Soil Science Commons^™

A Model To Predict The Effect Of Salinity On Crop Growth, Stuart W. Childs

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A model is developed to predict the effects of soil salinity on crop growth. As an outgrowth and extension of the modelling efforts of Nimah and Hanks (1973a) and Gupta (1972), this model makes these principal assumptions in order to arrive at a quantitative relationship: 1) relative yield for a growing season is directly related to the ratio of actual and potential transpiration. 2) Water uptake by plants is in response to the water potential gradient between the plant at the soil surface and the soil surrounding the plant roots. 3) the effect of salinity on crop growth is solely …

Distribution Of Available Phosphorus In The Subsoil Of Selected Pedons Of The Warm Springs Series, Duane Altman Lammers

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The Warm Springs soil series which contained variable amounts of subsoil available (sodium bicarbonate extractable) phosphorus was studied to explain the variability and distribution of the NaHCO₃-P in the subsoil. Four pedons ranging in subsoil NaHCO₃-P from less than 10 ppm to greater than 30 ppm were selected in an area of less than 200 ha located on a nearly level, low lake terrace east of the Great Salt Lake in Weber County, Utah.

The morphology of each pedon was described in the field and samples collected from each genetic horizon or contrasting layer. Each soil …

Effect Of Drilling Fluid Components And Mixtures On Plants And Soils, Shahnaz Honarvar (Asad Sangabi)

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Using greenhouse pot techniques, 32 drilling mud components were tested to see if, at a high rate of addition, they reduced plant growth. Green beans and sweet corn were the test plants. The excellent black, silt loam, slightly acidic, uncultivated Dagor soil (Cumulic Haploxeroll) was used for most tests. Rates used were considered to be abnormal level (high rate) and usual (low rate) amounts that might be added in commonly used drilling muds.

Drilling mud components that caused no observable or statistically significant reductions of plant yield are the following: Super Visbestos, (Asbestos), asphalt, Ben-Ex (a vinyl acetate and maleic …

Evaluating The Availability Of Organic Nitrogen In Soils, Saleh M. Romaih

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The main objective of this study was to evaluate the organic N in silty clay loam soil as an indicator of soil fertility. The incubation method was used in this study. The NO₃ -N, the total N percent, and the organic matter were determined. The soil which was used in this study came from Evans Research Farm. The samples were taken from two different N experiments which were adjacent to each other. The soil samples were taken in October-November, 1973, after the crop had been harvested. These two experiments had different cropping histories.

The results of the first experiment …

Residual Nitrogen As It Affects Soil Fertility Under Irrigated Agriculture In A Tropical Wet-Dry Climate, Don Carlos Kidman

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

In the Zapotitan Valley near San Andres, El Salvador, Central America, an experiment was conducted to determine the availability of residual soil N to corn grown during the rainy season. This was an extension of an experiment conducted during the preceding dry season. The variables of the dry season experiment were irrigation method, crop, and rate of fertilizer N application. Soil NO₃-N and NH₄-N were determined by soil sample analysis to a soil depth of 120 cm by 30 cm depth increments. The samples were taken at the end of the dry season experiment and again …

The Contribution Of Subsoil Phosphorus To The Nutrition Of Alfalfa As Influenced By Soil Temperature, Reuel E. Lamborn

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

High bicarbonate-soluble phosphorus (P) in some Utah subsoils may affect the validity of fertilizer recommendations based on plow layer samples. The primary objective of this experiment was to determine the proportion of plant P derived from subsoils at typical Utah soil P levels and soil temperatures.

A calcareous soil very low in bicarbonate-soluble P was treated with various amounts of P and packed into deep pots to provide 24 centimeters of "topsoil" and 27 centimeters of "subsoil". Water baths in a growth chamber were used to control soil temperatures at 14 centigrade and 20 centigrade. Light, air temperature and humidity …