Soil Science Commons^™

Some Aspects Of The Salinity Of Mancos Shale And Mancos Derived Soils, James C. Whitmore

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Initial studies to determine the thermodynamic solubility product (K_sp) of gypsum and CaCO₃ were conducted. The influence of different electrolyte salts at different concentrations upon the solubility of gypsum and CaCO₃ was then tested. Analytical data was utilized in conjunction with a computer to calculate the activity of CaCO₃ and gypsum, the ion pair concentration and the solubility product. Indifferent salts increased the solubility of gypsum and CaCO₃, and salts with a common ion decreased the solubility of gypsum and CaCO₃.

Lithium was found to be the dominant monovalent cation present …

Nitrogen Fertilization Studies In Dryland Winter Wheat And Potential Nitrogen Losses From The Soil At The Blue Creek Experimental Station In Northern Utah, Subhawat Intalap

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This study compared the effects of nitrogen sources on the available inorganic soil nitrogen, nitrogen movement, nitrogen losses, and wheat yields when nitrogen fertilizers were applied to soil planted to dryland winter wheat at the Blue Creek Experimental Station in northern Utah.

In the fall 1973 soil samplings, the fertilizers producing the largest mineral nitrogen contents in the 0-30 cm soil depths were ammonium nitrate >ammonium sulfate > S-coated urea, when they were broadcast at the practical rate of 56 kg N/ha. There was no increase in the mineral nitrogen at the dee per depths in the fall or at any …

The Accuracy Of Soil Mapping Units Of Certain Pachic And Cumulic Soils In Northern Utah, Behjat Badamchian

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The purpose of this study was to determine the accuracy of mapping of pachic and cumulic soils in Cache County. The soil maps that were used for this study as the basemap were the Atlas sheets of the published soil survey of Cache County.

Five map units from Mendou, Nebeker, Avon, Hendricks and Winn which include almost 52 percent of the pachic and cumulic soils in the survey area were selected for this study. These five soils cover large areas when compared to other soil series and they are distributed throughout the county. All these map units were recognized as …

Albedo Of The Earth's Surface -- A Comparison Of Measurements Taken On The Ground And From Flying Platforms, Frank D. Eaton

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The main objectives of this study were to develop the intricacies of reflected solar radiation from different natural surfaces and to show comparisons between values sensed in space of emergent radiation to ground values obtained from accounting for anisotropic reflection and estimating the effect of the intervening atmosphere. Thus, this study demonstrated that a prior knowledge of the angular distribution of reflected radiation allows determining the true hemispherical reflected radiation from a narrow field of view instrument such as found on a flying platform. Measurements for determining the indicatrices were made from a tower-mounted Nimbus MRIR and, in one case, …

A Model For Designing Surface Drainage Systems In Nearly Level Agricultural Lands, Rafael Maria Rojas

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The increasing demand for reclamation of periodically waterlogged nearly level agricultural lands in humid tropical areas and the hazard of soil deterioration and soil moisture balance disturbances by current land forming methods suggests the need for investigations of new surface drainage design procedures. This report presents a rainfall-runoff model for simulating hydrographs from ungaged agricultural plots. The model is based on routing procedures and utilizes common soil and hydrologic data. Tests made with several small agricultural water-sheds indicate that the model could be a useful tool in simulating surface drainage design.

Input data for the model consists of (a) rainfall …

Irrigation Scheduling Program For Sugarcane, Terence L. Pearse

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

An estimate of potential evapotranspiration is acquired to implement an irrigation scheduling program. Four equations, which estimate potential evapotranspiration (evaporation) were evaluated for prediction of Class "A" Pan evaporation. The equations used were Penman's combination equation, the Jensen-Haise temperature and radiation equation, and two of the Christiansen-Hargreaves polynomial regression type equations. Measured and calculated radiation was used together with two values of albedo. Four years of daily climate data from Rhodesia was evaluated by general linear regression methods.

Despite the significant variations between the four annual regression lines of each equation, the use of confidence intervals indicate that the Penman …

Modeling Spring Wheat Production As Influenced By Climate And Irrigation, V. Philip Rasmussen Jr.

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A model has been developed that predicts spring wheat grain and dry matter yield. Preliminary tests show very favorable results when predicting grain yield in two different climatic regimes, one being a dryland and another being an irrigated area. The strengths of the model lie in its simplicity, relatively available input data, and low computer processing time cost. Weakness of the model stem from the assumptions that allow its simplicity. The basic assumption in the model is that grain and dry matter yield can be related to the ratio of actual to potential transpiration, computed for each of five phenological …