Physical Sciences and Mathematics Commons^™

Practical Improvements For Pivot And Surface Irrigation, Jonathan A. Holt

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Irrigation is critical to meeting global food and fiber demands. Optimizing agricultural irrigation may help sustain production levels, while reducing its demand for water. This research evaluated precision sprinklers and drip irrigation for pivots, five pivot track mitigation tools, three scientific irrigation scheduling (SIS) methods, sensors for surface irrigation cutoff, and automating surface systems to implement surge irrigation. With pivots and surface irrigation being the most common methods for irrigation in the West, small improvements from these tools could result in significant water savings.

Low energy precision application (LEPA) sprinklers and mobile drip irrigation (MDI) were tested on two pivots. …

Optimal Irrigation Management For Sloping, Blocked-End Borders, Jorge Jose Escurra

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A robust mathematical model of one-dimensional flow for sloping, blocked-end border irrigation was developed using the four-point implicit method to solve the Saint-Venant equations, the volume-balance solution method, and the implementation of new algorithms to avoid numerical instability and solution divergence. The model has the capability of successfully simulating all surface irrigation phases in blocked-end borders for a range of inflow rates (0.01 - 0.05 m³/s per m), longitudinal slopes (up to 1.00%), and border lengths (100 - 500 m).

To achieve numerical stability over the specified parameter ranges, the model was divided into three parts: (1) advance-phase …

Boron Composition Of Alfalfa In Utah As Related To Soils And Irrigation Waters, Robert N. Radtke Jr.

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Eighteen field plots at 15 locations were selected throughout the state to evaluate the status of the boron content in irrigation waters, soils, and alfalfa (Medicago sativa) plant tissue under irrigated conditions.

No boron deficiency symptoms were observed in any of the alfalfa plants at any of these locations, nor were any of the plant tissue boron levels inadequate. Only two locations were found in which the alfalfa plants exibited toxicity symptoms. These locations were along the Indian and Antelope Creeks in Duchesne County which contain high boron levels in the water. All the alfalfa and soil tested …

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 Irrigating With Saline Water On The Energy Status Of Water In Soil And Plant, Rolando H. Braun

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

1. Changes in the energy status of water that occurred in Milville silt loam and in bean (Phaseolus vulgaris L.) plants growing on it , during two consecutive 6-day periods while being irrigated with saline solutions, were studied.
2. Total soil water potential (Ψ soil) (measured with thermocouple psychrometers), matric-potential (Ψ_m) (measured with tensiometers) were considered. In leaf samples, the total water potential (leaf) and the osmotic potential (Ψ_π)--after freezing-- were determined with thermocouple psychrometers; by difference, the pressure potential (Ψ_p) was obtained.
3. There is no evidence of close relationship between changes taking place in …

Movement Of Atrazine In Soil Under Furrow Irrigation, Jyothi Veerabhadrappa

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Movement of atrazine in response to furrow irrigations was studied using the samples of Timpanogos silt loam soil. Distribution in soil profile of surface applied herbicide was determined by drawing samples of water extracts through porous cylinders. Atrazine quantity was determined by spectrophotometer.

It was observed that the herbicide found in the water extracts was an indication of the quantity present in the soil. The herbicide moved readily with the applied water. Irreversible thermodynamic model could not be applied because of the initial and final boundary conditions. The pattern of movement was in conformity with the chromatographic theory.