Physical Sciences and Mathematics Commons^™

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 …

The Influence Of Thermo-Gradients Upon Water Movement And Retention In Unsaturated Soils, Jose V. Salazar

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Temperature differences of about 5, 10, and 15 V, were applied to uniformly packed and insulated horizontal column of Millville silt loam soil using mean temperatures near 13, 14, 15, 16, 17, 18, 19, 20 and 23.5 C. The temperature distribution along the soil column was determined using copper constantan thermocouples. Soil samples were taken to determine volumetric moisture content, and soil water potential, using the vapor pressure psychometer technique. The thermodynamic flow equation of Taylor and Cary, (1964) was used to calculate the hydro-thermal transfer coefficient (ß) as given by:

-ß = d(μ_w)_T / dlnT

where …

The Influence Of Soil Moisture Regimes And Atmospheric Environments On Transpiration And The Energy Status Of Water In Plants, Sampatrao A. Gavande

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Plant responses to different soil moisture regimes have been extensively studied. Because of interactions between the soil, plant and climatic factors, few convincing generalizations concerning the influence of soil water on the transpiration of water by plants have been established. Generally single factors or at most the interaction of two have been studied at any one time. Useful theories describing the conditions of water retention in plant tissues and movement of water through plants have been proposed. Equally useful theories have been suggested for describing the retention and transmission of water in soil. The integration of these theories and their …

The Influence Of Organic Matter And Ph On Transformations Of Nitrites To Elemental Nitrogen, Mohammad A. Rashid

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Nitrogen occupies an important and prominent place in plant and animal nutrition. Large quantities are required by plants and must be available in the soil. Recently the use of nitrogenous fertilizers has increased manyfold. In view of the importance of this element in crop production, even greater use is anticipated in the coming years. In order to make full use of the applied nitrogen, continued investigations of soil-nitrogen relationship are imperative; however, this element presents many complex and challenging problems to investigators.

Influence Of Fertilizer Treatment On The Response Of Sugar Beet Yield To Moisture, Samad Farzanfar

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Many factors that influence the growth and quality of sugar beets behave in one way under one set of conditions and in quite another under other conditions. Consequently, these factors should be considered together under a dynamic situation to find their interrelations and their influence on sugar beet yield.

This study is a statistical analysis of the interaction of fertilizer and soil moisture potential with the yield of sugar beets grown in a crop rotation under different regimes of irrigation conducted over a period of seven years.

The data are available for the years 1949 through 1956, from an intensive …

The Influence Of Temperature On The Impedance To Water Flow Through Plants, Royal Duane Jensen

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This era has been termed the atomic or space age. The greatest concern of most people seems to be centered around survival from the destruction and suffering that might be caused by atomic and nuclear weapons. However, along with this, the world is confronted with perhaps a greater disaster--a potential calamity seldom realized by most people, yet a problem which grows more serious in the world each year--a tragedy which would probably be worse than destruction from nuclear weapons. This encroaching catastrophe is starvation.

Even today the majority of the people in the world do not have enough food. Each …

The Influence Of Soil Compaction Upon The Thermodynamics Of Soil Moisture, James E. Box Jr.

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The retention of water in soils is a very interesting subject. Soil-water research presents a great challenge to research workers. The challenge is broad in scope and extends from the field problems of large irrigation projects to the atomic scale of the solid-liquid interface.

If scientists are going to describe scientifically soil-water relations, they must ultimately utilize the instruments of science and the language of mathematics. To the end of the latter the mathematics of thermodynamics has been applied in these studies of water retention in soils.