slash, longleaf, ponderosa, western white, lodgepole, and sugar. An average of 16.2% of the wood carbon was oxidized in 60 days in the absence of extra nitrogen and 16.9% in its presence. The corresponding values for the barks were 8.7 and 8.6. The wood species showed variations in CO2 evolution during the 60‐day period, ranging from 8% for sugar pine to 51% for shortleaf pine. The variations for the barks were between 3.0% for white pine and 23.3% for lodgepole pine. Most of the pine woods decomposed somewhat more rapidly than did the other softwoods previously studied, but not nearly so rapidly as did the hardwoods. The pine barks are oxidized at about the same slow rate as are the other softwood barks.
A Test of the Validity of the Diffusion Equation for Unsaturated Flow of Soil Water
Authors: Rawlins Stephen L. , Gardner Walter H.
Published: July 2010

A review of the derivation of the diffusion equation from the potential equation for unsaturated flow of liquids in porous materials reveals that the only additional assumption required is that diffusivity is a unique function of water content. The validity of this assumption is tested by following absorption of water into a horizontal column of soil with a gamma ray densitometer. To ensure that required boundary conditions were met, the soil was evacuated to eliminate entrapped air or air pressure build‐up ahead of the wetting‐front; and water was applied quickly, evenly, and at constant negative head through a plane sintered glass bead plate, pressed against the bare plane end of the column to initiate flow. Diffusivity vs. water content curves constructed from these data reveal that diffusivity is not a function of water content alone.
Estimation of Particle‐Size Effects of Water‐Soluble Phosphate Fertilizer in Various Soils
Authors: Burns G. R. , Bouldin D. R. , Black C. A. , Hill W. L.
Published: July 2010

A laboratory method was developed for estimating the relative availabilities to plants of the P applied to soil in fertilizer particles differing in size. The method is based on the concept that the total availability of fertilizer P applied in particles of a given size is equal to the product of (a) the number of particles of that size, and (b) the summation of the availabilities of fertilizer P in the hypothetical small volumes of soil that may be considered to comprise the total volume of soil affected by a single particle. The method was applied experimentally to NaH2PO4·H2O particles of three sizes in each of six soils. In this application, appropriate quantities of a concentrated solution of P32‐tagged NaH2PO4 were used to stimulate the effects of fertilizer particles of different sizes, and particles of anion‐exchange resin were used to provide indexes of availability of fertilizer P in segments of the soil affected by one fertilizer particle. These values were integrated to obtain an index of total availability of fertilizer P. The indexes of total availability obtained from the laboratory data were in qualitative agreement with the relative availabilities of fertilizer P to plants in five of the six soils tested.
Moisture Conservation by Surface or Subsurface Barriers and Soil Configuration under Semiarid Conditions
Authors: Willis W. O. , Haas H. J. , Robins J. S.
Published: July 2010

Conservation of moisture under field conditions using black, polyethylene film and soil ridging was studied during a 2‐year period. Corn, in 42‐inch rows, was used as an indicator crop. Results show a minor surface ridge, 90% film‐covered, to be effective in conserving moisture and increasing yield and water use efficiency. Results also indicate that ridges without covering may conserve moisture. Subsurface barriers were not effective in moisture conservation or in increasing yields under the conditions studied. Good performance of the covered surface ridges is attributed to increased soil temperature in the spring, better utilization of light rains and suppression of evaporation losses. Supplementary laboratory studies of covered surface ridges substantiated the reasons given for improved moisture conservation.
Nutrition Research: Some Problems of the Total Tree Approach
Authors: Madgwick Herbert A. I.
Published: July 2010

Total tree analysis can yield an inventory of nutrients within a stand and, indirectly, a measure of nutrient uptake. The latter may be obtained more accurately by a combination of methods. Stand weight is best estimated by relating tree size to weight from large, intermediate, and small trees. Accurate estimation of nutrient concentrations requires sampling from additional size classes. Attempts to sample average trees yield biased estimates. The number of sample trees required per stand varies with stand characteristics. Five trees per plot gave average prediction errors between 7 and 23% for different parts of red pine trees. To be commensurate with the field work required, laboratory techniques should be of high quality and include analysis for a wide range of elements. Although too cumbersome for a diagnostic tool and, probably, too damaging for use in most permanent sample plots this technique can yield much basic information on stand nutrition and related problems.
Effect of Anions on the Sodium‐Calcium Exchange in Soils
Authors: Babcock K. L. , Schulz R. K.
Published: July 2010

Samples of Yolo fine sandy loam were leached with two series of solutions of solutions containing Na and Ca in which the composition varied. In each series the composition of the solutions in the corresponding solutions was the same except that in one series the anion was chloride and in the other it was sulfate. After leaching the samples to equilibrium, the exchangeable sodium was higher for the sulfate series than for the chloride series. This may be attributed to the effect of the different activity coefficients of the salts used. The results have significance for efforts to evaluate water quality.
Role of Biological Oxidation and Organic Matter Solubilization in the Subsidence of Rifle Peat
Authors: Hayes M. H. B. , Mortensen J. L.
Published: July 2010

Natural profile columns of Rifle peat were obtained by driving asphalt coated steel cylinders into the soil. The columns were incubated in the laboratory for a 102‐day preamendment period. Carbon‐14 labelled rye tissue was then mixed with the upper 6 inches of the soil profile and the columns were incubated for an additional 107 days. Irrigation water was applied and CO2 evolution and organic matter in the drainage water were determined throughout the incubation period.

The pattern of CO2 evolution and carbon balance relationships were considerably different from that obtained when small samples of disturbed, air‐dried peat were incubated with plant tissue. There was no evidence of “priming action” due to the addition of tissue, but considerable amounts of organic matter were lost in the drainage water. The addition of plant tissue reduced the rate of biological oxidation of Rifle peat. Tile systems should be placed below a horizon which adsorbs water‐soluble organic matter if loss of organic matter in drainage water is to be controlled.
Corn Response to Time and Rate of Phosphorus Applications
Authors: Seatz Lloyd F. , Sterges Athan J.
Published: July 2010

A greenhouse experiment was conducted to study the effects of rate and time of P applications on the growth and P uptake of corn. Different initial rates of P were applied and supplementary P was applied to make all treatments equal to the highest initial rate of 105 pounds P per acre. These supplementary applications were made to one set of each initial treatment at weekly intervals for 7 weeks after planting.

In most cases the yield was lower if the supplementary P was not applied within 4 weeks after planting. The higher the initial rate of P the longer the supplementary application could be delayed without yield reduction. In most instances the total P uptake was greatest when the supplemental P was applied 5 or more weeks after planting.

A critical period no doubt exists in the development of corn before which P must be available if it is to increase plant growth. If P becomes available after this critical period it will be absorbed by the plant and will be reflected in a higher percentage P composition.
The Effectiveness of a Cotton Bur Mulch and a Ridge‐Furrow System in Reclaiming Saline Soils by Rainfall
Authors: Fanning Carl D. , Carter David L.
Published: July 2010

A cotton bur mulch facilitated leaching of soluble salts by rainfall. Salt concentration was reduced in the surface 30 inches of soil to a level below that considered detrimental to growth of field crops. The high efficiency of salt removal by rainfall was attributed to flushing of salts from conducting pores when rains occurred combined with diffusion of salts from nonconducting to conducting pores between rains. Exchangeable Na percentage was also reduced to a low level. A ridge‐furrow system facilitated leaching of salts from below the furrows, but less effectively than the mulch system. Salts returned to the leached zones beneath the furrows, whereas no appreciable return was evident under the mulch. Either practice may prove useful in management of saline soils of the study area and similar locations.
Effect of Fertilizers on the Conductivity of Saturated Soil Extracts
Authors: Chapin J. S. , Fisher F. L. , Caldwell A. G.
Published: July 2010

Varying concentrations of fertilizers were mixed with Yahola fine sandy loam, Norwood silt loam, and Miller clay. Conductivity of the saturation extract was determined using a Wheatstone bridge. There was a marked difference in the conductivity caused by the different fertilizer materials. The fertilizers used are arranged in order of increasing effect (based on weight per unit of soil) on conductivity of the saturation extract: urea, ordinary superphosphate, concentrated superphosphate, phosphoric acid, monoammonium phosphate, diammonium phosphate, potassium sulfate, ammonium nitrate, and potassium chloride. Urea was unique in that the conductivity of the saturated extract increased with time of incubation.
Movement of Molybdenum in the Soil and its Effect on Availability to the Plant
Authors: Lavy T. L. , Barber S. A.
Published: July 2010

The processes involved in Mo availability to corn and soybeans growing in soil were investigated. Both mass‐flow and diffusion were involved. Mass‐flow caused Mo to accumulate at or in the root when the saturation extract contained more than 4 ppb. Mo. Diffusion patterns were usually obtained by autoradiographic procedures when the content was below 4 ppb. The saturation extracts of the soils investigated ranged from 2.2 to 8.1 ppb. Mo. The content of labile Mo in the soil varied from 41 to 211 ppb. of soil. The values of Dp/b for Mo varied from 0.5 to 8.4 × 10‐7cm.2 sec.‐1 and were much larger than for phosphorus.
Acidulation of Phosphate Rock in Soil
Authors: Terman G. L. , Moreno E. C. , Osborn Glen
Published: July 2010

Sulfur, H2SO4, H‐resin, and 20% superphosphate were compared as acidulants for phosphate rock (PR) as the source of P for corn grown on Hartsells fine sandy loam (pH 5.2 and 6.3) in greenhouse pot experiments. Effectiveness of granular fertilizers for supplying P to the crops decreased as follows: PR + superphosphate > PR + H‐resin > PR + S > PR alone. An intermediate size of granules of PR + S + soil was more effective than either coarser or finer material. H‐resin added to spots of PR in the soil was much more effective in solubilizing P than equivalent amounts of acid as H2SO4 or S. Acidulating PR in the soil with H‐resin or H2SO4 was considerably less effective for solubilizing PR than acidulation prior to application.
A Pedological Characterization of Five Profiles in Gray Wooded Soils Area of Minnesota
Authors: Harpstead Milo , Rust R. H.
Published: July 2010

Five soil profiles from the Gray Wooded soils area of Minnesota were investigated in the field for morphological characteristics and in the laboratory for physical, chemical and mineralogical properties. This Gray Wooded soils area has a cool humid climate, mixed coniferous and deciduous vegetation and the profiles studied were developed in well‐drained glacial till of late Wisconsin age.

X‐ray diffraction patterns revealed a wide variety of clay minerals. In most cases Ca2+ was the dominant ion on the exchange complex. The upper portion of the B horizon was the most acid part of the profiles with pH values as low as 4.7. Various types of clay films, found to be well developed in the argillic B horizons, were investigated in thin‐sections. The degradation of peds in the A and B horizon was also studied with thin‐sections.

A classification of these soils according to the 7th Approximation is suggested.
Evaluation of a Radioactive Tracer Method for Measuring Water Intake of Soils
Authors: Meek B. D. , MacKenzie A. J. , Stockinger K. R.
Published: July 2010

A tracer method of measuring water intake by application of radioactive gold in the irrigation water was evaluated. When irrigation water containing a constant known amount of isotope is applied to the soil, the amount of isotope adsorbed is proportional to the amount of water entering the soil. To calculate water intake the amount of isotope adsorbed is determined by measuring the activity of soil samples taken in the field. Two factors, vertical distribution of the tracer in the soil, and magnitude of adsorption on the soil surface from flowing irrigation water, were studied. The radioactive tracer was not measurably lost by adsorption from the tagged water as it flowed over the soil surface. It was adsorbed near the soil surface and sampling to a depth of 6 cm. recovered 95% of the gold in Holtville clay loam. The method was used to determine water intake variability. Samples within a plot had an average coefficient of variability of 9%. This would require 7 samples to determine the mean water intake within 10% at the 1% level.
Chemical and Physical Properties of Soils in a Wet Saline Area in Eastern North Dakota
Authors: Sandoval Fred M. , Benz L. C. , Mickelson R. H.
Published: July 2010

A large, imperfectly drained saline soil area in the Red River Valley of North Dakota (glacial Lake Agassiz) was characterized chemically and physically. Two main problem areas were differentiated: one where soils were derived from deep lacustrine sediments of low bulk density with high Mg content frequently, and another, where dense glacial till was close to the surface and was found similar in composition to deep artesian waters having higher contents of Na and B. Dolomite was high in the lakelaid soils with montmorillonite the principal clay mineral. Composition of shallow ground waters was similar to ambient soils. The principal problem is excessive concentrations of soluble salts influenced by shallow water tables. Several chemical and physical interrelationships are explained.
The Effect of pH on Potassium Fixed by an Irreversible Adsorption Process
Authors: Page A. L. , Ganje T. J.
Published: July 2010

The irreversible adsorption of K by soils, vermiculite, and illite under moist conditions was studied over a range of pH 3 to 8. The amounts of K irreversibly adsorbed by the vermiculite and soils that contained biotite‐weathering products were independent of the soil‐ or clay‐solution equilibrium pH as long as the concentration of Al in the systems was kept low. The results were interpreted to indicate that K, which is fixed by irreversible adsorption, is associated only with the permanent charge component of the exchange complex.

Acid‐leaching the soils destroyed their capacity to irreversibly adsorb K from KCl solution at pH 3 and markedly reduced their exchange capacities at the same pH. The acid‐leached soils contained relatively large concentrations of base‐titratable Al, which were nonreplaceable with either 1.0N NaCl or 1.0N KCL. Therefore, the results indicate that difficultly replaceable Al on the exchange sites of the acid‐leached soils prevented the adsorption of K on sites which were capable of irreversibly adsorbing it.