bluuebunny/crossref_metadata_2025_split huggingface dataset:
Observations on Factors Influencing the Evaporation of Soil Moisture
Authors: Hide J. C. 
Published: July 2010

AbstractImportant variables which influence the rate of evaporation of soil moisture are (1) the vapor pressure difference between the layer from which water is evaporating and that of the turbulent atmosphere and (2) the resistance to vapor flow of the intervening layer. The vapor pressure difference is associated with the temperature of the layer from which evaporation is taking place and the temperature and relative humidity (vapor pressure) of the turbulent air. While capillarity moves water fast enough to keep the surface moist, the principal resistance to vapor flow is caused by the thin layer of nonturbulent air adjacent to the surface. Resistance increases rapidly as the surface dries so that water vapor moves through a thickening layer of dry soil. Adsorption of moisture by the dry layer and re‐evaporation associated with the diurnal temperature cycle complicate the process. Mositure movement in the upper layers of soil during the evaporation cycle was studied by periodic weighing of soil in vertically stacked porous bottomed containers and through the use of tensiometers. The data show the highly dynamic nature of the moisture regime in the surface layers of soil associated with diurnal temperature changes and the evaporation cycle.
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

AbstractA 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

AbstractThe 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

AbstractThe 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

AbstractFarm 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

AbstractA 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

AbstractThe 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

AbstractFrom 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

AbstractRedox 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

AbstractThe 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

AbstractPermanent‐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

AbstractExperiments 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

AbstractThis 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

AbstractPermanent 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.