bluuebunny/crossref_metadata_2025 huggingface dataset:
Water‐Stability of Aggregates from Potato Plots as Affected by Different Rotation Systems Under Irrigation in Western Nebraska
Authors: Mazurak A. P. , Valassis V. T. , Harris L. C.
Published: July 2010

A series of crop rotation plots under irrigation were established in 1912 on Tripp very fine sandy loam. From the series of rotations the following potato plots were selected for the study of water‐stability of aggregates: (i) continuous cropping of potatoes, (ii) 3‐year rotation (potatoes, oats or barley, sugar beets), and (iii) 6‐year rotation (3 years of alfalfa, potatoes, oats or barley, sugar beets). Neither manure nor fertilizer was added to these irrigated plots during the 39 years of the experiment.

The soil from the surface 2 inches of the potato plots was sampled and separated into 13 size fractions by means of rotary sieves. The resistance of aggregates in each size fraction to dispersion in water was obtained by shaking the aggregates in water for 2 and 2,000 minutes. The size distribution of aggregates in water was determined by means of sieves, elutriators, gravity and centrifugal sedimentation. The degree of aggregation of soil particles is expressed by the ratio:
urn:x-wiley:03615995:saj2sssaj195403615995001800030004x:equation:saj2sssaj195403615995001800030004x-math-0001

The size distribution of aggregates in water prior to any dispersion treatment is taken as that obtained by dry aggregate analysis, providing the aggregates are wetted either under partial vacuum or by capillarity. The ratios of geometric mean diameter for aggregates in water prior to shaking were 16, 10 and 31 for the continuous cropping, 3‐year rotation, and 6‐year rotation, respectively. Shaking the aggregates in water for 2 minutes produced a marked decrease in the ratios for the three plots: 1.79, 1.97, and 3.21. The marked decrease in the ratios in the 2‐minute shaking period indicates the instability of large‐diameter aggregates in water. The plot with alfalfa in the rotation showed a pronounced effect on the aggregation of soil particles as compared to the plots without alfalfa. Even after 2,000 minutes of shaking the aggregates in water, the plot with alfalfa showed a high degree of aggregation of soil particles. Highly significant regression coefficients were obtained with aggregation and clay content or total nitrogen content or apparent density of air‐dried aggregate or 15‐atmosphere tension values.
A Clay Mineralogical Study of Certain Reddish Prairie Soils of Oklahoma, with an Estimation of the Montmorillonite and Illite Content
Authors: Wilkinson G. E. , Gray Fenton
Published: July 2010

The clay fraction of the B and C horizons of a Dennis (from Pennsylvanian silty and clayey shale deposits) and two Kirkland soils (Permian Red Beds clayey deposits) were analyzed for the percentages of montmorillonite and illite.

In the analysis, the clay‐size material of the soil was separated into three fractions. Ethylene glycol retention, non‐exchangeable potassium, and cation exchange capacity determinations were made on each fraction. Percentages of montmorillonite and illite were computed.

The clay mineral contents of the Dennis and Kirkland soils were similar, with 35 to 50% montmorillonite and 20 to 25% illite in the B horizons and 40 to 50% montmorillonite and 20 to 35% illite in the C horizons.

The fractionation of the clay also permitted a study of the properties due to particle size distribution. Montmorillonite was found to be the predominant clay mineral in the <0.1 µ fractions and about equal with illite in the 0.6 to 0.1 µ fractions. Minerals other than montmorillonite and illite comprised a large portion of the 2.0 to 0.6 µ fractions.
Response of Sugar Beets to Potassium Fertilization in Relation to Soil Physical and Moisture Conditions
Authors: Larson W. E.
Published: July 2010

The relationship existing between the effects of potash fertilizers, physical and chemical properties of the soils and moisture tension treatments on the yield and potassium and sodium uptake by sugar beets in south central Montana have been studied.

Small sugar beet yield increases due to potash fertilizer were obtained on calcareous soils containing quantities of exchangeable potassium much in excess of what is usually thought to be adequate for maximum growth (i.e., from 0.82 to 1.79 m.e. per 100 grams soil).

Another experiment having moisture tension variables was conducted on a soil with relatively few large pores particularly at the 6 inch depth. Late in the season, sugar beets growing on low tension treatments showed evidence of potassium deficiency and petioles contained 31% less potassium than petioles from high tension treatments.

Since yield increases due to potash were obtained on soils with a very few large pores and maintained at low moisture tensions, it is suggested that poor soil aeration was a major factor contributing to the low potash availability. The lack of any relation between potassium uptake and the amounts exchangeable also may suggest that potassium absorption was dependent on soil aeration.
The Soil Survey in the Lawrence County, Tennessee, Farm Planning Program
Authors: Edwards Max J. , Overton Joseph R.
Published: July 2010

Farm operators in much of the Tennessee Valley have need for information that will aid them in better understanding and using their soil resources. A cooperative program was launched by the Tennessee Agricultural Experiment Station, the Extension Service, TVA, PMA, and BPISAE of the USDA, in Lawrence County, Tenn., to help meet this need. A detailed soil survey of the county, the first step in this program, was begun in 1948. This was a cooperative project involving the Tennessee Agricultural Experiment Station, TVA, and BPISAE. Soil maps of the separate farms were made subsequently. The soils, grouped according to their management requirements, were represented on these maps by distinguishing colors. A bulletin was published by the University of Tennessee in which the management requirements of each soil group were given for the crops important in the agriculture of the area. Group meetings of farmers were used as the chief channel through which the farm maps and copies of the bulletin were distributed and discussed by Extension workers.

Such a program is an approach to the task of bringing about a more efficient use of the farm resources that should be of interest to agricultural workers.
Characteristics and Vegetation Relationships of Some Podzolic Soils Near the Coast of Northern California
Authors: Gardner Robert A. , Bradshaw Kenneth E.
Published: July 2010

A survey of vegetation and soil of wild lands in Mendocino County in northern California was completed in 1951. This survey disclosed the occurrence near the coast of some distinct podzolic soil, unique in relation to most other soils of the state, of unexpected extent, and having in part distinct vegetation associations.

This northern coastal area has cool, nearly rainless but foggy summers and mild, wet winters. Precipitation averages between 35 and 40 inches; maximum temperatures during summer average about 65° F., and minimum temperatures during winter average about 40° F.; growing season is about 285 days.

This paper deals with morphological and some chemical and physical characteristics of three soil series, the Blacklock, Noyo, and Caspar; their geographical distribution along the coast on sandy deposits, and their vegetation associations. The Blacklock, a Ground‐Water Podzol, occurs on flat or gently sloping surfaces and supports a unique “pygmy” forest, chiefly of Bolander pine and Mendocino cypress. The Noyo and Caspar are of questionable great‐soil‐group classification but both are distinctly podzolic in character, the Noyo showing a stronger degree of podzolization than the Caspar. The Noyo supports a cover chiefly of Bishop pine and the Caspar chiefly one of redwood and Douglas‐fir.
Site Quality for Douglas‐Fir in Southwestern Washington and its Relationship to Precipitation, Elevation, and Physical Soil Properties
Authors: Carmean Willard H.
Published: July 2010

The objective of this study was to determine the effects of soil, climate, and topography on the growth of Douglas‐fir (Pseudotsuga menziesii var. menziesii (Mirb.) Franco) in southwestern Washington. The results indicate the productive capacity of forest land in this area in terms of permanent mappable features of the forest environment.

One hundred and fifty‐five even‐aged, second‐growth stands of Douglas‐fir were sampled. Total age and total height of dominant trees, slope, aspect, and topographic position were recorded. Descriptions of soil depth, soil consistence, elevation, and total annual precipitation were also made. Moisture equivalent and gravel content were determined for all soil horizons and in addition, the imbibitional water values of the substratum (C horizon) were measured.

The physical soil values and observed stand characteristics were assembled in a multiple regression that expressed tree height in terms of tree age and associated quantitative environmental conditions. The results of this statistical analysis are as follows:

1. Site quality decreases with an increase in elevation and with an increase in the gravel content and compaction of the soil layers above the substratum. 2. Site quality increases with an increase in total annual precipitation and with an increase in depth to the substratum. Increased site quality also occurred with an increase in the product of moisture equivalent and gravel content of the soil layers above the substratum, thus indicating that the adverse effect of gravel is not as pronounced with fine textured soils.

3. The above relationships are expressed by means of regression equations calculated for each of five different soil groups. Site tables suitable for field use in the identification of Douglas‐fir site quality may be prepared from these equations.
Permeability and Intake Rates of Medium Textured Soils in Relation to Silt Content and Degree of Compaction
Authors: Diebold C. H.
Published: July 2010

From 1948 through 1953, percolation rates were determined for 215 medium textured layers of soil from farmland in Arizona, Colorado, New Mexico, and Utah. Knowledge of the differences in percolation rates are helpful in establishing soil treatment units. This knowledge helps to indicate those areas most apt to be damaged by overirrigation, feasibility of reclamation of saline and alkali affected soils and to design effective drainage systems. Water‐intake rates for these layers of soil at field moisture were determined for the first 2 hours. In many cases they were compared with either irrigation intake rates or infiltrometer values. Thus, it was possible to locate not only limiting layers but also to develop clues for soils with different intake rates. The results were helpful in grouping soil units which have similar requirements for irrigation layout and tillage practices.

Medium textured soils, containing less than 2.5% organic matter, but more than 40% silt, behaved like silt loams and tended to have slow permeability and intake rates. In contrast, medium textured soils which contained less than 40% silt had moderate permeability and moderate intake rates unless they were compact and had few effective pores. Both permeability and intake rates varied with compaction of the soil. Three degrees of compaction or bulk density appeared to be significant. However, the limits for classes of bulk density were higher for sandy loams, sandy clay loams, and loams containing less than 40% silt than for the loams and silt loams containing 40% or more silt. Direction of natural breakage, especially in firm soils, and the number of effective pores per square foot were also important clues in evaluating permeability and intake rates. Each of these clues must be considered with reference to the others.
The Use of Redox Potentials in Studies of Soil Genesis
Authors: McKenzie L. J. , Erickson A. E.
Published: July 2010

Redox potentials have been measured in situ, with variations in time and space, in two well drained Podzols, McBride fine sandy loam, and in a Humic Gley Soil, Parkhill loam. In addition, redox potentials were studied in sand columns under an organic layer in a laboratory experiment.

Extremely low potentials persisted late into the growing season in the Parkhill loam, while low potentials were not observed in McBride fine sandy loam or in Marlette loam during the period from May to November. In McBride fine sandy loam and in Marlette loam, the surface horizon gave lower readings than the lower horizons during the summer months. In the Parkhill loam, the Ag horizons gave the lowest readings in the spring.

A redox profile was also observed in a study using sand columns under a humus layer. This was associated with a relatively greater amount of reduced iron in the upper part of a well drained sand column. It is postulated that this ferrous iron could be dissolved in the upper part of the solum, translocated, and then precipitated when it reached a higher oxidation zone lower in the soil profile. Additional studies are under way to test this hypothesis.

The measurement of redox potentials may be useful in studies of the development of Podzols, Ground Water Podzols, and Humic Gley soils.
Some Physical Factors that Influence Soil Erosion and the Influence of Aggregate Size and Stability on Growth of Tomatoes
Authors: Rai K. D. , Raney W. A. , Vanderford H. B.
Published: July 2010

The object of this investigation was to obtain quantitative laboratory data on the primary effects and interactions of aggregate size and stability, rainfall rate, soil slope, and surface condition on soil erosion by water.

Sharkey clay was treated at three rates with a modified vinyl acetate‐maleic acid compound to obtain three degrees of aggregate stability. The three soil samples were then separated into five size classes and subjected to the action of water under three different rainfall rates, three different slopes and two different surface conditions.

In this study size of aggregates had the greatest influence on the erosion of soil. As size was decreased from 1,000 to 500µ size, there was a slight increase in erosion but a much greater increase occurred as size was decreased further.

Surface condition, rate of rainfall and aggregate stability have a significant influence on all aggregate sizes, but slope influenced only the erosion of small aggregates.

The first order interactions were significant for small aggregates but the higher order interactions were not significant for any size class.

When 30% of the aggregates were water stable, the dry weight of both shoots and roots of tomato plants increased as the size of the aggregates increased. When 45% of the aggregates were water stable, however, the dry weight of both shoots and roots increased as aggregate size decreased.

The integrated effect of the large aggregates of lower stability was the same as small aggregates of higher stability. It is inferred that the former reduced in size during the growth of the tomato plants. Small aggregates of the lower stability reduced in size to such an extent that the moisture intake and transmission were impaired.
An Evaluation of Permanent‐Wilting Percentage, 15‐Atmosphere Moisture Percentage, and Hygroscopic Coefficient of Three Soils in Eastern Nebraska
Authors: Miller Scott A. , Mazurak A. P.
Published: July 2010

Permanent‐wilting percentage, 15‐atm. moisture percentage, and hygroscopic coefficient frequently have been used as indirect measures of the lower limit of readily available moisture for soils in situ. These three methods were evaluated by comparison with a field method for determining the lower limit of moisture readily available to sunflowers growing in Dickinson sandy loam, Wabash silt loam, and Sharpsburg silty clay loam. Since the locations of the soils occurred in a subhumid region, the soil sites were covered with plastic film about the base of the plant stems to rainproof the soils. Soil moisture percentages from 6 horizons of each of the 3 soils were obtained at frequent intervals during the 11‐week growth period preceding plant maturity.

Differences between the lower limit of readily available moisture in the field and the permanent‐wilting percentage were relatively small at all depths in the Dickinson sandy loam and Wabash silt loam, and in the surface foot of Sharpsburg silty clay loam. Permanent‐wilting percentages of Sharpsburg silty clay loam at depths of 12 to 18, 18 to 24, 24 to 30, and 30 to 36 inches were markedly less than the values of the lower limit of readily available moisture in the field. The 15‐atm. moisture percentage of puddled Sharpsburg subsoil was more reliable in predicting the lower limit of readily available moisture in the field than was the permanent‐wilting percentage. Alway's hygroscopic coefficient was the least accurate of the three indirect methods studied for estimating the lower limit of readily available moisture in the field.
The Effect of Soil Moisture Level on the Yield, Consumptive Use of Water, and Root Development by Sugar Beets
Authors: Larson W. E. , Johnston W. B.
Published: July 2010

Experiments were conducted to determine the effect of soil moisture level on yield, consumptive use of water and root development by sugar beets. The studies were made on areas with two water table depths to determine generally the extent to which sugar beets can use moisture in the moist zone immediately above a water table.

When sugar beets were allowed to remove 43, 75 and 95% of the available moisture in the root zone prior to irrigation, yields were 23.4, 22.0, and 16.9 tons per acre, respectively, on an experiment where plants could not obtain ground water. In a second experiment on an area with a water table at 4 to 4.5 feet below the soil surface, yields were 22.9 and 23.5 tons per acre when plants were allowed to extract 54 and 66%, respectively, of the available moisture prior to an irrigation. A third treatment not receiving irrigation, but drawing heavily on ground water, yielded 20.1 tons per acre.

Consumptive use of water for the growing season by sugar beets was 23.4, 22.5 and 19.0 inches, depending on whether 43, 75 or 95% of the available moisture was removed prior to an irrigation. The largest amount of water was lost from the surface foot of soil in all periods of measurement with progressively smaller amounts from deeper depths on the two wetter treatments. Moisture use was related to the depths containing available moisture in the dry treatment.

Moisture level had no effect on the rate of root extension or the shape of the commercial root.
Ion Exchange in Soil‐Plant Root Environments: II. The Effect of Type of Clay Mineral Upon Nutrient Uptake by Plants
Authors: Brown D. A.
Published: July 2010

This investigation was designed to measure the effect of the percentage of kaolinite, montmorillonite, and illite clay minerals upon nutrient uptake by soybean plants. A kaolinite‐montmorillonite and a kaolinite‐illite series of clay mixtures was prepared through the range of 0 to 100% kaolinite‐montmorillonite, and 0 to 100% kaolinite‐illite. Each clay mixture was mixed with nutrient‐free quartz sand to give 15% clay by weight. The sand‐clay mixtures, saturated to 70% Ca, 10% Mg, and 5% K, were placed in root development pans, and soybean plants were planted and grown between the collodion membranes for 4 weeks as described in previous studies. This enabled a measurement of the effect of the type of clay mineral upon nutrient uptake.

Within the kaolinite‐montmorillonite series, each increment of montmorillonite added altered the shape of the titration curve, and the exchange capacity in direct proportion to the percentage of montmorillonite clay present. This effect was also found for the kaolinite‐illite clay series. The experimental exchange capacity values of each clay mixture agreed with its calculated value, indicating that there was no gain or loss in the exchange capacities of the individual clay minerals upon mixing. Only 5% montmorillonite and 10% illite were necessary to dominate the chemical properties of the kaolinite clay minerals.

The uptake of Ca and Mg by plants was reduced in the 2.5% M‐97.5% K mixture, relative to that which occurred in 100% kaolinite; however, increasing the percentage of montmorillonite above 5% increased the amounts of Ca, and above 10% montmorillonite clay Mg increased in direct proportion to the increase of montmorillonite clay. The uptake of K increased progressively with each increment of montmorillonite clay included in the clay mixture. Within the kaolinite‐illite series, the total amount of Ca, Mg, and K taken up decreased due to the inclusion of 2.5, and 5% illite; however, with increasing percentages of illite, these cations were taken up in proportionally larger amounts. The ratios of K/Ca + Mg in the tops of the plant were altered, increasing from 1.4 to 1.9 due to the inclusion of 2.5% montmorillonite. Similar changes in this ratio occurred in the kaolinite‐illite series. Kaolinite released Ca and Mg in greater quantities relative to K than did the other two clay minerals. The data indicate that small percentages of montmorillonite or illite dominated the exchange properties of kaolinite and the resulting uptake of nutrients by plants.
The Effect of Crop Rotations and Soil Treatments on Soil Productivity
Authors: Hobbs J. A.
Published: July 2010

Permanent fertility studies were set up on the Agronomy Farm of Kansas State College in 1909 to determine the long‐time effects of crop rotations and of soil treatments on the productive capacity of the soil. Trends in soil productivity induced by the different rotations and the different soil treatments were analyzed for the 42‐year period 1911 through 1952.

The analysis showed that, despite improved wheat varieties used during the investigations, the yields of unfertilized wheat and of unfertilized corn were maintained only in a 16‐year rotation. Legume yields were not maintained in any rotation studied.

Wheat yields indicate how various combinations of commercial fertilizers, rock phosphate, lime, and manure increased the productive capacity of the soil. Corn yields indicate that only treatments including nitrogen increased soil productivity for this crop. Soil treatments increased alfalfa yields. Alfalfa yields, however, were not maintained at the original level by any soil treatment.
A Thermoelectric Method for Determining the Rate of Water Movement in Plants
Authors: Bloodworth M. E. , Page J. B. , Cowley W. R.
Published: July 2010

A thermoelectric method is described for the measurement of stream flow rates in the stems of plants. It has a definite advantage in that repeated measurements can be made on the same plant without damage to it. The method is quite simple and usually requires about 15 minutes for each measurement.

By subjecting cotton plants to different environmental conditions such as temperature, humidity, and wind velocity, it was found that the rate of water uptake and movement in the stem dropped from 114 cm./hr. to 76 cm./hr. when the wind velocity was changed from high to low. A temperature of approximately 99°F. and 20% relative humidity was maintained in both cases. With no wind movement but having a temperature of 82°F. and 62% relative humidity, the rate of water movement for the same plant was 38 cm./hr.

Present data show that this method is well adapted for indicating the effects of micro‐climate, soil moisture availability, and soil aeration upon the rate of water uptake and movement within intact plants. In addition, it has other uses which will be of interest to both the soil scientist and plant physiologist.
Zinc Solubility Under Alkaline Conditions in a Zinc‐Bentonite System
Authors: Jurinak J. J. , Thorne D. W.
Published: July 2010

The possibility of zincate formation in alkaline soils has been investigated. Utah bentonite suspensions were titrated to ½, 1, and 2% of their base‐exchange capacities with Zn65 in zinc chloride. The pH of the suspensions was varied by treatment with sodium, potassium, or calcium hydroxide. After a period of shaking, the suspensions were centrifuged and the supernatant liquid analyzed for Zn65.

In both the sodium and potassium systems, zinc solubility reached a minimum in the pH range of 5.5 to 6.7. As the alkalinity of the systems was increased, the solubility of zinc also increased. This suggests the formation of soluble alkali zincates. In the calcium system, zinc solubility reached a minimum at a pH of 7.6, and no increase in soluble zinc was noted as the pH of the system was increased. The formation of insoluble calcium zincate can be postulated. Since analyses did not reveal the ionic species of zinc in solution, this study can only be regarded as circumstantial evidence in support of zincate formation in alkaline soils.

The movement of various ionic forms of zinc was observed in a column of calcareous silty calay soil. Zn65 was applied to the surface as the zinc ion, the zinc‐ammonia complex, and the zincate anion at a rate equivalent to 50 pounds zinc per acre 6 inches. The columns were then leached with 18.6 inches of water. The zincate complex moved the furthest, being found at a depth of 3 cm.; the zinc ion and the zinc‐ammonia complex both moved to a depth of 2 cm. The difference in movement was attributed to the difference in sign of charge between the zinc treatments.
The Effect of Time of Top‐Dressing on Uptake of Phosphorus and Potassium by an Established Stand of Alfalfa
Authors: Seay William A. , Weeks M. E.
Published: July 2010

Plots of established alfalfa were top‐dressed with radioactive superphosphate and half the plots received potash. Top‐dressing dates varied from September to the following June. Entire plants were sampled at various periods after top‐dressing and divided into tops, crowns, and roots for analyses.

Conclusions were (1) P and K are translocated to crowns from roots and tops during autumn, (2) top‐dressed P is taken up by alfalfa even in the winter or dormant season, (3) in spring a rapid translocation of P and K from roots and crowns to tops occurs, (4) K fertilization does not affect P uptake from soil by alfalfa, (5) P fertilization does not significantly affect K uptake from soil by alfalfa although trends are more suggestive than the effect of K fertilization on P uptake, and (6) top‐dressed P was taken up to a greater extent from Hagerstown silt loam than from Nicholson silt loam which was expected in that chemical soil tests showed more available P in the Nicholson.
Effect of Soil Temperature and Soil Moisture on Manganese Absorption by Soybean Plants
Authors: Mederski H. J. , Wilson J. H.
Published: July 2010

Periodic field observations of the development of manganese deficiency symptoms in soybeans indicate that soil temperature and soil moisture may influence manganese absorption by soybean plants. These observations were explored in detail in a greenhouse study.

Glazed pots were filled with a manganese deficient clay soil, placed in constant temperature water baths and planted to soybeans. One bath was maintained at 15° C., a second at 27° C., while the third was maintained at 15° C. for the first 7 weeks of plant growth and increased to 27° C. for the remaining 5 weeks of growth. Two soil moisture levels were provided at each soil temperature.

A low soil temperature combined with high soil moisture was conductive to the development of severe foliar sympoms of manganese deficiency. High soil temperature combined with low soil moisture produced plants which exhibited only a slight manganese chlorosis. The total manganese per plant and the manganese concentration within the plant were significantly greater at the high than low soil temperature. In a solution culture study, increasing the temperature of the solution increased the manganese concentration in the soybean leaves indicating a physiological response of the plant to a change in root temperature.
The Response of Alfalfa to Borax Fertilizer on Illinois Soils
Authors: Russel D. A. , Kurtz L. T. , Melsted S. W.
Published: July 2010

A 2‐year study was made of the response of alfalfa to varying rates of borax fertilizer applied to Illinois soils. Fourteen locations differing in water‐soluble boron content, in soil type, and in the type of legume grown were selected; the trials at five of these locations were continued the second year. Borax fertilizer was applied in the spring of the first year (1952) on established legume stands at the rate of 0, 30, 60, and 90 pounds per acre. A randomized blocks design of nine replications was used in measuring the effect of the borax treatment upon seed yield, hay yield, and leaf‐to‐stem weight ratios. A modified Berger‐Truog quinalizarin procedure was used in measuring the water‐soluble boron content of the soils. Details of the modification are given.

On soils with low available boron tests, the observed deficiency symptoms were corrected by the applied borax fertilizer. Except for one location, hay yields were not significantly increased by the removal of the deficiency symptoms through borax fertilizer treatment. Seed yields were obtained at only one location, but the data for both 1952 and 1953 indicated that maximum seed production was not obtained even with a 90‐pound borax fertilizer treatment. Leaf‐to‐stem ratios, measured only in 1953, showed some variation with the rate of treatment but the data were not adequate to warrant any conclusions regarding the effect of borax on hay quality.

The general conclusion was that many of the soils in Illinois are at a stage of boron indigence at which boron deficiency symptoms are produced readily, especially under climatic extremes. In only a relatively few cases are the soils low enough in available boron to reduce the yield of alfalfa hay.
Factors that Influence Loss of Fall Applied Fertilizers and Their Probable Importance in Different Sections of the United States
Authors: Nelson L. B. , Uhland R. E.
Published: July 2010

The purpose of this paper is to attempt to reconcile observed differences in effectiveness of fall versus spring applied fertilizers between states, and to point out factors that influence loss of fall applied fertilizers and their probable importance in different parts of the United States. Particular emphasis is placed on nitrogen fertilizers.

Possibilities for leaching losses from fall applied fertilizers are evaluated from the standpoint of percolation of water from the soil in various areas and temperatures as they relate to conversion of ammonia‐nitrogen in fertilizers to leachable nitrate forms. On this basis, it appears that leaching losses would be negligible in the plains states and parts of Minnesota and Iowa. Progressing eastward, leaching from most soils is likely to increase, and fall applied nitrogen becomes questionable. In the South, where high percolation and temperatures predominate, fall application appears inadvisable.

Possibilities for losses from fall application are also discussed from the standpoint of erosion losses, volatilization of nitrogen, and immobilization and reversion of nutrients.
The Use of Soil Survey Information in an Area of Rapid Urban Development
Authors: Robinson Glenn H. , Porter H. C. , Obenshain S. S.
Published: July 2010

Urban, as well as rural planning, are necessarily influenced by certain soil properties such as drainage, permeability, type of parent material, soil texture, and depth to bed rock, water table, or an indurated horizon. These properties affect both sanitary measures and development costs. Information concerning soil characteristics of an area is contained in, or can be interpreted from, a soil survey map and report.

The Fairfax County (Virginia) soil survey is being made largely because of requests from the Fairfax County Planning Commission, a commercial planning firm, and a real estate agent. Local funds are made available to the Virginia Agricultural Experiment Station to defray a part of the costs. The Planning Commission and the commercial planning firm consider soil survey information vital for preparing an overall or master plan for Fairfax County. They feel that it is especially useful in zoning, planning septic tank sewage disposal systems, and agricultural planning, and that the same information is also useful in planning highways, recreational areas, and in arriving at equitable tax adjustments. If this survey meets their expectations in helping them answer questions related to rural and urban planning, it may lead to increased future demands for soil surveys.

It is desirable that persons trained in soil classification, management, and interpretation assist the various users of soil surveys. This assistance can be provided by personal consultation and carefully prepared descriptive legends and reports to accompany the map. The reports should include examples of how soils can be grouped for special purposes.

The expanding use of soil surveys presents a challenge to the soil scientist. It emphasizes the need for adequate classification of soils, closer field observations, improved field techniques, basic research, and careful interpretation of data.
Houston Black Clay, the Type Grumusol: I. Field Morphology and Geography
Authors: Templin E. H. , Mowery I. C. , Kunze G. W.
Published: July 2010

In most characteristic form the profile of Houston Black clay (the type specimen of the new group of Grumusols as proposed by Oakes and Thorp) consists of a (1) a very thick, much darkened, uneluviated A horizon of black calcareous clay 2 to 4 feet chick, (2) a slightly darkened transition several feet thick, and (3) substratum of marine clay or marl. Thickness of the black layer varies between ½ and 5 feet with position in the original pit‐and‐mound gilgai microrelief. All parts of the solum are equally clayey and, where exposed to thorough drying and moistening without confinement of volume, naturally crumble to a mulch of discrete grains. Volume change on moistening, plasticity, and stickiness approximate the maximum that occurs in soil. Free carbonates are present but lowest in the upper few feet, intermediate in total amount but partially segregated into concretions between depths of about 3 and 8 feet, highest in the relatively unaltered substrata.

This soil type, with an aggregate area of some 2½ million acres, is the most extensive of its kind in the United States and exemplifies the blackest, most plastic, and more crumbly (self mulching) variety of neutral to calcareous dark clay soils high in montmorillonite. Developed under prairie vegetation on smooth erosional upland in moist‐subhumid parts of the Gulf Coastal Plain, its occurrence is confined to outcrops of argillaceous limey rocks and related to a climate that gives alternating moistening and desiccation of the profile to depths of as much as 10 feet. Relations to some of the important closely related soil series are given. Total extent of such dark clays in the United States is a minor fraction of that in some tropical countries.
Fertilizer Evaluation: I. Fundamental Principles
Authors: Black C. A. , Scott C. O.
Published: July 2010

Evaluation of different fertilizer sources of a common nutrient is discussed in relation to the principles of quantitative biological assay. Criteria for examining the comparative effects of different fertilizers are described. Fertilizer effects are classified into different categories on the basis of these criteria. An approach is described for extending the methods of classical biological assay to cover certain practical cases that do not meet the theoretical requirement.
Ages and Development of Soil Landscapes in Relation to Climatic and Vegetational Changes in Iowa
Authors: Ruhe R. V. , Scholtes W. H.
Published: July 2010

Radiocarbon dates in Iowa indicate that specific upland soil landscapes can be referred to age ranges before present of: (1) > 25,000 years, (2) 16,000 to 24,000 years, (3) 14,000 to 16,000 years, (4) 12,000 to 13,500 years, and (5) < 11,000 years.

Paleofloras associated with the radiocarbon horizons as well as fossil pollen sequences of geologically correlative peats permit inferences regarding the vegetative and climatic environments relative to time of the specific upland soil landscapes. In Late Sangamon time (> 25,000 years) the soil landscapes were dominantly forested under a cool, moist climate. Forest dominated the landscape during Wisconsin time (24,000 to 11,000 years) under cold, moist glacial climatic regimes and cool, moist intraglacial intervals. A warmer grassland environment may have occurred in mid‐Wisconsin time (15,000 to 13,500 years). A cool, moist, arboreal environment may have culminated approximately 5,000 years ago. A warmer, subhumid to humid prairie environment became dominant at that time.

Such complex climatic and vegetative histories of soil landscapes relative to time should be considered in soil‐genesis studies in Iowa as well as in other similar areas.
Effect of Nutrition on Trifolium hirtum Inoculated with Rhizobium trifolii
Authors: Specht Alston W. , Erdman Lewis W. , Means Ura Mae , Resnicky John W.
Published: July 2010

The growth and chemical composition of Trifolium hirtum plants inoculated with effective strains of Rhizobium trifolii and grown in sand cultures in the greenhouse were studied in two experiments. In the first, element ratios remained constant, but a complete nutrient solution of three concentration levels with and without supplementary nitrogen was used. In the second experiment, two levels of supply each of potassium, calcium, and magnesium were used without supplementary nitrogen in a 2 × 2 × 2 factorial experimental design.

The highest yields in the two experiments were obtained in the first one when supplementary nitrogen was supplied to the plants in the nutrient solution. This indicated that in these experiments maximum yields were not possible with symbiotically fixed nitrogen alone. The data also indicate that symbiotic nitrogen fixation and yield of T. hirtum are closely related to the interrelation of the levels of supply of potassium, calcium, and magnesium. The results of these experiments show that this plant is very sensitive to its nutrient supply, and this characteristic suggests a delicate nutrient‐balance requirement to achieve the most efficient symbiotic nitrogen fixation and the best crop yields.
The Application of the Mitscherlich Equation for the Calculation of Plant Composition Due to Fertilizer Increments
Authors: Balba Monem A. , Bray Roger H.
Published: July 2010

The equation introduced by Mitscherlich has been generally used to express nutrient‐yield relationships as follows:

y = A(1—e‐eb‐ex)

This paper reports an attempt to apply such a curve to soil nutrient‐plant composition relationships, using the wheat plant. For this study soils deficient in phosphorus were selected in four different soil areas. All nutrients were supplied in adequate amounts except phosphorus which was added in five increments as superphosphate (0‐45‐0).

Wheat grain was analyzed for phosphorus and the constants for the above equation, after Bray's modification, were established. The equation arrived at was

y = 0.5834 (l—e‐0.03296b‐0.002097x)

where y is percent phosphorus in the grain, in the presence of x pounds of P2O5 and b pounds of soil phosphorus as determined by the soil test.

The equation, besides expressing quantitatively the soil nutrient‐plant composition relationship, may provide a means to differentiate between the amount of the nutrient taken up by the plant from the soil sources and that from the added fertilizer sources. The relative magnitude of the efficiency factors may be considered as a quantitative measure for the net relative availability of the nutrient forms involved. It may serve to predict the soil phosphorus level through the plant composition or vice versa.
Crop Response to NPK Fertilizers Varying in Granule Size and Water Solubility of the Phosphorus
Authors: Terman G. L. , Anthony J. L. , Mortensen W. P. , Lutz J. A.
Published: July 2010

Crop response to 7‐14‐14, 6‐12‐12, 10‐20‐20, and 11‐22‐22 fertilizers was determined on 5 soils in 2 greenhouse experiments in Tennessee and Virginia and in 21 field experiments in Georgia, Kentucky, Mississippi, North Carolina, Tennessee, and Washington. All soils were acid to neutral in reaction. The fertilizers, separately formulated from dicalcium phosphate, ammoniated ordinary superphosphate, ammoniated concentrated superphosphate, and diammonium phosphate, had 7, 27, 60, and 100%, respectively, of the phosphorus in a water‐soluble form. Each fertilizer was granulated and screened into 6–14, 14–35, and −35 mesh sizes. Early growth response, as determined in the greenhouse with oats and Sudangrass, and in the field with wheat forage and other crops, increased with smaller granule sizes of the low water‐soluble fertilizers but decreased with smaller granule sizes of the high water‐soluble fertilizers. This pronounced interaction of water solubility and granule size found at early growth stages did not persist in final yields of corn or wheat grain and vegetables in most experiments. Where an early growth response is desired, results indicate that fertilizers having a low water‐soluble phosphorus content should be granulated more finely than those having a high content of water‐soluble phosphorus.
Ion Absorption by Corn Roots as Influenced by Moisture and Aeration
Authors: Danielson R. E. , Russell M. B.
Published: July 2010

Using short‐term experiments, the uptake by corn seedlings of Rb86 from soil and from osmotic solutions has been measured under various levels of moisture stress and oxygen pressure. Soil moisture tensions, up to 12 atm., were developed using pressure plate apparatus appropriate to the tensions desired, and the osmotic studies were conducted with a highly porous, expanded perlite material wetted with aqueous solutions of mannitol. Continuous flushing with gas mixtures of air and nitrogen was used to maintain the oxygen partial pressures desired.

Moisture stresses developed from soil moisture tensions and from osmotic solutions differed markedly in their effect on Rb86 absorption. The ion uptake decreased rapidly with initial increases in soil moisture tension and leveled out at higher tensions to give a curve nearly logarithmic in nature. Increasing osmotic pressure caused only a slight decrease in absorption of Rb86 by the corn seedlings. The ion uptake from soil was nearly a straight line function of moisture content.

Initial increases in oxygen concentration of the gaseous environment at each level of soil moisture tension or osmotic pressure resulted in increased uptake of Rb86. In soil, however, the minimum oxygen content at which ion absorption reached a level value decreased with increasing soil moisture tension.
Measurement of Water and Air Permeability in Unsaturated Soil
Authors: Corey A. T.
Published: July 2010

Equipment developed for the measurement of oil and gas flow in oil producing sands was used to study unsaturated permeability in a soil. The method employs the simultaneous flow of air and water under the same pressure gradient to maintain a uniform tension and, as a consequence, a uniform saturation within the sample during permeability measurements. The saturation is reduced in increments by reducing the water pressure with respect to the air pressure.

Results of unsaturated permeability measurements on two relatively undisturbed samples of a sandy soil are presented. The interrelationship between gas and liquid permeabilities as a function of saturation is discussed, and a method of calculating the unsaturated water permeability from the more easily measured air permeabilities is suggested. The magnitude of gas slippage in a dry soil sample was determined by measuring the air permeability at several mean pressures and extrapolating the air permeability‐mean pressure function to an infinite pressure. The permeability to water of the saturated soil was only about half the permeability to air of the dry soil even when the air permeability was corrected for slippage.
Use of Thermistors for the Measurement of Soil Moisture and Temperature
Authors: Bloodworth M. E. , Page J. B.
Published: July 2010

Basic information on soil moisture availability for proper plant growth and development is essential in irrigated areas. This has practical applications for determining the rate and zone of moisture use by plants as well as the over‐all irrigation requirements of crops.

It has been recognized that the thermal method of soil moisture measurement offers one of the best possibilities of being unaffected by salt in addition to covering the available moisture range with acceptable sensitivity. By using a thermistor as a combination heating element and temperature indicator, it has been found that such a unit, when cast in a porous material, serves as an accurate moisture indicating device.

Laboratory experiments have indicated that this method of moisture measurement covers the available moisture range, with its greatest sensitivity near and below field capacity. The thermal units have been unaffected by salt concentrations normally found in agricultural soils.
The Potassium Supplying Power of Several Western Oregon Soils
Authors: Pope A. , Cheney H. B.
Published: July 2010

Soil samples from 20 sites representing 7 soil series were intensively cropped with Ladino clover in the greenhouse. The amounts of total and nonexchangeable potassium removed by the clover were determined. These values were then compared with the amounts of total and nonexchangeable postassium extracted by boiling 1N HNO3 and the amount of exchangeable potassium present in the soils before and after cropping.

The soils varied widely in their potassium supplying power. The total amount of potassium extracted by HNO3 was highly correlated with the amount of potassium removed from the soils by 10 successive cuttings of Ladino clover in the greenhouse (r = 0.959). The amount of potassium released from nonexchangeable forms by HNO3 was highly correlated with the amount released during greenhouse cropping (r = 0.937). The correlation coefficient for the total amount of potassium removed by the clover and the amount of exchangeable potassium in the soils before cropping was 0.852. The correlation between the amount of potassium released from nonexchangeable forms during cropping and the amount of exchangeable potassium before cropping was very low (r = 0.174).

Total potassium in the HNO3 extract and potassium released from nonexchangeable forms by HNO3 appeared to be better indexes than exchangeable potassium before cropping to potassium release and removal by intensive cropping with Ladino clover in the greenhouse.
The Effect of HPAN and IBMA on the Fixation and Availability of Potassium in Several Ohio Soils
Authors: Jones M. B. , Pratt P. F. , Martin W. P.
Published: July 2010

Solutions of K salts with and without conditioner were added to four soils in sufficient solution to bring the soils approximately to field capacity. The conditioners were HPAN (hydrolized polyacrylonitrile) and IBMA (isobutylene maleic acid). The treated soils were incubated for several days, oven‐dried at 68°C., and K fixation against extraction with NH4OAc was determined. The results indicated that K fixation was reduced by the conditioner treatments.

In a pot experiment, using corn and Sudangrass as assay plants, K was added at 2 levels with and without conditioner on 2 Ohio soils. High levels of N and P were added to all pots so that they would not be limiting factors. The yield and K content of corn and Sudangrass were greater on pots treated with conditioner and K than on pots treated with either alone. Possible explanations for the reduction in K fixation and greater availability of K resultant from treatment with conditioners are presented.