Soil Science Commons^™

Capillary-Diffusion And Self-Diffusion Of Liquid Water In Unsaturated Soils, Ronald E. Phillips, V. L. Quisenberry Jr.

KWRRI Research Reports

Capillary-diffusion coefficients were measured by use of inflow and outflow methods. With both methods the capillary-diffusion coefficients decreased very rapidly with decreasing water content. The lighter textured soils were found to have the higher diffusion coefficients over the entire moisture content range studied, 0 to 1 bar tension.

Self-diffusion coefficients were measured over a moisture content range from air dryness to saturation using ³H as a tracer of water. Each of the soils gave the same diffusion characteristics when the self-diffusion coefficients were expressed as a function of either water content or average number of water layers on the …

Relationship Of The Soil Water Content And Microclimate To The Plant Growth Water Use Relationship Of Several Plants, Philip Dean Sandberg

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Studies involving field plots, lysimeters, and garbage can lysimeters showed that an intermediate soil water level produced the most growth for a given amount of water use by oats, corn, and barley. For crested wheatgrass the lowest water level produced the most growth per water used. Field plots which were covered with sheet metal between the rows produced more plant growth per water used than the uncovered plots for the crops used in this study. One year's data were obtained on the effect of positioning the garbage can lysimeters. One half of the cans were placed on the soil surface …

A Comparative Study Of Boron Adsorption By A Calcareous And An Acid Soil, Namik M. Ali Rashid

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The adsorption of boron by Aiken clay loam and Vernal sandy loam was studied in the boron equilibrium concentration range of 0 to 40 ppm. Adsorption data were obtained at 11, 20 and 30°C. The data were analyzed by the application of the Langmuir adsorption isotherm. It was concluded that, in both soils, the adsorption of boron occurred on three distinct sites or regions.

The acid ferrigenous Aiken soil had a higher adsorption capacity for boron than the calcareous Vernal soil when compared on a unit mass basis. On the unit area basis, however, the Vernal soil adsorbed more boron …

The Effect Of Alternate Wetting And Drying On The Ammonium And Nitrite Nitrogen Transformation In Soils, Virupax C. Baligar

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Investigations were carried out to study the effect of alternate wetting and drying cycles on the mineralization, nitrification, and denitrification of soil nitrogen in two soils, in the presence or absence of added ammonium and nitrite. Soils were analyzed at the end of each drying cycle for total inorganic nitrogen, ammonium, and nitrite nitrogen. Gaseous products, i.e., ammonia, and the oxides of nitrogen (NO and NO₂) were collected in the course of drying for determination.

The drying cycles accelerated the rate of nitrogen mineralization in both soils and further increased the oxidation of applied and available ammonium. The …

Role Of Transition Metals In Nitrite Decomposition In Soil, J. S. Bajwa

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Iron and copper increased the decomposition of nitrite significantly during the first two hours of reaction when 150 parts per million (ppm) of nitrite and nitrogen was added to an acidic soil. Manganese was found to have a slight effect. There was no additional effect of the added metals after two hours reaction time.

The higher concentration of metals was not effective in catalyzing the decomposition of the added nitrite in nitrogen. All the added nitrite nitrogen was not recovered and the deficit could be due to the formation of nitrogen gas.